Master list of ASIO Direct monitor capable hardware?

Is there a list of interfaces that support ASIO direct monitoring - other than RME and Steinberg? Everyone states Cubase compatibility but no mention of direct monitoring.


This is an interesting subject.

I own a MOTU 828 mk3 so i can say it is ASIO direct monitoring capable.

To be able to support ASIO direct monitoring, a card needs a choice of this :

  1. a hardware analog mixer, controlled by the asio direct monitoring protocol (very rare, i’m not sure if it does exist)

  2. a hardware dsp mixer, controlled by the asio direct monitoring protocol.

In both case, the presence of a dedicated analog or dsp mixer alone is not enough. The analog or hardware dsp mixer needs to understand ASIO direct monitoring protocol, to be able to send record armed inputs directly to the monitor or cue outputs during record.

And it seems that there is mainly two levels of ASIO direct monitoring support :

The first implementation level is a basic switching support, that does only allows record armed inputs to be sent to monitoring outputs. This implementation level does not take into account the mix levels and pan positions of the DAW mixer.
The second implementation level sends the DAW mix fader levels and pan positions to the interface hardware dsp mixer, so that you don’t need to use the audio interface mixer software to set this up.

A third implementation level (i’m not sure that this is a part of the ASIO direct monitoring specification) would be to be able to automatically duplicate the record armed track effects and effects levels and settings to the DSP mixer.

Some cards manufacturers do propose a duplicate of their interface DSP effects as a VST plugins, so that you can get almost the same sound during recording in the performer headphone. But the process is manual, you need to put the same effect on the daw and dsp mixer and set it with the same settings. This is an approximation of this third implementation level.

I’m not sure but eventually high end solutions like Nuage could have that third implementation level with automatic management of the correspondence between the daw mixer and dsp mixer effects and effects settings.

To my knowledge, RME, Steinberg and MOTU interfaces do have the second implementation level, using a hardware dsp mixer in the interface, eventually completed by VST plugins to mimic the sound of the DSP mixer in the DAW mixer. Prism Sound as well on key models.

They do allow to add a reverb on the monitor outputs, using the interface dsp mixer, avoiding a dry monitoring of the armed inputs during record.

There are certainly other interfaces that do have this today, i would be interested to know witch one, and witch implementation level they have.

I think that for serious recording, the second implementation level is mandatory, to have an efficient recording setup.

Some performers (specially for guitar recording) are embarrassed when there is more than a few milliseconds of latency, so direct monitoring is then mandatory.

Some cards do allow as low as about 1.5 ms or even 1 ms of I/O latency. We could think that this could inhibit the necessity to have such an ASIO direct monitoring capability. But as soon as the DAW mixer has a few tracks and effects on them, i’m almost sure that this very low buffer setting needs to be rised a lot.
In the end, this ASIO direct monitoring capability is what make an audio interface really professional, compared to an interface that do not have it, or that do have a simpler direct monitoring method.

Some interesting background here about direct monitoring :

Another level of support is the number of monitoring buses that can be used for ASIO direct monitoring.

Some interfaces or software are limited to a single stereo bus.

If you watch at AVID, full direct monitoring support is only available on HDX systems, other systems, even the HD ones, are limited to a single monitoring bus.

In a pro studio setup, it is desirable to have more than one monitoring bus. It is not uncommon to use two or three separate cue buses for performers headphones, so they can get different mix levels for their comfort.

Other systems (seems to be the case for the MR816x or MR816csx), when more than one interface is used, cannot daisy chain the direct monitoring signal to the interface where the monitoring bus is located, seriously degrading the direct monitoring usefulness for tracking sessions with more inputs that the input count of the interface where the monitoring bus is located.

In practice, with Steinberg hardware, this is limiting the number of direct monitor inputs (at 96 KHz sampling frequency) to 12 inputs (MR816) or 16 inputs UR824. :frowning:

Or 16 inputs and 24 inputs at 48 KHz sampling frequency. (the difference does come from the ADAT ports than can only get 4 channels at 96 KHz :laughing: ).

It seems that there are very few manufacturers and interfaces with full low latency monitoring support, and most if not all of them are pro expensive interfaces or networked audio systems.

Those interface are often those that fall in the real pro category, with +4dBu inputs and outputs at -18 dBFS (at least + 22 dB of headroom).

If you watch at the market, all mid end interfaces, even RME ones for examples, are limited to 18 or 19 dB headroom (+4dBU at -14 dBFS). This mean that they cannot be seriously integrated in a professional studio setup, where other hardware is using -18dBFS most of the time.

So those two capabilities, full direct monitoring support and true +4dBu support are segmenting the market between consumer and pro level interfaces.

Last, there is at least one manufacturer that try to push to the market a large channel count Thunderbolt interface without DSP. This mean no interface direct monitoring capability. The monitoring is always done through the DAW.

If their low latency performance is ok in the order of the millisecond, i’m septic about the possibility to use them at such a low buffer setting, as soon as there is a few effects and a few channels in the DAW mixer, something quite common when tracking a band…

The conclusion is that the direct monitoring capability, when fully implemented, rise the price of the hardware, a lot… But when you need it, you need it.