Amps and Recievers- Tonal qualities???

[tbewick]

Which one is this?
In one of his tests 1986, he ignored 25% of the trials. That would certainly alter the results.

I think you will also like this reading:

http://home.att.net/~Wirebnder/articles/article_14.htm

A bit long but most interesting history of the early days, yet, not much has changed

Yeah, I'll have a look a that.

I don't want to criticise Martin Colloms' article but it is normal for results to sometimes be disgarded. Maybe the 25% didn't fill out their forms correctly. I haven't read the article, so it's difficult to comment on.

Thanks PENG for the explanation of torque and impedance.

 

[mtrycrafts]

Yeah, I'll have a look a that.
I don't want to criticise Martin Colloms' article but it is normal for results to sometimes be disgarded. Maybe the 25% didn't fill out their forms correctly. I haven't read the article, so it's difficult to comment on.
.

I happen to have a review of that comparison, in the Proceedings of the AES 8th International Conference, 1990, of a Mission and Pioneer power amp at an AES convention. 150 trials with 63% correct responses. "He ignored 25% of his sample because subjects refused to answer during some trials." Is that because they didn't hear anything different? In the end, it was poorly controlled.

 

[tbewick]

Which one is this?
In one of his tests 1986, he ignored 25% of the trials. That would certainly alter the results.

I think you will also like this reading:

http://home.att.net/~Wirebnder/articles/article_14.htm

A bit long but most interesting history of the early days, yet, not much has changed

Interesting article that.

"The first time that produced a result was in a test between our Hafler standard and a Mark Levinson ML series power amp. Almost everyone who listened to this comparison said the Levinson amp sounded "more present," "brighter," or "quicker." The last comment made me suspect something was wrong with the test, so I kept the Levinson amp long enough to put it on the bench. I found that the Levinson amp had a 2-3dB boost at about 3.5kHz, extending out to the top end roll-off of the amp."

I suppose that Nick250 was right, then. This of course is fairly common with speakers. I remember a Stereophile review commenting on how B&W often sweeten up their top-end making them more sound more detailed.

"I found that listening test volumes that averaged around 80-85SPL allowed for at least ten samples and the most predictable critical results... Many of our pro audio test subjects were uncomfortable listening to music at this low level and were unable to hear extreme frequencies at low levels. When this was true, they were also unable to tell the CS800 from the DH500 at a level where they felt more comfortable. As a baseline, once my younger test subjects became familiar with the test procedure and gained some experience in critical listening, they were incredibly consistent at identifying these two amplifiers."

This is surprising, as you'd expect that a typical power amplifier should perform very well/transparently at lower volumes. The B&W website FAQ attributes some tonal differences to crossover distortion. Doug Self's site also comments on distortion at lower output levels -

"...if you take a Class-B amplifier and increase its quiescent current so that it runs in Class-A at low levels, ie in Class AB, most people will tell you that the distortion will be reduced as you have moved nearer to the full Class-A condition. This is untrue. A correctly configured amplifier gives more distortion in Class-AB, not less, because of the abrupt gain changes inherent in switching from A to B every cycle."

- http://www.dself.dsl.pipex.com/ampins/pseudo/subjectv.htm#10

(He's talking about objective distortion measurements here, not audibility tests)

 

[Ern Dog]

I've also noticed that different manufacturers have different tonal output in terms of sounding warm, nuetral and bright. So if you feel your speakers sound a bit too bright, it helps to pair with a warm avr/amp as this helps smooth things out. I know that HK=warm, Denon=nuetral and Onkyo=bright.

 

[mtrycrafts]

I've also noticed that different manufacturers have different tonal output in terms of sounding warm, nuetral and bright. So if you feel your speakers sound a bit too bright, it helps to pair with a warm avr/amp as this helps smooth things out. I know that HK=warm, Denon=nuetral and Onkyo=bright.

If this were the case, the frequency response specs would show those characteristics. And, they would have to be of such magnitude to be audible and that is a pretty obvious variation of FR.
So far, I have not seen any well designed amps to exhibit such frequency anomaly.
These assigned characteristics are from perceptions or dubious reliability.

 

[Ern Dog]

If this were the case, the frequency response specs would show those characteristics. And, they would have to be of such magnitude to be audible and that is a pretty obvious variation of FR.
So far, I have not seen any well designed amps to exhibit such frequency anomaly.
These assigned characteristics are from perceptions or dubious reliability.

I agree that it is my perception. I've owned an Onkyo and currently have an HK and there is a huge tonal difference between the two.

 

[JAD2]

Now with all these replies and a weekend of playing at CC and BB, I'm at a point the conclusion is the following, which I had all ready said and everyones pretty much backed it in one form or the other.

Its all about power and being able to maintain the power throughout the frequency range and volume control in combination.

Bright systems will be ones that cannot hold their power up at low frequencies and drop off as volume is applied.
Neutral will be ones that dont drop off as far.
Warm ones will be ones that dont have a problem and go straight to their clipping point maintaining a proportional ratio of power to volume control.

When I went out to play I was using any receiver in the 65-130 WPC rating. It didnt matter how much power one was rated at, if they had trouble maintaining this power to volume ratio, they went bright. I drove those guys nuts lugging around the same 2 speakers and trying them on multitudes of receivers.

Ern Dog also has found the same thing I was seeing and has the same receivers I was going from and possibly too. My Onkyo sounded very warm against, Panny's, Pioneers, and everything else, but the Harman Kardon, then it sounded bright.
Then looking at the bench marks of power holding from a link I found, Harmon Kardon's always seem to be outputting more power than there rated too. Onkyo,s better than others, but less than the H'K's, with Denon right in the middle which goes with another poster and his comments about the 3.

I guess thats the conclusion!!

 

[mtrycrafts]

Now with all these replies and a weekend of playing at CC and BB, I'm at a point the conclusion is the following, which I had all ready said and everyones pretty much backed it in one form or the other.

Its all about power and being able to maintain the power throughout the frequency range and volume control in combination.

Bright systems will be ones that cannot hold their power up at low frequencies and drop off as volume is applied.
Neutral will be ones that dont drop off as far.
Warm ones will be ones that dont have a problem and go straight to their clipping point maintaining a proportional ratio of power to volume control.

When I went out to play I was using any receiver in the 65-130 WPC rating. It didnt matter how much power one was rated at, if they had trouble maintaining this power to volume ratio, they went bright. I drove those guys nuts lugging around the same 2 speakers and trying them on multitudes of receivers.

Ern Dog also has found the same thing I was seeing and has the same receivers I was going from and possibly too. My Onkyo sounded very warm against, Panny's, Pioneers, and everything else, but the Harman Kardon, then it sounded bright.
Then looking at the bench marks of power holding from a link I found, Harmon Kardon's always seem to be outputting more power than there rated too. Onkyo,s better than others, but less than the H'K's, with Denon right in the middle which goes with another poster and his comments about the 3.

I guess thats the conclusion!!

The power output at rated max level is not what you drive your music at continuously. You could not stand a continuous power of 60 watts across the band. What you may hear are some peaks here and there, hence you do not have full power across the full bandwidth. Not going to happen with music, only test signals.

Secondly, your comparisons along with ErnDog is somewhat unreliable, biased and flawed. So, I don't know why you accept the results as being meaningful.

 

[mulester7]

Secondly, your comparisons along with ErnDog is somewhat unreliable, biased and flawed. So, I don't know why you accept the results as being meaningful.

.....there's no doubt JAD and ErnDog will mend their thinking when they read your response....and, there's no doubt everyone here agrees with you that all receivers sound the same.....

http://pg.photos.yahoo.com/ph/mulester77/detail?.dir=47f8&.dnm=7bd5.jpg&.src=ph

 

[tbewick]

If this were the case, the frequency response specs would show those characteristics. And, they would have to be of such magnitude to be audible and that is a pretty obvious variation of FR.
So far, I have not seen any well designed amps to exhibit such frequency anomaly.

Isn't there the problem that the frequency response tests are usually done with an 8 ohm resistor, which only approximates a real loudspeaker load? From the B&W website FAQ:

"The amplifier should be capable of driving the complex impedance load of a speaker. This can require the amplifier to deliver higher current than it would when driving a simple resistor. A rough idea of the amplifier’s ability to drive a complex load can be gleaned from looking at the power output into different impedance loads. Usually, the power output is quoted into both an 8 ohm and a 4 ohm load. If there were no limit on the current capability of the amplifier, it would be capable of delivering twice the power into the lower impedance. Some amplifiers are capable of this; most are not, but the nearer to this figure you can get the better. Some of the best amplifiers can double the power again into a 2 ohm load and so on. Improved current capability translates into better control and dynamics, particularly in terms of bass attack."

- http://www.bwspeakers.com/index.cfm/fuseaction/local.faq/ObjectID/F5CA2628-3D20-11D4-A67F00D0B7473B37

The power output at rated max level is not what you drive your music at continuously. You could not stand a continuous power of 60 watts across the band. What you may hear are some peaks here and there, hence you do not have full power across the full bandwidth. Not going to happen with music, only test signals.

Isn't there still the problem that the continuous power output spec into 8 ohms does not realistically model a typical loudspeaker's impedance? I think Stanley Lipshitz contributed to a paper in the 80's which showed how a typical speaker's impedance can dip considerably (~2 ohms) on non-sinusoidal programme material.

 

[JAD2]

The power output at rated max level is not what you drive your music at continuously. You could not stand a continuous power of 60 watts across the band. What you may hear are some peaks here and there, hence you do not have full power across the full bandwidth. Not going to happen with music, only test signals.

Secondly, your comparisons along with ErnDog is somewhat unreliable, biased and flawed. So, I don't know why you accept the results as being meaningful.

Boy did you make a wild assumption from my post, a wild one.
Where did I say continuously and at full power?????
I said the power curve relationship with the volume control didn't stay in a proportional ratio with each other.
So as you turn up volume, some receivers appeared to have problem driving the low frequencies and not the higher ones that do take less power and are known too. So its like the mid/woofer drivers lost DB's, while the tweeters held up. This would make a system sound brighter.
Other receivers didnt have this problem as bad or at all, all the way up in volume til they began to clip/distort. Those sounded warmer.
So based on what I tried with what was available, no meters etc, just my ears, its not being unreliable, biased nor flawed. It was controlled by my fingers doing the turning up and my ears trying to hear when bass dropped in volume against the tweeters.
This is what appears to me the reasons some say receivers sound different. I didnt use a different set of speakers, I used the same ones so the load placed onto each receiver should have been the same. Then also tonal qualities couldn't be blamed on speaker choice.
Then comparing what I found between receivers that more than the majority admit at one time or another about each's quality, reputation and comparing it to the bench marks link I found. Systems that cant sub-stain their power ratings, some as much as 50% or more lower than rated, were bright. Those that could sub-stain their ratings were warm.

I'm asking, just like I began with, is this one of the reasons they sound different from one another. No special meters picking up thing we all cant hear, but some think they can, just using receivers, same speakers and ears!!

 

[Nick250]

I am not taking sides on this other than to say that unless all the receivers were driving the same speakers in the same room and all the internal processing (IE "pure direct") in each had been turned off or disabled it seems to me it is hard to draw meaningful conclusions about the SQ of the receivers. One might consider taking a few home and going from there.

Nick

 

[Buckeyefan 1]

JAD,

You bring up a good point. Many DBT's are done at a set volume, everything level matched. Your test was constantly changing the volume. So unless DBT's are done at a multitude of volume settings (that would be almost impossible for testers to remember everything), you could be right. Since not everyone listens to music at the same dB level, some units theoretically may sound different than others if what you are saying is true. Very interesting. This could open up a whole new can of worms at JAES.

 

[JAD2]

JAD,

You bring up a good point. Many DBT's are done at a set volume, everything level matched. Your test was constantly changing the volume. So unless DBT's are done at a multitude of volume settings (that would be almost impossible for testers to remember everything), you could be right. Since not everyone listens to music at the same dB level, some units theoretically may sound different than others if what you are saying is true. Very interesting. This could open up a whole new can of worms at JAES.

I'm glad someone has finally figured out what I was saying.
Back when I lived at home I always had the best speakers Dad would hand down, but never any decent power to put at them. He was addicted to this stuff and constantly kept changing to keep pace with changes in the market and going larger.But his amping, I could NOT have since he was a electronic hobbyist and built most all his own stuff or modified Dynaco kits. The speakers I got never sounded like they did on his amps because I could only buy used what my paper route allowed.
Now today after that old receiver I had died out and the speakers I last had rotted the surrounds out, kids drool etc, I got back into it again. Wife factor played heavily for sometime and does now, but not so much. Christmas 2 years ago the family pitched in and got me a Sony All in One system since I was really bugging the wife, missed my music. OK, better than nothing I guess and the wife actually liked it, and she's not Mikey OK. Honey!!!! Can I please have something that sounds good and not this crap?????
So off I was and finally after bringing home and trying out, ebaying and reselling the stuff, I found a set of speakers I'm sticking too. Was at a lose for funds, but after all the research I could muster picked a receiver off ebay for a steal. Nothing fancy as far as gimmicks, dont need nor want them, just Dolby Digital, DTS and different formats, no video crap, but it draws 4.2 amps, all ready had figured out why the Sony sucked besides the speakers.
OK, so now we have the TV, we got the speakers we want, DVD player and up converter and HD cable box. But I got this ???????able receiver. Bug has bitten, but looking at posts and all the opinions with it there must, be a common connector to this.
I read this
http://www.mastersonaudio.com/audio/20020901.htm
See this
http://tom-morrow-land.com/tests/ampchall/rcrules.htm
Then remember the old days and Dad old speakers and my affordable receiver.
There all controlled at X volume, Dad's amps kicked ***, my receiver ws underpowered to push them, HUM!!!
If what I think is the reasons, then I dont need a receiver, this goes plenty loud enough to piss the wife off, but a tad bit shy of what I would like to see, but rarely have the house empty to obtain.
Or do I bite the bullet and just do it, but without some supporting data and these numbers game companies claim , do I have another speaker deal coming where I just cant find it!!

 

[mtrycrafts]

JAD,

You bring up a good point. Many DBT's are done at a set volume, everything level matched. Your test was constantly changing the volume. So unless DBT's are done at a multitude of volume settings (that would be almost impossible for testers to remember everything), you could be right. Since not everyone listens to music at the same dB level, some units theoretically may sound different than others if what you are saying is true. Very interesting. This could open up a whole new can of worms at JAES.

Well, it may seem so at first read, but not really.

If you want to compare amps at different volumes, nothing stops you. You level match at 70dB and compare to statistical significance.
Then, you level match another round at 85 dB and repeat. Then at 95.

However,

http://home.att.net/~Wirebnder/articles/article_14.htm

Our hearing mechanism is, at best, a secondary survival tool and is more poorly protected and optimized than our sight mechanism.

This was illustrated in two ways during ABX testing. If the test was administered at a relatively high volume (anything over 90-100SPL at the listening position) the testee would become unable to discriminate between significantly different signal sources almost immediately. At moderately loud, live sound volumes (95-110SPL) we were unable to administer tests with more than five test samples with a total test time of less than a couple of minutes before the test subject became unable to pick out even gross differences. I think this explains why live sound systems are typically so coarse and unmusical. Exposure to the ear-damaging levels typical of modern live sound not only does permanent and temporary damage, but reduces the critical capabilities of the audience within a minute or two. I found that listening test volumes that averaged around 80-85SPL allowed for at least ten samples and the most predictable critical results.


So, your hearing detection capability is also not linear and gets worse at high levels?

Besides, his whole protocol was flawed and unreliable at best.

 

[mtrycrafts]

I'm asking, just like I began with, is this one of the reasons they sound different from one another. No special meters picking up thing we all cant hear, but some think they can, just using receivers, same speakers and ears!!

No. You have not established a difference yet, just an unreliable perception. So, one cannot comment on audible differences based on unreliable perceptions.

 

[tbewick]

Boy did you make a wild assumption from my post, a wild one.
Where did I say continuously and at full power?????
I said the power curve relationship with the volume control didn't stay in a proportional ratio with each other.
So as you turn up volume, some receivers appeared to have problem driving the low frequencies and not the higher ones that do take less power and are known too. So its like the mid/woofer drivers lost DB's, while the tweeters held up. This would make a system sound brighter.
Other receivers didnt have this problem as bad or at all, all the way up in volume til they began to clip/distort. Those sounded warmer.
So based on what I tried with what was available, no meters etc, just my ears, its not being unreliable, biased nor flawed. It was controlled by my fingers doing the turning up and my ears trying to hear when bass dropped in volume against the tweeters.

I suggest you read this article by Stanley Lipshitz which will make it clear how conventional, non-blind testing is flawed. In the article, a digital audio adapter was ABX tested. It turned out that the test was set up incorrectly, with A and B being the same source.

"Because the "A" and "B" positions were completely identical due to this error, an unbiased decision for "X" should have produced a 50:50 split of "A" and "B" votes. Interestingly, it turned out that this was not the case, Tiefenbrun's votes being 14 for "A" and 9 for "B". Could something have been influencing his voting, or did he just prefer the letter "A"? A comparison of the actual "X" choices showed that during this series Tiefenbrun voted incorrectly in 16 out of 23 trials, although the sound from the loudspeakers never changed. [This proportion of incorrect guesses would occur in a truly random situation less than 5% of the time. - Ed.] What does this mean? We cannot say for certain, but the most logical explanation is that he was (perhaps subconsciously) voting on the basis of the relays' acoustic click difference which we had now revealed. If so, his remembrance of the sound of the A and B clicks was inverted. Be this as it may, the error we had made by leaving the tape monitor switch in the "source' position turned out to provide an interesting sidelight on the question of personal bias. It also illustrates one of the potential pitfalls of high-resolution blind testing, and the danger of jumping to conclusions before very carefully checking the test setup."

- http://www.bostonaudiosociety.org/bas_speaker/abx_testing2.htm

This highlights the unreliability of non-controlled tests. People expect and think that they can hear a difference between two products, and therefore they report a difference.

Doug Self's site mentions subtraction testing as another good test of amplifier performance -

"...An alternative (and more popular) explanation is that standard sinewave THD measurements miss the point by failing to excite subtle distortion mechanisms that are triggered only by music, the spoken word, or whatever. This assumes that these music-only distortions are also left undisturbed by multi-tone intermodulation tests, and even the complex pseudorandom signals used in the Belcher distortion test. [16] The Belcher method effectively tests the audio path at all frequencies at once, and it is hard to conceive of a real defect that could escape it.

The most positive proof that Subjectivism is fallacious is given by subtraction testing. This is the devastatingly simple technique of subtracting before-and-after amplifier signals and demonstrating that nothing audibly detectable remains. It transpires that these alleged music-only mechanisms are not even revealed by music, or indeed anything else, and it is clear that the subtraction test has finally shown as non-existent these elusive degradation mechanisms."

- http://www.dself.dsl.pipex.com/ampins/pseudo/subjectv.htm

He has a picture of a loudspeaker in the set up diagram for this test, which will, of course, present an absolutely realistic impedance load for the amplifier.

I should say that just re-reading the whole thing, he does mention crossover distortion earlier in the text (which I brought up in my previous post):

"An objection often made to THD testing is that its resolution does not allow verification that no non-linearities exist at very low level; presumably some sort of micro-crossover distortion. Hawksford, for example, has stated "Low-level threshold phenomena... set bounds upon the ultimate transparency of an audio system" [7] and several writers have claimed that some metallic contacts consist of a net of so-called 'micro-diodes'. Actually, this sort of mischievous hypothesis can be easily disposed of using enhanced THD techniques. I evolved a method of measuring THD down to 0.01% at 200 microvolts rms, and applied it to large electrolytics, connectors of varying provenance, and lengths of copper cable with and without alleged magic properties. The method required the design of an ultra-low noise (EIN= - 150 dBu for a 10 source resistance) and very low THD."

- above link

 

[JAD2]

OK, I read those links you guys posted and the ones I found and others along with re-reading all the replays.
The conclusion then I could make would be, NOBODY KNOWS, EVERY test is invalid, un-reliable, skewed, our ears suck and so on. In every one of those articles, no one can agree on a method thats suitable and that someone else will go to any means to disprove that one persons ideal. I mean its all there in between the lines, so to speak.
Then you got professionals, audiophiles and so on that are deaf. This leaves you being more confused then you all ready were and picking from these series of so called professionals, you pick the ones you deem to be true.

But against all that, I saw a pattern in which my personal test is definitely different. There using real amps, I would call them, definitely not something you find at CC, BB and other places of those sorts, generically available to which I did. Most would agree that alot of these names are so generic they dont even get a Audiophile recognition and would sound different. Then I say due to power falling off in ratio to volume could be a reason that WE hear differences or I did. But then again you could by everything I read find faults with any testing just to prove something else.

Round and round and round with no end in sight!!!

 

[mulester7]

.....agreed, JAD, you're posting good stuff....and what about that idiot with four inch thick glasses Mortimer Stagmire Lipshitz who couldn't even set the "comparison" up right?....I don't believe I'da posted that one....Guys, if you want to let posts that quote lemmings who are desperate for published recognition say you didn't hear what you thought you did, and it rule you, go right ahead....what this site needs is advice for persons new to the hobby, or members considering purchases....in your best words, describe what you hear from your equipment, period....then when someone comes at you saying your report is not creditable, tell them to get a life, fly a kite, go actually compare some equipment, and quit reading so much....aaahh, reviews, aren't all of them wonderful?....hey, totally positive flag-waving reviews are what made me buy the WORST pre-amp I have ever heard....took a whole 10 seconds of listening....simply tell us what you hear, Gentlemen, and USE THE IGNORE FEATURE IF YOU NEED TO DO THAT, TO BE ABLE TO ENJOY COMING TO THIS SITE AND POSTING....put yourself in the position of the asker if you have the piece of equipment they ask about, and recognize they want to spend their hard-earned money in the best direction....Mortimer Stagmire Lipshitz needs our vote for Dog-Catcher......

 

[Ern Dog]

.....agreed, JAD, you're posting good stuff....and what about that idiot with four inch thick glasses Mortimer Stagmire Lipshitz who couldn't even set the "comparison" up right?....I don't believe I'da posted that one....Guys, if you want to let posts that quote lemmings who are desperate for published recognition say you didn't hear what you thought you did, and it rule you, go right ahead....what this site needs is advice for persons new to the hobby, or members considering purchases....in your best words, describe what you hear from your equipment, period....then when someone comes at you saying your report is not creditable, tell them to get a life, fly a kite, go actually compare some equipment, and quit reading so much....aaahh, reviews, aren't all of them wonderful?....hey, totally positive flag-waving reviews are what made me buy the WORST pre-amp I have ever heard....took a whole 10 seconds of listening....simply tell us what you hear, Gentlemen, and USE THE IGNORE FEATURE IF YOU NEED TO DO THAT, TO BE ABLE TO ENJOY COMING TO THIS SITE AND POSTING....put yourself in the position of the asker if you have the piece of equipment they ask about, and recognize they want to spend their hard-earned money in the best direction....Mortimer Stagmire Lipshitz needs our vote for Dog-Catcher......

I couldn't agree with you more.
At the end of the day, when I turn on my stereo, the only thing that matters to me is my PERCEPTION of how my rig sounds. My ears (as flawed and unreliable as they are) are the biggest factor in shaping my perception. So when I'm buying gear- specs, reviews, research, etc are all important factors, but for me they come behind "How does this sound to ME." Even if everybody else thinks that it sounds like crap, if it sounds good to you than that's all that matters.