So after helping dozens of guys align subs on a facebook page I moderate peer pressure has won and I made a video on it. The channel was started really just to make this one video but I decided to cover everything. Here's the REW sub alignment walk through for those that may be interested.

https://www.youtube.com/watch?v=_A6gPCczhuU

Thank you so much for doing this!

 

Please

So after helping dozens of guys align subs on a facebook page I moderate peer pressure has won and I made a video on it. The channel was started really just to make this one video but I decided to cover everything. Here's the REW sub alignment walk through for those that may be interested.

Please update the first post or the description in the YouTube video with your room measurements and subwoofer location. That makes it easier for us to try out.

 

Great video!

 

So after helping dozens of guys align subs on a facebook page I moderate peer pressure has won and I made a video on it. The channel was started really just to make this one video but I decided to cover everything. Here's the REW sub alignment walk through for those that may be interested.

https://www.youtube.com/watch?v=_A6gPCczhuU

Very well done and excellent job of showing steps in detail. Have you done anything similar for impulse response?

 

So after helping dozens of guys align subs on a facebook page I moderate peer pressure has won and I made a video on it. The channel was started really just to make this one video but I decided to cover everything. Here's the REW sub alignment walk through for those that may be interested.

https://www.youtube.com/watch?v=_A6gPCczhuU

This is awesome on so many levels! thanks so much for making the videos. I watched this one (Episode 7) and left a comment with some questions that you could hopefully answer. Then I went back to watch all the videos beginning with Episode 1.

Great job!

 

Thanks Guys.

as for impulse no I've always done sweeps as it verifies placement and can look at other seats where as impulse doesn't. Also once two subs are aligned the virtual sub would be what sub 3 is aligned to. I just recently played with impulse but found it lacking and i like to work with a representation of what is heard.

 

Thanks a lot for this.

Regarding the gain matching, is it necessary to go through that whole process if you have two identical subs? Could you not just set the gain to the same position on each sub and call it a day?

 

Yeah I think i mention that but may not have. It still wouldn't hurt to verify but they should have the same output if the gain knob is in the same position. If they were heavy I'd probably just set the gains the same and roll on!

 

Just a heads up, in your video you say you need to purchase the miniDSP 2x4 control plug-in separately. According to the miniDSP 2x4 HD product page, the plugin is included with purchase.

 

Hey. So I have just gotten to the point where you have aligned the 2 subs. Will watch the rest later.

Regarding the miniDSP, In a two sub setup, I am a little confused as to its purpose vs. Audyssey (version that can calibrate 2 subs separately) - maybe you get into this later in the video? Since you leave the miniDSP connected after setup, I guess you would never use the second sub output on the receiver? Or should both minidsp inputs be used with receivers that can distinguish between the individual subs?

Does Audyssey bugger up the work done using REW?

One suggestion: given the length of the the video, it would be nice if you put time stamps in the description. i.e. umik purchase xx:xx, minidsp purchase xx:xx, calibrate sub 1 xx:xx, etc. Though, I know this would be a lot more work and you have probably had enough already.

 

Everything you asked is explained in the video. Why we only use one sub out even when 2 are available is mentioned several times and I also show how to setup minidsp routing.

Yeah I have some serious time in that video.. I have over 20 hours in it total. As I mention in the video I have links in the description for everything you'll need. Yes it's a little long but if you want to learn to set everything up that little bit of time spent watching it will save you days fiddling and guessing and honestly many just give up.

 

Ahhh.

I remember seeing that at the 10 minute mark the first time I watched. Couldn’t find it again when I was sort of skipping through looking for it again.

I will have to rewatch the EQ section again. Too much info (in a good way) for a single viewing for someone who has not seen this stuff before.

Thanks again for making this.

 

Totally understand. I'm the worlds worst about skimming through stuff and missing stuff then putting my foot in my mouth. It is a lot of info. For a few years I've been walking people through this over Messenger. You can imagine how painful that was for me and the guy trying to learn without a video to follow.

 

In a 2 sub situation, assuming one has used REW to determine the best location for each sub, I have a question:

If a guy has a receiver with Audyssey XT32 - where each sub is configured separately, doesn't the Audyssey routine determine the proper delays and whether to invert or not?

I am trying to understand if, for aligning subs, miniDSP provides a significant benefit over just using Audyssey XT32?

I get with miniDSP you can make changes on the fly and immediately see the impact of those changes via REW (which is no doubt beneficial), but after all is said and done, would one typically net out to basically the same end-result between miniDSP and XT32 for sub alignment?

 

With two subs only yes xt32 is an option. It doesn't always get it right, it also won't say hey sub 2 needs to be moved to fix that null at sub one. Room correction uses impulse to align subs and isn't as accurate especially with multiple seats and once you get more than two subs you're in minidsp territory for sure.

Bottom line, If placement is good xt32 often does fine aligning dual subs for one row but it needs to be verified via measurements and also as mentioned in ep 7 you need to verify main to sub alignment too.

 

Thanks.

Now that I've removed my back row of seating (and riser) and my single row now only has 2 seats (instead of 4), think I will re-figure out the proper sub placement with REW and then use XT32 and see what happens. MiniDSP would be nice, but at $300 CAD, would be nice if I could get away without it and put that money towards dual 15s.

 

@cdy2179, great job with video. Watched till 40 mins. A few points
1 - Always better to name your measurements. When you took measurement for first sub on front left, name that measurement Front Left instead of Sep 25. This will become very handy when you open the measurements sometime later.
2 - I saw that when you were aligning your subs, you did it manually. You don't have to do that anymore with REW. When you measure, you can use REW new feature called "Impulse Response Calculation" under Analysis tab. Select "Use acoustic timing reference" and when you are on Measurement tab, select your left speaker as a timing reference. Now when you take measurement, you will hear a squeaky sound followed by your regular measurement tone. Take 1 reading of each sub. Then use Overlay Window and go to impulse screen. There you'll see the impulse response of both subs. Zoom into the first peak of response for better viewing (Press Ctrl Key and the Right click and drag a window around the peak and then double click on the highlighted area). Once zoomed in, you'll see two different peaks. Using your mouse go to the peak of first impulse. Then press the CTRL button on keyboard and keep it pressed. Press right mouse button and keep it pressed and drag mouse to the next peak of other response. Once you do that, REW will draw a box and will also show the distance b/w the two peaks and also the difference in ms. That's the exact ms number you need to put in minidsp delay. Its calculated to precision.

Step 2 might seem a bit tedious but once you know how to do it, its real quick way to figure out the delay. Also, using the impulse response, you can easily determine if you have to inverse the phase of a sub. If the first peak of subs don't face the same direction, you need to invert one of the sub.
Hope this helps.

 

thanks!

I do normally label them and I do mention it in the video and explain it'll help them keep up with whats what.

I have played with impulse and do like it and yes it does really help to determine if phase should be reversed. Impulse Is timing based on one position and doesn't verify other seats or rows which I mention in the video. It also doesn't confirm sub placement is good and it doesn't look at the actual response. Also once two subs are aligned the the third sub is aligned to their virtual sub so timing of the 3rd sub and those proceeding it aren't always right. For instance in my room impulse wants my rear subs to have 10ms or so of delay but with sweeps I get negative summation when thats done. The front subs which I align first it does fine. I just find SPL graphs much more thorough and it's also the method used by Mark Seaton and many others in pro HT room tuning although some will use RTA and have mic arrays they still align off the response of course I'm sure some use impulse too.

That said I may do a video on it to help guys get the delay faster and then confirm with the response and tweak it for any similarity issues at other seats. Of course they'd have to confirm placement first using spl graphs.

Most guys watching the video this is all new so they're getting hammered with a lot of new stuff.

 

Thanks for the video, very informative and well explained!
I just tried this for 2 subs and this was the result:

So not that bad I was thinking. However, this was of course without my front speakers, and with my AVR set to 200Hz crossover (which is the max, to kind of "disable" the crossover during alignment, not sure if this is the way to go or not).
When I enable my speakers, still 200Hz crossover, this is the result:

And after changing crossover to 80Hz:

So isolated the subs are fine, but when adding the other speakers it's all messed up again

 

Thanks for the video, very informative and well explained!
I just tried this for 2 subs and this was the result:
View attachment 2629040

So not that bad I was thinking. However, this was of course without my front speakers, and with my AVR set to 200Hz crossover (which is the max, to kind of "disable" the crossover during alignment, not sure if this is the way to go or not).
When I enable my speakers, still 200Hz crossover, this is the result:
View attachment 2629038
And after changing crossover to 80Hz:
View attachment 2629036

So isolated the subs are fine, but when adding the other speakers it's all messed up again

Nice response.

It looks like you just have negative summation at the crossover point. Room correction doesn't always get this right. To do it manually check out this link here. Now keep in mind as you cross to the main you're crossing to a single source of bass so the response will not be as nice as you have with your subs. You just get the best summation you can to verify the sub distance is correct.

https://www.avsforum.com/forum/155-...ers-subs/1713458-mtg90a-s-multiple-subwoofers-mains-integration-how-thread.html





.

 

Thanks

cdy2179, Thanks for pulling this and your other tuning how-to videos together. Over the course of this year, had made multiple attempts to tune my subs with miniDSP 2x4 HD with mixed results. This past weekend, after reviewing your Episode 7 I have my best results to date. Thanks for taking the time to put this together. Well Done!

 

cdy2179, Thanks for pulling this and your other tuning how-to videos together. Over the course of this year, had made multiple attempts to tune my subs with miniDSP 2x4 HD with mixed results. This past weekend, after reviewing your Episode 7 I have my best results to date. Thanks for taking the time to put this together. Well Done!

Awesome! Good to know I didn't confuse you too much..

 

Hi there. I originally posted this in the same topic. But I moved her because it's more active and likely has more audience.

I had a few questions after watching all your videos. Specifically the order and process of doing things. I am more than willing to pay for your time to answer these questions if this is beyond what you'd answer in a forum post.

I have a room where the only place I can put subs are far right corner (where I have a mini-marty ported to 20Hz) and nearfield behind the couch. I have two cabinets sealed behind the couch with two 12" drivers each. The nearfields are wired together for a 4ohm load to one channel of my iNuke 6000 (actually NX6000D) and the marty is on the other channel. My Denon AVR can control both LFE channels independently.

Since I am completed limited to sub placement along the back wall, does the android RTA replacement for room crawl even matter? I guess I do wonder how import the position of the drivers are. The marty's baffle and port is currently facing directly into the back corner. I guess I could rotate it in any direction. Would facing out into the room be better? Would RTA tell me this? Same with the nearfields. I can put the baffle facing right into the couch (which is 18" from back wall) or turn them around facing the wall. I can move the two near fields about anywhere across the back wall. So either both behind the coach or one in the middle and one in back left corner.

Once I have this figured out I know I move on to gains for each sub channel. I understand how this works from your video and have no problem moving the subs into the middle of the room (in exact same position) to determine gain levels for each channel. But since I have 2 subs wired to the same iNuke channel, would I place them on top of each other for this measurement?

Once this is done, I move on to Rew. You state that Audessey should be turned off. Since I already ran it before, do I just wipe out all trim and distance measurements back to zero?

I also wasn't clear if Dynamic EQ should be turned on or off when running REW?

And then do I want to use the same EQ curve you use in your video where you're fairly flat from 20 – 33 Hz and then slowly drop down to 80Hz with about a 15db drop from 30 - 80? Or is this only if I don’t have Dynamic EQ, which I do.

Lastly, you state I can bypass the ASIO4ALL drivers by setting my crossovers as high as I can. I was confused as to which crossover? LFE? Or after setting speakers to small move all the 5 channels to as high as they go?

Thank you very much.

 

Hi there. I originally posted this in the same topic. But I moved her because it's more active and likely has more audience.

I had a few questions after watching all your videos. Specifically the order and process of doing things. I am more than willing to pay for your time to answer these questions if this is beyond what you'd answer in a forum post.

I have a room where the only place I can put subs are far right corner (where I have a mini-marty ported to 20Hz) and nearfield behind the couch. I have two cabinets sealed behind the couch with two 12" drivers each. The nearfields are wired together for a 4ohm load to one channel of my iNuke 6000 (actually NX6000D) and the marty is on the other channel. My Denon AVR can control both LFE channels independently.

Since I am completed limited to sub placement along the back wall, does the android RTA replacement for room crawl even matter? I guess I do wonder how import the position of the drivers are. The marty's baffle and port is currently facing directly into the back corner. I guess I could rotate it in any direction. Would facing out into the room be better? Would RTA tell me this? Same with the nearfields. I can put the baffle facing right into the couch (which is 18" from back wall) or turn them around facing the wall. I can move the two near fields about anywhere across the back wall. So either both behind the coach or one in the middle and one in back left corner.

The RTA will tell you if you have any nulls or dips that need fixing. When you turn a sub all you're doing is changing it's location in the room and nothing more. You can't "aim" a sub as the waves are so large they just pressurize the room.
The baffle is where the sound is produced so when you spin a sub you're acoustically moving it in the room.


Once I have this figured out I know I move on to gains for each sub channel. I understand how this works from your video and have no problem moving the subs into the middle of the room (in exact same position) to determine gain levels for each channel. But since I have 2 subs wired to the same iNuke channel, would I place them on top of each other for this measurement?

The two 12s are usually treated as individual subs but wired like you have them and considering they're two sealed 12s asked to play with a marty sub I'd maybe stack them and set the gain to equal the Marty.

Once this is done, I move on to Rew. You state that Audessey should be turned off. Since I already ran it before, do I just wipe out all trim and distance measurements back to zero?

Just go into the AVR and turn off audyssey. Nothing more needs to be done other than raising the crossover point to allow for sub sweeps

I also wasn't clear if Dynamic EQ should be turned on or off when running REW?

When you turn Audyssey off dynamic EQ will be turned off automatically.

And then do I want to use the same EQ curve you use in your video where you're fairly flat from 20 – 33 Hz and then slowly drop down to 80Hz with about a 15db drop from 30 - 80? Or is this only if I don’t have Dynamic EQ, which I do.

When using dynamic EQ which I recommend you'll use a flat target in the REW EQ screen. The manual house curve is only when not using Audyssey or similar auto room correction EQ.

Lastly, you state I can bypass the ASIO4ALL drivers by setting my crossovers as high as I can. I was confused as to which crossover? LFE? Or after setting speakers to small move all the 5 channels to as high as they go?

Set mains to small and set the crossover for the mains as high as it'll go. Usually 250hz. LFE LPF only affects the LFE channel, we are sweeping one of the mains which is being routed to the sub via bass management.

Thank you very much.

You're welcome!

.

 

Edit: never mind I found that you already addressed this earliest in the thread. Apologies.

Thank you so much. One more question. Without relistening to the 90 min video, did you say I should only use one LFE output to the iNuke and then use the DSP to control phase and delay for each output instead of Audessey?

 

Yes only use one AVR sub out. This way only you can mess with the alignment. The AVR will see one sub.

 

Thank you again. Sorry for the questions.

When running sweeps, what do I set the AVR to? Stereo or full surround? If stereo, I can’t get my subs to play unless I allow LFE + Main. This one has always baffled me. I have XT32 if that matters.

Once REW is done, I run Audssey. But what about the subwoofer distance it sets? Do I leave alone or wipe this out and rely completely on what iNuke DSP set?

 

TIf stereo, I can’t get my subs to play unless I allow LFE + Main. This one has always baffled me.

Are all speakers set to "Small"?

 

yup. But if I play as surround, the sub kicks on. All speakers are set to small.

 

Question about the positive sum mation measurement...

Yesterday I was trying to align 2 subs for my brother-in-law, and measured difference in distance from the listening position to each sub was only about a 1 foot. So I added 1 millisecond of delay the closet sub and the summed response got better but it was still not positive across the entire subwoofer frequency range. I added more and beyond 3 millisecond it looked like it was getting worse in some areas, particularly below 30Hz. When I reduced the daley back to 1.56 millisecond the low end summation improved, but the summation around the 70-90Hz range was never clearly above the to individual measurements. I also tried inverting the second sub it, but that yielded worse results in the 20 to 30 Hz range. Just wondering how far in excess of what the ruler measures should we consider going, and at what point would it not make sense anymore?

 

When you inverted, did you reset the delay to "0"? May or may not make a difference since you were dealing with a small delay.

Were you measuring subs only (LFE) from REW? Make sure there isn't a speaker active when performing sub alignment.

Depending on the room, the number of subs and the placement of the subs, positive summation across the entire bandwidth just may not be possible. Have you tried different placements, ones that compliment each other when measured individually?

 

This is awesome. I’ve been putting off getting a Minidsp and REW because of the learning curve but now I think I’m ready to proceed. Great job.

 

Thanks! Hope it makes it much easier for you.

 

Thanks for positing the video and starting the series; I'm looking forward to future installments. The video was straight to the point, and you laid out a very quick strategy to get some really nice responses. After just a few tests, it was easy to start flying through individual adjustments.

When measuring your first two subs, you started with the front left and then went to rear right. Was there a specific strategy behind this? I'm guessing that their the furthest subs from each other, and you were looking for contrast, and also to see if flipping the phase was going to have the desired effect. But by the end of the exercise, would it have made any difference in what order each sub was added?

When setting up multiple subs in the past, I spent a lot of time trying to multiple cuts to each sub in order to try and get a smooth curve, but it's a time-consuming process, with lots of trials, and even more errors. Have you tried to do any of that yourself? Just wondering if you've found any shortcuts that might be worth trying.

Scott

 

I did the front and rear subs first to just walk everyone through aligning some subs knowing that I would need delay there and show the "hunting" process. Normally you'd do as I do after that when I align them before EQ. Farthest sub is sub one then start adding subs to the group. If the farthest subs are equidistant you'll just makes sure they have positive summation and keep on rolling with adding sub 3.

As for EQ'ing individual subs. We aren't wanting to have each subs response flat and shouldn't care if each subs response is flat. The subs in room will naturally have peaks and dips and we want to place them based on that and then simply align for most positive summation at the seats. Then we can simply load and REW EQ file globally which as you see in the video EQ takes just a few minutes and really less than a minute if you're quick. If you EQ'd each sub individually you'd have some subs working much harder than others.

 

I just added some nearfield subs directly behind the coach. Since they literally make the couch shake, my wife hates it unless we're watching a movie. The other sub (a Marty Cube) is far enough a way that it doesn't bug her when just watching TV. Per your video, you recommend using a single LFE out from AVR into the DSP and then splitting out to the multiple subs. My one concern is both subs are now matched. So I feel the rumble in the couch even when watching football. Ideally I could turn down the nearfield during these times and only enable for movies. But with a single output from AVR, this wuold not be possible without manually changing the gain on the Behringer NX6000D.

But using both LFE outs on the AVR (Denon X3400H) would let me control this from the remote. Based on this, what would I be losing out on by using both LEF outs on my AVR?

Thank you.

 

You can get a remote for the MiniDSP (or teach it to use literally any IR remote) and it will let you change configs with a single button press. You can also do this with the MiniDSP app. Set up one config for full-on "Movie Mode" and another for "Laid-back TV Watching Mode" and you're all set.

As an aside; if you are feeling an over-abundance of rumbles during football, you may have your NF sub turned up a bit to high. Also, if you are using different inputs on the AVR for movies vs TV, you could try changing some of the settings for the TV input (if you are using DEQ, set the RLO down to -15, if you have LFC on your AVR, turn that on, turn Subwoofer Adjust down for that input, etc.).

 

No MiniDSP me for. I have the Behinger NX6000D with the built in DSP. Thus, not remote.

But your second suggestion sounds really good. I never use my TV input for anything requiring bass. Thanks.

 

No MiniDSP me for. I have the Behinger NX6000D with the built in DSP. Thus, not remote.

I guess since you said "you recommend using a single LFE out from AVR into the DSP and then splitting out to the multiple subs.", I assumed you were considering getting one.

But your second suggestion sounds really good. I never use my TV input for anything requiring bass. Thanks.

You're welcome. Let us know how it goes!

 

First off, thank you for putting together this in-depth video. I watched the first 30 minutes after watching #8 on gain-level matching. I did some searching for videos and posts for reference about 6 weeks ago on REW. This video is so much more comprehensive and helpful than what I was able to find.

I've attached the before, targeted, and corrected curve from ARC-Genesis to see what I'm currently working with.


Before I begin the task, I have a few questions. Please forgive me if these were answered in the forum and I’ve missed the answers to them.

1) Do I still need to level match my subs if they are identical? In video #8 at the 11:35 mark while talking about the hassle of moving speakers around you say, “Luckily mine are all identical subs,” and that they are running off the same processor, so you’re okay.

2) In REW, when you are doing the initial sweep to see what each sub’s room response is, are you moving the UMIK or the sub across the couch? You say your moving “it” as though it’s the sub. However, the time between sweeps leads and the fact that you’re trying to get different positioning leads me to believe you’re talking about the UMIK.

3) Is it okay to run the sweeps off to the side of my room just out of the direct path of the closest sub and FR speaker?

4) Since I’m only using REW to set up my subs, do I need to connect an HDMI or a USB cable to my receiver from my computer, or will I only have the following connections:

Receiver to MiniDSP to Subs
MiniDSP to Computer
UMIK-1 to Computer


Thank you in advance!

 

1) Do I still need to level match my subs if they are identical? In video #8 at the 11:35 mark while talking about the hassle of moving speakers around you say, “Luckily mine are all identical subs,” and that they are running off the same processor, so you’re okay.

2) In REW, when you are doing the initial sweep to see what each sub’s room response is, are you moving the UMIK or the sub across the couch? You say your moving “it” as though it’s the sub. However, the time between sweeps leads and the fact that you’re trying to get different positioning leads me to believe you’re talking about the UMIK.

3) Is it okay to run the sweeps off to the side of my room just out of the direct path of the closest sub and FR speaker?

4) Since I’m only using REW to set up my subs, do I need to connect an HDMI or a USB cable to my receiver from my computer, or will I only have the following connections:

Receiver to MiniDSP to Subs
MiniDSP to Computer
UMIK-1 to Computer

1) Gain matching, not level matching. If your subs are identical, you can set the gain knobs to the same setting and you should be golden.

2) Moving the mic to measure different listening positions, not moving the sub(s).

3) When running sweeps, you want the mic to be placed at the MLP at ear height, and subsequently at other listening positions (if you are concerned about their response). Why would want to measure off to the side of the room? Do people sit there??

4) Yes, you have to have the computer connected to the AVR via HDMI, how else will you (and the mic) be able to hear the sweep?

Hope this helps!

 

Your welcome!

That makes more sense...yes, you can be off to the side when measuring, you don't want to be sitting in the MLP, for obvious reasons.

An older HDMI cable should work just fine for REW's purposes.