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Audio Myths was "System I'm designing - two questions"
This came to my email. The post originated in RAC. I prefer to reply here as
well, there are others that can help to answer and debunk the audio myths better than I. ----- Original Message ----- From: "Les" Newsgroups: rec.audio.car Sent: Wednesday, May 19, 2004 6:30 PM Subject: System I'm designing - two questions "Aaron Russell" wrote in message ... a head unit without pre-outs? christ, that must be ancient.. first off, if you want clean, tight bass, go with an amplifier with a damping factor of 500 or better. BTW- Most supposed "audiophiles" usually say that 200 is enough. Go with any modern amplifier. The damping factor is a moot point nowadays and is merely a gimmick marketing tool to show a big number. "with higher frequencies, thats true, its not largely noticeable at comfortable hearing levels, but with lower frequncies, it is a drastically noticeable difference. amps with much higher damping factors have MUCH better control of the woofers. I thought the same as you, until I tested it for myself last year, comparing side by side, US amps DE-3000, and the USA-3000 , both setup with the same head unit(pre-outs had low-pass set to 100 Hz, all crossovers and subsonic filters disabled on the amps, wired to the same subwoofer configuration, 3000x1 watts @ 2 ohms, and the gains were adjusted on both amps until they outputed 130 dB at 40 Hz, for testing purposes. I tried to eliminate any varibles other than the amps themselves.. anyways, the results were as follows: the DE-3000 (advertised damping factor of 200) did NOT have NEARLY the amount of woofer control that the USA-3000 (advertised damping factor of 2200), there was an amazing difference in woofer "tightness" and control, not really noticeable so much when you'd play straight test frequencies through it, but once it was set, playing highly bass reactive music through it, like speed metal and various rap tunes. anyways." Let me see your data. Where are your measurments? It sounds like you relied solely on looking at the woofer and listening. Both "tests" which don't hold any water. It is the same snakeoil techniques that marketing people use to get people to believe the myths anyway. You attempted to make your tests valid, but without data and measurements it was all for not. "the engineers over at US AMPS told me on the phone it was because of the high damping factor, and i choose to believe them, since thats what they went to college for." You just called up US Amps and talked to the engineers? It seems highly unlikely. Especially since if they knew what they were doing they would have told you the truth about damping factor. I did some more research on damping factors and relation to SQ. Here are some of my results. I found conflicting websites, as I expected, and I noted one large difference between the 2 arguments. Those that are claiming the big SQ differences often had no data, other than the type of "evidence" you provided, the rare couple that did had virtually no explanation of how the numbers were acheived. Those that are saying that the big number DFs were really meaningless usually provided numbers, with explanations of how they are achieved, and most showed how it actually related to the speaker. Which how it actually relates to the speaker is important, and from what I have seen is overlooked by the Big number DF camp. Naturally I could find sites that are the other way, this is just generally what I found. (Yahoo search for "damping factor") Here is a few articles. http://www.trueaudio.com/post_013.htm http://66.218.71.225/search/cache?p=...yc=10240&icp=1 http://otlamp.com/articles/tomcik/ This is one of those, that is kinda right, but never provides any basis for the numbers achieved. http://www.leecao.com/caraudio/amplifier.html Now, a marketing blurb from my favorite pro sound amp company. (Notice no data, only touting thier amps) I found that most amp manufactures claimed that big number DFs are important, but most are like Crown and never provide any hard data. http://www.crownaudio.com/pdf/amps/136224.pdf Signal to noise ratio doesnt matter so much with bass frequencies, 95 dB or higher is fine.... if it doesnt advertise what the damping factor is, then chances are its ****ty Or they realize that every modern amp already has a high enough rating and there is no need to state it. .. i personally never really liek any of the JL amps for SQ, always thought they sounded too harsh, even when i had the Clarion DRX-9255 for a head unit. you want good SQ for a cheap price? im sure theres plenty of people that will argue with me on this, everybody has their opinions.. but The "low profile" Farenheit series from Power Acoustik, which is now discontinued, produced better SQ scores than my xtant, soundstream, or( i know im gonna get **** for this!) my ESX quantum amplifier setup. actually.. the ESX quantum amps( Q 175-2 and Q120-4 )had a slightly softer tonal quality, BUT, it distorted more at higher volumes.. Where to start?? Aaron, let me ask you a question and perhaps it will help dispell the myth. How can the amps sound different? "ohhh i dont know, different quality of crafstsmanship? different quality of components? different designs? they just sound different bro." They just sound different?? I don't think so. "Ever compare a tube amp to a solid state amp side by side? HUGELY different sound. They will look almost identical on an oscilloscope if adjusted right, but they will still each have a distinct sound." Sorry, I really meant SS amps. I forget to mention that, but since 99% of car amps are SS I thought it was an assumed. There is also more than an Oscope. And Tube amps and SS amps usually do not have thier specs within the threshold of human hearing. When you measure then, scope them, whatever and all the results come out with differences below the threshold of hearing then how can they possibly sound different? "i dont know, you tell me, since you seem to have all the answers," They don't. That is the answer. If you cannot measure a difference then how can you hear it?? Some mythical fairy just makes amps sound different? " go by what my ears tell me.. Sure, if you had a 50 band EQ attached to every amp setup to get them to sound EXACTLY the same at a given volume level, then yes, id agree with you.." That's the point. You don't need a 50 band EQ. Level match them, operate them within their linear limits, then measure them. The differences, if any, would be below the threshold of human hearing. The human ear is a remarkable ineffiencient and inaccurate device. The point of the amps sound the same argument for me is this, there are more important things to base a purchase of an amp on. When you operate an amp within it's linear limits, ie no clipping, then you will not be able to hear a difference, especially in a car. "this is absolute nonesense..there's always differences that are audible in every audio setup..otherwise ALL quality amps would cost the same because there was no real difference between them, and there woudl be no need for audio competition." Sure there a differnces in every audio setup. I never said there were not. Amps don't cost the same because of several factors, not just the supposed SQ. You are forgetting to price in quality, output power, features, and even reputation. There are SEVERAL factors into determining the cost of an amp. Your argument is becoming absurd. Your ESX distorted more at higher volumes because you were either clipping it or it was defective. "nope, they were fine.. i had 4 of the same amp.. all soudned the same." Then you were clipping it, or possibly hearing something that wasn't there. A softer sound is often associated with a lower volume. The physics of the matter support the fact that they sound the same, the I heard it argument is so full of holes it doesn't hold water. "ummm, what else would you have to go by except what you hear?" Of course, the ultimate goal of a car audio system is to sound good to you. But when you realize that there are not SQ differences in your amps it allows you to focus your search on important features to make sure you get the best amp for your situation. Then you can spend the money you saved by not purchasing that "SQ" amp and buy those speakers that you really liked. "and the physics DO support that amps will sound different. These amps dont all share the exact same componenets, do they? HIGHLY doubtful." They don't have to use the same components. Components can go into the quality of the amp, but not really the SQ. Your logic is flawed. Physics tells us that if we cannot measure the differences then HOW can we hear a difference? There are not differences to hear. If there is nothing to hear, then there is nothing to hear. Does that not make sense? Once someone from the "amps sound different" camp can come up with something besides "I heard it" or "They just does" then I might listen, for about a minute. Les |
#2
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Audio Myths was "System I'm designing - two questions"
They don't have to use the same components. Components can go into the
quality of the amp, but not really the SQ. Your logic is flawed. Physics tells us that if we cannot measure the differences then HOW can we hear a difference? The laws of physics tell us that, in order for a difference to be perceived by humans but NOT by the appropriate test equipment, one of two things must be true: 1) The test equipment is not precise enough to compete with human sensation. 2) There is another component that cannot be measured that is at play here. This would imply that another force is at work that has yet to be discovered (ie. not gravitational, electromagnetic, weak, or strong forces). (1) cannot be the case, because most test equipment generally used far exceeds the thresholds obtained in human psychophysical experiments. The amount of literature available in psychophysics in massive. It is a very active field. It must then be (2). So proponents of the notion that differences can be heard but not measured are essentially claiming that the reason they cannot measure differences is because the laws of physics are incomplete and that this has profound implications in the realm of audio. Call me skeptical. |
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Audio Myths was "System I'm designing - two questions"
MZ wrote:
It must then be (2). So proponents of the notion that differences can be heard but not measured are essentially claiming that the reason they cannot measure differences is because the laws of physics are incomplete and that this has profound implications in the realm of audio. But even what folks THINK they hear and cannot be measured can be verified by blind comparisons.... Let them use their ears ONLY without actually knowing what they are lstening to.. If they really can tell a difference they will be able to do so blindfolded using only thier ears... Most of the time folks that think they can, CANNOT when really tested this way... We condicted a cable test comparing 40ft of old nasty RCA cables VS very very ($2000) RCA cables of a very short length (I choose very opposite cables, VERY EXPANSIVE vs VERY CHEAP and VERY LONG vs VERY SHORT and still not one of the salesmen in a very high end store could tell the difference with their trained ears... Eddie |
#4
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Audio Myths was "System I'm designing - two questions"
...still not one of the salesmen in a very high end store could tell the
difference with their trained ears. People insert mental bias when choosing electronics. I sit and chuckle every time I read a review, either of home or car audio equipment, that claims one amp is "warmer" than another or "cleaner" or "more impactful" than another. 6 months ago I might've believed this crap but I've done a lot of asking questions and personal research (much of it on this NG) and I've found it be B.S. I compared my $1,200 Denon reciever to other Denon units as well as pieces manufactured by Pioneer, McIntosh, Sony, Theta and several others. I found that I couldn't indentify a single audible difference that could be attributed to the amps - even when comparing my unit to units costing $4,500 and more. |
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