DIY - HornEd mod on KLF center channel

[wjfranke]

Ok, so I've had a spare KLF-30 sitting in my garage for the last year. I got some help from dbflash on my first KLF-30 conversion, and have finally decided to build the 2nd one and try to sell it. So, this thread is kind of self-serving, and those interested in purchasing the KLF-30 converted center can see how I built (er, converted) the thing. I had originally planned on a 6.1 setup, but just don't have the room, and I can't convince my wife that the 6th KLF would make all the difference. Besides, I have to admit that I'm quite satisfied with a 5.1 setup of KLF's all the way around.

So, first things first, pull the drivers & horns out, disconnecting all of the wires. I usually label the negative terminal on each one as I pull it, but all of the KLF's that I've looked at have the positive terminal labeled somehow (usually a colored dot that corresponds with the wire color). I've attached a quick picture.

[wjfranke]

Ok, the next thing to do once the drivers, horns, and crossover have been removed is to "remove" the motor board. This essentially calls for a slegdehammer (I used 4 lb). I hate to get mean with it, but the first KLF-30 that I converted was difficult (I took a break, had a couple of beers, and had success the 2nd time around). Luckily, this motor board came out much more easily. Notice the flakes of MDF from the old motor board still on the speaker. I used a chisel and hammer to remove this afterwards. Obviously, you can't get it perfect due to the remaining glue, but you can get it close. I'm just not a big fan of leaving the bits of MDF in there when you glue to new motor board in. Unfortunately, this takes time, but if you consider the many hours of enjoyment you'll get from the speaker, a couple of extra hours of effort to get it as good as you can is worth the time.

Anywho, here's a picture of the motor board removed and trusty 4 lb sledge.

[wjfranke]

Ok, another pic of the egdes in a "more cleaned up" state.

[wjfranke]

Ok, now starts the fun of trying to build the new motor board. Ok, many use a 3/4" MDF board, but when I built the first KLF-30, I could not find any at the local hardware store, so ended up buying some 11-ply birch at 3/4", and it worked very well. I found that the birch cut very easily (perhaps not as easy as the MDF), and was very firm. You'll need to measure the dimensions needed, and then I had Home Depot cut the pieces to size as I did not have a table saw. Once I got it home, I used an orbital sander, and cleaned up the edges all the way around.

Next, I tried to stay true to some of the original posts from HornEd. Put the HF horn directly on top of the mid-horn, and arranged in the middle of the motor board. The easiest way is to simply use the horns, and trace around the outside (note: I recommend NOT doing this with the drivers as they have a slanted outside edge). You should try to give yourself an extra 1/16" or so all around to be on the safe side. Attached a quick pic:

[wjfranke]

Ok, for the drivers, I used a compass. Basically measure the outermost edge of the driver. I think it measured about 12 3/4", so used the compass and made lines at 12 7/8" diameter. Be careful as the drivers barely fit in the motorboard (maybe ~1/4" on each side). Again, here's a pic:

[wjfranke]

This is the part that I'm not a big fan of. Routing.... I wish there was a better way to do this, but either I'm not smart enough to think of it (quite possible) or I simply don't have the tools to do it. So, you pretty much have to rout the edges by hand eyeballing it as closely as you can. I'm not exactly a surgeon, but go as slowly as I can. I highly recommend using hearing protection and safety glasses while routing. I also highly recommend good router bits. If you shop at home depot, get the Porter Cable bits. They're expensive, but the cheap bits burn up and don't cut nearly as smoothly. I used a 5/8" router bit, and set the depth at 3/16". And another pic:

[wjfranke]

The next part is to rout through the motor board so the speakers will fit in. Oddly, it's close to the line of the 5/8" router bit that I used for the countersink. So, I simply follow the line that I previously routed. You'll need to measure the diameter of the lip that is needed, but you want as much as you can get as you'll have to screw the speakers in later on. The drivers had about 3/4" of lip, and the mid/HF horn had slightly less (maybe 5/8"). Ok, another pic:

[wjfranke]

Once everything was routed, the first thing to do is test fit the drivers. Just make sure that everything fits. Next, I used a piece of sand paper to smooth out rough edges by hand. I didn't want to take off much material (I worked so hard to rout it carefully), hence not using the orbital sander.

Now, we're on to glueing it into the case. The KLF speakers are known for having poor glue (rattling), so I reinforced all of the edges where the factory glue was not visible. I used liquid nails for this. Another pic:

[wjfranke]

Now you're ready to glue the motor board in. Again, a healthy bead of liquid nails all the way around. I kept the chisel close by to position the motor board so that the clearance on edges was pretty even. Then add some weight on top (paint cans work well), and give it 24 hours.

I'll finish posting everything tomorrow or Wednesday. I'm sure this is "old hat" to most of you, but I was pretty tentative the first time around, so a thread like this would have been gold to me. Of course, if anyone has a better way for doing something, please feel free to post it.

One more pic:

[DrWho]

nice work [Y]

It's been awhile since I've heard the HornEd mods mentioned. Good luck selling.

[dbflash]

very nice and thanks for the pictures.

danny

[rcarlton]

Nice looking work. The speaker brings back fond memories of my old KLF-30's.

[SCOOTERDOG]

welcome to the world of big bad custom centers. I also, as a few others have built custom centers based around the KLF30. I for one used the midrange driver out of a klf 30 and then a T35 tweet all mated to a couple of 10" kv 1089 woofs. Once you hear it you will want to keep it and hold it and sing happy songs to it. Although I built my cabinet completely and not from a KLF 30...I took the hard road[]

[wjfranke]

Yes Ron, this is the 2ndone of your old pair. I'm extremely pleased with the first one that I converted. Listening to SACD's with good vocals is as close to Heaven as I could imagine. I also upgraded the x-over with one of popbumper's for the KLF's. I have KLF-20's for front's and rear's (front's have upgraded crossover from DeanG), but decided on the KLF-30 for center as it fit perfectly under my TV (50" LCD). I suppose one day I'll make the jump to K-horns, but I'm extremely happy as is. Besides, I think the wife would blow a gasket once she saw how big the K-horns are. She lost it when I brought in the SVS PB-12+/2 sub.

I suppose I'll need to update my auto-sig with the current setup.

[wjfranke]

Ok, It's been a while since I've posted. I managed to add the KLF-30 to the rear for a 6.1 system, but we're in a pinch on cash, and the wife has commented multiple times that we just don't need the 6th speaker. So, despite not agreeing with her, I have agreed to sell the speaker. A new HDMI 1.3A pre-amp is in my future plans, and as most know.......pick your battles. So, I'll post the remaining pics and give an explanation of the last few steps. I'll then post over in the home theater forum and hopefully somebody is interested.

So, with that said, I swapped the standard network with one of Popbumper's networks. I swapped them on my first converted KLF-30, and was very pleased. As you can see, it's significantly upgraded over the stock network. I've attached a pic:

[wjfranke]

Next step was to install the network. I skipped a few pictures, but the basics are that I painted the motorboard. Then used the grill to make a small indentation on the motorboard to rout holes for thefeet on the grill. I believe I used a 5/8" router bit. You'll also need to drill holes for the speakers in the new motorboard. Be careful as there may not be a lot of space, and you may need to drill at an angle.

Ok, so I attached a pic with the network installed and nothing left but the speakers to put in. You'll need to make sure that everything fits properly (mostly the woofers). If not, then hopefully a little touch up with sand paper or slight routing will resolve.

[wjfranke]

Ok, make sure that all of the foam is properly spaced in the box, and put the remaining drivers in.

See pic:

[wjfranke]

And last and definitely the most enjoyable was doing an A-B test with my front left KLF-20. I listened to several SACD's to confirm that it was working properly. Again, I love the sound of the KLF series, and a converted KLF-30 center definitely completes the system.

Last pic:

[jwc]

Since you are dissecting the KLF-30. Do you mind getting a couple of measurements for me.

The ports in the back. What is there exact length and what is the internal diameter?

Do you know what the internal dimentions of the cabinet are? Is the cabinet made out of 3/4" or 5/8" wood?

Thanks

jc

[wjfranke]

Actually, it's been put together now for ~5 months. I'll be going from memory (which is shady), but I remember that wood being 23/32" (or essentially 3/4"). As for the ports, they are about 2" long each, and the ID on them is ~3.5" or so. Keep in mind that the ports are slightly different depending on what year the KLF's were manufactured. I have an older pair of KLF-20's, and the ID on the ports is slightly larger (likely over 4") AND the length is shorter (again, going from memory). The converted KLF-30 was manufactured in 2001.

Again, this is going from memory, but hopefully it helps. Unfortunately, I can not get the exact dimensions of the ports. I'm sure there is a guru on here who can provide the specifics.