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Klipsch KLF-30 rebuild starting today...


avguytx

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Today marks the day for at least starting the rebuild on my KLF-30's.  Drivers, crossovers, insulation, and ports are out (ok, they're still in on one picture :D ) but you get the idea.  Here are the plans...

 

  • Remove back baffle and re-attach with 1 x 1 bracing on edges, liquid nails, and 1-1/4" wood screws.  (not going all out here as I just had carpul tunnel surgery 5 weeks ago, a cyst removed, and a bone spur removed on my index finger all on my right had...gets sore pretty quick)  Also do the same strips on the front baffle from the back side.
  • Brace front to back underneath the tweeter, mid and between the woofers and also side to side bracing around 3/4" x 4" strips.
  • Add some density to the top and bottom of the cabinets....maybe 1/2" MDF or plywood for solidity.
  • Add a vertical brace from top to bottom that's also attached to the cross braces.
  • Lightly sand down the cabinets, fill in any voids and rebuild edges where needed then apply Valspar  Satin Black paint.  I also have some Valspar Premium Finish Micromist spray but will test that on the bottom along with the satin black paint.  
  • New caps and resistors on the crossover networks.  I didn't get a new 97mfd cap, yet, but will pop up a leg and see what it measures.
  • Use some "Fat Mat" (like Dynamat Pro...I already have it) on the mid horns and sections of the woofer frames.
  • Lining the inside cabinet walls with better insulation.

I'll most likely order the Titanium diaphragms for the tweeters next week but will leave the phenolic diaphragms in the mids for now.  I removed them to see what versions were in the mids....not Poly.  At some point, I'm going to mess with the cabinet tuning since I have a Tune Port Generator (Rockford OSC-2) and can tune them based on the cabinets in my actual living room in the "hot spot". The port openings in the cabinet are about 4-1/4" but the ports themselves are 3" inside diameter so this gives some room for tuning since I can go to larger ports.  I wonder if the T.S. parameters for these woofers are out there somewhere?  Wasn't it mentioned that these were/are used in the Jubilee's or am I completely wrong?  

 

Ok...time to get started.

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Edited by avguytx
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I bought a 12" x 4' piece of 3/4 oak and diced it up on the table saw to 3/4 x 3/4. With the 3/8 lip already on the cab it gave plenty to attach to. I also used clear silicone on the strips just before screwing them down and also just before screwing the baffle and back board on. sealed up nice and tight.

Also added a after picture of the baffle screwed on. :)

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Edited by cradeldorf
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My bracing will be similar to that but also adds front to back baffle bracing. I decided not to take off the front baffles but will add the 3/4" strips all the way around them and liquid nail/screw them in place Just like reattaching the back panel. Will be a tad tougher than my CF-3's that have removable front baffles that screw in place with 6 screws behind the grill peg holes. But no biggie. I have a right angle attachment for my cordless drill for those. My arms areally a little sore from yesterday's scraping of old glue and I have one more back panel to remove but I've scraped off what I could inside the cabinet and ran a razor down the channel from the back side and also used a thin scraper.

Edited by avguytx
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Lining the inside cabinet walls with better insulation.

 

This is the part of your build I wonder about.  Not because I know something better, but because I don't know, and I wonder about it.

 

Did your KLF-30 come with the ubiquitous Klipsch 3/4" foam sheets? (or two together)  On my CF-4 the sheets are placed in three sections, deliberately but loosely, and it looks like it would break up standing waves, but not really damp anything.

 

I was trying to tame a harshness in the HF sound which I did by replacing the bottom of one of the 3 sections of foam with some polyfil.  I am always cautious with polyfil because I don't want to damp the sound too much and deaden the aliveness of the sound.  The problem IMO is that this is more trial and error than "one size fits all."

 

Are you going to use the popular denim insulation for lining the walls?  Or will you be going your own way on this?

Edited by wvu80
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I'm not sure on the insulation part just yet...I may try some different things. These have 4 pieces of the 3/4" foam per cabinet that are about 1' x 2' and were held down with 2 staples each. they were all towards the top and none at the bottom.

I used polyfil for years and years when I was in car audio for sub cabinets...especially for sealed cabinets. For ported, they usually didn't need it as you didn't want to alter the tuning frequency, but, they were crossed over a lot lower; 80hz give or take. Home speaker woofers are crossed over a lot higher since they're in 2 or 3 way speakers. I'll probably use the foam on top and something else on the bottom to dampen any lower mid sound coming thru the ports.

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Yesterday I was able to work on one cabinet a little more in between having to help my wife with"her" project.  I still need to remove the back panel on the other speaker but at least it's mostly loosened except for applying some heat to finish it off.  The front and back panels are secured with the 3/4" x 3/4" strips all the way around and glued, siliconed, nailed and screwed in place as is the back panel.  The melamine was sanded off about 1-1/4" in to bare wood for glue adhesion and then wood glued, siliconed, nailed and screwed in place like the other; it's not going anywhere.  The wood glue was used on the flat section where the back panel meets the cabinet and the outer lip was siliconed for the heck of it.  I meant to take a picture of that but forgot so I'll do it on the next one.  Also, there are cross braces from front to back and side to side and  they connect together in the middle.  Yes, all of the drivers clear the braces.   :D

 

That may be all I get to do till next weekend...regular family life duty back in effect for the weekdays now.  Titanium diaphragms were ordered this morning from Bob, too.

 

Oh....can someone with a pair of KLF-30's maybe measure the depth of the ports or pull them out and take a picture of them?  I want to compare them with what mine have.  Maybe all of them use a 4-1/4" port cut out then flares down to a 3" i.d. port inside the cabinet.  I'm going to change them to a true 4" port and retune the cabinets using a tone generator instead of just tinkering with adding paper.  

 

 

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Titanium diaphragms came in today from Bob...dang that was fast. But I guess when you're an hour and a half away, it works out well. Won't get to work on them till the weekend though. Maybe I'll be able to hear one of them.

Edited by avguytx
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Finished other speaker today and swapped out the poly tweeters for the titanium domes. I had to go to father in laws birthday this afternoon and then its been storming some so I guess that's it till next weekend. So nothing new for pictures thus far. Hoping to get cabinets sanded down and repainted next go round and then work on crossovers while they are drying. Cabinets are definitely more solid so I'm hoping this improves them.

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One crossover recapped tonite. Forgot to take a picture but will add one tomorrow. Not that most everyone hasn't seen a recap before. ;) I used Axon caps and Mills resistors this time instead of my usual Solen caps. Parts Connexion was/is running them for half price and I've used them in the past with good results.

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  • 2 weeks later...

KLF-30's are finished enough that I can get them back in the living room.  The tweeter diaphragms were changed to titanium versions, cabinets braced/glued/nailed/screwed/etc, I moved the (4) foam pieces per cabinet more towards the bottom versus where they were at the top and stapled them into place, sanded and repainted cabinets back to satin black with the Lowes Valspar Satin Black (turned out very nice).  I still need to recover the grills, get new screw in feet for the bottom since they're just open holes except for the little felt pads I put on them for going on our wood floors.  I didn't get around to damping the horns and woofer baskets but that's no major deal to go back and do.

 

Highs sound nice with new tweeters, midrange still overly dominant like before, and bass might be a little better...but not much.  I think it's just these don't work well in the living room and that's it.  The CF-3's sound better, as do the Norman Lab Model 9's and my (sold off) Polk SRA SRS 2's.  I'm going to try them at a friends house on his setup and see how they do there. I'm not going to reinvent the wheel trying to make something sound better in a room where they apparently don't.  Some music you can listen to and they sound really impressive and then other music just sounds unbearable.  And on the music that sounds unbearable, sounds fine on the CF-3's.  They may end up going away in the near future and I'll just use those funds towards something else.  Or, I'll stick them in our bedroom or in the closet for another time.  Maybe a pair of Cornwall's or La Scala's will turn up.  

 

I'm still wondering if maybe the mid diaphragms were replaced with something sub-standard and they didn't mate up well.  But that doesn't explain their bass inefficiency.

 

But it was a fun project as always.

Edited by avguytx
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Wow, that sound almost unreal that you can't get the KLF-30's to sound any better than that.  You certainly did all your homework, you replaced XO parts, tweet diaphragms, I don't know what else you could do.

 

What are your ears telling you?  Is it just the weak bass?  I've heard of speakers sounding flat/dull because of reversing polarity in the tweets/mids, but I've never heard of that for bass.

 

How about your listening volume?  Are they the same from low/mid/loud, or do they really sing when loud?  How is the quality of sound, ie, does a female vocal sound full and clean, or shrill?

 

I hate to see you put away some speakers you've put this much work into. 

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Yeah, it was kind of disappointing for them not to sound that much better than they did before hand but I wasn't sure what to expect.  Once I saw how little of glue was holding the panels I was kind of hopeful that there would be a difference.  My ears tell me the midrange is too dominant and an RTA says the same.  I may try reversing the phase on both and see what happens.  They were wired correctly per the terminal markings on the crossover boards.  I might even reverse the woofer phasing on one side and see what happens.  I do know the sound of drivers being out of phase sounds like as I spent many years building and tuning high end car audio vehicles plus was a certified SQ judge....when it meant something.  And all the years of home A/V work, too.  

 

Let's say I'm listening to Allison Krauss.  Well we all know her voice has a nasally kind of sound occasionally but, on the KLF-30's, it's almost overbearing and I take the mid control down about half way to make it tolerable.  Never have to do that with the CF-3's or others.  Then most any well recorded CD sounds great on the CF's but lacks that same mid bass/low bass definition that the CF-3's, and others, have.  I keep thinking phasing on the woofers and it seems like I did reverse one side and it sounded like a$$ but I forget.  Not a big deal to pull and switch for short term.  It they were truly  out of phase, I could hear it....it stands out like a turd in a punch bowl.  I was in a local home/car A/V dealer over the weekend and I could hear the radio playing from one of there display rooms was wired out of phase.  There's just a distinct sound...or lack of....that it sounds like.  Borderline annoying.

 

I don't play crazy loud because I'm married and have two kids....and no dedicated room.  But I gave them some volume and they do sound quite good up loud IF you've got the Loudness on and the midrange control  backed down.  If I happened to be using my completely rebuilt Carver C-1 with no mid control, I'm afraid they'd really be awful.

 

They'll stay in the living room for a tad longer as I'll give them time for break in on the tweeters and caps....which isn't that long.  I'll try reversing the phase on the mids (both sides) and then reverse the woofers phasing (one side) and see what happens.  Otherwise, they aren't looking like keepers.

Edited by avguytx
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KLF-30's are finished enough that I can get them back in the living room.  The tweeter diaphragms were changed to titanium versions, cabinets braced/glued/nailed/screwed/etc, I moved the (4) foam pieces per cabinet more towards the bottom versus where they were at the top and stapled them into place, sanded and repainted cabinets back to satin black with the Lowes Valspar Satin Black (turned out very nice).  I still need to recover the grills, get new screw in feet for the bottom since they're just open holes except for the little felt pads I put on them for going on our wood floors.  I didn't get around to damping the horns and woofer baskets but that's no major deal to go back and do.

 

Highs sound nice with new tweeters, midrange still overly dominant like before, and bass might be a little better...but not much.  I think it's just these don't work well in the living room and that's it.  The CF-3's sound better, as do the Norman Lab Model 9's and my (sold off) Polk SRA SRS 2's.  I'm going to try them at a friends house on his setup and see how they do there. I'm not going to reinvent the wheel trying to make something sound better in a room where they apparently don't.  Some music you can listen to and they sound really impressive and then other music just sounds unbearable.  And on the music that sounds unbearable, sounds fine on the CF-3's.  They may end up going away in the near future and I'll just use those funds towards something else.  Or, I'll stick them in our bedroom or in the closet for another time.  Maybe a pair of Cornwall's or La Scala's will turn up.  

 

I'm still wondering if maybe the mid diaphragms were replaced with something sub-standard and they didn't mate up well.  But that doesn't explain their bass inefficiency.

 

But it was a fun project as always.

[/quote

Quote " I moved the (4) foam pieces per cabinet more towards the bottom versus where they were at the top"

Reflex cabinet vents work on resonance, they need a volume of open cavity space to resonate so as to couple freely between the woofer(s) and the vent(s), the woofer drives the vents and the vents load the woofer and the resonating air cavity make that happen. It would seem counterproductive to reposition the cabinet damping foam which had been factory installed in the top portion of the cabinet down lower in the cabinet toward the vents. I have found also that seemingly small adjustments to the mid can impact bass quality dramatically, horn wall resonances and any other mechanical resonances in the same frequency range such as woofer basket resonances or any other free to resonate component can have a negative impact upon the sound as a hole. Keep at it and get it figured out, it does not sound like a room issue.

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