Vintage Bogen LS20 Refurb
jdjohn
Posts: 3,388
I have a pair of very vintage Bogen LS20 speakers from my dad's collection that I want to refurb. Before you ask, "why bother?", this is primarily for wifey, who loves the vintage look, especially the grill cloth fabric. The cabinets are in good shape, along with being quite solid at 3/4" thick. The turquoise thread accent is really nice (and better in person), along with the metal strips that frame the grills.
I agree with her on the looks, but not the sound...even under the best conditions. In one of the speakers, the woofer voice coil is rubbing, and the paper tweeter cone has a tear. So, I'm considering replacement drivers, and a new two-way crossover. The original woofers are 8", and have DC resistance of 3.5 ohms. The tweeters are 3.5", and are at 8.5 ohms. Cabinet volume is about 0.81 cubic feet. These are sealed/acoustic suspension speakers.
So, without going crazy, I'm considering these woofers: https://www.simplyspeakers.com/replacement-speaker-woofer-w-208-4.html
And these tweeters: https://www.simplyspeakers.com/replacement-speaker-tweeter-t-145.html I would have to enlarge the cut-out in the speaker baffle very slightly, but that wouldn't be a problem.
Lastly, I would likely go with a pre-fabricated crossover like this: https://www.simplyspeakers.com/speaker-crossover-2-way-a-1302.html But, I need help on the crossover frequency options. The woofers have a range of 45-7000 Hz, and the tweeters go from 3.5kHz to 20kHz.
Thanks in advance for any advice!
I agree with her on the looks, but not the sound...even under the best conditions. In one of the speakers, the woofer voice coil is rubbing, and the paper tweeter cone has a tear. So, I'm considering replacement drivers, and a new two-way crossover. The original woofers are 8", and have DC resistance of 3.5 ohms. The tweeters are 3.5", and are at 8.5 ohms. Cabinet volume is about 0.81 cubic feet. These are sealed/acoustic suspension speakers.
So, without going crazy, I'm considering these woofers: https://www.simplyspeakers.com/replacement-speaker-woofer-w-208-4.html
And these tweeters: https://www.simplyspeakers.com/replacement-speaker-tweeter-t-145.html I would have to enlarge the cut-out in the speaker baffle very slightly, but that wouldn't be a problem.
Lastly, I would likely go with a pre-fabricated crossover like this: https://www.simplyspeakers.com/speaker-crossover-2-way-a-1302.html But, I need help on the crossover frequency options. The woofers have a range of 45-7000 Hz, and the tweeters go from 3.5kHz to 20kHz.
Thanks in advance for any advice!
"This may not matter to you, but it does to me for various reasons, many of them illogical or irrational, but the vinyl hobby is not really logical or rational..." - member on Vinyl Engine
"Sometimes I do what I want to do. The rest of the time, I do what I have to." - Cicero, in Gladiator
Regarding collectibles: "It's not who gets it. It's who gets stuck with it." - Jimmy Fallon
"Sometimes I do what I want to do. The rest of the time, I do what I have to." - Cicero, in Gladiator
Regarding collectibles: "It's not who gets it. It's who gets stuck with it." - Jimmy Fallon
Comments
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I'd think hard about the blending of an 8" woofer and a small dome tweeter. I would maybe just look at an 8" full range? That would eliminate crossover worries. Cost might be higher and you have to seal the tweeter opening or design it into a tuned port? Probably all more design headache than you are looking for.
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If you stick with a 2-way, maybe try to imitate the Mission 700 series driver and crossover design? I don't think you want 12bB sloped crossover on a 2-way with such a gap in driver size.
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I'd suggest the Dayton DC28F and a 1.5-2K Hz crossover. With a very low Fs, it's sure to blend with any 8" woofer much better.
The factory crossover sticker on those show 1100 HZ crossover.
Love the vintage resto-mods. Looks like real aluminum strips/trim in the baffles?
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