1954 K-horn weak bass?

[audiobag]

I just purchased a beautiful 1954 K-horn at a sale for $400. It looks and sounds great - although the bass sounds a bit weak and less punchy than I would expect. I am using a big vintage Pioneer ss receiver and I do have the speaker in the corner. The speakers I am comparing it to are an old (50's, early 60's?) pair of Altecs. I was about to open the access panel on the K but I noticed that it seemed to be sealed for airtightness so I backed off. Any thoughts for a newbie? thanks, Al.

[Derek]

Al,

Welcome to the board.

I would take the back off and take a look.

Check the connections and the overall construction inside. Make sure nothing is coming apart. 1954 is getting pretty old. Take a good look at the caps on the crossover (though they should not effect the low end) make sure they are not doing any leaking.

Do not think Khorns were sealed, but if they were, a gasket would not be hard to fab.

Derek

[Bill W]

Hi Al-

Considering the age of the speaker it is a good idea to inspect the woofer for damage. My first pair of K-horns were of similar vintage as yours (about 25 years old when I got them in the mid 70s.) The woofers were Stephens Trusonic - rugged and well-built however they were badly deteriorated along the surround portion of the cone with numerous cracks and tears. This condition will kill the bass performance! If your woofer is original it will likely be a Stephens 103LX2 or an Electo-Voice EV 15 WK.

There are a few more things to keep in mind:

50s era woofers were LOW COMPLIANCE- they were very stiff. The surround was generally made from the same material as the cone and was prone to deterioration from many years of use. The current production woofer K-33-E

has been used for over 25 years and easily outperforms the older units used in K-horns of the 50s and 60s.

Your Klipsch bass horn uses a removable woofer mounting board inside the back air chamber. It is secured to the throat section of the horn on each side by two angle iron brackets held in place by wingnuts on studs. The motor board that the woofer is mounted on was changed in the early 60s from a slotted opening of 6" to one of 3". This was done to improve the frequency response above 250hz. This modification makes the woofer less sensitive to losses when the speaker doesn't fit tightly into the corner.

If your goal is to preserve the speaker in its original condition, the woofer can be reconed if needed, otherwise the current driver can be purchased new from Klipsch.

When reinstalling the woofer in the back air chamber, it is very important to avoid air leaks between the motor board and the horn throat. Be sure to inspect the gasket carefully and tighten the wingnuts properly.

Please let us know what you find inside! We will try to help with any questions you may have.

Good luck,

Bill

[jdm56]

Just out of curiosity; do you intend to use that klipschorn by itself? I assume you do. Does that mean you feed it with a mono front end of classic vintage, perhaps? How about source components? And one more; do you also maintain a separate stereo rig?

I hope you don't mind the grilling. I just wondered how far somebody might take the retro thing.

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JDMcCall

[audiobag]

thanks to all for the great replies - this is a great group. To Derek and Bill - I will look inside tomorrow and post a follow-up, I hope it isn't too grim. The sound isn't breaking up or anything - when I put the "loudness" function on the amp - it sounds pretty good. Anyway, we will find out. To JD - I think you are way ahead of me on this one but I am definately into the vintage concept. I would like to use the K-horn in conjunction with my Altec "Carmels" in some way. With a vintage mono tube amp sounds like it would be a beauty. Right now I have a 4-channel Pioneer QX-9900 hooked up to 4 Altecs and I also have a Mcintosh C 26 with a MC 2105 into the Carmels. My main sources are my Teac X-2000R reel deck and my Muntz HW-150 4 track deck. With the acquisition of this K-horn I think I am going to get the fever for another one and some nice old tube amps. I've picked up all the stuff I have at various garage and estate sales - being a school teacher I can't afford to pay top retail for the choice gear. Sorry if this is too much information but I am just excited to be part of the Klipsch "club" - thanks again, Al.

[sunnysal]

I hate to keep harping on this BUT be careful when you pry the access door off! it will drop towards the floor and yank on the connections tabs of the woofer (on mine it broke the tabs right off!) you need to slowly un-stick the door anbd support it sdo that it does not hang off the woofer by the wires....then you can check out what's inside...just trying to help you avoid a "stupid error"made by yours truly....regards, tony

[audiobag]

thanks for the tip Tony - turns out that the door did have some kind of sealant/stripping and the wires to the woofer were not that short so I was able to remove the panel with no trouble. Inside is a beautiful blue Stephens woofer that looks like its new. I found no cracking or deterioration to the cone etc... at all. I tightened up the wing nuts a bit and the only thing I noticed was a build up of white calcification(?) powder on the bolts and wing nuts - otherwise everything looks great. I then started wondering about the wiring and polarity. I noticed that the way it was set up - the wire from the pos. post on the woofer (red) leads back to the right side (as seen from the rear) screw connection on the "woofer" crossover terminals. Is this correct? I was going to reverse the wires from the amp also to see if this made any difference. I guess what I need to know is which of the connections on the crossover terminals is pos. and ground. They all have red dots in front of them. - thanks to everyone, Al.

[audiobag]

I reversed polarity from the amp to K-horn and it seemed to boost the bass response quite a bit. So I guess the pos. terminal is on the right side of each pair. I'm glad I looked inside - please write with any other suggestions, Al.