new to me 1972 speaker lab k horn

[HIFI4EVER]

Original builder just downsizing in his 80's.  He had these half of his life..  Over all good shape.

 

They have the fiberglass horn.  They are sensitive compared to my 901's, that I power with 2 qsc 600watt RMS amps.

 

He thought a mouse got in them, so I figured the woofer might be toast.  I gave them half power of those amps and they took it and shook the house like mad.  I was surprised considering he said they have some U shaped magnet on the woofers I thought they would be junk.  They took WAY more juice than most speakers can and were fine.  I thought these are only rated 100 watts max.  They won't be played that way all the time of course, but the drivers seem fine.  I don't care for the tweeters much.

 

 

QUESTIONS:

-They do have leaks after running 300 RMS watts through them I found.  Should I just RTV them?

 

-There is no access hole for the woofer, how do I change it?

 

-Is it a sub  (should be) ?  Meaning can I put a more sub like woofer in there?

 

- can I buy new grills and grill frames?

 

-I think I'd like them sealed, or what about a free air sub in them?

 

photos from for sale ad.

 

 

 

[Marvel]

 

Welcome to the forums. The Speakerlab K is, for all intents and purposes a knockoff of the Klipschorn. The 15 inch woofer is in a folded horn, with the bass frequencies coming out each side of the back. When installed correctly, the corner then becomes the last bit of horn length. All joints in the cabinet should be checked for leaks, and yes, rtv would work for that.

 

Since it is horn loaded, only certain woofers will work. These are super efficient, and can be powered by amps ranging from 3.5watts and up. Bob Crites: http://critesspeakers.com/

has most of what you might need for these. They aren't Klipsch, but they are still good speakers. Since they could be built from plans, the build quality could be trash to superb.

 

Bruce

[HIFI4EVER]

Thanks for the reply.  So if I was to replace the sub, can I go with one of lower frequency ranges?  Does it have to be less rigid?

 

BTW  I know people don't like BOSE and that's another ball game, but my series1 eq with these things is night and day difference in several ways.  I tried it and found it to bring them to life.

 

I just tried moving them around and forget about the eq comment.

 

BUT I need these sealed or something, the bass is not keeping up with the mids and highs

 

 

 

 

[WMcD]

Welcome from me too.

 

I agree with Marvel with some added comments.

 

There should be a hatch in the side of the bass horn.  That is where you gain access.

 

Speakerlab sold a full veneer kit and maybe that is what you have.

 

Any grill frame, etc. could only be obtained from Speakerlab and I'm pretty sure they are no longer supporting the SK.  But you could try contacting them.  I suspect they are held in place with Velcro type hook and loop material.  I'd try putting a butter knife or putty knife at the edge and pry them off.  Grill fabric is available widely.  Crites has some.

 

Sometime in the past I posted info on the T-S parameters of the two woofers from SK.  My conclusion is that they are not even close to the K-33 used by PWK.  I think Klipsch will not sell you a K-33 unless you provide serial numbers from a Klipsch unit.  People have used all sorts of substitutes. 

 

I suspect there is a critical function to form a chamber in front of the woofer diaphragm to peak up response in the 200 to 400 Hz range.  The volume (like cubic inches) has to work with the mass of the diaphragm.  The K-33 has a very thick gasket.  It will prevent bottoming out of the diaphragm.  But I suspect it is there too, to form a somewhat larger volume.  If so, a substitute woofer may or may yield optimized performance even if better than the SL units.

 

The is a Dope from Hope where PWK reviewed an un-named copy but it must have been the SK.  There is a gap above 200 Hz.   He also sued or threatened suit over the use of the K in SK.  Then SL switched to a back loaded bass horn for a while. 

 

SL sold a plastic tweeter which was cheaper than the Electrovoice units which they offered.  Bob will sell  you his replacement for the tweeter if you're interested. 

 

The crossovers came in one variation with switches and another with L-pads, and maybe others.  I can't say how well these will work with new tweeters and woofers. 

 

RTV what you can. In some SK's the wedges at the top and bottom had a notch to communicate the volume inside to the back chamber and thus is a potential source of a leak.  You'll have to RTV from the outside. 

 

The SK was a good project in that it allowed many people to assemble the kit with great enjoyment.  Even before then, there was a TV commercial for a headache remedy.  A young woman was cooking something and her mom was giving unwelcomed advice.  The young woman held her head from a headache and countered bitterly, "Mother, I'd rather do it myself." 

 

Tinkerers are like that.  Smile.

 

WMcD

 

 

[HIFI4EVER]

Awesome input, thanks.  I think they can take lots of power with out distorting, but I don't want to blow out my ears or deal with cops so I think I'll try the cabinet sealing first.

 

So, if you think the firmer woofer would work better that is what I thought.  I mean I have used car subs like JBL  in some builds that worked better than anything else.

 

I thought about trying to match the specs like the eminence 15 or whatever, but if a newer beast of a sub will work I don't care what is in it so long as it gets long and can take what I give it.

 

Cabinets have no access panels.  He said he ordered a kit, but tis is 3/4" wood too I think that is thicker, plus the no access thing....

 

 

One more MAJOR thing, he put rollers on them so they sit off the floor a little, they seem to be a on a riser as well compared to other photos does that affect bass and reduce bass?

 

53" H, 33" W, 25" D

[Marvel]

They aren't subs, they are woofers, on the Klipsch model, specified by Klipsch and made by Eminence.

 

Bruce

[HIFI4EVER]

Okay, so then that would mean they are used for certain frequencies or does it mean they used what they had available back then?  I would assume that a sub would be better in a bass bin, and a woofer is better when you need certain frequencies from it.  Maybe I am confused here what the intent was with these speakers.

[ricktate]

Well never seen a speaker lab speaker. But you can do some research on them and there has to be an access panel somewhere on it. Put some pics on here of the inside of the top part which should be open. Pics of both sides also.

  The woofer that goes in bass part of the cabinet has to have certain parameters and a woofer for a SUB is not going to work right. As far as the leaks go can you see where they are?  My 1974 Klipschorn had a few leaks and I repaired them from the inside with regular wood glue.  The crossover probably needs to be recapped also.

  There are 2 drivers in the top section not sure if crossover points were same as Klipsch but probably close .

[ricktate]

[ricktate]

[ricktate]

[ricktate]

[absolve2525]

How are the Speakerlab woofers "not even close" to the K33? They had 4 and 8 ohm versions, I believe. 

[HIFI4EVER]

I looked at them before buying and asked him, he just built the sides with no panel.  The rest all looks the same, but maybe thicker wood.

 

I'm not able to rely on corners so these will need some more wood added.

 

I'd honestly like to see and hear more K horns but nobody uploads vids of these for some reason. (there's a couple"  If I have the "crap" woofer I'd probably be real impressed with others.

 

 

[avguytx]

You can't really "hear" Khorns in an uploaded video on youtube. I've never understood why people post videos of their speakers playing in a room recorded on a Web cam microphone to be played back on laptop speakers or a phone. But that's just me. Good for "seeing" them set up but that's about it. 

[DizRotus]

The Speakerlab woofers came in 4 ohm or 8 ohm.  They were good woofers.  I purchased 4 factory-built Speakerlab Ks (8 ohm) ~1976.  If necessary, the Speakerlab woofers could be replaced by woofers from Bob Crites.

 

My concerns would be the following:

• factory-built or kit built  by owner;
• still sealed joints, whether kit or factory; and
• crossover networks.

I don't know how you can confirm the integrity of the many joints inside the bass bins, whether a Speakerlab or Klipschorn.  I routinely seal joints in decades old La Scalas, Cornwalls, etc, which are accessible.  The many joints in a folded horn bass bin are not accessible  Good luck.

 

 

 

[Marvel]

"I looked at them before buying and asked him, he just built the sides with no panel.  The rest all looks the same, but maybe thicker wood. "

 

That's pretty crazy. I guess you could plan on replacing the woofers and use a router to cut the access. Then vacuum out all the chips and dust. Seal what you can get to and put new woofers in, adding the access door.

 

 

[HIFI4EVER]

1 hour ago, DizRotus said:

The Speakerlab woofers came in 4 ohm or 8 ohm.  They were good woofers.  I purchased 4 factory-built Speakerlab Ks (8 ohm) ~1976.  If necessary, the Speakerlab woofers could be replaced by woofers from Bob Crites.

 

My concerns would be the following:

• factory-built or kit built  by owner;
• still sealed joints, whether kit or factory; and
• crossover networks.

I don't know how you can confirm the integrity of the many joints inside the bass bins, whether a Speakerlab or Klipschorn.  I routinely seal joints in decades old La Scalas, Cornwalls, etc, which are accessible.  The many joints in a folded horn bass bin are not accessible  Good luck.

 

The guy built them.  When I say they leak I found one spot that is blowing at very loud volume, maybe more than they should be pushed.  I just gave them some bass and they can take it even at higher power with out distorting so I think I am fine with the woofers.  I'll go around and fill in where there is no sealant and then worry about putting the panel extensions on the rear.  I know they make bass, but I hope that adding some side boards will help finish the cabinet and direct the sound up front.

The crossovers only have one control for the tweeter and nothing for the mid.  I/m not sure I like crossovers, but for now they work, and as usual with big speakers they sound better the further I am away from them.  This pic is basically the parts mine have.

 

Quote

 

 

[DizRotus]

2 hours ago, HIFI4EVER said:

 

I looked at them before buying and asked him, he just built the sides with no panel.

 

 

My factory-built units had access panels.  I believe the plans described access panels.  Please note in the photo the lighter rectangular area surrounding the triangular hole.  The cover to that access hole is a large rectangle, not a triangle.

 

 If, indeed, yours were built without access panels, I would do as Marvel suggested above.  I would cut an opening and fashion a rectangular panel to cover the triangular access hole.  I would put the unit on saw horses with the area to be opened facing down to minimize sawdust from getting into the woofer.  Rather than attacking the unit with a sabre saw, I would drill many small holes upward in the shape shown in the photo.  Be careful to drill to the insides of the motorboard and rear chamber walls.  If the tiny drill bit does not strike air ~0.75" in, stop and drill closer to the center of the eventual opening.  After successfully drilling MANY small holes in the shape of a triangle, I would then use a keyhole saw to "connect the dots" and remove the panel.  After removing the woofer and vacuuming out any sawdust from the woofer, I would use a router or sabre saw to clean up the opening.  After vacuuming the chamber, I would reach into the chamber to seal all visible/accessible joints/seams with RTV.

 

Or, hook 'em up as is and let the music fly.

 

[HIFI4EVER]

Oh, so you guys are saying they can leak inside as well and loose performance?

 

Also; who has done this mod before?