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Why I never got that perfect null in difference testing part one

I set out to see what the difference between expensive analog interconnects and cheap ones were. My method was simple in essence. I would send a signal to a DAC, send the analog output over an interconnect, record that digitally with an ADC. Then repeat with a different cable. Take the two digital files and subtract one from the other using software. There was a long thread posted in the general forum about my attempts. I learned some things along the way and eventually could get consisten

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Why I never got that perfect null in difference testing part three

Timing in my compared files, how do I compare timing in files?   Clearly none were as much as one single sample off. I had figured out ways to align all files to the single bit. I put one second of silence at beginning and end while putting one bit in the middle of the silence to maximum in the test files. So just record a few seconds before and after. Then align the signals in Audacity and chop off the ends with single bit precision. When the clocks were locked no other obvious artifac

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Why I never got that perfect null in difference testing part two

Okay, so difference testing didn't result in perfect nulls with only thermal and flicker noise left. Why not? The most obvious answer is a difference in level between the two signals recorded. With null depths of more than 100 db it takes very little level difference to leave a bit of the music above the noise floor. So I sent simple two or three tone test signals through comparing them. Using the same equipment and cable changing nothing. Had left equipment on for minimum of three full d

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Trust your ears? Trust your measurements? Look to psycho-acoustics for help? Is the psychology of being human the most important thing?

I am going to quote Barrows here. It is a complete post on his careful methodology of listening. I quote because I think it is an excellent description of how to audition for differences in components. I agree with it completely. He was responding to Julf's question about how he listened carefully:   Well, thanks Julf... As far as listening goes, I suspect that each of us may find things we can do differently, that is, what works for me, may not be the same for you. But a few things: blin

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Rational audio....a subjectivist journey.

Rational Audio....a subjectivist journey.   I began audio as a rational consumer or so I thought. I didn't want to spend money that didn't provide additional performance. Mainly because I didn't have much to spend. I wondered for instance why those Magnepan speakers cost so much when they didn't go down below 50 hz and only went up to 15 khz. So many speakers went lower and higher with less power for less money. With my first real job came a chance to buy a good stereo. I purchased a receiver

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