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My cheap speaker project

Posted: September 20th, 2022, 2:07 am
by mix4fix
Tom has the "Eggs". Maybe, I should call them the "Toms". Tom gave me those Optimus/Lineaum bookshelf speakers. One of those funky tweeters was blown, and one of the woofers disintegrated. So, I started from scratch. I am using just the cabinet. They are not going to be great, but they will work.

I replace the woofers with some drivers I had. I didn't have the exact size drivers I needed, so I used something smaller that happen to work using a little ingenuity. The driver isn't screwed on, it is clamped on. I wish I could have the proper sized drivers. I don't really have the bass.

I used some ingenuity to take some tweeters and openly suspend them facing forward using the top grill mounts, as well as securing the wires before it goes into the cabinet. They look the part.

I wish I had some two-way passive crossovers to experiment with it. Right now, the drivers are wired in parallel without any crossover so the rear panel is removed with the wires sticking out.

Re: My cheap speaker project

Posted: September 22nd, 2022, 7:35 am
by Stuart Polansky
How about some pictures?

Re: My cheap speaker project

Posted: September 22nd, 2022, 7:49 am
by David McGown
Running a tweeter with no crossover is a recipe for blowing a tweeter. Just put a cap inline with the tweeter. For a 4000Hz crossover point using an 8 ohm tweeter, this is a 5uF capacitor. There are plenty of simple crossover calculators online if you do a Google search.

David

Re: My cheap speaker project

Posted: September 22nd, 2022, 9:40 am
by mix4fix
Tweeter is a Vifa 6 ohm. It has a 5 hole mounting, but only two are used to suspend it.

Don't remember what the other driver was. I would have to disassemble the cabinet to look.

Re: My cheap speaker project

Posted: September 22nd, 2022, 4:10 pm
by Stuart Polansky
So I guess that's a "no" to pictures. I was really hoping for pictures.

Re: My cheap speaker project

Posted: September 22nd, 2022, 5:49 pm
by mix4fix
Pictures to come.

I don't work on this everyday. I installed the mid-range driver long ago, and recently figured out how to mount the tweeter since these cabinets are unusual to begin with.

Re: My cheap speaker project

Posted: September 23rd, 2022, 12:12 am
by mix4fix
The mid-range driver is a Vifa 8 ohm.

Re: My cheap speaker project

Posted: September 23rd, 2022, 12:20 am
by mix4fix
Vifa 6 ohm tweeter, Vifa 8 ohm mid-range.

Re: My cheap speaker project

Posted: September 23rd, 2022, 8:32 am
by Stuart Polansky
Looks good. No surprise that there is no bass there.
If you can cut the lower edge of the tweeter and mount it closer to the woofer, that will help with phase near the crossover point.
But that tweeter will die a horrible death if you don't get a series capacitor installed to it.
You could fill those voids in the cabinet structure with a pour-in compound, that will tighten up the sound, reducing resonances.
A separate woofer in a different cabinet will be the best bet for real bass.

Good job!

Stuart

Re: My cheap speaker project

Posted: September 23rd, 2022, 8:42 am
by brombo
If you don't use a capacitor with the tweeter make sure the dc offset of the amplifier driving it is in the millivolt range.