Frequency balance adjustment by remounting the La Scala tweeter?

[Boomzilla]

I replaced the crossovers in my mid-80s La Scalas with a pair of Mr. Crites' type AL crossovers. Mr. Crites crossover slightly elevates the level of the squawker horn (if I understand him correctly). In my room, this has had the unfortunate effect of causing the treble to sound recessed. Rather than monkey with the crossovers or add L-pads, I was wondering if remounting the K-77 tweeter to the front face of the mounting-board would have the effect of causing slightly more apparent treble?

Has anyone else tried this? Of course, I'd have to cut the mounting-board so that the magnet assembly would fit through the mounting-board, but this won't be a problem for me since my speakers use full grilles and the surgery won't be visible.

Thanks - Boomzilla

[Guest " "]

I just did this to a pair of 92's. recent model LaScala's are all flush mount. I think the main expectation is less reflections...not really enough to change the level.

[Axz Hout]

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[HDBRbuilder]

Just a wild guess here, but, I would imagine that the flush mounting of the tweeters at the factory on LaScalas had more to do with commmonality of parts after they started using a different cabinet assembly method for the Heresy speakers, which required mounting the components from the outside instead of the inside. This change required the tweeter flange mounting holes to be countersunk from its face side for the types of wood screws being used to secure the drivers and horns to the motorboards of the new Heresy cabinet design in the new final assembly process. The K77M was the original tweeter used in the new Heresy cabinet design. Besides, mounting the LaScala Tweeter and mid horn from the inside was always a hassle, and aligning them to the motorboard routed openings by feel was very time-consuming

Eliminating blind installation, negating need for alignment of the horn mouth to the routed opening, speeding up the assembly, and commonality of parts probably affected the change much moreso than moving a tweeter flange forward by 3/4" to make an audible change of some sort, which the company had not seen any need to do in the previous twenty or so years of LaScala production, but I COULD BE WRONG. []

There were other perceived benefits to installing the drivers and horns from the front on the new MDF Heresy motorboard...in the new Heresy cabinet build...since the speakers could now be shipped face up in the boxes..with no worry for things loosening up screw-wise after a rough road trip to a dealer.

-Andy

P.S. Keep in mind that "perfection" and "production" have NOTHING to do with each other. Otherwise, the LaScala would have been produced with the reinforcing "wings" in the bass bins instead of without them...from the mid 1970's until the unveiling of the LaScala II model. It is fine and dandy for some sort of real or perceived CONSUMER benefit to come out of a production change, but it is seldom the deciding factor. If you have a product that gets a production change which will save the company on production costs, but whose savings will NOT be passed on to the consumers, then it is always wise to give some other reason for the change, be it real or percieved. Again, I COULD BE WRONG![]

[Boomzilla]

Uncle Paul believed that the mounting of the drivers behind the "motor board" had no effect on frequency response. I'm sure he's right. Nevertheless, the K-77 has never been known for its performance (conspicuous only in its absence) above 15KHz. I've acquired a pair of piezo electric tweeters with response out to bat-ear frequencies. I plan to just set them on top of the La Scala cabinets, hook them in parallel with the speakers, and just listen.

[Chris A]

I've acquired a pair of piezo electric tweeters with response out to bat-ear frequencies. I plan to just set them on top of the La Scala cabinets, hook them in parallel with the speakers, and just listen.

I'd make sure that you line them up at the back of the cabinet, so that they are aligned with the K-55 driver mounting face to the horn below it: the soundstage should "explode" when you get them within 1/4" of time alignment.

You could also use an EQ unit to tilt and/or boost/cut the tweeter response a bit, which is much easier to control than messing with the passive crossover networks.

Chris

[Daddy Dee]

Boomzilla,

Not sure what's in the AL crossover, but in my type A's I've changed the squawker tap on the autoformer and it drops the squawker output by 3db. Sounded very nice in one particular room.

Another option, you might enjoy the CT-125 tweeter, which is a drop in replacement for the K-77. I've used these in Khorns and LaScalas and never looked back. To my ears, there is a huge improvement in the realism of the sound.

[LarryC]

In my mind it sounds better with squawker and tweeter front mounted. Not change in level noticeable.

That's be my guess -- see if it sounds better. I thought part of the shift to flush-mounting was to reduce multiple reflections around the K-77 horn mouth and mounting board. That seems to be why Klipsch changed my tweeter mounts to flush when I sent them the tops in the mid-1980s. I thought it was a sonic improvement.<p>

So, I wouldn't be surprised if flush mounting makes them sound better, or at least I think it would to my ears. I'd be surprised if FR measurements change, but I can imagine them being easier to measure with fewer multiple reflections. JMHO.

[HDBRbuilder]

]I'd make sure that you line them up at the back of the cabinet, so that they are aligned with the K-55 driver mounting face to the horn below it: the soundstage should "explode" when you get them within 1/4" of time alignment.

You could also use an EQ unit to tilt and/or boost/cut the tweeter response a bit, which is much easier to control than messing with the passive crossover networks.

Chris

Once you get the tweeter driver aligned with the K-55 driver mounting face and get that initial "explosion" of the soundstage...you can back that section up about a foot and a half behind the rear of the LaScala cabinet so that it aligns with the location the K33 woofer WOULD BE if the bass horn was UNFOLDED...and you can have a soundstage that REALLY explodes like a 10 KT nuke once you get them ALL within that 1/4" of alignment perfection...just sayin'...[]

[Boomzilla]

Yes, an equalizer may be a more elegant solution, but my experience is that an equalizer (or even tone controls) may fix the frequency issue but often wreak havoc with the sound stage. My experience over the years is that "less tone control is better tone control."

The piezo tweeters are easy to "time align" by adjusting the spacing. Because my La Scalas have full-face grills that are approximately 0.75 inches away from the face of the motor board, I can easily mount the piezo a quarter, or even a half an inch in front of the motor board to achieve alignment with the voice coil of the T-77. Having done so, no further frequency alteration may be required. Of course, I'll have to listen to see...

Further, if I don't like the effect, the piezos are easy to remove. Of course, I'll listen to the setup before cutting holes in my motor board just to see what I get.

Since I already use my La Scalas with a serious subwoofer, the top extension will balance the bottom extension and the La Scalas will become the "squawker" between the sub and the piezos.

I'll post what I heard once the trial is made. Thanks for all the feedback - Boomzilla

[Chris A]

]I'd make sure that you line them up at the back of the cabinet, so that they are aligned with the K-55 driver mounting face to the horn below it: the soundstage should "explode" when you get them within 1/4" of time alignment.

See http://forums.klipsch.com/forums/p/148391/1531862.aspx#1531862 and http://forums.klipsch.com/forums/p/22533/183913.aspx#183913

Not that you have to listen to my opinion only. The big deal here is the audibility of the time misalignment of the LS tweeter to its midrange, which is much more sensitive to physical distance than the midrange-bass bin time alignment (10x better in fact, due wavelengths at crossover). I've found the +/- 14 inch is about the tolerance band due to the ~5Khz crossover frequency in the LS, a bit narrower than the 3.5KHz that Dennis K.mentioned in the UltraPhase crossovers.

Chris

[Boomzilla]

If I'm to align the tweeters with the midrange horn, though, I'll need to move BOTH the K-77 and the piezo. How do I do that and keep the works inside the cabinet? Doesn't seem possible...

[Axz Hout]

y

[Chris A]

I'll need to move BOTH the K-77 and the piezo.

This is only true if you were going to use two different types of tweeters at the same time on the same loudspeaker. If you are, then disregard the two entires that I've made above.

That's what you intend to do? Good luck.

Chris

[Chris A]

As far the two millisecond delay between woofer and mid-range, or mid-range to tweeter - it does exist, the Audio Engineer that produced our heritage horn speakers thought it to be inaudible. Not saying that some individuals will be able to hear it - could be a long thread indeed!

The Klipsch engineer that co-produced the Jubilee says that it is very audible. In fact, he says that the time misalignment on the midrange-bass bin is also audible. I can hear it, too, when it isn't corrected vs. corrected.

I can easily demonstrate the effect of a 2 millisecond time misalignment using my tri-amped center Belle if you happen to be in the area anytime soon. It is the difference in being able to integrate the Belle between the front speakers and not being able to.

Chris

[Marvel]

I'll need to move BOTH the K-77 and the piezo.

This is only true if you were going to use two different types of tweeters at the same time on the same loudspeaker. If you are, then disregard the two entires that I've made above.

Really? That's what you intend to do? Good luck.

Chris

If I am reading this correctly, you should 'monkey' with the crossovers. If the high freq. seem to be recessed, I would adjust the crossover to drop the mids down a couple of db. I did this on my LS, and it made the balance from top to bottom seem a lot more even. The problem (for my ears) was the midrange was too hot. Pulling it down some effectively broght the others up.

Bruce

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