I think it is a side effect of a wide dynamic range. The solution in the analog domain is to stick a compresser/limiter into the audio signal path. Behringer makes good inexpensive ones, albiet slightly more expensive than a Roku. Compression/Limiting is not too difficult to implement in software, so I am hoping that eventually something like this will be built into the Roku. Other companies that make them include DBX, Alesis and other. Prices seem to range from $69 to over $3000 and all are targeted at recording studios and sound system installations. I can't find any that are targeted at the consumer market. You might consider dropping into your local music store to see if you can find a stereo compressor/limiter on the cheap or used.
A volume control won't really help with this area - you will still be turning the volume up and down like I do, but using a compressor to lower the peak volumes should help. You have to play with the settings to get it just right.
- Joel
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