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      04-11-2012, 12:47 PM   #63
E30 Racer
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Drives: '11 1M, '09 335i M Sport
Join Date: Aug 2011
Location: Ohio

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Originally Posted by taibanl View Post
Why is the high level input, reportedly superior.
I'd be interested in the answer to this as well.

My HD600/4 has the same issues as reported above, but I've determined its an input signal issue (present even with the OE HiFi amp). The car is an E82 with HiFi + Technic harness adapter. Taking the front channels from the harness to the HD in conjunction with the low input setting (gains at min), I get noise. Switching to high voltage removes the noise but as mentioned above, it returns when the gains of the amp are turned up.

Recently I ran the front channels from the Technic harness into a Mosconi 6to8 DSP. This processor has low/high input settings as well. Interestingly, I ended up using a high voltage input configuration to the 6to8 and retained the low voltage setting at the input of the HD. Other combinations resulted in what sounded like a really compressed signal; very poor sound quality with an unnatural dynamic range.