Build something comparable to SVS PB13-Ultra? - Page 3

sorry, i've been away from the thread... got busy with other stuff.

actually, to clarify IB was never in consideration. I think that was brought up because I didn't specify that I was looking for SVS PB13-Ultra level audio performance as well as approximate size and type of box. So all of the IB type of designs are out.

I haven't yet had time to get on a box designer program to play around with drivers and designs but my impression is that the Mal-X is will probably be too big/too expensive. The design that seems to come closest is the 24" cube with AV15X+2x18" PR design.

However, while the cost of the AV15H at $250 is ok, adding on the two PR's at $125ish each puts the base component costs at about $500 already before the amp and wood. How big would a similar design, but with a slot port have to be?

glad to see there is still some interest in this topic. i'm the OP but still haven't gotten to building anything since my friend with the full garage woodshop was moving houses (and now his wife is prego so i should get in gear to build this before the baby arrives).

one thing i can't understand is how the SVS gets such a low 20Hz tune with 3 relatively short 3.5" diameter ports in a pretty small box? And plugging one port tunes to 15Hz and two ports tunes to 10Hz? Doesn't this go against what other posters are saying about needing 10" diameter ports, 131 inches long?

i guess the question raised by notslow's and my postings is:

how can the PB-13 Ultra achieve it's high spl and low freq performance, while having a small box size, one 13" driver, less amp power, and only 3 short small diameter ports? and how does plugging ports lower the tune?

if we can identify how they did this, that would help us figure out how to build something comparable.

yeah, this is the closest design we've come to in this thread.

the thought flow seems to go like this: to go low, you have to tune the box low. to tune the box low, you have to have a larger box and/or bigger ports and to tune the ports low, they have to be super big or long, usually way too long to fit in the box. so instead of long ports, let's use passive radiators since those can be weighted down to tune to any frequency. and that's how we arrive at this design.

however, if you look at the SVS design, it pretty much contradicts every rationale used to arrive at the 2 PR design: it has smaller box; reasonable diameter ports that fit inside the box yet are tuned very low; and needs "only" 750W of amp power as well.

so it still raises the question of how the SVS design can work so well. if it is in the design of the driver, then what parameters are being optimized for this to work and do none of the other DIY drivers able to work like this? if it is the design of the box, then how come we can't design a DIY box like this?

sorry for over analyzing, but the engineer in me likes to understand things.