AXR4 Digital limit

Could someone explain the reason for the limit on the digital io on the Axr4.
It has 16 adat and 8 aes/ebu channels, perfect for what I needed but if your using aes/ebu you loose 8 of the adat channels (so the manual would indicate)

Hello Powerbread,

The AXR4 has 2 digital I/Os.

The first digital I/O (Optical A) is only available as an optical connection.

The second digital I/O is available as an optical connection (Optical B) and alternatively as an AES/EBU connection.

So, in total the AXR4 provides 16 channels of digital I/O at 44.1/48 kHz.

Best regards,

Stefan Schreiber

Hi Stefan , thanks for the reply.
I have read the manual through and I think it is as great unit.

As a perspective buyer I would love to have seen 16 adat and 8 aes/ebu , 24 digital io total and 2 extra monitor outputs.
Just my 2c if it’s worth anything.

8 channels is the bandwidth limit of a single TOSLINK - not a limit of the interface.

I don’t think they’re making a point about the technical limitations of Toslink. Just stating they’d have liked 16 adat (I assume ins and outs) and 8 aes/ebu on the same unit. Similar to RME UFX+.


I can’t understand why (we are in 2019) the AXR4 that is a high end interface (can work at 384 KHz) is still using outdated ADAT ports for its digital I/O. It’s meaningless because at 192 KHz an ADAT i/o gives only two channels and ADAT cannot be used at 384 KHz

ADAT is limited because it is using old hardware components that cannot be used at a higher frequency. This mean that to get 8 channels, it needs to stay at 48 KHz. At 96 KHz it does support only 4 channels, at 192 KHz 2 channels, and eventually 1 channel at 384 KHz :laughing:

It would have been more comfortable to use a modern bus like AES50. Or eventually a switchable protocol like AVB (iso level 2 protocol) or DANTE / AES 67 (iso level 3 protocol).

MADI is still used by a few manufacturers and clients because of its low license cost and simplicity but is outdated. I think that for an interface like the AXR4, a modern ethernet based point to point protocol like AES 50 (iso level 1) would be ok and enough. It is low cost, is using standard Cat 5 network cables (100 meters max length), and can support 24 bidirectional channels (24 inputs and 24 outputs) at 96 KHz in a 100 Mbps implementation. More it is fully deterministic and low latency.

Hopefully will see soon a Steinberg / Yamaha interface with such a modern bus like AES50 that can be extended digitally with at least 16 inputs/outputs channels at 96 KHz. Would be even better if it would be compatible with existing AES50 products (KlarkTeknik, Midas, Behringer…) at least at 48 KHz and 96 KHz.

I’m sure the adat ports are there as a great connection option with new and older equipment.
The ARX4 has a great feature set, I think the 8 AES channels are awesome as most other interfaces don’t include this.
As mentioned earlier I’m just disappointed we can’t use all the digital connections (16 adat and 8 aes) at the same time.


Yes sure but ADAT is only useful at 44.1 or 48 KHz.

At 96 Khz or 192 KHz it’s not so useful, at least for multitracking, because of a very reduced channel count (4 or 2 channels only).

It is quite strange to see such a modern interface with modern Thunderbird computer connectivity that is using almost legacy digital I/O ports like ADAT.

Even at 96 KHz, the digital I/O connectivity is low, too low i feel for this price. So you need to buy two AXR4 units for multitracking at 96 KHz if you want a decent track count. The price of such a setup then become exaggerate.

The problem when cascading two units is that you need to use one ADAT port on each interface for low latency monitoring cascading. If not you loose low latency direct monitoring on the second interface… See the manual page 55

Monitoring when AXR4Ts are
connected in a stack

This is something that should have been done through a dedicated port, like this can be seen on Nuage interfaces that have dedicated ports fort that :

This problem do exist since the MR816 and UR824 interfaces and is still not addressed…

As opposite, a modern digital I/O port like AES50 would have given a good digital connectivity (24 Inputs and 24 outputs) at 96 KHz.
The AXR4, like its predecessors MR816CSX and UR824 has a great advantage, it is offering DSP effects for low latency monitoring, with full integration inside Nuendo / Cubase. No other interface brand do have this integration.

This mean that if you want something easy to use for multitracking, you have no other choice than Yamaha / Steinberg interfaces because they are the only ones to give an easy to use (and not confusing like other DSP mixer applications i did see) DSP mixer control from Cubase / Nuendo.

This is where the lack of a modern digital connectivity giving more I/O extension capability at 96 KHz is damaging to the interest of this interface, regarding its quite high price.

Now lets watch at the 384 KHz usefulness : it is quite reduced.The AXR4 does not have any digital I/O available at 352.8 or 384 KHz ! At this frequency neither ADAT neither AES are working (watch the manual page 78).

So you end up with analog I/O only at this frequency and there is no more DSP FX available, so no more direct monitoring with DSP reverb and hardware compression. Perhaps this can be used for some high end classical or jazz recordings with 2 or 4 mics, without need for DSP because here you don’t need performers monitoring, but not more.

Anyway i feel that 192 and 384 KHz is most of the time overkill.

48 KHz and 96 KHz are the way to go for 99% of the recording work; so interfaces should be designed with that in mind : they should give a good digital i/o connectivity at this frequency. This is not really the case unfortunately for the AXR4.

Hopefully we’ll see something better in this regard from Yamaha in the futur, eventually limited at 96 KHz, that is the maximum frequency used for 99 % of recordings. No need for 192 KHz or 384 KHz that are mainly for a very small niche market restricted to peoples who likes to buy speaker cables costing 1 K$ per meter or more and that do have platinum (for 192 KHz) or diamond (for 384 KHz) ears :laughing:

In the end because everybody has different needs, i feel that it would be better to have a modular system, similar as the Nuage one, using a modern digital I/O bus and monitoring cascading, but limited to 96 KHz / 48 I/O channels at a reduced price level compatible with the music market.

An interface with only AES50 connectivity and external I/O interfaces modules would be better i think than a fully integrated interface.

Then the development team goal would be met :
From the AXR4 manual :

The AXR4 is our flagship audio interface model, developed from the perspective of audio
engineers for use in professional music production.
Nuage cascade.png

Without saying the interface has not a decent quality, I felt since long that ADAT needs to arrive in the 21st century.
There is an opposition in the I/O count and max Khz of modern interfaces featuring ADAT.
For compatibility and also for good price/value ADAT still seems fine today but just looking at I/Os I’d like to have something new.

Seems though that there is no such standard like ADAT yet in the consumer segment. LAN would be great, as on first look it seems to be easy to connect (cables are cheap and reliable too).
Fiber optics was my vision when I was younger. Having thin “wires” to connect many I/Os to computers and/or outbound gear seemed to be “the future”.
Now I am struggling to understand AVB,MADI,SPDI,TOSLINK,ADAT (I know I am mixing things)…