Combining different sample rates

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Can you think of a way to combine these two sources without resampling?

I'm going to be copying some music from video tape recorded with a PCM-F1
to CD. Most of these tapes have ambient channels recorded on the HiFi
audio tracks of the video tape.

I've aquired a PCM-601ES unit with digital output, but I understand that
it's 44.05593846 kHz.

I'll sample the analog tracks through my Cranesong Spider (best converters
I own) at true 44.1 kHz.

The front source is 44.056K. I don't have another clock I can set to that
rate and the 601 has no word clock output, so there's no way to send both
streams synched and clocked. Am I right?

My computer will accept both streams simultaneously through separate SPDIF
and Lightpipe inputs. I can then resample the back channels to 44.056 and
then just tell the file it's 44.1 without resampling. I don't need sample
accurate alignment of the front and back channels, and I don't think the
slight pitch change (0.1%) will bother anyone.

Archived from groups: rec.audio.pro (More info?)

In article <Xns963F5BB001E28gulfjoehotmailcom@207.69.189.191>,
Carey Carlan <gulfjoe@hotmail.com> wrote:
>Can you think of a way to combine these two sources without resampling?
>
>I'm going to be copying some music from video tape recorded with a PCM-F1
>to CD. Most of these tapes have ambient channels recorded on the HiFi
>audio tracks of the video tape.
>
>I've aquired a PCM-601ES unit with digital output, but I understand that
>it's 44.05593846 kHz.
>
>I'll sample the analog tracks through my Cranesong Spider (best converters
>I own) at true 44.1 kHz.

This is bad. The thing is that SRC is very hard to do with sample rates
that are extremely similar. This is probably the worst case scenario
for SRC.

>The front source is 44.056K. I don't have another clock I can set to that
>rate and the 601 has no word clock output, so there's no way to send both
>streams synched and clocked. Am I right?

Well, that's a question... if you COULD split the output of the 601 with
a DA, you would be able to use the S-PDIF signal as a reference clock.
The problem is just that it's going to be a lousy reference clock because
it'll be referenced to the data clock in the 601 which is not exactly good.

If you had an Apogee AD-1000, or some other converter that could sample
at 44.056, you could just use it to record the analogue tracks wild and
just expect that there might be a little drift here and there.

If you had a master reference clock that would lock to an external source,
like the Big Ben, I think you could use that to clean up the clock coming
out of the 601's S-PDIF connection before putting it into the Cranesong.

I think Audio Alchemy made a little reclocking box back in the late
eighties, and it sold for a couple hundred bucks when it was new. It took
a dirty S-PDIF input and give you a reasonably cleanly-clocked output.

The real question is how the Cranesong will deal with a lousy clock input,
and you should ask them that. They may have some solution that I haven't
thought of.

>My computer will accept both streams simultaneously through separate SPDIF
>and Lightpipe inputs. I can then resample the back channels to 44.056 and
>then just tell the file it's 44.1 without resampling. I don't need sample
>accurate alignment of the front and back channels, and I don't think the
>slight pitch change (0.1%) will bother anyone.

Alternatively, you could just take the rear channels, which I assume
are on the analogue tracks and which probably don't sound all that
wonderful anyway, and just run them through the SRC and see what
happens. They can't get all THAT much worse.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

daz[at]roughdiamondmarketing[dot]com wrote:

> why not record each at their own clock rate, save as 44.1 and then
> pitch shift the wrong one ?

In essence, that's what I recommended.

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kludge@panix.com (Scott Dorsey) wrote in
news48k5n$9st$1@panix2.panix.com:

> Well, that's a question... if you COULD split the output of the 601
> with a DA, you would be able to use the S-PDIF signal as a reference
> clock. The problem is just that it's going to be a lousy reference
> clock because it'll be referenced to the data clock in the 601 which
> is not exactly good.

That's the best idea I've heard so far. The 601 clock is no worse than the
signal recorded on the video hifi audio tracks. A bit of jitter really
won't mess that sound up much.

What kind of DA do I need? Would an active video splitter do it? (got one
of those).

> Alternatively, you could just take the rear channels, which I assume
> are on the analogue tracks and which probably don't sound all that
> wonderful anyway, and just run them through the SRC and see what
> happens. They can't get all THAT much worse.

I'll do that if I can't do anything else. I know that the Cranesong's
clock is better than the 601, so I'm going to have to fight drift.