Bacek

For a start I would check if your amp is not "producing" DC offset. With some amount it can heat and then destroy woofer coils. Mid's and tweeters are protected by capacitors. Woofers are not.

From what I remember PWK did not liked that speaker. Wouldn't be better to build central speaker with same set of drivers you have in KHorns? You could build Corn(wall/scala) for better consistency with rest of your system.

Drivers are placed vertically so if you change your position horizontally it will not affect phase on common parts. OK you can listen standing on a chair and this way probably you will have phase "conflicts" but I guess you will be hit by horn dispersion first, or 30 cm from a speaker, which is pointless too. This is for direct signals. Of course you can be affected by reflected signals but there is no sens in considering this because same thing can happen for only single/full range driver (that reflection will react with direct signal with different phasing). Not sure where we are heading with this discussion? My point is that aligning drivers (back and front) by moving them physically or "electrically" by delay is definitely measurable and affects response on xo points as long as your drivers are more then half wave length distance.

Actually it does. FIR is not changing electrical driver phase on crossover point so there is no cancellations, only additions if you choose proper xo point. Additionally you can linearize driver phase with linearization filter and this way you are free to choose any freq for xo point.

Vertical is 5 dBa, smoothing 12 dBa. Mic is 1m of LS front. Random room placement (not optimal I would say for measurement). Because of different phase for squaker and twitter, response is hit. Changing phase of one did not helped, dips where deeper or shallower. Of course it's also result of some early reflection, but also reflection has different phasing from other driver but also form it's own. Any way adding delay for twitter helped for both. Mic was not moved a bit and nothing in the room has changed between measurements.

This is measurement of an active XO with and without time alignment. Blue is measurement of a configuration without any alignment. For green I only have added delay for tweeter (more or less distance between squeaker and tweeter drivers) and this only configuration difference between those two measurements. No a single eq parameter was changed between measurements except of time delay for the tweeter. I'm planing to measure exact impulse responses for each driver and set delays based on that measurement.

Lately I'm experimenting with active crossover (Najda DSP) and my own super elliptical tractrix horn for HF, so I'm not sure I made everything right for not aligned setup. Any way this is my measured difference for same xo setup with and without alignment. It's LaScala with K55M and B&C DE120. XO is FIR -48dBa LR@5200 for both ends. Green is (more or less) time aligned

Maybe it will be usable for someone Voster Typeface looks like one used on crossover plaques. https://fontlot.com/10242/heritage-typeface/

Anyone knows what crossovers where used in lascala with k-55-m squaker? AL to al-3 or only some of them?

Actualy all pot zones on amp should be unnoticeable noise free. On La Scala in my setup I hear any noise from "digital" rig only when I open pot completely and I'm close to the speaker, vinyl is other cup but this is it's nature. For most amps pot is not increasing strength/level of the input signal. It actually attenuates it. So what is the point of making analog signal level high on phono preamp and then attenuate it on pre/power amplifier. This is a way where noise and distortion is introduced. So I don't have any doubts on turning pot more for analog listening. On the other side if by turning pot up you hear more noises then they are just present on amp input. They could be phono preamp introduced, but mostly it's record itself. For some extend it could be cartridge but we cannot avoid vinyl noises. Newer vinyl records sometimes are "louder" then oldies but usually some other aspects of natural sound are lost on this kind of mastering.

Hi Dave A This is still Tractrix or something else? Some time ago for fun I modeled in CAD a tractrix horn with superellipsis shape at a mouth (kind of rectangle or square with round corners, depends on parameters). At throat its of course a circle (which is actually also superelipse). During the path as superelipse parameters are changing it goes from circle to almost rectangle. It was fun to go from math to cad model. Any way, while I was calculating it exactly for original LaScala cut out I was only able to produce model with horn length about 1 inch. I was little confused with one from top of this thread as it's 1,5 inch plus metal spacer between horn and driver. Then I realized that it's for z bracket version. But on last picture I also see smaller one in the middle. So any way, all of them are tractrix flares, right?

I would not trade any part of Cornwall (K55/K77 based) for any part of Forte. Had Forte I, heard Forte III. Old Cornwalls are one of best speakers I have ever heard (in any price range). Of course they are no perfect but I realy like them.

Unfortunately resistance check is not enough. But of course better than nothing. When I bought Lascalas one of the woofer was not blown but incorrectly rewired/repaired. Resistance of bot was quite similar. But impedance me sure mentioned where way off and inductance was really crazy for one of the woofers. As result they had similar efficiency above 200hz but below there was about 6dB difference. Ended replacing them with Eminence Kappa 15c and k33 waits for professional fix.

I think Claude that you are claiming reality. I heard Quater pie. They delinitly go lower than Lascalas and sound really good. But they much larger than Lascalas. Not everyone keeps Lascalas in corners and even if does not everyone has free space around those corner. Lascalas perfectly feet my room but there is no way I could squeze there Quaterpie's. Maybe single one but not pair. So Quaterpie is not Lascalas replacement for every one.

I just noticed that there is a thread with Klipsch woofers T/S data by mustang guy . Klipsch Heritage woofer T/S spec