The “Sound” of receivers…

[Rip Van Woofer]

Oh, and I don't think this thread needs to be locked. So far is has been quite civil, even on the part of the !@$# who disagree with me!

 

[Rob Babcock]

You know, one of the rude shocks when I got back into audio after so many years away was, "hey, where's Stereo Review?!?" Kind of like that scene in Romancing the Stone(?) where the hero who has been a jungle pilot finds out the Doobie Brothers broke up years ago.

To me the greatest tragedy was whenAudio magazine folded. That was my favorite. Stereo Review had been S&V for quite awhile before I noticed the old mag was "gone"- I had a spell, too, where I was out of audio as far as not reading the rags or buying new gear.

 

[mtrycrafts]

WOW. This thread really took off…]

Never a dull moment here



I do believe that many people will be able to tell the difference between receivers ONLY IF they use each receiver’s internal amps. Why? Because I’m of the opinion that when amps approach their limits, they distort in different ways. The unique distortion of a receiver's amp would give that receiver a distinctive sonic signature.

Oh, ok. When it is clipping, it distorts and that is audible with different sonics. Not a problem. But, is that what one is looking for? How it sounds when it is clipping? Hope not as we try to operate in the designed limits, that is the goal

(Please bear in mind…I do not think that amps have a sonic signature when they are not pushed beyond their “comfort zone.” I just believe that its very easy to push a typical 100W or even 200W amp to its limits with out even realizing it.)

Hard to argue or discuss audibility when it is driven to the limits. Maybe the answer is a bigger amp, an amp with good dynamic headroom, more sensitive speakers, or listening at lower levels

 

[b_panther_g]

…But, is that what one is looking for? How it sounds when it is clipping? Hope not as we try to operate in the designed limits, that is the goal.

I agree. I don’t want to judge gear on how well it clips. An accurate reproduction is the goal of Hi-Fi. And clipping from a receiver’s amps can’t be considered accurate by any stretch of the imagination. But, I think it’s easy to turn the volume knob just a little too far to the right. Everyone I know turns the volume up when they play a song they like.

Now, how powerful are receivers? Some top of the line receivers can handle about 200W. Here’s a quote from Axiom’s site. It’s called “Secrets of Amplifier and Speaker Power Requirements Revealed.”
(http://axiomaudio.com/archives/power.html)

“…So adding a second M80ti will raise the loudness at 12 feet from 83 dB to 86 dB. And don't forget we're still using 1 watt of amplifier power output into Axiom's most sensitive speaker. But how loud are real-life instruments, orchestras and rock bands? Now, while 86 dB SPL is "fairly loud," it's not nearly as loud as what you might hear from a good seat at an actual rock concert or from an orchestra or pianist in a concert hall. A solo grand piano can reach peak levels of 109 dB SPL, a full orchestra and chorus in a concert hall will measure 106 dB, and a rock group, 120 dB SPL. Now let's try and get our peak speaker sound levels to 96 dB, "twice as loud" as our 86-dB listening level. That isn't that difficult because right now we're only using 1 watt per channel to drive the M80ti's to 86 dB. So we'll need ten times as much power, or 10 watts, to reach 96 dB. Big deal. We've got lots more.

But things begin to change, and rather dramatically. Let's push the M80ti's to what we might experience from a solo grand piano, 109 dB. We're at 96 dB with 10 watts per channel. Let's go to 106 dB. So that requires 10 x 10, or 100 watts. Close, but not quite there yet. Just 3 dB more. Remember, we have to double the power for a 3-dB increase in sound level. So 100 watts becomes 200 watts. Yikes! Our receiver has only 110 watts maximum output! We've run out of amplifier power! And what about the rock concert? Let's lower our expectations and aim for 119 dB. Going from 109 dB SPL, which needs 200 watts per channel, to 119 dB SPL (get out your ear plugs) is another 10-dB jump and--you do the math--that requires 10 x 200, or 2,000 watts per channel!”​

That’s a lot of power – even if it’s only for a brief moment. Even though I don't listen at rock consort levels, I've got a lot of action DVDs and some music that have VERY loud peaks.

“Maybe the answer is a bigger amp, an amp with good dynamic headroom, more sensitive speakers, or listening at lower levels”

I agree with you. I’m looking for sensitive bookshelves and pro amps that deliver as much power as I can afford. I’m also looking for a receiver that’s as accurate or true to the music as possible. Which leads me to ask…

Do receivers have a sonic signature of their own?

I don’t know. Does anyone know?

Later,
B

 

[mtrycrafts]

[

I agree with you. I’m looking for sensitive bookshelves and pro amps that deliver as much power as I can afford. I’m also looking for a receiver that’s as accurate or true to the music as possible. Which leads me to ask…

Do receivers have a sonic signature of their own?

I don’t know. Does anyone know?

Later,
B

I would look at the specs first, right off the bat. Why even consider one that has frequency response problems, or no dynamic headroom to speak of, or distorts, or noisy. But, designing a transparent amp is not rocket science
So, in most cases I would say that they don't when doing a bais free comparison.

Interesting article. By the way, an Axiom line was reviewed in current issue The $ensisble $ound. A Canadian company that follows the research conducted at the NRC in Canada.

Also, one must consider a speakers property, its distortion and compression at high levels. Perhaps it is the speaker that is pooping out, not the receiver Certainly not many will deliver 120dB spl. One only has to look at subwoofer tests.

I have listened to some organ performances, took my spl meter, boy, it seems loud at 106dB spl, I cannot imagine 120

 

[Rÿche 1]

We won't know for sure untill this happens. Historically the odds are against you

Well, I KNOW. I knew it the first song I listened too.

 

[mtrycrafts]

To be totally fair, though, a negative result is only that- just a data point. A failure to distinguish in any given test only means the participants of that test can't hear a diff, not that there isn't one. I'd say to be statistically convincing you'd need a lot of subjects and/or a lot of tests.

I'm not saying they do sound the same or they don't. Despite a few studies and a lot of arguing, I've yet to see ironclad proof either way. How's that for hedging my bets?

You are right
Always a But
How many tests will be enough? Do we test the whole pupulation? Maybe we don't even have a representative numer yet but, what is interesting is the lack of positives

Yes, hedgiong bets is an easy way out. I jump right out on the limb. I should have participated in the gymnastics

 

[Rob Babcock]

Actually, we do have positives. I just haven't found the article yet to show it to you.

 

[mtrycrafts]

Actually, we do have positives. I just haven't found the article yet to show it to you.

Well, ok, you need help in searching the pile

 

[mtrycrafts]

Actually, we do have positives. I just haven't found the article yet to show it to you.

Here is a link to the person who has done a lot of the amp tests

http://www.mastersonaudio.com/audio/20020901.htm

 

[Rob Babcock]

Good link. I read that a year and a half ago, but it's just as valid now as then. I like the way he says the response got more agitated the closer it got to the sales floor!

 

[ruadmaa]

A Truly Excellent Article

Here is a link to the person who has done a lot of the amp tests

http://www.mastersonaudio.com/audio/20020901.htm

Thank you for that most informative link, it should be required reading by anyone interested in audio. It's truly amazing how many people fall for sales hype no matter if you are talking cables, amplifiers, or anything else to do with A/V. Fascinating how they describe how the sound stage opened up, highs were much cleaner and so on and so on when, in fact, there is no difference at all. Remember how putting green marking pen on your CD's was guaranteed to make them sound better???

I think the Masters article was exactly what the Audioholics people had in mind when they created this website. The "truth" about audio.

 

[Polkfan]

Nice article! Count me in the skeptic camp. The power of suggestion can have a huge influence on the uninformed.

 

[Rip Van Woofer]

I've mentioned these papers before: Go to the AES Website and and find the David Clark papers on ABX testing. Spend the five bucks for each paper (they're called "preprints"). Ten years' of tests should be a large enough sample, hmm?

And a word about positives: think back to your basic stats and probability class if you took one (I didn't but, willy-nilly, did get some of the fundamentals elsewhere). Any random phenomenon (like a coinflip, or sheer guesswork in any kind of a/b test) will sometimes generate seemingly non-random behavior (like a run of "heads") - a positive*. Similarly, even a well-conducted double-blind study that ends in a null result will sometimes generate an anomalous positive (or even a few) among a large number of nulls. This might give the appearance (in an audio test) of the presence of a person (or even a few persons in a large test) with "golden ears".

The presence of a small number of positives vs. a large number of nulls can be very intriguing and may suggest the need for further examination. If poor methodology (including experimenter bias, group pressure, etc.) is ruled out as a cause for the anomalous positives, one simple test is to run the test again with those reporting positive results and see if they repeat.

If a sufficent number of trials has been run, there might be a point where a small number of anomalous results can be confidently "written off" but I don't know the number (x percent?). I suspect our old friend the bell curve applies here somewhere.

I believe that sixteen to twenty trials per subject (person) is generally considered statistically sound, BTW.

*And that is how gambling works, too. The occasional "lucky" hit in a random sequence of events is enough to reinforce the behavior and keep the sucker coming back for more. There's a term for it but my Psych 101 class was long ago. Same mechanism can convince a person that there is "something there" in a string of random results (this amp sounds better than the others, the chicken sacrifices finally ended your bad luck in love) when there isn't. We humans survive and thrive in part by recognizing patterns. Trouble is, sometimes we see them where they ain't.

('Scuse me...gotta find a chicken and a sharp knife before I send out these resumes...)

(Polkfan: great sig re: 'philes vs. music lovers!)

[EDIT] The "Masters on Audio" article is superb, and I hadn't seen it before. I just added a link to it on my Webpage. Hard to imagine a more succinct presentation of the facts. It and other lengthier and more technically oriented articles such as the Clark papers I mentioned and Doug Self's "Science and Subjectivism in Audio" (link to it from my "Audio Wisdom" Webpage, see signature below) should be more than sufficient for any rational person.

 

[Rob Babcock]

Good point, Rip. But it's not like S&V did 3 flips and called it good- the test was pretty thorough. Wish I could find that friggin' issue! I wasn't there when the test was done, so I have no idea if something buggered their test. At any rate, I'm not saying you're wrong.

The papers you quote would be interesting, but I probably won't really have the ambition/drive to see out and buy them (besides my current broke-ness!)- I'll just take your word about what they say. If you still have the papers, can you briefly outline how they were conducted? What type of speaker was used? How were they level matched?

Is the ABX Comparator still made nowdays? I'd thought I'd heard it was no longer being manufactured? Just curious; if not I'm sure someone still makes a comparable product.

 

[mtrycrafts]

Fascinating how they describe how the sound stage opened up, highs were much cleaner and so on and so on

Well, humans are a creative bunch

Remember how putting green marking pen on your CD's was guaranteed to make them sound better???

How else would it sell withouth such a guarantee

I think the Masters article was exactly what the Audioholics people had in mind when they created this website. The "truth" about audio.

We should all be thankful that there are some to keep the candle lit in a world full of darkness, (something Sagan would say )

Truth hurst at times.

 

[mtrycrafts]

The power of suggestion can have a huge influence on the uninformed.

Marketeering is becoming a scinece, and works well

 

[mtrycrafts]

I've mentioned these papers before: Go to the AES Website and and find the David Clark papers on ABX testing. Spend the five bucks for each paper (they're called "preprints"). Ten years' of tests should be a large enough sample, hmm?

And a word about positives: think back to your basic stats and probability class if you took one (I didn't but, willy-nilly, did get some of the fundamentals elsewhere). Any random phenomenon (like a coinflip, or sheer guesswork in any kind of a/b test) will sometimes generate seemingly non-random behavior (like a run of "heads") - a positive*. Similarly, even a well-conducted double-blind study that ends in a null result will sometimes generate an anomalous positive (or even a few) among a large number of nulls. This might give the appearance (in an audio test) of the presence of a person (or even a few persons in a large test) with "golden ears".

The presence of a small number of positives vs. a large number of nulls can be very intriguing and may suggest the need for further examination. If poor methodology (including experimenter bias, group pressure, etc.) is ruled out as a cause for the anomalous positives, one simple test is to run the test again with those reporting positive results and see if they repeat.

If a sufficent number of trials has been run, there might be a point where a small number of anomalous results can be confidently "written off" but I don't know the number (x percent?). I suspect our old friend the bell curve applies here somewhere.

I believe that sixteen to twenty trials per subject (person) is generally considered statistically sound, BTW.

*And that is how gambling works, too. The occasional "lucky" hit in a random sequence of events is enough to reinforce the behavior and keep the sucker coming back for more. There's a term for it but my Psych 101 class was long ago. Same mechanism can convince a person that there is "something there" in a string of random results (this amp sounds better than the others, the chicken sacrifices finally ended your bad luck in love) when there isn't. We humans survive and thrive in part by recognizing patterns. Trouble is, sometimes we see them where they ain't.

('Scuse me...gotta find a chicken and a sharp knife before I send out these resumes...)

(Polkfan: great sig re: 'philes vs. music lovers!)

[EDIT] The "Masters on Audio" article is superb, and I hadn't seen it before. I just added a link to it on my Webpage. Hard to imagine a more succinct presentation of the facts. It and other lengthier and more technically oriented articles such as the Clark papers I mentioned and Doug Self's "Science and Subjectivism in Audio" (link to it from my "Audio Wisdom" Webpage, see signature below) should be more than sufficient for any rational person.

To make it easy on the ambitious ones here, some of these cotations:

"Ten Years of A/B/X Testing", Clark, David L., Presented at the 91st AES Convebntion, Oct 91, Print #3167.

"High-Resolution Subjective Testing Using a Double-Blind Comparator", Clark, David, Journal of the Audio Engineering Society, Vol30, no 5, May82, pg 330-338.

"The Great Ego Crunchers: Equalized, Double Blind Testing", Shanefield, Daniel, Hi-Fidelity, Mar 80, pg 57-61.
This is about very long term listeing, several months, under DBT

"Topological Analysis of Consumer Audio Electronics: Another Approach to Show that Modern Audio Electronics are Acoustically Transparent", Rich, David and Aczel, Peter, 99 AES Convention, 1995, Print #4053.

"The Great Debate: Is Anyone Winning?", Nousaine, Tom, Proceedings of the AES, 8th International Conference, 1990, page 117-120.

 

[mtrycrafts]

Is the ABX Comparator still made nowdays? I'd thought I'd heard it was no longer being manufactured? Just curious; if not I'm sure someone still makes a comparable product.

Not the original one. That went out of production a long time ago. There are other iterations out there someplace.

Check this out, may be of some help if not aware of it.

http://www.pcavtech.com/techtalk/

 

[Rip Van Woofer]

There's a DIY ABX comparator on the Elliot Sound site. Wiring on the random switcher looks like a beotch. Link

Been tempted to try it myself someday.

BTW, the Southeast Michigan Woofer & Tweeter Marching Society (great name!), with whom Clark did a lot of his ABX research, is still in existence right here in greater Deeetroit. I am thinking of joining, though ABXing seems to be old news to them these days. They do still have a sceptical orientation.

Alas, I don't have the Clark papers and am only familiar with them thru numerous citations in other articles. I'm broke, too. From where I sit this sure feels like a "jobless recovery".

I read some other articles by Ian Masters after being impressed by the '"amp sounds" one...looks like a straight shooter and good explainer of audio topics. Worth a bookmark!

Rob, S&V seems to have some sharp cookies on staff like David Ranada so I imagine the test was conducted well. But I bet "something else" accounts for the positive result: I'm betting on an audibly colored tube amp from your initial report.