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In Reply to: RE: Do you realize posted by morricab on January 01, 2008 at 09:51:47
>>Well AH, IMO that is the red herring a lot of people keep dragging around
really....
>>This means that it all gets back down to at what level are various distortions audible??
Your opinion ofcourse, but is it valid?
>>I am of the mind that it depends very much on the type of distortion more than the amount, although excessively high distortion of any kind is probably best to avoid
I will side with Earl Geddes on this one as the measurements back his viewpoint, i.e. they are small effects.
Music making the painting, recording it the photograph
Follow Ups:
"Your opinion ofcourse, but is it valid?"
Why would it not be valid? Distortion is only a problem if it is audible is it not? Do you watch the music on an oscilloscope or do you listen to it with your ears?
"they are small effects."
Is that so? Did you side with Geddes then with your wallet? I didn't think so. You know he once told me that he got great sound from his $150 Pioneer receiver and he didn't feel the need to spend more. I believe that for him it was true but would it be for you? For me, I can easily hear the difference in quality and therefore I put my money into the best amplification that I can afford. So to me the effects are not small but make the difference between lifelike sound and tincan sound. So you can claim to side with Geddes but I know that you have a Sharp Class D amp that was over $20,000 when new so you don't really believe that the differences in amps is small and inaudible now do you?
> Why would it not be valid?
Why would it be valid?
> Distortion is only a problem if it is audible is it not?
Well..
> Do you watch the music on an oscilloscope or do you listen to it with your ears?
I use both to evaluate hardware quality.
> For me, I can easily hear the difference in quality and therefore I put my money into the best amplification that I can afford. So to me the effects are not small but make the difference between lifelike sound and tincan sound.
this just happens to be a site for technical discussions, so I do not think it is unreasonable to ask for evidence that goes beyond just 'I know what I hear'
> So you can claim to side with Geddes but I know that you have a Sharp Class D amp that was over $20,000 when new so you don't really believe that the differences in amps is small and inaudible now do you?
It's the facts that count not what I believe. I am simply asking you to back your opinion with something more than just your belief.
PS: small effect does not necessarily mean inaudible, at least not in the context used.
Music making the painting, recording it the photograph
"Why would it be valid?"
Its rather obvious isn't it? I mean the level at which different distortions are audible is rather the whole point in determining the ultimate quality of the product. Just making arbitrary specifications because "lower is better" regardless of the methods used to "lower" distortion is not really a very valid way of doing things, although it seems to be the standard way of doing them. It turns out that the most common method for "lowering" distortion has problems of its own just like digital, while having lower distortion in the conventional sense, introduced other kinds of distortion. There is no free lunch!
"Well.."
Well what? If there is some other reason distortion is important beyond being possibly audible then please tell me what that importance would be.
"It's the facts that count not what I believe. I am simply asking you to back your opinion with something more than just your belief."
Don't try to turn it around, you have made a conscious choice to buy a very expensive piece of electronics that was based on listening I assume. If you claim it was also based on measurements then I can point out many other amps with as good or better measurements that cost far less money. You coming on here and agreeing with Geddes that amplifier distortions are small effects yet you have spent a large sum of money on an amp?? Why didn't you simply spend that money on some Geddes speakers and use a $150 Pioneer receiver?? A bit hypocritical don't you think?
What "facts" do you actually have? You have data but not facts. What kind of correlation do you have between measurements and listening preferences? If you have tools that allow me to do this then by all means present them. Numbers don't mean much if they don't correlate with real experience in this case. Afterall, we are talking about the listener as the final arbiter of sound quality are we not??
Now, Geddes developed actually a pretty decent metric for correlating distortion with perceieved sound quality; however, when I questioned him about it he said that it was mainly for loudspeakers because he didn't "believe" that "well designed" (whatever that is supposed to mean and by what criteria is an amp considered well designed??) amps sounded essentially the same or rather their affects were so minor as to not be important. I told him that I thought his metric might be useful in determining what made a good sounding amp. What he fails to understand is that the distortions of speakers and electronics do not really mask each other as they are fundamentally different in nature. So while "small" they can nevertheless be quite annoyingly audible.
I used the metric from Cheever's paper once to determine amp quality. The ones that came up best were not surprisingly ones with the least high order distortion. Now I have heard most of the ones that I applied this metric to and the results from listening were similar to the metric. I got the measurements from Stereophile and Soundstage. No, I haven't gathered all of these amps together in a room and tried them one after the other and then measured them. I had to take the data where I could find it and I listened to these amps under different conditions; however, I remember if they sounded good or not and those I remember sounding good had the better numbers using the Cheever metric. For example, I am not a huge fan of Wilson speakers but I found that they sounded really good once paired with a Lamm amp. I heard other speakers with Lamm amps and it never failed to sound at least very good. The same is true of OTL amplifiers I have heard and/or owned.
In fact, I think you have nothing beyond your belief in what you hear as well. You have used no metric to correlate measurements to your own hearing, have you? Didn't think so. Again, measurements in and of themselves are meaningless unless you can correlate them with audible effects or determine for sure that they are inaudible.
When I take data in the laboratory we have to correlate that data with real chemical and physical phenomena or at least to a model that describes the behavior of those phenomena, otherwise the data could describe anything or nothing. It has to RELATE to something unless perhaps it is being used merely as a QC tool. Many engineers have this "lower is better" mentality without thinking carefully how it relates to the listening. Lowering one kind of distortion often has the effect of introuding other distorions, which are perhaps more audible than the original and thus defeating the purpose of lowering the original distortion in the first place.
Digital introduced us to new distortions, even though it was much lower in "traditional" analog distortions. Many find them more objectionable than the older, higher in level, distortions. Now Class D amps are introducing completely new and different noise and distortion into amplification and the result is a sound that is unlike either tube or SS! Some don't mind the dryness of tone that I hear but those of us with natural instrument tone high on the priority list find them unlistenable for the long term (I have owned and sold two different kinds).
I have also used Keith Howard's little programs (look for his article on "euphonic distortion" in stereophile) to add distortion to a musical track. Howard did it in a very generic way and found that ALL audible distortion was worse than no added distortion; however, he also found that a progressively reducing distortion level with even and odd harmonics sounded the least objectionable.
I took it one step further, I looked up the distortion patterns published in Stereophile and Soundstage for 5 or 6 "top" amplifiers and added their distortion patterns to a short piece of music. The music I chose was a solo violin as I know the sound well. The distortion was audible on all the tracks where it was added and worse than the undistorted track. The best sounding one was the Lamm amp followed closely by another SET. The worst was a SS amp with high negative feedback. Guess which one had lower distortion??
" small effect does not necessarily mean inaudible, at least not in the context used"
I agree but he is clearly meaning it as audibly insignificant. To this I would say "Maybe to his ears" but if I have learned one thing from these phase distortion discussions the audibility and significance of certain distortions is HIGHLY listener dependent.
An interesting website looking at distortion audibility:
http://www.klippel-listeningtest.de/lt/default.html
Hold on, let's rewind... what do you disagree with?I said
"I am willing to wager that SOME of the measurements were similar but not all e.g they might the same FR into standard test load, but that's a whole 'nother matter. If they sounded different (i.e. not the observer's fanciful imagination), some of the parameters will measure differently "
Where did you get
Just making arbitrary specifications because "lower is better" regardless of the methods used to "lower" distortion is not really a very valid way of doing things, although it seems to be the standard way of doing them. It turns out that the most common method for "lowering" distortion has problems of its own just like digital, while having lower distortion in the conventional sense, introduced other kinds of distortion. There is no free lunch!
How did you infer all this, certainly not from my comments, your post disputes points I never made.
Don't try to turn it around, you have made a conscious choice to buy a very expensive piece of electronics that was based on listening I assume. If you claim it was also based on measurements then I can point out many other amps with as good or better measurements that cost far less money. You coming on here and agreeing with Geddes that amplifier distortions are small effects yet you have spent a large sum of money on an amp?? Why didn't you simply spend that money on some Geddes speakers and use a $150 Pioneer receiver?? A bit hypocritical don't you think?
You have built yourself a nice little conundrum. If I owned a cheapo amplifier you will claim I don't know what expensive amplfiers are capable of. Conversely since I own an expensive one you claim I am a hypocrite for commenting on the veracity of measurements in verifying audible differences. How cool is that!
To cut the long story short, You are arguing against a point I never made i.e. you have built a strawman. My point is simple, audible differences are (at very least potentially) measureable differences. Do you disagree, if yes, why?
Music making the painting, recording it the photograph
"I will side with Earl Geddes on this one as the measurements back his viewpoint, i.e. they are small effects."
"You have built yourself a nice little conundrum. If I owned a cheapo amplifier you will claim I don't know what expensive amplfiers are capable of. Conversely since I own an expensive one you claim I am a hypocrite for commenting on the veracity of measurements in verifying audible differences. How cool is that!"
You are the one claiming the effects are small and thus you have built the conundrum for yourself. If you had said, "I think the effects of distortion in amplifiers are important to good sound" or some such thing and then I see you have a very expensive amplifier you will get no issues from me. The fact that YOU made the statement agreeing with Geddes that the effects are small and YOU own the expensive amplifier means that YOU made the hypocritical statement not me.
"My point is simple, audible differences are (at very least potentially) measureable differences. Do you disagree, if yes, why?"
I will grant you that it is now your point and address the question with the answer of maybe. There are definitely audible traits present in the measurements but it is not at all straightforward to tease the information out of basic static measurements. There is still no consensus on correlating measurements with listening preferences!! This is why I made this point in the previous post. It is not a strawman because as it stands now there is no straightforward way to correlate listening and measurements. Cheever's model is not bad and neither is Geddes model but they are not straightforward to implement and no one who is designing amps or whatever is really using them (except perhaps Geddes himself on his speakers).
In principal though I believe it SHOULD be possible to tell which of two pieces of gear is LIKELY to sound better to the MAJORITY of listeners by some metric. Also, no two pieces of gear ever measure exactly the same so differences could at least tell us something about the sound differences but as far as I know, no one has a way to do this comparison.
So actually I argued against two point that you made, which you apparently don't realize that you made. 1) the effects are small (you agreeing with Geddes confirms this point) and 2) Audible differences translate into measureable differences. The first point is IMO just wrong and hypocritical of you to say so as I explained above and the second point I am only partially disagreeing with because in principal you are right but in practice this is wrong and no good correlation exists between measurements and listening.
"You are the one claiming the effects are small and thus you have built the conundrum for yourself. If you had said, "I think the effects of distortion in amplifiers are important to good sound" or some such thing and then I see you have a very expensive amplifier you will get no issues from me"This is a classic ad hominen, How does an anargumentum ad hominem buttress your point? I suggest that in future, you make your point on the basis of facts rather than arguing against the person.
Moving on, you say
"So actually I argued against two point that you made, which you apparently don't realize that you made. 1) the effects are small"
So you disagree with my comments but pray tell how does it invalidate the original point which was "If they sounded different (i.e. not the observer's fanciful imagination), some of the parameters will measure differently". Besides this comment
"I will side with Earl Geddes on this one as the measurements back his viewpoint, i.e. they are small effects"
was a response to another tangential comment, where you said
"This means that it all gets back down to at what level are various distortions audible?? I am of the mind that it depends very much on the type of distortion more than the amount, although excessively high distortion of any kind is probably best to avoid"
Which is a non sequitur as it clearly does not follow from the original comment which you now accept is correct in principle. Thanks anyway for taking me on a merry-go-round.
Music making the painting, recording it the photograph
Exactly why did you buy the amp you bought and why did you not choose a less expensive one of equal or greater capacity to drive your speakers?
Exactly why did you buy the amp you bought and why did you not choose one of much greater capacity to drive your low sensitivity speakers?
cheers,
AJ
This post will last approximately 2 minutes. 120,119,118,117...
At the time I bought that amp. 1985 it was by far the best sounding amp i heard with the Martin Logan CLS speakers. I lived quite happily with that combination along with a Vandersteen subwoofer for nearly twenty years. I only bought the Soun Labs a few years ago. The D 115 does a fine job of driving the Sound Labs but I agree I could use some more power. My next upgrade will be a more powerful amp but it will have to sound as good or hopefully better than my current amp for the first 100 watts which is almost everyyhing. But I don't bring drum kits into my listening room as a reference ( unlike you I know better than to do such a stupid thing) so I don't need ear damaging SPLs to make me happy.
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