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SUPPORT FORUMS FOR DECWARE SPEAKER PLANS >> Housewrecker Support Forum >> HWK from scraps? (new experiment)
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Message started by Jerry_Allen on 10/30/05 at 13:06:03

Title: HWK from scraps? (new experiment)
Post by Jerry_Allen on 10/30/05 at 13:06:03

I have some panels let over from another project.
48" x 17"

This would give a HWK that is 15% too small for 12" drivers and .05% too small for 10" drivers but I have some old 12" drivers that I can use for the initial experiment.

Can I expect anything acceptable from using 12" drivers in a cabinet that is 48" x 17" x 15.5"? The upper and lower chambers being 2.29 cu. ft. the center being 1.99 cu. ft.

Thanks

Title: Re: HWK from scraps? (new experiment)
Post by BigAir on 10/30/05 at 14:25:36

That's a pretty radical change from the original design, but it should still work if you are willing to figure out what the new port sizes would be. Just model the original HWK with 12's and then go for the same tuning with your new size. The center chamber will change things a bit, but you should be able to get close enough. I would make the center chamber just big enough to fit your drivers magnet to magnet if so desired. Otherwise, pony up the $20.00, buy another sheet and build it according to Steve's design.

Title: Re: HWK from scraps? (new experiment)
Post by gexter on 10/30/05 at 15:40:15

Sometimes it's all said in one post!
I do have a thought if you clamshelled the dirvers in one end. that would give it two unique sized volumes to work with.
But all the same proccess that big air is about.

I would do all the modelling that you can in differant configs

I'd do it! if you have room for a big box

Title: Re: HWK from scraps? (new experiment)
Post by Jerry_Allen on 10/31/05 at 17:08:16

I built the HWK12 box after I discovered that my scraps were too large, not too small, just cut some more off :)~

Sounds very good for being loaded with 2 shocked out _BAD_ parameter, junk 12" subs facing each other from each end. The high bass is too punchy, the low bass is mm mm good. This is the kind of bass that will drive a guy nuts, I need to remove the high end puch a bit.

Tuning question - Will making the lower ports longer or making both the lower and the upper chamber ported as the upper chamber (single 4x8 port) tune both ends of the cabinet lower?

Thanks!

Title: Re: HWK from scraps? (new experiment)
Post by 60ndown on 10/31/05 at 17:54:06

Jerry_Allen wrote on 10/31/05 at 17:08:16:

try both magnets in the sealed centre chamber.this allighnment seems to work best for most.

Title: Re: HWK from scraps? (new experiment)
Post by Jerry_Allen on 10/31/05 at 19:27:00

60ndown wrote on 10/31/05 at 17:54:06:

try both magnets in the sealed centre chamber.this allighnment seems to work best for most.

Still too much punch for my taste.... lay a pillow up against the lower ports and that is just about right.

I wish I understood bandpass tuning....

I replaced the 2 3.75 x .75 ports with a single 4 x 8, too far but it is _low. Guess I will cut off the new 4 x 8.

Thanks

Title: Re: HWK from scraps? (new experiment)
Post by stvcmty on 11/01/05 at 03:07:19

Lengthen the lower ports to lower their frequency. By lowering their frequency, you will get rid of some of the high bass that you don’t like since they control the upper end of the HW’s output.

Stv

Title: Re: HWK from scraps? (new experiment)
Post by Jerry_Allen on 11/01/05 at 04:21:25

stvcmty wrote on 11/01/05 at 03:07:19:

By lengthen, do I go into the cabinet with a tube or do I add depth on the ouside... not sure on this one since I do not understand bandpass

Thanks

Title: Re: HWK from scraps? (new experiment)
Post by stvcmty on 11/01/05 at 18:26:57

Either adding length into the cabinet, or adding length by having a tube stick out of the cabinet will work.

If the port tube goes into the cabinet, then it will displace volume from the chamber, raising the tuning frequency of the chamber but lowering the tuning of the port.

If the port comes out from the cabinet, the volume of the chamber will not change but the ports tuning will drop.

If your application will allow you to have the port tubes sticking out; that it the simplest solution.

Having the tubes inside will make the box look better, and will protect the tubes.

Looking at the volume of the chamber compared to the volume of the tubes you would likely use, having the tubes on the inside will not take up too much volume.

Since the box is built, the method that will give you the best results is to just play with different port lengths. Start with two 6” long port tubes, and see how that sounds. Then shorten them (both the same length at all times) until you find the sound that you like.

Stv

Title: Re: HWK from scraps? (new experiment)
Post by Jerry_Allen on 11/02/05 at 02:37:16

stvcmty,

Thanks for the guidance, since I had sealed the 3.75 ports, I just cut the 4x8 mounted between the 3.75 patches to 4x4, best of both worlds, it sounds and measures good with TrueRTA. My next HWK will have 2 ports this one is the experimental version I guess...

Jerry