Audio Interface from USB to AES XLR (per channel)

[MonitorsNZ]

Afternoon All

I've been working away at building a pair of Active Studio monitors.
After about 2 1/2 years of waiting for DSP's and delays on Class D amplifiers, they're making noise.

I'm currently running from an analogue signal from the PC to analogue XLR inputs on each monitor.
But the DSP's in each monitor can take digital AES inputs (via XLR).
I thought there would be a simple way to get from USB on a PC to separate L&R AES XLR connections.
This is my second weekend googling like mad and bothering my local music store without success.
If it had an input for a mic, so I can sort the frequency response with the digital x-overs, this would be ideal.

I'm hoping there's something under $500 that will achieve this.
(but I might be dreaming)....

Cheers...

Ben

 

[Blumlein 88]

This combined with a regular USB to SPDIF converter should work. You can use a BNC to RCA adapter on the input to this.

https://www.bhphotovideo.com/c/product/748792-REG/Sescom_SES_AES_EBU_2_75_Ohm_BNC_Female.html

Here is a review of two such converters. I have the one from Douk audio. Works fine, but I'm not using the Sescom converter.

PHIREE U2S 2019 & Douk Audio U2 Review and Measurements (Digital USB to S/PDIF Interfaces)

PHIREE U2S 2019 & Douk Audio U2 Review and Measurements (Digital USB to S/PDIF Interfaces) Update March 2022: Added comparison with the Douk Audio U2. Here is a quick review of the PHIREE U2S 2019 digital interface. This is basically some USB to S/PDIF converter that allows you to get USB...

www.audiosciencereview.com

However, I suppose this isn't separate L and R. I suppose you could two the above twice and mono it to left and right channels. Kind of inelegant.

 

[sam_adams]

There are several USB-to-AES/EBU converters mentioned in this ASR discussion. You can find more through a simple Google search.

 

[MonitorsNZ]

All of the converters mentioned above have a single AES XLR out. The challenge I have is that each monitor has a dsp with AES XLR in. This is due to the Accuton DSP192-4's only having 4 channels and the monitors being 3-way (so 1 dsp each). The AES XLR on a single channel seems uncommon.

 

[DWPress]

But the DSP's in each monitor can take digital AES inputs (via XLR)

What is the DSP module you used when you built your speakers?
edit: most of them have a way of talking to each other.

 

[MonitorsNZ]

One of these for each monitor.

https://www.boomaudio.de/media/pdf/ce/14/a7/Accuton_DSP192-4-111_quickstart.pdf

 

[MCH]

I think AES, like spdif, always carries two channels. But if you need two aes carrying each one channel, you could get a USB to 4 or more channels spdif or AES and just duplicate or route the channels you need to two different outputs, or mute the channel you don't need. (i.e. R duplicated to output 1 L duplicated to output 2...)
For instance using this:

U-DIO8

The miniDSP U-DIO8 is a pocket size USB Asynchronous interface with support for up to 8 channels of audio recording and 8 channels of playback. Inputs and outputs are digital (AES/EBU or SPDIF) and provided on a standard TASCAM pinout DB-25 to XLR (AES_EBU version) or DB25 to RCA (SPDIF version)

www.minidsp.com

 

[Kal Rubinson]

I think AES, like spdif, always carries two channels. But if you need two aes carrying each one channel, you could get a USB to 4 or more channels spdif or AES and just duplicate or route the channels you need to two different outputs, or mute the channel you don't need. (i.e. R duplicated to output 1 L duplicated to output 2...)
For instance using this:

U-DIO8

The miniDSP U-DIO8 is a pocket size USB Asynchronous interface with support for up to 8 channels of audio recording and 8 channels of playback. Inputs and outputs are digital (AES/EBU or SPDIF) and provided on a standard TASCAM pinout DB-25 to XLR (AES_EBU version) or DB25 to RCA (SPDIF version)

www.minidsp.com

The U-DIO8 has the standard grouping of channels 1-2, 3-4, 5-6, 7-8 on four cables (for input and for output).

 

[MCH]

The U-DIO8 has the standard grouping of channels 1-2, 3-4, 5-6, 7-8 on four cables (for input and for output).

Yes, but maybe he can route the audio in software so that one audio channel goes to udio channels 1-2 and the other to udio channels 3-4.
Camilladsp for instance can do it. (But to be honest I am not sure this is what he needs)

 

[jrosser]

Usually a monitor with AES input would also have an AES loop-through output to let you connect the same AES signal to the other monitor. You would then use some switch or setting on each monitor to select if it uses either the left or right channel data.

As your board does not have an AES loop out, you could connect the same AES signal to both monitors and then using the "input-mux" setting on the programming tool to select channel 1 for the first monitor and channel 2 for the second.

To get the same AES signal to each monitor a quick hack would be to use a Y cable, which will probably work with relatively short cables, but obviously a more proper solution is some sort of AES splitter with impedance matching.

I also tried adjusting the channel mapping with my RME audio interface and it's TotalMix software - it didn't seem possible to duplicate an input to two outputs with reversed L-R, I think that fixing this in your DSP boards to work with a single AES signal is the most elegant and would not require any special setup on your PC.

 

[pseudoid]

I'm currently running from an analogue signal from the PC to analogue XLR inputs on each monitor.

Q: How do you go from PC' analogue (single-ended? RCA outs?) to XLR?
FYI: AES67 - though a different VoIP standard - can do both PC's USB-C (2x2 bidirectional audio channels) as well as XLRs (IN/OUT): Unfortunately, you'd have to bring your own network to attach these clever Dante dongles (<$200/each) to your PC.

 

[DWPress]

One of these for each monitor.
https://www.boomaudio.de/media/pdf/ce/14/a7/Accuton_DSP192-4-111_quickstart.pdf

I briefly looked through the manual, have you read it? Seems pretty comprehensive, must be a way to at least mute L or R channel to work AES input just using a splitter at the very worst.

Alternately, you could get a USB DAC with XLR analog output to the analog input of the DSP boards in your speakers so you're at least feeding the DSP/amp the expected 4V via the balanced connection.

 

[DWPress]

Once you connect to your DSP modules and install Netcontrol2 you can route your signal within the software or just simply mute the L or R channel.



Digging deeper, looks like you need another pc board perhaps to allow the modules to talk to each other:



Are you using Pascal amps with these then?

 

[MonitorsNZ]

Q: How do you go from PC' analogue (single-ended? RCA outs?) to XLR?
FYI: AES67 - though a different VoIP standard - can do both PC's USB-C (2x2 bidirectional audio channels) as well as XLRs (IN/OUT): Unfortunately, you'd have to bring your own network to attach these clever Dante dongles (<$200/each) to your PC.

I found a cable from 3.5mm trs to twin XLR, which seems OK, but is running through the soundcard on the computer.

 

[DWPress]

Have you used the software yet? The solution is already there as I pointed out above.

 

[MonitorsNZ]

Once you connect to your DSP modules and install Netcontrol2 you can route your signal within the software or just simply mute the L or R channel.

View attachment 365004

Digging deeper, looks like you need another pc board perhaps to allow the modules to talk to each other:

View attachment 365006

Are you using Pascal amps with these then?

I went with Icepower 300 AS1 and a 300A1 on each side.

 

[DWPress]

Are you still using the Accuton DSP modules?

 

[pseudoid]

I found a cable from 3.5mm trs to twin XLR, which seems OK, but is running through the soundcard on the computer.

3.5mm TRS carries the high sides of the Left and Right channel (aka single-ended positive/each) and a mutual ground wire; where as the XLRs are a balanced pair requiring a dedicated positive AND a negative wire along with a third wire that is a ground potential.

 

[AnalogSteph]

Adapter cables like that typically tie 1 and 3 together at the XLR end. It works, if with the requisite ground loop. There are some more clever ways of wiring these but I wouldn't count on that being the case. I suppose one could just DIY a short pair of XLR extensions without the shield connected if need be...