"Official" Audyssey thread (FAQ in post #51779) - Page 2392 - AVS Forum
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post #71731 of 71737 Old Today, 01:46 PM
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soundcard output running REW sweep into one of the avr's RCA in's (let's say "CD source") then RCA outs on left or right channel into soundcard input, should give you a sufficient loopback to see what happens with changes AT the AVR level...

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post #71732 of 71737 Old Today, 01:58 PM
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A loopback might be a little tricky. Essentially you're amplifying the entire noise spectrum internally generated by the amp circuits. If the (pre)amp is set to anything less than unity gain, the signal would quickly fade to 0, while higher gain would amplify the signal to as high a voltage as the circuits could drive. I dunno what the resulting signal would actually look like.

REW might be a reasonable signal generator, since that part could be entirely in the digital domain. The quality of the signal it'd detect would depend on the quality of the audio inputs of the computer you're using. I don't know that I'd trust them not to be generating their own distortions, especially when driven by high frequencies. Any such distortion would generate spurious higher harmonics. It'd be a good place to start, though.

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post #71733 of 71737 Old Today, 02:01 PM
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Quote:
Originally Posted by Selden Ball View Post
A loopback might be a little tricky. Essentially you're amplifying the entire noise spectrum internally generated by the amp circuits. If the (pre)amp is set to anything less than unity gain, the signal would quickly fade to 0, while higher gain would amplify the signal to as high a voltage as the circuits could drive. I dunno what the resulting signal would actually look like.

REW might be a reasonable signal generator, since that part could be entirely in the digital domain. The quality of the signal it'd detect would depend on the quality of the audio inputs of the computer you're using. I don't know that I'd trust them not to be generating their own distortions, especially when driven by high frequencies. Any such distortion would generate spurious higher harmonics. It'd be a good place to start, though.
@Selden and beast

Yet, I still think the bottleneck in the loopback chain here would be the soundcard input itself. Most probably those s/cards are not so famous for their response at ultrasonics (like above 20 kHz).
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post #71734 of 71737 Old Today, 02:26 PM
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The best way would be to stay in the digital domain and have access to the final point via menu (with a couple of key strokes on the remote) right before the digital signal enters the DAC and see how the sampling rate in kHz changes with Audyssey on/off, Bass Mangement on/off, etc. Wishful thinking, I know.

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post #71735 of 71737 Old Today, 03:11 PM
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@Selden and beast

Yet, I still think the bottleneck in the loopback chain here would be the soundcard input itself. Most probably those s/cards are not so famous for their response at ultrasonics (like above 20 kHz).
Sure, but IIRC, my external soundcard I purchased initially for REW sweeps was pretty good on the loopback to well above 50khz. I don't have those loopback graphs anymore or I would post them, but you are correct, you definitely need a good soundcard and clean signal chain to make it right....

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post #71736 of 71737 Old Today, 04:17 PM
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Is it recommended to re-run XT32 calibration after putting in an area rug over a tile floor?
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post #71737 of 71737 Old Today, 04:49 PM
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I would say so, yes. A big area rug would almost certainly change the acoustics of the room, reducing reflections bouncing off the floor.

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