Just bridged my TFM-75 mono

Aparintly my Audio Control Richter Scale III has an option for non bridgable amps.

You plug the second set of preamp outs to the Audio Control input and select the invert option. Then hook up to both positive sides of the amp with the speaker wire. The invert converts one side to (+) and the other side to (-)...volia the amp is bridged mono into one speaker. Namely a subwoofer.

Also tried this with the 400x7 by bridging two channels the one sub and using another two for the main speakers. Long story short, with everything pulling off of one dedicated socket I was able to pull 17 amps for a short period of time. Didnt go any longer for fear of breaking a sub, but let me just say 17amps will make everything and I mean everything in the house shake. The port on that sub was blowing massive air.

Next experiment is to try both subs with the 400x7 with two chennels running to each sub and two more running to the mains.

Also another neat option is the Warble Tone Generator that uses a microphone and has a dial that goes from 125HZ down to 22.5HZ. Its a great way to see just how low you speaker will go before they lose all effiency and quit producing sound. Down to 31.5Hz everythin works real well but as I lower from there to 22.5Hz you cant hear or feel much of anything.

" Down to 31.5Hz everythin works real well but as I lower from there to 22.5Hz you cant hear or feel much of anything."

Could be your hearing~

That actually sounds about right for those subs, assuming you went with factory box size and porting. You typically don't get much below a woofers Fs.

http://www.jlaudio.com/12w7-3-car-audio ... vers-92112

Woofer:

Free Air Resonance (Fs) 27.2 Hz

Cabinet:

Tune to 36.7 Hz
F3 31.5 Hz

Cool, MRHP! But be careful: IF you happen to "hit" some frequency that resonates with some STRUCTURAL mode of your house (and dwell at that frequency for too long..), you could literally shake it (i.e., your abode!) to pieces....

Interestingly, I'm currently doing acoustical analysis at work on the next gen "moon rocket" and acoustic response (of a structure) can do a lot of damage (fatigue, etc.). They use similar (?) high powered amps to "yell" (rocket engines are WAY up there in db's...also noise from the aerodynamics off stuff sticking out into the airstream at mach whatever..) at the structure when doing these tests...

Its a great way to see just how low you speaker will go before they lose all effiency and quit producing sound. Down to 31.5Hz everythin works real well but as I lower from there to 22.5Hz you cant hear or feel much of anything.

Mine do that as well (Fs 16 Hz) Hoping enclosures help when I get a round tuit.

Noticed that the Richter doesn't eq below 20. Wonder if anyone makes an eq with infra bass capabilities other than shelving. Any idea?

Most if not all audiocontrol products tend to have 15/20 hz high pass filters. A call to the engineers at audiocontrol would find out if this is true and if it is, they will tell you what resistors to swap and were.