Is there really such a thing as a FAST driver?

Bob Reynolds · « **on:** 20 Dec 2006, 05:07 pm »

You typically see the comment applied to woofers and subwoofers. Is it real? If so, what would determine speed differences?

Thanks.

JoshK · « **Reply #1 on:** 20 Dec 2006, 05:35 pm »

My opinion is that the subjective quality of "fast" is related to a number of physical phenomena such as enclosure and driver electrical energy storage and the Q of the system, particularly in room and the existence of lack there-of of large room modes.

miklorsmith · « **Reply #2 on:** 20 Dec 2006, 06:02 pm »

I think subs are most prone to sounding "slow", so it is particularly noteworthy when one actually sounds fast.

This term is purely subjective, though physical properties are surely responsible.

I think of speed as one of the characteristics of a speaker, though DACs certainly can sound slower or less dynamic. Alone, speed is related to transient risetime. I find planar and ribbon speakers to be extremely fast but without the body and tone that a good wideranger can provide.

In some cases, speed can refer to dynamic shading where the tiniest shifts slide lithely from stop to stop. Some speakers hint at the ability while others present it front and center.

JLM · « **Reply #3 on:** 20 Dec 2006, 08:50 pm »

A heavy driver is slower than a lighter one.

A driver with a long Xmax would be slower than a larger driver (of the same moving weight) that can displace the same amount of air.

A compression (horn loaded) driver would be faster (but typically have colorations).

Marbles · « **Reply #4 on:** 20 Dec 2006, 09:00 pm »

This is a FAST driver....Danica Patrick

Bob Reynolds · « **Reply #5 on:** 20 Dec 2006, 10:56 pm »

Quote from: JLM on 20 Dec 2006, 08:50 pm

A heavy driver is slower than a lighter one.

That makes sense, but can't the motor assembly be scaled to compensate for the additional mass?

Does anyone know what a typical mass difference would be between various cone materials for say a 6.5" driver? Are we talking grams, 10s of grams?

Quote

A driver with a long Xmax would be slower than a larger driver (of the same moving weight) that can displace the same amount of air.

Slower in the sense of being less responsive to changing signals?

Is this an argument against smaller woofers with longer travel versus larger woofers with shorter travel?

BrassEar · « **Reply #6 on:** 20 Dec 2006, 11:22 pm »

You really need to read:
The TenBiggest Lies in Audio

http://theaudiocritic.com/downloads/article_1.pdf

JoshK · « **Reply #7 on:** 20 Dec 2006, 11:51 pm »

Quote from: BrassEar on 20 Dec 2006, 11:22 pm

You really need to read:
The TenBiggest Lies in Audio

http://theaudiocritic.com/downloads/article_1.pdf

Half that article is complete and utter crap and if the writer had any experience or ears they'd know such.

miklorsmith · « **Reply #8 on:** 20 Dec 2006, 11:52 pm »

Only half?

JoshK · « **Reply #9 on:** 20 Dec 2006, 11:54 pm »

Quote from: miklorsmith on 20 Dec 2006, 11:52 pm

Only half?

I didn't read it in great detail, but there is some truth too. I think that is how the writer conjures credibility by stating some truths and some hopeful wishes (lies of his own, in sort).

PaulHilgeman · « **Reply #10 on:** 21 Dec 2006, 12:04 am »

Quote

Does anyone know what a typical mass difference would be between various cone materials for say a 6.5" driver? Are we talking grams, 10s of grams?

Most 6.5" drivers range from about the lightest that I have seen of 8g or so, up to about 28g or so.

-Paul

Rob Babcock · « **Reply #11 on:** 21 Dec 2006, 12:06 am »

I think Pete Azcel has some standing in the audio press. He perhaps overstates his case, but I think there's some truth to what he says. I really like when he asks "what special insight do you gain by not matching levels and peeking at the name tag?"

miklorsmith · « **Reply #12 on:** 21 Dec 2006, 12:14 am »

Let's see -

1. Cables don't matter - maybe they do, maybe they don't. By anybody's measure this is one guy's opinion. Considering the rest of the claims, not an opinion I'm wont to value either.

2. Tubes are inherently inferior. Says you.

3. Digital's just fine - True, if you read theory and disregard your own ears.

4. ABX Testing Works - Not for me or any audioheads I know who have tried it. Let's not rehash this here. If you adhere to this philosophy, no part of your system except speakers need ever cost over $500.

5. Feedback is OK - I can agree with this, though there are no-feedback amps that are very nice.

6. Burn-in is a nonfactor - See [1.], above.

7. Biwiring is bogus - no experience with this, thus no opinion.

8. Power Conditioners are bogus - Little experience, but if you have switch-mode power supplies in the system, some filtration to the other gear seems smart.

9. CD Treatments are bogus - I don't have sufficient experience with these either.

10. Golden ears lord their expertise over the commoners - I haven't had this experience with anybody I've ever listened with. For that matter, even the Stereophile guys are more down-to-earth than this article suggests, and I find them more ivory-tower than most.

My basic problem with this article is that it pushes one of my hot buttons - Overblown rhetoric cast as fact, intended to reinforce a position. Calling people idiophiles for thinking differently and stupid for pursuing other paths is used to goad readers into believing what the author thinks. What I see here is a bunch of opinion based on half-baked theory which does not match my experience or that of many ears I trust.

Hey, where was the reference to driver speed BTW?

Canyoneagle · « **Reply #13 on:** 21 Dec 2006, 12:38 am »

Hey, where was the reference to driver speed BTW?

EXACTLY.
The reference to that article has NOTHING to do with this topic, unless there is an implied application of the (unrelated) topics in the article to this discussion.

Personally, I certainly feel that there are physical/mechanical attributes of drivers that contribute to (or detract from) what can be characterized as "fast". Driver material, mass, surround composition (stiffness, etc), driver excursion, magnet/motor capability, crossover characteristics, etc. all contribute to how the incoming electrical current is dealt with.

As far as the article is concerned, well, that is DEFINITELY one to post to fight club! (along with a binary 100% for or 100% against assertion)

That article had as much relevance as a political rant.

On with the show........

warmly,
Michael

Rob Babcock · « **Reply #14 on:** 21 Dec 2006, 01:00 am »

Well, I say a really fast woofer would be a tweeter.

Canyoneagle · « **Reply #15 on:** 21 Dec 2006, 01:02 am »

Yep, that's what I've got with my 8" hemp single drivers!!!!

heh heh heh heh heh

Warmly,
Michael

Bob Reynolds · « **Reply #16 on:** 21 Dec 2006, 04:02 am »

Quote from: BrassEar on 20 Dec 2006, 11:22 pm

You really need to read:
The TenBiggest Lies in Audio

http://theaudiocritic.com/downloads/article_1.pdf

Thanks, I've read it several times. As I've stated in this forum before, I'm a huge fan of The Audio Critic and reading all the back issues earlier this year was quite educational. I know that Peter has made comments regarding the speed of speakers in his magazine more than once, but he didn't provide any background information as I recall.

I'm not interested in starting a debate over Peter and his magazine. So those with differing views, please just let it pass.

Bob Reynolds · « **Reply #17 on:** 21 Dec 2006, 04:05 am »

Quote from: PaulHilgeman on 21 Dec 2006, 12:04 am

Quote
Does anyone know what a typical mass difference would be between various cone materials for say a 6.5" driver? Are we talking grams, 10s of grams?

Most 6.5" drivers range from about the lightest that I have seen of 8g or so, up to about 28g or so.

-Paul

Thanks, Paul. So can the motor assembly compensate for a 20g difference? If so, are there any negatives of doing so?

Canyoneagle · « **Reply #18 on:** 21 Dec 2006, 04:31 am »

Correct me if I'm off base here, but the additional driver mass would require more motor capability/control (assuming the same excursion), which would translate to (what could be percieved as) a penalty of higher power requirements?
Now, that is purely a rational deduction.
I'm as curious a Bob here. Is there an impact of such a situation on the sound?
If I could venture a guess, I would assume that the additional control of the driver (coupled with the additional mass of the driver) would result in what may be characterized as 'authority'.

Any thoughts?

Warmly,
Michael

warnerwh · « **Reply #19 on:** 21 Dec 2006, 04:50 am »

You often hear of planars, ribbons and electrostatics being labeled as fast. The transient response is superior to a cones due to little moving mass. It's a tiny fraction of what a cone driver uses. The mass of a cone can be ten or more times higher than a ribbon or planar. The planars on my speakers weigh 1.5 grams. Compared to a cone plus of course it's voice coil it's a small fraction of the equivalent cone.

Be sure to get All the moving weight when making calculations, there's more moving mass there than just the cone.