AES/EBU interface help needed

Gadget

I have 4 x outboard rack fx processors which I am trying to connect digitally to my home recording setup.

All 4 have AES/EBU (or AES3 if you prefer) XLR i/o, so does anyone know of a suitable AES interface which I could either connect to the optical ADAT on my TC Electronic Studio Konnekt 48 audio interface, or connect to my Windows 10 PC via some other method? Ideally I want to be able to use each fx processor individually, or all at once.

For info, I currently do have 3 of them connected to my audio interface via a combination of SPDIF and optical Toslink (a couple via coax to optical converters), but am having some clocking issues when trying to use everything together, so I'm trying to lose the converters and simplify things.

I appreciate there are mega-expensive new pro studio solutions out there, but I'm trying to do this on a budget if I can, so I'm happy to re-purpose older solutions. Ultimatelythough, I am prepared to replace my interface with something more modern if necessary (up to around £2k).

Heartfeltdawn

What are the external fx units? 

Gadget

Heartfeltdawn said:

What are the external fx units? 

Axe FX III, Eventide Orville, Lexicon PCM81 and Two Notes Torpedo Studio, in a TC Studio Konnekt 48 audio interface.

octatonic

Gadget said:

I have 4 x outboard rack fx processors which I am trying to connect digitally to my home recording setup.

All 4 have AES/EBU (or AES3 if you prefer) XLR i/o, so does anyone know of a suitable AES interface which I could either connect to the optical ADAT on my TC Electronic Studio Konnekt 48 audio interface, or connect to my Windows 10 PC via some other method? Ideally I want to be able to use each fx processor individually, or all at once.

For info, I currently do have 3 of them connected to my audio interface via a combination of SPDIF and optical Toslink (a couple via coax to optical converters), but am having some clocking issues when trying to use everything together, so I'm trying to lose the converters and simplify things.

I appreciate there are mega-expensive new pro studio solutions out there, but I'm trying to do this on a budget if I can, so I'm happy to re-purpose older solutions. Ultimatelythough, I am prepared to replace my interface with something more modern if necessary (up to around £2k).

This is stuff I deal with day in, day out and I've done extensive testing on this specific topic.
If you want to save time, last paragraph has what I think you should do.

AES3 (AES/EBU) is a professional digital format.
The reason you are having issues is you are converting AES3 to S/PDIF and optical and it is just a big mess because you don't have any way to clock them properly. Professional studios will usually employ wordclock to keep multiple digital devices in sync but that needs to be planned properly.

The Axe FX III doesn't have wordclock, which is a serious limitation here and means you cannot do that. Or if you do it then the Axe FX III won't be part of it. The AFX is also fixed at 48kHz which is an annoying limitation. I've never understood why Cliff does that.

So, how are you connecting the equipment?
For instance, what is the clock master?
Please be descriptive.

If it is the TC unit then are you connecting the digital outs from that to the digital inputs to the devices as well as the digital outputs from the devices to the digital inputs of the TC unit?

The truth is that for 99% of people the converters in their audio interfaces are good enough and you don't need to be using the digital IO.
Don't believe me, try this.

1. Record the same signal from the Axe FX III into the TC via AES (or S/PDIF) and via analogue.
2. Time align them (because latency might be different over analogue vs digital, by 2-3 samples usually)
3. Flip the phase on one of the tracks and see how they cancel.

Here we do use digital outputs for some of the digital equipment, but the MTRX II audio interface has SRC on input and we use wordclock for any equipment that has it.

In your situation I'd buy a good quality 8 channel analogue to digital converter that supports ADAT (assuming you aren't already using the ADAT in your TC) and connect all the devices over analogue. I have an Apogee Rosetta 800 for sale soon, or there are loads of cheaper 8 channel converters that will do the job. Insisting on using digital from the devices is jst a rod for your own back with minimal or no sonic advantage.

Gadget

The background to this is that I have an old-school refrigerator guitar rack.

A combination of moderate hearing loss at 8K and finding the AF3 to be so good, I don't see myself going back to any kind of live / amplified sound.

Therefore I want to incorporate some of my unique rack pieces into my ITB setup, but also to be able to address each bit of outboard separately - for both guitar and general recording - rather than just run the whole rack in a loop of the AF3 for guitar only, which I tried for a while.

I don't have any particular concerns about the analog out quality on any of those pieces I'm trying to connect digitally. The problem is that I am limited on analog i/o (10 pairs) to my interface and still have a shed load of non-digital equipped outboard to add (2290, 1210, TERC, SPX90 II, etc.) so I'm trying to use digital i/o for those others that have it.

The 48K limit is a bit annoying, but not a deal-breaker for me as an amateur.

Current connectivity goes like this:

Axe FX III MkII Turbo coax SPDIF i/o <--> TC SK48 coax SPDIF i/o

Orville coax SPDIF i/o <--> M-Audio CO-2 coax SPDIF i/o --> M-Audio CO-2 optical toslink i/o <--> TC SK48 optical Toslink 1/2 i/o

PCM81 coax SPDIF i/o <--> M-Audio CO-2 coax SPDIF i/o --> M-Audio CO-2 optical toslink i/o <--> TC SK48 optical Toslink 3/4 i/o

Two Notes Torpedo Studio hasn't been added to this new setup yet, but it has AES too, so that is the aim.

So I'm not using any AES3 at the moment, converted or otherwise.

I am not using the AF3 as an interface, only the TC SK48, from which I am also running monitoring. The SK48 is ~15 years old now I think and I do have doubts as to its reliability.

I have tried a variety of clock setups. The most stable seems to be to set the TC SK48 to 'Internal' and then clock everything else to it. When the SK48 is on and has the AF3 and either the Orville or PCM81 running, it has a stable lock. However, if I turn the Orville and PCM81 on at the same time, it all goes to pot.

Despite the lock, I do get a half second dropout every 30 seconds or so, so something's not quite right somewhere. It could be my interface, it could be cables, it could be my PC Haswell CPU, it could be any one of the processors, it could be demons...

Best I can see so far for not massive cash is a secondhand Lynx AES16e PCIe card, but I'm not sure how well it would integrate with my other hardware.

Sorry for the length, but you asked for detail

octatonic

That is exactly the level of detail I needed.

OK, just to confirm that you have a BIDIRECTIONAL connection between all the digital devices?
So two S/PDIF cables between the Axe FX and the TC?
and so on...
This is important to know.

If you are using the TC as the clock master then everything else has to slave to it.
They should not be set to internal.
Have you set the clock to s/pdif on all of the devices, esp the Orville and PCM81?

The CO2's work to a point but I think the issue is going to at least in part down to using those.
The more digital devices you have connected the more important wordclock will be.
Running multiple s/pdif connections (with embedded clock) and then converting them from coax to/from optical I am not surprised that eventually it falls over.

The Lynx AES16 card is fine, if a little old now.
But I wouldn't suggest using it in addition to the TC.
If you want to replace it entirely then fine, but running aggregate devices is usually a recipe for disaster.
Does it do everything else you need?

There isn't going to be a cheap way of doing this that doesn't have some element of compromise, I am afraid.

There are very few audio interfaces with a large number of AES/EBU connections.
The Avid MTRX II does it with an option card, RME used to have one card but it is discontinued and there is the Lynx.

In your position I'd get an 8 channel converter, connect it over ADAT (using BNC wordclock for sync) and use a 1/4 patch bay to switch between 'guitar' and 'studio' modes by patching a few cables, rather than having to unplug everything.

Gadget

octatonic said:

That is exactly the level of detail I needed.

OK, just to confirm that you have a BIDIRECTIONAL connection between all the digital devices?
So two S/PDIF cables between the Axe FX and the TC?
and so on...
This is important to know.

If you are using the TC as the clock master then everything else has to slave to it.
They should not be set to internal.
Have you set the clock to s/pdif on all of the devices, esp the Orville and PCM81?

The CO2's work to a point but I think the issue is going to at least in part down to using those.
The more digital devices you have connected the more important wordclock will be.
Running multiple s/pdif connections (with embedded clock) and then converting them from coax to/from optical I am not surprised that eventually it falls over.

The Lynx AES16 card is fine, if a little old now.
But I wouldn't suggest using it in addition to the TC.
If you want to replace it entirely then fine, but running aggregate devices is usually a recipe for disaster.
Does it do everything else you need?

There isn't going to be a cheap way of doing this that doesn't have some element of compromise, I am afraid.

There are very few audio interfaces with a large number of AES/EBU connections.
The Avid MTRX II does it with an option card, RME used to have one card but it is discontinued and there is the Lynx.

In your position I'd get an 8 channel converter, connect it over ADAT (using BNC wordclock for sync) and use a 1/4 patch bay to switch between 'guitar' and 'studio' modes by patching a few cables, rather than having to unplug everything.

Yes, every connection is bi-directional / two cables.

SK48 is clock master. This makes sense if it'll work reliably, as it is the 'always on' device, unlike the outboard which I only tend to switch-on when needed.

Clock is set to external SPDIF on AF3, PCM81 and Orville.

Occasionally the SK48 decides to randomly set itself to 192KHz, obviously screwing-up all syncs, and one of the reasons I wonder whether it's dying (?)...

I agree that the CO-2s might be adding complications / causing problems, which is the main motivator behind switching everything to AES3, in the hope that direct cable runs will be more uniform and reliable.

The original AES16 is quite old, but the 'e' version has had a new driver as recently as this September  - https://www.lynxstudio.com/downloads/aes16e/windows-driver-v2-build-26/

It only has AES3 i/o, so could not be my only interface solution.

I think RME do an add-on AES-equipped unit to plug into one of their interfaces, but it's def too spendy. There doesn't seem to be any middle ground for AES: you either have a single AES i/o on a consumer/enthusiast interface, or multiple i/o on a pro unit at mega bucks.

I have just been playing the AF3 into the SK48 with first the Orville and then the PCM81 in an external insert with zero problems, but as soon as I turn both the Orville and PCM81 on at the same time, the clocking goes to pot.

Heartfeltdawn

OK, this is a fun one to look at. Octatonic lays out the issues very clearly. 48Khz running as dictated by the AFX3. 

RME do have the HDSPe AES which would handle four inputs at once. £855 from Scan, add in the DSub cable at around £70...

https://www.rme-audio.de/hdspe-aes.html

£855 from Scan. A suitable Dsub cable with 4 in and 4 out XLR connections for your external units is around £70 to £75.

https://www.rme-audio.de/aes-ebu-cables.html

How a DA/AD converter fits into this system, I am totally unsure. So I am unhelpful. 

But consider the RME AIO Pro card. You have a digital breakout cable offering 1x AES i/o and 1x SPDIF i/o. That would take care of two of the units. I think you can run multiple cards if your PC can handle it, giving you 2x AES and 2x SPDIF inputs. 

You'd also have the analog breakout cable options as well and you could chuck in the Arc control system. 

Gadget

Heartfeltdawn said:

OK, this is a fun one to look at. Octatonic lays out the issues very clearly. 48Khz running as dictated by the AFX3. 

RME do have the HDSPe AES which would handle four inputs at once. £855 from Scan, add in the DSub cable at around £70...

https://www.rme-audio.de/hdspe-aes.html

£855 from Scan. A suitable Dsub cable with 4 in and 4 out XLR connections for your external units is around £70 to £75.

https://www.rme-audio.de/aes-ebu-cables.html

How a DA/AD converter fits into this system, I am totally unsure. So I am unhelpful. 

But consider the RME AIO Pro card. You have a digital breakout cable offering 1x AES i/o and 1x SPDIF i/o. That would take care of two of the units. I think you can run multiple cards if your PC can handle it, giving you 2x AES and 2x SPDIF inputs. 

You'd also have the analog breakout cable options as well and you could chuck in the Arc control system. 

I have been looking at the RME cards and interfaces. I'm trying to get my head around what kind of system I really need now, and particularly whether or not I still need a conventional audio interface. Maybe just a card or two and breakout cables to the processors would do it?...

I'm not mic'ing amps anymore and rarely record a vocal so I don't need lots of preamps. However, I do still need monitor control and a headphone connector, etc. so not quite sure how I would square that (?) TotalMix would be a possibility, but I can see all this getting very cmplicated and expensive for not a lot of gain over where I am now.

Having said that, I'm getting more and more convinced that my long-serving SK48 needs retiring...