Dirac New Spatial Room Correction Software

Matthew J Poes

Matthew J Poes

Audioholic Chief
Staff member
For those who aren't quite clear how the cancelation works, let me share a related idea known as the double bass array.



When this idea was developed, it worked well at completely eliminating bass modes in a room at any location. It had two problems, first, it made the room effectively anechoic at low frequencies and it only worked below 80hz or so (whatever the subwoofer crossover point was). It was also impractical.

Dirac us using the same underlying principles, but because we still maintain reproduction of the direct sound from the speaker sources (and we don't cancel that), we don't lose spatial bass. We also can make it work much higher since we rely on surround speakers and subwoofers for this.
 
TLS Guy

TLS Guy

Seriously, I have no life.
For those who aren't quite clear how the cancelation works, let me share a related idea known as the double bass array.



When this idea was developed, it worked well at completely eliminating bass modes in a room at any location. It had two problems, first, it made the room effectively anechoic at low frequencies and it only worked below 80hz or so (whatever the subwoofer crossover point was). It was also impractical.

Dirac us using the same underlying principles, but because we still maintain reproduction of the direct sound from the speaker sources (and we don't cancel that), we don't lose spatial bass. We also can make it work much higher since we rely on surround speakers and subwoofers for this.
Thank you for that explanation, now I understand where you are coming from.

However if this is going to require a multiplicity of speakers channels, that is not practical in the home. The spaces need to sound good and be livable. The other thing with the number of channels recently proposed by "Experts" on a recent Audioholics YouTube video that concern me is this. You can bet there will be a problem somewhere often, given that complexity and huge increase in electronics especially amps. So I maintain this is NOT practical.

Now to switch gears I do not seem to have the magnitude of bass problems the rest of you seem to wrestle with. I think that comes for two reasons, the first is that my main systems have been TL based for over 60 years, and I have a vast experience with them now. All my speakers except the two surrounds and the four ceiling speakers which are sealed, are aperiodically damped transmission lines. I have had many experienced engineers use and visit my systems over the years, and the comment is that the bass quality is what separates my systems from the rest.

When I was still in practice in Grand Forks, Bob Carver came to deliver and set up his ribbon system that one of my colleagues had purchased. He had heard about my system, the speakers were then the speakers that are now my rear backs. He had a prototype of his Sunfire Woofer with him.

Anyhow, he was enthralled and stayed for hours and sampled lots of musical selections. Needless to say his Sunfire sub, which I hooked up was no match for the TLs.

I am not sure of what the physics is behind all this, but I am convinced there is something different about the way a pipe couples to a room.

I have spent quite a bit of time with organ builders over the years. They have demonstrated to me how the character of pipes is totally different from loudspeakers.

The pipe uniformly fills large spaces, and wherever you are in the room the sound is uniform, especially the bass. Where as use speakers and the sound falls away fast as you move further away from the speakers. Organ builders refer to this phenomenon of pipes as encirclement. I know for certain this a real phenomenon. I don't believe it has been investigated the way it should have been.

This also applies to TL speakers I believe. TL speakers do seem to fill rooms evenly in the lower decades and seem to not excite room modes to the extent other forms of bass loading do. I really have no idea why, but others have also noted this.

I should say, that all my speaker are run full range except the four ceiling speakers which are crossed over. The right and left speakers are fully integrated full range speakers down to 20 Hz with a prodigious bass output. The center rolls off at 47 Hz second order, the surrounds have an F3 of 52 Hz and roll off second order,
The rear backs roll off around 27 Hz and still have plenty of output to 20 Hz.

I have never found the system produce even remotely close to boomy reproduction. The room is on the whole evenly filled with bass, with a slight elevation in the rear of the room. My measured room responses confirm a very even sound distribution in the bass decades and throughout the audio band for that matter. This is without any EQ other than levelling the active speakers and correctly setting BSC, which due to design is easily adjustable. In addition properly mixing the Sub/LFE channels with the BSC signal to the long lines of the left and right speakers. There is no other electronic manipulation.

I really doubt things would be improved adding channels and complex algorithms.

I would here pay tribute to the work and research of George Augspurger and his development of an accurate design model for TL loudspeakers. That has made my life a lot easier! I feel honored and privileged, that he has entrusted me with the body of that work and make it freely accessible to all.

Mathew, you are welcome to visit here any time, and hear first hand. With people advocating such complex solutions, I think all avenues need to be explored. I think George's work on TLs has been disgracefully ignored. I am certain you would find a visit well worth your while.
 
CreoleDC

CreoleDC

Junior Audioholic
I'm really impressed with Audyssey for bass management I think all of the big boys Audyssey ARC Dirac are really good for bass management purposes
Not according, to some who don't use ARC at all. Big boy, lil boys alike. :cool:
 
Replicant 7

Replicant 7

Audioholic Samurai
No bathroom inside my HT. But just right outside of my HT. :D

Room Corrections and especially Dirac have gotten many audiophiles’ attentions especially in recent years.

Even Denon/Marantz have been rumored to offering Dirac.

My position on this is, tell everyone to try it for themselves just like everything else in life.

Personally, there’s no way I’m spending $5K for any of these features (no matter what they are) if I can do it for free or for less. :D
Than you ain't running with the Big boys. You gotta have Dirac!! Guess it's better to have 10 sub's and one 5 channel amp to drive them.

Than jump up to upgrade to a real surround sound processor. You staying in the middle huh?

Stop buying up least properties to rent on the west coast. Or next time you do buy a mortgage factor in for that Storm audo/video processor. Now that would be running with the Big boys.:D
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
I do not seem to have the magnitude of bass problems the rest of you seem to wrestle with.
Correction - “SOME of you”, not “the REST of you”. :D

I never had any kind of lack of bass or bass issues even when I first started out in this hobby.

I didn’t even know people had bass problems until I joined AH. :D

So I would say that MANY people don’t have any bass issue.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Than you ain't running with the Big boys. You gotta have Dirac!! Guess it's better to have 10 sub's and one 5 channel amp to drive them.

Than jump up to upgrade to a real surround sound processor. You staying in the middle huh?

Stop buying up least properties to rent on the west coast. Or next time you do buy a mortgage factor in for that Storm audo/video processor. Now that would be running with the Big boys.:D
Mike, Dirac, other RC and Auto Multi-Sub EQ are for people who wrestle with bass and other sound problems. :D

I’m all good here, bro. Let the good times roll. :cool:

But yes, all these features are great options for people who want them. :D
 
CreoleDC

CreoleDC

Junior Audioholic
Correction - “SOME of you”, not “the REST of you”. :D

I never had any kind of lack of bass or bass issues even when I first started out in this hobby.

I didn’t even know people had bass problems until I joined AH. :D

So I would say that MANY people don’t have any bass issue.
Just really Good high quality drivers, speakers and subs., Plus a dedicated HT room designed for Your System! Didn't you and Doc, specifically build your dedicated HT rooms first?

Then added your system, speakers, gear one or two high quality amps with high quality speakers. Yeah makes sense to me to do that right first.

The room makes it a Whole lot easier to manage the rest. One day I'll have me a dedicated home theater room only.

I do envy you guys that have those dedicated HT rooms. Oh the possibilities my imagination can only Wonder. Thank you Andrew and @TLS Guy "Doc" for sharing you'll experience and knowledge on setups, room, and Audio/Video gear.

Speaking for myself, that's why I follow you two around in here on AH. Besides Gene, you two and few others are very practical in use of and knowledgeable with this hobby.
 
Trell

Trell

Audioholic Spartan
Mike, Dirac, other RC and Auto Multi-Sub EQ are for people who wrestle with bass and other sound problems. :D

I’m all good here, bro. Let the good times roll. :cool:

But yes, all these features are great options for people who want them. :D
Most people will have bass problems as their rooms are not designed and built for listening to audio, or simply cannot put the speakers and MLP in the right positions.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Correction - “SOME of you”, not “the REST of you”. :D

I never had any kind of lack of bass or bass issues even when I first started out in this hobby.

I didn’t even know people had bass problems until I joined AH. :D

So I would say that MANY people don’t have any bass issue.
I stand corrected!
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Most people will have bass problems as their rooms are not designed and built for listening to audio, or simply cannot put the speakers and MLP in the right positions.
Maybe we should start a poll to see just how MANY people have "bass problems".

Unless their rooms have no area rugs/carpets and made of all hard/reflective surfaces, MANY people's bass and room acoustics are fine in their TRADITIONAL rectangular rooms on carpets, sofas, curtains, etc.

I won't say "MOST" people. :D
 
Last edited:
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Just really Good high quality drivers, speakers and subs., Plus a dedicated HT room designed for Your System! Didn't you and Doc, specifically build your dedicated HT rooms first?

Then added your system, speakers, gear one or two high quality amps with high quality speakers. Yeah makes sense to me to do that right first.

The room makes it a Whole lot easier to manage the rest. One day I'll have me a dedicated home theater room only.

I do envy you guys that have those dedicated HT rooms. Oh the possibilities my imagination can only Wonder. Thank you Andrew and @TLS Guy "Doc" for sharing you'll experience and knowledge on setups, room, and Audio/Video gear.

Speaking for myself, that's why I follow you two around in here on AH. Besides Gene, you two and few others are very practical in use of and knowledgeable with this hobby.
Yeah, I even did my HT room per one of the Audio Engineering Society's Room Acoustic Formulas 1H: 1.57W: 1.87L

So if the Ceiling height is 14', then it's 14' H x 22' W x 26' L, which is the dimensions for my HT. :D

But according to other audio experts like the late Siegfried Linkwitz and Peter Aczel, many traditional rectangular rooms with carpets/area rugs, sofas, curtains, etc., will be just fine for rooms acoustics.
 
Trell

Trell

Audioholic Spartan
Maybe we should start a poll to see just how MANY people have "bass problems".

Unless their rooms have no area rugs/carpets and made of all hard/reflective surfaces, MANY people's bass and room acoustics are fine in their TRADITIONAL rectangular rooms on carpets, sofas, curtains, etc.

I won't say "MOST" people. :D
I guess you’ve a big listening room, but smaller rooms typically have huge dips and peaks, as you might know. :D

Rugs and carpets does nothing for the bass.;)
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
I guess you’ve a big listening room, but smaller rooms typically have huge dips and peaks, as you might know. :D

Rugs and carpets does nothing for the bass.;)
The rugs and carpets can affect the overall sound acoustics and quality perception, which can indirectly affect the perception of the bass quality.
 
CreoleDC

CreoleDC

Junior Audioholic
Yeah, I even did my HT room per one of the Audio Engineering Society's Room Acoustic Formulas 1H: 1.57W: 1.87L

So if the Ceiling height is 14', then it's 14' H x 22' W x 26' L, which is the dimensions for my HT. :D

But according to other audio experts like the late Siegfried Linkwitz and Peter Aczel, many traditional rectangular rooms with carpets/area rugs, sofas, curtains, etc., will be just fine for rooms acoustics.
That's something you've never shared with me, at least I don't remember as of lately. I didn't know you followed up on Linkwitz and Aczel. You also having a engineers degree, Now you tell me this! You been holding back on me. :).

You can talk up to me ya know. I may not fully understand, the technical engineering jargon. But I do learn.... slowly though. it's freaking awesome Andrew!
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
That's something you've never shared with me, at least I don't remember as of lately. I didn't know you followed up on Linkwitz and Aczel. But you also having a engineers degree, Now tell me this! You been holding back on me. :).

You can talk up to me ya know. I may not fully understand, the technical engineering jargon. But I do learn.... slowly though. it's freaking awesome Andrew!
Oh, but you clearly remember that COW eating grass on my front lawn? :D

Yeah, I've mentioned my HT rooms' AES formula many times on AH. But most people don't have any reaction to it every time I mentioned it. :D

I guess formulas aren't as MEMORABLE as COWS on your front lawn. :D

Or CHICKENS on your farm. :D

 
Last edited:
mtrycrafts

mtrycrafts

Seriously, I have no life.
Yeah, I even did my HT room per one of the Audio Engineering Society's Room Acoustic Formulas 1H: 1.57W: 1.87L

So if the Ceiling height is 14', then it's 14' H x 22' W x 26' L, which is the dimensions for my HT. :D

But according to other audio experts like the late Siegfried Linkwitz and Peter Aczel, many traditional rectangular rooms with carpets/area rugs, sofas, curtains, etc., will be just fine for rooms acoustics.
Well, your room will stand up to both methods. :D
Just hope it won't get tired standing up.
 

Latest posts

newsletter

  • RBHsound.com
  • BlueJeansCable.com
  • SVS Sound Subwoofers
  • Experience the Martin Logan Montis
Top