Recording with VDAT at 32KHz

Tips and advice for getting the most from Scope. No questions here please.

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johndunn
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Recording with VDAT at 32KHz

Post by johndunn »

This may be old news, but I could find no info on it.

Although perhaps not the best for working with live sound, the 32KHz sample rate is fine if you are just doing synth music. You get a lot more synths, with little or no loss of sound quality - in fact an argument could be made that anything coming out of a synth > 16 KHz probably should be filtered out anyway. At any rate, this is how I need to do it until I spring for more Scope hardware. But recording at that SR is a problem.

The VDAT appears to not properly record at sample rate of 32KHz, it totally screws up the timing, going at about twice the real time rate and running out of the allocated disk space "tape" unless you set it to about double what you actually need. When it thinks the time is up, it stops.

So the work around is to just set the "tape" time to allocate twice as much disk space as you will need, and go ahead and record. Of course the time readout is totally wrong, but once you've recorded it and relocated back to 0, the VDAT somehow figures out it's running at 32KHz, not 44.1, and from that point on it gets the time display right.

What I've found works best is to just set the time to 2x, then record a dummy track, reset, and it's ready to go with the real recording.

The tape output is properly recorded as mono tracks at 32KHz sample rate, and will load into other programs properly. Once I've mixed down from the multitrack into 2 tracks (I use 2 VDATS, which works great), I then use Sound Forge to load the two mono tracks into a stereo file. From there it's an easy matter to trim the excess blank sppace at the ends, and resample (at the highest quality setting) to 44.1KHz. Since it's upsampling, there is no aliasing artifacts to worry about.
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Fede
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Re: Recording with VDAT at 32KHz

Post by Fede »

johndunn wrote:Since it's upsampling, there is no aliasing artifacts to worry about.
but interpolation.... :wink:

thanx for the tip
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dawman
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Post by dawman »

I only use VDAT @ 32bit.

It works great live also as a backing track for vocals, etc,

Perhaps w/ XITE-1 it will operate @ 96Khz. :wink:
Last edited by dawman on Wed May 14, 2008 12:29 pm, edited 1 time in total.
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garyb
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Post by garyb »

are you sure you don't mean 32bit?

32khz is kinda silly when the cd is going to be at 44.1khz......
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Post by dawman »

Yes Brotha' Man,

32bit integer, but playback @ 96K is what I would love to hear soon.

Even though I will have to remain in the Scope realm, I am certain that it's quality will shine through for synths or vocals.

But the conversion process does take away the " sheen " of VDAT sorry to say.
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johndunn
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Re: Recording with VDAT at 32KHz

Post by johndunn »

Fede wrote:
johndunn wrote:Since it's upsampling, there is no aliasing artifacts to worry about.
but interpolation.... :wink:

thanx for the tip
Fede
Right. No free lunch, perfection is not attainable and all that. But as I said I used the high setting in Sound Forge, and I can't hear the difference.

Actually, it turns out that if your end product is going to be an .mp3, the encoder in SF (and I assume others) seems to work equally well on a 32KHz sample rate as the 44.1. In both cases it produces a 44.1KHz .mp3, and they both sound the same. So in the final for Spideron, I just encoded the 32 KHz sample rate file. Less is more.
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johndunn
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Post by johndunn »

garyb wrote:are you sure you don't mean 32bit?

32khz is kinda silly when the cd is going to be at 44.1khz......
No, I meant 32KHz. It's not so silly when your monster .pro file won't load because it can't fit all those synths into the DSPs available. So, as I said in the OP, it's a reasonable tradeoff if one is only doing synths. For acoustic music, not so much.
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garyb
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Post by garyb »

sounds like you just need another card.....





:lol:


but seriously, for mp3s your solution makes perfect sense. anyway, it's the music we want. great music with mediocre sound quality(resolution) will always be better than mediocre music with fantastic sound quality....
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the19thbear
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Post by the19thbear »

HEAR HEAR! thin about rolling stones, beatles, bowie etc... crappy sound, amazing songs!
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garyb
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Post by garyb »

johndunn wrote:
garyb wrote:are you sure you don't mean 32bit?

32khz is kinda silly when the cd is going to be at 44.1khz......
No, I meant 32KHz. It's not so silly when your monster .pro file won't load because it can't fit all those synths into the DSPs available. So, as I said in the OP, it's a reasonable tradeoff if one is only doing synths. For acoustic music, not so much.
actually though, i wasn't speaking to you when i wrote that. i was answering another..... :lol:
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johndunn
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Post by johndunn »

garyb wrote:sounds like you just need another card.....

....
Indeed. And soon they probably will become available on the cheap as people upgrade to Xcite. But most of the motherboards today have only 2 PCI slots, and in a year or so even those will be going away.
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