Active Room Treatment (ART) by Dirac

[Oddball]

It's a good option to use, no breaks when switching content. The only difference between continuous and standard is that continuous engages all channels at all times, instead of jumping between 2ch and multichannel configurations.



You can see the waveform represented on the timeline below the videos, how the volume is attenuated when approaching 120Hz - it's what you'll hear as well.



Yes, just so.



Yes, when using bass management with Stereo modes. It seems though, when there is already a discreet LFE signal present as is the case in continuous mode, Dirac/Denon process it different, sending the redirect bass to the subs but not as LFE.

Search me as to why

That is ATV bug, nothing to do with D&M. CM should be disengaged as produces output that D&M is not able to process. They introduced CM for Sonos and soundbars, and I am not aware that we, the AVR folks, had any connection issues before. There is also a new ATV option for stereo - but as expected, I did not test that as not really that much interested in it.

 

[JRowland]

It's a good option to use, no breaks when switching content. The only difference between continuous and standard is that continuous engages all channels at all times, instead of jumping between 2ch and multichannel configurations.



You can see the waveform represented on the timeline below the videos, how the volume is attenuated when approaching 120Hz - it's what you'll hear as well.



Yes, just so.



Yes, when using bass management with Stereo modes. It seems though, when there is already a discreet LFE signal present as is the case in continuous mode, Dirac/Denon process it different, sending the redirect bass to the subs but not as LFE.

Search me as to why

I am also curious about something else and that specifically is will my system behave the same as yours since we know you have a 4ms timing difference shown on your impulse response plots and I do not. I don't believe this (the dotted line) timing has anything to do with the 5ms LFE delay, that's my guess and what I'm going off for now. So If I play the same 2.0 youtube clip and hear no dip with either Apple TV setting it could mean that your other timing error is causing your dip and it is a system specific problem is my thinking. Does that make sense to you?

 

[KenMasters]

That is ATV bug, nothing to do with D&M. CM should be disengaged as produces output that D&M is not able to process.

I'm sorry, I think you misunderstand. There is no bug, it does what it's supposed to and works well.

They introduced CM for Sonos and soundbars, and I am not aware that we, the AVR folks, had any connection issues before.

It's normal for devices to have to lock on to a new signal, there is a gap in audio when the change is made. Continous audio makes it so that the AVR sees full multichannel PCM at all times, but the content is still sent and presented as intended i.e. stereo in stereo.

 

[Oddball]

I'm sorry, I think you misunderstand. There is no bug, it does what it's supposed to and works well.



It's normal for devices to have to lock on to a new signal, there is a gap in audio when the change is made. Continous audio makes it so that the AVR sees full multichannel PCM at all times, but the content is still sent and presented as intended i.e. stereo in stereo.

Then you know better than me. I can't upmix the multi-channel with CA at all when signal is e.g not Atmos but 5.1.

Not sure about the gap - from recollection, it did not really help to shorten the lock-in time on my AVP. Every time you change the signal there is a slight delay, but not more than 2-3 sec in my experience. CA did not that make that any better - like no delay at all.

 

[KenMasters]

I am also curious about something else and that specifically is will my system behave the same as yours since we know you have a 4ms timing difference shown on your impulse response plots and I do not. I don't believe this (the dotted line) timing has anything to do with the 5ms LFE delay, that's my guess and what I'm going off for now.

Yes, given the new information I agree. What we're seeing is the intended behaviour. Though I still don't think the dotted line is necessarily meant to align with that of the speakers.

So If I play the same 2.0 youtube clip and hear no dip with either Apple TV setting it could mean that your other timing error is causing your dip and it is a system specific problem is my thinking. Does that make sense to you?

I don't think there is a timing error. My bass response is smooth and flat - it only happens in this particular instance and suspiciously at the 120Hz mark. Try it and see what happens with your system.

 

[KenMasters]

Then you know better than me. I can't upmix the multi-channel with CA at all when signal is e.g not Atmos but 5.1.

No, you can't, you can only get whatever the native signal is. If that doesn't work for you and you'd rather have the switching, do that then. Personally I don't upmix my content and even if I did, I would prefer the gapless experience.

Not sure about the gap - from recollection, it did not really help to shorten the lock-in time on my AVP. Every time you change the signal there is a slight delay, but not more than 2-3 sec in my experience. CA did not that make that any better - like no delay at all.

CA made no change to that behaviour? Well, on the Apple TV is makes shifting between content completely seamless for me.

 

[smygolf]

Oh, that is a bit strange. I assumed I am just stuck in the stone age .

@smygolf - are you sure you have ART active when attempting to adjust levels, etc? Seems like all around that should/is not possible on D&M?

As i mentioned before, receiver is on auto update and second to last version of Dirac.
And Yes i am sure Dirac is engaged.

I cant change distance, only lvl.
But there aint any use for it, it screews with ART, 1 dB is enough.

 

[JRowland]

Yes, given the new information I agree. What we're seeing is the intended behaviour. Though I still don't think the dotted line is necessarily meant to align with that of the speakers.



I don't think there is a timing error. My bass response is smooth and flat - it only happens in this particular instance and suspiciously at the 120Hz mark. Try it and see what happens with your system.

Thinking it though more the continuous audio toggle wouldn't make a difference with the dotted line timing anyway as all signals would be the same timing. I failed to think it all the way through before I posted, I'm still gonna try it tonight but you're thinking is correct to me that the 5ms LFE delay would be affected by toggling continuous audio..

 

[KenMasters]

Thinking it though more the continuous audio toggle wouldn't make a difference with the dotted line timing anyway as all signals would be the same timing. I failed to think it all the way through before I posted, I'm still gonna try it tonight but you're thinking is correct to me that the 5ms LFE delay would be affected by toggling continuous audio..

Further to the sub timing discussion, I ran a little experiment on a hunch. I have three subs, two are matching, the third is from a different manufacturer. You can see how different their impulses are and the difference in where Dirac has marked them:

Now see what happens when I remove the dissimilar one:

I don't think the dashed line not lining up with the speakers is an issue. I think it's a consequence of Dirac doing what it has to do to align the subs and speakers. I think ultimately where it lands in time is what Dirac finds to be the best fit.

If the first pic was not the correct timing, then delaying by 5ms would not have the detrimental effect on the output it seems to be having.

 

[RenPa]

the fargate guy on AVS (Ren something on here IIRC).

FargateOne = REnPa here!

 

[JRowland]

Further to the sub timing discussion, I ran a little experiment on a hunch. I have three subs, two are matching, the third is from a different manufacturer. You can see how different their impulses are and the difference in where Dirac has marked them:

View attachment 530467

Now see what happens when I remove the dissimilar one:

View attachment 530470

I don't think the dashed line not lining up with the speakers is an issue. I think it's a consequence of Dirac doing what it has to do to align the subs and speakers. I think ultimately where it lands in time is what Dirac finds to be the best fit.

If the first pic was not the correct timing, then shifting it up by 5ms would not have the detrimental effect on the output it seems to be having.

Nice! Seems to correlate like @mmares056 noticed with the strength of the impulse response. In my mind the consequence you mention though does not necessarily equate to "best result" so I'm not sure there is no issue at all, not sure there is either. Have you listened to both, specifically for percussion and plucking of things type sounds by chance?

 

[JRowland]

FargateOne = REnPa here!

If I could have shortened them both to one syllable I would have, I hate typing nothing personal

 

[KenMasters]

Nice! Seems to correlate like @mmares056In my mind the consequence you mention though does not necessarily equate to "best result" so I'm not sure there is no issue at all, not sure there is either.

Best result I would imagine would be to have three of the same subs, but that wouldn't have worked in the position I needed the sub to be in.

If you mean would it be better if the dashed line were delayed by the 5ms "early" it arrives at currently - well it looks like we have the answer to that

Have you listened to both, specifically for percussion and plucking of things type sounds by chance?

Absolutely, without a doubt, the third sub adds tremendously to the presentation. I purchased it/them (it is in fact two subs co-located) to fill a hole in the response the other two could not cover. Bass is smooth and tight, and distinctly superior to the two subs alone.

EDIT: The blue trace is the third sub:



And once ART has done its thing:

 

[JRowland]

This was my assumption as well, and I saw no evidence of an issue in any of my initial measurements. Then one day I listened to a sweep using a 2.0 YouTube test clip, my system would dip in output at 120Hz.

I just tried the clip again, the dip is gone. So I don't know why I was experiencing that issue before. Perhaps it was fixed in an update, perhaps an issue with my prior ART setup (I added a sub in the interim necessitating new measurements).

This is good news though. I guess the question is whether or not the positioning of the LFE channel relative to the other channels is the intended behaviour or not. I would imagine it is, but if others want to experiment with delaying their subs, I'd be interested in what affect it has on the response.

EDIT: Okay, interesting, I got to the bottom of the inconsistency. I use an Apple TV, Apple added a new audio option called "continuous play". With this active, the Apple TV plays all content in the Dolby MAT PCM format so that there are no audio breaks when switching content. When I switch continuous play off, the dip is back!

Working theory, in continuous play mode the AVR sees a multichannel input with active LFE channel, playing signals as assigned, so stereo sent to L & R only. With continuous play off, the AVR's stereo bass management sees the incorporation of the LFE channel?

It’s obvious in your video clips and the visuals, it didn’t happen for me though. Continuous audio on or off sounded the same and I had no fade out before 150 cut. I used an app called Tone Generator and I have the paid Pro version so I set it similar pace to yours, and slower. Getting airplay off and switching takes a minute but the tone seemed the same and pretty consistent until slowwwwed. I ran loops so listened for a bit over and over. What was weird was for kicks I touched the bass drivers of my surrounds and they weren’t participating, I had the volume up pretty good. This was continuous audio on and off. My fronts were working hard and all 3 subs were pumping. I’m listening to a 2 channel flac rip right now and my rear bass drivers are participating? I don’t airplay to my Denon so I could have a setting somewhere, I’m done for tonight

ETA: I just realized I need to go through the Apple TV somehow to test continuous audio making a difference, YouTube clip like you. Duh.

 

[JRowland]

As i mentioned before, receiver is on auto update and second to last version of Dirac.
And Yes i am sure Dirac is engaged.

I cant change distance, only lvl.
But there aint any use for it, it screews with ART, 1 dB is enough.

I can get to level adjust through the options menu on my 4800 and it works, like you I left it alone. In the settings menu it’s all locked down. I’m on auto update and I checked just now and I’m on the most current.

 

[RickS]

This thread is pretty robust and was recently reported for veering off topic. Do not have time to review in detail, but if a new thread is needed, please start and will move posts to it.

Thanks!

 

[KenMasters]

ETA: I just realized I need to go through the Apple TV somehow to test continuous audio making a difference, YouTube clip like you. Duh.

If it helps, this is the YouTube clip I used:

I was thinking about it, I have ART set up to behave more like a traditional crossover with my LS50 Metas:

In a more mixed system the issue might manifest differently.

 

[KenMasters]

This thread is pretty robust and was recently reported for veering off topic. Do not have time to review in detail, but if a new thread is needed, please start and will move posts to it.

Thanks!

I don’t think it’s off topic, but the last few pages have been about how ART goes about setting subwoofer delay and the 5ms LFE delay bug. If you feel that should be split off into a separate thread, the conversation begins here

 

[markus]

I'm pretty sure everyone using ART has noticed this or perhaps not everyone has noticed it because not everyone measures their system post ART calibration. I always measure post calibration as RCS don't always get it right.

In my experience ART does an excellent job with phase and time alignment. This particular example is for 12 point measurement calibration for a 6ft 3 seater sofa. ART's speaker time alignment is impeccable, all speakers are within 0.53 inches of each other and phase alignment is flat and my system sounds great.

I'm an enthusiast and not expert but I think ART makes my subs start super early, 15ms early(Circled in red) to accomplish its goal of optimizing based on a flat phase. It is my understanding that for subs the start of the impulse response which in my case is 15ms should be aligned at t=0 as this is when energy from the subs starts to arrive at our microphone(Ears). But since Dirac locks us out of delay adjustments post calibrations there is nothing we can do about this early start. I wish Dirac would reconsider and allow for post EQ time alignment at least so that we can correct for this.

View attachment 529642

View attachment 529643

Sorry for joining the discussion late. Did you check the excess group delay to see whether there’s an actual subwoofer delay visible, or if this is just part of Dirac’s secret sauce?

See REW help for a more detailed explanation of excess GD:

Minimum Phase

 

[Mort]

Nothing is off topic. Someone has their underwear in a bunch.