small amp on four 15s will it overheat?

[hispls 5,000+ posts]

Holy cow man....had trouble cutting that circle with the jigsaw?! http://www.partsexpress.com has a jasperjig to make perfect circles every time.
Those ports aren't that long....was expecting to see something insanely longer....lower tuning requires longer vent length.

That is very little port area compared to what conventional wisdom tells us to use. Of course with only 700W or so on tap it may be adequate at least to avoid damaging the subs.

Honestly I think if OP has the space to double up box size he'd do better just building a bigger box with a proper port than trying to cram in more cone area.

 

[Jeffdachef 5,000+ posts]

Yeah im quite limited on space, it is in a nissan leaf haha, two 105ah batteries run in parallel behind the back seats hooked up to the JBL monoblock, had to remove the oem Bose "subwoofer" to free space for the batteries.
The plan with the box was actually to have four 4"/30" ports and tuning about 35hz, but i tried with just two at first and i was quite surprised how insanly low it played ..went on the pc and calculated (like the pic above) there was a big surprise when i found out that the box was actually tuned to 20.5hz with just 2 port (iknow why but still surprising) no wonder that the lows are almost a little louder then the 37++ hz. Yet another surprise when i found out i can hear all the way down to 17hz hehe.

The port velocity / port noise was not as bad as i thought, can barely heat them probaly becouse of where they are placed with the back seat acting as an absorber of some sort

But im allways looking for more output so ithink i'll try with adding just one more sometime in the near future. See if a little higher tuning + less port noise is the next "upgrade"

if you want to do 4 15s, might as well do a wall man. Because right now you are suffocating those 15s.

 

[Boomin_tahoe 5,000+ posts]

Does everyone realize OP is using subs from home speakers and removed them to put into a box??

I wouldn't know the cu ft. recommended for such a thing....home audio vs. car audio.

 

[n2audio 5,000+ posts]

if you want to do 4 15s, might as well do a wall man. Because right now you are suffocating those 15s.

Nah -- these aren't big xmax super low 15" car subs we usually see around here. CV's FR is only down to 38.

Definitely giving up some boom tuned that low, but the trade-off, of course, is playing flat.