Homemade Speakers(chrisfenton.com)
chrisfenton.com
Homemade Speakers
http://www.chrisfenton.com/homemade-speakers/
70 comments
This comment covers much of what is wrong with common interpretations of acoustics.
> the human ear is largely insensitive to moderate variations in volume/frequency... but it's incredibly sensitive to phase.
No, it's not. The human auditory system is sensitive to time variation. Phase shift may contribute a time shift but only at frequencies low enough that their wavelength has reasonably relation to the spacing of the ears. For example at 10Khz the wavelength is far too short for 'phase' to impact arrival time. Ultimately what actually matters in this regard with the human auditory response is group delay, not phase.
> Phase is how we discern directionality (stereo), among other things.
As mentioned above, what matters in the context of what your saying is group delay, but that is far from the only thing that matters for directionality. The human psycoscoutic system is very complex, part of directionality is group delay, part of it is frequency attenuation caused by sound wrapping around the ear from the ear, part of it is a half dozen other things. 'Phase' doesn't come even close to being a catch all cause.
> To my ears, the best and most musical sounding speakers
And thus we've devolved from science, as this usually goes. What on earth does 'musical sounding speakers' even mean?
> It's very easy to measure frequency response. It's very hard to measure phase alignment.
I have no idea where you came up with this statement but it is very easy to measure the response of a loudspeaker, both in amplitude and phase.
> If you want to see serious map-over-territory thinking, look at THD specs for amplifiers. It's super-easy to measure THD - just isolate harmonics of a sine wave a 1khz.
THD can be measured at only 1Khz, but it isn't something intrinsic to what 'THD' means. Measuring at only 1Khz is generally indicative of a crappy amplifier manufacturer looking to inflate their power numbers. Proper specs will provide a 20-20kHz THD rating.
> Dynamic recovery behavior, intermodulation distortion, stuff like this is what gives amps their distinctive sounds - but it's nearly impossible to measure!
If an amp has a distinctive sound, it has failed to achieve it's core design goal. I'm not sure what you think is impossible to measure, but I assure you it is not.
> the human ear is largely insensitive to moderate variations in volume/frequency... but it's incredibly sensitive to phase.
No, it's not. The human auditory system is sensitive to time variation. Phase shift may contribute a time shift but only at frequencies low enough that their wavelength has reasonably relation to the spacing of the ears. For example at 10Khz the wavelength is far too short for 'phase' to impact arrival time. Ultimately what actually matters in this regard with the human auditory response is group delay, not phase.
> Phase is how we discern directionality (stereo), among other things.
As mentioned above, what matters in the context of what your saying is group delay, but that is far from the only thing that matters for directionality. The human psycoscoutic system is very complex, part of directionality is group delay, part of it is frequency attenuation caused by sound wrapping around the ear from the ear, part of it is a half dozen other things. 'Phase' doesn't come even close to being a catch all cause.
> To my ears, the best and most musical sounding speakers
And thus we've devolved from science, as this usually goes. What on earth does 'musical sounding speakers' even mean?
> It's very easy to measure frequency response. It's very hard to measure phase alignment.
I have no idea where you came up with this statement but it is very easy to measure the response of a loudspeaker, both in amplitude and phase.
> If you want to see serious map-over-territory thinking, look at THD specs for amplifiers. It's super-easy to measure THD - just isolate harmonics of a sine wave a 1khz.
THD can be measured at only 1Khz, but it isn't something intrinsic to what 'THD' means. Measuring at only 1Khz is generally indicative of a crappy amplifier manufacturer looking to inflate their power numbers. Proper specs will provide a 20-20kHz THD rating.
> Dynamic recovery behavior, intermodulation distortion, stuff like this is what gives amps their distinctive sounds - but it's nearly impossible to measure!
If an amp has a distinctive sound, it has failed to achieve it's core design goal. I'm not sure what you think is impossible to measure, but I assure you it is not.
I'm not devolving from science. I'm pointing out that science is insufficiently evolved to truly understand the domain.
I'm a musician and a recording engineer. I've made records, I listen to real-world instruments every day, I've built speakers, and I've built amplifiers. And I've learned along the way that "accurate" is a big stinking pile of BS, and "scientific" is usually just a euphemism for magical thinking - "If we can't measure it, it doesn't exist". If you can't measure it, maybe you don't understand the problem as well as you thought.
You don't get to ignore the evidence of the senses of domain experts just because it makes you uncomfortable.
I'm a musician and a recording engineer. I've made records, I listen to real-world instruments every day, I've built speakers, and I've built amplifiers. And I've learned along the way that "accurate" is a big stinking pile of BS, and "scientific" is usually just a euphemism for magical thinking - "If we can't measure it, it doesn't exist". If you can't measure it, maybe you don't understand the problem as well as you thought.
You don't get to ignore the evidence of the senses of domain experts just because it makes you uncomfortable.
I think you are wrong to dismiss domain experts opinions as leaving science. Machine learning 101 is eye ball your data, as the human brain is the most powerful pattern matcher known. A musicians ear is therefore the best tool for detecting anomolies in sound and should not be dismissed for not having a nice mathematical construction. Acoustics are perceptual and are heavily filtering the real world sound waves so I don't think its possible to reduce the laudatory cortex to simple filters like its ignoring phase or whatnot.
> A musicians ear is therefore the best tool for detecting anomolies in sound
This is only true if you can remove biases.
This is only true if you can remove biases.
Gah, not A/B testing nonsense.
Want an A/B test? Put your hi-fi in the same room with a real singer, or an acoustic guitar, or whatever musical instrument, and see how hard it is to tell them apart. Not very, I assure you.
Interestingly, we can pick up very subtle and useful musical cues from very poor recordings and reproduction. It's a complex thing.
Want an A/B test? Put your hi-fi in the same room with a real singer, or an acoustic guitar, or whatever musical instrument, and see how hard it is to tell them apart. Not very, I assure you.
Interestingly, we can pick up very subtle and useful musical cues from very poor recordings and reproduction. It's a complex thing.
> For example at 10Khz the wavelength is far too short for 'phase' to impact arrival time.
It's the time-of-flight difference between when the one ear receives the wave front and the other from a change in the sound that gives us the directional information.
Absent any change all we have to go on is volume so we rotate our heads to the point where both ears receive the signal equally strong, then the source is somewhere in the plane that bisects the head of the listener.
Rotating one ear forward gives us the clue about whether the sound source is in front of us or behind us. (Fails to work when it is directly overhead.)
It's the time-of-flight difference between when the one ear receives the wave front and the other from a change in the sound that gives us the directional information.
Absent any change all we have to go on is volume so we rotate our heads to the point where both ears receive the signal equally strong, then the source is somewhere in the plane that bisects the head of the listener.
Rotating one ear forward gives us the clue about whether the sound source is in front of us or behind us. (Fails to work when it is directly overhead.)
It's the time-of-flight difference between when the one ear receives the wave front and the other from a change in the sound that gives us the directional information.
That's part of it, the other part is the head related transfer function is the change in response of sound due to diffraction effects caused by the head, upper torso and pinnae. The pinnae also help us to judge elevation.
That's part of it, the other part is the head related transfer function is the change in response of sound due to diffraction effects caused by the head, upper torso and pinnae. The pinnae also help us to judge elevation.
> If an amp has a distinctive sound, it has failed to achieve it's core design goal.
What makes you think the design goal of an amp is always to have perfect sound reproduction? That may be true for a home-theater system or if you're playing wind/string instruments, not so for a guitar amp. We have the (digital) tools to get pure, 100% uncolored sound, and musicians hate it.
What makes you think the design goal of an amp is always to have perfect sound reproduction? That may be true for a home-theater system or if you're playing wind/string instruments, not so for a guitar amp. We have the (digital) tools to get pure, 100% uncolored sound, and musicians hate it.
These are "bookshelf monitors", and the whole point of a monitor is to be accurate!
The comment to which I replied to was an absolute statement, not referring to the monitor built. Maybe if he had said "If a monitor has a distinctive sound [...]" that might have been closer to truth; in practice it's nearly impossible not to have a distinctive sound, there are too many variables at play.
> in practice it's nearly impossible not to have a distinctive sound, there are too many variables at play.
Of course not. High-end monitors are high-end precisely because they achieve indistiguishability. Between to pairs of speakers from different brands, you wouldn't be able to tell the difference.
Of course not. High-end monitors are high-end precisely because they achieve indistiguishability. Between to pairs of speakers from different brands, you wouldn't be able to tell the difference.
This goes absolutely against the real-world experience of professional mixing and mastering engineers, people who make their livings on "accurate" reproduction of music. Speakers are not accurate, period. Anyone who has been both a musician and a mixing engineer (like me) will tell you this. The idea of "accurate" response from audio systems is magical thinking.
The mixing and mastering engineers aren't trying to make some perfect reproduction of natural sound. They're trying to make records that sound as good as possible on as many different kinds of reproduction systems as possible - not just "perfect" audiophile systems, but car speakers, iPods, etc. As such, rather than going for accurate speakers, mix engineers rely on speakers that they know very well, so they can predict results elsewhere more easily.
The most popular professional mixing speaker is the Yamaha NS-10. It's not "accurate". It doesn't even pretend to be accurate. In fact, it has a pronounced peak and significant harshness around 2khz, right in the most sensitive area for vocals and midrange melodic instruments. Why use it? Because if you can make it sound good on the NS-10, it'll sound good anywhere. Likewise, the second most popular speaker is the Auratone, a single driver with limited frequency range. The Auratone has two advantages. First, it reflects the limited construction of many real-world speakers. Second, because it lacks a crossover, there's no phase weirdness in the midrange, so it's actually very pure at the most musically critical points. Deep bass and sizzly highs aren't important. Midrange is important, and Auratones are brutally honest at that, more than speakers costing orders of magnitude more.
The mixing and mastering engineers aren't trying to make some perfect reproduction of natural sound. They're trying to make records that sound as good as possible on as many different kinds of reproduction systems as possible - not just "perfect" audiophile systems, but car speakers, iPods, etc. As such, rather than going for accurate speakers, mix engineers rely on speakers that they know very well, so they can predict results elsewhere more easily.
The most popular professional mixing speaker is the Yamaha NS-10. It's not "accurate". It doesn't even pretend to be accurate. In fact, it has a pronounced peak and significant harshness around 2khz, right in the most sensitive area for vocals and midrange melodic instruments. Why use it? Because if you can make it sound good on the NS-10, it'll sound good anywhere. Likewise, the second most popular speaker is the Auratone, a single driver with limited frequency range. The Auratone has two advantages. First, it reflects the limited construction of many real-world speakers. Second, because it lacks a crossover, there's no phase weirdness in the midrange, so it's actually very pure at the most musically critical points. Deep bass and sizzly highs aren't important. Midrange is important, and Auratones are brutally honest at that, more than speakers costing orders of magnitude more.
Are they? I haven't had the chance to compare two monitors in the same room, but as far as I know no two are alike, and none has ever achieved a perfectly flat response curve. Take also high-end headphones, where it's way easier to have a similar acoustic profile, yet any two models with similar characteristics (on paper) are very easy to tell apart.
There's no such thing as a perfectly flat response, but that's not what you need: what you need is response flat enough that it is within human ear resolution.
(As far as I remember, headphones are actually harder to get precise response curves due to the interaction with the skull and precise physiology of the listener, but I may be mistaken in that.)
The problem with any claim from people that they can "easily" tell two pairs of headphones apart or two pairs of monitors apart is that most of the time these claims are not scientifically validated. There are numerous biases and gotchas involved in measuring audio fidelity, and one must be aware of these when designing experiments. (And the whole "audiophile" industry is based on the idea of selling snake oil technology to people with fat wallets and who think that they have better ears than anyone, and they go to great lengths towards denying the science.)
(As far as I remember, headphones are actually harder to get precise response curves due to the interaction with the skull and precise physiology of the listener, but I may be mistaken in that.)
The problem with any claim from people that they can "easily" tell two pairs of headphones apart or two pairs of monitors apart is that most of the time these claims are not scientifically validated. There are numerous biases and gotchas involved in measuring audio fidelity, and one must be aware of these when designing experiments. (And the whole "audiophile" industry is based on the idea of selling snake oil technology to people with fat wallets and who think that they have better ears than anyone, and they go to great lengths towards denying the science.)
Likewise, it's very easy to write off actual observation as "bias" when the test isn't "scientific". That's one of my big gripes with what I thin of as the right wing of the hi-fi industry... the idea that human experience can be reduced to measurable and mechanically reproduceable observation in all cases. This reaction leads to "blame the observer" rather than questioning whether the scientist actually understands the problem domain or the question they're asking sufficiently well. It's every bit as emotional and reactionary as the "left wing" hi-fi subjectivists. But at least the subjectivists are owning up to their magical thinking.
Both your comments are heavyweight so I'm not trying to pick sides. (Sum your two perspectives and I think you're close to Ultimate Expert Comment.) I just want to mention that beat is talking about phase alignment between identical signals, which our perceptual network is incredibly sensitive to. Anyone who has ever done multi-mic recording can attest to the very real effect you can hear from lack of phase alignment, even if they have bronze ears. Even worse is if you duplicate two musical recordings and offset one, even by a tiny amount.
This is a critical aspect of crossovers- since they contain the same signal, any phase differences between the intersecting components are easy to pick up by the ear and very difficult to measure since it won't show up as a significant frequency or amplitude differential. In the highly acoustically sensitive area where the crossover occurs, the phase distortion between the two signals is hard to pin down but it's definitely there, it's easy to hear by A/Bing.
I mix on a multiple-monitor setup and the one that is most critical to me sounds like absolute garbage. However, it has a wonderfully "flat" response and allows you to get an idea of what proven aesthetically-unpleasing issues are present. It has no crossover. The goal is not to have perceived rumble, tinniness, or mud on any of the incredibly wide range of listening systems out there. I think this is what beat means by "musical"- flat speakers are actually not pleasant to the ears, but the most empirically useful.
The most famous secret of many respected mix engineers is the Auratone. Michael Jackson's "Bad" was mostly mixed on this little thing. It sounds like absolute garbage aesthetically but reveals more issues in a mix than anything else. It's like when you first saw things under a "blacklight" as a kid and got to see all the particulate matter covering everything, that you can't see with the naked eye.
Here's more about the Auratone. I hope my comment has helped to bridge this critical area of "musicality" vs. empiricism. http://www.trustmeimascientist.com/2012/02/06/auratone-avant...
Postscript- the listening environment is the most important aspect! Always! You can have the best mastering grade monitors on earth in an improperly treated room, and it's all for naught!
This is a critical aspect of crossovers- since they contain the same signal, any phase differences between the intersecting components are easy to pick up by the ear and very difficult to measure since it won't show up as a significant frequency or amplitude differential. In the highly acoustically sensitive area where the crossover occurs, the phase distortion between the two signals is hard to pin down but it's definitely there, it's easy to hear by A/Bing.
I mix on a multiple-monitor setup and the one that is most critical to me sounds like absolute garbage. However, it has a wonderfully "flat" response and allows you to get an idea of what proven aesthetically-unpleasing issues are present. It has no crossover. The goal is not to have perceived rumble, tinniness, or mud on any of the incredibly wide range of listening systems out there. I think this is what beat means by "musical"- flat speakers are actually not pleasant to the ears, but the most empirically useful.
The most famous secret of many respected mix engineers is the Auratone. Michael Jackson's "Bad" was mostly mixed on this little thing. It sounds like absolute garbage aesthetically but reveals more issues in a mix than anything else. It's like when you first saw things under a "blacklight" as a kid and got to see all the particulate matter covering everything, that you can't see with the naked eye.
Here's more about the Auratone. I hope my comment has helped to bridge this critical area of "musicality" vs. empiricism. http://www.trustmeimascientist.com/2012/02/06/auratone-avant...
Postscript- the listening environment is the most important aspect! Always! You can have the best mastering grade monitors on earth in an improperly treated room, and it's all for naught!
> I just want to mention that beat is talking about phase alignment between identical signals, which our perceptual network is incredibly sensitive to.
I wouldn't go that far. If you have two signals emitting from physically separate location and they are out of phase, you just get comb filtering. Is it audible? It can be, but its not the phase you're hearing, it's the drastic frequency notching in amplitude. More importantly, you're going to get comb filtering no matter what you do with a multi-speaker setup. Just move your head a couple inches out of the ideal sweet spot equidistance from each speaker and you'll have created an effective phase shift and get the same type of comb filtering. In other words even with a theoretically perfect pair of time aligned speakers with perfect cross-overs, you'll still get comb filtering if you take various measurements around the listening area. Just moving the mic 4 inches can have drastic effects on the measured response. Incidentally if you've ever seen someone taking a measurement with a sound meter and rhythmically moving the mic around in a strange fashion, they are doing that to try to even the effects of comb filtering.
> This is a critical aspect of crossovers- since they contain the same signal, any phase differences between the intersecting components are easy to pick up by the ear and very difficult to measure since it won't show up as a frequency or amplitude differential.
If you're taking a measurement in the crossover region and there is a phase shift between the drivers you most certainly will see an effect in amplitude as you'll have at least partial wave cancellation. You can certainly take measurements in locations what won't show this, but that is always true. You can take measurements of a perfectly time aligned speaker that make it look like it has phase issues too, if you put the mic in the right spot.
Likely the largest improvement you get from time alignment of the drivers in a multi-way speaker is the ability to control vertical lobe tilting, but you can 'fix' that issue with MTM layouts without time aligning the drivers as well.
I wouldn't go that far. If you have two signals emitting from physically separate location and they are out of phase, you just get comb filtering. Is it audible? It can be, but its not the phase you're hearing, it's the drastic frequency notching in amplitude. More importantly, you're going to get comb filtering no matter what you do with a multi-speaker setup. Just move your head a couple inches out of the ideal sweet spot equidistance from each speaker and you'll have created an effective phase shift and get the same type of comb filtering. In other words even with a theoretically perfect pair of time aligned speakers with perfect cross-overs, you'll still get comb filtering if you take various measurements around the listening area. Just moving the mic 4 inches can have drastic effects on the measured response. Incidentally if you've ever seen someone taking a measurement with a sound meter and rhythmically moving the mic around in a strange fashion, they are doing that to try to even the effects of comb filtering.
> This is a critical aspect of crossovers- since they contain the same signal, any phase differences between the intersecting components are easy to pick up by the ear and very difficult to measure since it won't show up as a frequency or amplitude differential.
If you're taking a measurement in the crossover region and there is a phase shift between the drivers you most certainly will see an effect in amplitude as you'll have at least partial wave cancellation. You can certainly take measurements in locations what won't show this, but that is always true. You can take measurements of a perfectly time aligned speaker that make it look like it has phase issues too, if you put the mic in the right spot.
Likely the largest improvement you get from time alignment of the drivers in a multi-way speaker is the ability to control vertical lobe tilting, but you can 'fix' that issue with MTM layouts without time aligning the drivers as well.
I think what one might crudely call the "audiophile phase beef" is not about the comb-filtering that results from misalignment but the non-linear phase response of most crossovers, before the signal hits the air. Most act somewhat like an all-pass filter: a flat frequency response but varying delay across the frequency spectrum. This doesn't affect frequency sweeps or white noise, but results in impulses and clicks being smeared out in time or ringing a bit. The thought among some is that this is audible on percussion sounds, but experimental evidence is dubious as far as I can see. There are some references in the classic Douglas Self crossover book: http://books.google.co.uk/books?id=D9l6JWKKSzUC&lpg=SA2-PA14...
A similar argument which I think more people would agree with is that reflex-loading a speaker hurts the low-frequency group delay, the lack of which is one reason suggested for the supposed clarity of the classic NS10 monitor: http://www.soundonsound.com/sos/sep08/articles/yamahans10.ht...
A similar argument which I think more people would agree with is that reflex-loading a speaker hurts the low-frequency group delay, the lack of which is one reason suggested for the supposed clarity of the classic NS10 monitor: http://www.soundonsound.com/sos/sep08/articles/yamahans10.ht...
> incredibly sensitive to phase
Under contrived situations such as square waves and headphones. However, in general, the ear is not particularly sensitive to phase. [0] [1] which both discuss, in particular, [2] and [3] as well as many others listed in their bibliographies.
The stated conclusions are, emphasis mine, "Given the data provided by the above cited references we can conclude that phase distortion is indeed audible, though generally speaking, only very subtly so and only under certain specific test conditions and perception circumstances." [1]
Reads may also be interested in an additional conclusion which reads thusly: "Room acoustics further masks whatever cues that the hearing process may depend upon to detect the presence of phase distortion." [1]
[0] http://www.silcom.com/~aludwig/Phase_audibility.htm
[1] http://www.audioholics.com/room-acoustics/human-hearing-phas...
[2] Lipshitz, Stanly P., Pocock, Mark, and Vanderkooy, John, "On the Audibility of Midrange Phase Distortion in Audio Systems,' J. Audio Eng. Soc., Vol. 30, No, 9, Sept. 1982, pp 580-595.
[3] Toole, Floyd E., "The Acoustics and Psychoacoustics of Loudspeakers and Rooms - The Stereo Past and the Multichannel Future," 109th AES Conv., Los Angeles, Sept 2000.
Under contrived situations such as square waves and headphones. However, in general, the ear is not particularly sensitive to phase. [0] [1] which both discuss, in particular, [2] and [3] as well as many others listed in their bibliographies.
The stated conclusions are, emphasis mine, "Given the data provided by the above cited references we can conclude that phase distortion is indeed audible, though generally speaking, only very subtly so and only under certain specific test conditions and perception circumstances." [1]
Reads may also be interested in an additional conclusion which reads thusly: "Room acoustics further masks whatever cues that the hearing process may depend upon to detect the presence of phase distortion." [1]
[0] http://www.silcom.com/~aludwig/Phase_audibility.htm
[1] http://www.audioholics.com/room-acoustics/human-hearing-phas...
[2] Lipshitz, Stanly P., Pocock, Mark, and Vanderkooy, John, "On the Audibility of Midrange Phase Distortion in Audio Systems,' J. Audio Eng. Soc., Vol. 30, No, 9, Sept. 1982, pp 580-595.
[3] Toole, Floyd E., "The Acoustics and Psychoacoustics of Loudspeakers and Rooms - The Stereo Past and the Multichannel Future," 109th AES Conv., Los Angeles, Sept 2000.
"So they sell what looks good on paper... THD"
From an EE perspective most of the "obvious" ways to screw up THD sound truly horrible. Crossover distortion, clipping, bias problems, truly excessive hum or noise...
Also note that just because your final PA is a modern class D doesn't mean there's not some opamp input stage in the box that is perfectly liable to classical transistor bias problems. So you can't get crossover distortion out of a modern class D amp final device as an inherent part of how those switch the transistors, but that doesn't mean you can't screw up the input stage of the opamp that is inside the box of an amp that none the less has a D-type output final stage. In terms of circuit design, A guy who can design a nice class D stage is not necessarily (but often is) the same guy who can design a class A or AB stage.
"Necessary but not sufficient" is a good way to describe good THD numbers.
I would have to think for awhile how to get a good THD number with foul intermod numbers... Maybe if you fed in two noise signals outside the freq bandwidth that when nonlinear mixed gave a difference freq of 2 KHz that would sound horrible even if a pure sinewave input at 1K sounds awesome. It would take some work to screw up an amp this way but it could happen.
Anyway nothing says "tradeoff" like engineering and I wouldn't trade off a pretty basic core characteristic like THD for improved ... anything, except maybe power level. I'd rather hear something good than something a couple dB louder. Reporting good THD is valid in marketing as a way to tell that you did at least the very first homework problem... I agree totally with you that there are multiple steps beyond it, but there's no point in working on any of them if you can't pass the first simple THD test. (Edited to add, I missed the PERFECT analogy: Its like passing the UL Labs certification that it probably won't burn your house down. That's kinda required, and its also possible to aim a little higher)
From an EE perspective most of the "obvious" ways to screw up THD sound truly horrible. Crossover distortion, clipping, bias problems, truly excessive hum or noise...
Also note that just because your final PA is a modern class D doesn't mean there's not some opamp input stage in the box that is perfectly liable to classical transistor bias problems. So you can't get crossover distortion out of a modern class D amp final device as an inherent part of how those switch the transistors, but that doesn't mean you can't screw up the input stage of the opamp that is inside the box of an amp that none the less has a D-type output final stage. In terms of circuit design, A guy who can design a nice class D stage is not necessarily (but often is) the same guy who can design a class A or AB stage.
"Necessary but not sufficient" is a good way to describe good THD numbers.
I would have to think for awhile how to get a good THD number with foul intermod numbers... Maybe if you fed in two noise signals outside the freq bandwidth that when nonlinear mixed gave a difference freq of 2 KHz that would sound horrible even if a pure sinewave input at 1K sounds awesome. It would take some work to screw up an amp this way but it could happen.
Anyway nothing says "tradeoff" like engineering and I wouldn't trade off a pretty basic core characteristic like THD for improved ... anything, except maybe power level. I'd rather hear something good than something a couple dB louder. Reporting good THD is valid in marketing as a way to tell that you did at least the very first homework problem... I agree totally with you that there are multiple steps beyond it, but there's no point in working on any of them if you can't pass the first simple THD test. (Edited to add, I missed the PERFECT analogy: Its like passing the UL Labs certification that it probably won't burn your house down. That's kinda required, and its also possible to aim a little higher)
Back in the day, I used to build Class A directly heated triode tube amps for hi-fi. These are poo-poo'd by the self-styled "scientific" hi-fi community for their high THD specs. But it's important to think about not only how much distortion is happening, but where the distortion is happening. In super-simple triode tube circuits with no negative feedback loops, THD is pretty much linear to the volume. For small signals - the detail in the mids and highs - distortion is effectively unmeasurable.
The mainstream A/B transistors + heavy negative feedback architecture has the benefit of low manufacturing cost (no need to match devices when you just feedback the differences out) and good specs. But where does the distortion happen? At the Class A/B crossover point, somewhere in the first watt. Until the amp hits maximum power and clips, the WORST distortion is in the first watt, where all the small signals live.
To my common sense and my ears, this explains how good-spec amps can sound very harsh and cold, while bad-spec amps can sound sweet and warm. It's not "euphonic distortion", as the pseudo-scientists claim. Rather, it's that the warm amp is actually distorting less where it actually matters.
The mainstream A/B transistors + heavy negative feedback architecture has the benefit of low manufacturing cost (no need to match devices when you just feedback the differences out) and good specs. But where does the distortion happen? At the Class A/B crossover point, somewhere in the first watt. Until the amp hits maximum power and clips, the WORST distortion is in the first watt, where all the small signals live.
To my common sense and my ears, this explains how good-spec amps can sound very harsh and cold, while bad-spec amps can sound sweet and warm. It's not "euphonic distortion", as the pseudo-scientists claim. Rather, it's that the warm amp is actually distorting less where it actually matters.
Thinking about this a bit more, I suspect the reason for the superb sonic reputation of a lot of inexpensive "Class T" digital amps is that they push the frequency-domain distortion problems into a different frequency. Digitally switching at far higher frequencies than audio and then modulating audio onto that signal is a pretty brilliant approach. You get the cost benefits of digital switching amps, without audio frequency domain artifacts from all the many kinds of low-level signal crud. The artifacts are there - they're just several octaves out of band for audio.
here is another interesting tale of home-made speakers, this fellow made some very large boxes and had very specific drivers he wanted but they were still inexpensive. He used active (powered as opposed to passive RLC network) crossovers. Also he built his own off-grid house with mini-hydro plant. the OP will probably find it interesting. I ended up reading every page on this fellows 90's style website.
http://ludens.cl/Electron/Speakers/speakers.html
http://ludens.cl/Electron/Speakers/speakers.html
> "While commercial musical equipment is usually of quite usable quality, commercial speakers unfortunately are not, unless you go to exotic and extremely expensive brands. The reason is simple: Good speakers, by law of physics, need to be large. There is no way around this basic fact."
Is this as true as it was in the 1990's?
A lot of people have high-end small speaker systems with branding such as 'Bose' on the front. Maybe they have got old and their ears have changed, but even if they once had big-box speakers due to the physics reasons, they have moved to the small speaker 5.1 things and it is now okay to do that. The sub-woofer doesn't have to be stereo either.
I don't know, but has new thinking fundamentally changed how hi-fi is done from the twin speaker stacks of old with lots of tweeters/woofers/crossovers to these new-fangled mini-5.1 things?
Is this as true as it was in the 1990's?
A lot of people have high-end small speaker systems with branding such as 'Bose' on the front. Maybe they have got old and their ears have changed, but even if they once had big-box speakers due to the physics reasons, they have moved to the small speaker 5.1 things and it is now okay to do that. The sub-woofer doesn't have to be stereo either.
I don't know, but has new thinking fundamentally changed how hi-fi is done from the twin speaker stacks of old with lots of tweeters/woofers/crossovers to these new-fangled mini-5.1 things?
Low frequency response needs size. If you're willing to cutoff at 200 Hz then little stuff will work. In my high school years I built a stereotypical mono subwoofer of the 2x4 sheet of plywood for front and back variety. Sounded pretty good, but could have been better.
A mantra thats repeated continuously, mostly by people selling mono subwoofers or uninterested in audio reproduction, is low freqs are non-directional.
Yet I go outside and listen to thunderstorms and passing unmuffled motorcycles and firearms and much bigger .mil weaponry and it sounds highly directional. I can point at the rumble of distant artillery as well as any other sound.
Surely if you build a directional subwoofer system and can only perceive a field, that'll work OK even if its an economic financial fail. But the other way around is an epic fail. So save money at the risk of sounding bad. Well, if the point is spending money to sound good, having an extra 3 dB of signal is never a loss...
Another puzzle is I know from experience that L-R and L+R sound different from FM subcarrier detection. Supposedly mono subwoofer people claim that magically only applies to higher freqs. I would think a single mono channel subwoofer would sound "better" fed off only L or R channel than some peculiar mix of unknown phase. The problem is which channel to connect to?
Phase relationships are a pretty big puzzle in audio once you get past simple response problems and simple distortion problems.
A mantra thats repeated continuously, mostly by people selling mono subwoofers or uninterested in audio reproduction, is low freqs are non-directional.
Yet I go outside and listen to thunderstorms and passing unmuffled motorcycles and firearms and much bigger .mil weaponry and it sounds highly directional. I can point at the rumble of distant artillery as well as any other sound.
Surely if you build a directional subwoofer system and can only perceive a field, that'll work OK even if its an economic financial fail. But the other way around is an epic fail. So save money at the risk of sounding bad. Well, if the point is spending money to sound good, having an extra 3 dB of signal is never a loss...
Another puzzle is I know from experience that L-R and L+R sound different from FM subcarrier detection. Supposedly mono subwoofer people claim that magically only applies to higher freqs. I would think a single mono channel subwoofer would sound "better" fed off only L or R channel than some peculiar mix of unknown phase. The problem is which channel to connect to?
Phase relationships are a pretty big puzzle in audio once you get past simple response problems and simple distortion problems.
All sound waves are directional, but the point made by acousticians is that in any enclosed space with dimensions smaller than the wavelength in question (56 feet for 20Hz), low frequencies are effectively non-directional because they fill the entire space (with nulls at various points). The wavelength of high frequencies means you can orient their direction in the room.
Of course you won't hear this outdoors because the sounds are not in an enclosed space.
Of course you won't hear this outdoors because the sounds are not in an enclosed space.
I'd suggest that the reason mini speakers are popular has to do with aesthetics since they are often paired with a television in a multipurpose room. And with the advent of 5.1, having five full range speakers, wiring, and a subwoofer in a small living room doesn't pass the aesthetic test.
Bose and other manufacturers have done a good job of developing tricks that fool undiscerning listeners into thinking their system matches the performance of a full range system. But there's no tricking out the physics of low frequencies. Baffles and complex tube resonators can have limited positive effects but they often cause problems in other areas.
That said, unless all you care about is sound quality, the aesthetics and performance of a Bose system can in many cases be very attractive.
Bose and other manufacturers have done a good job of developing tricks that fool undiscerning listeners into thinking their system matches the performance of a full range system. But there's no tricking out the physics of low frequencies. Baffles and complex tube resonators can have limited positive effects but they often cause problems in other areas.
That said, unless all you care about is sound quality, the aesthetics and performance of a Bose system can in many cases be very attractive.
This is only a box for speakers, I was expecting something more.
Ah, but the box is a big deal. I'm a DIY speaker builder, but for musical instrument rather than hi-fi use. The box is an integral part of the electromechanical system that determines the response (and to some extent power handling) of the speaker at low frequencies. The box may be a plain box whose volume is its main parameter, or may contain other structures such as resonant ports.
Most woofers are designed so they have to be in an appropriate box in order to be useful. Without access to the process for designing custom woofers, the DIY'er has at our disposal two main variables for tailoring low frequency response: Woofer choice from off the shelf models, and box design. And there are some tradeoffs to manage, such as low frequency response and box size, so that there's no ideal box design for all uses.
Most woofers are designed so they have to be in an appropriate box in order to be useful. Without access to the process for designing custom woofers, the DIY'er has at our disposal two main variables for tailoring low frequency response: Woofer choice from off the shelf models, and box design. And there are some tradeoffs to manage, such as low frequency response and box size, so that there's no ideal box design for all uses.
> musical instrument rather than hi-fi use
Me, too. Just when speaker design seemed to be a solved problem, with a small set of uniform solutions, up springs the concept of co-designing speakers and musical instruments.
What frequency range/instrument are you working with? And what architecture/horns/boxes/tubes/drivers?
Me, too. Just when speaker design seemed to be a solved problem, with a small set of uniform solutions, up springs the concept of co-designing speakers and musical instruments.
What frequency range/instrument are you working with? And what architecture/horns/boxes/tubes/drivers?
Sorry, I left town right after posting that. I'm a bassist, so it's 40 Hz up into the midrange, with not that much going on in the tweeter zone. So far my designs are just lightweight "pro audio" drivers in ported boxes. Nothing sophisticated, but I just want to be in control of how my speakers work.
Interestingly enough, I think that the electric bass involves a sort of de facto co-design, because the bass acquired its "classic tone" during a time when speakers were relatively low performance, i.e, having -3 dB points far above the lowest fundamental. To this day, speakers with that tone quality tend to be preferred by bassists, which is a fortuitous circumstance because it liberates us from dragging around huge boxes capable of actually reproducing that E fundamental at full strength.
Interestingly enough, I think that the electric bass involves a sort of de facto co-design, because the bass acquired its "classic tone" during a time when speakers were relatively low performance, i.e, having -3 dB points far above the lowest fundamental. To this day, speakers with that tone quality tend to be preferred by bassists, which is a fortuitous circumstance because it liberates us from dragging around huge boxes capable of actually reproducing that E fundamental at full strength.
Ah, DIY speakers! The general rule here is that DIY speakers will sound as good as commercial speakers that cost 4-5x as much. You can buy kits with pre-cut parts, so all you need to do is glue/clamp and build the crossovers.
Easy-to-build bookshelf speakers, the Overnight Sensations--$136 with free shipping: http://www.parts-express.com/overnight-sensations-mt-speaker...
And the Amiga towers are great for a living room, more towards $300 for the pair: http://www.diysoundgroup.com/speaker-kits/amiga-kit.html
More Amiga info: https://sites.google.com/site/undefinition/diy/amiga
I have built both, they're both really great at what they do. If I ever have the free time and money, I'd love to build some Statements: http://speakerdesignworks.com/Statements.html
Easy-to-build bookshelf speakers, the Overnight Sensations--$136 with free shipping: http://www.parts-express.com/overnight-sensations-mt-speaker...
And the Amiga towers are great for a living room, more towards $300 for the pair: http://www.diysoundgroup.com/speaker-kits/amiga-kit.html
More Amiga info: https://sites.google.com/site/undefinition/diy/amiga
I have built both, they're both really great at what they do. If I ever have the free time and money, I'd love to build some Statements: http://speakerdesignworks.com/Statements.html
Is that general rule pretty accurate? I've been contemplating buying an home speaker upgrade and pretty price adverse because I don't _need_ to upgrade. I am currently using Harman Kardon Soundsticks II w/ sub for my home audio and have no complaints -- kept this for 8 years really, so maybe I don't know what I'm missing. Are those 300 really ~ to $1200. If so, that sounds like a solid project!
I'd say so! Most of my information comes from a super-long 3000-post speaker thread on a private music site. I have auditioned a few high-end speakers in stores and would say that DIY holds its own very well.
Personally, I replaced an ~$800 pair of speakers with the Amigas, and they're vastly better in terms of clarity/resolution. I have a decent tube amplifier already.
Past that point I'm pretty sure room setup/room treatment starts to matter much more than hardware...
Personally, I replaced an ~$800 pair of speakers with the Amigas, and they're vastly better in terms of clarity/resolution. I have a decent tube amplifier already.
Past that point I'm pretty sure room setup/room treatment starts to matter much more than hardware...
Which tube amp do you have (or should I buy?). I'm in the market for one :-)
I have a Yaqin MC 10L: http://www.ebay.com/itm/YAQIN-MC-10L-Push-Pull-Integrated-St...
With aftermarket tubes: http://psvanetube.com/wordpress/purchase/shuguang-treasure-s...
The amp is super heavy (40+ lbs), so shipping is expensive.
I like it a lot--definitely changes the sound to something warmer. It's also a beautiful object, especially in the dark. The aftermarket tubes helped resolve bass, but are probably overkill (I used them as a reward to myself for crunch on a contract gig).
Note that tube amps have a lot of downsides--you can't leave them on 24/7, they make a lot of heat (so can't stack with other electronics), you need to tune voltage during the first few months of operation, only stereo output with minimal AV switching, etc...
With aftermarket tubes: http://psvanetube.com/wordpress/purchase/shuguang-treasure-s...
The amp is super heavy (40+ lbs), so shipping is expensive.
I like it a lot--definitely changes the sound to something warmer. It's also a beautiful object, especially in the dark. The aftermarket tubes helped resolve bass, but are probably overkill (I used them as a reward to myself for crunch on a contract gig).
Note that tube amps have a lot of downsides--you can't leave them on 24/7, they make a lot of heat (so can't stack with other electronics), you need to tune voltage during the first few months of operation, only stereo output with minimal AV switching, etc...
Thanks for the info!
I made some Overnight Sensations 6 months ago and they are great. The build process was really fun and the finished product is much better that what I could have bought (though if you factor in time, they are actually pretty expensive).
Agreed on time! I think I spent ~5 hours on the Overnight Sensations and maybe 10 hours on the Amigas. Personally, I really enjoyed having a not-at-the-computer hobby I could put time into every night.
But yeah, if you're just looking for a cheap set of speakers, and don't care about the actual DIY angle, making your own might be feel like a frustrating time sink...
But yeah, if you're just looking for a cheap set of speakers, and don't care about the actual DIY angle, making your own might be feel like a frustrating time sink...
Years ago, a boss of mine used to build speakers from scratch. He played for me a recording of a symphony where there was a sound of rolling thunder along with the tinkle of glass. It was flawless and amazing to hear.
Does anyone know if this is a graduate level course? Seems like working with JBL engineers and getting mentored by TH is something that would draw a big crowd.
If you want to go really nuts, take a look at the Elsinore by Joe Rasmussen: http://www.customanalogue.com/elsinore/elsinore_index.htm
He does a great job of designing a crossover and phase-inverting the tweeter to get an excellent step response. beat mentions that this is something most speaker manufacturers fail to account for.
It's about as good as you're going to get for a DIY design and a whole associated design guide.
He does a great job of designing a crossover and phase-inverting the tweeter to get an excellent step response. beat mentions that this is something most speaker manufacturers fail to account for.
It's about as good as you're going to get for a DIY design and a whole associated design guide.
anyone who pays more than 200 on Chinese speakers at bestbuy are the bane of my existence. they drive everything up. and then publish tons of unscientific reviews and technobabble to justify their silly spending.
I once had a prof who designed his own speakers and built them out of concrete. They were massive, full-range beasts that were flat down to 20 Hz. (in the right room). As it turns out, concrete is surprisingly good speaker material, aside from the near total lack or portability. Some crazy (and crazy rich) audiophile bought them for $50K. Selling slabs of concrete for $50K a pop sounds like a great business model, but there is a severely limited number of people willing to pay that much for speakers, and the speakers apparently took hundreds of hours of tweaking to work "properly" anyways.
"In the right room" is important. Anyone who spent $50k on loudspeakers ought already to have spent an equal amount on room geometry and materials. In fact above a fairly modest amount (a few thousand bucks, maybe) most people will get superior results from changing the room, rather than spending more on the equipment.
Yay! Audio knowledge! I've met so-called "geeks" who will look at you funny if you start talking about "frequency response" -- but they'll talk your ear off if you remind them about the frequency domain and Fourier Transforms. Back in the late 20th century, just about everyone who was tech savvy seemed to know some basics about sound. Nowadays, I wonder if the whole Monster Cable/coathanger thing has made some people filter out everything sounding like audio knowledge as "woo." Not all of it is. A lot of it is physics.
Back in the 80's, designing and building your own speakers was a suitable project for high school students. Still is.
Back in the 80's, designing and building your own speakers was a suitable project for high school students. Still is.
Maybe for CS "geeks" but for those of us who came up through the EE ranks linear systems is our bread and butter.
So how did he design them? What tools does one use to do this? I have a form factor in mind for some speakers that I'd like to build for my off-road truck [1]. I have a certain look and mounting style in mind and I haven't seen anything like it. I just don't know where to start with the design, though.
[1] https://flic.kr/p/o1xmJ8
[1] https://flic.kr/p/o1xmJ8
In addition to what jzwinck recommended, I'd also recommend the Loudspeaker Design Cookbook [0] and the Master Handbook of Acoustics [1]
If you're an engineer that's comfortable with differential calculus, I'd recommend the grandaddy of them all: Acoustics by Beranek [2] (I'm actually linking to Acoustics: Sound Fields and Transducers which is an updated version of Beranek's original Acoustics cowritten with Tim Mellow)
[0] http://www.amazon.com/Loudspeaker-Design-Cookbook-Vance-Dick...
[1] http://www.amazon.com/Master-Handbook-Acoustics-Alton-Everes...
[2] http://www.amazon.com/Acoustics-Transducers-Leo-L-Beranek/dp...
If you're an engineer that's comfortable with differential calculus, I'd recommend the grandaddy of them all: Acoustics by Beranek [2] (I'm actually linking to Acoustics: Sound Fields and Transducers which is an updated version of Beranek's original Acoustics cowritten with Tim Mellow)
[0] http://www.amazon.com/Loudspeaker-Design-Cookbook-Vance-Dick...
[1] http://www.amazon.com/Master-Handbook-Acoustics-Alton-Everes...
[2] http://www.amazon.com/Acoustics-Transducers-Leo-L-Beranek/dp...
I made some speakers when I was in high school. The tools I used were a table saw, a whole bunch of long clamps, a screwdriver, and a hand drill. But most important, this book: http://www.amazon.com/Building-Speaker-Systems-2nd-Edition/d... . If you buy it used now you will find it hilarious how they describe using computer software to analyze speaker systems, but no matter: you can stand on the shoulders of giants and design your own boxes without any software at all.
The "D'Appolito array" is covered in that book--a design employed in many store-bought speakers where two mid-woofers flank a tweeter at a specific distance to avoid some of the time alignment concerns raised here. This is a good candidate if you want to build smallish, narrow speakers for home. In the car it usually comes down to "where is there enough room for the drivers I want?"
I think the book also discusses various dual-driver arrangements for subwoofers, which is another interesting area where you can use twin drivers to eliminate undesirable effects. If you put that together with the D'Appolito design in a single cabinet, you will have something like what Infinity used to sell for $1000 each...but doing it well won't save you much money because good drivers are expensive.
The "D'Appolito array" is covered in that book--a design employed in many store-bought speakers where two mid-woofers flank a tweeter at a specific distance to avoid some of the time alignment concerns raised here. This is a good candidate if you want to build smallish, narrow speakers for home. In the car it usually comes down to "where is there enough room for the drivers I want?"
I think the book also discusses various dual-driver arrangements for subwoofers, which is another interesting area where you can use twin drivers to eliminate undesirable effects. If you put that together with the D'Appolito design in a single cabinet, you will have something like what Infinity used to sell for $1000 each...but doing it well won't save you much money because good drivers are expensive.
I have degree in computer science but I owe a large part of what I understand about physics and electronics to my speaker building hobby. I highly recommend getting into the physics of sound. It’s actually pretty simple and will teach you how waves behave in general.
http://www.cs.helsinki.fi/u/ljlukkar/labsub/
I’m currently working on a Arduino based pre amp that hosts a rest api for remote controlling: http://tinypic.com/r/15yvj2g/8 http://tinypic.com/r/11vmhld/8 http://tinypic.com/r/jrzfk5/8
http://www.cs.helsinki.fi/u/ljlukkar/labsub/
I’m currently working on a Arduino based pre amp that hosts a rest api for remote controlling: http://tinypic.com/r/15yvj2g/8 http://tinypic.com/r/11vmhld/8 http://tinypic.com/r/jrzfk5/8
So how do you get into the physics of sound?
I don't think I'll be building speakers anytime soon though, but I'm still very much interested in the details of psychoacoustics and sound reproduction.
I don't think I'll be building speakers anytime soon though, but I'm still very much interested in the details of psychoacoustics and sound reproduction.
Start by reading this:
http://www.amazon.com/Acoustical-Foundations-Music-Second-Ed...
http://www.amazon.com/Acoustical-Foundations-Music-Second-Ed...
I'm very interested in the Arduino based pre amp. Do you have a page with your design that I can study? I was thinking about maybe integrating a Lightspeed Attenuator.
Most of all, I'd like the pre amp to automatically turn on the power amp (currently a Gainclone) when a signal starts coming in from the connected Airport Express.
http://diyaudioprojects.com/Solid/DIY-Lightspeed-Passive-Att...
Most of all, I'd like the pre amp to automatically turn on the power amp (currently a Gainclone) when a signal starts coming in from the connected Airport Express.
http://diyaudioprojects.com/Solid/DIY-Lightspeed-Passive-Att...
http://www.amb.org/audio/alpha10/
Here's another arduino-based pre-amp. This one includes relay-based stepped attenuators and input selectors. The pcbs are all available as well as the schematics in case you just want to use it as a base for your own project.
Here's another arduino-based pre-amp. This one includes relay-based stepped attenuators and input selectors. The pcbs are all available as well as the schematics in case you just want to use it as a base for your own project.
consider digital crossover from minidsp. I've made a pair of powered 2-ways with a minidsp/miniamp combo in each.
Those aren't homemade speakers, they're homemade enclosures. Disappointed as I was expecting something more substantial than "I made a box".
DIY speakers as a hobby is mostly about enclosures and crossover networks. It's quite rare that people would build their own speakers drivers (some planar speakers being an exception).
Where it's rewarding is taking available drivers and building a full speaker around them -- usually optimizing for performance vs cost. It's difficult and expensive to build really high quality loudspeakers. Add markup to that and the retail price of a well engineered speaker will quickly go into 5 digits.
The speakers in my living room are DIY (though they don't really look "DIY" as far as that might carry negative connotations) and they're an excellent value. They were also fun to build. In no way was I disappointed afterwards because I had not, say, wound the voice coils myself.
Where it's rewarding is taking available drivers and building a full speaker around them -- usually optimizing for performance vs cost. It's difficult and expensive to build really high quality loudspeakers. Add markup to that and the retail price of a well engineered speaker will quickly go into 5 digits.
The speakers in my living room are DIY (though they don't really look "DIY" as far as that might carry negative connotations) and they're an excellent value. They were also fun to build. In no way was I disappointed afterwards because I had not, say, wound the voice coils myself.
The box is a huge factor in making them sound good.
For a brief time, I had a pair of speakers on my desk made from old PC case speakers that I salvaged and just put on stands made from blocks of wood with a hole in them. I liked the look, and the sound was alright, but rather weak and tinny. Then one day I decided to build a box around them, and the difference was night and day - much louder sound with significantly more bass.
For a brief time, I had a pair of speakers on my desk made from old PC case speakers that I salvaged and just put on stands made from blocks of wood with a hole in them. I liked the look, and the sound was alright, but rather weak and tinny. Then one day I decided to build a box around them, and the difference was night and day - much louder sound with significantly more bass.
This might sound harsher than intended, but given how the performance of a speaker is driven by the interaction of the enclosure with the driver parameters its kind of like saying a saxophone is just an enclosure for a reed. Or a car engine carburetor is just an enclosure for the air that connects to an engine. The acoustics of the enclosure dominate the performance of the overall speaker, especially at the low end freqs.
There is a big difference between just making a box, making a box that looks nice, and making a box that cooperates with the specs of the driver to make a good speaker.
You might be surprised how awful the specs are for a bare driver hanging by its wires in the air without an enclosure. It is very much like the analogy of a musical instrument reed.
There is a big difference between just making a box, making a box that looks nice, and making a box that cooperates with the specs of the driver to make a good speaker.
You might be surprised how awful the specs are for a bare driver hanging by its wires in the air without an enclosure. It is very much like the analogy of a musical instrument reed.
Agreed. I think there's a lot to be learned from building a driver, if only for the powerful experience of realizing that there's nothing magical about it. Just a magnet and a coil of wire. It's the equivalent a CS guy designing a rudimentary processor: it won't be necessary be good enough to beat out commercial stuff, but it sure does convince you that the thing you take for granted really can be done with just transistors/magnets and wire.
I for one would have loved to do this kind of activity as a kid: it's a pretty simple concept that puts a whole lot of power in your hands and exposes interesting questions. It looks like Bose is doing something in this space at kids science camps [0]. If you can acquire/make an amp and a strobe light to replace their "blue box", there's a whole host of kid-friendly activities on the site to do with kids centered around making hand-made, origami paper drivers.
[0] http://build.bose.com/
I for one would have loved to do this kind of activity as a kid: it's a pretty simple concept that puts a whole lot of power in your hands and exposes interesting questions. It looks like Bose is doing something in this space at kids science camps [0]. If you can acquire/make an amp and a strobe light to replace their "blue box", there's a whole host of kid-friendly activities on the site to do with kids centered around making hand-made, origami paper drivers.
[0] http://build.bose.com/
http://www.theregister.co.uk/2014/07/02/feature_the_future_l... - has an interesting perspective on speaker design and the human auditory system.
A friend of mine created an online app that helps calculating Loudspeaker Enclosures. The app is completely free, no registration necessary.
http://micka.de/org/en/index.php
Hope that someone finds this useful.
http://micka.de/org/en/index.php
Hope that someone finds this useful.
i read several claims that you can buy components and blueprints and build yourself speakers which would be much better than what you could buy for the price. this sounds like a business opportunity to me. anybody knows why nobody is selling good speakers for less?
Generally speaking, if you thought of something obvious, search the internet, somebody is already doing it. For example - http://www.htd.com/ - and godzillion other.
Because hours of effort, marketing, etc aren't accounted for in the price of your DIY.
The hi-fi speaker business is a highly competitive market. The invisible hand already drives prices to about where they can go.
The hi-fi speaker business is a highly competitive market. The invisible hand already drives prices to about where they can go.
If anyone is thinking to build their own cabinets - I would suggest checking out
https://www.parts-express.com/cat/speaker-components/4
I have built a few speakers from scratch, including line arrays using them as my source. They are kind of like the mono price of speaker parts.
To my ears, the best and most musical sounding speakers I've heard have time-aligned drivers and very simple crossovers. Tannoy, Spica, Vandersteen, and other such designs are clearer and less fatiguing. I'm a musician and have recorded numerous albums, and those speakers are the ones that match what I'm used to hearing the best.
The fundamental problem is that we work on what we can measure. It's very easy to measure frequency response. It's very hard to measure phase alignment. So we fix what we can measure. If you want to see serious map-over-territory thinking, look at THD specs for amplifiers. It's super-easy to measure THD - just isolate harmonics of a sine wave a 1khz. Unfortunately, this has approximately zero to do with music, unless your idea of "music" is static sine waves. Recorded music has a 20-30db dynamic range (less in the case of modern pop) and covers ten octaves. Dynamic recovery behavior, intermodulation distortion, stuff like this is what gives amps their distinctive sounds - but it's nearly impossible to measure! So they sell what looks good on paper... THD. Sigh.