Active Room Treatment (ART) by Dirac

[TimoJ]

If you’re looking for nice value for powering those Ultimax’s. I’ve had incredible luck with Crown XLS1002’s bridged. 1100W at 4ohm bridged. You can find them for $300 used. I actually found a refurb direct from Harmon for around that price.

I was actually thinking Crowns but XLS1502 bridged.

 

[jtatknox]

I have a 2.1 system with mains that go to 60 Hz or so. Hypothetically, how would you build out the system from here to 2.4 for 2 channel audio with Dirac ART in mind? I'm thinking a lot about adding 2x Rythmik FM8 since they go 18 Hz to 250 Hz. Where would you place them relative to the mains?

 

[IamJF]

There is a great document named multisubs_0.pdf which brings some light to this topic. Here some pictures from it with the best woofer positions.

Depending on your mains position - but assuming your mains are also woofers you could start with setup Nr.12.

 

[jtatknox]

Thanks, I think this is a useful document that I have seen before. I am just wondering what the recommended configurations might be to get the most out of ART specifically. I'm thinking that the approach to speaker placement and performance might be slightly different than when considering just a passive room.

 

[Dj7675]

Thanks, I think this is a useful document that I have seen before. I am just wondering what the recommended configurations might be to get the most out of ART specifically. I'm thinking that the approach to speaker placement and performance might be slightly different than when considering just a passive room.

I think trying a few different configurations would be interesting..
-2 subs one midwall in front and one midwall in back
-4 subs in corners
-4 subs midwall
Corners and probably the most room friendly and 4 would make sense though.
You may not have any desire to do so, but going with a 5.1 system would also give your 3 more speakers in the room for ART support as well. Not everyone wants or needs such a system but the more support speakers is helpful. I have a lot of speakers in my theater room but can switch it to stereo and the many other speakers contribute for ART use. While Stormaudio is the only ones offering ART now that will change and would expect Denon/Marantz, Monoprice HTP1 and possibly others. In some ways a great theater setup can also be a great Stereo setup.

 

[loddie88]

Something that I'm still trying to wrap my head around about ART: does "support" from other speakers only come in the form of this "anti-sound" or do they fill in with normal bass as well? If it's the latter, considering ART currently goes up to 150hz, wouldn't that start being locatable or make panning weird if, say, my rear surrounds were trying to contribute upper bass to my center?

 

[Dj7675]

Something that I'm still trying to wrap my head around about ART: does "support" from other speakers only come in the form of this "anti-sound" or do they fill in with normal bass as well? If it's the latter, considering ART currently goes up to 150hz, wouldn't that start being locatable or make panning weird if, say, my rear surrounds were trying to contribute upper bass to my center?

Support speakers are used for cancellation. When listening in stereo all speakers can be used as support speakers (including subs). Non Left/Right speakers would be used for cancellation and subs would be used for both as normal subwoofer play as well as cancellation. It is possible you could hear the cancellation signal when played back through the support speakers. However, if that is the case there are l any helpful settings..
1-You support how high you want ART to support. If you don’t want to support up to 150hz you can change it to whatever you want.
2-You also have control of how loud you want the support signals to play.
3-You can remove any speaker from support. For example if you have a surround speaker very close to you and don’t want to use it as a support speaker, just remove it from support
I tried everything set to default on my first calibration when doing the beta and when listening to 2 channel I did not notice any of the cancellation signals (their level is quite low). However, I did lower the support level on my surrounds since they are much closer than the other speakers in the room. I think isn’t an issue but options are there to adjust things if needed.
Hope that helps a little.

 

[GXAlan]

System listed below. …
Preamp: Monoprice Monolith HTP-1

Within the limitations of your Alpha tester agreements…

It seems like you have had good success with ART and the HTP-1… Any speculation why there is such a delay to release? Even the Focal Astral 16 lacks ART.

 

[loddie88]

Support speakers are used for cancellation. When listening in stereo all speakers can be used as support speakers (including subs). Non Left/Right speakers would be used for cancellation and subs would be used for both as normal subwoofer play as well as cancellation. It is possible you could hear the cancellation signal when played back through the support speakers. However, if that is the case there are l any helpful settings..
1-You support how high you want ART to support. If you don’t want to support up to 150hz you can change it to whatever you want.
2-You also have control of how loud you want the support signals to play.
3-You can remove any speaker from support. For example if you have a surround speaker very close to you and don’t want to use it as a support speaker, just remove it from support
I tried everything set to default on my first calibration when doing the beta and when listening to 2 channel I did not notice any of the cancellation signals (their level is quite low). However, I did lower the support level on my surrounds since they are much closer than the other speakers in the room. I think isn’t an issue but options are there to adjust things if needed.
Hope that helps a little.

Thanks for the response. From browsing Storm owners threads on AVSforum, I've seen some mention of limiting the strength of support levels because sometimes ART is so successful at lowering bass decay that it ended up sounding odd or less impactful. Did you ever experience that?

 

[TimoJ]

Within the limitations of your Alpha tester agreements…

It seems like you have had good success with ART and the HTP-1… Any speculation why there is such a delay to release? Even the Focal Astral 16 lacks ART.

Nothing major, just things that need to be done properly before release or even beta release. The actual ART DSP code works fine, it's mostly just things around it that controls loading/presets/ui etc.

 

[Curvature]

Thanks, I think this is a useful document that I have seen before. I am just wondering what the recommended configurations might be to get the most out of ART specifically. I'm thinking that the approach to speaker placement and performance might be slightly different than when considering just a passive room.

I think trying a few different configurations would be interesting..
-2 subs one midwall in front and one midwall in back
-4 subs in corners
-4 subs midwall
Corners and probably the most room friendly and 4 would make sense though.
You may not have any desire to do so, but going with a 5.1 system would also give your 3 more speakers in the room for ART support as well. Not everyone wants or needs such a system but the more support speakers is helpful. I have a lot of speakers in my theater room but can switch it to stereo and the many other speakers contribute for ART use. While Stormaudio is the only ones offering ART now that will change and would expect Denon/Marantz, Monoprice HTP1 and possibly others. In some ways a great theater setup can also be a great Stereo setup.

That document was produced by Todd Welti of Harman. The advice in it is based on simulated and measured configurations that prioritize flatness and SPL.

All of the boundary-loaded configurations @Dj7675 mentioned are investigated in Welti's AES papers and explained by Toole in his book.

I can't think of any reason why ART would require different or specific sub placement.

 

[abdo123]

That document was produced by Todd Welti of Harman. The advice in it is based on simulated and measured configurations that prioritize flatness and SPL.

All of the boundary-loaded configurations @Dj7675 mentioned are investigated in Welti's AES papers and explained by Toole in his book.

I can't think of any reason why ART would require different or specific sub placement.

I wouldn’t say “require” but i’m almost certain that theoretically speaking placing the speakers in an uncorrelated way will almost certainly help “fill up the gaps”.

The paper was about SPL output and response flatness with very little processing involved.

 

[IamJF]

Thanks for the response. From browsing Storm owners threads on AVSforum, I've seen some mention of limiting the strength of support levels because sometimes ART is so successful at lowering bass decay that it ended up sounding odd or less impactful. Did you ever experience that?

I absolutely can imagine that's a point for some listeners! Most people are used to boomy rooms and reflex speakers. That's what they expect - boooommm. Especially in home cinema.
With my closed volume speakers and stongly dampened room some don't like the precise, tight result - they miss the booming. They belive that's how it should be, never experienced prezise bass. And ART will be even more dry as my room ... c

 

[jtatknox]

That document was produced by Todd Welti of Harman. The advice in it is based on simulated and measured configurations that prioritize flatness and SPL.

All of the boundary-loaded configurations @Dj7675 mentioned are investigated in Welti's AES papers and explained by Toole in his book.

I can't think of any reason why ART would require different or specific sub placement.

One reason might be because ART produces anti-signal that you might be able to hear under certain circumstances. Another reason might be that because all-pass filters are used, you might be able to localize certain speakers near 150 Hz. Another reason might be that anti-signal might be more effective when the support speakers are able to actively cancel certain room modes more easily. Maybe asymmetric could be beneficial. You might want to go with a midbass woofer instead of a traditional subwoofer for the benefit of better midbass cancelling. Lots of reasons one might speculate but no concrete data or experimentation done yet. It's just a thought exercise.

 

[Dj7675]

Thanks for the response. From browsing Storm owners threads on AVSforum, I've seen some mention of limiting the strength of support levels because sometimes ART is so successful at lowering bass decay that it ended up sounding odd or less impactful. Did you ever experience that?

I suppose it could be a personal preference thing, but no I have not experienced that. In fact the opposite. Because the bass sounds so good I have increased the bass in dirac. I believe it is +8dB under 100hz. So there is actually more bass and more impactful than it has ever been.

 

[TimoJ]

From browsing Storm owners threads on AVSforum, I've seen some mention of limiting the strength of support levels because sometimes ART is so successful at lowering bass decay that it ended up sounding odd or less impactful.

I experienced this when I adjusted subwoofers support to main L/R to max value (-24) from the default. Measurements still looked fine but almost all bass impact was gone (tested with stereo music). Changed back to default -18 and all was fine again. I'll have to test again and check how decay looks, I only checked frequency response and didn't save the measurement.

 

[loddie88]

I wonder if my current setup of having two big subs nearfield (one on each side of loveseat facing inward towards the seats) will lead to complications. I love the added tactile response but wonder if I'll end up feeling all the corrective output from the subs in a weird way.

 

[abdo123]

@Flak

Is there a reason why Dirac has been mostly under the radar about ART?

Like there is barely any marketing material on your website and you have to dig down under the shopping for licenses under the Storm AVRs to even read anything about it.

Like we're all hyped and recognize this technology as the paradigm shift that it is but we're getting bread crumbs in return.

 

[tjcinnamon]

Nothing major, just things that need to be done properly before release or even beta release. The actual ART DSP code works fine, it's mostly just things around it that controls loading/presets/ui etc.

Is it possible to adjust the timings post calibration? On the Denon, once bass control is engaged the timings can’t be modified. I need to make sure the timings are aligned on my fronts (by that I mean they same) and I want to avoid having to run 3 measurements of 14 speaker calibration until I get one perfect…

I’ll get an HTP-1 over the Denon if modifying the timing after the calibration is allowed.

Basically: I have a X6800 waiting for pickup at Best Buy but I’ll return it before taking it home because of the timing issue based on speaker constraints I have

 

[ban25]

Is it possible to adjust the timings post calibration? On the Denon, once bass control is engaged the timings can’t be modified. I need to make sure the timings are aligned on my fronts (by that I mean they same) and I want to avoid having to run 3 measurements of 14 speaker calibration until I get one perfect…

I’ll get an HTP-1 over the Denon if modifying the timing after the calibration is allowed.

I don't understand why you'd want to modify the delays post-calibration. Doing so essentially nullifies the point of the calibration, and it would likely cause ART to stop working as the support channels would no longer be phase-aligned.

Do you actually sit precisely in between--as in down to the micrometer--your front speakers? Maybe you have a vise you put your head in while watching TV? Because if not, the delays measured by Dirac will be more precise.