passive crossover for subwoofer

[Jim O'Dell]

I'm looking for information on building a cheap passive crossover for a 10" dual (4 ohm) voice coil subwoofer for the shop stereo, to roll off around 150 to 200 hz.. I searched the net, but I mostly get theories that are a bit above my head, or articles on building the sub box, not the crossover. I was hoping to find a site, or online program that would tell me what size coil to use, and what else I might need and a quick diagram. I evidently didn't keep any of the coils from my stereo days, or I'd play with some until it sounded ok.
If you know a site I can go to, I would appreciate it. This is going to be a low power system, and I'm just looking for a little boost in the low end to compliment the small 2-way bookshelf speakers I'm using now. Thanks! Jim.

[Al Willits]

Try the Sound and Vison forum, there's a couple of regulars there that know how.

Not sure if I can post the web site or not, PM me if ya can't find it
Al

[Jim O'Dell]

Thanks Al! I found a site with the calculator I needed, now I need to see where I can purchase them. Hopefully Radio Shack has them, if not it will be a trip east to Arl to the Frye's Electronics store. I just hate using that much gas for this! :D Jim.

[Matt Meiser]

Jim, way back I bought some stuff from Madisound which was well recommended back in the Usenet days.

http://www.madisound.com/index.html

[Jason Beam]

ahh ... the joys of winding coils ...sounds like you found the calculator for the number of windings to use for your desired frequency cut.

Radio shack used to sell some that dropped off at about 200hz way way way back in the day ... for like $10 bucks ... i wonder if they still have 'em.

[Tim Morton]

You want to roll the sub off lower than 150, even in a shop stereo. Go for 100hz or lower, and you can do it with a simple coil. (6db). Or check out Parts Express for something pre-made

http://www.amazon.com/100-LOW-PASS-OHM-CROSSOVER/dp/B0002ZPPR6

How are you powering the sub?

[Jim O'Dell]

Jim, way back I bought some stuff from Madisound which was well recommended back in the Usenet days.

http://www.madisound.com/index.html

Yes, I found them during one of my searches. I have them marked as a possible source.


ahh ... the joys of winding coils ...sounds like you found the calculator for the number of windings to use for your desired frequency cut.

Radio shack used to sell some that dropped off at about 200hz way way way back in the day ... for like $10 bucks ... i wonder if they still have 'em.

No, I didn't find that calculator, Jason. I found one that you plug in the ohm rating of the speaker, then what frequency you want it to roll off, and it gives you the value for the coil. Do you know of one for "rolling your own"? :cool: I'd be interested in the possibility. At least to see the difference in price, and if it would save any money or not.


You want to roll the sub off lower than 150, even in a shop stereo. Go for 100hz or lower, and you can do it with a simple coil. (6db). Or check out Parts Express for something pre-made

http://www.amazon.com/100-LOW-PASS-OHM-CROSSOVER/dp/B0002ZPPR6

How are you powering the sub?

Tim, like I said, this is a low power system. It's an old stock stereo out of a Mazda RX-7. AM/FM, separate tape deck (yes, cassette:D ) and 2 separate amplifiers. Probably 20 or 30 watts each. The main speakers I'm using are a couple 2-way mini bookshelf speakers, 4" woofer, and tweeter. It gives really good bass for the size. Being that they are 8 ohm speakers, on a 4 ohm system, the 4 ohm sub will get twice as much power as they do. I hooked it up with an old Sony component car speaker crossover, and it had good volume to the sub, it's just it must have had a 2500hz or higher roll off. Way too much voice. The Kenwood crossover I found in the junk box says it's 3000, so I know that won't work. Might be fine for a set of midrange.
Anyway, I was shooting for 150 to help boost the bass of the small speakers a little. Doubt that I have enough power to get enough at 100hz or below to be able to hear it.:D I have the subs in my van crossed at 80 on the sub out of the EQ. They do fine, but have about 135/channel. Won't split the ear drum, but gives a nice deep bass boost for the 6" separates.
Thanks for the help everyone! I'll go look at Parts Express to see what they show. Jim.

[Al Willits]

Built my garage three way system speakers from Parts Express, probably ordered a couple/three of grand from them with no problems, I wouldn't hesitate to use them again, and will be when I build my next set of speakers.

Al

[Brian Weick]

I'm looking for information on building a cheap passive crossover for a 10" dual (4 ohm) voice coil subwoofer for the shop stereo, to roll off around 150 to 200 hz.. I searched the net, but I mostly get theories that are a bit above my head, or articles on building the sub box, not the crossover. I was hoping to find a site, or online program that would tell me what size coil to use, and what else I might need and a quick diagram. I evidently didn't keep any of the coils from my stereo days, or I'd play with some until it sounded ok.
If you know a site I can go to, I would appreciate it. This is going to be a low power system, and I'm just looking for a little boost in the low end to compliment the small 2-way bookshelf speakers I'm using now. Thanks! Jim.

Hi Jim,
Try this for parts http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=260-150 and try this for information http://www.crutchfieldadvisor.com/ISEO-rgbtcspd/learningcenter/car/crossovers_faq.html I hope this helps - Any Audio equipment store will be able to have an answer for you without having to take a rocket science coarse, unless you really want to understand it in depth.
Brian

[Matt Meiser]

Parts Express is good too. I've bought from their store in Dayton. They are connected with a REALLY cool surplus place called Mendelsons. I can spend hours in there.