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Who makes the lowest distortion speaker drivers
Who makes the lowest distortion speaker drivers
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Old 10th November 2017, 10:31 AM   #661
bentoronto is offline bentoronto  Canada
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Who makes the lowest distortion speaker drivers
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Originally Posted by gedlee View Post
All audio testing based on the time/frequency relationships of the FFT are band limited. AT the low end it is limited by the length of the time sample and at the high end it is limited by the sample rate. We cannot know anything about the system outside of these limitations
Once again, thanks for bringing your knowledge to bear. But back to my question that you discussed in posts 632-635.

I'm still living in the age of "brass instruments" and in fact do want to look at impulse behaviour as seen with a real-life mic, not a virtual reality sim.

While I don't have access to any of those perfect impulses (or infinitely powerful amps to deliver them or cleaning tools to scape the woofer cone off the opposite wall), I do wonder what the mic pick-up will look like using a pretty-good impulse.

BTW, in addition to being puzzled about putting a wide-band signal into a band-limited DUT, also seems peculiar to use a DC-to-light signal which is all positive since that also isn't something audio systems do.

B.
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Old 10th November 2017, 11:08 AM   #662
33Polkhigh is online now 33Polkhigh  United States
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Originally Posted by wesayso View Post
It's just a different presentation of the same data. Learn what each tells you and how they are all related and you can get more out of them in terms of what you hear.
If we say so then I'll just have to accept it, but obviously one shows change over time.
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Old 10th November 2017, 12:34 PM   #663
lowmass is offline lowmass  United States
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Originally Posted by bentoronto View Post
In days of yore (1970's about when silicone glue appeared, if I recall), people used the same silicone glue to coat surrounds but thinned it first (with vinegar??). I think mostly to improve the imperviousness of accordion cloth surrounds. Parts Express now sells some new-fangled paint goo for coating.

As others have said, hard to guess the effect. I stupidly did some coating not long ago on a 15-inch sub surround and it raised the resonance from about 22 to about 50 Hz. Also, surrounds are developed to have ideal spring performance and well-behaved damping. But new layers of coating, esp silicone glue, are likely to behave differently and so introduce distortion. Of course some folks may like the way the newly added higher-freq harmonics sound.

B.
Yes I would have expected the silicone coating to upset the higher frequency perf. This was a cheap 15 inch poly cone with a surround that was a vinyl based material I believe. Basically a material that had a fair amount of hysteresis, I assume because the driver was designed to be used up to about 1khz . I however was using it below 300 in one system and as a sub in another. The material had a noticeably slow return to position when flexed. It was also very temperature sensitive.

The silicone coating gave the surround a much more spring like character as well as stiffening and raising res to about 40.
Basically I thought it was a test of two opposite extreems in suspension mechanical properties and their effect on bass perf. BUT I wonder how much if any it was this or how much it may have been simply the added control due to increased resonant point?

Years before this I was playing around modifying cones to build an open baffle woofer. I was trying to build something similar to the drivers used in the Carver dipole speaker. At first the motors were modified to increase Q. BUT what was really surprising was eventually I modified the suspension to a very high Q springy system. I cut out the spider completely and replaced it with two threads crossed at 90 deg through the VC former. These threads were tension ed and tuned on springs and a screw. This is where I noticed again a marked change in the sound of the driver. It suddenly had a "bouncy fast dynamic" quality in the bass. Sorry for the description but I just dont know any other way to describe it. The effect could be heard even at very low volumes hold driver close to ear.
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Old 10th November 2017, 05:16 PM   #664
1audiohack is offline 1audiohack  United States
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Quote:
Originally Posted by bentoronto View Post
Once again, thanks for bringing your knowledge to bear. But back to my question that you discussed in posts 632-635.

I'm still living in the age of "brass instruments" and in fact do want to look at impulse behaviour as seen with a real-life mic, not a virtual reality sim.
How are you going to view it then? An O scope on the mic?

Quote:
Originally Posted by bentoronto View Post
While I don't have access to any of those perfect impulses (or infinitely powerful amps to deliver them or cleaning tools to scape the woofer cone off the opposite wall), I do wonder what the mic pick-up will look like using a pretty-good impulse.
So put a mic in front of a speaker and whack it with the biggest charged capacitor you have and have a look, somehow.

Quote:
Originally Posted by bentoronto View Post
BTW, in addition to being puzzled about putting a wide-band signal into a band-limited DUT, also seems peculiar to use a DC-to-light signal which is all positive since that also isn't something audio systems do.
But that's what a theoretical impulse is, DC to light, all frequency in zero time. If you want to use an "real impulse" that's what you would get. Why would you want to? If you are looking for a valid transducer measurement, using a signal that drives the DUT into nonlinearity makes no sense.

Sweeping a driver well beyond it's normal passband (in both directions) can yield information of value and constructing an impulse view from that data is not a useless VR sim.

What are you really driving at? Honestly you confuse me.
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Old 10th November 2017, 06:55 PM   #665
planet10 is offline planet10  Canada
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Who makes the lowest distortion speaker drivers
Quote:
Originally Posted by 33Polkhigh View Post
...and this appears in the CSD…
Resonances are much easier to see and to compare — the appearance of the Q of the ringing is the same across the frequency range — if the CSD uses periods on the time axis instead of sec. A well behaved driver will have equal spacing of the curves as the driver rings down.

dave
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Old 11th November 2017, 12:32 AM   #666
soongsc is offline soongsc  Taiwan
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Quote:
Originally Posted by planet10 View Post
Resonances are much easier to see and to compare — the appearance of the Q of the ringing is the same across the frequency range — if the CSD uses periods on the time axis instead of sec. A well behaved driver will have equal spacing of the curves as the driver rings down.



dave
Actually that was what I was suggesting for SoundEasy to implement.
When drivers of same sensitivity and similar bandwidth are compared, the driver with a longer decay will usually be perceived as louder.
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Old 11th November 2017, 02:10 AM   #667
33Polkhigh is online now 33Polkhigh  United States
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Large domes

Here's a comparison of a few large dome tweeters. The expensive seas one has what seems to be a much better csd plot, much tighter and uniform vs the others. This difference isn't apparent in the fr.

I have to say though the nonlinear distortion of the big seas dome doesn't look that stellar, not bad but not stellar either.
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Old 11th November 2017, 09:22 AM   #668
wesayso is online now wesayso  Netherlands
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I'd suggest looking a bit closer. Surely you can see the FR anomalies where ringing occurs with most of these drivers.
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Old 11th November 2017, 09:28 AM   #669
soongsc is offline soongsc  Taiwan
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You can see some of the larger effects in the FR plots, but some can decay faster, slower, and some are really hidden in the lower levels which do not show up in the FR unless you really scale in. These differences can cause different sonic qualities and are much easier identified in the CSD.
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Old 11th November 2017, 09:35 AM   #670
vacuphile is offline vacuphile  Netherlands
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Quote:
Originally Posted by Boden View Post
Hello Vac,

Would you care to explain what is meant by:

"There are perfectly flat speakers with horrible FR"

Basically you are challenging the Fourier Transform with the full version of your statement - including the part of good decay-above.

Now that is quite a position.

Care to clarify & substantiate the above? I am bit puzzled to put it mildly.

Eelco
Hi Eelco, you are perfectly right, I started out with one sentence and then combined it with another so what it reads here indeed is nonsense. The 'perfectly flat' should have been deleted. But I didn't.

The point is: you can have a flat speaker FR-wise with troublesome energy storage issues and the other way around.
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