12/26-27...24Hr. Sale on Dayton 12" DVC woofer at PE (1 Viewer)

[Jack Gilvey]

http://www.partsexpress.com/pe/pshow...=295-185&DID=7
Heads-up. A nice woofer at a nice price, $75.
Ends 12/27 at 6 P.M. EDT.

 

[JimPeitersen]

Jack,

What type of PR enclosure (size, tuning, etc.) would you rec. for this driver (using Adire or Styke PR's)? Thanks,

JP

 

[Jack Gilvey]

Hi Jim,
I use it sealed, but this driver looks like a lot of fun in a PR box as its fairly small box requirements really allow you to take advantage of a passive's strength (low tune in a small box).
A couple very different alignments which look good to me are 70 liters tuned to about 25Hz, this would give massive HT SPL from a 2.5ft.^3 box. Even if you tuned this one to 20Hz, room gain might counter the rolloff near 20Hz (or you could just ad some eq near Fb) for amazing performance from a very small box.
Another approaches an EBS curve, and it's 120 liters with an Fb of 18Hz. Very deep.
At $75 for the driver, and $50 for a B-stock Adire PR-15 , this might prove a little too tempting for me. And I can't catch up with projects I've got now.

 

[Ryan Schnacke]

I've got a brother-in-law who's wanting a sub in his Mustang. Seems like this drive could go in a small enough enclosure for a car.

I saw that this morning and couldn't believe my eyes! In terms of displacement/dollar this is actually a better deal than a Tempest or 15" DVC!

I'm using Unibox for the first time. I have no idea how to set Qa and Ql for a sealed box or Qa, Ql and Qp for a vented. Any help you can give me would be appreciated. But here's what I've found with this driver.

A sealed box volume of 35L - 56L gives a Q of 0.62 - 0.55 but the F3 point remains around 44Hz. Does that sound about right? What's the difference between F3 and Fb? And whats a good f3 to shoot for in a car and with a goal of quality not quantity.

A vented box looks good with 50L tuned to 25.5Hz. That gives a 1dB peak. With 100watts to the sub it looks like a 3.5 inch port will do but its 19.7 inches long. Is this a bad ratio of port diameter to length? Is this going to be too boomy when you consider the cabin gain?

I know that for home theater the goal is flat output down to really low freqs. But with all the cabin gain in an auto application I don't really know what to shoot for. I guess at this price I could order a driver just to experiment with!

 

[Jack Gilvey]

Hi Ryan,

Just go with the default Q values in Unibox. They change automatically due to amount of stuffing, etc.

In a car, I'd go with a stuffed 1ft^3 or so box for a Qtc around .7. The cabin gain of a car should allow this to be flat to below 20Hz. A Qtc of .707 is referred to as "maximally flat", and results in the lowest F3 possible for a driver (without adding eq, of course). Some guys even go for a higher Qtc (smaller box) for more "punch".

 

[Ryan Schnacke]

Jack,

The reason I ask about the Q values is that I get an application error every time I try to change the suffing fill amount. Seems like I remember 12 - 15 is a good value for Ql on a DIY box.

As usual, you're a great resource for this kind of stuff. And I really appreciate how generously you use your time to help guys like me.

Alright. I've ordered 2 DVC drivers. One for the brother-in-law's car and one for me to experiment with. Hopefully I'll soon be pitting a DIY sub against my SVS.

 

[Jack Gilvey]

Hmm, I don't know why that would happen with Unibox, Ryan.

You're quite welcome for any help I can offer, and do let us know how your projects work out.

My credit card is sitting here, and it's only 2:00...

 

[Bob Ahlberg]

Jack...
Thanks for the heads up on the PE sale! I was thinking
about two Shiva's but with this great a price on such a
similar driver....well, how can one resist?
They will first be put to use in a spl setting that my
son and I are working on together...then later in my HT.
Have a great day.
Bob

 

[Jack Gilvey]

Yer welcome, Bob. I'm afraid to ask what an "SPL setting" is.

 

[Bob Ahlberg]

Jack...
It's about 3cubes per driver tuned to 40hz with 600 watts
going to each driver in a Ford Explorer. With cabin gain,
it should hit in the mid to upper 140's. It's hard to
imagine what these kids are doing with just two 12" drivers.
The record right now is about 155db.
Bob

 

[Jack Gilvey]

Yikes. Is anyone actually in the car for this?

 

[Bob Ahlberg]

Some do...I won't
Bob