To gain some headroom what do you guys suggest? Lowering input source from Volume Limit or the channel output?
6 comments
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HiFiBerry team If you're talking about any DSP calculations, you don't need to lower the input volume. Internally there are >30dB headroom for a full-range signal which should be enough for most calculations. Just make sure that the signal on the output doesn't clip.
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Matt I'm asking because I need to boost some frequencies and REW says to add some db for headroom.
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HiFiBerry team If you need to boost frequencies, you should reduce the overall volume by the maximum boost you want to implement.
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HiFiBerry team You can do this also on the output.
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NEO Dan When accounting for headroom if I have two relatively close filters that are something like +10 and -10 dB but the net result is a few dB of boost, is it only the final boost that I need to account for.
Is there any issue with having large value filters interacting/overlap?
If I go into the web interface Sound>Volume Limit and make an adjustment to cover my boost will that keep me out of digital clipping with a source that theoretically makes a -0dB unclipped input?
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HiFiBerry team Internally there is a at least 4 bit headroom. Therefore adding 10Db and then substracting it again is not a problem.
In the web interface, just make sure there is nothing above 0dB. However, in reality your will never have full range signals in the mid and high frequencies. Therefore filters that add some db in these ranges are usually not a problem.