23 Jan
2005
23 Jan
'05
1:40 a.m.
Lee Revell wrote:
thankyou very much - very clear and informative!
shayne
i've heard
a lot of negative stuff about creative's native (?) 48000Hz
sampling rate - not being too technically adept, i'm wondering what is
really going on ... is *everything* put in through the ac97 codec
(that's the input port, no?) sampled at that rate? what does this mean
if i'm always setting jack (without the patched alsa) to record at
44100Hz? i know that things start sounding funny if you record at 48000
and then playback/downsample to a different rate .....
The DSP runs at 48000 natively, and does hardware sample rate conversion
for all other rates. The exception is multichannel recording, which
only works at 16bit, 48000Hz, because you are directly capturing the
outputs of the internal DSP before it goes through any rate conversion.
Also, there is only one stereo sample rate converter for capture, while
for playback each of the 64 voices has its own SRC.
These hardware SRCs are good quality, because emu10k1 is really a
hardware synthesizer that also can do PCM, the exact same hardware is
used for pitch shifting by the synth as sample rate conversion for PCM.
In practice there are some bugs but these can be worked around in the
driver.
should i *always* be using 48000Hz when recording
on an emu10k1 card? if
so, what's the best way to get a finished project down to CD-style
44100Hz without making it sound wierd?
The best way to use this card is to run at 48000HZ and then when you are
done resample to 44100 using a high quality software resampler. OTOH,
if you are working with a bunch of 44100Hz samples, you can run JACK at
44100Hz, if it sounds good to you. Multichannel playback at 44100
should be supported eventually. Although, keep in mind the kX driver
doesn't support this yet, and they have docs from Creative. But you
won't get the multichannel recording functionality at this samplerate.
If you are using it for live recording or effects processing then you
should certainly run at 48000.
Lee