[Siz.]

DSD simply adds softness to the sound ... It's the equivalent of putting everything into soft focus.

Rob,

Re your comments about DSD, it it possible that whether or not a SACD file gives a better result than the redbook PCM version depends on the DAC?

Sampling Theory says that an ideal dac could in principle reconstruct the original signal from a RBCD. M-scaler tech approaches this ideal, and does an excellent job with RB; less sophistated DACs, not so much and (all else being equal) might benefit from being fed a higher sample rate file.

If this is right (correct me if I am wrong) is it possible that a SACD version sounds better than the RBCD using a Hugo2 whereas the converse is true when using Mscaler/Dave?

 

[Rob Watts]

Yes agreed, a DSD file will probably sound better than PCM with a modest (by that I mean non WTA and with a regular DAC chip) with a DSD optimised DAC. But I certainly wouldn't include a Hugo 2 into that - PCM is much better than DSD with Hugo 2. OK PCM is brighter, but it's so much more transparent and varied - you get much closer to the original performance, and to me it's much more emotionally satisfying.

DSD is format limited, but PCM is conversion limited. Having said that, DSD to analogue is extremely difficult to do; it's impossible to maintain the original digital performance without adding significant distortion and noise by using direct low pass filtering methods. Then you also have the very complex analogue filtering to do as well to remove the huge out of band noise.

 

[474194]

^^^

I had a difficult time believing that PCM > DSD until I changed my Music Source to a Music Streamer/Renderer w/ Lifatec Glass Optical. Even when I was using a Lifatec Plastic Optical, I noticed the difference. I even contacted Lifatec on how to return the Glass Optical because it was so satisfying with $6 Plastic. After that honeymoon, I switched back to Lifatec Glass Optical and never turned back. For I, source matters as well as Glass Optical. The Lifatec Glass Optical is actually very pliable and suitable for portable use. It uses OptiSilk tech which handles and feels like silk is some ways making it extremely flexible.

I'm only in this hobby for mobility and don't want to be confined to one space, so my options are limited. Fortunately, I discovered a Raspberry Pi + HiFiBerry solution for my mobile needs:

I control via iPhone using the iPeng app (German Developer) which always maintained a 4.5+ rating since it released during the iPhone Gen1:

https://apps.apple.com/us/app/ipeng/id767266886

http://penguinlovesmusic.de/ipeng-8/

The entire Raspberry Pi OS is loaded in RAM at boot. I also set 'Now Playing' tracks to load entirely in RAM before executing. Here's the AudiophileOptimizer developer that does something similar with his product:

https://audiophilestyle.com/forums/...-windows-server-20162019-configuration-guide/

For those who don't know, RAMdisk is one of the most high-performance methods for audiophiles in the world, and although I've never read anything about it in this forum and only have a personal friend who has tested before me, I've read a lot, a lot , much information in international scope, where it seems that the theme is more evolved. Reducing latency and high throughput is only a small part of the benefits. If that weren't enough, I've never heard any "original" setup, with SSD, SD card, M.2, or anything else, that delivers audio quality as good as RAMdisk. For me, it's the best, but what I don't know is if there are different RAM models that deliver different sonorities (Corsair vs. Kingston; Kingston vs. Crucial; Corsair vs. GSkill; e.g.).

Naim and Bryston utilise Raspberry Pi + HiFiBerry for some of their respective products at > $1K where if you know what you are doing you can build for < $100 to start off without 3rd party upgrades:

The Bryston BDP-Pi digital music players let you hear a perfect replica of high resolution studio masters with incredible detail and breathtaking realism.

https://www.moon-audio.com/bryston-bdp-pi-digital-player.html

So having this available in a portable form that I could power with Anker battery packs is quite amazing to me. And then throw in a wireless UI that's scalable to Apple's upcoming mini/micro LED screens/watches==heaven.

Naim and Bryston just puts everything in a box with desktop components, brand it, make it look pretty and sell at a high price. I go simple with no Ethernet, de-solder coax, barebones case, Anker battery, etc.

Now I'm a PCM > DSD believer. That's why I want to attempt to try to extract great masters from the RB layers off SACDs if it's not hopeless.

The Hugo2 is an entirely different beast with the right RF-free optical optimised Music Source. Many thanks RW for your valuable lessons. Hoping to try with Mojo as next project. Cheers M8.

 

[474194]

I'm loving the depth on the Hugo2 via optical:

I am getting rather different sound from coax and USB inputs with the latter sounding better, what’s the reason for this?

It’s complicated and depends upon a number of factors - principally the amount of RF noise injected into the Mojo, and the amount of correlated noise that gets in. It will depend upon the source device as to which sounds best. My preference is optical, as this has the smoothest sound quality and best depth, as it does not suffer from both of the aforementioned problems.

http://the-ear.net/how-to/rob-watts-chord-mojo-tech
Still can't believe I'm running a portable optical source on par with the Ambre:

https://metrumacoustics.com/product/ambre/

Ambre is nice as it can run the same OS (piCorePlayer) that I'm running on the Raspberry Pi. AC power though...

 

[musickid]

Hello Rob,

I know you recently mentioned you had good results using your low power motorola phone to stream music. You also mentioned before that only a windows laptop with windows drivers can effectively handle errors in the packets of audio data being transmitted. Is this a limitation with a low power non windows device like a mobile phone? Finally when considering windows drivers and usb audio protocol does this apply to any streaming service or music player or can the player override this usb protocol. For example roon use a purple light signal path to confirm bit perfect delivery of the music file to the dac.

Many thanks MK.

 

[Rob Watts]

Yes technically Windows is more robust, but the reality is that regular USB data error rates are so low with a certified type 2 cable that it's not something to be worried about - data errors are very obvious as clicks and dropouts whilst doing DSD via DoP. That's something that in practice one doesn't see.

 

[musickid]

Hi Rob,

A small point came to mind. When conducting a bit perfect audio test the intention is to determine whether the music file is being delivered from source to dac intact and not missing any information. With DSD via DoP and passing this through a chord dac any imperfection in the file would manifest itself as clicks and dropouts even though this is extremely rare as you said.

What would happen if the same music file already confirmed as bit perfect after passing through a chord dac and on passing the same bit perfect music file through a poorly designed dac you hear dropouts. So my question is within the field of dac design and testing is the bit perfect test ever carried out to determine the integrity of the dac and not the music file itself itself?

 

[Rob Watts]

I can't really comment upon other designers and manufacturers as I simply don't know.

But, if you do a test for a long period, with averaging, like on an FFT, then it's immediately apparent when you get any type of bit error, as the noise floor will rise. Data errors are easy to see, and easy to hear for, so stop worrying about it as it's not in practice an issue for both USB or SPDIF. My experience with SPDIF is that if it happens then it's a huge issue - it's either all of the time with constant noise and clicks, or never.

 

[474194]

Hi Sir Rob,

I figured you were on your way to the "Big City"... Good luck with launch!

I picked up a Mojo for the holiday price for general purpose use (Videos, Gaming, audiobooks, etc.), but not opening the shipping package until after the launch. Depending on what is launched, I will either keep or get store credit in exchange for any interesting new Chord product.

No need to comment if it's too sensitive an issue. If I keep the Mojo, I plan to insert a USB IR Receiver programmed to receive and transmit Chord remote codes. I figure the Chord remote codes are one single standardised Chord code across all models. I also figure the underlying OS has remote code embedded unless specifically removed.

Slight chance this will work?

Thanks!

 

[HeeBroG]

Hi Rob,

A small point came to mind. When conducting a bit perfect audio test the intention is to determine whether the music file is being delivered from source to dac intact and not missing any information. With DSD via DoP and passing this through a chord dac any imperfection in the file would manifest itself as clicks and dropouts even though this is extremely rare as you said.

What would happen if the same music file already confirmed as bit perfect after passing through a chord dac and on passing the same bit perfect music file through a poorly designed dac you hear dropouts. So my question is within the field of dac design and testing is the bit perfect test ever carried out to determine the integrity of the dac and not the music file itself itself?

I might be completely wrong and there maybe a simple explanation for this but on a similar note; if "clicks and dropouts" are a measure of whether a file is bit perfect or not, how is it that there are no major audible aberrations when DSP/Convolution filters are introduced via a player like ROON?
The file is altered somehow and yet the DAC plays it fine. Perhaps something like this happens on the noise (EMI/RFI) front where the file is altered but not so profoundly as to cause a click/pop but we lose depth or gain harshness.

 

[Triode User]

I might be completely wrong and there maybe a simple explanation for this but on a similar note; if "clicks and dropouts" are a measure of whether a file is bit perfect or not, how is it that there are no major audible aberrations when DSP/Convolution filters are introduced via a player like ROON?
The file is altered somehow and yet the DAC plays it fine. Perhaps something like this happens on the noise (EMI/RFI) front where the file is altered but not so profoundly as to cause a click/pop but we lose depth or gain harshness.

I don't know but is it possible perhaps to think of DSP generating a new digital file? I don't use DSP so this is just a guess.

EMI/RFI does not alter the digital file at all. It merely overlays an analogue rf noise signal on top of the digital signal. The digital signal gets processed into music and the overlaid rf noise sails on into the analogue stage of the DAC where it can cause intermodulation distortion which is heard as reduced sound quality.

 

[Whazzzup]

No dsp on roon works brilliantly

 

[Rob Watts]

Hi Sir Rob,

I figured you were on your way to the "Big City"... Good luck with launch!

I picked up a Mojo for the holiday price for general purpose use (Videos, Gaming, audiobooks, etc.), but not opening the shipping package until after the launch. Depending on what is launched, I will either keep or get store credit in exchange for any interesting new Chord product.

No need to comment if it's too sensitive an issue. If I keep the Mojo, I plan to insert a USB IR Receiver programmed to receive and transmit Chord remote codes. I figure the Chord remote codes are one single standardised Chord code across all models. I also figure the underlying OS has remote code embedded unless specifically removed.

Slight chance this will work?

Thanks!

Yes we use a standard RC5 type code for the remote.
I fly to NYC on Friday, looking forward to CanJam!

I might be completely wrong and there maybe a simple explanation for this but on a similar note; if "clicks and dropouts" are a measure of whether a file is bit perfect or not, how is it that there are no major audible aberrations when DSP/Convolution filters are introduced via a player like ROON?
The file is altered somehow and yet the DAC plays it fine. Perhaps something like this happens on the noise (EMI/RFI) front where the file is altered but not so profoundly as to cause a click/pop but we lose depth or gain harshness.

No properly designed DSP will not create clicks or pops, as the data is being manipulated in a linear way; but faulty data from USB is a non-linear manipulation of the data!

 

[musickid]

I remember going up the Empire States building at the age of 9 whilst on a family holiday. Safe journey Rob.

 

[xenoVa]

@Rob Watts
Hello
Is Chord Mojo 2 on the works ?