7.4. DSP

Changing the two options on the DSP page takes effect immediately, and stays that way regardless of whether you leave the dialog with the OK or Cancel button.

The sample rate converter type should be chosen to fit the resources of your computer, and provide the best affordable quality at the same time. So fire up top or something similar on a spare terminal, and start with the best converter. If your machine is not very new, this will consume huge amounts of CPU, and the playback will very likely be choppy. If this is the case, you will have to pick another converter. Fastest Sinc Interpolator is usable on today's most machines. If not, use Linear Interpolator instead of ZOH since both are blindingly fast, but linear is naturally much better than zero-order (constant hold). It should also be noted that the CPU usage of sample rate conversion is greatly affected by the difference between the two sample rates: upsampling 32k to 96k will be much more expensive than, say, upsampling from 44.1k to 48k.

Of course, sample rate conversion springs into action only when the output sample rate (the sample rate you specified in case of OSS or ALSA, or the sample rate the JACK server specified in case of JACK) does not match the sample rate of the track you are playing. A typical situation is when you have 44.1k files grabbed from CD and play back at 48k.