[vkvedam]

Quote:

What do you have, X ray computer? :T)
 
What about a few pieces of hardware that state they get 24/96 from the USB. One costs around 1100. I don't understand how they get more from what is being offered at the output of the USB. 
 

 
Nope, I've got a Super Computer. Haha 

It's got to be un-sampling, just the way Pico does I think. That is something I don't understand unless you've got your own software with it which allows transfer in 24/96.
 

 

[vkvedam]

Quote:

 
USB can do 24/96 just fine.  I've got an M-Audio Transit that does it.  On Windows, it needs drivers, as does any USB device that does anything over 16/48.  The stock windows drivers don't support anything higher than that.  MacOSX supports 24/96 with the stock drivers, depending on which USB receiver chip is in the device.

Well I've checked in midi properties and there is no option for 24/96 over USB, it's only available over optical. Where did you get that thing from? Or does the Mac OS detect what USB device it has got plugged in?

 

[EddieE]

From Meier Audio's write up for the hiface:
 
Transfer of audio-data through USB to a DAC is normally limited to 16bit / 48 kHz data maximum. Vista and WINDOWS7 principly allow for data rates upto 24bit / 96 kHz but the USB-ports of most DAC units do not accept these rates yet.
 
And further down in his write up for the Nuforce ICON HDP:
 
This fine headphone amplifier has a built-in DAC and has analog inputs, coaxial and optical digital inputs as well as an USB-input (which accepts upto 24bit / 96kHz!). 
 
Really annoying that more DACs don't allow for 24bit through USB, since it is clearly possible.
 
Source: http://www.meier-audio.homepage.t-online.de/

 

[jamato8]

If the Mac OS X allows for 24/96 over the USB how do you rip it to the hard drive if the only record option is 16/48? 

 

[mrspeakers]

The 16/48KHz is a function of the TI chip, and use of USB 1.0 to avoid custom drivers.  Limiting to 48KHz via the TI chip is because the USB 1.0 can't support full bandwidth.  I'm a bit fuzzy on this next part, so corrections are welcome, but I think this is because the 1.0 is used to force a synchronous USB transfer, as the assumption has been asynch transfers create to much jitter and degrade audio.  For devices that don't have a quality internal clock or seriuos jitter reduction and rely on cheap TI USB chips to either be the DAC or to directly drive the DAC, this is an issue.
 
CEnterance makes the DACPort which uses adaptive transfers instead of synchronous but has a strong buffer to eliminate jitter.  I believe tey use the USB 2.0 interface in an adaptive mode to get support for 24/96 over USB.  By having strong buffering and jitter reduction/re-clocking in the device, the vagaries of adaptive transfers on jitter are eliminated and yet no driver is used so it's user friendly and reliable.  Probably, the D12 could have used a different interface than the TI chip, since CEntrance has proven you don't need synchronous transfer to get great sound if your circuitry is good at reclocking.  
 
The D12 has a TI USB chip which sets the limit on USB input to 48KHz.  The TI also has a DAC, but it appears it's not used, instead I infer the D12 sends S/PDIF recovered from the USB to the Cirrus CS8416 receiver which reclocks and outputs to the DAC.  The CS allows the S/PDIF from Toslink to be used for higher bitrate audio.  
 
Using the CS chip to reclock everything is probably part of why this sounds so darn good.  The CS chip says "It has an extremely low-jitter clock-recovery mechanism that yields a very clean recovered clock from the incoming audio stream."  It'd be interesting to see how accurate the recovered clock is, or if the D12 simply has it's own clock.  
 
Anyone peak at the board to look for a clock yet?
 
 

 

[Mad Max]

Isn't USB 1.0's bandwidth supposed to be overkill for 24/192?  Then 2.0 even more - the problem is supposed to be in the OS drivers, no?
Stuff like this pop up months after I read the thread on the subject and then I can't find the dang thread again.

 

[jamato8]

Yes there are a couple of sources for chips that can do 24/96 on USB but I still don't see how to rip a disc to a hard drive on a mac and have the resulting information 24/96. 
 
I do have a couple of downloads that are 24/96 that I use on optical but they were downloaded while I was in the states (purchased there as a download) and they sound excellent but how do you do this inside of the computer when all that is shown is 16/48 for recording or burning?

 

[Mad Max]

I was just talking about playback.  Recording is something else.  I know in windows you can burn/rip 24/96 to/from a DVD with the right software (I've ripped two DVD-A albums).  No way for you to get past the OS' processing layers and what not?  There might be some third-party utilities that can help you, but I wouldn't know.

 

[mrspeakers]

Quote:

Isn't USB 1.0's bandwidth supposed to be overkill for 24/192?  Then 2.0 even more - the problem is supposed to be in the OS drivers, no?
Stuff like this pop up months after I read the thread on the subject and then I can't find the dang thread again.

USB has bandwidth for 12Mbps, 192K/24 consumes 9,216,00bps, which is pretty close to full usage, and assuming latency, interrupts, etc. probably is not an easy load for USB 1, and definitely couldn't handle simultaneous I/O.  USB 2 does 480Mbps which obviously is an easy fit...  
 
So USB 1 is definitely NOT overkill, it's really close to the limit for 96KHz bi-directional, which is probably what a lot of chipmakers target, so for cost and reliability they shoot lower.  
 
Also (my assumption, USB guru may correct) I believe the 12 Mbps is for asynchronous and as I mentioned, conventional wisdom was that to minimize jitter you needed synchronous transmission, which will usually reduce bandwidth.  For most users these days, they have 256K audio, not even CD, so the volume market, which is what chip people care about, has little need for 24/96, and from a marketing perspective probably a good call though being interested in high-end I think it's deplorable.
 
There is a USB 2.0 audio device class, and I looked and there are a couple of chips that purport to support this, not sure why they don't have more uptake.  Probably these are in the more expensive desktop units that have high-speed 96 or 192K USB interfaces.
 
Bottom line, this explains why the D12 USB interface is limited to 48K, and why it still sounds great over USB is the jitter-reduction of the CS chip.  For the pricepoint of this device, using a pricier USB chip probably cost more than offering the optical interface, wouldn't yield sonic benefts, and would have pushed the price over $300.  

 

 

[mrspeakers]

Quote:

Yes there are a couple of sources for chips that can do 24/96 on USB but I still don't see how to rip a disc to a hard drive on a mac and have the resulting information 24/96. 
 
I do have a couple of downloads that are 24/96 that I use on optical but they were downloaded while I was in the states (purchased there as a download) and they sound excellent but how do you do this inside of the computer when all that is shown is 16/48 for recording or burning?

Could you clarify your question?  Are you trying to rip SACD or something?  If only regular CD, it'd actually degrade your sound quality to convert to a higher sampling rate.  
 
If you set the optical out on a Mac to 24/96 I believe it outputs the native format without conversion, so CD audio will still output 16/44.1, for example.  I have only used optical for 24/96 and USB for CD-rate, so I haven't tested the 24/96 output using CD audio to check the sample rate and bit depth.  

 

[jamato8]

Quote:

Quote:

Yes there are a couple of sources for chips that can do 24/96 on USB but I still don't see how to rip a disc to a hard drive on a mac and have the resulting information 24/96. 
 
I do have a couple of downloads that are 24/96 that I use on optical but they were downloaded while I was in the states (purchased there as a download) and they sound excellent but how do you do this inside of the computer when all that is shown is 16/48 for recording or burning?

Could you clarify your question?  Are you trying to rip SACD or something?  If only regular CD, it'd actually degrade your sound quality to convert to a higher sampling rate.  
 
If you set the optical out on a Mac to 24/96 I believe it outputs the native format without conversion, so CD audio will still output 16/44.1, for example.  I have only used optical for 24/96 and USB for CD-rate, so I haven't tested the 24/96 output using CD audio to check the sample rate and bit depth.  

No, I don't upsample as I question how you can replace what the chip is programmed to guess at. Some people like it I don't. You can't rip SACD's but then I know you know that. 
 
I downloaded some FLAC files that are 24/96. 
 
Where do you adjust the optical output for bits and sampling rate on a Mac?
 

 

[pekingduck]

Go to System > Audio MIDI Setup
 
Quote:

 
I downloaded some FLAC files that are 24/96. 
 
Where do you adjust the optical output for bits and sampling rate on a Mac?
 

 

[jamato8]

I still can't find it. I have seen MIDI before but can't locate it under system or sound, which search shows it to be there but I can't locate it. 
 
Ok, I found it but only after a search but for some reason it isn't showing up unless I do a search and then I can configure it, which I did. 

 

[zheric]

Just got mine in today. Really happy with how quickly I got it, and they sent me one without the logo and text on the top like I requested. I only had a couple of minutes to try it out, but I went from cheap headphones/earphones straight to SRH840s and SE535s so hopefully I'll be able to appreciate my gear properly.

 

[mrspeakers]

Quote:

I still can't find it. I have seen MIDI before but can't locate it under system or sound, which search shows it to be there but I can't locate it. 
 
Ok, I found it but only after a search but for some reason it isn't showing up unless I do a search and then I can configure it, which I did. 

Hi Jam.  Easiest way: spotlight "Audio Midi Setup" and open the app.  It's not a control panel...  From their you can set bitrate and depth for each output option, and assign the audio output to be used for audio and system alerts (e.g. use midi for audio and internal speakers for system beeps).