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post #31 of 55 Old 01-29-2016, 07:09 PM
 
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Originally Posted by ronny31 View Post
Perhaps, but at what point does the extra distortion produced by a speaker get drowned out by the distortion in the original instrument and become irrelevant no matter how much quantifiably "better" a speaker is than another?
Never. Instruments do not have harmonic distortion. Their harmonic structure is part and parcel of their signature sound. It's the main component of what makes a piano sound different from an oboe, or Sinatra different from Streisand.
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post #32 of 55 Old 01-29-2016, 07:24 PM - Thread Starter
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Yes, but, how much force does it take to accelerate an object with zero mass to infinite velocity?
Infinitely small amount of force. But even then an infinitely small force acting on zero mass equals infinite velocity. Same as infinite divided by infinite isn't 1 but infinite. It made mathematicians insane for a reason, but its quite straightforward. I say this allthough off-topic because someone out there might want to know that there's actually papers on using infinite numbers in mathematics, and someone might want to look that up. Or at least watch the documentary.

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The original instrument's sound contains zero distortion. Distortion is defined as a modification of an original. You can't have that if what you have IS the original.
it may contain zero "distortion" as we speak of it now, but the original instrument has sound other than the clear tone itself that you would get for example with synthesizers. Its an odd shaped object with reflections and corners and phase changes, not to mention frequency response changing with the slightest move of the person playing. The noise of movement as well, the finger taps, the breathing, the reflection of the figure playing and the obstruction of the mic(s) themselves. We could go on for as long as time exists and still come up with more.
All this, drowns out the distortion added by the speakers at some point. What point?
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post #33 of 55 Old 01-29-2016, 07:38 PM
 
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it may contain zero "distortion" as we speak of it now, but the original instrument has sound other than the clear tone itself that you would get for example with synthesizers. Its an odd shaped object with reflections and corners and phase changes, not to mention frequency response changing with the slightest move of the person playing. The noise of movement as well, the finger taps, the breathing, the reflection of the figure playing and the obstruction of the mic(s) themselves.
That's not distortion. It's the natural sound of the instrument. As already pointed out distortion is when the system, be it the AVR, amp, speaker or whatever doesn't reproduce that exactly.
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post #34 of 55 Old 01-29-2016, 07:46 PM
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Originally Posted by ronny31 View Post

it may contain zero "distortion" as we speak of it now, but the original instrument has sound other than the clear tone itself that you would get for example with synthesizers. Its an odd shaped object with reflections and corners and phase changes, not to mention frequency response changing with the slightest move of the person playing. The noise of movement as well, the finger taps, the breathing, the reflection of the figure playing and the obstruction of the mic(s) themselves. We could go on for as long as time exists and still come up with more.
All this, drowns out the distortion added by the speakers at some point. What point?
Wrong again, Babbage breath!

"Distortion is the alteration of the original shape (or other characteristic) of something, such as an object, image, sound or waveform. "

The sound emanating from an instrument of any kind is the original , and therefore, cannot, by definition, be distorted, as it remains unaltered, rich harmonic content and all.

By your definition, every single sound other than a sine wave is distorted. Wrong. We can easily measure distortion in what originated as a perfect ramp or triangular waveform, but after distortion no longer is a perfect ramp or triangle. And yet, the spectrum of such a waveform is riddled with odd-order harmonics.
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post #35 of 55 Old 01-30-2016, 09:37 AM - Thread Starter
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Originally Posted by jaddie View Post
Wrong again, Babbage breath!

"Distortion is the alteration of the original shape (or other characteristic) of something, such as an object, image, sound or waveform. "

The sound emanating from an instrument of any kind is the original , and therefore, cannot, by definition, be distorted, as it remains unaltered, rich harmonic content and all.

By your definition, every single sound other than a sine wave is distorted. Wrong. We can easily measure distortion in what originated as a perfect ramp or triangular waveform, but after distortion no longer is a perfect ramp or triangle. And yet, the spectrum of such a waveform is riddled with odd-order harmonics.
No that is not my definition that's a strawman definition.

I agree with your definition of distortion, but that's not what I'm referring to. Why the h*** can't you just humor me with the perfectly reasonable assumption that some of the stuff recorded when instruments are playing, is going to drown out the distortion improvements in the speakers? Stop focusing on some minor thing which just derails the discussion all because you want to make a strawman argument.

To move it forwards, here are some issues raised if we just humor the hypothesis: Is it easier to hear differences in distortion figures on speakers if we listen to a single instrument being played, or a single voice. Or is it easier if we listen to a symphony with two orchestras and a 50 person choir?

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post #36 of 55 Old 01-30-2016, 10:04 AM
 
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Why the h*** can't you just humor me with the perfectly reasonable assumption that some of the stuff recorded when instruments are playing, is going to drown out the distortion improvements in the speakers?
Because the assumption is incorrect. I do agree though that some recordings are so inherently bad that nothing could make them any worse.
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post #37 of 55 Old 01-30-2016, 03:15 PM
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Originally Posted by ronny31 View Post
To move it forwards, here are some issues raised if we just humor the hypothesis: Is it easier to hear differences in distortion figures on speakers if we listen to a single instrument being played, or a single voice. Or is it easier if we listen to a symphony with two orchestras and a 50 person choir?
The audibility of distortion is always a multi-dimensional problem encompassing distortion type, degree, acoustic level, distortion product spectral distribution, etc. There's no single answer to any of the above mentioned stimuli, however vague they may be.

Except, I believe distortion is more audible with a 50 voice choir than a 49 voice choir. Unless voice #50 has an upper respiratory problem.

Does that humor the hypothesis?
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post #38 of 55 Old 02-02-2016, 11:32 AM
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Originally Posted by ronny31 View Post



it may contain zero "distortion" as we speak of it now, but the original instrument has sound other than the clear tone itself that you would get for example with synthesizers. Its an odd shaped object with reflections and corners and phase changes, not to mention frequency response changing with the slightest move of the person playing. The noise of movement as well, the finger taps, the breathing, the reflection of the figure playing and the obstruction of the mic(s) themselves. We could go on for as long as time exists and still come up with more.
All this, drowns out the distortion added by the speakers at some point. What point?
no natural instrument produces a single frequency,k afaik, After the very important initial impulse, it is the various harmonics that define, for human listeners, whether an instrument is a classical flautist, a singer, a piano or a soloed Hendrix guitar track. Those harmonics just cannot be thought of as distortion (although the Hendrix guitar sound includes plenty of distortion from the amp and/or other devices between guitar and amp. It's still the sound. The mic will pick up all those harmonics (probably not accurately, which is why people pay thousands of dollars for old Neumanns) and the mic's output gets recorded. Maybe the recorder (especially in analog days) adds distortion of its own. But for our purposes the recording itself is the "pure sound" no matter the distortions on the way to the recording.

Harder to hear speaker distortion on top of Hendrix's (or pick your post or pre Hendrix guitar player - - Muddy Waters if you wish) intentionally distorted sound. Much easier with that flautist playing solo, or a piano, or to some degree a violin( although the string instruments begin to exhibit distortion-like harmonics when the player really digs in).

There is no answer to when it becomes audible. Not really, anyway. It's controlled by the context. AFAIK, the old old research indicates that with purish tones, for the vast majority of human listeners, distortion becomes just audible around 1%. OTOH, I've read that guitarists will identify an amp as clean (i.e undistorted) when it's at 10% distortion. And many musical instrument amplification devices are specified (without actually saying it because they don't have to) at max power at 10%, FWIW
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post #39 of 55 Old 02-02-2016, 11:53 AM
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I think that the essential point here is that whatever imperfections are embedded in a recording are simply there, for better or worse. A speaker with minimal distortion will play those recordings in all their glory (or otherwise). But once a speaker adds its own distortion to whatever is being played back, there is no reason to believe that the speaker's distortion will enhance the recording. So, whether the imperfections resulting from too close miking, or extraneous noise or distortion in the recording or mixing studio, or from whatever source, are perceived to overwhelm the distortion produced by a bad speaker, or vice versa, is sort of irrelevant. A good speaker can deliberately have a slightly more forward mid-range, or a slightly more rolled-off treble, or whatever, and still sound good to someone. But, I would think that the greater the inherent distortion in a speaker, the less it would qualify for your definition of high-end.

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post #40 of 55 Old 02-02-2016, 01:18 PM
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Originally Posted by ronny31 View Post
Is it easier to hear differences in distortion figures on speakers if we listen to a single instrument being played, or a single voice. Or is it easier if we listen to a symphony with two orchestras and a 50 person choir?
Insidious products of non-linear behavior in loudspeakers are intermodulation effects produced when multiple voices/instruments are present at significant loudness. Which are often responsible for a hard to describe "dulling" of the overall reproduced sound.

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Reading this has given me a headache. I can't decide if my headache is an original creation or simply a replay of a prior headache with added distortion.
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post #42 of 55 Old 02-02-2016, 05:52 PM
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Would anyone like to take a gander at what design features make a speaker driver and subsequently a speaker itself "high end" in audio quality.
Easy. At least one extra zero at the end of the price tag than it deserves.
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post #43 of 55 Old 02-02-2016, 08:44 PM
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Single driver:
- smooth and flat frequency response within and reasonably beyond the intended range of use
- low distortion motor
- low cone stored energy
- well behaved cone breakup ideally well outside the intended range of use
- low mechanical noise and near symmetric backwave
- volume displacement enough for required spl target but in as small a physical package as possibile to facilitate meeting final speaker design requirements
- good thermal handling and heat dissipation to minimize power compression
- hopefully, all that with reasonable efficiency and power handling so it can be put to use

Final speaker:
- smooth and flat on axis frequency response
- smooth and flat horizontal power response
- horizontal polar response shape suited to room (degree of damping and competency of treatment implementation)
- well behaved vertical response (good - symmetric lobes with broad on axis lobe, better - minimal lobing)
- minimized baffle diffraction effects
- backwave appropriately handled (set free, utilized in resonant reinforcement, or otherwise well absorbed)
- lack of cabinet resonances
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post #44 of 55 Old 02-03-2016, 07:55 AM
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Originally Posted by PrimeTime View Post
Insidious products of non-linear behavior in loudspeakers are intermodulation effects produced when multiple voices/instruments are present at significant loudness. Which are often responsible for a hard to describe "dulling" of the overall reproduced sound.
maybe we just hear differently. I am unaware of any distortion that removes higher harmonics (which would make the sound duller, to me). Certainly I've owned guitar speakers that will produce a sub harmonic when an already distorted sound is fed into them and , say , the player is producing a non harmonic pair of notes (like taking a bent note slowly down against the initial tone on the adjacent string). weird stuff happens. But it doesn't make the sound duller.

Distortion, whether it's im distortion or harmonic distortion, does not remove the higher frequencies that make things sound bright. Most of even IM distortion is higher harmonics, which to me sounds brighter, not duller. If your speakers are distorting in a way that makes hings sound what I would call dull, there's something wrong with them . . . .
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Originally Posted by JHAz View Post
maybe we just hear differently. I am unaware of any distortion that removes higher harmonics (which would make the sound duller, to me). Certainly I've owned guitar speakers that will produce a sub harmonic when an already distorted sound is fed into them and , say , the player is producing a non harmonic pair of notes (like taking a bent note slowly down against the initial tone on the adjacent string). weird stuff happens. But it doesn't make the sound duller.

Distortion, whether it's im distortion or harmonic distortion, does not remove the higher frequencies that make things sound bright. Most of even IM distortion is higher harmonics, which to me sounds brighter, not duller. If your speakers are distorting in a way that makes hings sound what I would call dull, there's something wrong with them . . . .

I would agree with you here. I could see poor off-axis response, or incorrect toe-in, causing a dulling in the sound. And perhaps an over-treated room (with respect to mid and high frequencies) could produce that effect, but I don't see it as an inherent product of a speaker playing multiple instruments, any more than it would be in a live performance.

Mid-range and high-frequency distortion sounds bright or harsh to me. I will say, though, that bass distortion in a room can produce a muffled, or duller sound for the mid-range. A revelation for me was how much bass distortion I had in my room, and how much employing broadband bass traps improved the clarity of my mid-range. So, something like that might conceivably be a factor in producing a dull sound, where the frequencies of some instruments are masked by the low frequency distortion in the room.

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Another measure is what we could call ear fatigue. Whether it be a FR imbalance, or an excess of distortion, or both, how loud you can go before ear fatigue sets in is a type of gauge. As I have refined my own system, one of the things that jumps out is that these days, the louder it is, the better it sounds to me. This wasn't always the case though. While I have always enjoyed music played fairly loud (90-95SPLdb at the LP), the threshold of where it sounded best wasnt always in the 90-95db area.

In times past, when I had little to no room treatment and less capable speakers, as the volume level increased, certain elements or areas of the sound spectrum would get harsh or cluttered sounding before others.

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post #47 of 55 Old 02-03-2016, 10:41 AM
 
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Another measure is what we could call ear fatigue. Whether it be a FR imbalance, or an excess of distortion, or both, how loud you can go before ear fatigue sets in is a type of gauge.
High level harmonic distortion increases the spectral density in the midrange, where hearing is most sensitive. The phenomenon that we can listen to music at much higher levels without discomfort when it's 'clean' compared to 'dirty' has been documented for just about as long as we've been listening to recordings. It's also well known that what sounds bad also is what can hurt us. That's one of the reasons why 'A' weighting is specified for noise exposure levels and duration. It filters out what's least likely to cause damage, focusing on what's most likely to cause damage.
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post #48 of 55 Old 02-04-2016, 02:19 AM - Thread Starter
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Originally Posted by JHAz View Post
no natural instrument produces a single frequency,k afaik, After the very important initial impulse, it is the various harmonics that define, for human listeners, whether an instrument is a classical flautist, a singer, a piano or a soloed Hendrix guitar track. Those harmonics just cannot be thought of as distortion (although the Hendrix guitar sound includes plenty of distortion from the amp and/or other devices between guitar and amp. It's still the sound.
It is interesting that you bring up electric guitars. It brings me onto live music sound reinforcement. The PA speakers and the drivers they use are made to be as loud as possible given the limitation of financials, physics and available room. Which, end up checking these boxes:

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Originally Posted by Bigus View Post
Single driver:
- smooth and flat frequency response within and reasonably beyond the intended range of use
- low distortion motor
- low cone stored energy
- well behaved cone breakup ideally well outside the intended range of use
- low mechanical noise and near symmetric backwave
- volume displacement enough for required spl target but in as small a physical package as possibile to facilitate meeting final speaker design requirements
- good thermal handling and heat dissipation to minimize power compression
- hopefully, all that with reasonable efficiency and power handling so it can be put to use

Final speaker:
- smooth and flat on axis frequency response
- smooth and flat horizontal power response
- horizontal polar response shape suited to room (degree of damping and competency of treatment implementation)
- well behaved vertical response (good - symmetric lobes with broad on axis lobe, better - minimal lobing)
- minimized baffle diffraction effects
- backwave appropriately handled (set free, utilized in resonant reinforcement, or otherwise well absorbed)
- lack of cabinet resonances
Because, it seems the features that allow loudness, necessitates not having these flaws. Can't play loud if the voice coil melts before it is loud, can't have loud if it has lots of moving mass relative to its magnet strength and the amount of voice-coil in the magnet-gap, can't play loud if it distorts a lot due to weak suspension and cone, can't play loud if it only plays a few frequencies loud and the rest low, can't play loud if the cabinet moves too much (cabinet movement is energy that isn't sound).

Granted, PA enclosures have a larger size limit than home-grade stuff, but the db goal for home-grade stuff is lower. If we downscale good PA drivers for the output requirements of home-grade stuff, would the end product be high-end quality sound? The same PA driver design only with half the scale, would that be high end sound quality speakers at the proportionally lower volume output? Or are home-grade speakers we deem high quality, of lower/higher quality than they would be if only downsized versions of their best possible PA counterpart?

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maybe we just hear differently. I am unaware of any distortion that removes higher harmonics (which would make the sound duller, to me). Certainly I've owned guitar speakers that will produce a sub harmonic when an already distorted sound is fed into them and , say , the player is producing a non harmonic pair of notes (like taking a bent note slowly down against the initial tone on the adjacent string). weird stuff happens. But it doesn't make the sound duller.

Distortion, whether it's im distortion or harmonic distortion, does not remove the higher frequencies that make things sound bright. Most of even IM distortion is higher harmonics, which to me sounds brighter, not duller. If your speakers are distorting in a way that makes hings sound what I would call dull, there's something wrong with them . . . .
He spoke of the dulling of details in the sound as volume is increased. Just try it. Take a piece you know well and compare very loud and normal db levels (very loud being at the extreme of what your system can do, not what you deem loud).
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post #49 of 55 Old 02-05-2016, 01:21 PM
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Originally Posted by ronny31 View Post
Because, it seems the features that allow loudness, necessitates not having these flaws. Can't play loud if the voice coil melts before it is loud, can't have loud if it has lots of moving mass relative to its magnet strength and the amount of voice-coil in the magnet-gap, can't play loud if it distorts a lot due to weak suspension and cone, can't play loud if it only plays a few frequencies loud and the rest low, can't play loud if the cabinet moves too much (cabinet movement is energy that isn't sound).
Well, some, but not all are complimentary.

One of the quickest ways to increased SPL is increased cone surface area. This often wreaks havoc cone stored energy, cone breakup, polar shape and power response, it separates drivers physically leading to increased vertical lobing, it increases baffle width and typically increases baffle diffraction artifacts from adjacent smaller high frequency drivers...

Lighter cones are good for increased efficiency which lowers power compression, can reduce BL requirements which sometimes enables lower distortion motor design, and typically extends frequency response. On the other hand, it makes cone breakup harder to control. Increasing cone mass can help some of those, but often increases stored energy...

Long throw smaller diameter drivers are a solution to many of the above, but then are harder and more expensive to maintain low motor distortion, low power compression, low intermodulation distortion, low mechanical noise...

You can increase number of drivers, but then have to deal with interdriver lobing artifacts. You can minimize those by maintaining symmetry and using the smallest diameter drivers possible, but then...

Well, you get the idea.

Nothing about speaker design is easy. Nothing about driver design is easy either... and there really isn't one "best" driver, or even one "best" tweeter, midrange, woofer etc. There are only "best" options within a given budget and especially given your choice of tradeoffs briefly mentioned above. There is more than one way to skin a cat. Geddes and Linkwitz designs in many ways couldn't be more different, yet start from the same objectives and end up with more characteristics shared with one another than with many other speakers.

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Originally Posted by Bigus View Post
Well, some, but not all are complimentary.

One of the quickest ways to increased SPL is increased cone surface area. This often wreaks havoc cone stored energy, cone breakup, polar shape and power response, it separates drivers physically leading to increased vertical lobing, it increases baffle width and typically increases baffle diffraction artifacts from adjacent smaller high frequency drivers...

Lighter cones are good for increased efficiency which lowers power compression, can reduce BL requirements which sometimes enables lower distortion motor design, and typically extends frequency response. On the other hand, it makes cone breakup harder to control. Increasing cone mass can help some of those, but often increases stored energy...

Long throw smaller diameter drivers are a solution to many of the above, but then are harder and more expensive to maintain low motor distortion, low power compression, low intermodulation distortion, low mechanical noise...

You can increase number of drivers, but then have to deal with interdriver lobing artifacts. You can minimize those by maintaining symmetry and using the smallest diameter drivers possible, but then...

Well, you get the idea.

Nothing about speaker design is easy. Nothing about driver design is easy either... and there really isn't one "best" driver, or even one "best" tweeter, midrange, woofer etc. There are only "best" options within a given budget and especially given your choice of tradeoffs briefly mentioned above. There is more than one way to skin a cat. Geddes and Linkwitz designs in many ways couldn't be more different, yet start from the same objectives and end up with more characteristics shared with one another than with many other speakers.
+1 ^ This was a very intelligent post.
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post #51 of 55 Old 02-10-2016, 12:37 PM
 
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This was a very intelligent post.
Yes, but it can be succinctly summed up in the #1 rule of loudspeaker design: There's no such thing as a free lunch.
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post #52 of 55 Old 02-10-2016, 06:32 PM
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Hey, I had a free lunch today! Well... the department paid for it, but free for me is good enough and all that really matters anyway.
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post #53 of 55 Old 02-11-2016, 02:05 AM - Thread Starter
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and there really isn't one "best" driver, or even one "best" tweeter, midrange, woofer etc. There are only "best" options within a given budget and especially given your choice of tradeoffs briefly mentioned above.
Well yeah, but surely if we point the goal at best sound quality, then we will find a group of design compromises that are superior? Probably a set of optimal compromises along the scale of db output capacity, since you can probably get the same sound quality for cheaper if the output amount is smaller.
The same way we find that all the Formula 1 teams make cars that look similar; That happens to be the best way to go fast around a track 50-100 times with minimal fuel stops, to our current level of knowledge. Then the cheaper Formula classes represent cheaper ways to get round quick.

So, no costs barred, lets say it has to be 10" diameter. Then the optimal SQ design would maybe be (random big numbers here) 1000oz+ neodynium magnet, with a solid carbon fiber epoxy spider, coil and cone, with aluminium coil wires for weight savings. The coil would be lets say 7" diameter and 20mm coil winding depth inside a 30mm magnet gap, so its entirely inside the magnet gap up to 5mm xmax, allowing reasonably good sensitivity (with the 1000oz magnet) in spite of insane spider stiffness. As well as an even force application per watt during the stroke. Note that if you had a smaller diameter voice coil you would have that much less voice coil inside the magnet gap hence each watt would do less.
The surround would be quite large in diameter but made out of a thin carbon fiber composite, so it allows in and out movement of the cone yet preventing any other movement. The spider and surround thickness would be adjusted to be such that the insane magnet and voice coil combo has about 90db 1w/m output. Perhaps the spider would be so stiff that the resonance frequency is above the frequency area that the driver is used in, so that the weight of the cone never oscillates in tune with its natural frequency.
interesting to theorize like this. Because it appears good expensive home-grade drivers are on the track to this. Often deeper basket and magnet structure than the diameter of the driver. And often magnet size on par with 18" PA drivers that can put out 125-130db continuously. But they have voice coils like 1-2" sometimes a bit more, and often something like 10mm magnet gap and 30-50mm winding depth, making 10-20mm xmax. So there's much much less voice coil in the magnet gap, so most of each watt powers voice coil that isn't in the magnet gap, all to just get extra xmax at the cost of smaller woofer size. yes, sure, they can have stiffer woofer and have less breakup and distortion that way, but then they need weaker spider than they otherwise could have because they still need 85-90db 1w/m efficiency.
I would love to read the mind of the high SQ driver engineers.

Now, what shape would be best? I don't see much variation in that.
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post #54 of 55 Old 02-11-2016, 10:54 AM
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Lighter cones are good for increased efficiency which lowers power compression, can reduce BL requirements which sometimes enables lower distortion motor design, and typically extends frequency response.
Reducing magnet size is more consistent with economy of design than performance. Increasing gap flux density (Teslas) increases sensitivity and linearity (i.e., less distortion for a given output).

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So, no costs barred, lets say it has to be 10" diameter..
Overlooking the awkwardly undersized cone diameter, your design speculations here are only (remotely) relevant to an infrasonic radiator. Which only has application in an enclosed pressure-chamber environment found in some reinforced home theater rooms -- a rather niche application. Infrasonic radiators are rarely effective in free-field (cinema, outdoor) environments where they can be overwhelmed by louder, more efficient bass systems.
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post #55 of 55 Old 02-12-2016, 09:18 PM
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Reducing magnet size is more consistent with economy of design than performance. Increasing gap flux density (Teslas) increases sensitivity and linearity (i.e., less distortion for a given output).
Was thinking perhaps it would allow underhung vs overhung but freely admit driver design ain't my thing.
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