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Author Topic: Clipping problem - how to reduce output?  (Read 2779 times)

KMorley

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Clipping problem - how to reduce output?
« on: January 24, 2011, 10:40:13 am »

I use Media Center to listen to lossless sources (FLAC files) through a dedicated external DAC and my Sennheiser HD650 headphones. 

This combination produces great music, but there is one annoying issue.  On some music, I hear some distortion on high-frequency instruments (like a wire brush on a cymbal or top-hat).  Using the DSP Studio, I've traced this to the peak level of the music staying at 100%.

When I hear the distortion, I can use the equalizer to reduce the output to just below 100% and the problem completely goes away.  But I have to do that for each frequency band and that's inconvenient.  Is there some way to reduce the overall level for all frequencies at once?

Just to be clear, the distortion appears to be happening in Media Center and/or it's SPDIF interface with the DAC.  The distortion is not affected by the volume level of the headphone amp.

Thanks!
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Matt

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Re: Clipping problem - how to reduce output?
« Reply #1 on: January 24, 2011, 11:02:11 am »

I use Media Center to listen to lossless sources (FLAC files) through a dedicated external DAC and my Sennheiser HD650 headphones. 

This combination produces great music, but there is one annoying issue.  On some music, I hear some distortion on high-frequency instruments (like a wire brush on a cymbal or top-hat).  Using the DSP Studio, I've traced this to the peak level of the music staying at 100%.

When I hear the distortion, I can use the equalizer to reduce the output to just below 100% and the problem completely goes away.  But I have to do that for each frequency band and that's inconvenient.  Is there some way to reduce the overall level for all frequencies at once?

Just to be clear, the distortion appears to be happening in Media Center and/or it's SPDIF interface with the DAC.  The distortion is not affected by the volume level of the headphone amp.

Thanks!


There are two possibilities that I can think of:

1) There could be clipping in the original signal.
2) Some DSP is enabled that is overdriving slightly

You can turn down the pre-amp slider in the Equalizer to get a perfectly flat attenuation that would provide extra headroom if #2 is the issue.
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Matt Ashland, JRiver Media Center

KMorley

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Re: Clipping problem - how to reduce output?
« Reply #2 on: January 24, 2011, 11:17:12 am »

Thanks for the response - that's the solution I was looking for.

I didn't realize that the far left slider affected all channels/frequencies at one.  I thought it was just another frequency band until I actually READ the labels at the top of the slider...

Some music exhibits the problem worse than others.  For example, "Danger" on "Road to Escondido" by JJ Cale and Eric Clapton is really noticeable.  Reducing the pre-amp slider by 2.2db gets the peak level to just under 100% (hits 100% on peaks) and completely fixes the problem.

Is there some other setting that can automatically protect against this kind of overdrive depending on the source file?

Thanks!
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