Anyone willing to help a beginner with proper setup?

fishinfool

New Member
Thread Starter
Joined
Apr 10, 2019
Messages
6
I've read some conflicting information and I'm not to sure on the right way to setup a mindsp for optimizing subwoofers. A while back I used REW to try and flatten out two subwoofers, both located in the front of the room. Fast forward, I recently acquired another subwoofer and placed it in a back corner. That led me to looking into how to do it all over again and I came across Multi-Sub Optimizer. I ordered the minidsp-HD in hopes of eventually learning how to use MSO along with REW.

The first time I used REW, I used a laptop to run REW straight into the minidsp and directly out to the subs bypassing my AVR. I have a Win10 HTPC hooked up to my AVR, would it be better to run REW test tones on the HTPC out through the LFE on the AVR to the minidsp? And if so is there anything I should do with the AVR first?

ANy help would be appreciated, Thanks for looking.
 

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
2,131
There's nothing wrong with going straight to the miniDSP. To use MSO you will need a timing reference, either a loopback connection (if you are using a soundcard for input and output) or another loudspeaker that can provide an acoustic timing reference (if you are using a USB mic like a UMIK-1).
 

fishinfool

New Member
Thread Starter
Joined
Apr 10, 2019
Messages
6
There's nothing wrong with going straight to the miniDSP. To use MSO you will need a timing reference, either a loopback connection (if you are using a soundcard for input and output) or another loudspeaker that can provide an acoustic timing reference (if you are using a USB mic like a UMIK-1).
Thank you for the reply.

I am using the UMIK-1, and I can't seem to wrap my the around how the loopback works with it. Both my laptop and HTPC have headphone outputs and mic inputs. I also have an old external usb Diamond audio sound card that I could use if needed. Would I take one of the line outs of the minidsp and plug that into the mic input? or do I have to use the loudspeaker method with the UMIK-1?

Again, Thanks for the help.
 

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
2,131
Yes, with a USB mic you need to use the acoustic timing reference, it was made to cover that situation. There's no way to create an electrical loopback with USB mics so an acoustic timing signal is used instead, the software detects that signal and uses it as a reference. It needs to come from a speaker with a tweeter though, it is a high frequency sweep to provide sufficient precision for timing. The reference speaker and the mic need to stay in the same positions for the relative timing to make sense, typically the mic would be at the listening position and the reference speaker anywhere convenient - one of your main speakers, for example.
 

fishinfool

New Member
Thread Starter
Joined
Apr 10, 2019
Messages
6
OK, its making more sense now. Honestly I can't thank you enough, this is getting me pointied in the right direction. The only way I can think of to power a speaker would be to use REW and MSO on the HTPC. So, UMIK-1 into the HTPC then output via HDMI to the AVR, unplug all speakers but one (maybe center?) from the AVR, then the LFE outs on the AVR to the inputs on the minidsp and out of the minidsp to each sub? Then take multiple measurements at every listing position for each subwoofer individually and only moving the mic when changing listening positions. Does this sound like it will work?

Thanks again, this has helped me a whole lot.
 

JStewart

Senior Member
Supporter
Joined
Dec 5, 2017
Messages
362
Location
Central FL
Welcome to the forum!

The only way I can think of to power a speaker would be to use REW and MSO on the HTPC. So, UMIK-1 into the HTPC then output via HDMI to the AVR
Yes this is correct. And be sure to turn off all dsp sound altering programs in the AVR before measuring.

unplug all speakers but one (maybe center?) from the AVR, then the LFE outs on the AVR to the inputs on the minidsp and out of the minidsp to each sub?
I would recommend connecting the minidsp to either the right or left speaker pre-out of the AVR and disconnecting the associated left or right speaker. Then using the other speaker (left or right) for the timing reference in REW. Set the left and right speakers to large. This way you're taking the bass management XO out of the picture and also won't be limited by the typical 120hz low pass on the LFE channel and can then measure the sub over its range accurately. Do your sub sweeps up to 300hz. MSO will allow you to set the range you wish to correct to less than that if you wish.

Then take multiple measurements at every listing position for each subwoofer individually and only moving the mic when changing listening positions. Does this sound like it will work?
Yes. Its also helpful to number the subs and positions and name them that way in rew to keep track of which measurement is which when the REW measurements are exported from REW and then imported to MSO. So for example your measurement names would be S1 P1, S1 P2, and so forth.
 

fishinfool

New Member
Thread Starter
Joined
Apr 10, 2019
Messages
6
Good deal, I think I can manage most of that. Great tip on naming the measurements in REW. Thank you, all of this is a huge help.

I would recommend connecting the minidsp to either the right or left speaker pre-out of the AVR and disconnecting the associated left or right speaker.
I don't think I'll be able to manage the above with my cheapy AVR. It literally only has three outputs, 1 HDMI, and 2 LFE. excluding the speaker terminals. I can turn off all the mcacc filters and bypass the the EQ, but I believe that's about it. In this situation would it be best to leave the speakers set to small?

Another possible option. I could order a small class d amp and run everything on a laptop. From the laptop 3.5 out into the minidsp, then out to the amp board, then out of the amp into a little bookshelf speaker and the high level inputs on the subs. Not sure if that would even work. I don't know, what do you guys think?
 

JStewart

Senior Member
Supporter
Joined
Dec 5, 2017
Messages
362
Location
Central FL
It literally only has three outputs, 1 HDMI, and 2 LFE
You’ll have to use the LFE channel for the measurements then. Run the REW sweeps to 300 still and if the spl starts to fall off at 120hz or so then just limit the range mso corrects to 100hz or so. If you’re lucky there won’t be a low pass on the LFE channel. Didn’t see a reference in the manual.

EDIT: I just spotted in the OM the XOs can be set to 200hz so ignore above and set fronts to small, disconnect one of the front speakers and send the rew sweep to it. Bass mgmt will direct the signal to the sub. Use the other front speaker for Rew timing reference.

I can turn off all the mcacc filters and bypass the the EQ, but I believe that's about it.
I looked at the link to the OM you provided. Pure direct mode looks like what you need.

In this situation would it be best to leave the speakers set to small?
Rew’s acoustic timing chirp should be well above any xo set so it won’t matter.

Another possible option. I could order a small class d amp and run everything on a laptop. From the laptop 3.5 out into the minidsp, then out to the amp board, then out of the amp into a little bookshelf speaker and the high level inputs on the subs. Not sure if that would even work. I don't know, what do you guys think?
I think I’d see what improvement I could get first. There’s potential for quite a lot.
 
Last edited:

fishinfool

New Member
Thread Starter
Joined
Apr 10, 2019
Messages
6
I think I’d see what improvement I could get first. There’s potential for quite a lot.
Sounds good I'll give it a shot. Still have a whole lot to learn but I feel like I have a solid direction now and will hopefully be able read up on everything else. I really appreciate you taking the time to lend a hand, thanks again.
 

fishinfool

New Member
Thread Starter
Joined
Apr 10, 2019
Messages
6
Hi, just wanted to chime back in and thank you both again for helping me get started. Honestly it was a ton of help. Everything sounds great, definitely better than it ever has. I was even able to better time align a few tactile transducers. Everything just seems super cohesive now. The bass is kind of just all encompassing now, vs before I could pinpoint the subs with my eyes closed.
 

JStewart

Senior Member
Supporter
Joined
Dec 5, 2017
Messages
362
Location
Central FL
Hi, just wanted to chime back in and thank you both again for helping me get started. Honestly it was a ton of help. Everything sounds great, definitely better than it ever has. I was even able to better time align a few tactile transducers. Everything just seems super cohesive now. The bass is kind of just all encompassing now, vs before I could pinpoint the subs with my eyes closed.
Sweet. @andyc56 is a rock star for developing MSO and sharing it with all of us.
 
Top Bottom