Second generation Dirac Live Room EQ coming

[DonH56]

Yah, mine are essentially set up as a mono group but I use the two mono outputs to handle the front pair and rear pair independently (mainly to let the Emo do the phase tweaking). My pre/pro can configure the subs as mono, dual mono, or stereo, but since DL happens before BM integration is tricky.

I have been back and forth on stereo vs. mono subs endlessly. Last time around there just wasn't anything I was hearing that led me to go back to stereo subs and I was tired of all the mucking around to integrate stereo subs so a mono group it is.

 

[dallasjustice]

But, it should be interesting to see what Dirac does in the new version.

I agree. Based on the descriptions I’ve read, Unison seems to be designed to use multiple speakers to control modal ringing as well as smoothing out the non-minimum phase dips. If that’s the basic Unison concept, then bass management using multiple subs must be a part of the solution. At least I hope this is the case because I want to be able to use my existing multi sub array with Unison. IOW, I don’t want to buy a bunch of new speakers just to see what Unison does.

 

[jhaider]

Is Dirac indeed having problems with proper implementation by manufacturers? Please share what you know.

All of the bass management implementations I know of right now are done wrong. Arcam's has gotten iteratively better, but I believe their underlying BM is still the obsolete THX style, which requires lots of extracurricular work to hammer into place when you're not using THX style speakers. NAD rolls off the LFE channel a half octave too early. I do not know about Datasat or Emotiva, because I have followed them less closely.

 

[Fitzcaraldo215]

All of the bass management implementations I know of right now are done wrong. Arcam's has gotten iteratively better, but I believe their underlying BM is still the obsolete THX style, which requires lots of extracurricular work to hammer into place when you're not using THX style speakers. NAD rolls off the LFE channel a half octave too early. I do not know about Datasat or Emotiva, because I have followed them less closely.

Dirac itself does no bass management currently. That is left to the AVR/prepro/processor to implement. So, it is not a Dirac problem, and there have been occasional attempts by some to place BM after Dirac in the signal path, rather than before, the latter of which would be the correct way.

I agree that THX is obsolete. But, I am not seeing incorrect implementations of BM in many AVR/prepros. My old Integra DHC-80.2, for example, allowed THX settings and its fixed 80Hz xover, or it allowed user selected, non-THX xovers, "large" vs. "small" channels, choice of LPF of LFE, etc. The Integra was price-wise toward the lower end of available prepros for quite some time. I also examined a friend's Marantz 8801 prepro, and I saw (or heard) no problems with their implementation of BM, which was similar to the competing Integra.

Toole describes the prototypical, standard BM as commonly implemented in his latest book. He has no major complaints about it, though obviously bass channels can be further optimized beyond the scope of basic BM via multiple subs, more sophisticated optimization and EQ schemes, etc. to better deal with room acoustics. He prefers summed mono bass, even where multiple subs are deployed. He sees no empirical listener benefit to stereo bass beyond its deployment of multiple subs.

I just don't see a big problem with that straightforward, basic standard BM: symmetrical xovers on all channels, possibly at different frequency for each channel, and yielding a summed mono sub channel including any LFE channel from the input. That is the BM style I now use on my MediaPC implemented in JRiver ahead of Dirac in the signal path. That can be fine tuned as desired for timing, phase, etc. And, note that I use it primarily for music listening as 2.1, 3.1, 5.1 or 7.1 output with all input sources. It works fine and sounds great to me, and the sub is sonically unobtrusive and well integrated. The system sounds much, much better with the sub than does running all channels full range. And, I play a lot of Haydn String Quartets, solo piano music, large scale orchestral works, jazz and even a little rock.

I am not familiar with Arcam implementations, but Kal cited problems with it in a previous post. Not sure what the problems might be. Or, for that matter, what is wrong with most implementations, as you state. They do not seem be hung up on THX, and many offer considerable flexibility.

 

[oivavoi]

All of the bass management implementations I know of right now are done wrong. Arcam's has gotten iteratively better, but I believe their underlying BM is still the obsolete THX style, which requires lots of extracurricular work to hammer into place when you're not using THX style speakers. NAD rolls off the LFE channel a half octave too early. I do not know about Datasat or Emotiva, because I have followed them less closely.

What do you see as the right way of doing it?

 

[DonH56]

It is only an issue with Dirac Live and where in the chain BM is applied when using it, not a general problem (AFAIK, though I have read mixed reviews on how say Audyssey handles multiple subs).

 

[dallasjustice]

Unison could be a fundamental shift for BM. It probably will be unlike any off the shelf DSP product.

When speakers are used to cancel low frequency room modes, the bass clarity is much better than the minimum phase mode inversion filter approach pretty much everyone currently employs in their software.

 

[Brad]

I have thought about using multi sub optimiser (MSO) to generate the parameters for a unison type approach. That is, in addition to my 2 subs, the 4 surround speakers are treated as additional subs in the 40-80Hz range.
Haven't tried it yet though

 

[dallasjustice]

I don’t think MSO is the same as Unison approach.

My understanding of Unison is that opposing speakers are used to cancel modes. That’s not what MSO does.

I have thought about using multi sub optimiser (MSO) to generate the parameters for a unison type approach. That is, in addition to my 2 subs, the 4 surround speakers are treated as additional subs in the 40-80Hz range.
Haven't tried it yet though

 

[jhaider]

Dirac itself does no bass management currently. That is left to the AVR/prepro/processor to implement. So, it is not a Dirac problem,

I look at it differently. The above is the problem! How can you correct the biggest problems in the room when one of the most important aspects of that problem is completely unaccounted for?

I think one reason Anthem's auto-EQ generally sounds better than competitively-priced systems* is that ARC unifies room correction and bass management.

My use of "THX" was imprecise. What I meant was the typical AVR or SSP bass management with a 2nd order highpass and 4th order lowpass. I think of that as "THX" because it makes some sense as a starting point when you don't have DSP informed by measurements and you expect the speakers to have a closed box rolloff with a cutoff around the crossover point. Today I think that approach is obsolete.

Andrew Jones has an interesting take on bass management, used on the Elac compact integrated amp. There will be more detail on that soon.

*I am not comparing ARC to SFM or RoomPerfect. For one thing, I have never used either of those systems.

 

[Fitzcaraldo215]

I look at it differently. The above is the problem! How can you correct the biggest problems in the room when one of the most important aspects of that problem is completely unaccounted for?

I think one reason Anthem's auto-EQ generally sounds better than competitively-priced systems* is that ARC unifies room correction and bass management.

My use of "THX" was imprecise. What I meant was the typical AVR or SSP bass management with a 2nd order highpass and 4th order lowpass. I think of that as "THX" because it makes some sense as a starting point when you don't have DSP informed by measurements and you expect the speakers to have a closed box rolloff with a cutoff around the crossover point. Today I think that approach is obsolete.

Andrew Jones has an interesting take on bass management, used on the Elac compact integrated amp. There will be more detail on that soon.

*I am not comparing ARC to SFM or RoomPerfect. For one thing, I have never used either of those systems.

Not sure if Anthem ARC is indeed better sounding than other approaches. It is tough to make meaningful comparisons in such a way as to get the mike positions identical during calibration. A close friend uses ARC on an Anthem D2V prepro, and it is good, as advertised, but it also has some weaknesses, I think.

Sean Olive did like ARC in his published comparison, but that was basically about the different target curves used by different tools. David Rich at the Secrets site also liked it, partly because of the integration between BM and ARC. I like that idea myself, and someday we might see more of it deployed. But, at least some of that advantage can be obtained by manually tweaking BM, EQ, etc. with independent measurements. Rich will be doing a piece on tweaking Dirac, as he has done for ARC. And, some tools for the PC platform, like Acourate, have extensive features to parametrically control and integrate the EQ with BM.

As I said, though, I am quite happy with Dirac Live used with basic, but flexible bass management.

 

[Chuck Gerlach]

The Datasat RS20i does have a more flexible implementation of BM. In addition to the crossover point you can select slope (12 or 24 and yes or no on high-pass). Furthermore, and external to BM, you can apply high or low pass filters to any channel ( 6db/oct up to 48db/oct; with a choice of Butterworth, Bessel, or Linkwitz-Riley). It, on occasion, can be overwhelming, with so many choices, and combinations and permutations. But for those of us who are diddlers/tweakers at heart, a dream come true.

And I am more than comfortable that the implementation of DiracLive is done correctly. But to the point of this thread, I have no idea how long or if Datasat will implement these new Dirac capabilities on their two platforms (RS20i and LS10)

 

[jhaider]

Not sure if Anthem ARC is indeed better sounding than other approaches. It is tough to make meaningful comparisons in such a way as to get the mike positions identical during calibration. A close friend uses ARC on an Anthem D2V prepro, and it is good, as advertised, but it also has some weaknesses, I think.

Sean Olive did like ARC in his published comparison, but that was basically about the different target curves used by different tools. David Rich at the Secrets site also liked it, partly because of the integration between BM and ARC. I like that idea myself, and someday we might see more of it deployed. But, at least some of that advantage can be obtained by manually tweaking BM, EQ, etc. with independent measurements. Rich will be doing a piece on tweaking Dirac, as he has done for ARC. And, some tools for the PC platform, like Acourate, have extensive features to parametrically control and integrate the EQ with BM.

As I said, though, I am quite happy with Dirac Live used with basic, but flexible bass management.

It is often asserted that one can't make meaningful comparisons without putting the microphones in the same place. I have always wondered why. If room correction system requires extraordinarily precise microphone placement to confirm its effect, I think the best word to describe that system is "unstable."

In fact, my experience measuring the effect of room correction systems suggests precise microphone positioning is unimportant. Let me give you two examples, the measurements of Audyssey XT32 in my reviews of the Marantz AV7702 SSP and Denon AV-X4100 AVR.

https://hometheaterhifi.com/reviews...rantz-av7702-surround-sound-processor-review/
https://hometheaterhifi.com/reviews...eceivers/denon-avr-x4100-a-v-receiver-review/

Sorry, SECRETS does not have links for sub-sections. You have to scroll down.

To summarize, in both cases calibrated Audyssey conformed the sound power to Audyssey's target curve. Perhaps there would have been more error with less well behaved speakers. I do not know, and have no interest in testing that case.

In both cases, I took the Audyssey calibration measurements at the positions indicated on the TV. D+M's GUI does a good job of walking you through the Audyssey calibration process. My confirmatory measurements were taken in a 6-point bubble around the primary seat (Geddes and Blind sound power method). I did not document the specific microphone locations during the AV7702 review, so I could not have copied them for the AV-X4100 review even if I had wanted to. Yet compare the results! The variances are well within measurement error. That is even more remarkable when you consider that the calibration microphones were different, and the Audyssey tower microphones are not individually calibrated.

Also, I believe that ARC came out statistically no different from no EQ in the Olive study with B&W speakers. The systems that beat no EQ were, from memory, the two different Harman systems and whichever of RoomPerfect or Trinnov was tested. Audyssey was worse than no EQ. I think Anthem's subsequent updates to their target curve fixed the bass problems Olive measured. Note also that Olive tested a wide bandwidth speaker, not a bass managed system.

Lastly, while I agree in principle with you that "at least some of that advantage [from integrated BM and EQ] can be obtained by manually tweaking BM, EQ, etc. with independent measurements," who wants to do that if you don't have to? Practically speaking, even most techie-inclined listeners will just run the calibration and judge resulting the sound quality. At most, one will play with the target curves in Dirac, ARC, or the Audyssey app. I think the bottom line is that room correction and bass management both substantially apply to the same speakers operating over the same passband. Therefore, they should not be considered in isolation from one another.

 

[amirm]

My experience with Audyssey has been the opposite. Running it in sequence it would generate different results. It was quite frustrating as it with severely interfere with experimentation.

 

[Blumlein 88]

My experience with Audyssey has been the opposite. Running it in sequence it would generate different results. It was quite frustrating as it with severely interfere with experimentation.

Yes, my experience was similar. Without moving the mike. Audyssey also hasn't sounded good to me. I don't think of the several times I tried using it that I would rate the result as an improvement. Dirac, using various Tact gear, and doing measurements to implement parametric EQ all resulted in improved sound.

 

[Fitzcaraldo215]

It is often asserted that one can't make meaningful comparisons without putting the microphones in the same place. I have always wondered why. If room correction system requires extraordinarily precise microphone placement to confirm its effect, I think the best word to describe that system is "unstable."

In fact, my experience measuring the effect of room correction systems suggests precise microphone positioning is unimportant. Let me give you two examples, the measurements of Audyssey XT32 in my reviews of the Marantz AV7702 SSP and Denon AV-X4100 AVR.

https://hometheaterhifi.com/reviews...rantz-av7702-surround-sound-processor-review/
https://hometheaterhifi.com/reviews...eceivers/denon-avr-x4100-a-v-receiver-review/

Sorry, SECRETS does not have links for sub-sections. You have to scroll down.

To summarize, in both cases calibrated Audyssey conformed the sound power to Audyssey's target curve. Perhaps there would have been more error with less well behaved speakers. I do not know, and have no interest in testing that case.

In both cases, I took the Audyssey calibration measurements at the positions indicated on the TV. D+M's GUI does a good job of walking you through the Audyssey calibration process. My confirmatory measurements were taken in a 6-point bubble around the primary seat (Geddes and Blind sound power method). I did not document the specific microphone locations during the AV7702 review, so I could not have copied them for the AV-X4100 review even if I had wanted to. Yet compare the results! The variances are well within measurement error. That is even more remarkable when you consider that the calibration microphones were different, and the Audyssey tower microphones are not individually calibrated.

Also, I believe that ARC came out statistically no different from no EQ in the Olive study with B&W speakers. The systems that beat no EQ were, from memory, the two different Harman systems and whichever of RoomPerfect or Trinnov was tested. Audyssey was worse than no EQ. I think Anthem's subsequent updates to their target curve fixed the bass problems Olive measured. Note also that Olive tested a wide bandwidth speaker, not a bass managed system.

Lastly, while I agree in principle with you that "at least some of that advantage [from integrated BM and EQ] can be obtained by manually tweaking BM, EQ, etc. with independent measurements," who wants to do that if you don't have to? Practically speaking, even most techie-inclined listeners will just run the calibration and judge resulting the sound quality. At most, one will play with the target curves in Dirac, ARC, or the Audyssey app. I think the bottom line is that room correction and bass management both substantially apply to the same speakers operating over the same passband. Therefore, they should not be considered in isolation from one another.

I guess I view the mike calibration process as sampling the room's actual response, of which our ears also capture a sampling while listening. So, samples captured at one location will usually differ in response from those at other locations, as is well known in acoustics. Multipoint averaging will smooth out much, but not all, of these differences.

One multipoint calibration test tone sweep is likely to generate a different averaged response than a second sweep with the same calibration tool if the mic positions differ. Deviation from the same target curve will therefore differ, as will correction applied, as will measured corrected response, as will subjective audibility, even if our ears on listening could be assured to be in the exact same position.

I don't mean to exaggerate this, and, with some care, the effect can be minimized. Plus, the advantages of room EQ are there in abundance with most any competent EQ tool. It might also be less an issue with higher frequencies than with lower. But, if comparing two completely different calibration tools, mike positioning during the calibration sweep is just another possible source of variation in measured or audible results, on top of numerous other possible issues, like target curve differences, algorithmic differences, hardware platform differences, etc., etc.

So, bottom line, I think it is very difficult to get a solid, apples-to-apples comparison between differing room EQ tools, either via measurement or by listening tests. I think measurements and analysis, such as you have done in your reviews, is still incredibly useful, as is understanding the known characteristics and features of a particular approach.

Good job on those reviews, by the way!

 

[Fitzcaraldo215]

My experience with Audyssey has been the opposite. Running it in sequence it would generate different results. It was quite frustrating as it with severely interfere with experimentation.

You know, I had the same experience. Lazy me. I calibrated Dirac once years ago and I have not redone it. I did recalibrate a friend's Dirac system several times, and I heard no huge differences that I could recall.

I know Audyssey touted their unique, proprietary "fuzzy logic" multi-mic-point averaging scheme. I wonder if that might be the source of this fairly widely reported instability in results of Audyssey calibrations.

 

[jhaider]

My experience with Audyssey has been the opposite. Running it in sequence it would generate different results. It was quite frustrating as it with severely interfere with experimentation.

My intention was not to defend Audyssey. I have strong reservations about their target curve, and cannot fathom why an 8dB boost at 22kHz is even allowed. But I will say this: I have experienced issues with Audyssey calibration stability with past versions. I was dreading a repeat of these issues with both D+M units. I was pleasantly surprised that their calibrations were so stable. I was also impressed that the on-screen display of the EQ curve correlated very well to my inverse curve measurements.

One multipoint calibration test tone sweep is likely to generate a different averaged response than a second sweep with the same calibration tool if the mic positions differ. Deviation from the same target curve will therefore differ, as will correction applied, as will measured corrected response, as will subjective audibility, even if our ears on listening could be assured to be in the exact same position.

My results are in opposition to that assertion: the same room correction software running on two different components from different nameplates, months apart, using different calibration microphones (same measurement setup)...and very small variance in an acoustic measurement.

 

[Blumlein 88]

My intention was not to defend Audyssey. I have strong reservations about their target curve, and cannot fathom why an 8dB boost at 22kHz is even allowed. But I will say this: I have experienced issues with Audyssey calibration stability with past versions. I was dreading a repeat of these issues with both D+M units. I was pleasantly surprised that their calibrations were so stable. I was also impressed that the on-screen display of the EQ curve correlated very well to my inverse curve measurements.



My results are in opposition to that assertion: the same room correction software running on two different components from different nameplates, months apart, using different calibration microphones (same measurement setup)...and very small variance in an acoustic measurement.

I haven't used Audyssey in recent incarnations as results earlier were so poor. Maybe it has improved. I hope so. Many people used the earlier version and said they didn't like room correction based upon their experience with Audyssey.

 

[jhaider]

I haven't used Audyssey in recent incarnations as results earlier were so poor. Maybe it has improved. I hope so. Many people used the earlier version and said they didn't like room correction based upon their experience with Audyssey.

Calibration stability has improved. The target curve has not changed. So to the extent those poor results came from not preferring the target curve, there is no change. To the extent those poor results came from calibration variance, there may be a change.

Audyssey also has an iPhone app now that allows some target curve adjustments. Significantly, I believe it also allows restricted-bandwidth correction, like Dirac and ARC. I have not used it, so I am not familiar with its capabilities or quirks.