4645B Sub - - How much power?

[DLutz]

I just received 2 4645B's which I am using in a 7.1 theater/music setup. I started off pushing them with a Crown amp rated @ 375 watt RMS @ 8 ohms/ch. To my suprize I was so disappointed with my bottom end. I double checked my wiring +/- and even checked each cabinet with the "D" battery check to make sure the PO didn't change some wiring around. All is correct. My room is rather large 22' x 45' and I experimented with some different placements in the room with really no improvement.

I now have stepped up to 2 bridged Crown's rated at 975 watts RMS @ 8 ohms running each cabinet and there is a huge improvment, but still it just seems like something is not "hitting". Actually the amps clip very easily at
high "rocking" levels. Both speakers and amps are performing the same. Its not like one is different from the other.

Does anyone have any experience with these sub woofers? I know they are rated at 1600 continous program power, and my question is am I still under powered or is there something I am missing here?

[4313B]

I've driven them with Citation 22's in Stereo and Mono mode to great effect. That's a whole lot less power than you have. What is your low pass filter set at? You should also run a high pass filter at 20 to 25 Hz to clean them up. Try one on a short wall and one on a long wall.

[DLutz]

Low pass filter is set at 95hz. I tried 100 even 105 and didn't like the sound, but they were a little more puncher. (and louder)


I don't have a high pass filter in the set up for the low end. But, good thought I will look into that. My crossover doesn't have that feature. My EQ for the Rt. and Lf. fronts has a low cut filter, but I am now running the sub signal from my pre amp processer straight to my crossover.

I also haven't tried the long/short wall theory, I have them both up front, 1.5ft. out from the wall just inside my right and left front stacks.

Thanks for you advise
David

PS: I just check the low cut filter on my DBX 1231 EQ. It is a 40hz. 18db/octive filter. Do you think that is too high?

[Rusnzha]

Yup, turn it off!

[4313B]

40 Hz is too high for the low cut filter. One octave lower should be fine. I'd also try to cut them out sooner, 60 to 80 Hz.