The difference between subjective sound qualities of an Audio system vs. the measured performance is the subject of much debate among both Music Lovers and Audio professionals alike. While the typical Engineer type will dismiss any claim of superior sonic performance of one Audio component over another of similar measured performance (The All Amplifiers sound alike camp) and the real or perceived quality of any given Audio component over another by Audiophiles have gone on for decades and as a result have created a nitch market for the Audiophile Press to respond to the concerns of Music lovers that claim to hear substantial differences between seemingly similar components. Magazines like the Absolute sound and stereophile have taken these concerns to heart and as such have flourished longer than the at one time more mainstream of audio rags like Stereo review and High Fidelity. The latter have been perceived as nothing more than long advertisements for the Audio manufactures that advertised with them. The claim that stereo Review never gave a bad review is just one reason Audiophiles have abandoned these and flocked in droves to the once underground press.
Like any revolution the Subjective perception of sound quality of High fidelity components that seam to defy subjective specifications have caught the attention of the professional Audio community and as a result a lot of research is now directed towards the reason differing components that measure more or less identical of so close as to be unheard by the ears of mere mortals. I have also noticed that even untrained listeners can differentiate between components that perform so well as to make the sanity of anyone that would say any audible difference between the two come into question.
Take the continued discussions hear regarding Op Amps, in theory there should be no difference in sound quality between the Burr Brown OPA-627 and the quite similar Analog device AD-8610. This really gets hard for some engineering types to understand since once ether of these two devices is placed in an Amplifier circuit they will measure virtually identical within the audio range. Yet they are perceived almost universally by most members of this forum as possessing slightly different sound.
Consider the fact that Op amps are talked about as having differing qualities in the bass reproduction even when both are operated in a Direct coupled configuration. How can this be the case most Engineering types would say as they leave the conversation laughing in utter disbelief, citing the ruller flat frequency and power response all the way down to Direct current? Now consider that most headphones and loudspeakers can not even remotely approach a flat frequency response down to DC.
The software industry has tried to take advantage of this and is working on instrumentation that hopefully will quantify the measured results to listener preferences
http://www.alma.org/Http_Pages/ANv5_2.pdf
http://www.mts.com/nvd/Software/pdf/...54_EOL_NVH.pdf
http://www.sae.org/calendar/nvc/ws-wed-sounda.pdf
http://www.picotech.com/applications...tml#amplifiers
http://www.lecroy.com/tm/library/LAB...20/default.asp
The Audio engineering Society has devoted quite a lot of articles dealing with the performance and sound quality in Audio Amplifiers.
http://www.aes-singapore.org/feb_6_1998.htm
http://www.aes.org/standards/b_pub/aes20-1996.pdf
The David Burning Company has quite a unique design philosophy regarding Amplifier design.
http://www.meta-gizmo.com/Tri/otlology/BERNINGS.htm
Its Audio quality research project has some interesting articles on Audio quality however more towards Digital telecom use than Audiophile however still interesting to read
http://www.its.bldrdoc.gov/home/prog...udio/audio.htm
http://www.its.bldrdoc.gov/home/programs/audio/subj.htm
Stereophile has a quite lengthy article on subjective sound impressions as one would expect from the rag that started all this talk of subjective sound quality.
http://www.stereophile.com/showarchives.cgi?190:
Simple op amp based headphone Amplifiers p Spice testing is a grate tutorial on what we hear love most. This is a tutorial on using p spice to simulate the parameters of op amp based headphone Amplifiers.
http://www.beigebag.com/case_amp1.htm P Spice intro
http://www.beigebag.com/case_amp2.htm Distortion
http://www.beigebag.com/case_amp3.htm Measuring Input & output Impedance
http://www.beigebag.com/case_amp4.htm maximum power output
http://www.beigebag.com/case_amp5.htm Power Supply Rejection Ratio
http://www.beigebag.com/case_amp6.htm open-loop gain
A great book for those that of us that are into High end Audio DIY projects available at amazon.com titled The Audiophile's Project Sourcebook review at
http://book.realbuy.ws/0071379290.html
also remember if you use the amazon.com link on Head-fi front page you will be supporting Head-fi
http://www.amazon.com/exec/obidos/tg...lance&n=507846
Those that love Tubes will surly like this site Do I need to make a disclaimer hear? I am not a Tube fan and I do not believe tubes are a superior Amplifying Device however some people do and so for those that just love thermionic valves devices.
http://www.allaboutcircuits.com/vol_3/chpt_13/12.html
back to Solid state Circuits let us not forget the thermal distortion guy at his new web site
http://www.lavardin.com/aesE.html#AES
http://www.lavardin.com/index.html
http://peufeu.free.fr/audio/memory/
A App note from Maxium regarding Bridged Amplifiers or BTL (Bridge to load) Noise and distortions and gasp class D Amps however good treatment of output stages
http://www.maxim-ic.com/appnotes.cfm...ber/1122/ln/en
http://pdfserv.maxim-ic.com/en/an/AN1760.pdf
Soundstage magazine describing how thay test Amplifiers
http://www.soundstagemagazine.com/me...amplifiers.htm
for the novice the How things work is a great site to understand almost anything hear is a link directly related to amplifiers.
http://howthingswork.virginia.edu/audio_amplifiers.html
Well I hope you are not now more confused that you were prior to reading this post however you should be more enlightened with respect to the differing conflicts that arise when trying to design an Audio component that not only sounds good but also measures well so as to satisfy both the technocrat as well as the Artist among you.
Subjective vs measurements in the perception of sound quality
Linear Mode
