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What process did you use to integrate multiple subwoofers for 2 channel listening?

Today I will be trying to integrate up to three subs. Two are matching Rythmiks F12SE, and one is a REL R-328. The Rythmiks have a variety of adjustable parameters, including phase, crossover, and gain. There are other switches and passes on the sub, but I'm going to try to keep it basic to begin with. The REL has variable gain and crossover; the phase on REL is either 0 or 180.

I have REW for measurement. I will be buying a few more furniture sliders this morning, on doctors orders. ;-)

QUESTION: If you have multiple subs, by what process did you integrate your subs? One at a time? More? Which adjustments did you try first and in what kinds of increment?

I know that trial, error, measuring, and listening will all take time. Rather than look for a needle in a haystack, I'm curious what sequence or process was most effective for you.

Thank you.
128x128hilde45
audiokinesis
2,747 posts
 
@hilde45 wrote: "...the orange "morning" line is speakers only.  Improvement from "Morning scan, without subs" to "Afternoon scan, with subs" mitigates the dip significantly at various points, e.g. pulling up a null by 10 db at 129 hz, by 8 db at 241hz."   

Maybe I'm just slow, but eyeballing the curves I would have thought that Orange was WITH subs, and Green was speakers ONLY.   

Anyway assuming that's the only difference, AND that the microphone locations and other measurement conditions are identical, the curves imply that the subs are active pretty high up.  Where are you rolling off the top end of the subs?  

Incidentally the dip around 270 Hz and peak around 540 Hz look to me like floor bounce artifacts (perhaps modified by the ceiling bounce) and imo should NOT be EQ'd away.  

Duke
hilde45's avatar
hilde45 OP
4,983 posts
 
Been testing all day, off the computer. I've definitely improved things a lot with systematic adding in of each sub and then doubling the amount of treatment at ceiling first reflection points. I'm now dialing in a variety of room treatments. Be back when I can.
erik_squires
16,195 posts
 
+1 on ceiling treatments, often overlooked.
Ag insider logo xs@2x
soundsspectacular
15 posts
 
MiniDSP 2 x 4 HD, a calibrated mic ( Umik-1 or Dayton ), a db measurement tool of your choice ( decibel: db sound level app on iPhone is great ), REW app on your laptop, YouTube tutorial Episode 7 from "Hometheatergurus" channel ( along with the gain matching episode )  and you will get absolutely amazing results if your willing to go through the headaches of a learning curve. 
I have a Focal 1000F, Def Tech SC4000 and an old Def Tech SC-1
 ( how's that for a crazy ridiculous mix?!! ) and it literally sounds like I have a single subwoofer from the main listening position. The SC4000 is only about 5-6 feet behind the listening position so occasionally ( but rarely ) I have to adjust the volume but it has remote control and through my Harmony hub it's easy as pie to do.
  MiniDSP allows for 4 configurations ( again controlled through the Harmony hub ) that I have set from flat response to a couple of different mid bump options to play with depending on the movie or music track and my listening whim at the moment. 
  A long time issue I've dealt with from just one to two to three sub configuration is now a mute point. Although nothing is perfect, the technology available is a wonderful tool if your willing to give it a try. I guarantee it's better than any " by ear " method, I don't care how good your ear is or how long you crawl around your room. Your just finding bumps in frequency at different areas of your room and not flat response anyway . There are too many factors so let technology be your friend. You ( and your ears ) will be glad you did.

P.S. - room treatments would be a great addition to the equation. That will
         be my next step hopefully.
hilde45's avatar
hilde45 OP
4,983 posts
 
Update. After a lot of work yesterday, I’ve made good progress. I have no peaks over 4 db, and 4 nulls that are -5-6db and one big narrow one that is -8 db.

Scan results are on my system page:

https://systems.audiogon.com/systems/9064/edit

Basics of what I did:
  • Started with a baseline scan. No subs.
  • Assuming positions I had worked out before were adequate....
  • Added 1 sub (REL). Adjusted in minute increments to (a) gain, (b) crossover, (c) phase -180 or 0.
  • Added subs 2 and 3 (Rythmik). Adjusted in minute increments to (a) gain, (b) crossover, (c) phase, (d) various filter adjustments on sub
  • Once those measurements were all optimized I adjusted:
  • Front wall treatments, adding, subtracting, and moving.
  • Side and other area treatments, same.
  • Ceiling treatments -- doubled and adjusted position of existing treatments.

REW notes: Besides using REW to play sweeps and analyze the curves I tried something new (for me).
  • I looked at the graph to identify the frequency where a peak or deep null was.
  • Then, I’d play a constant tone and move a single treatment, facing the laptop screen display of the SPL meter, keeping an eye on the tone and an SPL graph next to it.
  • When the the SPL graph showed a real decrease in a peak (or rise in a null), I’d leave the treatment there and then go back and do a sweep.
  • Then, I’d repeat it and either shift treatment position or add more treatment there or nearby.
By doing this for the most problematic peaks and nulls, I was able to try new and more asymmetric combinations of treatment positions to really address the curve. In other words, I finally discarded my visual bias.
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