Adding another mtx9500 Q about low tuning

[HelloImBob 10+ year member]

Ive been trying to decide on how low to tune my next box, Id like it to sound clean and rumble on the low lows, right now Im running a single 12" 9500 @35hz in 2cu. Ive been thinking about building a box roughly around 5cu @ 27hz with like 62in^2 port area.

I put the specs into winISD and im happy with the response id get from it, I was just hoping to get some words of advice from somebody whos tuned low for sq with kinda non sq subs

also I was wondering if this sub would even preform well at 27hz with its fs of 36.4hz

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[DNick454 10+ year member]

To be honest, I think 27 Hz would be too low and would fall flat on it's face in the upper region of music. I'd say if you want to go lower, don't go too much. Maybe try 32Hz? It also couldn't hurt to bump up the port area a bit, unless of course you're planning on using aero's. 5 cubes is also quite a bit for 2 12's.

 

[HelloImBob 10+ year member]

hmm thats what I was afraid of, I could do 32hz, but I might be happier if I could get away with 30hz and the only reason I was going to do a 5cu box was because winISD was showing much better response with that extra cu ft between the 2 woofers

 

[DNick454 10+ year member]

Keep in mind, WinISD will never correctly recreate a real-world result. MTX actually recommends 1.75 cu ft per sub for a total of 3.5, a tad far off from the 5 you were looking at. How much power RMS will you have available for both subs? I'd say that would be the biggest determining factor as far as net volume goes. I'd shoot also for around 100 sq in of port area because of the large excursion of these subs.

 

[HelloImBob 10+ year member]

well hey thats great news Im all happy with a smaller box, as for power I figure 800rms each maybe a little more if I can squeeze it out of my electrical. Im running a MTX92001 capable of 3000+ rms @1ohm

edit:: hmmm seems id need around an 8" port for 100sq in of port area? which would throw my tuning all off unless Im not understanding the sq port area correctly. I was figuring around a 4" square port just roughly doubling the size of my last port and box to make a new box, just tweaking the tuning a bit

 

[DNick454 10+ year member]

Basically, if you make the port larger in cross sectional area, the tuning goes up. Therefor you must make the port longer to lower it back down again. So it ends up taking up more room to get the same tuning, but the subs can breathe easier, too small of a port area and performance will be affected and you could get turbulent port noise.

 

[HelloImBob 10+ year member]

makes sense and I think Ive finally decided on an overall box size, tuning and sq port area. thanks for all your help this is only my 4th box build and I wanted to make sure this one came out just the way I wanted.

One more question tho, I wouldnt be able to use a L-Ported design because one sub would be closer to the vent and move differently? Ive never had to deal with 2 subs, Ive always just used one...