lfm1 sound problem

Posted by: conextions

lfm1 sound problem - 09/09/06 07:04 AM

HI all, I'm new to the scene here, just got my outlaw 7500/990/lfm1 combo yesterday and have finished connecting everything and I have a problem with the subwoofer. Very little sound is emenating from the woofer, when I touch the woofer itself it is barely flexing with the volume and gain raised. I am using a sub cable with a y-adapter at one end and just plugging one into the sw1 pre output on the 990, would I need one with single plugs on both ends or is there no difference with the extra plug. I am just starting in the home audio realm and will most likely have more questions as I progress, thanks for your time and help.
Posted by: Jason J

Re: lfm1 sound problem - 09/09/06 07:59 AM

Forget the Y-cable, that's doesn't sound like the problem. It sounds like for some reason, you're not getting enough signal to the sub. There are a whole bunch of possible solutions to your issue so here is a short list of things to check:

1) What are your crossover settings in your 990?
2) Are your speakers set to small or large?
3) What kind of demo material are you using where you're expecting a large sound from the subwoofer?

Those are good starting points. I would also advise that you check out the 990 saloon and look at all the posts about bass management. If you don't have your settings correct, your subwoofer won't work the way you expect it to. Let us know how your tests go.
Posted by: conextions

Re: lfm1 sound problem - 09/09/06 08:10 AM

the speakers I have are Alegria Audio Rosa LCR for the front three along with 2 Alegria Audio Ling II's for surrounds all set at 80hz in the 990. All speakers are set to small and I was demoing the first matrix movie. I'll look into
the 990 section as you suggested. Would a dedicated system setup dvd help or is the 990 setup adequate enough?
Posted by: conextions

Re: lfm1 sound problem - 09/09/06 08:30 AM

Also I saw that I could do the test in manual with a spl meter from radio shack. How would you go about doing calibration for reference level sounds?
Posted by: gonk

Re: lfm1 sound problem - 09/09/06 01:46 PM

The bass management settings sound like a good starting point. I'd start out by setting the volume dial on the LFM-1 to around 5 (mid-point). Manual calibration is pretty straightforward: switch to an unused input and set the 990's volume to 0dB, then go to the channel calibration menu. Set the test tones to "manual" and scroll through each channel individually. Sit in the sweet spot and hold the SPL meter with the mic pointed at the ceiling (set to C-weighted, slow, and 70dB scale). Adjust each channel to achieve 5dB on the meter (which equates to 75dB, or reference level). You'll probably end up tweaking the sub a bit even after this. SVS has a lengthy list of bass demo material that might help you find some good low frequency samples.
Posted by: Jason J

Re: lfm1 sound problem - 09/12/06 12:15 PM

I may have been incorrect in my earlier post. I didn't realize the LFM-1 has only one input jack. You may want to try connecting it with a mono RCA to RCA cable and see what happens. I apologize for any confusion.

"The Matrix" should be fine for test material. If you have any "THX" certified DVDs, there's a great bass sweep in the "THX" optimizer. It's a tone sweep that goes from 200hz to 20hz. That kind of sweep is great for hearing what your crossover is doing and also what the bass frequencies are doing in your room.
Posted by: gonk

Re: lfm1 sound problem - 09/12/06 12:21 PM

Another convenient source for test material is my Devious Tiny Disc (DTD) - there are two disc image files, one a DVD image that can be burned to DVD-R and one a CD image that can be burned to a CD-R. Both contain test tones that sweep from 20Hz to 6000Hz in the left and right channels separately - a handy way to observe what the bass management is doing.
Posted by: conextions

Re: lfm1 sound problem - 09/18/06 03:03 AM

thanks for the help guys, got the lfm1 sounding fine now. First problem was I had to switch my dvd player from pcm to digital and replacing the sub conncet with a mono rca instead of the y adapter cable really helped on top of that.