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SUPPORT FORUMS FOR DECWARE SPEAKER PLANS >> Housewrecker Support Forum >> Scaling the HWK for 18"
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Message started by morpheous85 on 09/12/07 at 21:14:33

Title: Scaling the HWK for 18"
Post by morpheous85 on 09/12/07 at 21:14:33

I know this has been asked on here many times, but it seems the old threads are gone. :'( Also, I just bought the new plans, which have no specific info on scaling. Is it that you multiply everything by 1.2? (15 x 1.2 = 18)

Jason

Title: Re: Scaling the HWK for 18"
Post by asiquis on 09/12/07 at 23:22:02

send me an email I have what you are asking

better not to post the numbers

Ray

Title: Re: Scaling the HWK for 18"
Post by morpheous85 on 09/13/07 at 15:32:50

How about a PM? My e-mail is unreliable at times.

Jason

Title: Re: Scaling the HWK for 18"
Post by FlipC on 09/17/07 at 10:00:41

I'm interested in this also (PM'd but no repsonse)

Now my drivers are so old I can't find specs
for them and am to lazy to test them to find out. Since I'm scaling up to 18's I decided to use the drivers current cabinets (Cerwin Vega B36) rear chamber size (cubic feet) and adjust the center chamber to be close to that. Plus I have to take into account the width of the drivers which will change the width and depth of the over all design. Which since the B-26 cabs (these are THE OG ones) are 4.583 cubic feet I came up with 16x22x22 = 4.482 cubic feet.
Using Jason's idea of designx1.2 we get:
15.6x22.2x22.2 = 4.45 cubic feet center chamber
19.2x22.2x22.2 = 5.476 cubic feet top/bottom chamber

So that proves it is logical.
Though if you have your speakers specs you should use something like WinISD to model your driver in a single 4th order enclosure and double it. This doesn't take into account the off phase top port though.
(About to create a new post about that)

How about some input from the old plans
on how they say to go about scaling.

Title: Re: Scaling the HWK for 18"
Post by asiquis on 09/20/07 at 03:43:14

Flip

I PM'd you, but you have not opened the file yet according to my outbox....... :-?

Ray

Title: Re: Scaling the HWK for 18"
Post by FlipC on 09/21/07 at 07:21:16

Thanks for replying.
I already cut wood though. Ended up going with my original plan of using the B-36 enclosure volume as a base. Which makes the overall OD 57x33.5. My 2 lower ports will be 4" but are tunable with adjustable length. The top is a 6x6. It is going to be relocated due to end usage of cabinet. (PA)

All in all my numbers roughly match the ones you sent
and also morpheous85 formula so I am pretty confident it will turn out well.

I start on it today.
Will be taking pics and psot at end.

Title: Re: Scaling the HWK for 18"
Post by jearhart on 09/26/07 at 19:15:35

asiquis wrote on 09/12/07 at 23:22:02:

send me an email I have what you are asking

better not to post the numbers

Ray

could i get that also?

Title: Re: Scaling the HWK for 18"
Post by masseysmusic on 02/10/08 at 13:49:30

I too am going to scale my hwk for 18" also any advice in using these cabinets in a large portable P.A. would be greatly appreciated.

Thanks ahead of time.

Rick

Title: Re: Scaling the HWK for 18"
Post by Audiogasm on 08/09/08 at 18:47:03

I also need to scale for an 18 but can't pm until I make 5 posts

Title: Re: Scaling the HWK for 18"
Post by Audiogasm on 08/09/08 at 18:47:26

hmmmm

Title: Re: Scaling the HWK for 18"
Post by Audiogasm on 08/09/08 at 18:48:13

I'm ready to go get wood for this next week

Title: Re: Scaling the HWK for 18"
Post by Audiogasm on 08/09/08 at 18:48:48

and now I can pm

Title: Re: Scaling the HWK for 18"
Post by doctor_zivago on 09/12/08 at 12:12:21

I also want to scaling the HWK for 18" !

Title: Re: Scaling the HWK for 18"
Post by doctor_zivago on 09/13/08 at 02:35:42

I also want to scaling the HWK for 18" !
this is 2 nd post

Title: Re: Scaling the HWK for 18"
Post by doctor_zivago on 09/13/08 at 02:38:45

I also want to scaling the HWK for 18" !

Title: Re: Scaling the HWK for 18"
Post by doctor_zivago on 09/13/08 at 03:01:42

I also want to scaling the HWK for 18" !
I can PM now!

Title: Re: Scaling the HWK for 18"
Post by kaney16 on 08/30/10 at 03:27:10

Title: Re: Scaling the HWK for 18"
Post by kaney16 on 08/30/10 at 03:27:36

Title: Re: Scaling the HWK for 18"
Post by kaney16 on 08/30/10 at 03:28:02

Title: Re: Scaling the HWK for 18"
Post by kaney16 on 08/30/10 at 03:28:29

Title: Re: Scaling the HWK for 18"
Post by kaney16 on 08/30/10 at 03:28:53

Title: Re: Scaling the HWK for 18"
Post by gildcm on 08/30/10 at 16:34:21

If you are looking for the measurements to scale the HWK to 18's, I'm sure Steve still has the measurements. I have them but because they are Steve's plans he has to give the ok to share with you if you have purchased the plans. That is why I say ask Steve for the measurements to scale the HWK.

Title: Re: Scaling the HWK for 18"
Post by kaney16 on 09/13/10 at 09:04:54

aight so u do times dimensions by 1.2 but do u do that with the ports also?

Title: Re: Scaling the HWK for 18"
Post by DirtDawg on 09/14/10 at 16:31:28

I would say that I do not remember that anyone has tried your specific driver, but that is the beauty of this type of enclosure, especially in the way Steve has designed it.

Most drivers with a strong motor assembly will do OK.

Build it, test it, report back.

Title: Re: Scaling the HWK for 18"
Post by ArchmasterDragon on 01/23/12 at 07:28:36

Greetings!
I just bought HWK15 plans and I was planning to use 18" drivers, also what could be a good way to load the HWK ? In the info it says the ultimate way to load is using 4 drivers, but even good results are promised with only 1x15" driver.

How much the design can forgive in the dimensions ? I have to change the imperial measures to metric, because the local wood shop have cnc-machines that only accept metric input.

Thank you in advance

Title: Re: Scaling the HWK for 18"
Post by ZYGI on 01/24/12 at 01:25:49

I've scaled it these two ways, and liked the second version better than the first.....

First way is to multiply the width depth and height by 1.2 keeping the port sizes the same as the 15" version.

Second way was to multiply just the width and depth by 1.2 and keep the original height, and ports the same is the 15" version. But this would all make a difference as to what driver you are using.

Then convert it to MM and cut away....

Zygi

Title: Re: Scaling the HWK for 18"
Post by ArchmasterDragon on 01/24/12 at 01:35:08

Great, thank you for the tip. I was thinking that maybe I would use IST UXL-18" driver. I kinda thought that you need every dimension multiplied by 1.2, although rarely any subwoofer box can be modified like this, because everything affects everything, like driver, dimensions, are you using wool inside a box, how long reflex pipes are etc..

I think I'll follow the advice and do the second. Also what can you say about how many drivers would be "ok", I mean that is overkill even with 1x18" driver, but what is your opinion. 1,2 or 4 drivers in same box. the isobaric configuration drops the sensitivity by -3db per pair, so 2x isobaric means -6db lower sensitivity, I hope I wrote this correctly.

Thanks

Title: Re: Scaling the HWK for 18"
Post by ZYGI on 01/24/12 at 12:31:30

Yes, you wrote it correctly.

We tried a set of Dayton 15's, they worked best with one driver mounted on each of the internal baffles, clam shelled facing each other. We also used some McCauley 15's which worked best clam shelled on the baffle closest to the two 4" ports which gave a hump in response, at exactly where we wanted the hump.

So I guess simply put, if you want to go isobaric, you will have to find what is right for the drivers and what you are looking for.

Zygi

Title: Re: Scaling the HWK for 18"
Post by ArchmasterDragon on 01/24/12 at 13:15:43

Thanks for the tip. I'm just searching for a powerful and low bass with good punch, I have made a subwoofer with normal enclosure and even it goes to 30Hz, but I still feel lack of good kick. I was thinking how the 4 drivers affect the overall performance, because even though there are 4 drivers pumping air, but it's not a guarantee that it would work better than with 1 driver.

Title: Re: Scaling the HWK for 18"
Post by ArchmasterDragon on 01/27/12 at 11:44:45

I forgot to ask about the material thickness when scaling the HWK for 18", do you use the 3/4" material or do you multiply that also with 1.2 or just use 1" thick material. I think there is going to be more pressure in the box with the 18" drivers that is capable moving larger volume of air than with 15"? What would you recommend for suitable construction material, I was thinking to use MDF, because it's more dense and less prone to resonate?

Thanks