Active Room Treatment (ART) by Dirac

[abdo123]

There is a huge reason to play your LFE over multiple subwoofers. Why do we use more than one woofer? Simply to get the SPL we need at these low frequencies. I use closed 10-12" drivers - you need a few of them to get the needed level at 20Hz.
I hoped with ART the system will use all of the woofers to produce sound and at the same time to chancell it - this would be huge for DBAs, double the amount of speakers to be active, instant 6dB more SPL (which could save quite some money during design).

We started doing this because of the traditional way we used to do bass management.

With ART i would be more than happy to:

1) crossover at lower frequencies than 80Hz

2) use one beefy 15 Inch sub instead of 4 10 inch or 4 12 inch as it will be supported by my speakers (unless my room is really large and my modes are below 40Hz).

 

[TimoJ]

This doesn’t make sense. Are you sure?

Traditional bass management send bass managed signals to the “LFE” not to all subwoofers.

What is LFE in your opinion? Isn't LFE just one of Dolby/DTS channels? So I don't understand what you are talking about.

 

[juliangst]

Ich kann als Österreicher ja zum Glück relativ gut Deutsch ...auch wenn wir uns in der Wortwahl meist uneinig sind



WHY?
You could still do a DBA with the front as 1 woofer and the back as 2nd woofer and ART will use it correctly?


What's happening in case there is no sub?

I think DBAs and SBAs are mostly a german/austrian phenomenon.
I have never seen anyone outside the german speaking community implementing a bass array (before Trinnov waveforming made it more popular).

So only having LFE on one subwoofer is indeed problematic for most users that just use 2-4 subs placed in their room.

 

[MickeyBoy]

There is a huge reason to play your LFE over multiple subwoofers. Why do we use more than one woofer? Simply to get the SPL we need at these low frequencies. I use closed 10-12" drivers - you need a few of them to get the needed level at 20Hz.
I hoped with ART the system will use all of the woofers to produce sound and at the same time to chancell it - this would be huge for DBAs, double the amount of speakers to be active, instant 6dB more SPL (which could save quite some money during design).

I should be a newbie for asking this question: is there any reason to use LFE for music? For Blu-Ray and SACD in particular I have never used LFE. "E" is for effects, naturlich.

 

[alont]

Full LFE signal goes only to first subwoofer.

What about the rest of the subwoofers? What do they get? I have three subs and one is considerably more capable than the others so I'm wondering if the best approach would be to designate it as the first subwoofer.

 

[Shimrra Jamaane]

So this is all really confusing. So what is the advantage to having a multi sub setup if you're using ART? Like, is it preferable to have as many "large" speakers for every channel as possible rather than multiple subs? So say one subwoofer and 6 full range towers instead of only having towers for the L and R but having multiple subs?

 

[Kal Rubinson]

Full LFE signal goes only to first subwoofer.

Depends on your setup/hardware. In my base setup with everything running under JRiver, I clone the LFE to my other subs before DL-ART gets access to them.

 

[jtatknox]

Full LFE signal goes only to first subwoofer.

Point of clarification: are you saying that first sub gets LFE only and subs 2-4 get LFE + support signals? Or do subs 2-4 only play support signals? Would this even be a problem unless you were dependent on multiple subs for loudness?

 

[Shimrra Jamaane]

How has ART been out in the wild for a year but its still a mystery box?

 

[pogo]

Depends on your setup/hardware. In my base setup with everything running under JRiver, I clone the LFE to my other subs before DL-ART gets access to them.

That's exactly what I would do, i.e. set up the lower layer with powerful full range speakers. That way you get optimum distribution under ART and you can save the cost of the DLBC license. What is often forgotten is that ART is not 'SUBs' and that frequencies above the usual sub range should also be optimally co-optimised.

 

[TimoJ]

Point of clarification: are you saying that first sub gets LFE only and subs 2-4 get LFE + support signals? Or do subs 2-4 only play support signals? Would this even be a problem unless you were dependent on multiple subs for loudness?

First sub plays LFE + bass managed signals from other channels + ART cancellation signals for different channels.
Other subs play support for LFE channel + bass managed signals + ART cancellation signals for different channels.
(default settings, you can remove/add/change support etc.)

What LFE support signal actually contains is a bit of mystery but its output level appears to be lower that full LFE and (upper) bandwidth is not full LFE.
But this is different in every room and subwoofer system.

Possible problems are lower total LFE output and also LFE sounds (and pressure) localisation to sub1.

 

[TimoJ]

Depends on your setup/hardware. In my base setup with everything running under JRiver, I clone the LFE to my other subs before DL-ART gets access to them.

How is that done? Since ART does bass management and splitting/filtering bass and LFE to different subs how can you clone LFE to other subs before ART? There shouldn't be subs before ART.

 

[dlaloum]

Depends on your setup/hardware. In my base setup with everything running under JRiver, I clone the LFE to my other subs before DL-ART gets access to them.

So Jriver pre-mixes all the sub channels and then delivers multiple sub channels to Dirac?

 

[TimoJ]

ART also doesn't seem to EQ subwoofers like regular Dirac does, it uses other speakers' support to do that. I'll have experiment what happens when PEQ is used before running ART.
For example, my second sub has pretty bad drop around 23Hz and regular Dirac corrects it. But ART doesn't use EQ for it, it just uses other sub/speakers to fix it.

 

[TimoJ]

Here is LFE channel REW measurements with ART correction, 7.2.6 setup. First picture has all speakers and two subs active. Next one has only subwoofer1 active. And the last picture has subwoofer1 turned off and sub2 and all speakers active. Both subs have 100Hz 24dB/oct lowpass filtering active. LFE channel is supported by other speakers to 150Hz.

 

[abdo123]

What is LFE in your opinion? Isn't LFE just one of Dolby/DTS channels? So I don't understand what you are talking about.

LFE in the context of ART is one subwoofer + support signals from everything else.

Not all the subwoofers available.

So there should be a difference. Otherwise it’s not consistent.

 

[Ze Frog]

I'm so glad I've never gotten into the room treatment rabbit hole, must be pretty darn expensive. If I had the money to build my own property, then maybe. Would be awesome to literally design the whole room shape and everything then incorporate all this stuff. In my standard UK entry level property, not so much.

Still, fascinating to see the effort and engineering put into all of this and many enthusiast's put into this kind of thing. Would love to experience a well treated room one day, never encountered such an environment so far.

 

[markus]

How has ART been out in the wild for a year but its still a mystery box?

Lack of broad availability, lack of proper documentation.

 

[Shimrra Jamaane]

I am now suddenly far less excited for ART regardless of how fair that is of me. Maybe DLBC multi sub is good enough for me for the next few years.

 

[abdo123]

Lack of broad availability, lack of proper documentation.

Dirac really dropped the ball on this to be honest.