Breck
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Posts posted by Breck
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Final product, bittersweet ending because i really enjoyed this project. Many thanks to all that offered your technical advice it was really helpful. Enjoy the pictures!
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Hit it with about 10 coats of tung oil with #0000 steel wool. That finish should glow with a shine that goes deep.
I love the hand wiped look of Tung oil but I'm not sure how scratch resistant the oil will be. Would hate to ruin the beautiful stain work.
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More Pics
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The home stretch; crossovers complete, horns, motors, and spiders insulated. Mahogany stain applied today, new grill cloth and topcoat next weekend. Debating between lacquer and water borne urethane. And by the way, they sound AWESOME! Decided to leave ports on the rear, bass response is super, slightly reducing the cabinet volume had no negative effects. In reality the cabinet is huge so there is more than enough breathing room in there. Attached a couple pics of Norm Cerveny completing the final touches, this guy is amazing as well as some before and after shots.
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We have a winner. Mahogany gel stain.
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I have a pair for sale but nobody wants them because I took the plastic rings off the woofers. $400.00
Do you have any pics? I may be interested.
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Seamless front & back baffles, also added casters that can easily pop in & out for mobility. Guessing they will weigh in around 145 pounds.
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Nice grain. Gonna start tuning this weekend.
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Veneer applied turned out nicely.
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Have you modeled the woofers with that much volume gone? What is your interior volume after removing about 1 cubic foot or so? It appears you are raising the box frequency dramatically.
If you are using a sub for the low bass and/or not using the KLF-30 woofers, you will likely be ok. If not you will have an interesting proposition on your hands.
According to my calculations the added interior thickness and bracing removes .9 cubic feet. With the acoustic dampening that I will be using will add roughly .5 cubic feet, for a net loss of .4 cubic feet. Negligible in my opinion. With proper tuning I think it will be fine.
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Using dowels for the baffles.
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Added 3/4" to the interior with center brace
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Cabinet takedown
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correct those useless ports
I'll be following this thread as I have two pairs of 30's.
As far as the ports....I modified mine (super easy) after extensive experimenting with lengths varying from 5" all the way up to 18". I settled on 18" ports.....10" sticking inside the cabinet and 8" sticking out. Probably sounds strange and I was hoping something like 5" or so would be what I would settle on but the best results kept going back to the 18" port (10" in 8" out of the cabinet). Maybe it's a room thing...distance from the wall etc. but it was easy and fun to experiment with. Not to mention it improved the overall sound of the speaker.
Did the longer tubes effect the bass response?
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Good luck on the design.
I would be considering adding some volume to a KLF 30 vs removing. Since the ports are to the rear, you wouldn't notice the mid-range bleed through unless you specifically tested for it with everything else turned off. The fact that they are in the back and minimal enclosure stuffing will tell you right there though sometimes that bleed through can make the speaker more appealing.
If you are dropping the size, you will be dropping the port size or making them longer. If the ports are facing the floor then that will be helpful in removing any unwanted wind noise or mid output.
You must be going to use these with a sub, correct? The 30s don't get super deep as it is with their small enclosure.
I would be looking at larger enclosure with somewhat lowered tuning, and if you are doing a crossover, adding an 8" mid bass or possibly 2 6" to clean up the discontinuity between the mid horn and the woofers. That would address the KLF 30's weak points.
Thanks for the tips. Was hoping that a major dose of acoustic dampening will address the slightly smaller enclosure issue. With regards to bass, this whole re-design is an effort to squeeze out a bit more bottom end thump. Will coat the spiders and anything else we can come up with. Last resort will be replacing or adding drivers.
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correct those useless ports
I'll be following this thread as I have two pairs of 30's.
As far as the ports....I modified mine (super easy) after extensive experimenting with lengths varying from 5" all the way up to 18". I settled on 18" ports.....10" sticking inside the cabinet and 8" sticking out. Probably sounds strange and I was hoping something like 5" or so would be what I would settle on but the best results kept going back to the 18" port (10" in 8" out of the cabinet). Maybe it's a room thing...distance from the wall etc. but it was easy and fun to experiment with. Not to mention it improved the overall sound of the speaker.
Norm is considering down firing the ports since I have carpet in my listening room. Not sure what the distance from the floor will eventually be. Gonna post some pics this weekend.
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Hmmm, I'm probably clueless but who is Norm Cerveny and why would his crossovers be better than others?
BTW, the ports aren't useless though you might not like them, they are for specific tuning and angling out the back to likely avoid mid-range bleed through. What size internal enclosure volume are you intending on using and what cabinet tuning frequency along with size of port(s)?
Norm Cerveny is a custom speaker designer whose designs have won several national competitions, your ears will tell you why his crossovers are so acclaimed. Never had a problem with bleed thru even when I experimented with closing the ports all together the k-52 really pushes hard. Enclosure will be 3/4" smaller, haven't gotten to the tuning yet but we are getting close still working on the cabinet. Definitely will post when tuning is complete.
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Came across a set of 30's for the right price so I decided to attempt a ground up re- design in an attempt to finally squeeze from this speaker the bass it SHOULD be producing. Although I currently own a pair of KLF 20's and a pair of KLF 30's, I couldn't pass these up at the price point I STOLE them at. Planning to reinforce the cabinet to the tune of 1.5" mdf ( box-in-box) with all the proper dampening, insulation, bracing, etc. Cabinet re-tune, correct those useless ports, and in all likelihood will try a non-crites crossover custom built by Norman Cerveny Pro Audio. Will refinish the outer cabinet as well with unfinished wood veneer with many coats of Hi Gloss lacquer, haven't decided on a stain color yet. Although KLF 30 mods are fairly standard these days, Norm Cerveny will be doing these from start to finish since this will be more than a simple modification.
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Planning to reinforce cabinet to the tune of 1.5" mdf with all the proper dampening, insulation, bracing, etc.
Reinforce, how? Do you mean building a box-in-a-box?
If you are wanting to do a stringer, I might suggest using a hardwood. MDF is really just sawdust and not a good material for a making a strengthening spine.
Box in a box with bracing. Gonna apply new veneer as well with a couple of coats of lacquer.
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Need a single K-52 driver and horn for KLF-30 rebuild. Came across a set of 30's for the right price so I decided to attempt a ground up re- design in an attempt to finally squeeze from this speaker the bass it SHOULD be producing. Although I currently own a pair of KLF 20's and a pair of KLF 30's (love these monsters) I would rather not pull a driver from either for this rebuild. Planning to reinforce cabinet to the tune of 1.5" mdf with all the proper dampening, insulation, bracing, etc. Cabinet re-tune, correct those useless ports, and in all likelihood will try a non-crites crossover custom built by Norman Cerveny Pro Audio. Will refinish the outer cabinet as well. Anyway one of these new old 30's as purchased contained a Selenium mid driver attached to a cracked horn. Certainly not complaining with regards to the Selenium squawker but I have a set of Ti's I would like use. Will trade the Selenium if necessary. Although a KLF 30 rebuild is fairly standard these days I am fairly anxious haven't done one in years.
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KLF-30 Redesign
in Technical/Restorations
Posted
Next at bat, project KLF-20.