Multi-Sub Optimizer (MSO): Lessons Learned, Tips & Tricks

[PaulF2020]

If you haven't done so, have a look at the MSO 2.0 tutorial video linked in my sig below.

Yes, I've watched your and videos from other people on the subject. I just re-watched it again. Thank you very much for great video!

If you are only looking to time align the subs using MSO, the just use the "Maximize SPL using only delays and all-pass filters" Optimization Type, setting the delay range to the max range you have available in your AVR and not using the All-pass filter option.

Yes, that part makes sense, thank you. I have delay in cm, so maximum is 999cm which is around 29ms.

For sub gain settings, set them at a high setting (say 80% to 100% of max) on rotary dials on the subs themselves prior to doing your raw measurements and leave them at these settings permanently (it's handy to mark the setting on a piece of masking tape beside the dial in case you accidentally change them later) and AVR volume such that your raw measurement sweeps have max peaks of around 90-100dB SPL in the 30-60Hz range. This is a decent sweet spot between testing subs near but not approaching their upper limit and well above the noise floor.

Thanks for this, I was really puzzled on what is the best way to approach it.

Use the AVR amp sub gain setting after MSO to balance the subs and the mains but do not adjust the rotary dials on the subs.

So I have few of questions here:
1. How do I match levels correctly to mains? Just using SPL? Or running a full sweep in REW and adjusting gain equally on both? Or there is a better way?
2. Your video explains how to match subs between each other, but what is the best way to match delay to mains? There will be sub amplifier delay, even on a wired sub, delay can might be significant.
3. Is there a way to find best crossover point in MSO?

You can optionally use the "Shared Filters" in MSO for the 8 PEQ spots you have in the Lyngdorf as long as the room perfect correction does not override these during its processing.

Thanks, yes i spoke to Lyngdorf and they say they do not override PEQs which are set manually.

 

[PaulF2020]

Guys, How can I do phase view in latest MSO version? It looks like graph options windows is completely different.

 

[andyc56]

Guys, How can I do phase view in latest MSO version? It looks like graph options windows is completely different.

Navigate to "Axes", and select a combination of axis assignments that contains phase per the image below.

If you want to show only magnitude or only phase for some traces, select the trace you want to modify and check or uncheck the checkboxes shown.

The new Graph Properties dialog combines the old Graph Properties dialog with the old Trace Properties dialog so you can do everything with graphs and traces without having to always switch back and forth between dialogs. As you add and remove traces, they will appear under or disappear from the Trace Properties node of the tree, which allows you to select the trace to make whatever modifications to it you wish.

For detailed help on the page you're working on, make sure a control on that page is selected (not the tree on the left) and either press the Help button or F1.

 

[PaulF2020]

Navigate to "Axes", and select a combination of axis assignments that contains phase per the image below.


The new Graph Properties dialog combines the old Graph Properties dialog with the old Trace Properties dialog so you can do everything with graphs and traces without having to always switch back and forth between dialogs. As you add and remove traces, they will appear under or disappear from the Trace Properties node of the tree, which allows you to select the trace to make whatever modifications to it you wish.

For detailed help on the page you're working on, make sure a control on that page is selected (not the tree on the left) and either press the Help button or F

Thank you, I saw that option, but I can't understand how to overlay it without causing this:

I'd like to overlay like in the video:

 

[andyc56]

Thank you, I saw that option, but I can't understand how to overlay it without causing this:
View attachment 481452

You have the phase on the left and the magnitude on the right, which is fine, but not the usual way. Your right axis of magnitude is configured for limits of 0+/-180 as if it were phase, while your phase axis is configured as if it were magnitude, with a lower limit of 60 and an upper limit of 114, which doesn't show the full phase range.

To make your graphs look like the ones in Dave's video, set them for magnitude on the left and phase on the right. Configure both the left and right axes for manual scaling, and specify limits to be similar to what Dave has in his video.

When you change axis assignments, the axis limits "stick" to the quantity being plotted, not the axis itself. So if you decide to swap which quantity is on the left and right, the limits will follow the quantity being plotted (magnitude or phase) as you swap them. In your case, you have limits for magnitude and phase interchanged, so you need to fix that first.

Also, the phase of the response at each position is not meaningful and not what Dave is plotting in his video. It looks like you may have misunderstood that part of the video.

Edit: As you change axis properties, it can help to drag the rather large Graph Properties dialog to the side so you can see the graph. Changes are applied by clicking the Apply button or switching to another property page. Mods to trace properties show up immediately without needing to press Apply.

 

[PaulF2020]

You have the phase on the left and the magnitude on the right, which is fine, but not the usual way. Your right axis of magnitude is configured for limits of 0+/-180 as if it were phase, while your phase axis is configured as if it were magnitude, with a lower limit of 60 and an upper limit of 114, which doesn't show the full phase range.

To make your graphs look like the ones in Dave's video, set them for magnitude on the left and phase on the right. Configure both the left and right axes for manual scaling, and specify limits to be similar to what Dave has in his video.

When you change axis assignments, the axis limits "stick" to the quantity being plotted, not the axis itself. So if you decide to swap which quantity is on the left and right, the limits will follow the quantity being plotted (magnitude or phase) as you swap them. In your case, you have limits for magnitude and phase interchanged, so you need to fix that first.

Also, the phase of the response at each position is not meaningful and not what Dave is plotting in his video. It looks like you may have misunderstood that part of the video.

Edit: As you change axis properties, it can help to drag the rather large Graph Properties dialog to the side so you can see the graph. Changes are applied by clicking the Apply button or switching to another property page. Mods to trace properties show up immediately without needing to press Apply.

Oh, stupid me, I was looking in a wrong place. I got it right now, thank you very much.

 

[PaulF2020]

If you are only looking to time align the subs using MSO, the just use the "Maximize SPL using only delays and all-pass filters" Optimization Type, setting the delay range to the max range you have available in your AVR and not using the All-pass filter option.

Ok, tried different sub placements and got some Okayish measurements. However, when I run Maxspl it is aligning listening positions better, but creates a huge dip around 68Hz.
Before:

After:

 

[terfenol-D]

Also, be aware that SPL maximization only works in MSO for sub-only configurations, so if you're using it to integrate subs and mains, that would unfortunately be a two-stage process. Over the years, usage of subs+mains configurations has dwindled to almost nothing, so there has been almost no development in that area.

I think this answers my question but wanted to confirm - is MSO really only used for multiple subs (2+) using LFE channel?

Does it require a minidsp like device to integrate the subs? I have two SVS subs I wanted to integrate with my mains using Lyngorf room perfect. It has two options - using LFE (2.1) or using two main plus two sub (2.2). Room perfect instructions/videos recommend using 2.2 setup. I was thinking of using MSO with the built in limited dsp of the svs subs to position and iintegrate the subs as best as possible prior to using . It sounds like this is not really an option.

 

[andyc56]

I think this answers my question but wanted to confirm - is MSO really only used for multiple subs (2+) using LFE channel?

Does it require a minidsp like device to integrate the subs? I have two SVS subs I wanted to integrate with my mains using Lyngorf room perfect. It has two options - using LFE (2.1) or using two main plus two sub (2.2). Room perfect instructions/videos recommend using 2.2 setup. I was thinking of using MSO with the built in limited dsp of the svs subs to position and iintegrate the subs as best as possible prior to using . It sounds like this is not really an option.

The MSO homepage describes the hardware requirements.

 

[terfenol-D]

The MSO homepage describes the hardware requirements.

Thank you - I read so much of this thread I forgot to look at the actual website.

I still have my question though - can the software help me integrate the subs on its own or is few a better tool for that?

 

[DaveBoswell]

Thank you - I read so much of this thread I forgot to look at the actual website.

I still have my question though - can the software help me integrate the subs on its own or is few a better tool for that?

Yes. You can use MSO to calculate the PEQ to use within the SVS subs. You won’t get precisely accurate results as the granularity of settings with the subs is not that high and you’ll have to do a bit of a calc to convert the MSO Q to the subs Q (from memory here is I played around with this approach some years back when doing some experimenting). Just use the output PEQ options in MSO and no shared PEQ or any delays or gain settings.

This will provide a rough and probably pretty decent starting place for you prior to running the AVR optimization.

 

[PaulF2020]

I think this answers my question but wanted to confirm - is MSO really only used for multiple subs (2+) using LFE channel?

Does it require a minidsp like device to integrate the subs? I have two SVS subs I wanted to integrate with my mains using Lyngorf room perfect. It has two options - using LFE (2.1) or using two main plus two sub (2.2). Room perfect instructions/videos recommend using 2.2 setup. I was thinking of using MSO with the built in limited dsp of the svs subs to position and iintegrate the subs as best as possible prior to using . It sounds like this is not really an option.

If you're going to run RP, I wouldn't do EQ at all, just correct delays, phase and high/low pass filters. Tbh, I'm still puzzled on how to use MSO for sub+mains integration. Minidsp has FAQ on 2.2 systems, but it is not really detailed enough.

 

[Dure16]

If you haven't done so, have a look at the MSO 2.0 tutorial video linked in my sig below. If you are only looking to time align the subs using MSO, the just use the "Maximize SPL using only delays and all-pass filters" Optimization Type, setting the delay range to the max range you have available in your AVR and not using the All-pass filter option.

For sub gain settings, set them at a high setting (say 80% to 100% of max) on rotary dials on the subs themselves prior to doing your raw measurements and leave them at these settings permanently (it's handy to mark the setting on a piece of masking tape beside the dial in case you accidentally change them later) and AVR volume such that your raw measurement sweeps have max peaks of around 90-100dB SPL in the 30-60Hz range. This is a decent sweet spot between testing subs near but not approaching their upper limit and well above the noise floor.

Use the AVR amp sub gain setting after MSO to balance the subs and the mains but do not adjust the rotary dials on the subs.

You can optionally use the "Shared Filters" in MSO for the 8 PEQ spots you have in the Lyngdorf as long as the room perfect correction does not override these during its processing.

This is really helpful for taking measurements. Do you leave REW at the default -12db before adjusting AVR volume?

 

[DaveBoswell]

This is really helpful for taking measurements. Do you leave REW at the default -12db before adjusting AVR volume?

Yes I do.

 

[MFA]

Why not DBA if you already decided to sacrifice SPL for better decay?
Just set delay, invert, lock and let MSO optimize with PEQ's?! No AP though

 

[Dure16]

Yes I do.

Thank you. I followed the process you explained above for measurements, ran MSO multi-stage, and limited the shared gain block to +/-5 as mentioned in your tutorial. (Great tutorial by the way)

However, Audyssey still isn’t measuring the subs at sufficient volume. Even raising gain to +12db from within minidsp isn’t high enough for Audyssey.

Any ideas? I’m happy to provide additional details, but am not sure what to include.

 

[DaveBoswell]

Thank you. I followed the process you explained above for measurements, ran MSO multi-stage, and limited the shared gain block to +/-5 as mentioned in your tutorial. (Great tutorial by the way)

However, Audyssey still isn’t measuring the subs at sufficient volume. Even raising gain to +12db from within minidsp isn’t high enough for Audyssey.

Any ideas? I’m happy to provide additional details, but am not sure what to include.

Make sure that you set the gain setting on your subs as high as possible and set MiniDSP sahred gain to 0dB prior to taking your raw measurements. If you don't do this, then you won't give MSO enough "room" to knock down major peaks without the overall sub vol being too low. Another thing I have noticed is that if there is a large discontinuity in response above the upper limit in MSO, it can confuse AVR measurements - check to see if there are large peaks above 200Hz in your post optimization response - if you do see these, then you need to raise your target in MSO.

 

[Dure16]

Make sure that you set the gain setting on your subs as high as possible and set MiniDSP sahred gain to 0dB prior to taking your raw measurements. If you don't do this, then you won't give MSO enough "room" to knock down major peaks without the overall sub vol being too low. Another thing I have noticed is that if there is a large discontinuity in response above the upper limit in MSO, it can confuse AVR measurements - check to see if there are large peaks above 200Hz in your post optimization response - if you do see these, then you need to raise your target in MSO.

Thank you. I have the sub gain/volume dials at 9/10 and will try maxing them out. And I have all the gains in MiniDSP at 0db prior to taking measurements - both input gain and each sub's gain. Is that correct? If yes, is there anything else I can try?

I'm not sure I fully understand the second part of your paragraph, but I don't think I have that problem. Here's my graph (optimized up to 200hz):

 

[PaulF2020]

Make sure that you set the gain setting on your subs as high as possible and set MiniDSP sahred gain to 0dB prior to taking your raw measurements. If you don't do this, then you won't give MSO enough "room" to knock down major peaks without the overall sub vol being too low. Another thing I have noticed is that if there is a large discontinuity in response above the upper limit in MSO, it can confuse AVR measurements - check to see if there are large peaks above 200Hz in your post optimization response - if you do see these, then you need to raise your target in MSO.

I'd be careful with this. In my subs in my room anything over 50% on a gain know will result in massive distortion, will be damaging to subs and over 110dB.

 

[DaveBoswell]

Thank you. I have the sub gain/volume dials at 9/10 and will try maxing them out. And I have all the gains in MiniDSP at 0db prior to taking measurements - both input gain and each sub's gain. Is that correct? If yes, is there anything else I can try?

I'm not sure I fully understand the second part of your paragraph, but I don't think I have that problem. Here's my graph (optimized up to 200hz):


View attachment 488306

This graph looks pretty ok IMO - you could try a target of 90 with shared gain filter limited to plus minus around 2-3 dB to see if helps.

Sounds like maybe you have an AVR/Audyssey settings issue if you are getting level errors with these settings so check the forums for help in this troubleshooting. Also maybe check the sub level setting in your AVR to make sure it is not set at extreme high or low setting - put it at the midpoint of levels. You could also have an issue between your speaker levels and sub levels (can happen with over sensitive or under sensitive speakers, and or with mixing of balanced and unbalanced connections).