Yummy Tumult, Nasty Room

Discussion in 'Home Theater Projects' started by Nat Ward, Nov 17, 2003.

  1. Nat Ward

    Nat Ward Agent

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    Hi guys. I wrapped up try one of my Tumult project about two weeks ago and have been enjoying the fruits of my labor since. I've never used a router or biscuit cutter so I decided to try out a simple 2.5ft^3 sealed box since it would only cost about $25 in MDF. Everything ended up decent (much better than my previous car enclosures!), and after a little break in from the Kiega amp I can say I'm mighty impressed in sound quality and extension. A definate step up from my Paradigm PS1200 to say the least! Just to see if the frequency response would be different with the sealed enclosure versus my previous bandpass, I decided to run some sign waves. What I came up with is the same turd I had below. Values are corrected readings from the RS digital meter. The two humps match up with room lengths, with some terrible lulls. This won't be my final measurements (I'm going to build a PR'd box next weekend), but can a BFD fix this? I don't know the limitations, I guess I could throw some huge filters to knock out the peaks. The sub is currently in a corner, and due to the layout of my apartment (neighbors love me [​IMG]) I can't really move it. Just wanted to hear some opinions before I spent more money. Thanks!


    Hz dB
    2166
    2471.5
    2774.4
    3072.5
    3372.9
    3674.7
    3977.6
    4277.3
    4578
    4876.7
    5272.5
    5468.5
    5766.5
    6062.5
    6359.5
    6659.5
    6960.5
    7265.5
    7566.5
    7864.5
    8164.5
    8464.6
    8762.7
    9059.8
    9359.8
     
  2. Dan Pawlowski

    Dan Pawlowski Stunt Coordinator

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    I have tumult and BFD. My best results are to move the sub away from the corner and use bass traps. I have my sub fire up....aprox. 2 feet in the air and about 4 feet away from my longest dimension (17'). I also have 1 bass trap (a bookcase with a bag of insulation behind it) in the furthest corner.

    I would suggest that you place your sub to fire up (that should help tame your minor boost at 75Hz). And move your sub so it is about 3' from the center cone to the corner (it looks like your room has 12.5' dimension...maybe a cube??)....do you have room for a DIY bass trap??

    hope this is helpful
     
  3. Wayne A. Pflughaupt

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    Wayne
    Nat,

    I’ve followed dozens of BFD equalizing threads on this forum over the years, and from what I’ve seen the BFD can “fix” just about anything except a true null.

    You might want to boost the signal level when you do your readings. When levels are in the low-60dB range and below, you run the risk of ambient noises polluting the readings (air conditioners, traffic etc.).

    Regards,
    Wayne A. Pflughaupt
     
  4. Greg Yeatts

    Greg Yeatts Second Unit

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    Make sure the crossover on the Keiga is at its maximum setting. The cascading of the Keiga crossover and your receivers crossover may cause some of the drop off at higher frequencies (as will the inductance of the voicecoil).

    This is very acceptable response from a sealed box. Do you have the Keiga with the 5db bass boost with an Fc of 25 hertz? If so, you may want to engage the boost and see how it measures. This will eat into your amps headroom.
     
  5. Nat Ward

    Nat Ward Agent

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    Thanks for the replies guys. I'm tight on placement, but I can try one more spot for grins. Bass traps will have to wait for now, I hope to be in this apartment for only a few more months and then move on so I don't want to build something just for here. Some day when I've got a great room for all my stuff I'll get around to that, but for now I think I'll try the BFD.

    Wayne, thanks for the tip on turning the volume up a bit, I didn't want to "torture" the Tumult with sine waves at high volume. I'll turn it up a bit and see what happens.

    Greg, I double checked to make sure my crossover was turned all the way up, I'm ok there. I didn't like the idea of running the bass boost since it reminds me of the "Loud" buton on car stereos, but maybe I'll give that a try. The volumes I'm playing at right now are low enough that this shouldn't suck too much power from the amp.

    I guess it's on to a BFD. One more thing to add to my rack [​IMG]. Now I'll have to go back and research. Thanks!
    Nat
     

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