Subwoofer With DIRAC 2 channel version

[dallasjustice]

I am interested in adding a single mono sub to my full range 2 channel system using my DIRAC 2 channel version. The only objective in adding the sub is to increase system dynamic range and reduce bass distortion below 30-40hz.

 

Assume I cross my mono sub over at 40hz. Assume also that the sub can produce much greater SPLs below 40hz at much lower distortion than my full range speakers can. Wouldn't DIRAC adjust accordingly when I remeasure with the sub? That is, wouldn't DIRAC's filter with said mono sub reduce some of the subwoofer frequencies played through my R/L channels such that bass distortion can be reduced R/L at those lowest frequencies and DR increased?

 

Michael.

[wgscott]

I have my (Rel) sub hooked up with speaker-level inputs, and Dirac handles that ok, with no crossover. I would think a crossover would simplify the problem Dirac has to solve.

[dallasjustice]

Thanks. Where do you cross the sub over?

 

Would you say the addition of the sub makes your R/L work less hard at those subwoofer frequencies so that you have better DR? I used to own cm9s and I don't remember subwoofer frequencies coming out of my speakers at that time. It seems logical to me that a sub would help reduce distortion using DIRAC.

 

I have an RME card I could use for multi-channel but the complications of multi-channel are too great in my system.

[wgscott]

Sub is crossed over at about 80Hz. The speakers aren't crossed over, but tail off around 62 Hz (-3db; a bit higher than the CM9s). I only did the test drive of Dirac, so I by no means mastered it.

[petecare]

Interesting. I'm searching how with my sub 12 (Adam with 2 front Adam A77 X) to set up all... A friend explain how to do crossover.

The sub is really a good sub. HZ below 25 !! And finally I had founded some filtrage with the 2 fronts HP.

Some days ago I have changed my system in other room. Now I don't have patience to change anything....

Crossed, too, near 80 Hz. My new room is better than the other (very bright sound)

So, if any information to set up the 3 ways system with simplicity can bring a better listening, thanks to give infos.

[wgscott]

http://www.computeraudiophile.com/f12-headphones-and-speakers/classical-music-2-channel-and-sub-woofers-8189/

[petecare]

Sorry but I listened all kind of music.

Jazz pop blues and sometimes MAHLER but only In other audio sysrem

[flak]

This is a personal opinion but I'm favourable to subwoofers as long as they are well integrated (which is not always the case)... the reasons are the ones that Michael has explained.

 

Dirac Live can greatly benefit the integration and will adjust accordingly, it can be very effective in the difficult case of a single subwoofer and I have positive feedback from users (i.e. Martin Logans with a single REL).

 

It has anyhow to be taken into account that Dirac Live Stereo is not a crossovering solution so that some kind of crossovering (passive or active) should be present downstream.

 

Flavio

[dallasjustice]

Thanks guys. I think it's best to get my system crossed over. I can do that in my DAC. I just need to send it back to Vincent to get that feature. Nyal also said it would be possible to use the ELF on JLaudio subs and just set a crossover in jriver or dirac. I like the more traditional approach. Of course, Yoav thinks I should get another get pair of woofers to make my speakers the professional version. :-) That would be awesome but I think I am too nearfield for that. My ear is 8'8" to each tweeter. I doubt the speaker could have enough forward rake to make it really worthwhile.

[dallasjustice]

Flavio,

I am planning on testing an external crossover in a 2 mono sub arrangement. My setup will require 10-14ms of delay. Once the subs are dialed correctly, I will run a 2CH DIRAC sweep. Would this delay cause any problems taking a good measurement in DLCT?

 

This is a personal opinion but I'm favourable to subwoofers as long as they are well integrated (which is not always the case)... the reasons are the ones that Michael has explained.

 

Dirac Live can greatly benefit the integration and will adjust accordingly, it can be very effective in the difficult case of a single subwoofer and I have positive feedback from users (i.e. Martin Logans with a single REL).

 

It has anyhow to be taken into account that Dirac Live Stereo is not a crossovering solution so that some kind of crossovering (passive or active) should be present downstream.

 

Flavio

[mayhem13]

It's important to consider the LF response and alignment type when determining not only the crossover point but the desired reduction in distortion. Of course playback level is a factor as well. The slope of the crossover and how it overlaps your mains natural rolloff can result in either near perfect phase alignment....or a cancellation mess....which is usually the case with ported mains which have two impedance peaks, one for the Fs of the driver and another for the tuned system frequency.

 

It's been my experience that sealed systems are much easier to integrate and overall produce better results with open back/dipole being the ultimate but who's got the room for 15" woofers in their mains!

 

Now with your crossover point of 40hz, using a ported subwoofer is almost pointless in most cases unless the sub is a monster with a very low tuning frequency. These systems are usually 3-4 cuft or better with long port lengths. Remember if a sub mfgr specs an F3 of 30hz, the rolloff is 18db per octave or 3rd order.....falling fast. But that doesn't take room gain into account. Most closed rooms begin to add gain in the 50hz range and can be as much as 10-12 db or more by the time 20hz rolls around. You can't hear it, but you can certainly feel it.

[dallasjustice]

Thanks Mayhem! My speakers are sealed.

 

I know that I could try this myself and I'm sure that I would eventually figure it out. However, I will have Nyal Mellor assisting me with the sub integration. I plan on trying out his DEQX HDP-4 unit the first time I do this. I don't know if I will end up keeping the DEQX are trying another MCH DAC later on. I've heard good things about the DEQX though. We will see. I know that Nyal is certified in Subversive Subwoofer Sorcery, so I think I have a good shot at getting it right.

 

I'll have one JL F113 on the frontwall at about 75% width and the another JL Audio F113 on the backwall at about 25% width. Nyal and I have worked together for a couple of years. We've got my room pretty well mapped out so it should go pretty smooth. I just need to get the impulse response perfect on the subs first. Once that happens, I know the DIRAC 2CH will take care of the rest. I'm very excited about this experiment. I think it will work. My room has very well controlled bass. However, there are a few of the length/axial modes/nulls that room treatments can't do much more for. That's the main purpose for the 2 subs. However, I anticipate that the subs will dramatically increase the DR, LF speed and overall kick-some-ass factor in my room. Wish me luck. I'll report back later on. :-)

 

Michael.

 

It's important to consider the LF response and alignment type when determining not only the crossover point but the desired reduction in distortion. Of course playback level is a factor as well. The slope of the crossover and how it overlaps your mains natural rolloff can result in either near perfect phase alignment....or a cancellation mess....which is usually the case with ported mains which have two impedance peaks, one for the Fs of the driver and another for the tuned system frequency.

 

It's been my experience that sealed systems are much easier to integrate and overall produce better results with open back/dipole being the ultimate but who's got the room for 15" woofers in their mains!

 

Now with your crossover point of 40hz, using a ported subwoofer is almost pointless in most cases unless the sub is a monster with a very low tuning frequency. These systems are usually 3-4 cuft or better with long port lengths. Remember if a sub mfgr specs an F3 of 30hz, the rolloff is 18db per octave or 3rd order.....falling fast. But that doesn't take room gain into account. Most closed rooms begin to add gain in the 50hz range and can be as much as 10-12 db or more by the time 20hz rolls around. You can't hear it, but you can certainly feel it.

[mayhem13]

Add another 113 on a side wall and all your modes will vanish like clock jitter in an Ayre DAC!

[dallasjustice]

Add another 113 on a side wall and all your modes will vanish like clock jitter in an Ayre DAC!

The only timing errors that matter to an audiophile are measured in femtoseconds not milliseconds. You of all people should know that. :-)

[dallasjustice]

DIRAC + DEQX=awesome!

[Selarom]

Hello All!

 

Just found this topic...

 

I wonder if the same can happen using the analog crossover feature on the Emotiva XSP-1. Plan is I get my LH Labs Pulse Infinity DAC. Go from there to XSP-1 and do analog crossover to subs at 80hz or whatever to two subs using the summed subwoofer output so both subs play the same frequencies helping me with room modes and bass evenness in the room.

 

XSP-1 gen2 is just $799 now

 

My worry is delay time between speakers and subs.. Could DIRAC 2ch correct for that? It will see the whole thing as just two speakers...

 

what do you think?

[Fitzcaraldo215]

Hello All!

 

Just found this topic...

 

I wonder if the same can happen using the analog crossover feature on the Emotiva XSP-1. Plan is I get my LH Labs Pulse Infinity DAC. Go from there to XSP-1 and do analog crossover to subs at 80hz or whatever to two subs using the summed subwoofer output so both subs play the same frequencies helping me with room modes and bass evenness in the room.

 

XSP-1 gen2 is just $799 now

 

My worry is delay time between speakers and subs.. Could DIRAC 2ch correct for that? It will see the whole thing as just two speakers...

 

what do you think?

 

I use the Mch version of Dirac, and I highly recommend it. Dirac 2ch cannot do proper timing correction for the sub, directly at least. The sub is not a separate channel - that would be 3 channels - and I do not think the 2ch version has any channel distance or level settings, unlike the Mch version. Indirectly via its time domain filter logic, it is also highly doubtful. If the sub has a variable phase control, there might be a long shot possibility to get everything in synch. But, don't count on it even with a lot of work. Sorry.

 

Don't know the XSP-1 gen 2, but could it accept HDMI directly from the computer? Then it could do digital bass management, which is often better than analog. That would leave out your DAC in favor of the Emotiva's, of course.

[Selarom]

I use the Mch version of Dirac, and I highly recommend it. Dirac 2ch cannot do proper timing correction for the sub, directly at least. The sub is not a separate channel - that would be 3 channels - and I do not think the 2ch version has any channel distance or level settings, unlike the Mch version. Indirectly via its time domain filter logic, it is also highly doubtful. If the sub has a variable phase control, there might be a long shot possibility to get everything in synch. But, don't count on it even with a lot of work. Sorry.

 

Don't know the XSP-1 gen 2, but could it accept HDMI directly from the computer? Then it could do digital bass management, which is often better than analog. That would leave out your DAC in favor of the Emotiva's, of course.

 

Thanks for the reply! I supposed so but thought maybe it could work. I would need then a mch DAC for it to work best or even use my AV receiver then through hdmi. But I wouldn't be able to integrate my DAC as planned.

 

My Pulse Infinity, like many DACs is strictly a 2 ch DAC. The XSP-1 is an analog preamp. No DSP or DAC inside. It does have an analog crossover circuit and can output to subs in stereo mode and there is a mono output as well.

[flak]

 

My worry is delay time between speakers and subs.. Could DIRAC 2ch correct for that? It will see the whole thing as just two speakers...

 

 

That's correct, if the crossovering is downstream (after Dirac Live) DIRAC 2ch (Stereo) will treat the speakers and subs as one... and it will align in time those regions of frequencies that require it as if the sub was just another driver of the main speakers.

 

Flavio

[tne]

^ in my case I have a 2.1 system (listed in my sig and described in other Dirac thread) with stereo Dirac.

source -> DAC -> sub -> mid-woofer/tweeter. the sub has a HF cutoff at ~80Hz and the signal to the mid-woofer/tweeter systems is high pass filtered at 85 Hz.

 

the bass improvements are significant, but perhaps two subs, each paired with a mid-woofer/tweeter would be even better from the standpoint of Dirac implementation. Flavio, your thoughts? If I traded my Sub10 for two Sub8's, for example.

[Selarom]

That's correct, if the crossovering is downstream (after Dirac Live) DIRAC 2ch (Stereo) will treat the speakers and subs as one... and it will align in time those regions of frequencies that require it as if the sub was just another driver of the main speakers.

 

Flavio

 

Awesome! Thank you Flavio! I feel more confident about it now! Thanks again!