First Home DIY Subwoofer - questions (1 Viewer)

[Bob Huskison]

I've looked at the Dayton, model pretty well - sealed or vented. I'm just not sure of the difference in quality.

 

[Bob Huskison]

All this driver diversion is moot now - I have an AV15 on the way now. Thanks Chris.

 

[Bob Huskison]

UPDATE:

It has been slow going so far - I've been busy at work, we've had a ton of company over on weekends, I burned up my plunge router - but I have made some progress:
* All the outer panels have been cut,
* My amp (HS500) was ordered over the weekend and Kyle should be shipping tomorrow.
* The holes for the driver and port have been cut, and
* The baffle has been glued together. (Just removed the clamps tonight when I got home from work.)

This coming weekend I should be able to:
* Cut hole for amp,
* Glue up remainder of box, and
* Test.

 

[Bob Huskison]

Received amp - thanks Kyle!

I have a question regarding the holes that go in the bracing: does it matter how big they are?

As my plunge router died, I am either going to have to cut out with jigsaw, use fixed router & drill "pilot" hole, or use a hole saw. I'm not sure if it makes a difference or not.

Thanks.

 

[Bob Huskison]

Well I completed the "skeleton" of the box (as I will still have to cover it in poplar to finish it) and was able to play with it a bit last night.

It was downright scary in a few places with the explosions in Pearl Harbor!! Plus, I found a whole bunch of frequencies where stuff rattles.:frowning:

Today I am going to fine tune the port length and then plot the sub's response. I've downloaded the test tones last night, burned them to disk, and went through the testing procedure to determine where the current tuning is. It seemed it was between two test frequencies (22.4 & 23.7), so I'm guessing it is approx. 1/2-way inbetween the two at ~22.8. The box spec'd out to tune to 24.5, so I'm about 2Hz off. Time to cut an inch, then test again.

Anyway, so far so good. I only wish I had a copy of BHD to play with today.

 

[Bob Huskison]

FINALLY FINISHED!!!

The hardwood has been glued on, sanded, stained, finished, etc. Put the sub and amp back in last night and we're good to go.

Final specs:
4 f^3
4" flared port - box tuned to 23.5 Hz (was modeled to be 24.5 Hz)
I've added 2lbs of poly to increase the apparent size of the box to match the tuning.
amp is Hypex HS500 (720W)
HP is at 150 Hz now (haven't played with Avia yet)
and EQ at 50 Hz and ~ +1 dB.

Plays really well, it really is scary.

There is one exception though. Ch. 22 of Pearl Harbor - where the Japanese attack - and specifically when the Arizona explodes the sub sub pops at higher levels (reminds me of when you get a free game on a pinball machine). I'm guessing it is bottoming, though it shouldn't be according to my modeling.

Will changing the tuning w/ the port help?
Do I need a BFD?

I do know I need HELP.

TIA

 

[Chris Tsutsui]

Did you make sure that the seal between the driver and the box is air tight? I used caulk on mine and it fixed some distortion noises.

Internal wiring not touching the cone, or slapping.

I'd make sure the subwoofer is calibrated with AVIA to the right level and that the crossover setting for the sub is correct at like 80hz or whatever you'll be using.

Is the sub corner placed so it doesn't have to work so hard?

If the "bottoming" out still occurs, Maybe you have too large of a room to fill with deep base from one av15 and should thinking about dual subs.

Other things to try... More stuffing, a lower tuning frequency, and could even try plugging the port with a household object like a nerf football to see if it bottom when plugged.

Good luck

 

[Bob Huskison]

Yes, I have a double seal of caulk on the sub (and at the amp too.)

The wiring shouldn't be long enough to touch the cone, but I'll check it out. I guess how persistent this would show up would depend on just how much too long the wiring was.

Will be doing AVIA this weekend...

Sub is corner loaded.

The room is a Living Room / Kitchen and measures 15x28x8. There seems to be more than enough bass at even moderate levels. (Again, I think AVIA will help here as I'll know for sure where "reference" is.)

I do have another half bag of stuffing I can throw in; as well as another 4" flared port I already picked up in case I needed it. If I were going to tune lower, how much? 20 Hz?

Also, I estimated the net volume of the box to be 4 f^3, but I wonder if I ended up more than that. I have the driver at .459 f^3, the port at .034 f^3, the amp at .187 f^3, the braces at .251 f^3 for a gross volume of 4.931 f^3.