What of these for sub duty?

[leadbelly]

Today's Deal of the Day at PE:

http://www.partsexpress.com/pe/pshow...85&dotd=122004

I know, I know, they are PA drivers, but they look like they would do at least a decent job as subs if one could live with with the big Vas.

Fs=25 Hz, Vas=16.12 ft3, Qts=0.34, Xmax=6mm, Le=2mH

Did I miss something to consider?

[xstephanx]

One of the dayton DVCs might have more VD. Id look into those, besides with a fs of 25, its going to be a bit difficult making it reach low enough for HT.

[leadbelly]

True, the DVC has more Sd for the same price, but with more than twice as much excursion to do the job, not good for distortion. And plenty of people are implementing subs with a higher Fs than 25 Hz, albeit using active EQ.

I was trying to do a involved simulation, something that looks hard at Le's effect on the response, 2 VC's in parallel etc, something I've never really done before. I just played with Winisd Pro enough to see that it doesn't use Le, at least I could not get it to change the response curve or box calc by just changing the value of Le. Any sim guru's reading this?

[simon5]

If you want to change the Le parameter in WinISD Pro, you need to change it, save the driver parameters, and load it in a new project.

[leadbelly]

Originally posted by simon5
If you want to change the Le parameter in WinISD Pro, you need to change it, save the driver parameters, and load it in a new project.

I can change Le just fine. The result does not change, so Winisd is not using it.

[simon5]

That is not true, WinISD Pro uses Le.

If I change Le, the high frequency response of the driver changes dramatically.

You didn't follow my insctructions or you are not using the lastest version.

You must change Le, save parameters, open a new project, reload the driver and see the changes.

[leadbelly]

OK, I see the difference now. Thanks.

[simon5]

No problems

Will you choose the DVC or not in the end?

[leadbelly]

Still keeping my eyes open for a sale.

[paulspencer]

That sub should have about the same VD as the Shiva. It actually looks like a good buy.

In a big box it gets a very similar response and max SPL to the Shiva with 350w, while the 18 needs only about 100w.

You can get an F3 of about 30 Hz quite easily and exceed THX requirements.

In a 250L box it can match the output of the Shiva above about 23 Hz when tuned to 25 Hz. 109 dB @ 25 Hz

If you don't mind big and ugly, then it's a bang for buck way to get low distortion, not only due to the low cost of the driver, but also low amplifier cost. Very easy to power.

From a performance and linearity point of view, it's probably a good idea to have a large SD and low xmax rather than a small SD and large xmax. It's also a good idea from a budget point of view. Trying to get low distortion with small subs is expensive!

20 Hz anechoic extension is not needed. Room gain can easily extend useable output, and many rooms don't handle 20 Hz that well anyway (rattles, etc). Also, most of the fun bass in movies is around the midbass anyway.