AES/EBU? Would like to have a better understanding

[routlaw]

Out of curiosity last night I decided to play around with various connections from my ERC-4 to the XMC-1 built in DAC in Reference Mode. Having never used AES before I thought what the heck, I have a pair of Blue Jeans Belden 1800F laying around that are 110 ohm cables and very suitable from AES/EBU, which have also been used for years as analog balanced cables in my system. The results: immediately I was floored! Of all the digital cable chicanery I have messed around with over the years none of created such a profound affect, most of it very good (I think) but with one possible reservation. The bass grew by a noticeable amounts but after a period it occurred to me it might have also become a bit more bloated also. More time needs to be spent with this.

Experimenting with various SPDIF coax cables have always presented some changes, as have various USB paraphernalia and accessories, but nothing of the magnitude of the AES cable connection. 

This begs the question, what's is the deal with AES and why is it not more widely used then? Or perhaps it is and I'm not aware of it.

Its my understanding analog XLR cables should not be used in this domain due to an potential impedance mismatch, but this normally refers to signals in the megahertz category not the audio band of 20hz-20khz and if used this should only reduce the signal strength. But if implementing an analog cable into an AES setting for hifi equipment what detriment might it have in regards to sound quality? 

Thanks in advance for any insight into this subject.

[DYohn]

AES/EBU is simply a professional variant of S/PDIF. It is not more widely used because the connectors etc. are expensive.

[boomzilla]

Hi routlaw -

FWIW, I agree with you in your preference for the sound of AES/EBU.

[garbulky]

AES is balanced digital audio. But it shouldn't sound different. But I loved balance gear so thatsd what I would use if I had the choice!

[DYohn]

Dec 11, 2020 9:19:18 GMT -5 garbulky said:

AES is balanced digital audio. But it shouldn't sound different. But I loved balance gear so thatsd what I would use if I had the choice!

AES/EBU does use a differential signal on pins 2 and 3, but it is not really "balanced" in the same way that analog signals are. Here's some background: www.soundonsound.com/techniques/digital-interfacing

[AudioHTIT]

I always assumed the primary advantage of AES/EBU was distance, and I believe the spec calls for 100 meters, but I also remember hooking up audio from my first Mitsubishi HDTV via S/PDIF coax and getting a hum. I added an RCA / XLR adapter and went into the AES/EBU input of the AVR and no hum (probably lifted the ground), so it might have some unexpected benefits.

[garbulky]

routlaw for AES you should use 110 ohm AES cables.

[routlaw]

Thanks for all the replies and especially on the tutorial of digital connection DYohn . This was written in 2007 which in digital times and technology is light years away. USB as an interface probably was not around at this time. How much has changed since then?

So I wanted to take my experiments up another notch and tried the AES cable with my Holo Spring DAC last night and once again heard a very profound change. This is not something one has to A/B for comparison sake, its so obvious, at least on my system. However the audible results were not quite the same as the previous night using the built in DAC of the XMC-1. In both cases the presentation seemed noticeably smoother yet more detailed and dynamic. Perhaps jitter or lack of it with AES is the culprit? 

[DYohn]

Dec 11, 2020 12:41:30 GMT -5 routlaw said:

Thanks for all the replies and especially on the tutorial of digital connection DYohn . This was written in 2007 which in digital times and technology is light years away. USB as an interface probably was not around at this time. How much has changed since then?
;

USB was not designed as an audio interface.

-edit- Also, nothing in that article has changed that I know of.

[routlaw]

Digging in a bit further yesterday I decided to try my Mac Book Pro via Singxer SU-1 DDC outputting AES into both the Spring DAC as well as the XMC-1 built in DAC. The SU-1 can only be fed a USB input.

The Holo Spring DAC subjectively outperformed the XMC-1 in this configuration however both were significantly better than either a direct USB feed or an I2S feed into the Spring DAC. Likewise, coax just isn't in the same league either.

This begs a few questions. Given USB is thought to be the holy grail of digital transfer via computer, (note I'm not one of them) is it possible as some have inferred the Windows implementation of USB audio is really superior to what is available on the Mac platform? Please let's not get into a computer war of this question. I'm earnestly perplexed by these recent discoveries though.

Thanks. 

Also for anyone interested I can describe in detail what I hear differently implementing AES vs USB directly or USB>I2S. However I can't explain why there is such a difference. 

[DYohn]

Dec 12, 2020 15:27:34 GMT -5 routlaw said:

Also for anyone interested I can describe in detail what I hear differently implementing AES vs USB directly or USB>I2S. However I can't explain why there is such a difference. 

Most USB sucks for audio. AES/EBU is designed for audio.

[garbulky]

Dec 12, 2020 15:27:34 GMT -5 routlaw said:

Digging in a bit further yesterday I decided to try my Mac Book Pro via Singxer SU-1 DDC outputting AES into both the Spring DAC as well as the XMC-1 built in DAC. The SU-1 can only be fed a USB input.

The Holo Spring DAC subjectively outperformed the XMC-1 in this configuration however both were significantly better than either a direct USB feed or an I2S feed into the Spring DAC. Likewise, coax just isn't in the same league either.

This begs a few questions. Given USB is thought to be the holy grail of digital transfer via computer, (note I'm not one of them) is it possible as some have inferred the Windows implementation of USB audio is really superior to what is available on the Mac platform? Please let's not get into a computer war of this question. I'm earnestly perplexed by these recent discoveries though.

Thanks. 

Also for anyone interested I can describe in detail what I hear differently implementing AES vs USB directly or USB>I2S. However I can't explain why there is such a difference. 

I don't think USB was thought to be the holy grail. The main advantage that used to be talked about was that the new USB class 2 was asynchronous which significantly reduced jitter. The other advantage is that USB can transmit extremely high bitrates of audio like 32 bit audio and high bit rate DSD. On the other hand, I've had more glitches like stuttering audio or pops and clicks over USB. USB also uses a driver, though granted it is now built in to windows 10. But I remember the days when you had to install a driver. I also remember all kinds of complaints about the device being lost once the computer went to sleep etc. With things like coax and optical, you don't have it because there is no diver on the DAC side. The DAC simply receives the data. In the earlier days of USB, the USB interface didn't sound quite as good as the other interfaces too - though it still sounded extremely similar. The first USB interface I heard that I couldn't tell any difference at all between that and Optica/coaxl was the Mytek Liberty DAC.

So for me, USB is probably now in a very good state, but I am burned by older software glitches and stuff to want to try it again. Mainly because I have no need to. I just want my stuff to work right, no matter what I do to it. I don't want to mess around with installing drivers or things like that. For that reason, I use optical/coax/BNC connections.

[routlaw]

Dec 12, 2020 15:57:21 GMT -5 garbulky said:

Dec 12, 2020 15:27:34 GMT -5 routlaw said:

I don't think USB was thought to be the holy grail. The main advantage that used to be talked about was that the new USB class 2 was asynchronous which significantly reduced jitter. The other advantage is that USB can transmit extremely high bitrates of audio like 32 bit audio and high bit rate DSD. On the other hand, I've had more glitches like stuttering audio or pops and clicks over USB. USB also uses a driver, though granted it is now built in to windows 10. But I remember the days when you had to install a driver. I also remember all kinds of complaints about the device being lost once the computer went to sleep etc. With things like coax and optical, you don't have it because there is no diver on the DAC side. The DAC simply receives the data. In the earlier days of USB, the USB interface didn't sound quite as good as the other interfaces too - though it still sounded extremely similar. The first USB interface I heard that I couldn't tell any difference at all between that and Optica/coaxl was the Mytek Liberty DAC.

So for me, USB is probably now in a very good state, but I am burned by older software glitches and stuff to want to try it again. Mainly because I have no need to. I just want my stuff to work right, no matter what I do to it. I don't want to mess around with installing drivers or things like that. For that reason, I use optical/coax/BNC connections.

It might not be the holy grail but it surely seems to be the preferred format by any measure these days. One only has to consider the abundant supply of USB DAC's in the market. Having spent the last 20 years or so fooling around with computer based audio, at this point I'm about over it, similar to your experience presumably. The almost endless glitches and USB hang ups become untenable at times. Regarding the higher resolution possibilities over USB, you are correct but in my case I've yet to hear any improvements converting PCM to DSD or upsampling sample rates. Do they sound different, yes absolutely but not better to me yet others appear to be enamored with this. The point is this so called advantage is lost on me. Go figure.

This past year a great deal of my time has been spent either with vinyl or spinning cd's. I've gone so far as to converting high resolution downloads to 16/44.1 and burning to disc using DB Power Amp, which for interested has one of if not the best algorithms for sample rate conversions used in this manner. However at the risk of contradicting myself, yesterdays experience with USB feeding an SU-1 outputting to AES to either of my DAC's was an audio epiphany putting it mildly. 

Thanks