Advice on current setup and possibly a new one

Discussion in 'Home Theater Projects' started by Travis Destasio, May 21, 2003.

  1. Travis Destasio

    Travis Destasio Auditioning

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    I currently have a 10" B&W subwoofer which I am fairly satisfied with but I just can't seem to get it set-up right. When i run the test tones on Avia I get big dips in the frequency response(6 dbs or so), because of this and the need to always have bigger and better I have been considering a shiva or av-12 sub. Now I would like to keep it as small as possible but size isn't a major issue. The sub will be used 90% HT. Been considering a pr because i beleive they are smaller because of no need for a port. Was interested in opinions on the 2 drivers as well as what alignment you guys feel would be best. My room is 11'x18'with 8' ceilings and no major openings to other rooms. Any ideas on how to properly set-up my current sub until i can build a new one would be appreciated as well.
     
  2. Mike Keith

    Mike Keith Second Unit

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    Where (what frequency) are your dips and peaks at, the more information you give the better chance someone will be able to help. Sometimes the driver response is inadequate, but most of the time its the room or integration of the sub with the mains. The AV12 is a good driver, however chances are you will still have those dips and peaks until you find the cause.
     
  3. JoelTW

    JoelTW Stunt Coordinator

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    I don't think +/- 6 dB is bad if it's from your listening position...(in my opinion)...because I have trouble getting even +/- 10 :b

    I can't decide if I should use 2 subs, and maybe they would balance out better
     
  4. Travis Destasio

    Travis Destasio Auditioning

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    OK I ran the test tones and at 80 and 70 it's nearly flat at 60 it's at +6 db's and at 50 and 40 it is at -9 db's and then from 30 to 22 it is back to the calibrated level. I assume that the majority of the problem is my room but have no idea how to remedy this. I tried moving the sub up and down the wall but it made little difference. Any help is appreciated. Thanks
     
  5. Dave Milne

    Dave Milne Supporting Actor

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    Travis,
    There is no doubt that a well-designed AV-12 or Shiva would outperform your B&W (more output capability, less distortion, probably deeper extension). However, if you don't change placement, you will get the same room response.

    There are some on-line room response calculating tools. Try a search or perhaps someone here can point you to one. I just did a lot of trial and error - moving the sub and/or listening position until I got the best response. Small changes can indeed make huge differences. One trick is to place the sub in the listening position and move around the room to the point where the bass sounds the best - this is the best sub placement location.

    Finally, you can EQ out the peak at 60 with a BFD or similar. The hole at 40-50 is a problem - it will cause a substantial loss of bass "punch". In general moving the listening position back toward the rear wall often mitigates bass response "troughs".

    Do you have an extra power amp for a DIY sub? Or are you thinking plate amp?

    Have fun building and tweaking! School is out and heck... it's too hot and hazy to be outside anyway [​IMG]
     
  6. TimForman

    TimForman Supporting Actor

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    Most likely the problem is the room, not the sub. My room creates a dip at 55 Hz and a peak at 71 Hz. I added a BFD to my Sealed Tempest to flatten it out. I moved the Tempest to the front corner which helped considerably. This is great for music but I was still wanting for movies so I added a Shiva Sonosub to the back of the room, also EQ'd through the BFD. This seems to work well in my 3000 cu. ft. room.
     
  7. Travis Destasio

    Travis Destasio Auditioning

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    I will try moving the sub around some more tonight. Hopefully i can smooth it out at least a little. Dave, I was planning on using a plate amp. Fairly inexpensive and no more equipment to go in the rack. As far as school goes, I couldn't be happier that it is out for the summer. It will give me time to build some of those back lighted poster boxes I've been looking at. Tim, with the bfd were you able to flatten out the dip that you had as well or just the peak, I have no idea how these things work? This might be a final option for me. Thanks to all
     
  8. TimForman

    TimForman Supporting Actor

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    I was able to get the dip and the peak within 5 db of one another with the BFD. Without the BFD there is a 24 db difference. Once you get used to adjusting it the BFD is fairly easy to use. You have to enjoy experimenting with adjustments. It is far and away from plug and play.
     

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