I am an electronics engineer and software designer in the military aerospace avionics field by profession, and also an audiophile for more than 40 years. I formerly before retirement had a successful company, Magnan Cables Inc., marketing my own design of audio cables including interconnects (as for instance the well-known Magnan Type Vi interconnect), speaker cables and power cables.
Guaranteed to outrage the audio skeptics here, the following is a short essay on "tweaks" in high-end audio, an example of some of the technical material I referred to. Also, attached below is a technical white paper I wrote on my own cable design theory. Undoubtedly a lot of snarky comments will follow.
This subject is like the tip of the iceberg - looks small at first examination but actually huge.
I have found through long experience that these effects are definitively real and pervasive in audio, and at least partially can be corrected by various measures.
I have found the following list of "tweaks" or adjustment/correction techniques to be essential for great sound. Individually and collectively these modifications have improved the sound of my system more than any component upgrades such as new amplifiers, preamps, etc. I believe my findings are applicable and useful to audiophiles in general, but of course I cannot guarantee the same results given the great variation in personal taste and component design. Of course, audio skeptics ("meter reader" type engineers) will hear nothing or at least convince themselves that they hear nothing.
A prerequisite is that your system already has to be good enough in terms of resolution, imaging, etc. for these techniques to be of benefit.
This is just a partial and evolving list and only touches on a vast subject. One of the fascinations of audio is the complexity of the basic problem — attempting to reproduce recordings as realistically as possible in a home environment. The elements of the problem include electronics, psychoacoustics, acoustical engineering, mechanical engineering, physics (electromagnetics) and many other disciplines.
Theory
I believe that these measures work primarily through two interrelated mechanisms: by increasing the "time coherence" of the system, and by lowering the noise floor. In this context, to "improve time coherence" means to reduce the delay and smearing of sonic energy of a musical event over some period of time following the event. This "time smearing" phenomenon is inherent in the mechanical and electrical systems used for sound reproduction, and the ear-brain system is very sensitive to it. Interesting to note, with digital audio there also is what is called "pre-echo", a ringing propagated in the signal before the transient is encountered. This kind of smear is also poisonous sonically.
Electrical examples are skin effect or frequency-dependent phase shifting of signal current propagated through the interior of a wire and dielectric absorption in capacitors and cables. Mechanical / electrical examples are the time delayed and resonant behavior of speaker drivers and enclosures, flutter (rapid speed variations) in turntables and CD transports, and time smear induced in the phono cartridge output due to stylus contact-generated energy returned to the stylus after first being propagated into the tonearm and record. Interestingly, timing jitter in the CD playback serial digital data is caused both electrically and mechanically by vibration, and rapid speed variations in the transport drive mechanism.
Another example of vibration feedback-induced time smearing is the vibration of wires in cables due to sound pressures from the speakers and to electromotive forces induced by adjacent current-carrying wires.
Another form of mechanical vibration-induced time smearing is the fore-and-aft vibration of a speaker enclosure in response to forces on the driver voice coil. This is simply due to Newton’s law of action and reaction and occurs regardless of the rigidity and degree of damping of the enclosure. Simply placing a 15-20 pound lead weight on the top of the speaker improves clarity of sound considerably by reducing Doppler distortion due to the reactive fore-and-aft motion of the enclosure. Doppler distortion smears sonic energy over a range of frequencies (rather than time) and is inherent in all speaker designs. If a driver diaphragm is moving at both a low and a high frequency at the same time (say 50 and 5000 Hz), the higher frequency is modulated (distorted) by the lower frequency due to the Doppler effect. As the sound source approaches at some velocity its sound is shifted up in frequency proportionately to the speed of approach, and vice versa for the sound source moving away from the listener. This effect "frequency smears" the output of all speakers, with the effect worsening with decreasing efficiency, smaller radiating area and 2-way designs. Of course the weights also improve performance by increasing the damping of cabinet resonance.
The common effect of all these and many other time and frequency smearing mechanisms is a massive perceived blurring, smearing, flattening and veiling of the sonic "picture", along with various tonal imbalances such as overbrightness and bass boominess or looseness.
The items listed below are really more than tweaks — they partially correct fundamental problems such as time smear and RF induced noise that no new improved electronics or speakers can address. As a general observation, each of these techniques achieves unique improvements, which cannot be produced by other tweaks.
The following observations are very important and should be kept in mind when considering "tweaks". The less revealing or resolved the system already is, the less impact the addition of a single modification or tweak will make. Of course, "revealing" doesn’t mean expensive — the transparency, resolution and musical naturalness of a system are more dependent on the quality of setup and tweaking than expense of components. This means that the first few modifications may only slightly improve the sound, but as the system’s resolution gets better and better, subsequent "tweaks" become more and more dramatic in their effect. Basically, the ear/brain system can perceive very small amounts of time smear or incoherence. If a given system mod or "tweak" reduces time smear by x amount and the system initially has 10x time distortions, there is little improvement. If the system is better, with only 2x distortion, the same tweak transforms the sound because it doubles the resolution by halving the time distortion.
My overall tweak technique list keeps expanding, but this is it for now. It is hard to give a relative ranking of all those items, but I have found that as a group the AC power purification techniques make the greatest improvement. Your comments and questions are welcome.
List of Techniques
Power line shunt or parallel filters
Do-it Yourself AC Filtering
Power conditioners
Dedicated earth ground
Ferrite RFI blockers
Turn Off and Unplug
Other Noise and Hum Reduction Techniques
Power Cables
Interconnects
Speaker Cables
Devices designed to correct CD digital errors
Component support and damping
Special component feet
Improved passive parts
Parallel RFI filtering at speaker input
Antistatic sprays
