La Scala resonating?

[Vetts and Horns]

Hi,

I just want to say that I'm new to this forum though I have been reading most of the threads for a couple of months now. I have to say that I do love it! Its great to see people having so much passion for audio reproduction as I do! I've recently been introduced to the world of horns (I had been listening to M.L. Arius speakers for the last 8 years or so) and I have to say I'm hooked. A friend introduced me to his Klipschorns and well I don't have to tell you all the result.

Anyway, I just recently picked a pair of La Scalas and have performed a couple of tweaks.

1. I removed the diodes from the tweeter circuit of the AA crossover. I heard a slight improvement in the definition.

2. I removed the tweeter and placed it on top of the speaker vertically. This was a major improvement in my opinion. The speakers suddenly sounded tall and open. The short boxiness effect had been reduced quite a bit (If you have heard M.L.'s and K horns then you know what I mean).

3. The last tweak I did was to was to remove the horn from the tweeter. This reduced the output a little but increased spaciousness and definition.

I now love these and can finally say goodbye to the Martin Logans. (I just sold them but he really wanted my La Scalas instead!)

Now, to my question...ocassionally, I detect what I perceive to be distortion in the form of resonance coming from the midrange horn. The song(s) that are most prevalent of this are from the Titanic soundtrack, particulaly the opening one. Whatever that instrument that is used throughout,just sounds irritating on the La Scalas to me(what is that instrument anyway?) Has anyone else ever notice this? Its not that I like this soundtrack in particular but I use it to set the subwoofer level and thats when I noticed it. Everything else I play through the La Scalas sounds good so this doesn't bother me too much. I was just wondering if anyone else ever notice this. I have tried several different amps (tube and SS) as well. Its still there. Maybe its just me!

Thanks

[WMcD]

Gee, I thought there would be a pile up of people responding.

First. One widely advised tweeks is to put moretite on the midrange horn. The exterior surface which is inside the box. I don't have LS or authentic Klipschorns, so I've never done it.

Second, some recordings are poorly done. The LS show them up. If you have this problem with only one recording on only one track, that could be the case. I'd think the Titanic soundtrack got lots of TLC from the engineering staff, but who can say for sure.

(I have a CD of Court and Spark which breaks up at one point on every system on which I've used to listen. Either it is very challenging, or someplace, the many steps of the recording system got overloaded.)

There was a review of the K-Horn by Richard Heyster in Audio, long ago. RH was an accomplished engineer, perhaps in signal processing. He reported sibalances in female vocals. He attributed it to some unknown interaction in the crossover between the mid and the tweeter. Also maybe interacting with the time delay. The LS is similar, so you might be hearing what he was hearing. But what anyone is hearing, we don't know.

The Atlas midrange driver in some models had an issue with a spike at the high end. This was solved by owners with the installation of a "P-Trap". You can search. Just two additional components in the crossover. (Usually used in the K-Horn, but obviously material to the LS.)

Let me add that if you have an AA crossover, it may indicate that the driver is the later one from EV. So this is not applicable to your situtation.

One friend of mine reported that the P-Trap improved things. He also reported that his daughter recoginized the change instantly. One lady friend of mine has made some comments on reproduced music which leads me to believe their ears may be more sensitive to the problems of spikes. Maybe you could seek a second opinion from a female, to add to your's, on the nature of the problem.

A lot of people like Al. K's crossovers. They may help you. Also, Al has replaced the K-77 with another horn tweeter. My gut feeling is that what you're hearing is not a tweeter problem. OTOH, taking the horn off the tweeter gives me a case of "the nameless dread". Smile.

Gil

[Audio Flynn]

Most times I infer there are incompatabilities in the digital source material and the speaker.

Some CDs have irritating passages or singular instruments. I hear cymbals reproduced poorly because i have a ride cymbal in the house and focus on that instrument.

The female vocal concern brought by Gil is somehing I will listen more closely to.

2 ideas from the orional recording.

1. Poor use of compressor/limiter

2. Overdriving the microphone diaphram. I used to like the WHO allot; Daltrey's vocal gets out of control(on purpose perhaps) and the diaphram cannot reproduce the spl.

A neat question that does not have an obvious root cause.

[JohnA]

Which xover and midrange driver do you have? The Type AL xover is notorious for resonances and odd noises. The others are not too bad. The K-400 aluminum horn will ring, but not that badly. You will hear it and I use the Titanic soundtrack to find those odd resonances. However, the resonances I had on "Titanic" came from the Type AL crossover, not the horn.

IMO, the best sounding crossover for the big Klipsch is a Type A made from Premium components (sparing no expense on Hovland caps, for example). The best all around crossever is the Type AA made from those same premium components. John Warren has made a *beautiful* pair for his K-horn. There are pictures on the Forum.

[artto]

Gil.Richard Heyser was one of the unfortunate aerospace engineers who got laid off from NASA when the moon race was over & the space program pulled back.

Vetts & HornsAs Gil mentioned, the mortite rope caulking has been used on the mid horn. I wrapped mine with several layers about 20 years ago. I cant tell you for sure if it actually works. Difficult to make comparisons back & forth as that stuff can be difficult to remove. But I guess it doesnt hurt to have a little insurance. However, the newer K401 horn (upgrade $50 each I believe) are made of a molded carbon fiber composite material & have ribbed rings around the outside of the horn to reinforce the horn body. So, in a way, I guess that confirms that there must have been some amount of ringing from the cast metal K400 horn.

Taking the horn off the tweeter is not a good idea. A compression driver needs the acoustic loading that a horn provides. Otherwise there is a gross acoustical impedance mismatch. Efficiency is greatly reduced. And distortion increased. Not to mention the frequency response anomalies that would also result. And contrary to what you say you observed, the horn actually INCREASES the spaciousness because it spreads the sound with controlled directivity, directing the sound dispersion across a specific angle (vertical & horizontal) of radiation required for the recommended listening area.

Removing the tweeter diode protection from the crossover is good for better sound. Ive done the same thing. You might also want to remove the inductor from the bass driver. It smooths the 180Hz bass hump a few Db.

Not sure about placing the tweeter vertically. The speakers are perfectly capable of sounding tall & open without vertical mounting. Klipsch vertically mounted the tweeter for a short time many decades ago. Possibly what you are hearing is the effect of not having that ½ one-half inch opening in the plywood mounting panel interfere with refraction. That has always bothered me on both the midrange & tweeter horns. Ive always wanted to change that but I also dont want to destroy an original vintage product like the Klipschorn. IMO the mid & high horns should be flush with the front surface of the panel to reduce very short time delay refractions off the edges of the plywood opening.

As far as the horn distortion youre describing, again Id have to agree with Gil. I think youve just discovered the extremely revealing qualities of well designed horns. My answer to all those horn problems was to build an acoustically tuned room for them with appropriate amounts of both diffusion & absorption. Youll never hear what those speakers are capable of until you hear them in that kind of environment.