Home Theater Forum - View Single Post - Audible Component Differences...A Nousaine Story

Chu Gai · 05-13-2004, 03:52 PM

The following story was recounted by Tom Nousaine. So should you tweak?

Quote:

A few years ago I tested the idea that devices that cannot be differentiated by themselves may have audible consequence when used in series. So I constructed two systems one of which was decidedly what i called Tweak using an outboard DAC, a vacumn tube preamplifier, a high-end Bryston power amplifier, expensive networked Monster speaker cables, $100 a meter interconnects, spikes everywhere they would work, Teknisonic vibration dampers to isolate the speaker cables from the floor and very careful cable dress.

The other was definitely Geak with a 20 year old solid state preamplifier built from a low priced kit, a used $200 power amplifier, interconnects randomly drawn from a junk box, 16-gauge car speaker cable (zip cord) with a 6-foot length for one channel and a 25-foot length for the other with the cable wrapped around the power cords several times.

The digital outputs of a Marantz Cd-player drove the Tweak system and the analog ouputs of the same cd-player drove the Geak system.

Once installed I found the systems both had response that was within 0.2 dB of each other but the Tweak system had a 2-dB channel imbalance which I compensated with the balance control on the Geak system.

Using an ABX comparator I was unable to hear any difference between them myself. I then invited a number of enthusiasts one at a time to audition them A/B with programs that they had personally found to be the most revealing for finding audibility differences.

ALL of them said they thought they sounded different. But NONE of them were able to differentiate when nothing more than a blanket was covering the inputs on the rear of the PSB Stratus Mini speakers (reference device with measurements taken in the NRC) hiding which set of speaker wires were connected to the speakers.

Someone following this debate might then conclude that bias-controls obscure differences that were audible under sighted conditions. But actually all the sighted information, except the answer to the question, was always available. The ONLY factor introduced was the elimination of a bias mechanism, subjects are inclined to report differences that do not have audible source, that is known to have consequence.

In this experiment I tried to include every item that I had heard people report as having audible consequence, not directly tied to frequency response or other known audible atrifact, either by itself or in tandem.