Post by wesleynance on Dec 27, 2016 8:16:14 GMT -7
I discovered this forum over ten years ago, and quickly upgraded the sub in my HT room (dual passive radiator sub with Stryke 12" driver) to an IB running 4 15" Dayton IB drivers powered by a dedicated 450w pro amp. I've never looked back!
This Christmas the big family present was a complete overhaul of the HT. JVC projector, Marantz receiver, new screen, etc. we rotated the room 90 degrees to facilitate a 131" wide 2.35:1 screen. This is a huge improvement on all fronts, but creates two challenges with my IB:
1. Instead of the IB bring at the very front of the room on the left wall (my only option), it is now on the back wall at the left corner (room rotated 90 degrees clockwise), leaving it behind me. I've only done a bit of listening/movie watching, so still deciding what I'm hearing. The receiver has Audyssey platinum (X32) which has sub eq, so that's in the mix as well. I had been running a BFD for parametric eq, and may still insert that into the signal chain somewhere. I'm crossing over at 80hz, all speakers set to small.
Anything else I should take into consideration? I don't know that I'm able to change the phase of the sub with this setup.
2. The projector has been mounted behind the rear wall, shooting through the smallest hole possible (3.75" x 6") but that hole is on the same wall (19' x 6.5'h) as the IB cutout about 8ft away. Do I need to worry about this messing up the separation between front and back wave?
My receiver can support 2 subs, and Audyssey will eq them together to time align, so I could add another sub in either front corner.
First off what are the main speakers? Do or can they play low enough to support say a 40Hz XO point. If so then having a rear or off axis IB will probably work.
If the mains don't go low consider building a MBM aka mid-bass modules. These are stand alone speakers located in the front of the room that augment the low output from the mains and fill out any hole in the frequency response between the mains and sub.
Phase can be changed 180 degrees by simply reversing the wiring to a speaker.
Post by wesleynance on Dec 27, 2016 9:26:38 GMT -7
Mains are currently high quality DIY bookshelf speakers, so I need to keep the crossover up at least 80hz (that's where Audyssey put it also)
Integrating MBM's sounds somewhat tricky? I'm guessing that sometime down the road I will upgrade my speakers to something bigger, and I could aim for a design that is solid down to 40hz.
Any thoughts about the pj hole in the wall- is that an issue?
I understand reversing phase by switching speaker leads- how is that accomplished with a mono rca connection for the sub? I was thinking if I figured out how to reverse phase I could just try it and see how it sounded. The sub sounds pretty smooth right now- I wouldn't say it's got a ton of punch, so can get dialed in some I think.
Post by wesleynance on Dec 28, 2016 10:50:06 GMT -7
Got it, thanks. Replaced the fans in my NADY amp yesterday and they are very quiet now, so big improvement.
I understand now about the phase, sorry for being a little slow. I can reverse the leads from the amp to the drivers. Got it.
Watched "The Incredibles" last night on the new system, and to be honest it was pretty incredible. So maybe everything is working just fine. I had no issue with the sub in the back of the room. I think my conclusion is that having an IB sub in the back of the room is better than having regular box subs in the front of the room.