Crossover Questions

Hey guy's,

   Question on the proper method to set the crossover points for a set of 6.5" Mid bass's driving them with a 2 channel amp?

  Chris

I am running my components Bi-amped. The high end is set at 2.5k mid low is set at 125hz and mid hi is set at 1k and the subs are set at 80hz.

  I am using the internal crossover in my head unit and will have to go with an external for the midbass speakers that I am gonna install. The mid setting for the components will be raised from 125hz to around 250hz I think. I will have to play around with this a little.

  Mainly, I would like some input as to the type of crossover that I should use for the mid bass speakers so, that I can keep their frequecy between 80 hz and 250 hz.

   Chris

A couple of points:

You say "The high end is set at 2.5k mid low is set at 125hz and mid hi is set at 1k"  If I understand you correctly, this means your mid-bass of the component set is crossed between 125Kz and 1Khz.  (This is called a bandpass filter, BTW.)  But you have the tweeter crossover set to 2.5KHz, right?  This means you have a severe mid-range "hole" between 1K and 2.5K.   You could not choose a worse spot for missing information if you tried.  I suggest setting the mid-hi to match your tweet high-pass.  There should be no gaps between your crossover settings. 

So right now you also have a bass "hole" between 80-125Hz and you want to fill this with additional woofers.  I agree with your proposal to raise the mid-low setting to 240Hz or so after you install your new woofers, which will expand the "hole."  You will need another bandpass filter for the new woofers.  There are several ways to achieve this.

First and best is to purchase an external 3-way crossover like an Audio Control 4XS or 6XS.  This crossover is far more sophisticated than you really need, but with it you can tailor the bandpass section to precisely match the rest of your system.  AC makes some of the best sounding Xovers available, but there are others out there certainly.

A second way would be to utilize whatever crossover is built into your 2-channel amp for one half of the band (either the lowpass or the highpass) and add an external crossover for the other half.  I've gotten good results using the low-pass built into an amp for the top of a band, and adding an F-Mod type high-pass filter to the RCA input cable for the low side of the band.  This would be the bargain basement solution.  :)

A third option is to design and build a passive crossover for the mid-bass woofers.  This can create a very nice sounding system, although it is likely to be far more time consuming and expensive than either of the two above suggestions.  Plus, with passives you cannot easily adjust them after you build them if you find you need to fine-tune something, and there is some efficiency lost as the passives use some power.

I hope that helps.

DYohn,

   Thanks very much for your input. I will be adjusting the crossover points right away. As far as the crossover for the midbass, I love Audio Control and have used their products in the past but, for this application the 4xs and 6 xs crossovers just seem to be a bit combersome to program.

   Can you suggest and easier to use crossover that will work nicely for this application? Or maybe I should just go with the 6xs and stop using the internal crossover, possably.

   Chris

I would have to agree that it is a great crossover, just a bit out of my price range though.

 Chris

For a lower-cost solution the Clarion unit is clean sounding.  I've never used one but the Phoenix Gold crossovers are supposed to be nice and clean.   There are nice crossovers from lots of other companies, just avoid Pyle and Audiobahn and Legacy and the like.  I like all products from Zapco.  Lots of people like Alto gear.

Dyhon,

   What do you think about PPI's crossovers. Here is a link to the crossover that I am looking at right now.

    http:///.com/dll?ViewItem&item=5764537010&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

  Chris