Any advice?

[logan00]

I recently purchased dual HO's and I am still playing with their placement. Currently I have them both up front spread apart as you can see in the attachment. My open basement space is about 6000 cubic feet with the theater taking up about 1/3 of that.

Please look at the attachments of my layout and frequency response and tell me what you think, all advice is appreciated.

The first graph my FR before eq and the second is after eq. Also, you will see that I have a nice hump below 20Hz, if anyone can tell me how I can eq that I would apprefuiate it, I am using REW and a BFD.

Love these subs by the way :D

[jmprader]

I have dual HO's and used a BFD with REW to eq as well. Very similar room gain peak under 20hz and it's difficult to get rid of.

Your overall result looks great. You have much flatter response elsewhere than I could get (a few nulls I cannot get rid of) in my room, so I am jealous, as many others should be out there.

You might be able to cut a db or two by experimenting with a couple of filters, say a deep cut at 20hz with a 24-28hz boost to try and keep your mid 20's at the right level. You might also get some relief moving the the HO's out into the room, though that did not help me much until they became obtrusive. Room treatments are pretty much out of the question, they can't impact FR that low.

Since, except for organ pedal and synth music, this is below the musical range, why worry? A little more subsonic emphasis added to HT material usually annoys only the neighbors!

[lradden]

I have a single HO w/turbo and have a bump from about 16-20Hz. Other than it's really flat. Heck if I didn't have the bump from 16-20Hz mine would be flat from 11Hz-80Hz. Not sure if I can do anything about the bump though. I'll post the graph when I get home.

[logan00]

I am going to play with placement some more tonight, I know that I have a dip around 40Hz if I have only one sub playing, having both playing smooth it out some. So if I can get rid of the dip at 40Hz that I get from just one sub playing then I should be able to increase the overall FR with both playing. Makes sense?

Hey lradden, this is Kevin12586 from AVS :)

[lradden]

Kevin, you madman with the duals, how the heck are you? I got home late last night so I forgot to post the graph. I'll post it tonight.

[Pete_Hsu]

Hi guys,

Can you all show me what your frequency response looks like when using turbocharger installed and 22Hz mode set on the amplifier? Thanks!

[logan00]

Sorry Peter, I didn't buy the turbo, only dual HO's :D

By the way, last night I played around to see if I could do anything with that drop around 40Hz and came up with the graph below. What I ended up doing is running one sub in max output and one in max extension.

Based on my updated graph Peter, what benefit do you believe I would receive by adding a turbo and/or an MBM? Looking at the graph, I have a dip from 40Hz - 60Hz, if I am not mistaken the MBM would only help me from 50Hz - 60Hz, correct? I am not sure where the turbo would help though.

lradden, looking forward to seeing your graphs :)

[Pete_Hsu]

Kevin, that looks pretty good from 16-40Hz, although there is no doubt that you would really benefit from an MBM-12 at some point in the future. The MBM-12 would significantly increase frequency response linearity and improve headroom in the 50-100Hz range.

What does your response look like when running both subs in maximum output mode? Also, where are you currently placing your subwoofers?

Note that you don't need turbocharger to run in overdamped mode as I had mentioned earlier. You can plug a port on the subwoofer, and run it in 22Hz mode on the amplifier, and you will have an overdamped response. Try running both subs with one port plugged on each of them, and 22Hz set on the amplifier.

If you could work up a quick sketch of your room and post it here, I would really appreciate it.

Thanks!

[lradden]

This is my response at 16Hz w/turbo from a month or so ago. I haven't taken the 22Hz measurements yet.

[Pete_Hsu]

Legairre, try two different measurements: one with the sub in 22Hz amp mode with both ports open and no turbo, and one with the sub in 22Hz amp mode with turbo installed. I am curious not only about the graphs, but about your subjective impressions. Thanks so much...

[logan00]

Peter, if you look at my first post there is an attachment of my basement plans showing where my subs are located and the basements dimensions. What benefit is there to running the subs in overdamped mode?

Also, I played around with a few settings in the receiver and this is now how my subs are eq'd.

Also, Peter what db do you believe my duals should reach before they start to compress? The reason I ask is that I watched a movie scene at -8 on my receiver and got 108db on the spl, I increased the receiver to -6 and still got 108db for the same scene, does this sound correct?

I will plot both subs in max output for you to see and I will look into running them overdamped and plot that as well.

[logan00]

Nice graph lradden, I am jealous :)

[lradden]

Nice graph lradden, I am jealous :)Thanks logan I use a BFD and moving the sub 3 or 4" close made a big difference in a dip I had at 30Hz. It seems I have the bump from around 12-20Hz, but I kind of like it.

Peter,
Sorry but we're doing some painting in the theater this weekend and all the furniture and everything is out of the room so I can't run any testing. I'm tempted to hook things back up but the my wife would kill me:) .

[logan00]

lradden can you help me with the input level of my bfd? Right now I am at -9.5 on my receiver, should I increase the bfd input or leave it where it is to get the most output volume from my subs? What is your input level set at on your receiver? I believe that my bfd is holding back my subs from outputing more spl that they are capable of.

Thanks

[lradden]

Logan I'd be happy to help. My input level is at -5, and input level will be different from room to room depending on room size and listioning position. You should set the receiver's input level with the BFD in "bypass" (no filters applied) using a movie with heavy bass and at the loudest volume you would listen. Once the input level is set leave it there and never touch it. Then put the BFD in active mode so it's using the filters and calibrate the sub using the sub's gain control.

Legairre

[logan00]

Thanks lradden, I FINALLY got my input level set correctly. :D