[RobertR]

I want to add a subwoofer to my bed room micro system. the receiver has a sub out but most of the subs I looked at dont have 2 way xovers. In other words how can I keep lower frequencies out of the sattelite speakers. There must be a sub out there that has a built in xover. Most of these only have a high pass filter for the sub.
Ive looked at polkpsw202, infinity ps8 and velodyne ch8 all priced from 199.00 up.

My old velodyne uld12 has a seperate xover with level control.
I understand that some receivers have built in control for the xover but not mine.

 

[ooheadsoo]

Many audiophiles don't agree that adding a non-specialized crossover to your speaker system of questionable quality is hardly an added benefit. That said, I believe many people use the behringer feedback destroyer as a cheap subwoofer active crossover tool. It has an eq tool that you can use to bring down the lower end of your satellites. It's probably your most versatile option, is portable from system to system as you upgrade, and it's not too expensive, rather than being stuck buying some amp you don't need.

 

[gerG]

I think your best bet for the micro system is to add a passive high-pass to your satellites. That consists of a large bipolar capacitor in series (in the + side). The crossover point is a function of the woofer impedance and the capacitance value. This is basically a 6 db/octave high pass, so it won't be a sharp cutoff. otoh it will give the benefit of reducing the cone motion (and the associated IM distortion) of the woofers in the sats.

I don't remember the equation, but I will look it up tonight.

If you decide to get more serious and go with an outboard active x-over, Behringer makes one for around 100 bucks that works great. It has to go upstream of both high and low amps.


gerG

 

[ooheadsoo]

gerG, isn't that the feedback destroyer that I mentioned, or is there something else for $100?

 

[gerG]

It this:

Behringer 3-way

They also make a 2-way (cheaper), and the more exotic digital crossover that they just introduced (more spensive).

The equation for the high pass is: C = .159/(R * f)

where C is the capacitance, R is the impedance of the speaker at the x-over frequency; f, which is the frequency at which the output is 3 db down.

gerG

 

[ooheadsoo]

Oh, wow, that would be nice. It handles the subwoofer's crossover too though. The feedback destroyer offers only a single EQ and it's about $30 cheaper, so in a desperate pinch I guess you could go for the feedback destroyer, but it seems like the crossover would be a good investment.

 

[gerG]

Keep in mind that the above is a 3-way crossover. If you aren't tri-amping, the 2-way is only around $90, and can probably be found for less. The drawback is that they all have XLR connectors, so you need either adapters (yuck) or cables with XLR on one end and RCA on the other. This solution works splendidly, especially if you make your own cables.


gerG

 

[gerG]

Hey, I just noticed that the new version of this one has a dedicated mono subwoofer channel as well. You can still triamp! (and spend all of your spare time making cables and amp rolling).

Before anybody runs out and orders one of these I should warn you that you must have a preamp output and accessible inputs on your main amp as well as the sub amp. Pre-outs and main-ins used to be common on receivers and integrateds, but is tough to find these days.

gerG