View Full Version : Low Pass and subsonic settings
03-03-2002, 11:30 PM
I've got two MM100's and a Lanzar Vibe 1200D amp in a small sealed truck boxes. I was wondering what I would want to set the low pass and subsonic filter at to get the most from the subs.
03-04-2002, 09:49 AM
The low pass should be set at 80Hz and shut the subsonic off, because it is only needed for ported enclosures so that the sub doesn't go below the tuned frequency.
L8r, Ken :)
03-04-2002, 09:07 PM
What about the phase switch? Should that be set on 0 or 180? What exactly does this do? Thanks.
03-05-2002, 03:22 PM
That is to be used in conjunction with the crossover.
I believe this is what happens with crossover slopes:
12dB/octave won't change the phase
24dB/octave will change phase
-this just has to do with making the internals of the things work
So that switch when used takes the place of switching(pos to neg) your RCA(external X-over) or speaker(internal X-over) leads to get the correct phase for better performance.
Just install your stuff so that all positives and negatives match to their corresponding + or - and then use this switch to change the phase and see what sounds better.
Hope that helps, Ken
The subsonic filter on amplifiers is used to filter out frequencies in the 0-20/25 Hz range. These low frequencies can barely be heard by human ear. If the amp does not have to reproduce these frequencies, it can work more efficiently.
The phase switch will flip the output of the sub 180 degrees. This means that it will switch the positive and negative terminals. This can help to "blend" the subs with the rest of the system. Try it both ways and see which sounds better.
The crossover can be set anywhere from 40-120 Hz. I personally like to set it at 50-60. Most systems I build utilize midbass drivers, though. Any other questions can be directed to Polk's customer service department.
Happy Bassin' (as Kim would say)!
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