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From what I understand (and hear) DLBC is working just fine for 2.1 listening. The problem is with multichannel formats.
I enable DLBC 100% of the time when listening to stereo music, no bug there and sounds wonderful to my ears!
where i can find the DLBC feature? i got a nad 758. i never saw it .thanks!
 

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where i can find the DLBC feature? i got a nad 758. i never saw it .thanks!
It's only available on newer/higher end products.
 

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Below is an exerpt from the MSO intro page

I don’t see a reason it wouldn’t work well with DLBC to “optimize the splice” and it looks like it works well as @stef2 noted. There probably not a ton of people that have used this combo because DLBC is supposed to automate the sub array optimization process as well. So we only have early adopters waiting for a bug fix using this combo, or people that wanted to optimize a sub array larger than their DLBC capable outputs.

MSO should work fine in Bootcamp. It just crunches numbers after importing REW measurements. You can still use your existing Mac REW rig to do the measurements if you want to. You can test MSO out with the provided tutorial measurements.

View attachment 3120335
Cool, Thanks a lot. I was very much ready to move on from the miniDSP/REW combo. Way too much time spent trying to get a pretty looking graph that didnt sound any better/different than what I had before. But in considering the best approach to calibrate the 4 subs and also picking up the extra 2 channels for wides maybe its worth a look. I would have to answer the question of whether to go with option A or option B.
Option A would be to pair off either my front or Rear Subs, and use DLBC multi Sub wiht 3 channels.
Option B would be to combine all 4 subs to one output using single sub DLBC. Id only consider doing this in conjunction with MSO, as I already know the miniDSP alone isnt worth the time (imo) compared to DLBC. I know its much more time consuming, but if people say the results are better then its at least worth looking into.
 

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That is pretty interesting. One thing you might try is running the RTA function in REW and fiddling with the sub trim to see if you can get rid of that null, if you want to try and avoid remeasuring and all that jazz. You might find some luck there with even a minuscule adjustment. Any kind of adjustment can result in some pretty radical changes (and oftentimes, hardly any changes at all), and running RTA can reveal that. Bass frequencies are weird but freaking cool. One caveat: the adjustments will affect areas (that is, if you’re adjusting with the mic at the listening position, you won’t know how that is affecting the seat to your left, behind, etc.).
Thanks again for your response. As I've posted and you can see from my graphs, the +6 at 20hz doesn't include a null. In addition, it sounds better in our large room with a concrete floor. As I've said, with ARC Genesis, always re-did sub adjustments after raising their volume and, also, did the sub distance tweak, which always had a dramatic effect in my room. With the 4 SVS SB16 subs we have, don't really see how I could get better sounding bass. When I read that the DLBC problem is fixed, I will download upgrade and re-measure. However, in our system, always using direct and streaming or cable, don't hear any problems. Direct in HTP-1, with what we listen to, always means Dolby surround, except in 2 channel, when it is just stereo.
 

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Cool, Thanks a lot. I was very much ready to move on from the miniDSP/REW combo. Way too much time spent trying to get a pretty looking graph that didnt sound any better/different than what I had before. But in considering the best approach to calibrate the 4 subs and also picking up the extra 2 channels for wides maybe its worth a look. I would have to answer the question of whether to go with option A or option B.
Option A would be to pair off either my front or Rear Subs, and use DLBC multi Sub wiht 3 channels.
Option B would be to combine all 4 subs to one output using single sub DLBC. Id only consider doing this in conjunction with MSO, as I already know the miniDSP alone isnt worth the time (imo) compared to DLBC. I know its much more time consuming, but if people say the results are better then its at least worth looking into.
I’m with you and wanting to save time with with DLBC and avoiding as many manual steps as possible. This is the main reason I jumped on DLBC right away.

Regarding pairing off subs—I would not combine subs into pairs if possible as they are in different position with respect to the room and boundaries. In some cases you might get the same optimal parameters for, say, 2 front subs, but not always. The only exception I’d make is if the 2 subs were literally right on top of each other and I was out of channels. (This would make them act more like 1 bigger sub with 6db more SPL, but the tradeoff is colocating them defeats the purpose of putting subs in different location to reduce variance.)

The decision to optimize the sub array externally is simple if you would otherwise exceed your processors channel count.

Regarding whether MSO is “better” than DLBC. Of the people who have done both, I haven’t seen anyone say that DLBC gets better results for optimizing the stand alone bass array. It just saves a ton of time, and also automates the crossover splice, which is a huge bonus.

I have seen a some such as @stef2 say they did get better results with MSO for seat to seat variability of the bass array. I suspect I will get better results too, because I’m an edge case where I was hitting into Dirac eq limits and could not get the best seat to seat reduction in variance.

So for me, I‘d have 2 reasons: to get additional wide channels back on my HTP-1, and to potentially overcome some EQ limits I was hitting before with multi sub DLBC.

I’ll still use the “single sub” version of DLBC to optimize the splice from the MSO optimized array to each individual speaker. That would be extremely tedious manually.

Because of my experience with this setup, I will strongly consider hiring a professional calibrator when I build out my second setup, which will be a dedicated home theater. I will appreciate the help even more once I’ve gone through the full process myself a few times :)
 

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I’m with you and wanting to save time with with DLBC and avoiding as many manual steps as possible. This is the main reason I jumped on DLBC right away.

Regarding pairing off subs—I would not combine subs into pairs if possible as they are in different position with respect to the room and boundaries. In some cases you might get the same optimal parameters for, say, 2 front subs, but not always. The only exception I’d make is if the 2 subs were literally right on top of each other and I was out of channels. (This would make them act more like 1 bigger sub with 6db more SPL, but the tradeoff is colocating them defeats the purpose of putting subs in different location to reduce variance.)

The decision to optimize the sub array externally is simple if you would otherwise exceed your processors channel count.

Regarding whether MSO is “better” than DLBC. Of the people who have done both, I haven’t seen anyone say that DLBC gets better results for optimizing the stand alone bass array. It just saves a ton of time, and also automates the crossover splice, which is a huge bonus.

I have seen a some such as @stef2 say they did get better results with MSO for seat to seat variability of the bass array. I suspect I will get better results too, because I’m an edge case where I was hitting into Dirac eq limits and could not get the best seat to seat reduction in variance.

So for me, I‘d have 2 reasons: to get additional wide channels back on my HTP-1, and to potentially overcome some EQ limits I was hitting before with multi sub DLBC.

I’ll still use the “single sub” version of DLBC to optimize the splice from the MSO optimized array to each individual speaker. That would be extremely tedious manually.

Because of my experience with this setup, I will strongly consider hiring a professional calibrator when I build out my second setup, which will be a dedicated home theater. I will appreciate the help even more once I’ve gone through the full process myself a few times :)
In regards to the pairs. Both pairs are equidistant, but Dirac has slightly different delays on them. Like the fronts are 0 and 0.2, so I think I could get away with it. I’m less concerned about seat to seat consistency, but whatever Dirac Bass control does has been better than what I could accomplish without it and the miniDSP. It just sounds better. So, MSO may not be worth the effort in the end but I’ll at least check it out and see what it’s all about and then decide if I want to give it a shot.
I’ve got a new amp coming in a few weeks which will give me the amplification I need for wides so won’t be long before I play around with that and decide if it’s worth the hassle. In the meantime I’ll do some digging around for info on MSO starting with what you sent me.

thanks again for the help
 

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What you describe is Dirac Unison — Dirac ;) The problem I see with that approach is that satellite speakers can't be part of an optimization strategy that is based on downmixing multichannel content to a single monophonic signal. This works only below about 80Hz where humans can't localize sound sources.
Thanks for the pointer to Unison. I didn't know exactly what Unison was; now this makes more sense to me. I wish they'd put Unison on a processor we could buy, but for some reason that seems out of the cards.

It's true that the localization issue would be a problem. But I would be willing to take the hit up to a reasonable frequency, if it was the only way of getting rid of room mode effects.

Output of most satellite speakers is also highly limited in that range. I don't think it's a good idea to send LFE and all other bass content to them.
I was thinking most of that content would stay on the subs anyway, since the "mono cutoff" would occur upstream of the hpf/lpf.

So fixing the current DLBC implementation would be good enough for me right now.
I hope they can fix it, but to me it seems this problem is unsolvable with filters alone. No doubt I am missing something, since the Dirac rep said the fix is on the way. But I think the only way to really address the problem and still retain multichannel content is to do some kind of signal injection. Where the speakers do double-duty as active bass absorbers, and the processor injects "termination signals" into other speakers to absorb the mode-freq output from a source channel. Kind of like noise cancellation.
 

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Options like you are suggesting add a layer of complexity to the DLBC solution, most likely beyond the average user's level of expertise. The compelling reason to use DLBC is that it should provide excellent results as automatically as possible.
I certainly agree that this should be as easy as possible. But the main purpose is to save tuning time (weeks? months? or even more), not necessarily to prevent a more knowledgable user from tweaking a few parameters optionally, if they know better. Using a default value that is optionally adjustable works for both types of users, I think.

Another parameter that should be adjustable for the informed user is the sub/main crossover freq. Since DLBC measures on small signals, it can't possibly know that my mids will blow out at higher volumes if it auto-sets the xover at 60 Hz (as an example). But I know that because I chose the drivers and I know their xmax and thermal handling etc, and I know how loud I want to play the system. So the informed user should be able to optionally set a minimum xover point that DLBC doesn't violate when choosing the xover.
 

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Can't they fix the DLBC issue by only applying the all pass filters to the satellites and not to the subwoofers? The problem if I read it correctly is that each satellite want to have its own all pass filter applied to the sub at which stage this clash can happen.
 

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Discussion Starter · #4,292 ·
Can't they fix the DLBC issue by only applying the all pass filters to the satellites and not to the subwoofers? The problem if I read it correctly is that each satellite want to have its own all pass filter applied to the sub at which stage this clash can happen.
Much better results can be had if there's a complementary all-pass in the sub channel.

You can test this out using MSO. Measure single speaker/sub responses, plug them into a new project and optimize with 2nd order all-passes.
 

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Much better results can be had if there's a complementary all-pass in the sub channel.

You can test this out using MSO. Measure single speaker/sub responses, plug them into a new project and optimize with 2nd order all-passes.
Sure but that all-pass on the subwoofer channel has to be unlinked from the satellites which is where things are going wrong with the current implementation.
 

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Discussion Starter · #4,294 ·
Sure but that all-pass on the subwoofer channel has to be unlinked from the satellites which is where things are going wrong with the current implementation.
Nothing would go wrong if the implementation would look like the 2nd signal flow I've posted earlier.

All-pass filters don't need to be "linked", just like high- and low-pass filters don't necessarily need to be "linked". Filters need to be optimized against each other so the response is as flat as possible. This doesn't necessarily result in filter settings that are direct "mirror images".
 

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Hi everyone,

we at Dirac appreciate your commitment and attention in regards to our Bass Control algorithm. We have taken this subject very seriously from day one, even if we have not publicized our process in working on solutions. Now, following extensive internal testing and consultation with a number of affected users, we have sufficient data and understanding to offer two solutions, both of which we expect be available within a few weeks publicly as well as free of charge. Please see the attached document for more info on these. However, if you do not feel satisfied with these solutions and would like to return the product anyway, we, as always, offer full refunds for your purchase. Thank you all for your attention and care. Without you, Dirac Live would not be the product it is today. Thanks again and we will keep you updated.


Update on bass control issue

For some use cases it has been determined that an unexpected amount of correlation is present between the source channels which can lead to cancellations in the digital domain. This mainly seems to concern some upmixed two channel cases, but can also be observed if a low frequency signal is panorated front to back in object audio formats.

There are several options to work around this, each with their own set of advantages and concerns. We are currently considering to add two options that allows a user to choose between three different filter design schemes for bass control:

Co-optimize the subwoofers, then apply traditional bass management.

Advantage: Multiple subwoofers will be co-optimized from a spatial variation perspective
Drawback: Main to sub integration will be uncontrolled

Co-optimize the subwoofers, then use fewer degrees of freedom to work with the phase. More specifically, use a single allpass filter for the redirected bass and individual allpass filters for the full range channels

Advantage: Multiple subwoofers will be co-optimized from a spatial variation perspective. Main to sub integration is controlled. Identical to option 3 for stereo use cases, better than option 3 if channels are correlated, worse if they are not.
Drawback: Having non complementary allpass filters can result in undesired phase shifts significantly above the cross over point, resulting in distorted imaging from pairs of speakers, other than the front pair.
Note: The exact impact and frequency of occurrence of the drawback above must be investigated further.

Bass Control as today

Advantage: Works great for many use cases, like stereo playback with multiple subwoofers, traditional channel based PCM audio.
Drawback: Can have issues with upmixed stereo content, and if present in the content, moving low frequency sources.

The plan is to allow users the choice between these three that is used for a particular filter set. This allows a user to have multiple filter setting (assuming the equipment have the filter storage to upport this) that can be switched between depending on content, if desired.

We hope to have option 1 in beta within the next two weeks. For option 2 we are in the process of implementing that still, and will get back to you with an expected availability date once we have more information.

We have also made a document available reasoning around this, in technical terms, for a stereo use case and a channel based multi channel use case. It does not consider the stereo upmixing use case however.

Dirac Research
 

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Hmmm not what I was hoping to hear :(
 

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This seems to be in line with what other have been suggesting. The different use case options was something I suggested a few days back, which certainly adds another level of complexity to the whole thing.

All in all it seems like a viable solution, and still easier than any other alternative. Some may see it as not worth the investment, but that's up to each person to decide.
 

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This seems to be in line with what other have been suggesting. The different use case options was something I suggested a few days back, which certainly adds another level of complexity to the whole thing.

All in all it seems like a viable solution, and still easier than any other alternative. Some may see it as not worth the investment, but that's up to each person to decide.
I'm trying to determine if there's any advantages for my setup and if I'll be greatly affected by these issues. I have a 9.2.6 system that's really for movies. The bit of music I listen to in the dedicated theater is minimal at best and not critical in nature in general. I upmix music with Auro3D or DSU.
 
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I'm trying to determine if there's any advantages for my setup and if I'll be greatly affected by these issues. I have a 9.2.6 system that's really for movies. The bit of music I listen to in the dedicated theater is minimal at best and not critical in nature in general. I upmix music with Auro3D or DSU.
I’m assuming the consensus would be to utilize the new beta option coming soon. That would optimize the subwoofers with each other but not optimize the splice to the mains. That would work for both music and movies.
If you opt to use the existing version then it will optimize subs and subs to mains integration. It will be fine for movies except for a few instances of cancellations caused by panning LFE content. I’d expect this wouldn’t be recommended by most though. However, this definitely shouldn’t be used for upmixed music.

The last option which sounds like it’s going to take them time to implement is probably the best solution in theory, but I’m not sure if that can be fully determined until it’s released and the REW army has at it. But if I understand flax correctly then it will be like a middle ground between the other two options.

Lastly, for 2 channel music (not up mixed) the answer will be to use DLBC in its current form.
 

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I’m assuming the consensus would be to utilize the new beta option coming soon. That would optimize the subwoofers with each other but not optimize the splice to the mains. That would work for both music and movies.
If you opt to use the existing version then it will optimize subs and subs to mains integration. It will be fine for movies except for a few instances of cancellations caused by panning LFE content. I’d expect this wouldn’t be recommended by most though. However, this definitely shouldn’t be used for upmixed music.

The last option which sounds like it’s going to take them time to implement is probably the best solution in theory, but I’m not sure if that can be fully determined until it’s released and the REW army has at it. But if I understand flax correctly then it will be like a middle ground between the other two options.

Lastly, for 2 channel music (not up mixed) the answer will be to use DLBC in its current form.
My gut is, I have really good bass right now, so just leave it alone and ignore the tinker gene.
 
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