A buddy of mine stumbled across 2 DIY subs on CL. He's trying to figure out if they are going to be better than the single SVS PC-Ultra cylinder he has now.
The guy doesnt remember exactly what the port tune is and that will make a large difference in if these are better or not.
The sub being used are 2 RSS390HF-4 (one per box), and I have the external cabinet dimensions from the seller:
External dimensions for each box is 25.5"L x 19.5"W x 26"H, I think I used half inch MDF, doubled up the front baffle and countersunk the driver
I also have the port diameter (3") and length (20.5" deep flared on both ends)
The builder thinks that each is tuned to 30-32hz, but when I put 6.5cf (approximate internal volume), a 30hz tune, and 2 x 3" ports, I DO NOT get 20" of length in WinISD. If I adjust it to around a 20hz tune, then it seems to be right....
Can someone double check me as if the sub is tuned to 30hz that makes a difference as this is a HT only system.
I know 2 15" ported subs should be much better than a single 12" ported, but if the 15's are ported high, they might not reach down low enough for HT use. So I'm trying to figure it out.
The other thing is that the SVS is powered, these are not. I realize a iNuke 1000 or 3000 DSP is an easy fix, but depending on how much power the subs can take (which is a product of port tune and length to keep both excursion and port velocity low) helps decide how much EXTRA he needs to spend besides just purchasing the subs.
So if someone could help me reverse engineer what the port tune is, or verify if it is INDEED ~30hz that would be much appreciated.
PS, my friend is NOT looking to DIY himself, but doesnt have a problem buying DIY subs, assuming they pass WAF