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MrCommunistGen
Feb 4, 2006, 12:18 AM
I figured this would be the best place to post this.
Intro: I'm not really into audio editing or composing though I do tinker with Amadeus from time to time. I'm into good audio on a budget... and I enjoy being creative.

Situation:
I have two pairs of stereo speakers, both Infinity bookshelves, each 2-way. They are both part of the same series, the recently replaced Alpha series and are the A10s and A20s respectively. One set of speakers has larger woofers than the other. I also have a stereo receiver... an Onkyo TX-8511. I would like to make it so that the smaller speakers handle the upper and mid ranges, and have the larger pair handle the bass. Effectively creating a 3 way system. The A20s are bi-ampable and the A10s are not.

Question:
Would the best way to accomplish my goal be a crossover? If yes, is there anyplace that you suggest for buying crossovers and what type/brand would you suggest? I was thinking of crossing the system over somewhere between 150-200Hz. If you have any ideas I would welcome them. The idea here is to not buy new speakers, but to mostly use what I have.

Thanks!
-mcg



beatsme
Feb 4, 2006, 07:16 PM
there's really two ways you can do this: you can use an "active" crossover, or a "passive" crossover.

A passive crossover connects between the amplifier and the speaker, and filters out any unwanted signals. For example, a 70Hz low-pass crossover would filter out any signal higher then 70Hz, and let all signals lower than that go through to the speaker. This is the quick and easy solution, though it wastes power because the signal has already been amplified.

An active crossover is an electronic device that separates the signal after the pre-amp stage but BEFORE the amplifier stage. This is generally the better way to go, though active crossovers are pretty expensive.

Check out crutchfield.com. They have a pretty good primer on crossovers and how they work.

hope this helps

MrCommunistGen
Feb 5, 2006, 03:40 PM
Definitly looking for a passive crossover. I'm looking to spend as little as possible. I'm having trouble finding a place to buy the kind of crossover I want. Most of the 2 way crossovers I've seen have a crossover point near or above 2kHz which is about where the speakers are ALREADY crossed over. Also, revision: I'd settle for a crossover in the 250-500Hz range...

I've done quite a bit of Google-ing and am getting pretty frustrated whenever I see a crossover that might be appropriate (based on the speaker that it was pulled from) the crossover frequency is not listed!!! :(

Thanks!

howesey
Feb 5, 2006, 05:46 PM
You will have to have the same x-over frequencies unless you want to make a new cabinet - you'll need to move the drivers closer or further away. The drivers are a set distance apart from the edge of the cones depending on the x-over frequency. The cones are also designed to work at a certain xover frequency as well.

X-overs are very complicated. Different designs and components sound different so you will have o experiment making them sound good.

MrCommunistGen
Feb 5, 2006, 06:23 PM
I think you may be misunderstanding my situation ;) . I'm planning on using the two sets of speakers, both still in the original cabinets. I'm not tryng to switch the crossovers inside the speakers, I'm trying to set up a crossover between the two sets, with the smaller speakers acting as the high frequency driver and the larger speakers acting as the low frequency driver. Also, after generating some waveforms I've decided that a crossover at or below 250Hz is probably what I want...

My main problem is that most of the crossovers listed on the net don't actually state their crossover frequencies! :mad: and that most 2 ways have fairly high crossover points. Some X-overs listings have resistor specs, but I have no idea how to interpret these.

Anyone know of a good audio forum I could post on? I searched for one and didnt really find much.

Thanks
-mcg

beatsme
Feb 5, 2006, 07:22 PM
http://www.crutchfield.com/S-zHRv0PQh8HO/cgi-bin/ProdView.asp?wm=fp&I=069900064&g=82600

The link above is for passive crossovers which are designed for use with car stereo applications. But, since they use RCA connectors, what you could probably do is head out to Radio Shack and get some speaker wire that has two tinned wires on one end and an RCA plug on the other. See it below:

http://www.radioshack.com/product/index.jsp?productId=2102959&cp=2032058.2032227.2032241&pg=2&parentPage=family

with the right adapters (you'd probably need some female-to-female RCA adapters) and a little jury-rigging you might be able to get this configuration to work. Actually, I'm willing to bet it would work...

hope this helps

MrCommunistGen
Feb 11, 2006, 12:43 PM
I think I'm going to table this one for a while... I've reasoned that the RCA style crossovers would probably work best out of what I've found so far, but the cost would be rather prohibitive. I would need a high pass and low pass model along with two of those RCA-to-bare wire cables for each channel... for that kind of money I should just invest in better speakers... or just bring my big speakers from home to college :D

-mcg