SUPPORT FORUMS FOR DECWARE SPEAKER PLANS >> Housewrecker Support Forum >> My Modded HWK

Message started by Valiant on 02/12/08 at 04:04:30

Title: My Modded HWK
Post by Valiant on 02/12/08 at 04:04:30

Let me begin by saying, what we have here is not exactly a House Wrecker,
though the principles and inspiration come straight from this site. What I
needed was a subwoofer to add to my surround system, and from what I had
read, the HWK seemed to be the best option.

The coffee table has been around for a while. I initially built it as a sub
several years ago and having two KEF 139B's, I popped them in either end
and waited for the magic to happen. And waited. And waited. Of course
that was before I had even heard of Decware and realised that here, we had
access to some great, pro grade products that could be easily built, cheaply.

So it was a case of retro fitting the coffee table, gutting it and starting again.
Purchasing 12" drivers fairly cheap was a bonus. Only problem, the coffee
table sound box is only 10.5" high. Inclining the speaker baffles, is an unusual
solution that seems to work. The internal dimensions of the box are
10.5 X 19.5X 45 inches. The weight is 56kg.

The drivers are Sony Xplod, 12", wired in series, so as to present an 8 Ohm
impedence to the Amp.

I downsized the ports, (basic ratio 12/15 X's the plans etc) and have yet to fit
a port extension on the main port, still on the lookout for one.

Very impressive results so far, especially when you perch your legs up on the
table whilst watching a dynamic sounding movie. Thunderbolts crack through
your feet. And I have yet to sort out a proper subwoofer controller for it.



Title: Re: My Modded HWK
Post by ZYGI on 02/13/08 at 04:41:47


 In your picture, top left corner, it looks like something is lying on its side, if that's the case you're listening to loud!!!!!

By the way, you don't have to make the top port round, just figure the surface area of the diameter port you need and build a square port the same length as the round port would have been with the same area. mount the port to the underside and flush trim the square to match the port.

 Looks good by the way. Someone, recently sent me a picture of there WO-32 made into a coffee table with legs and all, it was beautiful.


Title: Re: My Modded HWK
Post by Valiant on 02/13/08 at 05:02:03

Hey Bob,
Will finish the Coffee Table soon enough. Just a few trimmings needed to get
it back upto scratch. Pity I have to run a cable across the floor, but it's
terminated on the box with some gold plate terminals and I just unplug
the CTHWK when not in use.
Here's another pic...

Title: Re: My Modded HWK
Post by Valiant on 02/21/08 at 02:26:21

Just done a few tests on the CTHWK. 'Hear' are a few impressions...

Using a test disc that has has tracks of discrete frequencies, I compared the
sound difference at the top port with and without an insert. The top port is
5" in diameter, the insert is an old can of baby milk powder, snug fit and
6.5" long.

Starting at 20 Htz and going up, in all cases the quality of sound and the volume
was greater without using the can insert. With the insert in place, the CTHWK
seemed to be huffing and puffing. The same effect remained when I sealed
one of the bottom ports (~3" diameter).

The volume started taking a big dip around 1000 Htz, still a faint squeak
at 10000 Htz, but beyond that, nothing.

I guess the end result is I will be operating the CTHWK without the insert. I
could try and enlarge the ports to plan, but I think I may have hit on a good
compromise here and will sit on it for a while - gives good massages too  :)

I have yet to give it a good caning, things may change when I wind up the wick.



Title: Re: My Modded HWK
Post by Valiant on 03/04/08 at 06:21:31

Oh, and here is a rough sketch of the internal
layout for the CTHWK. Both drivers face towards
the large opening. The volume of the 'top' chamber
is slightly larger than the bottom.


Title: Re: My Modded HWK
Post by 60_and_up on 03/04/08 at 15:47:50

excellent idea, excellent work. i agree you should live with it for a while b4 any more cutting. any pics of the internals?

any 'stuffing' in there? definately try the drivers mounted a different way in 3 months or so.


heres my latest ht sub,

Title: Re: My Modded HWK
Post by Valiant on 03/05/08 at 01:38:13

Dear 60, the renovation of the coffee table was done in such a rush and
in weather that would melt chocolate - thats cooking chocolate my man,
that I never took the time to take construction pics.

There is no stuffing or sound insulation internally. I've built large speakers
in the past, initially well lined and stuffed, but have found them to perform better,
the more stuffing I remove. That said, I may line the top chamber internally
with self adhesive foam rubber matting and see how things behave.

I would like to say I could pull the CTHWK apart and try redirecting the drivers,
but I can't, she's welded closed. It would be a major operation.

One thing I will do is fit and glue a thin sheet (2-3mm) of ply wood to both ends of
the box. The ends are a bit underdone, 18mm HD chip (gees, I've got loads of
that stuff), and after looking at the HWK plans, and seeing how the ends of my CT
thump about, I can see why Steve insists on using 2X layers of everything. Though
thin, the ply should stiffen things up a little.

Have checked out your 'Pipe Speaker', great work. I have an eight foot length
of heavy (irrigation type) PVC pipe in my back yard, 12" in diameter - no, I'm
not going to touch it for a while yet, then again I'm not going to throw it either. ;)



Title: Re: My Modded HWK
Post by Valiant on 04/30/08 at 15:16:07

Just finished putting together a Sub Woofer controller kit. Try this link...

and, it works. Just have to do some fine tuning and clean up a few hums,
but even at low volume, it sure sets the room humming. So now that my
Luxman LV-92 is bridged, it should be putting out around 140 W rms. Hell,
40 Watts was scary  ;D.

Will do some tests and send some pics of the controller. An interesting little



Title: Re: My Modded HWK
Post by Valiant on 05/09/08 at 13:39:47

Here's the little guy, basically a wooden box, the sub kit and a +/- 17 volt, centre tapped
power supply. Works a treat. :D

Title: Re: My Modded HWK
Post by Valiant on 06/07/08 at 05:34:12

And here at last is the finished product. Now, time to move on to
something else,

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