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

[Dure16]

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).

Thank you. I’ll try raising that target line.

I don’t think it’s an AVR/Audyssey settings issue, since this is happening during the first step of calibration. No settings come into play for the calibration, as I understand it. Here’s a screenshot of the issue - I can’t get sub volume loud enough to even start Audyssey calibration, even if I increase shared gain +12db in MiniDSP. This was not an issue before MSO.

 

[Dure16]

Thank you. I’ll try raising that target line.

I don’t think it’s an AVR/Audyssey settings issue, since this is happening during the first step of calibration. No settings come into play for the calibration, as I understand it. Here’s a screenshot of the issue - I can’t get sub volume loud enough to even start Audyssey calibration, even if I increase shared gain +12db in MiniDSP. This was not an issue before MSO.


View attachment 488415

Problem fixed! After troubleshooting everything else, I bought a new Audyssey microphone and that solved the problem. The subs measure fine during Audyssey calibration and I can move onto the rest of the setup. The old microphone must have gotten damaged at some point.

I figured I'd share in case anyone else runs into the same issue.

Thanks again for the help.

 

[Dure16]

I’m considering mixing ported and sealed subs and have read that, when doing so, the sealed subs should be high-passed above the ported subs tuning frequency.

1. Do you agree with that logic?
2. Is this done before or after MSO optimization?
3. Anything else to keep in mind when mixing sealed and ported?

 

[andyc56]

I’m considering mixing ported and sealed subs and have read that, when doing so, the sealed subs should be high-passed above the ported subs tuning frequency.

1. Do you agree with that logic?

Definitely not.

2. Is this done before or after MSO optimization?

It should not be done period, either before or after.

3. Anything else to keep in mind when mixing sealed and ported?

There are many things to keep in mind. I could go on for hours, since understanding the "why" involves many details. But I've found over the years that a large percentage of people don't actually care about the "why", and just want to be told what to do. Such people should not be using MSO in the first place, and are the main reason I've mostly stopped forum support of it.

Since you said you are "considering" mixing sealed and ported, this suggests to me that you might not have bought all the subs yet. If you haven't, I'd recommend not mixing them and instead using subs of the same technology having generally similar capabilities, regardless of whether they are sealed or ported.

If you're concerned about a lack of bass extension with sealed subs, I'd suggest reading René's post in this forum about how the zero-order room mode tends to counteract sub LF roll-off, giving more extended LF response than the sub's anechoic behavior would predict. He also has an article in AudioXpress on this topic that's even better than his post here. I highly recommend that article.

If you decide to mix sealed and ported, I can go into detail about the right way to do it in MSO. That's a lengthy explanation, so I'll defer that until I know exactly what you plan to do.

 

[Dure16]

Definitely not.



It should not be done period, either before or after.



There are many things to keep in mind. I could go on for hours, since understanding the "why" involves many details. But I've found over the years that a large percentage of people don't actually care about the "why", and just want to be told what to do. Such people should not be using MSO in the first place, and are the main reason I've mostly stopped forum support of it.

Since you said you are "considering" mixing sealed and ported, this suggests to me that you might not have bought all the subs yet. If you haven't, I'd recommend not mixing them and instead using subs of the same technology having generally similar capabilities, regardless of whether they are sealed or ported.

If you're concerned about a lack of bass extension with sealed subs, I'd suggest reading René's post in this forum about how the zero-order room mode tends to counteract sub LF roll-off, giving more extended LF response than the sub's anechoic behavior would predict. He also has an article in AudioXpress on this topic that's even better than his post here. I highly recommend that article.

If you decide to mix sealed and ported, I can go into detail about the right way to do it in MSO. That's a lengthy explanation, so I'll defer that until I know exactly what you plan to do.

Thank you. While I'm not in the camp of people who don't care about the "why", I will say I am new to this and my technical knowledge is still lacking. I'm trying to learn how all of this works, including potential conflicts and which of those can be addressed via MSO. Thank you for the relevant article to help with my learning.

It sounds like mixing sealed and ported can be quite complicated, may not be worth the trouble, and is likely above my skill level at the moment anyway. I'll plan to stick with one or the other rather than mixing them. I respect and appreciate your guidance here.

 

[DaveBoswell]

Thank you. While I'm not in the camp of people who don't care about the "why", I will say I am new to this and my technical knowledge is still lacking. I'm trying to learn how all of this works, including potential conflicts and which of those can be addressed via MSO. Thank you for the relevant article to help with my learning.

It sounds like mixing sealed and ported can be quite complicated, may not be worth the trouble, and is likely above my skill level at the moment anyway. I'll plan to stick with one or the other rather than mixing them. I respect and appreciate your guidance here.

I agree with Andy - definitely you don't want to high pass the sealed subs as that gives away all of the room gain goodness very down low that the sealed sub gives you which a ported sub does not.

To mix sealed and ported well, you effectively need to add delay at just the right frequencies to the sealed subs to mimic the delay characteristics of the ported subs (ported subs almost always have higher delays at very low frequencies near the port tuning and also phase rotation from the high pass filter below port tuning doing weird things) - this can be often accomplished well with judicious use of delays and all-pass filters - check out my MSO tutorial video in my sig below where I mix 2 sealed and 1 passive radiator sub which has similar challenges to mixing sealed and ported and also goes very much into the why and how to interpret phase plots to be your friend.

Truth be told, even mixing smaller ported with larger ported subs can be very tricky as the different port tuning ranges mean differing group delay characteristics alos requigin some of the same techniques as mixing sealed and ported.

That said, I also agree that mixing subs of any kind that have highly different group delay characteristics can be a challenge, and even with the right tools like MSO and a good DSP like MiniDSP, it can be hit or miss and dependent on room configuration as well. If you already have sealed subs, then I would recommend sticking with them (for what it's worth, sealed subs are my preference for their simplicity and the ease of mixing many of them of different sizes) - if you want it louder or more tactile, then just move them closer to the seating position, or get more of them.

 

[phoberus]

UMIK 2 mic

Any reason you use the UMIK-2 for MSO and not the cheaper UMIK-1?
I haven't any of them but want to buy one and start with MSO, but not sure if UMIK-2 is overkill

 

[klettermann]

<<<snip>>> If you're concerned about a lack of bass extension with sealed subs, I'd suggest reading René's post in this forum about how the zero-order room mode tends to counteract sub LF roll-off, giving more extended LF response than the sub's anechoic behavior would predict. He also has an article in AudioXpress on this topic that's even better than his post here. I highly recommend that article.

If you decide to mix sealed and ported, I can go into detail about the right way to do it in MSO. That's a lengthy explanation, so I'll defer that until I know exactly what you plan to do.

Isn't the whole REW/MSO dance fun? It took me a solid 6 months to learn it all well enough to get reproducible results that I was happy with.

Anyway, to the point. The above is fascinating and I have seen the same. I recently discovered that when playing at reasonably loud levels, the subs themselves are NOT subjectively very loud at all if the mains are muted. Yet turn on the mains and the whole low end fills in wonderfully. As a system the low end is far louder than you'd guess by just listening to the 2 subs alone. I was astonished by difference. I got 2 identical mid-market ported subs in diagonal corners and it's all time-aligned.

 

[scotchrocks]

Any reason you use the UMIK-2 for MSO and not the cheaper UMIK-1?
I haven't any of them but want to buy one and start with MSO, but not sure if UMIK-2 is overkill

No, there's no need to get the UMIK-2 over the UMIK-1 for MSO from what I understand. I just picked it up in case I wanted the additional features in the future. Well, it's the future now, and I still haven't used those features! I did end up using it again for Dirac calibration as well, but a UMIK-1 should also work just fine for that.

There's another thread here discussing UMIK-1 vs UMIK-2: https://www.audiosciencereview.com/forum/index.php?threads/umik-1-vs-umik-2.36912/

I think the general conclusion is that for room EQ purposes, the UMIK-1 is good enough.

 

[Dure16]

Yes I do.

I took measurements with sub dials at 80%, MiniDSP shared at 0db, REW at -12db, and AVR volume set to achieve peaks of 90-100db in the 30-60Hz range.

I had to set the MiniDSP shared level to -12db to get the right sub volume for Audyssey calibration.

Now that calibration is done, what is the right way for me to increase sub volume? Should I use MiniDSP shared gain or should I adjust the AVR gain? Does it matter?

 

[phoberus]

I took measurements with sub dials at 80%, MiniDSP shared at 0db, REW at -12db, and AVR volume set to achieve peaks of 90-100db in the 30-60Hz range.

I had to set the MiniDSP shared level to -12db to get the right sub volume for Audyssey calibration.

Now that calibration is done, what is the right way for me to increase sub volume? Should I use MiniDSP shared gain or should I adjust the AVR gain? Does it matter?

Hey, I took some measurements with similar loudness values, but instead of needing to reduce the level by -12 dB, I need to increase it by around +12 dB.
Did you measure directly with the miniDSP via the USB input or over the AVR? How much can MSO cut in your configuration (single EQ point and summed)?

I measured directly over usb with -12dB REW sweeps and miniDSP volume on 0dB, maybe I need to lower the miniDSP to -18dB to have a -30dB sweep like with audyssey

 

[Dure16]

Hey, I took some measurements with similar loudness values, but instead of needing to reduce the level by -12 dB, I need to increase it by around +12 dB.
Did you measure directly with the miniDSP via the USB input or over the AVR? How much can MSO cut in your configuration (single EQ point and summed)?

I measured directly over usb with -12dB REW sweeps and miniDSP volume on 0dB, maybe I need to lower the miniDSP to -18dB to have a -30dB sweep like with audyssey

I had a similar problem and replacing my Audyssey microphone fixed it. I have a feeling these microphones aren't the highest quality or always consistent.

I measured for REW with a UMIK-1 plugged into my PC. I measured for Audyssey calibration with the Audyssey microphone.