Why do preamps have 192Khz/24bit DACs?? What are they used for?? The only digital signal that is high enough is DVD-A/SACD but those are not digital signals, they are already decoded. So what are they for?

Thanks

I'd like to know this too.

This has been asked before here, but still yet to be answered.

Outlaw never mentioned that these DACs 'upconvert' anything like CD's 16bit/44.1kHz signal into this (potentialy) tremendously smoother 24bit rate.

If they don't use the chips for that then I just don't see the point of 'em!?

By the way -nice name 'ScanSpeaker'. I've got Scan-Speaks in my Newform Research and think they're great!

DTS has 24 bit capabilities, DVD Audio Discs (DAD's; Chesky Records and a few others released these for a while) have 24 bit resolution, and also it helps smooth signals out that are not 24 bit originally.

Remember, any processor or decoder needs to run at a higher rate than the actual signal its decoding in order to maintain low distortion and less jitter and smoother response. Some pro-audio DAC's, ADC's, and processors can process at 32 bits. A 16 bit DAC may only put out around 14 or 15 bit resolution in real world applications, 20 bit DACs maybe 18-19 bits, etc. because of line noise, jitter, and other signal anomalies. The higher, the better so don't complain.

The specs. for the top of the line 24 bit/192 kHz Cirrus Logic DAC's they are using show that there is some sort of enhancement for 44.1 and 48 kHz digital signals too. Upsampling and waveform rounding?

Dan

[This message has been edited by Dan Hitchman (edited January 23, 2002).]

[This message has been edited by Dan Hitchman (edited January 23, 2002).]

But this chip can't decode DVD-A, or 24bit/96Khz DTS. It can't decode 20bit HDCD's either.

So unless it is upsampling, I don't see why it's so awesome?
I'm not saying it's not the best chip out there, I'm just trying to figure out what it can and can't do.

Dan, you wrote-

"The specs. for the top of the line 24 bit/192 kHz Cirrus Logic DAC's they are using show that there is some sort of enhancement for 44.1 and 48 kHz digital signals too. Upsampling and waveform rounding?"

So you're sure there's 'some sort' of enhancment to CD, DD/DTS data rates, but then you write 'upsampling and waveform rounding' with a question mark after it, like you don't know if that's what it's doing or not?

I guess either it is or it isn't. I'd just like to know which.

When you say, -"A 16 bit DAC may only put out around 14 or 15 bit resolution in real world applications, 20 bit DACs maybe 18-19 bits, etc. because of line noise, jitter, and other signal anomalies. The higher, the better so don't complain."

One, I hope you're not saying that I'm complaining.

Two, are you sure that the 'real world' lower bit output resolution of these DAC chips are that low, or do you mean entire systems (like the output of the Outlaw 950, versus it's Crystal DAC chips)?

I know Sound and Vision said that even most DVD-A and SACD players only output about 19bit res. tops, but those were the outputs from the players, and due to noise in the wiring, and power supply, stuff like that, and not tests directly from the DAC chip -which isn't a 'real world' test of course, but still the part I'm wondering about.

Maybe a useless point to bother about, but I'm trying to figure out just what up with this chip. It's the main brain in this puppy, and I'd just like to know what it's doing.

It may just be that it was more economical to buy and use 24/192 DACs than a 24/96 alternative.

Not sure where this thread is going but just to throw everyone off guard, doesn't the "kHz" mean the speed at which it's sampled? So if you're listening to a CD, and have a DAC that's rated at 192kHz, then in theory isn't it read at four times its sampled rate? Same thing with a DTS track that's rated at 96kHz and you have DAC rated at 192kHz then you're reading it at twice the sampled rate? "In theory" at least? Or am I totally wrong and off based? Oh, and to really throw everyone a curve, a 24/192 DAC isn't state of the art anymore, there are now 24/384 DACS that are in some preamps as we read this. Just a thought...

[This message has been edited by slacker (edited February 05, 2002).]

If you play back a DTS track recorded at 96 kHz at 192 kHz, the tempo will be twice as fast and everything will be shifted up one octave. Since this doesn't happen, I'm assuming that either the DAC can be switched into a 96 kHz mode, or they simply double every byte before sending it to the DAC.

Doen't it just mean that the DAC is capable of handling a 192 source, and therefore all sample rates below it?



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Nigel Pond
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I'd be surprised if it could handle any sample rate below 192 kHz. It probably has a certain number of set rates that it can sample at, as each rate will need its own clock. I'm just speculating here, but sample doubling would be a very easy way to get more rates without having the DAC support them directly.