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Active Room Treatment (ART) by Dirac
- Thread starter Flak
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Talisman
Major Contributor
Personally, I solved the loudness problem with my Denon by using the three Dirac filters available on the receiver.
One setting is for music, one for low-volume music (with increased bass and treble), and one for movies (movies tend to have very intense bass tracks, and with the music setting, I found them to be overdone).
One setting is for music, one for low-volume music (with increased bass and treble), and one for movies (movies tend to have very intense bass tracks, and with the music setting, I found them to be overdone).
That certainly can work well. I still can’t comprehend that bass/treble are disabled with Dirac enabled. My order of preference to adjust audio…
1-Loudness compensation
2-Bass/Treble adjustments
3-Presets
Maybe Denon/Marantz will get this addressed at some point.
markus
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I think Denon/Marantz are applying loudness at the wrong point in the signal chain, and Dirac is limiting any processing downstream of its filters. So the real issue isn’t Dirac, people here should be thanking them and pushing Denon/Marantz to sort this out. They’ve been in the business long enough to know how to design a proper signal flow, so this shouldn’t really be happening.
Keith_W
Master Contributor
These are the same clowns who think that the speed of sound is 300m/s. They crippled their own AVR's with this incorrect value so the user has to calculate and apply the correction factor themselves.
markus
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To be fair, this has no practical consequences as long as the value remains constant, since all delay and distance values only need to be relative anyway.
There were literally thousands posts on forums about the effect of the "bug" that D&M refused to call a bug, but have fixed in X900H series release (not prior series though). MultiEQ-X fixed it automatically for older AVRs. However, it is definitely utterly stupid that D&M would try to pull this off as it is just a completely wrong assumption. So while it definitely did not "cripple" AVRs, it embarrassed D&M for sure.
The bug would not be audible by definition if the distance from MLP to all speakers was the same. However, if not the same, it is simple math that it would affect the timing over non equal distances. Some people could not hear the difference, some could, so it is really inconclusive as in normal setup the differences were minimal at best, and likely not audible. @peng is one of the speed of sound specialists around here.
The bug would not be audible by definition if the distance from MLP to all speakers was the same. However, if not the same, it is simple math that it would affect the timing over non equal distances. Some people could not hear the difference, some could, so it is really inconclusive as in normal setup the differences were minimal at best, and likely not audible. @peng is one of the speed of sound specialists around here.
Thanks, not a specialist at all, just thought there were no shortages of misconception on this and one being that Denon/Marantz/Audyssey actually measures time/delay so the distance in metric of imperial units are only for display. As such, the sound of speed/distance conversions wouldn't necessarily matter, say not always matter, but depends on the individual use case. I tried debating that with one of two die hard believer on AVSF (who claimed that "bug" caused obvious audible effects regardless, but I had to give up (not give in Lol), and I would not try to elaborate here to avoid derailing the thread.
So I would assume may be suffice to say, that imo Denon/Marantz should, as you said, have acknowledged that it was a bug, as it clearly was. Though I am pretty sure in probably most cases it would not make any difference, and in cases where the "bug" would make a difference, the difference would not likely be audible to untrained ears who are looking to hear the differences. Obvious, all those on AVSF who knew of that bug, would hear the differences even is in their use case there would have been no differences, not even theoretically speaking.
One example/argument I cited was: if one use the app to run Audyssey, made no tweaks, then the app/mic would measure time delay, NOT distance in inches/cm, calculate the filters accordingly, then upload the data to the AVR, the AVR will then calculate the distance using the inaccurate velocity of sound constant for display, so why would those people hear the night/day difference? In such a case (again just an example), Denon/Marantz would be right in saying it is not a bug, that it really is, just that D+M engineers know it is a bug that has no effects, except in some/many use cases. So again, D+M should have done a better job explaining, then appearing to be just denying.
Anyone disagreeing with my point I would just agree to disagree in order not to derail the thread.
I doubt they actually think that, it seemed to me at the time, some of them just didn't think it matters for the software to work as intended. As Oddball alluded to, there are many posts on that topic, one just have to revisit them to realize what were actually stated, claimed, debunked, debated, or just discussed.
ban25
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Agreed. Applying it closest to the source is preferable. I don't have much need for loudness curves, but if I apply one for music, I do it through Roon.
Hello,
i've been using DIRAC ART with a Storm audio ISP since Jan 2026. I came from an Anthem AVM90 with ARC Genesis.
DIRAC ART has both impressed me with the bass decay and clarity, and at the same time frustrated me with the weird and unpredictable bass impact performance with HT and multichannel concerts content.
In stereo, the bass decay, texture and transient clarity is very very good. However, this strength does not translate to HT and multichannel concert content. Some HT content have very good bass transients and impact, similar to stereo, yet other HT content the bass sounds smeared, sluggish and vague. This was absolutely confounding to me.
After a lot of digging and troubleshooting, measurements, i think i have finally figure out the explanation. The hint was the 'known issues' in the DIRAC ART release notes.
This has been mentioned many times in this thread, but so far i don't think anyone really understand what it means and how it impacts the performance of DIRAC ART with actual bass content.
First, let me share measurements of what this 5ms LFE delay means. It means that LFE channel content, played through the subs, is literally delayed 5ms, as stated. This is in contrast with the channels, where with bass management, the subs will also play redirected bass from channels.
The diagram show the acoustic timing reference step response of the LCR channels, and the LFE channel. I have labeled the peak of the subwoofer (playing redirected bass ) step response from LCR channel as '1', and the subwoofer (playing LFE content) step response peak from LFE channel as '2'. One can immediately see the ~ 5ms delay that is stated in the DIRAC release notes.
In the next diagram, it is the same acoustic timing reference measurement of the LCR and LFE. However, i have muted the LCR channel, leaving only the Subs active and playing the bass management redirected bass from LCR. These still peak at '1', and the LFE with the delay peaks at '2'.
What does this mean, and how does it explain why some HT content bass impact sounds clean and tight, while other HT bass sounds smeared and vague, less precise and less impact?
I think it has to do with the relative amount of bass information in the (LCR) channels, vs the LFE channel. This is what i mean, and i try to break it down to a few scenarios.
1) No significant bass in LCR channels, bass mainly mixed in LFE channel. In this scenario, DIRAC ART will perform marvelously, bringing all the clean decay, precise texture, transient impact that ART excels in. This is because there is not redirected bass from LCR, playing in the LFE, so there is only one bass transient peak, at '2' during playback.
2) Significant bass content in LCR channels, complimenting bass mixed in LFE channel. For eg, in 13 hrs First Wave scene, the gunshot impacts. There is significant bass transient peak from gunshots in LCR channel, in addition to LFE channel bass transient peak.
In this scenario, the 5ms LFE delay bug wreaks havoc in the bass playback, for both HT and multichannel concerts, especially gunshots and kick drums.
One common example is Roy Orbison's Blue Bayou from Black and White Night. The song starts with a very nice transient acoustic bass + kick drum impact, that is very noticeable smeared and less precise on ART.
Another common track is Green Day's Boulevard of Broken Dreams concert track, another bass kick drum monster test track. With DIRAC ART, the bass kick drum is a pale shadow of what it could be, what it should be.
The reason this happens, is the bass impulse peak content from LCR, being redirected and played by subs, is peaking at '1', and then at the same time, the same complimentary bass impulse peak from LFE channel, played by the same subs, is peaking at '2', a good 5ms later. The result is the transient impact peak is smeared across 5ms.
Another way to think about this, with multiple subs. What happens when you intentionally delay half the subs 5ms from the other half? There will likely also be associated cancellations between the first and 2nd peaks.
3) Significant bass content in LCR channels, little / no bass content in LFE. This is common for stereo 2.0 tracks, or multichannel 5.0 or 7.0 concert tracks, often classical concerts are mixed / mastered these way. With these content, ART again shines with bass reproduction. The subs (redirected bass) will peak at '1', there is no LFE channel bass to peak at '2' to cause smearing or cancellations.
I hope this post raises awareness and understanding of this issue and DIRAC can implement the fix very soon in the next release.
I truly believe ART brings the next level of bass performance in room, and already enjoy the incredible results with stereo content. I hope to enjoy similar with all my HT and concert content as well.
Thanks for reading.
Gavin
i've been using DIRAC ART with a Storm audio ISP since Jan 2026. I came from an Anthem AVM90 with ARC Genesis.
DIRAC ART has both impressed me with the bass decay and clarity, and at the same time frustrated me with the weird and unpredictable bass impact performance with HT and multichannel concerts content.
In stereo, the bass decay, texture and transient clarity is very very good. However, this strength does not translate to HT and multichannel concert content. Some HT content have very good bass transients and impact, similar to stereo, yet other HT content the bass sounds smeared, sluggish and vague. This was absolutely confounding to me.
After a lot of digging and troubleshooting, measurements, i think i have finally figure out the explanation. The hint was the 'known issues' in the DIRAC ART release notes.
This has been mentioned many times in this thread, but so far i don't think anyone really understand what it means and how it impacts the performance of DIRAC ART with actual bass content.
First, let me share measurements of what this 5ms LFE delay means. It means that LFE channel content, played through the subs, is literally delayed 5ms, as stated. This is in contrast with the channels, where with bass management, the subs will also play redirected bass from channels.
The diagram show the acoustic timing reference step response of the LCR channels, and the LFE channel. I have labeled the peak of the subwoofer (playing redirected bass ) step response from LCR channel as '1', and the subwoofer (playing LFE content) step response peak from LFE channel as '2'. One can immediately see the ~ 5ms delay that is stated in the DIRAC release notes.
In the next diagram, it is the same acoustic timing reference measurement of the LCR and LFE. However, i have muted the LCR channel, leaving only the Subs active and playing the bass management redirected bass from LCR. These still peak at '1', and the LFE with the delay peaks at '2'.
What does this mean, and how does it explain why some HT content bass impact sounds clean and tight, while other HT bass sounds smeared and vague, less precise and less impact?
I think it has to do with the relative amount of bass information in the (LCR) channels, vs the LFE channel. This is what i mean, and i try to break it down to a few scenarios.
1) No significant bass in LCR channels, bass mainly mixed in LFE channel. In this scenario, DIRAC ART will perform marvelously, bringing all the clean decay, precise texture, transient impact that ART excels in. This is because there is not redirected bass from LCR, playing in the LFE, so there is only one bass transient peak, at '2' during playback.
2) Significant bass content in LCR channels, complimenting bass mixed in LFE channel. For eg, in 13 hrs First Wave scene, the gunshot impacts. There is significant bass transient peak from gunshots in LCR channel, in addition to LFE channel bass transient peak.
In this scenario, the 5ms LFE delay bug wreaks havoc in the bass playback, for both HT and multichannel concerts, especially gunshots and kick drums.
One common example is Roy Orbison's Blue Bayou from Black and White Night. The song starts with a very nice transient acoustic bass + kick drum impact, that is very noticeable smeared and less precise on ART.
Another common track is Green Day's Boulevard of Broken Dreams concert track, another bass kick drum monster test track. With DIRAC ART, the bass kick drum is a pale shadow of what it could be, what it should be.
The reason this happens, is the bass impulse peak content from LCR, being redirected and played by subs, is peaking at '1', and then at the same time, the same complimentary bass impulse peak from LFE channel, played by the same subs, is peaking at '2', a good 5ms later. The result is the transient impact peak is smeared across 5ms.
Another way to think about this, with multiple subs. What happens when you intentionally delay half the subs 5ms from the other half? There will likely also be associated cancellations between the first and 2nd peaks.
3) Significant bass content in LCR channels, little / no bass content in LFE. This is common for stereo 2.0 tracks, or multichannel 5.0 or 7.0 concert tracks, often classical concerts are mixed / mastered these way. With these content, ART again shines with bass reproduction. The subs (redirected bass) will peak at '1', there is no LFE channel bass to peak at '2' to cause smearing or cancellations.
I hope this post raises awareness and understanding of this issue and DIRAC can implement the fix very soon in the next release.
I truly believe ART brings the next level of bass performance in room, and already enjoy the incredible results with stereo content. I hope to enjoy similar with all my HT and concert content as well.
Thanks for reading.
Gavin
KenMasters
Active Member
I'm hoping we see Dirac implement an LFE LPF bypass option soon. It's a quick and easy fix for what otherwise seems to be a complex problem.
Last edited:
I don't know what you can do with your Storm processor but I use Dirac Live via a VST plugin in the JRiver MC software player. This issue also occurs for Dirac Live Bass Control (DLBC). With JRiver MC to potentially help with this issue I think one could.
Delay all speaker channels except the LFE(.1) channel by 5 milliseconds before DLBC/ART processing.
...or...
Move the LFE(.1) channel into some or all of the speaker channels.
If either one of these options seems viable, could you implement either on your Storm processor?
Last edited:
RenPa
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agreed!
ernestcarl
Major Contributor
If this really is the case, below visualizes the summed result of two IRs (full-range main channel and a LP filtered +10dB LFE channel):
Seems "easy" to fix conceptually by just inserting a 4ms offset before summing the signals digitally.
KenMasters
Active Member
I'm not sure it is that easy. Firstly the LFE signal stands separate from the bass managed signal, then combined for final output - don't know how much control Dirac has over this process across devices (given what I've found with stereo and my Denon). Secondly, Dirac says "about 5ms", which makes me wonder if there is variation in the precise delay introduced across setups.
It just seems to me that if it were as easy as delaying the rest of the signals by 5ms, Dirac would have done it already.
Would they? That added delay might be considered inappropriate in a professional live tracking setup.
Also, I presume that more delay means more buffering, and there might be devices that can't handle that.
KenMasters
Active Member
What's an extra 5ms when ART already adds +-40ms?
5ms.
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