FORUMS
Human perception is complex, this we know. Analysis of non-linear systems is also complex.
Let me offer just one example. If we pass a pure tone (sine-wave for example) through a non-linearity the spectrum in the frequency domain will reveal new distortion components. If we take another non-linearity that complements the first one, it will also add new components in the frequency domain, however if the cascade of these two non-linearities provides an overall linear transfer function then the output will have the intermediate distortion removed and will be undistorted. This is highly unintuitive. One example of this is in the design of function generators, where a triangular waveform is first produced, it obviously has strong harmonics, and then a decent sine-wave is produced by passing it through the non-linearity of a differential pair (at the correct amplitude). Another example is pre-distortion used in some pro analog tape recorders. This is not to suggest that any of this goes on in Hi-Fi component matching, just that the understanding of non-linear systems can be highly complex.
Back to when Bad is Good. I have always wondered why consumers often prefer products that by most standards are technically inferior. I do not believe the often offered excuse that we are measuring the wrong things, more likely the defects in some complex way are "better" or more interesting due to some complex factor, or even misuse of the equipment. I offer a few obvious cases here in the hope that it might spark some interesting conversation.
LP vs. CD - It is clear that LP adds more distortion, even at moderate levels. LP does provide softer overload and perhaps this is part of it. Most moving coil pickups provide a tilted up high end that will be heard as more air and detail. I posted this here (I am PB2):
http://www.diyaudio.com/forums/showthread.php?postid=1016793#post1016793
Digital when used correctly is highly linear, and nearly ideal. However, it does exhibit hard clipping in overload which should always be avoided, but - unfortunately often is not. I have several CDs that sound fine most of the time, but sounded as if there was clipping on the peaks. I confirmed that there was significant clipping by inspecting the digital waveform by plotting it in a digital editing software program. No doubt, the digital format is being misused. An interesting read:
http://www.bostonaudiosociety.org/bas_speaker/abx_testing2.htm
Tube vs. Solid State - Most traditional, competently designed SS amps have better specs than tube amps. Lower distortion, flatter frequency response, better damping factor. Bob Cordell's demo/workshop at the show in NYC showed clearly that tube amps make excellent soft compressors. This has been noted for many years but the demonstration clearly makes the point. More about the demo that I attended:
http://blog.stereophile.com/he2007/051507works/
This might work well in cases where a speaker does not have graceful overload characteristics. Better to compress the signal first with the tube amp, then feed the more tolerable signal to the speaker. This is an example of the complexity of non-linear systems.
Vintage AR Speakers - It is clear that vintage AR speakers such as the AR-3a have defects in the on-axis response. Notching for example, either due to crossover issues or perhaps diffraction off the molding. Flat, or at least smooth, on axis response has been shown in studies to be one of the most important factors in speakers that are otherwise of comparable quality. The 3a's are certainly good in many ways, reasonably low distortion, wide frequency response, etc. Perhaps these characteristics are more important to some. Many who favor the 3a claim that it provides a spaciousness to the sound. I believe that the notching in the frequency response, contributes to this "spaciousness" and so while some may view it as a disadvantage, others find it pleasing - when bad is good. However, one has to wonder if they had a reference with comparable performance but without notching which one they would choose in a controlled listening test. I find the notching to add a veiling to the sound and do not like it in any way.
Here is an interesting situation where the addition of notching improves the listening experience. HRTFs are removed with in ear headphones, is it possible that we are conditioned to hear them and therefore the notched response sounds better?
http://www.linkwitzlab.com/reference_earphones.htm
Also interesting:
http://www.johncon.com/john/SSheadphoneAmp/
Polite comments are welcome. Trolls and thread trashers please stay out.
