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Kenwood LS-408B 12" 3 way info?

absolve2525

absolve2525

Super Member
Kenwood LS-408B 12" 3 way info? Now with photo below

Big Tuna? I just bought a pair, but the tweeter is bad in one. Fortunately, i have a pair of smaller LS series Kenwoods with the same tweeter and swapped out the pair. Does anyone know what the resistance should be on these tweeters? Ill most likely get parts express phenolic tweeter replacements since they sound great. Thanks.
 
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Here is a photo along with my Realistic STA-220 looming in the background.
 

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Yeah I agree Nick - the whole LS-40* line is pretty sharp. Fortunately this pair isnt too beat up at all. I have the smaller 2 way with a 10" and its amazing. I got lucky enough to find this top of the line model on Ebay for a great deal and the seller was kind enough to ship them. With a bad tweeter - but oh well, I had a spare available.
 
Whoa! You got me drooling terribly, Adam! ****EDITED BY MODERATOR**** Resistance, by that I'm assuming you are wondering what the ohm reading should be on it. Should be around 4.0 to 6.0 Ohms on the DMM. any lower than 2.0 and you have a dying/about to be dead coil on your hands. Did you match the new caps values as closely as possible to the original caps when you replaced them? The mids are crossed over a bit on the high side, mainly to eliminate cone crying, overtones, and heavy coloration. I have found a factory intentional mistake with the pot adjustments for the mid & tweet on the baffle. They installed the knobs 1/3 too bright, in other words, the knob was not installed on pole with the pot the 50/50 neutral position. If you remove the knobs, and re-install them in the neutral position and leave them there, you will find they will sound much better. You can find the neutral position of the pot by rotating it all the way (-)counter-clockwise direction until it stops, partially install the knob with pointer at 7pm(using clock as reference point) position, then rotate back around until it stops at other end. Pointer should be at about the 5pm mark. Push knob all the way back on post & You then will have pointer set to "neutral" and you can leave it at the "0" mark which will make the tweet & mid softer than the harsh factory setting. Oh, and the factory also installed the mids polarity reversed. If you take mid out of baffle and reverse wires to have them "in phase". the wires to mid are brown and green. The green one is the negative and brown one is positive. Install them in phase, set the pot knobs to neutral and you will be pleasantly surprised. let me know how it turns out. If you need step by step instructions with pics to help you better perform my revisions, let me know. :)

Charlie
 
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Charlie! Thanks my man - I've been pondering the last few days why the mid sounds overbearing at the normal level position. I did replace the caps with a 3 and 8mf Jantzen polyprop caps as they were originally in the speaker. Thats interesting that you mention the mid is out of phase; I'll have to hook it up in phase and listen. What sort of resistance differences between a set of tweeters is considered acceptable? If one measures a little lower or higher, how noticeable is this? Thanks again, and if you have pictures regarding the wiring, that would be very helpful!

Kramer
 
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Your Welcome!
Anywhere from 3.0 to 6.0 Ohms on the meter between the two is considered fine. Are you using your STA-220 Realistic to power them? I will get some pics as soon as I can. :)
 
Right now I have the speakers hooked up to a vintage Hitachi PMA-6500 mosfet amp. Its 60 watts I believe. It sounds very sweet and open. I rotate around - I have a Kenwood 9g and a Pioneer sx-980 too. I havent tried them on the others yet. I have a pair of recently acquired Cerwin Vega AT-15s that are hooked up to the Kenwood at the moment. For a steal on Craigslist, I couldnt refuse these huge CV beasts lol.
 
Oh, Cool! Yep, I still have my AT-15's. They are about the most impressive stock CV I have ever listened to. Not over bearing or harsh at all. The bass from the AT-15's is just so strong and clear. No roll off whatsoever, where the D-9 and 380SE were not quite as strong.

Anyways, back to the LS-408B's, I also have the brochure and I can scan the pages for you to see if you like.
 
Sweet! Ive been really impressed with the AT-15s too - I actually got them around the same time the Kenwoods arrived via UPS, so my attention has been a little divided. I did play Terminator Salvation with the AT-15s and it kicked some major ass, withOUT bass boost! I can only imagine what happens when you boost the bottom octaves lol. It would be great to see the Kenwood brochures - I tried searching online for some, but didnt have much luck.
 
Well it looks like my level knobs were actually installed the right way, as you described. I found that tweeter level was fine at that "0" point, or 12 oclock, but it was the midrange that just didnt sound right regardless of the level. I opened them up and found that they were out of phase like you said! I'm going to reconnect them with the right polarity and do some listening. Thanks for the heads up! I kept shaking my head about that midrange not sounding right.
 
your welcome! :) ummmm, let's see, I have four 408B's, I had two pairs 407B, but now only 1 pair, 1 pair LS-405B, 1 pair LS-405A, 1 pair LS-403A, 2 pairs LS-403.


So, 10 pairs total :D

I also have 1 pair of the LSC(LSC-3000) series, which came later, and Kenwood also had the LSK-B series which were nearly identical to the LSC Series. They were the Acoustic suspension design, and from what I've been able to gather, those two series used the same mids and tweeters as the LS-Series.
 
After switching the leads on the midrange, and regluing the seals in the midrange chambers, I found a huge improvement! Much more full sounding and smoother overall. Thanks again Charlie for the suggestions! :D
 
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