The Perfect Solution for Home Theater Bass Optimization Here!

[Speedskater]

Yes the UMM-6 is good for the price but I believe its only accurate down to 18Hz. I had Dayton send me one last week so I will test it and report back. Glad you're focusing on the bass via multi-sub rather than bouncing sound for Atmos. Good choice!

Once we get below 18 Hz, accuracy has little meaning in a real world listening room.

 

[Omzig]

Yes I was referring to the HD version of unbalanced unit which does have 2Vrms out. I wouldn't use a device that can't do 2Vrms for a sub channel. Sorry for the confusion.

7.5 ms of delay is a bit short but in my 26x27ft room, all I needed was 3ms relative to the other subs and it did the job nicely.

I will likely be adding an unbalanced HD version to my family room system in the coming months and may do a short followup article on it.

I just ordered the standard (non HD) version. Does this mean I won't be able to use it to EQ my sub (Audio Concepts Titan)?

 

[etc6849]

Are the waterfall plots in the article not using the default REW smoothing (1/48th octave for waterfall plots)? If not, what curve smoothing was used? Thanks!

 

[d6500k]

I have been reading and watching the videos regarding this topic for a spell now. While I have not bought the Mini dsp, I did acquire another twin Sub to match my venerable M&K v75 (not the mark 2) the newer twin is the v 125 and is the same in all regards save for amplification.

FYI, I have a small and I mean small 12'x10'x8' room. The pj shoots from inside a closet with the doors removed, thus the 10' dimension. I sit 9' from the screen and just less than 8' from the mains and the subs. The subs are each along the front wall between the mains (Def Tech SM 65's Fr, C, FL If that matters) the arrangement allows for the subs to be 1/3 distance from the side walls.

The subs have been level matched and Audessey multi EQ employed and engaged. With some minor adjustments and pulling the subs out a bit into the room (about 8"...small room necessity) I do receive a very nice blend on the front soundstage ( I did set the LPF on my avr to 80hz as recommended with the filter on the subs maxed at the top of their dial, 120hz.

So after the too long preamble.... my question.

Running Audessey with 5 mic measurements does produce a nice sound save for one caveat.
The LFE from the subs are noticeably louder just 2 or 3' ABOVE my head. Nearly 6 db when measured with my SPL meters (radio shack and Tablet/Phone apps).

Would the implementation of the Mini dsp and REW be able to move the "sweet spot" down those 2 or 3 feet to get my head in the game (so to speak)?

Again, all speakers when leveled with Audessey or the test tones generated by my AVR or through my BD players and test disks are spot on at 75db.

Thanks for the help ahead of time. My ISF training has my image and a couple of hundred other displays calibrated to accuracy dependent upon the displays abilities. Now retired form that game, I am trying to dial in the audio as best I can given the room, (which I cannot change until I move again...Lord help me)

All the Best!
Doug

 

[Wellz]

Gene,

Thanks again for the work you and your team do. If I may, I'd like to request that when you make the video and/or write-up on how you used REW with miniDSP to achieve your results, please take a minute to explain to us non-propeller heads, how exactly it was that you measured each of your subs, interpreted the measurements and decided where to tweak. Like many on this forum, I went ahead and purchased the miniDSP to get better seat to seat consistency from my two SVS sealed Subs. Over the last week and a half I probably took over 200 measurements. Unfortunately without fully understanding how to interpret each and then combine them, I ended up with mixed results seat to seat. It seems like every time I tried to fix the measurement for one of the five seating positions, it would then throw off the measurement in a different seat...Like that was chasing my own tail! It would be great to see the methodology that led to your success. I know some of this may seem basic for some, but I can assure you that it would be a great help to many of us who are trying to achieve similar results to yours and don't have the technical background.

Both the video and the article that you initially did for the MIniDSP, make reference to adjusting delays, tweaking the EQ for each sub individually and then together. It would be great to see exactly how and where you did that. The graphs that you showed are phenomenal considering what they looked like before and after. Thanks again, I look forward to the write up/ video.

 

[andy_c]

Like many on this forum, I went ahead and purchased the miniDSP to get better seat to seat consistency from my two SVS sealed Subs. Over the last week and a half I probably took over 200 measurements. Unfortunately without fully understanding how to interpret each and then combine them, I ended up with mixed results seat to seat. It seems like every time I tried to fix the measurement for one of the five seating positions, it would then throw off the measurement in a different seat...Like that was chasing my own tail!

I've written a free software program called Multi-Sub Optimizer (MSO) to help with this problem. To use it, you make individual measurements of main speakers and each sub at each listening position you wish to optimize. Measurements must be made using REW's acoustic timing reference feature to ensure time-synchronized measurements. Then you export each measurement to a text file using File, Export, Measurement as Text in REW. You import these files into MSO, and define your filter channels and associate these channels with the corresponding measurements you imported. You specify what kind of filters to use in each channel, and which measurements to sum together for each listening position. Then you run the optimization. Here is a "before and after" example with four subs and four listening positions.

In this project, there were four subs, one pair of main speakers driven in mono, and four listening positions. So there were five measurements for each listening position, times four positions, for a total of 20 measurements. The optimization was run for about a half hour. If there were e.g. 1 million iterations of the optimizer, this would be the equivalent of trying out 1 million combinations of filter, delay and gain parameters and doing a measurement of the combined mains and subs for each of four listening positions, for a total of 4 million equivalent measurements. It's a lot easier to let the software do the work. You can see the optimization "runs out of gas" above about 100 Hz, because EQ is only applied to the subs, not the main speakers (although you can if you wish, and if your hardware supports it). Also, all PEQ filters used were cut-only, no boost.

For a manual procedure, you might check out this thread.

Edit: I just uploaded a new version, v1.10 this evening.

 

[Wellz]

I've written a free software program called Multi-Sub Optimizer (MSO) to help with this problem. To use it, you make individual measurements of main speakers and each sub at each listening position you wish to optimize. Measurements must be made using REW's acoustic timing reference feature to ensure time-synchronized measurements. Then you export each measurement to a text file using File, Export, Measurement as Text in REW. You import these files into MSO, and define your filter channels and associate these channels with the corresponding measurements you imported. You specify what kind of filters to use in each channel, and which measurements to sum together for each listening position. Then you run the optimization. Here is a "before and after" example with four subs and four listening positions.

In this project, there were four subs, one pair of main speakers driven in mono, and four listening positions. So there were five measurements for each listening position, times four positions, for a total of 20 measurements. The optimization was run for about a half hour. If there were e.g. 1 million iterations of the optimizer, this would be the equivalent of trying out 1 million combinations of filter, delay and gain parameters and doing a measurement of the combined mains and subs for each of four listening positions, for a total of 4 million equivalent measurements. It's a lot easier to let the software do the work. You can see the optimization "runs out of gas" above about 100 Hz, because EQ is only applied to the subs, not the main speakers (although you can if you wish, and if your hardware supports it). Also, all PEQ filters used were cut-only, no boost.

For a manual procedure, you might check out this thread.

Andy,
I'm excited to test your MSO program. So a to not take away from this thread, I will send you a private message to discuss it.

 

[Ted Timmis]

Gene,

Let me preface my remarks by saying that I have watched most of your videos and enjoy them very much. You are very knowledgeable, articulate and perhaps OCD. You're a man who says things the way they really are. However, I am very confident in saying that the vast majority of people, myself included, and even most of the self-proclaimed audiophiles who post comments on these forums, have no idea what you are talking about when you casually make technical assumptions or launch into technical conclusions.

Don't be fooled by the knowing nods and pithy comments from your followers. If you queried your followers, you would find that most (and again, myself included) don't understand, perhaps with the exception of a few with advanced degrees in physics or engineering or those who have made it their life's mission to study these things.

To borrow a phrase from legal pedagogy, you fail to lay the proper foundation for many of your technical comments and assume facts not in evidence. Or to put it another way, it's like stating the answer to a math problem without showing the calculations which led to your conclusions.

Don't get me wrong, I don't think it's your responsibility to dumb things down for neophytes like me. If I want to learn at the feet of the master, then it's up to me to learn the meaning of things such as standing waves, phase, delay, gain or fall-off. Moreover, if I lack the IQ to comprehend, again that is not your problem. If I come to your school, I must come with a certain level of aptitude and when I come to your class, it's up to me to do my homework. However, I think you would greatly broaden your appeal if you took the time to lay the proper foundation and explain in greater detail how you arrive at your conclusions.

 

[John Rett]

Hey @gene , I'm in a similar situation. I have a pair of NHT 2.9 which has 2x10in sealed subwoofers bi-amps with the other drivers. I would like to use them as subwoofers with a miniDSP, but I am trying to understand something. How did you set the crossover in your receiver for the fronts? You say you set them to small, but at what frequency?

Maybe a better way to put my question. Do your fronts have a passive crossover, or did you bypass it somehow? My NHT 2.9 have a passive LP/HP at 100Hz for the subwoofers, and I'm trying to figure out how to work around that with the miniDSP and the receiver crossover setting.

The only solution I can think of is setting them to Large, then sending summed L/R signal to the 2nd input of the miniDSP. Do you have any better ideas? Thanks!

 

[MR.MAGOO]

$800 seems kind of expensive. I checked miniDSP.com.

 

[lovinthehd]

$800 seems kind of expensive. I checked miniDSP.com.

Expensive for a Dirac enabled unit? Not the minidsp units discussed mostly in this thread either....

 

[MR.MAGOO]

Expensive for a Dirac enabled unit? Not the minidsp units discussed mostly in this thread either....

so this what I need?

https://www.amazon.com/miniDSP-revA-2x4/dp/B014SJ420M/ref=sr_1_1?ie=UTF8&qid=1482782822&sr=8-1&keywords=mini+dsp+2x4+hd

 

[lovinthehd]

so this what I need?

https://www.amazon.com/miniDSP-revA-2x4/dp/B014SJ420M/ref=sr_1_1?ie=UTF8&qid=1482782822&sr=8-1&keywords=mini+dsp+2x4+hd

Maybe. What do you want to do?

 

[MR.MAGOO]

Maybe. What do you want to do?

optimize 2 subwoofers

 

[lovinthehd]

Then that would be a good choice.

 

[MR.MAGOO]

Then that would be a good choice.

Thanks for the answers, I just want to make sure I'm on the right track before spending $$$. If it doesn't work out I can always send it back to Amazon.

 

[lovinthehd]

Do you already have measurement mic/REW?

 

[gene]

Gene,

Let me preface my remarks by saying that I have watched most of your videos and enjoy them very much. You are very knowledgeable, articulate and perhaps OCD. You're a man who says things the way they really are. However, I am very confident in saying that the vast majority of people, myself included, and even most of the self-proclaimed audiophiles who post comments on these forums, have no idea what you are talking about when you casually make technical assumptions or launch into technical conclusions.

Don't be fooled by the knowing nods and pithy comments from your followers. If you queried your followers, you would find that most (and again, myself included) don't understand, perhaps with the exception of a few with advanced degrees in physics or engineering or those who have made it their life's mission to study these things.

To borrow a phrase from legal pedagogy, you fail to lay the proper foundation for many of your technical comments and assume facts not in evidence. Or to put it another way, it's like stating the answer to a math problem without showing the calculations which led to your conclusions.

Don't get me wrong, I don't think it's your responsibility to dumb things down for neophytes like me. If I want to learn at the feet of the master, then it's up to me to learn the meaning of things such as standing waves, phase, delay, gain or fall-off. Moreover, if I lack the IQ to comprehend, again that is not your problem. If I come to your school, I must come with a certain level of aptitude and when I come to your class, it's up to me to do my homework. However, I think you would greatly broaden your appeal if you took the time to lay the proper foundation and explain in greater detail how you arrive at your conclusions.

Ted,

Sorry for my belated reply. I greatly appreciate your feedback and will work on better explaining technical stuff in layman terms. You're right, I often make assumptions that our general audience understands everything I discuss when in reality only a small fraction of audience does.

 

[gene]

Hey @gene , I'm in a similar situation. I have a pair of NHT 2.9 which has 2x10in sealed subwoofers bi-amps with the other drivers. I would like to use them as subwoofers with a miniDSP, but I am trying to understand something. How did you set the crossover in your receiver for the fronts? You say you set them to small, but at what frequency?

Maybe a better way to put my question. Do your fronts have a passive crossover, or did you bypass it somehow? My NHT 2.9 have a passive LP/HP at 100Hz for the subwoofers, and I'm trying to figure out how to work around that with the miniDSP and the receiver crossover setting.

The only solution I can think of is setting them to Large, then sending summed L/R signal to the 2nd input of the miniDSP. Do you have any better ideas? Thanks!

You can set them large if the MT in your speakers have a HPF BUILT in, otherwise set them small. Send the sub/lfe out of your AVR to a power amp and then to the subs in your NHT.

 

[MR.MAGOO]

Do you already have measurement mic/REW?

I have REW, and just ordered miniDSP and a umik-1