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trex-btnhfan

Burping below tuning?

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I am burping my loudest freq below the tuning of the port. My only question is, how much lower should I tune the port to?

I burp the loudest at 47, port is tuned to 52

Would tuning it at 45 be okay?

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Tune to the frequency that the output will peak at... in most cases, if you need to burp at 47Hz, tune around 35-37Hz.

Are you sure you are tuned to 52Hz? That just seems so not right that you are loudest below tuning.

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Tune to the frequency that the output will peak at... in most cases, if you need to burp at 47Hz, tune around 35-37Hz.

Are you sure you are tuned to 52Hz? That just seems so not right that you are loudest below tuning.

Yea. Its very weird. My guess is that it has to do with box impedence?

Its weird because for everybox that I have built excpet for one, so like 5, my burping freq has always been at 46, which was the loudest, no matter what tuning the port was at.

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Its weird because for everybox that I have built excpet for one, so like 5, my burping freq has always been at 46, which was the loudest, no matter what tuning the port was at.

DING DING DING DING DING.

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Tune to the frequency that the output will peak at... in most cases, if you need to burp at 47Hz, tune around 35-37Hz.

^^^, but in all reality, need to model the response to tell you what frequency to shoot for. Then back it up with an impedance curve.

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alright, You say that 46 is the loudest so far? no matter what tuning? how about what box size....?

Box resonance has as much effect on note as port tuning & driver fs.

You want to change the note? change the box size.

You want to keep the note? tune lower, burp, trim .5" off the port length, burp, trim, burp, trim... Until You are continually losing dB's. Then, rebuild / replace the port to the loudest length.

I would work on port before port length though.

-Nick

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Once You have the box dialed in, get the impedance map around burping frequency. At THAT point, figure out what amps you need to drive the reactive load.

Do NOT go changing Your burp freq to try to take advantage of lower dcr ranges. You'll sacrifice Your note and make the chase for tenths that much harder. Once You have the box (version 80047.2 or whatever) dialed in, add power until You lose dB's.

At that point, start messing with the interior.

If You aren't happy, build a new box & start again.

Sorry.

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