Klf 10 improvement

This blog is translated from dutch to english to share this project with more people. Please keep this in mind when reading odd english.
hope you'll enjoy it.

In the lucky holding of the good old klipsch KLF10
speakers for a while now.
I've been searching for the KLF 20 on the web to make my music sound even better.
Then I stumbled on forums about klf's weakness The glue they used is from poor quality.
Now I know why when played out loud the source of rumbling. Al the time thinking my furniture sang along with the music.



Acording to "thirdeye's" post on the klipsch forum. Thirdeye thanx for youre post learned a lot from it.

The KLF 10 can even sound better with a little modification.
As my brother would say "My hands started itching"

It's a good thing the glue gets bad after 30 years. Let the project begin.




To separate the front was a though job. The glue was only well fixed in the corners.

Between the big speakers as you can see on the picture was a little piece of timber on which the glue totally came loose. While taking out the front panels I broke one. Hmmmppf be calm you can fix it.




Behold the stripped KLF 10

The rectangular hole is for tweety it was crammed with isolating materials you know the kind of what a mattrass is made of. That's about all the isolation the speaker had. The rumor is that Klipsch uses as less iso as possible to make it sound as loud as possible. The more space for air. This type is good fore 97 Db, if they sound better with iso I.m about to find out.

Time to glue laminate  underlayment in the cabinet. A flat 5mm thick made of pu foam should stop 22db of sound if you believe the description.

Universal floor glue did the job. At first used tile adhesive but then the foam started to dissolve.
Well that's how you learn.



Isolating horn tweeter,

Used same glue/foam with masking tape.

Finally complete sealed with acrylic kit the first horn not so carefully The second one as airtight as i could.

The philosophy is to prevent the pressure wave coming from the mid/base speaker to vibrate the horn on the tweeter to prevent dissonance.



The KLF's are put back together There's still a lot to do but wanna know if I'm at the right track.

Blimey there's a difference in sound. The precisely sealed horn sounds crispy, louder. To sort out if it's an acoustic problem i swapped the KLF's from place.
And then I heard the tweeter did nothing at all cause it wasn't connected! Now i feel a bit like a dummy. But after connecting there still was a difference so the tweeter is also sealed as good as airtight as I could. There problem solved.

Here the horn in placed in the front with 2nd iso layer sealed with kit.

1st horn also second iso layer precise sealed with kit as you can see on the image.

2nd (bether sounding) not sealed with kit just taped. aperrently this time not so important to work exact. My gues is that the soft foam is easy permeable for pressure waves.


Tweeters sound better but still a bit to harsh.
I've been told that horns always sound like that but why. It's just a membrane (as in the mid/base speakers) producing sound that travels to the horn a sort of amplifier and filter as well.
My guess is the plastic horn resonates so i glued some wood veneer in it. There go's almost all the high, way to much.


Here you see the horn slightly rubbed in with gesso primer. Already enough to get rid of the harsh sound.
Besides i like the retro look it ads.

If you see the original image of the KLF10 at the top of this site you notice that the membranes from the tweeters and mid/base speakers are not aligned, tweeters go about 4cm deeper. That means the high tones reach the ear later then the rest with results in a messy sound. Let's do something about it.

A piece of wood to get the horns out to align them.

Why didn't do Kipsch this?

Cause it looks weird ore to expensive or to much work?
I don't know but if it sounds better it go's in my KLF's

The cabinet isolated with 2 little wooden bars in it. To connect the front and back panel firmly to each other.
Been told to that the back panel gets the biggest air kicks and resonates at first. Sounds logic to me.

The bottom gets concrete ore sand thinking about that.















The result for now if it's all ok then I start making it nice.






 

Also changed the wiring from metal to copper 2.5 mm
and soldered straight on to the speakers no clips. Only 2 where the outer cable meets the crossover. Tried soldering but every time the wire came loose to hot solder iron to short wire i think.
My guess is that the soldering instead of using clips to connect. And the chance to copper did help. But next time i take slightly thinner wires. It toke so  much heat to solder them that my tweeters started melding. Be aware all the time.











This is how they look like now.















Doe they sound better?????
Yes they do, at first modulated one, then started listening to both and did hear difference.
As if the sound comes easier out of the speakers.
Must say if you like the typical sound in Klipsch speakers leave the gesso.
Now they sound a bit more to neutral
I'm satisfied with this project changes to be made in the futere will be blogged.




Questions to other hobbyists


Crossover
Has someone  got a schema from the crossover filter in the KLF10?


Other comments also welcome.

Kind regards Oldroot,