I have a fairly capable sub system currently able to hit reference at the LP from 20 Hz up. I am only just barely able to do this as I'm using an IB. I want to be sure I am capable of the extra db requirements derived from other high passed channels. I have a few thoughts in mind. I could change over my IB to ported and get massive gains from port loading (likely ported to 15 Hz. following notnyt's example), I could add more subs, likely be 4 18s in sealed boxes, or I could add a sub to each LCR capable of hitting the 105db reference for those channels. I have always read that with proper bass management, i.e, THX @ 80 for all channels and a well balanced and tuned sub system capable of the full range of headroom needed is better than having true full range speakers. Any thoughts?
What kind and how many subs do you have in your IB currently? If you have the space for multiple large ported subs and have the time to build them, that seems like the cheapest way to go.
I have 4 FTW 21. I have been trying to figure out where to put 4 30+ cubic foot boxes around my theater. I have room for two behind my screen, I may have to get tricky with two more. I want to tune to 15 hz...which is a huge box...but, if it is for science
I'm running into trouble finding places to put ported boxes in my theater...just too big for the FTW. I did some modelling of putting all the FTW in sealed, dual opposed boxes and adding 4 SI HTD4s sealed, also dual opposed into the mix, but according to an online calculator:http://www.sengpielaudio.com/calculator-leveladding.htm, I would only gain less than 1 db of output. Can that be right? The reason for the IB to sealed change is the in room response of my IB. It is generally too messy to fix. I know it is said if the drivers are coupled, a 6db increase in bass is realized, but only one Db from 4 more subs, albiet far less capable subs, seems way off. I will also note...I have virtually no room gain for some reason.
Would the additional subs be a waste of money? Just trying to get my reference level up with a bit of headroom.
That calculator is not the easiest to add with, especially with different drivers/enclosures with different FRs. It also depends upon how you're powering them.
How many FTW21 do you have?
I have 4 of the FTWs Using winisd I get almost 136db from the four FTWs @ 20 Hz when ported and tuned to 15 hz. When sealed, I am limited to 127db. At 15 hz I get over a 10 db boost ported, just not sure I can do over 130 cu ft of boxes.
The front is a 3' x 11' x7' area behind an AT screen. My one big hurdle is that my electrical main comes in on the right hand side and I cannot build in front of it. So an area about 30" down and 20" from the right wall need to be accessible. Seems like the best I can do is house two large subs behind the screen and my mains, which are 5 cu ft each and currently sit on top of the IB manifold.
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