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Top port noise? (Read 6266 times)
Wreckinthehouse
Ex Member



Re: Top port noise?
Reply #15 - 03/10/06 at 00:11:39
 
The ringing that I mentioned is a trade off that you have to deal with when using plywood. I would rather use MDF but because of the weight, the plywood is the way to go. This ringing is the reason that you wont find any serious car enthusiast's using plywood. I suppose if you can afford top dollar 13 ply plywood that you nay not have this problem, but i find that the foam on the inside of the lid does the trick.
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gexter
Ex Member



Re: Top port noise?
Reply #16 - 03/10/06 at 01:58:26
 
use something like dynamat on the sides and the basket. this helps the ringing.

The multiple layer ply is better but stuff like baltic birch even in a 5 or 6 ply is better than fir or spruce.

IMHO

PS glad you got the Port thing worked out..    did the dimensions of the port change from the original?... I was wondering if it was the port itself.  
because it was adjustable I was wondering if it was that design that was the problem.

the port design of the HWK is generic but TS parameters are unique to the driver creating problems with some drivers and not others.
I swapped four types of 8" drivers in a HWK for fun because my original had port noise. the result was the drivers made a differance.




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Bob
Ex Member



Re: Top port noise?
Reply #17 - 03/10/06 at 12:18:43
 
Wreckinthehouse, I actually used particle board (3/4") not quite MDF, but I would think better than plywood acustially, maybe? Weight isn't so much of a concern for me since once placement is set, weights not a factor anymore. Correct me if I'm wrong, but I thought weight, mass, ridgidity, strenth were all desireable traights {sp}. And an extra 50lbs would be a good thing? (other than the obvious problem of assembling the heavy monster.)

As far as material on the inside, I work at a Chevrolet dealership in the service department. We have automotive carpet padding in bulk rolls. Looks like like Dynamat, would this be a good thing to line the inside of upper and lower chambers with?

Bob
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DirtDawg
Ex Member



Re: Top port noise?
Reply #18 - 03/10/06 at 13:05:49
 
I built an 8" HWK for some "cast off" drivers I had laying around and I used MDF, followed the instructions to the letter, except I flared the ports to start with and it sounded really good as a bedroom sub, very low power use.

Recently, I gave it to a friend who has a lead foot as far as the power goes and there were some resonance issues. I helped him sort it all out, by using Dynamat inside the top and bottom covers, along with incorporating the "BOB JOB" inside the iso chamber.

There was still some panel flex (MDF and partical board are known for ballooning under pressure) and his WAF was not a positive number, so he skinned it with a 1/4" oak face plywood and some trim pieces, thinking it might help the flexion, slightly, but it would balance the WAF equation. Again I helped out and instead of lightly tacking the skin, which he wanted to do quickly to appease her, I used a half a bottle of glue and made it ONE PIECE ... 3/4" MDF + 1/4" plywood. I knew the 1/4" would add some rigidity, but I did not understand how drastically the thin skin would help to stop the flex.

This baby HWK is now solid and sounds very defined and nonresonant. I doubt if the 1/4" material would have the same ability with the larger cab, but you might try some 1/2" glued on well, if panel flex is a problem. It makes it look really nice, too. Grin
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HT-EXT
Ex Member



Re: Top port noise?
Reply #19 - 03/10/06 at 13:17:47
 
Thanks for the reply GEX. The HWK10 used a 4" x 7"(from flare lip to flare lip) but I took two flared ports and made one. The 4" x 8" was only about inch or so away from the speaker magnet(quad loaded). It worked o.k. but the 4" x 7" seem to accept more power and clearence was not an issue. The HWK12 has also workout successfully and it took the standard 4" x 7" without any trouble. The HWK12 likes about 300w+ and has no problem putting out 120db. Just for the record the HWK12 is loaded with KICKER COMPS and it is BADA--! Both HWKs workout great and I am very THANKFUL for all the HELP, INFO, and PATIENCE.      HT-EXT
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Bob
Ex Member



Re: Top port noise?
Reply #20 - 03/10/06 at 13:52:26
 
Thanks Dawg for naming something after me (Assume it's me?) Did you install the mat only on the inside of the 'caps'. Not on the walls?

Thought about an exterior "dressing" (won't call it cosmetics anymore, I got flak over putting makeup on my sub) on it to increase the WAF. Was thinking it may increase the ridgidity also.

Bob
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Adrian D.
Ex Member



Re: Top port noise?
Reply #21 - 03/10/06 at 16:02:05
 
i hate particle board but i actually have all my speakers made out of that stuff  :'(
maybe that's why i ended up hating it.
if i put my phone (even a remote) on the top lid of my db-10 and it gets +150w, the phone vibrates like crazy. ugyl panel flex  :'(
i can actually feel the lid flex when it hits those low-lows.
i'm planning on building one out of 1inch mdf  :-* hoping that flexing will go away.
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Bob
Ex Member



Re: Top port noise?
Reply #22 - 03/10/06 at 17:20:49
 
How about some tasteful exterior bracing?
Bob
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Wreckinthehouse
Ex Member



Re: Top port noise?
Reply #23 - 03/11/06 at 01:26:22
 
Hey Adrian D.,
        I also thought that the top panel was flexing, but upon further inspection, it was actually the whole Housewrecker bouncing around on the floor. Make sure that this is not the case before you go through a lot of trouble. I lay mine sideways when DJing and the problem is solved.
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60ndown
Ex Member



Re: Top port noise?
Reply #24 - 03/13/06 at 14:19:31
 
[quote author=Wreckinthehouse  link=1141303128/15#23 date=1142040382]Hey Adrian D.,

  I also thought that the top panel was flexing, but upon further inspection, it was actually the whole Housewrecker bouncing around on the floor. Make sure that this is not the case before you go through a lot of trouble. I lay mine sideways when DJing and the problem is solved. [/quote]

man, my hwk 15 weighs about 150 lbs, yours bounces around dureing playback?? you mush have some SERIOUS power going to it  ;D Cheesy
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Adrian D.
Ex Member



Re: Top port noise?
Reply #25 - 03/13/06 at 15:18:11
 
no tasteful exterior bracing, because i bought the particle board pre'finished.
no, the box isn't bouncing on the floor. i'm 90% sure it's top lid flex.
i wonder how much that 1 inch mdf wo weighes ??? i wonder how much my 1 inch db-10 will weigh  ???
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Bob
Ex Member



Re: Top port noise?
Reply #26 - 03/13/06 at 16:10:59
 
Close to what you do...

Bob
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Wreckinthehouse
Ex Member



Re: Top port noise?
Reply #27 - 03/14/06 at 23:07:49
 
Hey Adrian,
      Your top and bottom lids are double thick, right?
60NDOWN,
       A Peavey PV-2600 Powers my 2 Housewreckers. 1300 watts per HW.
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