SPDIF setting

Quote from ckemper

You can cite me anytime you want!

I am an engineer for electrical sience, acoustics and digital signal processing.
I have yet to see a scientific test that 96 kHz makes a difference.
If there was such a positive result, it would be great!
Where can I read it?

But it's a myth already, since it's not cool to say "I cannot hear a difference".
The tests would be easy, but nobody is performing it. Stupid.

The myth is not even uncovered by journalists, they are probably afraid to loose their reputation.

Analog summing and the respective devices is another very expensive myth ...

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You should say this to SONY's engineer.

What's the story?

Bob Katz did these tests...

... and debunked it as a myth, largely due to bad filter technology in the early days of digital recording.

Nyqvist teorem does work, but it needs 'ideal' filters to remove audible artifacts.
In the early days, the filter technology could not handle this so at lower freq it would be audible, the solution to rise the sample freq just placed these artifacts above the human hearing.
And suddenly everyone thought that higher sampling freq = better sound...

These filter issues is now long gone and even budget AD/DA converters have filters that handles this.

But people still thinks higher sampling frequency gets a 'more natural sound'...

(disclaimer: this is what I got out of B Katz book: Mastering Audio)

Bob Katz is right.

Todays DA converters do not suffer from the neccessity for steep anti aliasing filters.
This is also why there should be no difference between 44.1 and 48 kHz.

This filter problem was solved at the time, when we read read "oversampling" or "Sigma-Delta" on our CD players. When was that again? Way back in the beginning of the 90's.

Still I read this old filter story in a german studio magazin this year!

Quote from ckemper

I am an engineer for electrical sience, acoustics and digital signal processing.
I have yet to see a scientific test that 96 kHz makes a difference.
If there was such a positive result, it would be great!

Christoph, as much as I respect your work and expertise ... here you're simply wrong, in a certain way.

You're the manufacturer and inventor of great synthesizers and an amazing guitar amp simulator, no doubt. But you're not in charge of planning and building audio studio environments. And this is something you should be very aware of, because it's not your job to tell people how to build and setup their studio environment. If someone decides to go 96kHz all the way, he will have good reasons to do so. Your only task would be to offer the appropriate connectivity of the hardware you sell. Your hardware is audio accessory and NOT the core of a studio environment.

Ok, you can also tell people that they should simply use sample rate converters to adapt to their specific studio setting ... but guess what: It's simply impossible because you decided that your "audio accessory" MUST be master in a digital environment. That's a terrible situation, really. The Kemper can't be the master clock in a whole studio setup. Can't imagine someone telling you otherwise. Analog is a way to avoid that problem, but then I have to ask myself: Why do you offer digital I/O at all ... or why don't you offer it the right way?

Anyway, as I said above. You can't tell people that they don't have to use anything other than 44.1kHz just because your device is limited to just that. Instead you should think about the huge interest shown in sample rate choice and S/PDIF slaving.

http://xiph.org/~xiphmont/demo/neil-young.html

regarding the sync issue
SPDIF is a consumer standard-its meant to sync 2 devices. If you want to use it in a setting with more than 2 devices you will need to apply Sample Rate conversion. This will degrade audioquality in a way much worse than a sampling rate difference between 44 and 48 ever could.
The way i use the Profiler is recording over SPDIF and then simply switching back to the internal clock of my DAW afterwards. Only takes a second.

Lightbox,

I did not tell anyone what to do.
I have explained the technical limitations of the Profiler.

Independent from that i have pointed out the status quo of science regarding the benefits of different sample rates.
This is not related to the limits of the Profiler. if we provided all sampling rates that are requested, this topic would still remain.
In this case I to testify that the sound quality of the Profiler would not benefit at all by any higher sampling rate.
I think it's a good habit to question the 'good reasons' to run double sampling rates in the absense of scientific proofs.
But it's a question still.

If you used a separate SRC, everything is possible, for sure! In this case the Profiler must be the master (!). The audio interface is the second master for the new sampling rate.

I don't know if an affordable Spdif SRC is available. Anyway, any modern stand-alone SRC would - while converting the rate - be able to convert a master signal to a slave

Quote from ckemper

What's the story?

It's called DSD.

By the way when will i be able to buy the small part that i need for my KPA?

Quote from lightbox

Analog is a way to avoid that problem, but then I have to ask myself: Why do you offer digital I/O at all ... or why don't you offer it the right way?

Define "the right way"

I've read a lot of the arguments on gearslutz and other forums about the benefits -- real or imaginary -- of using higher sample rates. I understand that more data is captured at higher sampling rates, which could be conjectured to mean that a sound is being captured more accurately.

On the other hand, I am an avid collector of music CDs and spend a lot of time listening to them. I can tell a difference between a CD and a "lossless" audio file. Even if the file is at 1920000 khz, it doesn't sound like the CD, which has a lot of elements in the sound, some super- or sub-aural. I can feel the notes that are captured.

This doesn't in any way imply that recording at a lower sample rate is inferior. But it does serve to remind us that higher sampling rates are not everything, imho.

Plus, I dig Engineer Kemper's thoughts on keeping costs down. If there is an imperative to record at a higher sampling rate, an external converter is probably the best option for a studio that records at higher sample rates.

Quote from nightlight

... If there is an imperative to record at a higher sampling rate, an external converter is probably the best option for a studio that records at higher sample rates.

There's no such thing like a sample rate converter that can by synchronized by a studio master clock AND an incoming S/PDIF signal at the same time, afaik. I don't know why CK said that would be possible, maybe I'm missing something here. If someone knows a device that can be slave to a studio master clock AND an incoming S/PDIF signal at the same time I would be happy if someone could point me to such a device.

PS: Just made a few phone calls because CK really made me wonder what's going on. But I was right. There's no sample rate converter that can be "mastered" from 2 sync sources. I would have been very surprised if this kind of magic existed. So no matter how many or which SRCs to put in between, the Kemper always has to be the master of the whole digital chain.

Quote from lightbox

There's no such thing like a sample rate converter that can by synchronized by a studio master clock AND an incoming S/PDIF signal at the same time, afaik. I don't know why CK said that would be possible, maybe I'm missing something here. If someone knows a device that can be slave to a studio master clock AND an incoming S/PDIF signal at the same time I would be happy if someone could point me to such a device.

PS: Just made a few phone calls because CK really made me wonder what's going on. But I was right. There's no sample rate converter that can be "mastered" from 2 sync sources. I would have been very surprised if this kind of magic existed. So no matter how many or which SRCs to put in between, the Kemper always has to be the master of the whole digital chain.

The Kemper's clock is not master as it is src'd/reclocked.

Quote from Christian

Those magic devices are called asynchronous SRCs. Some audio interfaces have it built in (the cheap ones mostly not). And Uncle Uli has a pretty widespread lifesaver for these cases:
http://www.behringer.com/EN/Products/SRC2496.aspx

For those allergic to Uncle Uli, I'm sure there are more expensive solutions out there, too.

Available for the princely sum of $200. Thanks for the heads up, Christian. I don't need one, but it's good information for future studio upgrade paths.

Quote from Christian

Those magic devices are called asynchronous SRCs. Some audio interfaces have it built in (the cheap ones mostly not). And Uncle Uli has a pretty widespread lifesaver for these cases:
http://www.behringer.com/EN/Products/SRC2496.aspx
For those allergic to Uncle Uli, I'm sure there are more expensive solutions out there, too.

I really don't know what to believe. I've talked to people that really should know and they tell me that it's not possible. And now you tell me that it is. Maybe you simply missed something? Of course you can change the sample rate from the Kemper using the Behringer SRC if you continue to use this 'Kemper-Behringer chain' as the sync source for your audio interface. But as far as I understand and know, you can't make the Kemper a slave just by using a Behringer SRC in between.

Quote from lightbox

I really don't know what to believe. I've talked to people that really should know and they tell me that it's not possible. And now you tell me that it is. Maybe you simply missed something? Of course you can change the sample rate from the Kemper using the Behringer SRC if you continue to use this 'Kemper-Behringer chain' as the sync source for your audio interface. But as far as I understand and know, you can't make the Kemper a slave just by using a Behringer SRC in between.

No, no! See, the Kemper is locked to its 44.1 khz sample rate. It sends this sample rate to the Behringer. Assume some other sample rate is being sent to the Behringer by two/three other devices. The behringer accepts these sample rates, converts these sample rates to anything from 44.1 khz to 96 khz and sends that sample rate to the interface. I think it can even slave to a sample rate set by the interface. So the Kemper is a master all by itself, with nothing slaving to it. It's just doing its job within its sample rate limitations.

Ok, I'm going to order the Behringer at Thomann and try, although the studio guy at Thomann was one of the people that told me it won't work. I can send it back within 30 days, so no risk to waste cash. If it works well, I've spent some extra money but we have a solution for this annoying problem.

Quote from lightbox

Ok, I'm going to order the Behringer at Thomann and try, although the studio guy at Thomann was one of the people that told me it won't work. I can send it back within 30 days, so no risk to waste cash. If it works well, I've spent some extra money but we have a solution for this annoying problem.

You, my man, have crazy gas. I'm jealous you're able to throw down the cash at such short notice

Quote from nightlight

You, my man, have crazy gas. I'm jealous you're able to throw down the cash at such short notice

Not so much GAS but this issue has really annoyed me from day one. I have to run 48kHz here and I don't want to waste analog inputs if I can avoid it. These 159 Euro won't kill me if it helps to make things work the way I need.