Room "Pressure", Volume, Kappa build, etc.?

[sm31]

Sorry if this topic has been covered already... I searched but couldn't find anything conclusive.

I've heard many refer to "room pressurization" when determining a suitable sub for a given sized/shaped space, but I'm not sure I understand what this means. Is there some type of formula I can plug in to calculate the capabilities required of a subwoofer to "pressurize" my HT Room?

As a newb to all this... how will I know when pressurization has occured? Is there some sort of threshold where a sudden increase in performance occurs?

For reference, my room is about 2900 cubic feet (roughly L18xW13xH12) with 2 fair sized openings about 9 ft high x 6 ft wide. I have gotten so-so performance from my generic 120W ported 12" sub, corner loaded. I have begun acquiring parts to do my own Kappa build (already have the speaker). Is it reasonable to ask whether this sub will be able to pressurize the space adequately. BTW, I'd love to do 2 but just 1 is a bit of a stretch right now.

Thanks!!!

 

[fredk]

Pressurizing a room is a poor term. To pressurize a room you would seal it and pump additional air in from the outside to increase the internal pressure.

Subs create pressure gradients (sound waves) in a room. The bigger the room is, the more air your woofer has to move to give you the same volume (felt as 'pressure').

Hopefully someone that has experience with the Kappa will be able to answer your question about its capability.

 

[WmAx]

If you build the cabinet exactly as specified by avaserfi and use a 800WRMS or higher power amplifier, the Kappa Perfect subwoofer will likely produce about 3x (10dB+) higher SPL overall as compared to the average 12" generic subwoofer. In addition, that higher SPL will be absolutely distortion free, unlike your generic sub, that even creates audible distortion at lower SPL.

-Chris

 

[lsiberian]

Sorry if this topic has been covered already... I searched but couldn't find anything conclusive.

I've heard many refer to "room pressurization" when determining a suitable sub for a given sized/shaped space, but I'm not sure I understand what this means. Is there some type of formula I can plug in to calculate the capabilities required of a subwoofer to "pressurize" my HT Room?

As a newb to all this... how will I know when pressurization has occured? Is there some sort of threshold where a sudden increase in performance occurs?

For reference, my room is about 2900 cubic feet (roughly L18xW13xH12) with 2 fair sized openings about 9 ft high x 6 ft wide. I have gotten so-so performance from my generic 120W ported 12" sub, corner loaded. I have begun acquiring parts to do my own Kappa build (already have the speaker). Is it reasonable to ask whether this sub will be able to pressurize the space adequately. BTW, I'd love to do 2 but just 1 is a bit of a stretch right now.

Thanks!!!

I think the Kappa in an excellent design in that it demonstrates how to build a slotted port sub properly. It will easily fill your room. Remember most commercial subs could never keep up. Maybe the Ultra and a few other gems could hold their own, but your sub 1000 subs just have no chance.

 

[sm31]

Thanks for the replies!!

WmAx and Isiberian, I just want to personally thank you for what you contribute here. I've learned so much from you guys!!

After reading my post over again, and your responses... I realized my first post was sort of a roundabout way of asking whether or not my Kappa project (exactly following Avaserfi's design) would be adequate for my space. Geez... 3X the SPL over my weak, boomy mess of a sub... I'd say that's enough! (for now)

I've followed all the Kappa build threads in the DIY section very carefully and noticed many who have built these subs went ahead and built 2. Then, judging by the pics, it looks like some of the "double" builds were put in rooms a good bit smaller than mine. This prompted me to wonder whether I would see substantially improved sub performance or if I needed to cross some sort of threshold based on room volume that required 2+ subs.

BTW, since this thread refers to a DIY sub, maybe I should have started it in the DIY section... Sorry about that!

 

[lsiberian]

Thanks for the replies!!

WmAx and Isiberian, I just want to personally thank you for what you contribute here. I've learned so much from you guys!!

After reading my post over again, and your responses... I realized my first post was sort of a roundabout way of asking whether or not my Kappa project (exactly following Avaserfi's design) would be adequate for my space. Geez... 3X the SPL over my weak, boomy mess of a sub... I'd say that's enough! (for now)

I've followed all the Kappa build threads in the DIY section very carefully and noticed many who have built these subs went ahead and built 2. Then, judging by the pics, it looks like some of the "double" builds were put in rooms a good bit smaller than mine. This prompted me to wonder whether I would see substantially improved sub performance or if I needed to cross some sort of threshold based on room volume that required 2+ subs.

BTW, since this thread refers to a DIY sub, maybe I should have started it in the DIY section... Sorry about that!

Some folks haven't been satisfied by the build, but the cost of building a better sub is much much higher. I personally am building a TC Sounds TC1000 because I got a sick deal on it locally. But Let's be honest the Kappa Perfect is better than any sub in any Best Buy I've ever visited. IOTW your friends won't be able to match your sub unless they are audiophiles with serious change. When my friends visit they think my setup is insanely good. And I'm still using a Dayton sub. A pair of Kappas would own my sub and yet my sub is perceived as very good by non philes.

Sometimes you need perspective in this hobby. Knowing when good enough is good enough is one of the foremost qualities of a great engineer. If dual Kappas don't meet your desires then you will have to get a 400 dollar or great driver and put it in a much larger cabinet.