Power amp for Klipschorn

[pieterv1]

Here's a closer pic. I think they were from the 60ies/early 70ies yes. Crossovers were renewed, but I forgot to take a closeup picture. I've got a few extra pictures the guy sent us before though.

The owner took his stuff pretty seriously and brought foam/rubber strips to make things airtight indeed!

 

[mhardy6647]

Easy peasy: "L" = 1973. My '74 Cornies were "M".
Double checking, I found this.

Klipsch Serial Number Lookup (beta)

Here's a handy little serial number decoder to help figure out when your Klipsch were likely made. Includes Includes full coverage for Heritage models like Klipsch Heresy, Cornwall, La Scala, and Klipschorn, as well as later models like the Chorus, Forte, and Quartet, but should work on most...

auralhifi.com

entering those parameters gives the following result

 

[garyrc]

I cannot tell from the photos -- but are those K-horns tight in the corners?
I believe that they're supposed to be ...

Yes, the older ones need to be sealed into the corner, either with neoprene sheets stapled or with foam pipe insulation (as nearly closed cell as you can get).
Then, push the Khorns into the corner until the foam is properly squished.

Even the new K-horns, with closed backs, need to be as close as possible to the two walls that make up the corner. If they need to be toed-in (or out) so that the listeners (with a flashlight) are looking down the tweeter throat, that is permissible, but not out from the corner by much. They need both
boundary (corner & floor) gain & room gain (not outside!). I doubt Stereophile's results because, to measure, they put the Khorns up on a furniture dolly and measured it outside in a driveway.

I wish I had saved a full range graph of our Khorns flat, without Audyssey or bass boost, or treble boost, but I didn't. Here is the high frequency portion of an old Khorn graph we ran, through a questionable sound card:

Hi Frequencies, without Audyssey, and treble flat.

Below is the curve I devised for those CDs, Blu-rays, DVDs, etc., which are sorely lacking in bass:

Notice this is similar to a slightly exaggerated Harman curve in the bass, without the treble roll off, matching the unsophisticated listeners curve (like my usual Home Theater audience) but really meant to put back missing bass).

Here is the infamous Stereophile curve for new Khorns, taken on a furniture dolly, in a driveway, outside -- I presume this is what is called "free air," which deprives the Khorn from utilizing the walls (and floor) to continue the horn, more or less, for boundary gain and room gain:

The bass and midrange curves are with the same drivers and horns as ours, but the tweeter is Klipsch's new one.

Here is a Klipschorn curve from a French magazine 1987 Nouvelle Revue du Son that is much more like what I expected than the Stereophile one. It was from a 1987 Khorn (they hardly changed after 1983, until the current model), in a room I presume.

 

[Ciobi69]

That's right , this speaker was disegned by extending the horn on the corner+utilizing room gain