• From: Wien
  • Registered: 2022-05-04
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Topic: Room EQ - Output Delay >42,5 ms

Hello,

TotalMix FX allows a maximum output delay of 42.5 ms per channel in the Room EQ section. I would like to understand whether this limit is imposed by a hardware constraint (e.g., DSP buffer size or internal memory allocation), or if it could theoretically be increased in firmware.

My use case is a Dolby Atmos monitoring setup with active main monitors that introduce significant internal DSP latency. To maintain time alignment across all channels, I would need approximately 90 ms of delay on some outputs, which exceeds the current limit.

If increasing the delay within TotalMix FX is not possible, is there an alternative method using RME hardware to achieve additional output delay?

Thank you.

2 Reply by waedi (edited by waedi 2026-02-19 19:40:50)

  • waedi
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Re: Room EQ - Output Delay >42,5 ms

Wait, you have active loudspeaker monitors that have audio latency ?
Are they self made ?
What product is that ?

The Echo FX has 2 sec delay time max.
You can add a delay of let's say 80ms to every output needed and use the RoomEQ additionally on top of that to reach your optimization.

M1-Tahoe, Madiface Pro, Digiface USB, Babyface silver and blue

3 Reply by leomorello (edited by leomorello 2026-02-19 20:41:44)

  • From: Wien
  • Registered: 2022-05-04
  • Posts: 5

Re: Room EQ - Output Delay >42,5 ms

Thank you for the reply. I have found at least four other users on the forum who also require more than 42.5 ms of output delay (apologies for opening another thread on this topic). I will summarize the relevant posts below:

https://forum.rme-audio.de/viewtopic.php?id=38899

SeriousMastering wrote:

This is most likely a stretch (pun intended).
It applies to both software and hardware firmware.

I'm using the UFXIII as remote controller connected to Kii remote that allows for true phase correction for the connected speakers. Downside is that it introduces a delay of 90ms. Room Correction EQ goes up to 42.5 ms. Would it be possible to have it increased to 100ms?

bsfreq wrote:

+1

This would be very useful.
I asked the same for different reasons here:

Hopefully there will be enough demand for RME to implement this. I would think this is just a matter of reallocating the resources (RAM), as the TMFX echo is already able to handle longer delay times. Of course any changes done to TMFX will need to be mirrored to all versions, interface firmwares and remotes etc. so there will be some more work involved.

However, it would be much more user friendly to be able to dial in longer delay times directly on the outputs, instead of using the echo + loopback workaround to achieve the same. Also, echo is not as precise.

https://forum.rme-audio.de/viewtopic.ph … 16#p213416

aroom wrote:

@MC could it be possible somehow to go beyond the 42ms of delay?

I am aware of the Echo workaround:

MC wrote:

If you don't need the Echo for anything else then this is indeed possible with a funny workaround. You just have to use the Echo as only audio path (channel fader down with Send up, Return channel no routing active but FX return up). Echo effect used is Stereo Echo, Width 100, Feedback 0, HC Off, Vol 0 dB.

Now the stereo signal gets delayed by whatever you set as delay time and shows up at the output where you raised the FX Return fader.

However, this approach does not solve my use case, as Echo only allows a single delay value, while I require independent delay values for different speaker groups (surround layer, height layer, and subwoofers).

Like @SeriousMastering, my setup also uses Kii Three monitors, which use internal DSP to implement a cardioid radiation pattern via multiple drivers, and likely also linear-phase FIR crossover filters.
This is not unique to Kii. Many DSP-controlled loudspeakers exhibit similar latency, including Dutch & Dutch, Genelec SAM, Neumann DSP-series...

As @SeriousMastering suggested, a delay of 100 ms would be enough for the Kii Three. I don't know if other use cases would benefit from more.

  • From: Wien
  • Registered: 2022-05-04
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Re: Room EQ - Output Delay >42,5 ms

waedi wrote:

Not a good idea of mixing different loudspeakers with different latencies in one multi speaker setup.

This is common practice in immersive setups.

Any multi-speaker setup requires independent delay adjustment per channel to compensate for difference in acoustic path length. This applies regardless of whether the loudspeakers themselves have identical internal latency.
It could be necessary for several reasons e.g., in the case of an orthogonal speaker layout (not circular), center channel placement, subwoofer alignment, several DAC stages, ...

In Dolby Atmos setups specifically, the height layer is never equidistant from the listening position compared to the base layer (as per specification), so separate delay values are required to achieve correct time alignment at the listening position.

I think many use cases would benefit from a larger maximum output delay that can be set on a per channel basis.

  • Kubrak
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Re: Room EQ - Output Delay >42,5 ms

leomorello wrote:
aroom wrote:

@MC could it be possible somehow to go beyond the 42ms of delay?

I am aware of the Echo workaround:

MC wrote:

If you don't need the Echo for anything else then this is indeed possible with a funny workaround. You just have to use the Echo as only audio path (channel fader down with Send up, Return channel no routing active but FX return up). Echo effect used is Stereo Echo, Width 100, Feedback 0, HC Off, Vol 0 dB.

Now the stereo signal gets delayed by whatever you set as delay time and shows up at the output where you raised the FX Return fader.

However, this approach does not solve my use case, as Echo only allows a single delay value, while I require independent delay values for different speaker groups (surround layer, height layer, and subwoofers).

And why cannot you use Echo workaround? You may set Echo to, say 42.5 ms for those channels that need more than 42.5 ms and add additional delay in RoomEQ to make it up to 85 ms.

FF UCX II, Digiface USB, Babyface Pro FS
  • waedi
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Re: Room EQ - Output Delay >42,5 ms

@Kubrak you missed he says he has differences in latencies on his speaker set, bigger than the 42 ms, this brings him out of the limits.

M1-Tahoe, Madiface Pro, Digiface USB, Babyface silver and blue
  • Kubrak
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Re: Room EQ - Output Delay >42,5 ms

And Echo and RoomEQ delay do not add up? If they do add up, OP may set Echo 42 ms and RoomEQ 20 ms for channel A (making it 62 ms), 25 ms for channel B (making it 67 ms) and so on up to 85 ms in total.

FF UCX II, Digiface USB, Babyface Pro FS
  • waedi
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Re: Room EQ - Output Delay >42,5 ms

Yes but the difference never exceed the 42ms given as max delay in the room eq delay, thats his culprit.

M1-Tahoe, Madiface Pro, Digiface USB, Babyface silver and blue

9 Reply by MC

  • MC
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Re: Room EQ - Output Delay >42,5 ms

As the Echo workaround can be used only on one source I don't see how this helps in a surrond setup where you have multiple source channels to deal with.

Regards
Matthias Carstens
RME

MC's Website

  • From: Wien
  • Registered: 2022-05-04
  • Posts: 5

Re: Room EQ - Output Delay >42,5 ms

MC wrote:

As the Echo workaround can be used only on one source I don't see how this helps in a surrond setup where you have multiple source channels to deal with.

Thanks MC for weighing in. Exactly - echo is only stereo/usable on a single source, whereas in a multichannel monitoring setup we need to be able to set the delay independently for each output channel.

Since there seems to be quite a lot of development happening around TotalMix FX at the moment, with 2.0 now released and 2.1 in public beta, I wanted to follow up and ask whether there has been any development regarding eventually increasing the maximum delay available in Room EQ beyond the current 42.5 ms.

As mentioned above, something around 100 ms would already cover our use case.