Subwoofer RCA crossover - maybe linkwitz, not sure.

[RobxMcCarthy]

Hmm, well, for now I'm running my subs out of the sub-out on my audigy 2. Sounds good, I have bass re-direction at 65 hz because the speakers (mains) are flat (-3db) down to about 35, so I figure the 2 subs can pick up at about 65 and the mains can start dropping off there. 80 hz is thx standard but I've tried that and I don't like it.. heh.

However, this fall I'll be moving back to college and the speakers will be out in the common room. There will be multiple input sources so I'm not quite sure how I want to deal with this. In all probability I'll build an RCA switching box for the inputs and only have one input on the receiver and one input on the subwoofer amplifier.

So I'll have multiple RCA's coming into the switch, two channels coming out. I'm then either going to integrate a linkwitz 2 - way crossover in the switch or make that an external box.

But basically, I probably want to have a linkwitz crossover at 65 hz with a SLIGHT boost on the lower end approaching 20 hz, but nothing extreme. I probably also want to go with a 12 db / octave cross-over, so 2nd order. I have some experience building crossovers but have never tried a linkwitz before. And, I've never done an RCA crossover. Is the signal strong enough to tamper with without a line driver? Or will I need extremely sensitive components + a powered unit?

My reason for doing this is that although the Mackie and the plate amp have crossovers there's still a lot of leaking, which makes me think they are only first order, which isn't enough for a sub. I don't want vocals to ever come out of my subwoofer, lol.

Hopefully ryan will have some input.

 

[Ryan T]

It will probably be pretty hard to actually build an active crossover. I really dont know anything about active crossovers but the price for a passive network with an under 100 Hz crossover point would be really expensive. You may think about using an automotive crossover. They range from as low as 50 Hz to as high as 180 HZ but they use a 12 dB per octave crossover and accept RCA line level inputs.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=267-766

They wouldnt provide you with a boost you wanted but it's going to be much easier that trying to build an active one .

What type of amp do you have running it now? I'm using the standard PE plate amp for my Tempest and it has a variable crossover fro 40 to 170 Hz. I leave it around 50 Hz usually but I can push it up to 100 Hz without vocals really comming though.


Ryan

 

[RobxMcCarthy]

Well the vocals don't REALLY come through. My bottom sub has a PE 150 watt plate amp. Top sub is running out of the mackie. in both if the volume's high and the speakers are off I can hear the full range if I'm close It's not a huge problem but it's a waste to have that crap bleed through as it negatively effects the sound quality of the sub. After running it through the sub-out on my computer at 65 hz the quality sounds much better.

 

[Korndog]

you oculd try these..
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=266-254
they actually work pretty well and harrison labs is a great company, wouldn't doubt the quality if they made it.
they also have a 70hz version..
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=266-252

 

[RobxMcCarthy]

Wow, I've never seen those before... I wonder how well they work.

 

[Ryan T]

I've used them before several times. They sound just fine with the RCA line level inputs. But if you have to use the high level they do leave a bit to be desired .



Ryan

 

[RobxMcCarthy]

They'll be used on line level connections. pre-amplifier. Maybe I should try them, but $56 is mighty rich for something that MIGHT work =).

Hoever, parts express has been nothing but helpfull to me.

 

[Ryan T]

Oops, I didnt see Korndogs post. I've never used the Fmods before but the car audio active crossovers I have. The active Xovers are about $20 and work great as line level.


Ryan