Dual 15" HT build

[annunaki]

Hi all!

Seems like the better part of a decade since I last posted a build project here. Kinda sad on my part I suppose but, 2 kids and a foster child plus the two we had keeps me a bit busy.

Anyway a friend of mine is doing a theater in his basement. It is a fairly large space so we needed some displacement. We arrived at using dual Pierce Audio 15" 1K subs in 4.5ft^3 net volume sealed enclosures. These are the older versions than what it currently on the site using the pressed pulp/Kevlar cone.

There is a small peak around 58 hz that we will tame with a mini DSP. Overall f3 was 32hz.

I will have to find my model screen shots since this build took a long time between design and execution phases.

Anyway, here are a few pics of the build process.

 

[fuzz092888]

Very nice, that's the 15" version of the same sub I have.

 

[rojo]

Nifty! Just curious, but why sealed? Was it for the shallower subsonic drop-off?

 

[fuzz092888]

Nifty! Just curious, but why sealed? Was it for the shallower subsonic drop-off?

Could be size issue period since you can usually go smaller with a sealed sub anyways. Two drivers, increased surface area, in a cab not much bigger than going vented would be.

Are talking frequencies below 20hz? That's infrasonic. Subsonic refers to speed below the speed of sound.

 

[lovinthehd]

Could be size issue period since you can usually go smaller with a sealed sub anyways. Two drivers, increased surface area, in a cab not much bigger than going vented would be.

Are talking frequencies below 20hz? That's infrasonic. Subsonic refers to speed below the speed of sound.

Subsonic works http://www.dictionary.com/browse/subsonic

 

[fuzz092888]

Subsonic works http://www.dictionary.com/browse/subsonic

Barely. Subsonic is much more closely related to the speed of sound and in the realm of fluid mechanics and while it can be used to describe sound waves that are too low to be audible, it's an awkward fit if you know what the word means and how it is normally and technically used in the common vernacular. Infrasound is a much more appropriate fit because while it also describes sound waves too low to be heard, it is more specific to acoustics and the generating or employing of those sound waves.

 

[lovinthehd]

I just said it works . Ultra low frequency when it comes to subs is even better.

 

[annunaki]

Originally I had planned for vented in roughly the same size enclosures. Especially considering that is what I communicated to Mr. Pierce upon ordering. When I received the woofers and verified the TS parameters, I did not have 10.5ft^3 available for optimal vented per 4.5ft^3 sealed was going to have to be it.

Knowing the woofer has adequate power compression characteristics and verifying through modeling, we were only giving up about 4db by the time 20hz rolled around using a mini dsp.

As for description of low frequencies, I agree in the term infrasonic as it does more adequately describe said frequencies. "Infra-woofer" just does not sound as good as "subwoofer" which is probably why subsonic is not commonly used as a description.

 

[rojo]

Next y'all are going to try to tell me it's infrared, not subred. Psh.

You're right, of course. Sorry for the rookie moment, and thanks @lovinthehd for joining the revolution! Still, @annunaki thanks for satisfying my curiosity.