My KLF 30 rebuild with pictures.

[shovelnose]

Hi all. So I bought these KLF-30's off a forum member here about three years ago. They had the Crites caps and ti-tweeters done all ready. So about a year ago one of the rear panel/baffle started to come loose causing vibrating cabinets with all the undesirables that go with it. So finally I decided to take the plunge and do a full rebuild/restoration. I thought I would post about it here because there is some info out there which I am thankful for, but I wanted to share my experience and maybe help someone out who is debating doing this. 

 

So about my self. I would consider myself pretty darn handy. My motto has all ways been if it's already broke I can't screw it up any worse, so I will tinker with just about anything. My woodworking skills are about average did some courses in high school by no means am I a pro. I would rate this project moderate in terms of difficulty. It's more take your time, measure twice and really think about what you are doing before you do it and things will go smoothly. I put about 30-35 hours into this project including stain and clear coat. Tools include saws, clamps, carpenters glue,(I used 2 full bottles) air nailer with 1 1/4" brad nails(Verify this so you don't go through you cabinet finish).  So here we go....

 

Obviously you start by removing all drivers x-overs and bass ports. To remove the panels people have used heat guns to soften the hot melt, painters tools rubber mallets ect. I used a rubber mallet and a folding utility knife. I ran the blade in the seams to cut the hot melt. Tap very lightly so you don't break the panels. I started with the backs just because you can get a mallet through the cut outs in the front. The front baffle is especially fragile because of all the cut outs so tap light people. If you hold your hand on the out side of the panel you are working on you can kinda feel where they are coming free because of the movement/vibration. Work your way around and it will come off. Take your time with this. You do not want to break a panel. I ended up chipping a couple small pieces taking them apart but glued them back together.

 

Once the panels are off it's time to clean up all the hot melt and Melamine. People have used dremels with a sanding drum. If you hit hot melt with the sanding drum it plugs up fast. Scrape all the hot melt off with a sharp razor. The folding utility knife was great for this. I also used it to get the majority of the Melamine off. I ran the knife at 90 deg and it flakes it right off with minimal smell and mess. Once I had the majority of it off I gave it a light sand with the dremel. As you can see my cabinets had minimal bracing some have none. But we are about to change that.

 

DRY FIT EVERYTHING BEFORE GLUING! Once glued it's permanent. Better to be a bit loose than tight. Glue will fill the voids. I either clamped or used air nails with the glue to hold things in place,

 

I started off using 1x1 spruce around the outer perimeter of the front and back where the panels will attach. This will give the panels tons to bite on when you re-glue them. I also used 1x2 spruce across the front panels between the woofer cut out and woofer/mid cut out. I used 1x 1 1/2 between the mid/tweeter cut out. This should give the panel some rigidity. Then I ran bracing 1x3" front to back  where the front panes have the bracing and side to side. Did I mention dry fitting before gluing? I used the small side of a wood shim just to make sure I had about 1/16" clearance. When you clamp the panels that space virtually disappears.

 

Part 2 below......

 

 

 

[shovelnose]

I also ran 1x3 front to back on the top and bottom of the speaker. Then I used 1x3 from the bottom to the top attaching and the bracing into 1. I also used blocks for a little more re enforcement for the top to bottom braces.

 

Did I mention dry fitting before gluing? Even insert your drivers and x-overs to make sure there is no interference. I had no issues but I am so glad I checked before everything.

 

Now that I am done the  bracing I started on the finish. Sanded cabinets with 220 grit sand paper. I went very unconventional with my stain of choice. I love it, you may not. 3 coats of stain then onto 10 coats of water based urethane. I sanded using a medium synthetic abrasive pad every couple of coats. Sand light. Just scuff. It's not hard to go through multiple layers of finish.

 

Now it is time to re-assemble. I did 1 panel at a time starting with the fronts. I used 1x2 boards (so as not to damage the finish) and 4 bar clamps. Use lots of glue but not to much. I had some squirt out the front of the panel. Pain in the but to clean and if it dries good luck. I left clamped for 8 hours. There are various times out on the internet. Glue says 2 hours so I did 8 just to feel safe.

 

Happy time! Time to re-assemble. Screw all drivers in the way you took them out. Tighten but don't over tighten, you don't want to strip screw holes. Hook it up and enjoy!

 

Side note. I lost about .46 cu ft of box space. I went a little over board but I was not concerned with low end bass. That's what subs are for. The bass is awesome now anyway. I'm not concerned with a few hz. Anyhow. I'm sure I've left some stuff out but I wanted to try to help a fellow speaker enthusiast out. Take a great speaker with poor glue and make it great again.

[SWL]

That's cool shovelnose. I've got two pairs of 30's and just got done sealing and rebracing my second pair. Both sets are done up the same way:

Titanium tweeter diaphragms
A55G midrange drivers
New crossovers from Bob Crites including new internal wiring
Sealed cabinets with PL Premium X3
Added front to back bracing

The additional bracing and making sure the cabs are sealed properly is huge. Bass response is improved drastically.

Just put these in my second pair today:



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[SWL]

Those look gorgeous!

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[SWL]

Mine are pretty much done. The next/last thing to do is refinish the cabinets.

Thanks for posting and I really like your finish. I might just follow in your footsteps on this.

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[CECAA850]

They look great.

 

Polyfill would help with compensating for some of the volume you lost with the extra bracing.

[Ceptorman]

Nice work, they look great, nice finish.

[richieb]

47 minutes ago, CECAA850 said:

They look great.

 

Polyfill would help with compensating for some of the volume you lost with the extra bracing.

 

I noticed the lost cabinet volume too, seems to be a fair amount. Explain how polyfill makes up for he difference. Seems like it would have the opposite effect and you would have even less volume?!

[jjptkd]

"When Poyfill is added to your enclosure, the airspring within the box begins an isothermal process. When the air passes through the Polyfill it is scattered and dissipated by the fibers, causing the air to be less dense. The speaker then interacts with the enclosure as if it is larger than it really is, changing the sound."

 

http://knowledge.sonicelectronix.com/car-audio-and-video/accessories-and-installation/what-is-polyfill/

[richieb]

^^^^^

+

[JDJohnson]

Great job!

[pzannucci]

9 hours ago, jjptkd said:

"When Poyfill is added to your enclosure, the airspring within the box begins an isothermal process. When the air passes through the Polyfill it is scattered and dissipated by the fibers, causing the air to be less dense. The speaker then interacts with the enclosure as if it is larger than it really is, changing the sound."

 

http://knowledge.sonicelectronix.com/car-audio-and-video/accessories-and-installation/what-is-polyfill/

Careful, it can reduce punch and maybe not work as you think in some speakers i.e. pretending your volume is back again.  Best to measure its affects on the tuning of the speaker (if you have something like wt3 or alike for the resonance/tuning dip) and listen to it with your chosen amp.  That will help you verify the results and help you decide best course of action.

[shovelnose]

Thanks for the kind comments everyone. I would have liked to have just left them with stain but wanted some protection. It was well worth the effort and I am pleased with the final result. In the future I plan to do a little work dampening the mids and tweeters.

 

On a side note is there a way I can move the pictures around so the match with the wording and not get listed at the end?

[SWL]

In the future I plan to do a little work dampening the mids and tweeters.

The A55-G midrange driver from Crites will accomplish this....and then some.


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[SWL]

http://www.critesspeakers.com/k-55-replacement-the-new-a.html

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[moray james]

Shovelnose: I want to congratulate you on a nice rebuild job. I also wanted to make an observation and don't want it taken as a criticism rather as a possible small enhancement for future builds or for others wishing to follow in your footsteps. 

   The braces used on your front baffle are mounted sideways and not as stiff that way as they could be had they been mounted on edge rather than on the flat as you have done. The design ratio for the most stiffness is 1:2.5 so the narrow edge would be one and the long dimension would be 2.5. This results in the best compromise. Making the brace wider only adds minimal stiffness and just eats up more internal volume for little return. So to recap if the thickness of your brace material is one inch then the width would be 2 1/2 inches mount the brace on the narrow one inch (in this example) edge. Regards moray james.

[shovelnose]

12 hours ago, moray james said:

Shovelnose: I want to congratulate you on a nice rebuild job. I also wanted to make an observation and don't want it taken as a criticism rather as a possible small enhancement for future builds or for others wishing to follow in your footsteps. 

   The braces used on your front baffle are mounted sideways and not as stiff that way as they could be had they been mounted on edge rather than on the flat as you have done. The design ratio for the most stiffness is 1:2.5 so the narrow edge would be one and the long dimension would be 2.5. This results in the best compromise. Making the brace wider only adds minimal stiffness and just eats up more internal volume for little return. So to recap if the thickness of your brace material is one inch then the width would be 2 1/2 inches mount the brace on the narrow one inch (in this example) edge. Regards moray james.

I get what you are saying. Constructive criticism is always welcome in my book. Too late now lol. I don't know if it makes any difference to what you are saying but the baffle pieces are also glued to the front to back braces and the 1x1 around the perimeter. In short it should be plenty stiff. But you are saying it would make a difference to turn them 90 deg still right?

[moray james]

The braced will be considerably stiffer on edge yes ( and yes even with the front to back struts) you could if you wanted to install some sections on edge to the cross baffle braces after the fact on either side of your front to back struts. Not sure if you would notice a big difference but it would stiffen the baffle and that is always a good thing. I cross brace below between and above the woofers and I even throw a cross brace between the mid horn and the tweeter. On the back with a passive I brace below and above the passive then go vertical from there usually one on each side of the terminal cup from the top of the passive to the top of the cabinet and I place a single central vertical on each side and on the to front to back.