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Discussion Starter #1
Heres what I have setup for my sub. I have an AA avalanche 15. I have it in a 10cuft box with a ~16hz tune. The port is a 6in diameter PVC pipe with a length of 2ft. I am powering the sub with a ep2500. The signal is coming from a denon 2809ci.

Now I currently have the ep2500 with the dial set at the 9o'clock position with the denon sub level down to -4. I know this does not mean much in regards to voltage settings. But I am having this nasty snap sound coming from the sub.

For example I was playing the last couple scenes in transformers where there is alot of stuff blowing up and whatnot. A couple of the scenes dig real deep. The bass is impressive but when it gets REAL deep, my sub makes this gut wretching SNAP sound. Not a bottoming out sound, but like you are snapping some thin wood. At which point I turn it all the way back down, and the sub operates normally.

I come from the 12volt world so I have had plenty of experience with subs, even blew my own once, so i know what bottoming out soudns like, but I have NEVER heard this sound before. On scenes with normal bass, I can turn the dial past 12 o'clock and at that point it will be substantial bass. But the only way I can safely eliminate that snapping sound is to turn the dial allll the way down. The dip switches are all set correctly except for the clip limiter(off), which I would assume would have no effect as it only limits the clipping on the amp side (correct me if im wrong).

I duplicated the sonotube designs from either this site or htguide, with exception i used a box instead of a sonotube, I have not heard of anyone having this problem before. Does anyone have any advice, the only thing I can think of is making a new box and bringing the tune up to 20hz.
 

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Discussion Starter #3
yeup, I was under the assumption they were all xbl2? they discontinued them in 06 i think. I mean to be hionest i did not give it the least bit of time to break in, but i doubt that would affect performance that much and cause that nasty sound.
 

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Discussion Starter #5
hmm, im not too familiar with filters. I was under the assumption a low pass filter woudl filter all the upper frequencys and play the higher ones. and a high pass would play all the upper and not play the lower. hahha i take that back makes plently of sense. now my question is, how do i implement this, or is this a setting ont he reciever?
 

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Discussion Starter #7
Fs 15.7 Hz
Qms 3.5
Qes .334
Qts .305
Vas 300.6 L
Re 3.2 ohms
Znom* 4 ohms
Xmax 27 mm
Sd 749 cm2
Mms 269 g
Vd 4.04 L
Pnom 800 watts
Le 2.4 mH
Cutout 14.125"
Diameter 15.5"
Depth 7.875"
Weight 37 pounds

here are the specs I have a bfd I have not used yet. Would that be able to create a high pass filter?
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That is a defiant clipping sound, You are probably clipping the input or the output of the amp. You should turn down the receivers sub output and try the scene again if its gone turn up the output of the amp to match the level you had before and see if it re appears. If it does then you know your clipping the output of the amp.
 

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Discussion Starter #11
Yes the ep2500 is in bridged mode. Would changing it to stereo have any effect? Also I have tried lowering the sub output on the reciever side, down to -4. I could try lower.
 

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Discussion Starter #13
Ok I will give that a try, but would you be able to explain a bit as to why that would determine the need for a HPF? I am assuming lower power would push the cone less?
 

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lower frequencies (below15Hz) require allot of power to make the cone move. It also requires the cone to move much more than playing higher frequencies. By putting a HPF on befor the amp you will not send any information below the HPF setting and thus dont over work the amp/sub.
 

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Discussion Starter #16
makes plenty of sense. I was messing around with ISD earlier and it looks just like what you have above? I tried it unbridged in stereo mode which would be ~650 or so watts. Although it did the popping less it still did it. So I've been looking high and low for a good hpf filter and it looks like the reckhorn b1 fits the bill. Correct me if im wrong but the b2 only has benefits if you want it to start rolling off at 10-12 hz. Does anyone know of any other alternatives. From my research I am under the assumption the BFD cannot do a hpf by effectively rolling it off.
 

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Discussion Starter #18
so a b1 would be sufficient for my use? I also have a BFD, Would adding this to the mix screw everything up?
 

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Discussion Starter #19
Also in the 12v world, I have been taught to NEVER use bass boost, is bass boost a different application in HT?
 
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