A/B vs Class D for Subwoofer SQ

[DidUHearThat? 10+ year member]

http://www.tom-morrow-land.com/tests/ampchall/index.htm

Richard Clark $10,000 Amplifier Challenge FAQ by Tom Morrow

Written 6/2006

The Richard Clark Amp Challenge is a listening test intended to show that as long as a modern audio amplifier is operated within its linear range (below clipping), the differences between amps are inaudible to the human ear. Because thousands of people have taken the test, the test is significant to the audiophile debate over audibility of amplifier differences. This document was written to summarize what the test is, and answer common questions about the test. Richard Clark was not involved in writing this document.

The challenge

Richard Clark is an audio professional. Like many audiophiles, he originally believed the magazines and marketing materials that different amplifier topologies and components colored the sound in unique, clearly audible ways. He later did experiments to quantify and qualify these effects, and was surprised to find them inaudible when volume and other factors were matched.

His challenge is an offer of $10,000 of his own money to anyone who could identify which of two amplifiers was which, by listening only, under a set of rules that he conceived to make sure they both measure “good enough” and are set up the same. Reports are that thousands of people have taken the test, and none has passed the test. Nobody has been able to show an audible difference between two amps under the test rules.

...

Do the results indicate I should buy the cheapest amp?

No. You should buy the best amplifier for your purpose. Some of the factors to consider are: reliability, build quality, cooling performance, flexibility, quality of mechanical connections, reputation of manufacturer, special features, size, weight, aesthetics, and cost. Buying the cheapest amplifier will likely get you an unreliable amplifier that is difficult to use and might not have the needed features. The only factor that this test indicates you can ignore is sound quality below clipping.

If you have a choice between a well built reliable low cost amp, and an expensive amplifier that isn't reliable but has a better reputation for sound quality, it can be inferred from this test that you would get more sound for your money by choosing the former.

 

[DidUHearThat? 10+ year member]

Is there one sentence that can describe what the test is designed to show? When compared evenly, the sonic differences between amplifiers operated below clipping are below the audible threshold of human hearing.

This is how these threads usually end.

 

[PaulD 10+ year member]

the distortion and other colorations of speakers are easily an order of magnitude higher than any amp, so who really cares.

 

[rc10mike 10+ year member]

IF someone has the ability to identify a difference in sound betweeen class A/B and class D, then they have never been able to prove that ability in a scientifically valid test.

But once you identify the qualities of an amplifier that attribute to "differences in sound", you will see that amplifier class is not one of them.

Well then maybe they need to test more people

 

[FoxPro5 5,000+ posts]

Well then maybe they need to test more people

LOL, RC has so much statistical power...it's not even funny. If you're that guy, take your $100 or whatever it costs....and your amps....and go for it. //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

Keep in mind no one is saying it's the end all be all, but the guy is not putting up a lot of cash if he thinks the odds might be in the participant's favor......even a little.

 

[rc10mike 10+ year member]

Somebody PLEASE show me in writing the latest A/B vs D sub amp test! Not the one from 2000.

 

[rc10mike 10+ year member]

LOL, RC has so much statistical power...it's not even funny. If you're that guy, take your $100 or whatever it costs....and your amps....and go for it. //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif
Keep in mind no one is saying it's the end all be all, but the guy is not putting up a lot of cash if he thinks the odds might be in the participant's favor......even a little.

So you never answered my question. Are you saying EVERY human alive has the same hearing and memory power?

 

[FoxPro5 5,000+ posts]

So you never answered my question. Are you saying EVERY human alive has the same hearing and memory power?

Well I thought I did but here goes again. We (like scientists and stuff that study it) know a lot about what humans can and cannot hear and the relative thresholds that define this aspect of sensory perception. Right? Perhaps we don't know everything. In fact, probably not. So, in this sense, you're probably correct: not EVERY human alive has the same hearing and memory power.

If your hearing is better and you know how to listen and can recall acute changes over time, gather your amps and take the test. The odds are stacked against you, but hey who knows? //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

In the mean time, practice with some A/B comparator software or take the Klippel distortion test and see how good you are. I've done it a bunch of times and almost got down below 1% THD on my computer speakers. I suppose if you really wanted to beat RC's statistical power, you could try to match his test protocol by running your own numbers.

At least then, you'd have some confidence in beating random chance - because you DO have a 50/50 shot at the correct answer, which DOES NOT mean you can actually hear that well, honestly....you're just a good guesser. Maybe a good guesser can collect $10k, but I reallllllly doubt it because it's designed to eliminate that over succesive trials. RC is a smart dude.

 

[cleansoundzz 10+ year member]

I think people when comparing AB vs. D speak more about the older amps circa 2000 and older. At those times with the technology the differences are more apparent. With technology catching up or caught up the differences between class AB vs. D are almost indistinguishable by ear. If Richard Clark would have offered that test in 1997-2000, he would have been bankrupt. In 2006, the technology was way better.

Again these scientific tests are for today's amps more or less not the "old school" amps.

 

[IDSkoT 5,000+ posts]

http://www.buwaldahybrids.com/phpBB3/viewtopic.php?f=26&t=4087

Holy Giant-Trophy, Batman!

 

[DEdwards 10+ year member]

Holy Giant-Trophy, Batman!

Thank you

Here is the press release done on me following Finals

http://blog.sounddomain.com/gadget/2008/11/dave-edwards-of.html

 

[mcsoul 10+ year member]

I think people when comparing AB vs. D speak more about the older amps circa 2000 and older. At those times with the technology the differences are more apparent. With technology catching up or caught up the differences between class AB vs. D are almost indistinguishable by ear. If Richard Clark would have offered that test in 1997-2000, he would have been bankrupt. In 2006, the technology was way better.
Again these scientific tests are for today's amps more or less not the "old school" amps.

The latest full range class D's are no cheaper than class A/B.

The power efficiency savings is minimal at best on a 4x100 amp.

The latest class D sub amps are more than competitive, they own the market

right now.

 

[gunz4me 10+ year member]

The latest full range class D's are no cheaper than class A/B.The power efficiency savings is minimal at best on a 4x100 amp.

I have yet to hear a full range Alpine PDX that I like as almost all of them seem to lack a midbass punch to them. I was told this can be corrected via equalization, but technically they shouldn't sound "funny".

The latest class D sub amps are more than competitive, they own the market right now.

Well, that depends. Finding a new Class D amplifier that gives me 600 watts RMS at 4 ohms versus used a Class AB amp resulted in me going with class AB due to cost alone. When you start needing 1,000 watts at 4 ohms, Class D amplifiers really start to get expensive

 

[mcsoul 10+ year member]

Well, that depends. Finding a new Class D amplifier that gives me 600 watts RMS at 4 ohms versus used a Class AB amp resulted in me going with class AB due to cost alone. When you start needing 1,000 watts at 4 ohms, Class D amplifiers really start to get expensive

Good point, generally your looking at a 175-250w 2 channel full range amp to get that power. There are just not a lot of choices out there in class D. Or a big as

hell class D mono amp that also puts down 3-4000w at 1 ohm.

 

[cleansoundzz 10+ year member]

I have yet to hear a full range Alpine PDX that I like as almost all of them seem to lack a midbass punch to them. I was told this can be corrected via equalization, but technically they shouldn't sound "funny".



Well, that depends. Finding a new Class D amplifier that gives me 600 watts RMS at 4 ohms versus used a Class AB amp resulted in me going with class AB due to cost alone. When you start needing 1,000 watts at 4 ohms, Class D amplifiers really start to get expensive

Yeah but running a class D @ 4 ohms is where you will get the best sound quality. After experiencing a high amount of bass over many years, then SQ is more important. SQ comes from not stressing a class D as much. I know RF has the T1500-1BD that will give out about 500 watts at 4 ohms. Class D if used properly can have the same SQ but again at higher impedances.//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif