crossover

hawker · 04-11-2007, 10:56 AM

I just purchased a psb-subzero subwoofer. It sounds great, but am not too sure where to set the crossover according to my tower speakers, which are rated @ 8 ohms/150 watt max & 32 - 20,000 hz range. the sub pushes 230 watts. Any suggestions?

RickiRed · 04-11-2007, 12:01 PM

Quote:

Originally Posted by hawker

I just purchased a psb-subzero subwoofer. It sounds great, but am not too sure where to set the crossover according to my tower speakers, which are rated @ 8 ohms/150 watt max & 32 - 20,000 hz range. the sub pushes 230 watts. Any suggestions?

Check the freq. responce of your receiver and see where it's cut off is and set your sub right around there.

MaxL · 04-11-2007, 12:17 PM

i may be a little confused. can you tell us what your main speakers and amp/ receiver are? that's a nice little sub for a smaller room especially for music. i auditioned it against some much larger subs and it compared favorably sound quality wise. but if your towers go down to 32hz that's about the bottom end of what that sub can do. that doesn't mean the system won't benefit from using the sub, just that it's not necessarily adding much extension to the low end.

if you're using a surround reciever, you should run the sub on the lfe out and let the receiver do the bass management. if you can, try running the receiver's crossover from 50hz up to 100hz at 10hz increments and see what sounds best to you. if you are running a 2 channel system, it may be trickier.

John Garcia · 04-11-2007, 12:22 PM

Quote:

Originally Posted by RickiRed

Check the freq. responce of your receiver and see where it's cut off is and set your sub right around there.

This is not good info. Normally when using a receiver with bass management, if the sub's x-over does not have a bypass function, you set it to its highest point so the two x-overs do not combine (which would create a super steep slope. By doing this, the receiver's x-over essentially overrides the sub's, which is what you want.

RickiRed · 04-11-2007, 01:59 PM

Quote:

Originally Posted by John Garcia

This is not good info. Normally when using a receiver with bass management, if the sub's x-over does not have a bypass function, you set it to its highest point so the two x-overs do not combine (which would create a super steep slope. By doing this, the receiver's x-over essentially overrides the sub's, which is what you want.

I'm sorry I was talking about the cut off freq of the tower speakers. For instance if I set my towers to large and select a cut off freq for the towers at say 60hz. I would then set the sub to somewhere around there. I didn't want to get into the slope because I wan't sure that it would matter very much to the thread starter. It may not be the perfect setup but it is a good starting point.

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JohnRice · 04-11-2007, 04:38 PM

Rick, either I am completely misunderstanding what you are saying, or you are giving serously bad advice. For one, you can't set the mains to large and set a high pass frequency for the mains as well. Large means no high pass.

Dale, building on what John said, if you have an HT receiver, connect the sub to the LFE output and completely bypass the crossover in the sub itself. If it doesn't have a bypass, set it to the highest frequency available. Also, your speakers say they go down to 32Hz, but is it at a severely crippled output or at high distortion? Without more info on the mains, I would set the crossover on the receiver around 80Hz to begin with. People often want to set it too low, which just makes no sense for many reasons.

John Garcia · 04-11-2007, 05:08 PM

Some receivers do allow setting of x-over by speaker "type", meaning mains, center, surrounds, etc.. but that setting still adjusts both the high and low pass, so the same advice applies in terms of the sub's built in x-over.

RickiRed · 04-11-2007, 05:19 PM

Quote:

Originally Posted by John Garcia

Some receivers do allow setting of x-over by speaker "type", meaning mains, center, surrounds, etc.. but that setting still adjusts both the high and low pass, so the same advice applies in terms of the sub's built in x-over.

I haven't changed my set up in quite some time but if I remember correctly I have frequencies for the 5 mains at 60, 80 and 100.

So John G. If I set my speakers to large and select say 80hz as the crossover point what is that doing to my towers exactly? I am coming from a car audio background and when we set up the front speakers and select the crossover point on the amps or processor I am telling it not to send any information 80hz or lower to these speakers. Please tell me what I am missing. I don't mean to give out incorrect info.

John Garcia · 04-11-2007, 05:58 PM

Your center may be your limiting factor there, because with the RF-3s, you should be able to handle a 60Hz x-over. I'd try it out and see how the center handles it; it may be a bit too much bass for it to handle. 80Hz should be OK for your setup though.

You are not completely removing sound below 80Hz, but rather decreasing it as you go beyond 80Hz and the opposite occurs for the sub - though the low pass is generally steeper than for the mains (~12db/octave for mains, 18-24 for the sub). That means your mains will still be getting down to at least 40Hz, just at a much reduced level and with a 60Hz, you can expect some output down to 30Hz. Like I said, try it out and see if you like it and if it strains; if it does, put it back to 80Hz

I got started in car audio as well