Downsampling Phase mystery

[deutero]

I have a stereo guitar recording at 16bit/48khz with no phase problems*, but when I render the track to 16/44.1k I end up with terrible phase problems. The problem is also there if I change my interface output (within Live) to 44.1k.

I have found a workaround--rendering the track at its original sampling rate and then converting that file to Redbook with dBpoweramp--but I wonder if anyone could tell me why that problem would be there to begin with. I've been doing some research, but not finding any answers.




*fyi: mic 1 was a large-diaphragm condenser pointed just behind the soundhole about 6 inches away, mic 2 was a small-diaphragm condenser pointed down the neck from the nut

[Tone Deft]

is high quality mode turned on in the preferences? options-preferences-audio-sample rate

[deutero]

is high quality mode turned on in the preferences? options-preferences-audio-sample rate

Yeah, always.

[v00d00ppl]

always record at 44.1.......going from 48 to 44.1 is pitching down your sounds a bit.

[anamexis]

always record at 44.1.......going from 48 to 44.1 is pitching down your sounds a bit.

No, you're not. Live resamples, not repitches. Repitching would be ridiculous- things repitched 48 to 44.1 khz would be almost 10% longer (and ~1.5 semitones lower).

(Though if you want to see exactly what happens when you accidently repitch something 48 to 44.1 - check out this painful example)

It is, of course, still a bad idea to go between sample rates that aren't even multiples, like 48-96-192.

[djgroovy]

(Though if you want to see exactly what happens when you accidently repitch something 48 to 44.1 - check out this painful example)

Painful indeed!

[Superchibisan]

you need to dither my man.

get yourself a dithering plug and any time you render below 32 bit, add the dither. set it for the target bit rate you're rendering to.

[anamexis]

you need to dither my man.

get yourself a dithering plug and any time you render below 32 bit, add the dither. set it for the target bit rate you're rendering to.

He's changing sample rate, not bit depth.

(and Live has dithering built in)

[Superchibisan]

read that wrong!

yeah, sample rate will cause all kinds of problems. not sure how to fix that one.

[deutero]

Like I said, I found a workable solution, I just had Live render it at the original sampling rate and then converted the rendered track with another program--no problem there.

But I'm just a little mystified by the conversion problem within Live. Even working with the project within Live at the lower sampling rate the problem is there. The individual left and right guitar tracks sound fine on their own at 44.1k, but put together they start to cancel (within Live) on certain chords.

If you're interested in hearing the actual problem, the track is up here: http://soundcloud.com/piston/dont-try

The track is just a simple demo that I helped a friend with. We hadn't noticed that anything had changed until after uploading, just checked the tracks on a mono laptop speaker--oops!

So, like I said, the problem has been solved. I just don't understand what caused it in the first place. A problem with conversion calculations in Live's audio engine, perhaps?