Using Multi Subs & MSO To Get Even Bass In Room & Across Sitting Positions

[Snoopy8]

10 hours ago, Satanica said:

You can have seperate PEQ's, gains, delays etc outside of Dirac that can be set in the SHD although I don't know if you can import those settings into the SHD series from REW or MSO.

I assume you can import them into the Beringher 2496 (which you have and are doing) or potentially other miniDSP units and one would need one of these or equivalent anyway for D/A conversion and long delays for the subwoofer(s) if required.

MSO can export the filters to any miniDSP

https://www.andyc.diy-audio-engineering.org/mso/html/tut_main_13.html#biquad_info

But I have to enter manually  Fortunately, I can enter the values quickly in a Behringer Windows app and do a file transfer.

 

11 hours ago, Satanica said:

Well as per above if you measured with REW and then ran MSO and then exported and imported into a Behringer or miniDSP or eqivalent unit and then ran Dirac over the Left and Right Speakers with subwoofer(s) on and working with them I can't see right now at least why not.

OK, let's give this a go.  I will make you the same offer I made previously.   If you do the measurements, I will do a Subs only MSO run and give you the MSO file.  This will make your learning a bit easier and get things going quicker.

 

To measure, follow this process (and I assume you know REW).  You will need to use one of the main speakers for the timing reference.

https://www.andyc.diy-audio-engineering.org/mso/html/measuring.html

 

Assuming you have 2 subs (SubL, SubR), you will need 3 measurements for each of the subs, one at the main listening position (MLP) and one each on either side, about 0.5m away; lets call them LP, RP.  So, in REW, there should be 6 measurements, MLP SubL, MLP SubR, LP SubL, LP SubR, RP SubL, RP SubR.  PM your REW file and I will send back the MSO files.  You can then export the filters to your miniDSP and rerun Dirac Live. 

[davewantsmoore]

On 28/02/2018 at 3:16 PM, Snoopy8 said:

Was (and still am) no bass head, but understood why so many pursue this!

 

The shorter the sound, the more high frequencies and the more low frequencies it has in it.

 

Probably not what most people think.

 

Everyone need subwoofers  

 

[davewantsmoore]

18 hours ago, Snoopy8 said:

Can the SHD Studio do both Dirac Live and apply MSO filters at the same time? 

** Also, can Dirac Live measure the subs with MSO filters applied?

 

Yes

[Satanica]

4 hours ago, Snoopy8 said:

MSO can export the filters to any miniDSP

https://www.andyc.diy-audio-engineering.org/mso/html/tut_main_13.html#biquad_info

But I have to enter manually  Fortunately, I can enter the values quickly in a Behringer Windows app and do a file transfer.

 

OK, let's give this a go.  I will make you the same offer I made previously.   If you do the measurements, I will do a Subs only MSO run and give you the MSO file.  This will make your learning a bit easier and get things going quicker.

 

To measure, follow this process (and I assume you know REW).  You will need to use one of the main speakers for the timing reference.

https://www.andyc.diy-audio-engineering.org/mso/html/measuring.html

 

Assuming you have 2 subs (SubL, SubR), you will need 3 measurements for each of the subs, one at the main listening position (MLP) and one each on either side, about 0.5m away; lets call them LP, RP.  So, in REW, there should be 6 measurements, MLP SubL, MLP SubR, LP SubL, LP SubR, RP SubL, RP SubR.  PM your REW file and I will send back the MSO files.  You can then export the filters to your miniDSP and rerun Dirac Live. 

 

Thanks again for the offer. If I am already using Dirac what benefit would I be getting? 

 

My subs are front and back.

 

On another note regarding the Geddes approach I wonder whether my mono subwoofers would be audibly localised if they were run up to 200Hz. I also wonder if corner loaded subwoofers have longer decay times. 

Edited April 2, 2021 by Satanica

[davewantsmoore]

15 minutes ago, Satanica said:

If I am already using Dirac what benefit would I be getting? 

EQ applied to each bass source independently.

 

16 minutes ago, Satanica said:

On another note regarding the Geddes approach I wonder whether my mono subwoofers would be audibly localised if they were run up to 200Hz.

 

Yes.

You should EQ your subwoofer to have flat from response from 0 to 200Hz.... but then place a low pass filter ~ an octave lower.

 

 

16 minutes ago, Satanica said:

 I also wonder if corner loaded subwoofers have longer decay times. 

 

At low frequencies there really aren't "corners".    Everything is quite close to the corner (measured in wavelengths), and at very low frequencies, to every corner of the room.

 

In short, no.

 

[Snoopy8]

15 minutes ago, Satanica said:

 

Thanks again for the offer. If I am already using Dirac what benefit would I be getting? 

 

My subs are front and back.

 

On another note regarding the Geddes approach I wonder whether my mono subwoofers would be audibly localised if they were run up to 200Hz. I also wonder if corner loaded subwoofers have longer decay times. 

I run MSO to integrate my subs so that Dirac will see them as one big sub.

 

I have not tried front and back, not allowed in family room!  If done correctly, there would be no localising but may need to tweak if so.

 

One of the challenges with using MSO is to drop conventional thinking about various filters. This will surprise many people that MSO is setting the cross overs at 180 Hz, not 80!!!  Similarly, with delays, MSO calculates its own.

 

Offer remains open if you want to try MSO anytime...

[Satanica]

On 02/04/2021 at 4:00 PM, davewantsmoore said:

EQ applied to each bass source independently.

 

I can do that now by simply applying PEQ's in one of my two miniDSP's.

I don't need MSO to do that but seemingly it would do a good job.

 

On 02/04/2021 at 4:00 PM, davewantsmoore said:

You should EQ your subwoofer to have flat from response from 0 to 200Hz.... but then place a low pass filter ~ an octave lower.

 

I have two subwoofers not one. As you would know by placing them far from each other (in my case midwall front and back) they have the chance to "passively EQ" each other i.e. where one has a dip the other doesn't. If I was to actively EQ each one of them to both flat wouldn't that make each one work harder to fill in gaps? My understanding is YES.

 

On another note I believe @Snoopy8 has used his subwoofers to EQ all the way up to 200Hz with no low pass filter applied (typically 80Hz or lower at 24dB\octave). I don't know why Snoop you have them working so high. Well I assume it is to get better bass up to 200Hz but I think this would make your subwoofers localised. Also, running a subwoofer(s) with the KII THREE's higher than 50Hz aren't you effectively removing some of their cardioid advantage? I suggested you potentially use a Dirac based device to EQ more than just the frequencies covered by low passed subwoofers. I presumed at the time you were using a typical low pass filter but only to learn that you are not. But anyway I'll leave you to it and will cease repeating the suggestion.

 

On 02/04/2021 at 4:00 PM, davewantsmoore said:

At low frequencies there really aren't "corners".    Everything is quite close to the corner (measured in wavelengths), and at very low frequencies, to every corner of the room.

 

In short, no.

 

I'm not educated to know or calculate but surely it depends on the frequencies covered by the subwoofer(s)? How low is low? They are low pass filtered at 80Hz\24dB.

Edited April 4, 2021 by Satanica

[Satanica]

On 02/04/2021 at 4:03 PM, Snoopy8 said:

One of the challenges with using MSO is to drop conventional thinking about various filters. This will surprise many people that MSO is setting the cross overs at 180 Hz, not 80!!!  Similarly, with delays, MSO calculates its own.

 

I don't think this is correct as this implies it is limited to a particular optimisation strategy, it is not. Remember the documentation mentions numerous optimsation strategies. MSO really makes no recommendation at what the crossover should be or if there should be one. MSO is a general purpose tool to automatically optimise subwoofers and bass frequencies within a desired frequency range and then you can choose to apply a crossover or not. If one was to use stereo subwoofers then one could potentially run them much higher than the typical omni-directional mono subwoofer crossover (less than 80Hz) and not risk localisation issues. EDIT: I just remembered that MSO only works on mono subwoofers.

Edited April 4, 2021 by Satanica

[Snoopy8]

@Satanica

 

If I had done things wrong in MSO, it would have showed up in the measurements of the actual results and also in the listening tests. For example, I can hear the subs if I do silly things in the MSO setup.  I can only share with you what I know in using it, not the theory.

 

If you want a theoretical debate on what MSO is supposed to be doing, suggest joining the discussion thread on 

http://www.avsforum.com/forum/113-subwoofers-bass-transducers/2103074-optimizing-subwoofers-integration-mains-multi-sub-optimizer.html

The author AndyC and plenty of others can provide you with the details you desire...

[davewantsmoore]

4 hours ago, Satanica said:

I can do that now by simply applying PEQ's in one of my two miniDSP's.

I don't need MSO to do that but seemingly it would do a good job.

 

Sure.... MSO will just tell you what EQ to apply.

 

4 hours ago, Satanica said:

If I was to actively EQ each one of them to both flat wouldn't that make each one work harder to fill in gaps? My understanding is YES.

 

This isn't what MSO does.

 

 

 

4 hours ago, Satanica said:

On another note I believe @Snoopy8 has used his subwoofers to EQ all the way up to 200Hz with no low pass filter applied (typically 80Hz or lower at 24dB\octave).

 

I'd be surprised if he had no LPF..... but you could do that, but you'd need them arranged symmetrically so as not to skew the stereo/image.

 

4 hours ago, Satanica said:

I'm not educated to know or calculate but surely it depends on the frequencies covered by the subwoofer(s)? How low is low? They are low pass filtered at 80Hz\24dB.

 

I was only thinking about 0 to 80.

 

80Hz is ~4m long.

 

So in a (large) 8m x 8m room....a  subwoofer in the corner of the room is only 1 wavelength distance (ie. delay) from a subwoofer in the centre of the room..

 

For 20Hz, this is one-quarter of a wavelength.

[WasM]

@Snoopy8 I've had a few instances where MSO calculated delays are quite substantial, larger than I can input into the AVR for each sub.

Have you had any experience with this?

[Snoopy8]

14 minutes ago, WasM said:

@Snoopy8 I've had a few instances where MSO calculated delays are quite substantial, larger than I can input into the AVR for each sub.

Have you had any experience with this

 My DSP can handle large delays.!

 

You need to change  the max value of the delays in MSO to match your AVR and let it recalculate.  

[WasM]

7 minutes ago, Snoopy8 said:

 You need to change  the max value of the delays in MSO to match your AVR and let it recalculate.  

Do you re-run the optimisation again from 'fresh' or do you make changes (add max delay) on the 'solution' then continue the optimisation?

I hope my query makes sense.

[Snoopy8]

8 minutes ago, WasM said:

Do you re-run the optimisation again from 'fresh' or do you make changes (add max delay) on the 'solution' then continue the optimisation?

I hope my query makes sense.

I have had strange results a few times when I made many, manychanges and had to restart. But generally it should be ok to tweak filters, add and delete.

[Snoopy8]

3 hours ago, WasM said:

Do you re-run the optimisation again from 'fresh' or do you make changes (add max delay) on the 'solution' then continue the optimisation?

I hope my query makes sense.

Are you using clone configurations?  You can do MSO optmisation run, save it, then clone it and try something different.  That way you can always go back to previous runs.

[WasM]

3 minutes ago, Snoopy8 said:

Are you using clone configurations?  You can do MSO optmisation run, save it, then clone it and try something different.  That way you can always go back to previous runs.

Yea might give that a go and see where the 'fresh' vs 'semi optimised' ends up. I'm doing it across 8 seats so gets messy.

 

I might try another config for MLP only. 

 

I'm due for a re-measure of all the seats and subs as the room has had more things put in and I've put one of three port plugs into the sub. Need a few more Easter weekends.....

[Satanica]

On 04/04/2021 at 9:06 PM, davewantsmoore said:

This isn't what MSO does.

 

Yes, that was my understanding too so I must have not understood you.

MSO will find what it thinks is the best combination of EQ between multiple subwoofers.

 

On 04/04/2021 at 9:06 PM, davewantsmoore said:

I was only thinking about 0 to 80.

 

80Hz is ~4m long.

 

So in a (large) 8m x 8m room....a  subwoofer in the corner of the room is only 1 wavelength distance (ie. delay) from a subwoofer in the centre of the room..

 

For 20Hz, this is one-quarter of a wavelength.

 

So for my room that is 7M X 5M with the sub-woofers at the short wall makes them about 2.5M from the closest corner.

 

80Hz 4.32M Wavelength 1.08M Quarter Wavelength

70Hz 4.94M Wavelength 1.24M Quarter Wavelength

60Hz 5.70M Wavelength 1.43M Quarter Wavelength

50Hz 6.88M Wavelength 1.72M Quarter Wavelength

40Hz 8.63M Wavelength 2.16M Quarter Wavelength

 

I have two bass traps in two of the corners although unsure how effective they are.

Placing the subs midwall was based on a hunch from the Harman article that I presume you're aware of:

https://www.harman.com/documents/multsubs_0.pdf

 

Based on the above would there not be some advantage to midwall placement over corner loaded placement?

I think I can understand there are probably pros and cons.

I know I could experiment and measure different subwoofer positions but I just wanted something good overall.

Also front and back midwall on the shortwalls works well in my room and aesthetics and convenience are somewhat important too.

 

Edited April 6, 2021 by Satanica

[davewantsmoore]

4 hours ago, Satanica said:

Based on the above would there not be some advantage to midwall placement over corner loaded placement?

 

Each specific situation is very specifc.

 

I wouldn't over think it though.   I think (ala geddes, etc.) that asymetrical placement, and a higher number of sources, is the most important.

 

The short ansswer is ..... you want to experiment locations for each (un-EQed) woofer, that optimise the response flatness of all woofers.  (eg. locations where one is filling in the dips or peaks of another).   This isn't usually some symetrical layout that you see in a paper/book.

 

That is assuming that we don't want to run them above ~80Hz.

 

It's complicated is the long answer.

[Snoopy8]

On 04/04/2021 at 4:25 PM, Satanica said:

On another note I believe @Snoopy8 has used his subwoofers to EQ all the way up to 200Hz with no low pass filter applied (typically 80Hz or lower at 24dB\octave). I don't know why Snoop you have them working so high.

I am using a low pass filter; otherwise, sound from the subs will bleed into the mains. 

 

MSO allows you to decide what frequency range to optimise and what frequencies to apply the various PEQs.  It depends on the problem you are trying to solve. I know that there are no problems with my implementation of MSO, with actual measurements a good match for MSO curve.  But the important thing is does the system sound good?  Is the bass to taste?  And are the subs integrated?  With the Kii Three so revealing, any issue with the subs integration shows up quickly.

 

On 04/04/2021 at 4:34 PM, Satanica said:

 

I don't think this is correct as this implies it is limited to a particular optimisation strategy, it is not. Remember the documentation mentions numerous optimsation strategies. MSO really makes no recommendation at what the crossover should be or if there should be one. MSO is a general purpose tool to automatically optimise subwoofers and bass frequencies within a desired frequency range and then you can choose to apply a crossover or not. If one was to use stereo subwoofers then one could potentially run them much higher than the typical omni-directional mono subwoofer crossover (less than 80Hz) and not risk localisation issues. EDIT: I just remembered that MSO only works on mono subwoofers.

Agree, MSO is only a tool.  It has 3 optimisation options. The tutorial intro discusses various optimisation strategies and what MSO does.

 

19 hours ago, davewantsmoore said:

The short ansswer is ..... you want to experiment locations for each (un-EQed) woofer, that optimise the response flatness of all woofers.  (eg. locations where one is filling in the dips or peaks of another).   This isn't usually some symetrical layout that you see in a paper/book.

Agree, more subs in asymmetrical layouts  can lead to better results.  But sadly, am WAF constrained, so MSO has been useful.

[Satanica]

10 minutes ago, Snoopy8 said:

I am using a low pass filter; otherwise, sound from the subs will bleed into the mains. 

 

MSO allows you to decide what frequency range to optimise and what frequencies to apply the various PEQs.  It depends on the problem you are trying to solve. I know that there are no problems with my implementation of MSO, with actual measurements a good match for MSO curve.  But the important thing is does the system sound good?  Is the bass to taste?  And are the subs integrated?  With the Kii Three so revealing, any issue with the subs integration shows up quickly.

 

I might be wrong or confused but I don't think you have a low pass filter applied to your subwoofers.

Unless I'm mistaken where "MSO allows you to decide what frequency range to optimise and what frequencies to apply the various PEQs" simply dictates the  correction range that is applied to them.

Perhaps @davewantsmoore can chime in.

Edited April 7, 2021 by Satanica

[Snoopy8]

1 minute ago, Satanica said:

I might be wrong or confused but I don't think you do have a low pass filter.

Currently running this MSO config. 

 

2 minutes ago, Satanica said:

Unless I'm mistaken where "MSO allows you to decide what frequency range to optimise and what frequencies to apply the various PEQs" simply dictates its correction range.

Can you point me to the documentation which says this. 

 

You can choose not to use LPF within MSO, add it manually in DSP.  Or you can add LPF, set it manually and exclude from optimisation.  Or add a LPF and let MSO optimise.

 

 

[Satanica]

2 minutes ago, Snoopy8 said:

Currently running this MSO config.

 

Great, what is the frequency?

Lets say it is 80Hz and if so then how is EQ being applied all the way up 200Hz without EQ applied to your mains?

Unless I'm mistaken you've stated your Mains are not being EQ'd, correct?

[Satanica]

11 minutes ago, Snoopy8 said:

Can you point me to the documentation which says this. 

 

You can choose not to use LPF within MSO, add it manually in DSP.  Or you can add LPF, set it manually and exclude from optimisation.  Or add a LPF and let MSO optimise.

 

OK, it appears to me now that I had that part wrong but the above questions still apply.

Edited April 7, 2021 by Satanica

[Snoopy8]

21 minutes ago, Satanica said:

Great, what is the frequency?

Lets say it is 80Hz and if so then how is EQ being applied all the way up 200Hz without EQ applied to your mains?

Unless I'm mistaken you've stated your Mains are not being EQ'd, correct?

Currently choosing to use 130 Hz, solving issue below that.  MSO has freedom to go below. And PEQS are applied below that.  I am actively listening for sub integration problems and I am measuring the results.

 

If you are more comfortable with using 80 Hz, then use that; MSO can only solve issues below 80 Hz. 

[Satanica]

39 minutes ago, Snoopy8 said:

Currently choosing to use 130 Hz, solving issue below that.  MSO has freedom to go below. And PEQS are applied below that.  I am actively listening for sub integration problems and I am measuring the results.

 

If you are more comfortable with using 80 Hz, then use that; MSO can only solve issues below 80 Hz. 

 

Righto, is that both subs or just the L (Left)?

Is MSO choosing or was that you?

 

So at 130Hz at 24dB\Octave the subwoofers will already be 6b down.

I don't have something to simulate with in front of me but I don't think you'll have much EQ potential above 125Hz and of course won't be able to EQ the Left and Right channels independently.

 

At the moment I think you'll have little to no EQ applied above about 125Hz and will have two mono subwoofers that are being crossed over at frequencies far higher than is typical.
You might not have noticeable localisation issues if your two subwoofers are somewhat symmetrically laid out as that would place those frequencies centre between them anyway rather than to one side, I think.

I have to mention again I think some of the KII THREE cardioid will be overridden by the subwoofers working higher than 50Hz.

From memory @gibbo9000 has his subwoofer low passed and hi KII THREE's high passed at 50Hz.

In my case yes I would not feel comfortable with my subwoofers crossed over any higher than 80Hz; I think it would be a bit overkill anyway as my mains have two 10inch drivers each.

 

It seems like MSO could also EQ your mains and therefore you could be getting EQ higher up in frequency range but of course as discussed you'd need to forego DSD.

Like many things in audio its all about compromises and obviously DSD is high on your list.

Edited April 7, 2021 by Satanica