Always want Positive Sumation for dual subs?

Nakean

Nakean

Junior Audioholic
Do you always want positive summation when dealing with placement and phase/delay? Or does it make more sense to adjust the phase and delay to get the evenest response in the room and then EQ to taste?

With positive summation, you would treat both subs as one once phase-aligned and EQ the single input

When not using positive summation I can eq each sub directly to impact the response of the other. This is how I originally set up my subs. The response is only flat at MLP but that's all that really matters in my space.

Thoughts?
 
Nakean

Nakean

Junior Audioholic
What is positive summation?
more db gain across entire frequency response, regardless of peaks and nulls, with both subs vs any single sub OR more even response with the second sub which would not necessarily mean a net positive gain when summing both subs but a more even response.
 
lovinthehd

lovinthehd

Seriously, I have no life.
Can't say I see the point of merely having higher spl vs smoother response. Generally you would eq subs as a single entity, tho.
 
lovinthehd

lovinthehd

Seriously, I have no life.
I guess I'm just curious about starting points pre EQ
Besides time aligning them and working on smoothest response over as wide an area as you can (or need)? Depends on the tools you have to do so, too....
 
Nakean

Nakean

Junior Audioholic
Mini DSP and Umik to work with. Each sub as its own amp as well. Just watched video and the person talked about gain matching first and time alignment to make sure subs all summed to equal greatest output before he eq'd. He had simple rectangular room, however. I have an odd layout with openings. I figured aligning subs so that response was as even an flat as possible at MLP before EQ was most important. That's what I did. Then after watching wondered if it would have been better to get both subs to sum with greatest SPL and then eq for flat response. Probably just over thinking it. I time aligned for smoothest response then manually eq'd each separate sub to interact with each other for flatter response. Then used REW with EQ to generate an overall EQ for smoothest response, treating both subs as single sub for the last eq run.
 
M

Muad'dib

Audiophyte
Mini DSP and Umik to work with. Each sub as its own amp as well. Just watched video and the person talked about gain matching first and time alignment to make sure subs all summed to equal greatest output before he eq'd. He had simple rectangular room, however. I have an odd layout with openings. I figured aligning subs so that response was as even an flat as possible at MLP before EQ was most important. That's what I did. Then after watching wondered if it would have been better to get both subs to sum with greatest SPL and then eq for flat response. Probably just over thinking it. I time aligned for smoothest response then manually eq'd each separate sub to interact with each other for flatter response. Then used REW with EQ to generate an overall EQ for smoothest response, treating both subs as single sub for the last eq run.
In my 2 sub system, the best results are:

Gain max each sub to same spl.
Then.
Set both subs combined to have the max spl you can achieve..
Then, use a room eq or sub eq to smooth out the combined subs as one.
Then play with sub distance on stereo receiver to best align the combined subs with main channels...
 
lovinthehd

lovinthehd

Seriously, I have no life.
In my 2 sub system, the best results are:

Gain max each sub to same spl.
Then.
Set both subs combined to have the max spl you can achieve..
Then, use a room eq or sub eq to smooth out the combined subs as one.
Then play with sub distance on stereo receiver to best align the combined subs with main channels...
You mean gain match?
 
Nakean

Nakean

Junior Audioholic
In my 2 sub system, the best results are:

Gain max each sub to same spl.
Then.
Set both subs combined to have the max spl you can achieve..
Then, use a room eq or sub eq to smooth out the combined subs as one.
Then play with sub distance on stereo receiver to best align the combined subs with main channels...
Yes, you might want to clarify that your gain match is either with the same SPL with both subs in the exact same spot so you eliminate the room or measured 6in away from driver to try and do the same.
 
M

Muad'dib

Audiophyte
Yes, you might want to clarify that your gain match is either with the same SPL with both subs in the exact same spot so you eliminate the room or measured 6in away from driver to try and do the same.
Sorry Meant to add more info..

In my system I found this to work best..

I use subs in their best positions as compared to measuring subs in same spot for gain.. I want room to influence bass when doing spl. As when all done, they will be in different positions from each other anyway..

1- Find best locations for each sub.. And put each sub in those locations..
2 - each sub seperate, use a SPL meter at MLP and set levels to 72db for each sub seperate.
3- now run REW.. Measure each sub seperate, then together.
4- look at combined to see if you get a total max positive summ.
5- If you adjust closest sub phase (or distance) to align with other sub to get max spl summ. Try for fun inverting one subs phase from 0 to 180. and see if things get way worse or better.
Sometimes, the subs will be out of phase from the start, and you won't get a great max spl summ.

hope this helps a little.. I'm no expert by any means, but this seems to work great at my system.
 
Nakean

Nakean

Junior Audioholic
Sorry Meant to add more info..

In my system I found this to work best..

I use subs in their best positions as compared to measuring subs in same spot for gain.. I want room to influence bass when doing spl. As when all done, they will be in different positions from each other anyway..

1- Find best locations for each sub.. And put each sub in those locations..
2 - each sub seperate, use a SPL meter at MLP and set levels to 72db for each sub seperate.
3- now run REW.. Measure each sub seperate, then together.
4- look at combined to see if you get a total max positive summ.
5- If you adjust closest sub phase (or distance) to align with other sub to get max spl summ. Try for fun inverting one subs phase from 0 to 180. and see if things get way worse or better.
Sometimes, the subs will be out of phase from the start, and you won't get a great max spl summ.

hope this helps a little.. I'm no expert by any means, but this seems to work great at my system.
Thanks! That's basically How I did everything. I'm fairly happy with the results but I moved my subs to the front of the room and use them as stands for my Heresy's now. I do love that I can no longer localize even if I move the Xover to higher frequencies like 110hz but I have lost a bit of that rumble I had when used them nearfield. I'm not sure which I like better yet but I think it's nearfield, if only for the reason that I can get rumble to my seat in the evening (when kids have gone to bed and wife might not be watching) then I can if they are up front pressurizing the room. Going to leave them where they are for a bit longer before I piss off my wife and move them again...

And or I move some smaller subs nearfield while keeping the others under the LR speakrs...hmm...
 
KEW

KEW

Audioholic Overlord
Thanks! That's basically How I did everything. I'm fairly happy with the results but I moved my subs to the front of the room and use them as stands for my Heresy's now. I do love that I can no longer localize even if I move the Xover to higher frequencies like 110hz but I have lost a bit of that rumble I had when used them nearfield. I'm not sure which I like better yet but I think it's nearfield, if only for the reason that I can get rumble to my seat in the evening (when kids have gone to bed and wife might not be watching) then I can if they are up front pressurizing the room. Going to leave them where they are for a bit longer before I piss off my wife and move them again...

And or I move some smaller subs nearfield while keeping the others under the LR speakrs...hmm...
Sounds to me like you might want to add one of these (you screw or bolt it solid to the frame of your chair)!

You'll also need an amp for it:
 
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William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
The Hideaway Theater

You wanna shake the couch? This is how you do it. It’s also basically silent so if you wanna blow up the couch and not wake anyone, turn off the far field subs(or not lol) and just use the boss. It’s much more linear than normal shakers and since it uses speakers, the platform acts the same way. Awesome.
 
Nakean

Nakean

Junior Audioholic
Sounds to me like you might want to add one of these (you screw or bolt it solid to the frame of your chair)!

You'll also need an amp for it:
The Hideaway Theater

You wanna shake the couch? This is how you do it. It’s also basically silent so if you wanna blow up the couch and not wake anyone, turn off the far field subs(or not lol) and just use the boss. It’s much more linear than normal shakers and since it uses speakers, the platform acts the same way. Awesome.
I always thought these things were gimmicks. Are they not? This is kind of exciting if they're not.
 
lovinthehd

lovinthehd

Seriously, I have no life.
I use a sub right behind my seat as well as a tactile transducer under it...try it, you might like it.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
I always thought these things were gimmicks. Are they not? This is kind of exciting if they're not.
My experience with most shakers was a little like that. A little bit cheesy, and not integrated well. That could be from cheap ones as well as possibly not being set up properly. Ime crowson and Clarke are worth looking at. But that boss platform is so much more. Some guys use them together. But imo, set up right it’s just a natural extension of the subs. I’ve seen videos of people spilling water glasses and knocking remotes on the floor. If you’re serious, I’d do a BOSS. It can easily be cheaper too.
 

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