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I'll state this... I'd be willing to bet that I could predict the results of someone in an a/b/x listening test where they are subjected to a subwoofer amplifier with a damping factor of 50 and a damping factor of 100. Out of 100 people, 98 of them wouldn't be able to tell which amplifier they were listening to based on damping factor beyond any statistical significance of guessing. The other two outliers may be just that dang good OR that dang lucky. Regardless, chances are anyone reading this thread will be in the 98 people group who won't be able to tell, yet most will think they are the golden ear two without being able to tell yet alone repeat the results.

Now let's take this further with a car amplifier, where the damping factor spec used to be cheated by being measured at the circuit board, versus at the speaker leads, yet alone the speaker itself. Yeah, good luck with that spec making a huge difference in SQ when you don't even know where it is measured.

Back to my original comment when it comes to cone control, a properly designed and implemented servo will beat damping factor 7 days a week and twice on Sunday! It should also reduce subwoofer induced distortion from the cone movement itself. I was told that the Velodyne car audio servo subwoofer was one of the best, but they failed to take one variable into consideration with the cone position sensor.... The movement of the vehicle itself. It was great for an SQ competition, but in some instances, results could vary once the vehicle was in motion. Oddly, this was vehicle dependent as I knew two different people who used this setup and one claimed it was fine with the vehicle still or in motion whereas the other one said it only worked in his trailer queen SQ vehicle and driving made the sub vary...

Which brings me to my next point. We are talking about CAR AUDIO here, which is generally the absolute worst reproduction environment that anyone could ever want when it comes to audio... At least modern day digital processing is making it better for multi-listening positions and imaging, to some degree. Good luck getting your anechoic chamber response in a vehicle.
No one, including me, stated a vehicle was an echoic chamber. The assertion that testing in an anechoic environment to begin with, is somehow irrelevant or unsubstantiated to achieve solid results and the effects of beginning with the best design you can afford is beyond rational thought, and nothing more than rhetoric over issues you don't understand. and to play the subjective card of a/b listening tests is just as irrational. It's just that simple.
 

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Is there a link to the testing Altec did? I'd like to see what the results were.
The company was sold in 1998, and the archives were not released. In fact most of it was destroyed. And that's sad too... Some sales info and cabinet designs are out there in the public domain, but no testing results were ever allowed out, and would be considered trade secrets.
 

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No one, including me, stated a vehicle was an echoic chamber. The assertion that testing in an anechoic environment to begin with, is somehow irrelevant or unsubstantiated to achieve solid results and the effects of beginning with the best design you can afford is beyond rational thought, and nothing more than rhetoric over issues you don't understand. and to play the subjective card of a/b listening tests is just as irrational. It's just that simple.
So you are telling me if one can't tell a difference in a listening test, then it doesn't matter? I've seen plenty of high end manufacturers butt-hurt over cheaper amps performing better than their SQriffic examples throughout the years. They even try to rationalize that a listening test isn't long enough to tell a true difference or come up with other ways to invalidate the test.

But I'll digress, spend the money on what you want to spend your money on. If one thinks that damping factor of 500 is what it takes to achieve SQ, even when there is no industry standard for where said damping factor is measured, then by all means, spend away.

I'm just saying there are other places to look if something sounds wonky besides damping factor.

Finally, audio is my hobby and I'm just a nerd with some calibrated measuring equipment and a computerized RTA that allows me to send signal and measure on the same loop so I can apply an equalization curve that sounds good to me, and 99% of everyone else who listens to my system from the driver's seat. But hey, if you think damping factor is where the SQ difference is based on nominal impedance without taking box rise into consideration, be my guest! That's the beauty of the First Amendment and internet forums. :p
 

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So you are telling me if one can't tell a difference in a listening test, then it doesn't matter? I've seen plenty of high end manufacturers butt-hurt over cheaper amps performing better than their SQriffic examples throughout the years. They even try to rationalize that a listening test isn't long enough to tell a true difference or come up with other ways to invalidate the test.

But I'll digress, spend the money on what you want to spend your money on. If one thinks that damping factor of 500 is what it takes to achieve SQ, even when there is no industry standard for where said damping factor is measured, then by all means, spend away.

I'm just saying there are other places to look if something sounds wonky besides damping factor.

Finally, audio is my hobby and I'm just a nerd with some calibrated measuring equipment and a computerized RTA that allows me to send signal and measure on the same loop so I can apply an equalization curve that sounds good to me, and 99% of everyone else who listens to my system from the driver's seat. But hey, if you think damping factor is where the SQ difference is based on nominal impedance without taking box rise into consideration, be my guest! That's the beauty of the First Amendment and internet forums. :p
When you try to throw enough crap on the wall, hoping some of will stick, you end up where you are. Out of one side of your argument, damping factor doesn't play any part, then out of the other side, you argue servo's will outperform DF that which you said was irrelevant. You can't have it both ways. And to try to introduce subjective listening tests, you only attempt to muddy the water with subjective results that no one can pin down. Why? Because it's all subjective to the listener, and not empirical data. This is why manufacturers test in controlled environments. I can hear it now, "don't use measuring equipment, especially calibrated equipment, because, yeah, that sounds like a volt..." Pure bovine scatology.

I've come to conclude you're simply wanting to argue for no other reason than to argue. Go save face with someone else.
 

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When you try to throw enough crap on the wall, hoping some of will stick, you end up where you are. Out of one side of your argument, damping factor doesn't play any part, then out of the other side, you argue servo's will outperform DF that which you said was irrelevant. You can't have it both ways. And to try to introduce subjective listening tests, you only attempt to muddy the water with subjective results that no one can pin down. Why? Because it's all subjective to the listener, and not empirical data. This is why manufacturers test in controlled environments. I can hear it now, "don't use measuring equipment, especially calibrated equipment, because, yeah, that sounds like a volt..." Pure bovine scatology.

I've come to conclude you're simply wanting to argue for no other reason than to argue. Go save face with someone else.
I'm pretty sure I haven't contradicted myself. I said if you wanted cone control, a server was where it was at. Only problem, good luck getting that in a car as no one makes them these days. OTOH, for the home front, both Velodyne and Rythmik are viable choices and well regarded.

When it comes to the worst reproduction environment known to man for audio, I'm of the school of thought that damping factor above the audible threshold where no one can tell a difference is a waste of time, money, and effort. If it makes a difference to YOU to spend money on something that has an advertised damping factor of 1,000 at the circuit board, by all means, SPEND YOUR MONEY. I'm saying look elsewhere! Besides, there is a law of diminishing returns where an exponential price increase in equipment may result in single digit to no percentage of satisfaction increase with swapping out gear.
 

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I'm pretty sure I haven't contradicted myself. I said if you wanted cone control, a server was where it was at. Only problem, good luck getting that in a car as no one makes them these days. OTOH, for the home front, both Velodyne and Rythmik are viable choices and well regarded.

When it comes to the worst reproduction environment known to man for audio, I'm of the school of thought that damping factor above the audible threshold where no one can tell a difference is a waste of time, money, and effort. If it makes a difference to YOU to spend money on something that has an advertised damping factor of 1,000 at the circuit board, by all means, SPEND YOUR MONEY. I'm saying look elsewhere! Besides, there is a law of diminishing returns where an exponential price increase in equipment may result in single digit to no percentage of satisfaction increase with swapping out gear.
Again, you have missed the entirety of the conversation by the bias you seem to be unwilling to recognize. And that bias is based from inexperience. You're presenting extremes to attempt to prove a point that is not rational. I don't need 100 people to come and listen, I can use a mic and capture the results and see with my own eyes. Don't try to blame me because you poorly designed your system, that's on you.

Concerning the home front, Yamaha has been working for a while on adding a second smaller coil to the LF driver and using it as a reference voltage (a mic is simply a speaker in reverse) to feed signal comparison against the output and using DSP to modify the output signal, much like current noise-cancelling headphones use.

But outside of that type of technology, you can certainly achieve decent control by properly matching the compliance of the driver to the cabinet design, keeping the load (speaker's VC impedance) of the amp in a region that keeps the DF as far above >100 as possible, keeping leads to the LF driver as short as possible, (preferably only a couple of feet) and 10 gauge or larger, not because of current, but voltage drop. Properly implementing a sub design isn't that hard, no matter the environment. And just because you are placing this in a vehicle, doesn't negate the very same engineering principles used in any other environment. And since Class D doesn't perform to the DF levels of thousands like can be achieved by Class A/B, then attempting to load it @ 2 or 1 ohm can only do you more harm than good on DF. This is just simple design considerations. Get real.
 

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Concerning the home front, Yamaha has been working for a while on adding a second smaller coil to the LF driver and using it as a reference voltage (a mic is simply a speaker in reverse) to feed signal comparison against the output and using DSP to modify the output signal, much like current noise-cancelling headphones use.
Any idea if they're using a FxLMS algorithm? I'm considering tinkering with a custom DSP to achieve that in-car and I'm trying to think about how I'd do it.
 

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...

But outside of that type of technology, you can certainly achieve decent control by properly matching the compliance of the driver to the cabinet design, keeping the load (speaker's VC impedance) of the amp in a region that keeps the DF as far above >100 as possible, keeping leads to the LF driver as short as possible, (preferably only a couple of feet) and 10 gauge or larger, not because of current, but voltage drop. Properly implementing a sub design isn't that hard, no matter the environment. And just because you are placing this in a vehicle, doesn't negate the very same engineering principles used in any other environment. And since Class D doesn't perform to the DF levels of thousands like can be achieved by Class A/B, then attempting to load it @ 2 or 1 ohm can only do you more harm than good on DF. This is just simple design considerations. Get real.
How does the low DF manifest itself on the sound compared to a high DF?
 

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How does the low DF manifest itself on the sound compared to a high DF?
It has already been stated a few times in this thread. Please see previous posts.

Interestingly enough, Greg Timbers, the highly regarded Chief Engineer of JBL fame of speakers like the Everest, as well as almost every famous JBL design, especially studio monitors, since the 70's was asked;

Anechoic or listening? That is, where do measurements and listening fall in design? (Value, importance, role…)

"This is a loaded question. I am going to answer it as I believe is correct. All designs require and deserve full Anechoic and other types of measurements. The cost, size or intended market for the device should not change the measurements taken. It doesn't matter how expensive a loudspeaker is, it should always be the absolutely best effort within the constraints agreed upon by cost, performance, appearance, etc. In many respects, cheap speakers are actually more challenging to do correctly. Once you know what your parts are capable of, you can work to achieve the highest level of performance possible within the guidelines."
 

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Any idea if they're using a FxLMS algorithm? I'm considering tinkering with a custom DSP to achieve that in-car and I'm trying to think about how I'd do it.
I don't have first hand knowledge of what those boys over in Japan are cooking up, however, the YST technology is currently available in the home sub market.
 

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That's why jbl is mythical God like status in the recording, venue, 2 channel, and even car with the Gti.



How does the low DF manifest itself on the sound compared to a high DF?
It has already been stated a few times in this thread. Please see previous posts.

Interestingly enough, Greg Timbers, the highly regarded Chief Engineer of JBL fame of speakers like the Everest, as well as almost every famous JBL design, especially studio monitors, since the 70's was asked;

Anechoic or listening? That is, where do measurements and listening fall in design? (Value, importance, role…)

"This is a loaded question. I am going to answer it as I believe is correct. All designs require and deserve full Anechoic and other types of measurements. The cost, size or intended market for the device should not change the measurements taken. It doesn't matter how expensive a loudspeaker is, it should always be the absolutely best effort within the constraints agreed upon by cost, performance, appearance, etc. In many respects, cheap speakers are actually more challenging to do correctly. Once you know what your parts are capable of, you can work to achieve the highest level of performance possible within the guidelines."
 

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I don't have first hand knowledge of what those boys over in Japan are cooking up, however, the YST technology is currently available in the home sub market.
Gotcha, thanks
 

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So you are telling me if one can't tell a difference in a listening test, then it doesn't matter? I've seen plenty of high end manufacturers butt-hurt over cheaper amps performing better than their SQriffic examples throughout the years. They even try to rationalize that a listening test isn't long enough to tell a true difference or come up with other ways to invalidate the test.

But I'll digress, spend the money on what you want to spend your money on. If one thinks that damping factor of 500 is what it takes to achieve SQ, even when there is no industry standard for where said damping factor is measured, then by all means, spend away.

I'm just saying there are other places to look if something sounds wonky besides damping factor.

Finally, audio is my hobby and I'm just a nerd with some calibrated measuring equipment and a computerized RTA that allows me to send signal and measure on the same loop so I can apply an equalization curve that sounds good to me, and 99% of everyone else who listens to my system from the driver's seat. But hey, if you think damping factor is where the SQ difference is based on nominal impedance without taking box rise into consideration, be my guest! That's the beauty of the First Amendment and internet forums. :p
I quoted the much acclaimed and infinitely respected Greg Timbers, the highly regarded Chief Engineer of JBL, and he stated this concerning listening tests as it relates to results on design;

"I have no use for blind and double blind listening tests the way Harman implements them. Sound systems and their environments are very complicated. No speaker is even close to sounding "real" so personal opinion is always a major consideration. Most blind tests are based on a series of assumptions that enable the test to be easy or practical to implement. Unfortunately, these assumptions often invalidate or color the results because they cover up or accentuate aspects of the loudspeaker design."

I certainly don't stand alone in the audio industry when it comes to the BS of trying to introduce A/B listening tests in its subjective results as the criteria of testing results.
 
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