[Mojo ideas]

computers may or may not have the processing ability higher than chord dacs but ,

1) any upsampling software would require to present the upsampled stream in a way to be acceptable by the dac that is decimation to  24/ 32 bit and certain maximum sample rate supported by the dac which is currently limited to 768khz and that too only for few dacs. inside the chord dacs there is no such limitation and stream is converted to much higher sampling rate in such a way which is directly "consumed" by the pulse array dac.

2) i am not expert but what i could gather from chord dacs thread that WTA algorithm uses much more parallel processing power in real time. computers might have more processing power but for computers it is not possible to process in parallel in real time and stream to the dacs for the simple reasons mentioned above ie due to the practical limitations of upsamplimg softwares .

3) chord dacs implement much more than just upsampling including sophisticated noise filtering too.

4) i have myself tested hq player upsampling with most demanding settings and to my ears bit perfect data to mojo sounded more natural than upsampled data fed to mojo though hq player.

5) even with best and most demanding sinc filter in hq player set to 768hz to mojo, the i7 processor of my laptop used only 7% or so cpu which means even after the highest possible useable upsampling in hq player there was nothing which demanded very high processing power and you can't go beyond that.

6) many people use hq player to process pcm to dsd256 or even above to feed their so called native dsd dacs which claim to handle the dsd stream natively with simple low pass filter. this pcm to dsd256 and above processing is most demanding for the computers and obviously is not needed for chord dacs as chord dacs process the dsd stream via an algorithm instead just low pass filtering .

7) i even resampled a 44.1khz file to 176.4khz in sony sound forge using izotope 64 bit resampler with highest settings, saved the file and played through mojo /hugo. the sound initially sounded a bit more open but after some time it became clear that it was not natural as compared to direct bit perfect transfer to mojo/hugo.

in fact somewhere in this forum rob watts himself has clarified on this matter.

Simply put they don't have anything like the raw processing that our Dacs have!

 

[Whazzzup]

Just take the comment that they wouldn't with a grain of salt

 

[elviscaprice]

   
4) i have myself tested hq player upsampling with most demanding settings and to my ears bit perfect data to mojo sounded more natural than upsampled data fed to mojo though hq player.
 
5) even with best and most demanding sinc filter in hq player set to 768hz to mojo, the i7 processor of my laptop used only 7% or so cpu which means even after the highest possible useable upsampling in hq player there was nothing which demanded very high processing power and you can't go beyond that.
 
.

Good to hear you find the Mojo better without being upsampled in HQP.  Others have said the opposite, including Miska who owns the Mojo.  Just reporting what they have found.  Myself, I find the Hugo just fine without any upsampling.

 

[chesebert]

Simply put they don't have anything like the raw processing that our Dacs have!

Don't think that's an accurate statement. Although the ability to customize data transfer is something very useful FPGA brings to the table. I would think the same filter and processing can be implemented with CPU or GPU - may not be as efficient, however.

 

[GreenBow]

 

Simply put they don't have anything like the raw processing that our Dacs have!

Don't think that's an accurate statement. Although the ability to customize data transfer is something very useful FPGA brings to the table. I would think the same filter and processing can be implemented with CPU or GPU - may not be as efficient, however.

 
A computer does not use the CPU or GPU to process sound. It uses the onboard DAC chip, which is usually Realtec. Chord put powerful processing into the DAC which other manufacturers or motherboard manufacturers generally do not.

 

[theveterans]

   
A computer does not use the CPU or GPU to process sound. It uses the onboard DAC chip, which is usually Realtec. Chord put powerful processing into the DAC which other manufacturers or motherboard manufacturers generally do not.

 
The poster might be referring to oversampling the files using a digital filter before sending to DAC which in this case is CPU dependent due to software processing (far less efficient than FPGA of course)

 

[rkt31]

  Good to hear you find the Mojo better without being upsampled in HQP.  Others have said the opposite, including Miska who owns the Mojo.  Just reporting what they have found.  Myself, I find the Hugo just fine without any upsampling.

i tried every possible filter settings in hq player and every possible rate from 2x ( 88.2khz) to upto 16x and each and every case bit perfect transfer to mojo was smoother.

 

[rkt31]

Simply put they don't have anything like the raw processing that our Dacs have!

yes, even if the computer has more processing power, any upsampling software can't use the full power simply because of the limitation of maximum rate supported by the dacs which is 32bit and 768khz. even if in near future sampling rate supported by the dac is increased to 32x of 44.1/48khz , software will not be able to use full processing power of pc. so there is not much sense in the thing that computer has more processing power than chord dacs.

 

[rkt31]

   
A computer does not use the CPU or GPU to process sound. It uses the onboard DAC chip, which is usually Realtec. Chord put powerful processing into the DAC which other manufacturers or motherboard manufacturers generally do not.

hq player and other upsampling softwares use the processing power of computer and output the upsampled data to external dac via usb out. almost all softwares have the provision of either sending the bit perfect data or upsampled data to external dac. foobar also has few upsampling plugins.  i found v upsampler to be very good. j river has its own 64 bit processing engine. out of all these i found hq player upsampling to be the best but even that is not improvement over bit perfect transfer to hugo or mojo. actually i had to try these upsampling software  when i didn't have my mojo and hugo for some time.

 

[chesebert]

   
A computer does not use the CPU or GPU to process sound. It uses the onboard DAC chip, which is usually Realtec. Chord put powerful processing into the DAC which other manufacturers or motherboard manufacturers generally do not.

I am obviously NOT talking about running a windows/mac program and output using an onboard DSP chip. I am talking about programming at a assembly level (or use existing low level IP) to implement FIR filter and conversion in a general purpose CPU. GPU can be used as well given the parallel nature of the processing. This would be a special purpose computer and will not likely have an operating system.

 

[Whazzzup]

I find HD USB 32 bit 384 fr fantastic on TT and Hugo. No issues no Problems, plug n play

 

[miketlse]

 
I am obviously NOT talking about running a windows/mac program and output using an onboard DSP chip. I am talking about programming at a assembly level (or use existing low level IP) to implement FIR filter and conversion in a general purpose CPU. GPU can be used as well given the parallel nature of the processing. This would be a special purpose computer and will not likely have an operating system.

 
It may have been obvious to you, as the author of the post, but it clearly was not obvious to the final readers of the post.
 
You then describe a special purpose computer, to perform this conversion of music files.
Such a computer is not going to be available to 99.9999% of the users of any DAC, so is irrelevant to the discussion that was taking place.
 
You might as well have said that there is no need to spend $15000 buying a DAVE, because you can get better performance if you buy a $0.5M Cray supercomputer, then develop the machine code yourself.
Chord will be quaking in their boots at the prospect!

 

[alubis]

I believe at the end of the day, it's just a preference. Some people prefer using hq player filter and noise shaper for upsampling, while some people prefer chord's.

 

[rkt31]

@alubis, as far as I know ,even after hq player's processing a lot more processing still is being done inside mojo even if you feed mojo with 768khz. so in a sense you can't bypass the processing of mojo.

 

[Jawed]

Chord's current DACs run at 104MHz in the conversion of digital to analogue:

http://www.6moons.com/audioreviews2/chord/2.html

Notice the two boxes called 4E Pulse Array DAC. Those are the 4 pulse array elements, one array for each channel. That's the section that converts the digital code into analogue.

104MHz is a lot more than 768KHz!