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SUPPORT FORUMS FOR DECWARE SPEAKER PLANS >> Deathbox Support Forum >> Are there plans or does anybody have experience...
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Message started by cubdenno on 02/18/08 at 04:09:41

Title: Are there plans or does anybody have experience...
Post by cubdenno on 02/18/08 at 04:09:41

Using a single 15" driver in a deathbox?

I already own the sub and don't want to spend any money on more drivers. This is for a car SQL application.

Title: Re: Are there plans or does anybody have experienc
Post by Bart_West-VL. on 02/18/08 at 09:27:22

No experience but it crossed my mind a few times and I would multiply all the dimensions by 1.5
On the other hand I think the tuning will not work this way.
Only Steve could answer this one.

Bart

Title: Re: Are there plans or does anybody have experienc
Post by musgofasa on 02/18/08 at 15:17:37

I have scaled up the design for 15s several times.

It can work, but I don't think the scaling up by 1.5 works. When we did it, the sound was decent, but not close to the 10" version. SPL was a bit weak when we got SQ out of the box.

My recommendation would be to design a 4th order BP specifically for your driver.

It might be that your driver would work well in a scaled up DB.

What driver do you have and what vehicle is it going in to?

take care,
Robert

Title: Re: Are there plans or does anybody have experienc
Post by cubdenno on 02/19/08 at 00:27:03

Thanks for the responses so far. I am using a TC Sounds TC3000 15" DVC. Currently its in a 3.6 cubic foot poted enclosure tuned to 35 hertz. It plays quite loud and sounds fantastic on rock. Decent on my son's rap/hip hop. I am just looking for other box designs that will show off this sub.

Title: Re: Are there plans or does anybody have experienc
Post by brian84corvette on 02/19/08 at 10:14:08

if im correct that specific sub you mention has a whole lot of travel in it, meaning it will move tons of air, it would be a shame to put it in a sealed box since it would psyicly limit the travel of the suspension by the compressed air on the sealed side,.....

id look in to a angled down fire type box,
with a L port in it - like I made for my 18" jbl.

Title: Re: Are there plans or does anybody have experienc
Post by musgofasa on 02/19/08 at 15:29:48

I will have to pull some specs on that sub, but it seems like a 5+ cu ft enclosure tuned around 30hz worked really well. Big port in a big box.

Haven't tried one of those in a down firing yet. Sounds like a good idea though.

What vehicle?

Take care,
Robert

Title: Re: Are there plans or does anybody have experienc
Post by Adrian on 02/21/08 at 12:15:47

cubdenno wrote on 02/19/08 at 00:27:03:

Tune it lower or seal it :)

Title: Re: Are there plans or does anybody have experienc
Post by brian84corvette on 02/21/08 at 14:46:40

my jbl 18" is in the back of my corvette !

please excuse my wiring nightmare. hahahaha.

Title: Re: Are there plans or does anybody have experienc
Post by brian84corvette on 02/21/08 at 14:51:16

correct me if im wrong - but is the house wrecker a design specificly for 15" subs, and is ported on both top and bottom?
that should suit the TC sounds 15 nicely I think.
it would just require something huge like a suburban or work van to make it sound good in the viechle, - side benifit - it will also sound amazing in your house !

Title: Re: Are there plans or does anybody have experienc
Post by Bart_West-VL. on 02/21/08 at 22:05:27

The Housewrecker IS meant to be used in the house, not the car!

Title: Re: Are there plans or does anybody have experienc
Post by cubdenno on 02/22/08 at 04:27:07

Right now it is sitting in a Toyota Solara. Fairly small cabin for a coupe. The box is slot ported. It does have a god awful amount of travel something close to 3" 's if memory serves. I modeled a small sealed at 1.75 cubic feet and with a 2 db bump at 30 hz should almost be flat to 20 hz. Of course I lose some efficiency but my trunk would be free of some box. The problem with sealed is the amount of cone excursion I run into at the lower end of frequencies where the ported i can somewhat control the excursion.

Title: Re: Are there plans or does anybody have experienc
Post by Bart_West-VL. on 02/22/08 at 09:55:46

You might want to learn a bit more about speaker building first.
A closed box is best to control the excursion.
With a ported box, the excursion below the tuning frequency is way out of control!
So, you can get a vented box with a really low tuning, but not as efficient.
Or just use a sealed one, that's the best control you get and the simplest to calculate.

If you tune, lets say, at 40Hz in a vented box, you have minimal excursion at 40Hz with a maximum sound output.
If there's a thump at 30Hz, there will be no resistance from the box anymore, it's just an open hole in the box to that frequency. The result could be a lot of damage to the driver if that tune keeps on firing!
Also, that 30Hz won't be very audible as it's canceled out quite a bit.

This all sounds bad but it also depends on the car itself, so even riding with the window opened up an inch or two, can make a huge difference!

►Do some research.
Bart

Title: Re: Are there plans or does anybody have experienc
Post by musgofasa on 02/22/08 at 15:25:12

Considering the motor structure of that woofer and the suspension and the application:

I would load the specs into WInISD and design a box tuned to about 30hz. Make the box big enough that you can have a port that is roughly 1/2sd. The end result will be large and have a long (most likely L shaped) port.

The idea here is that the cabin gain will keep a good even response from tuning up to around 60+ hz and the motor structure will supply adequate strength for about an octave below tuning (15hz). There isn't enough content below that point to worry and you will probably not want to play too much that low in a car anyway.

The effect here is it will show off everything the woofer was designed to do. The huge excursion and strong motor will produce very high SPLs at tuning and close to it. It will also utilize cabin gain and tuning (harmonics closer to 60hz) to produce a level response as well as a high SPL throughout that band. At the very low frequencies, this driver won't break up until you reach really subsonic noises. You might want to have a 10 or 15hz high pass on it just to ensure that it gets less juice at those below-tuning freqs that cause problems.

It will take up a lot of real estate in that trunk though. If that is a big problem, sealed will be your safest bet, but if you were my customer, I would be suggesting the large ported box.

Let us know what you decide.

Take care,
Robert

Title: Re: Are there plans or does anybody have experienc
Post by cubdenno on 02/23/08 at 03:05:47

Thanks guys for the input. Just so you know I did use WinISD to model the current enclosure I am using. And sorry I did not clarify what I meant about excursion regarding sealed vs ported. I do use a subsonic filter (high pass at 31.5@24db/oct) just below my tuned frequency to protect the woofer. I get the loss of control under the tuning frequency. WinISD showed excursion reaching close to the limits. Near 22mm if memory served

Space is at a premium in my car. The trunk is a lot smaller than I guess I planned for. I want to say that my box does in fact sound great.It is well controlled and does in fact have gobs of output. I swear it knocked a kidney stone loose in a buddy of mine. I was just looking for other possible box designs.

Musgofasa, I went a bit higher tuning to get the increase (it had a slight bump in output over the flatter curve tuned to 30hz)in output and the smaller overall box design. Though it's pretty giant as it is. I used a double baffle and a big arse slotted port. Of course the port took up a huge portion of overall box volume. Thanks for the advice

I was incredibly impressed with how it sounds. I know I keep saying it but it is so musical. Dire Straits "so far away" is awe inspiring. The string bass in any of the Holly Cole Trio songs is simply amazing.

It makes me excited to get the rest of my system installed. Continue with the input advice. I really do value it. And I know I didn't mention it but thanks Bart

Title: Re: Are there plans or does anybody have experience...
Post by thecorrupterx on 04/30/09 at 14:55:39

Would it be possible to make a DB12 into a 15" version by multiplying one dimension by 1.25?
i.e. 14-> 17.5 and mounting the sub at an angle to make up for the width in the other direction, or does anyone think that the box would also have to be longer as well as wider in a single direction?
I am just wondering because I have a single 15" driver and I don't want to have to buy any new equipment.