Altec multicells (803, 805) with LaScala vs K400

[Phenton]

Seems that some have changed their horn and horn driver combo for these. Some have even gone to old Altec Multicells. Anyone here use a K55m (or V) on the Altec 803 or 805 for the midrange 350Hz up to ~ 5Khz? Anyone try a GPA390 with the above horns? Do the above multicells have directional issues (polar plot fingers) in the bandpass ? I would like to read some feedback on those combo's. Perhaps a description of the difference (pros/cons) with the Multicells vs K400 or other mid horns. They seem to have a following, but I have never heard them. Phenton

[Al Klappenberger]

Phenton,

Since this is you 2nd post, I'll say welcome to the forum!

The bottom line on the K400 upgrades is to DO IT! ANYTHING is better than the K400! Upgrading the K55 is secondary. It's not a bad driver and there is no currently made 1-inch format driver that will handle the Khorn 400 Hz crossover. To upgrade it will require moving to a 2-inch horn. Now you are talking a lot of money! Even the big 1-inch Altec drivers can be blown out by extreme lows that easily get through the 1st order woofer filters in networks like the A, and AA. They will generate a lot of distortion down low too.

Al K.

[sootshe]

Phenton,

I agree with Al.........don't bother with the K400...............I was going to go the way you are suggesting.............805 multi's with GPA 399's using the standard 400/6K crossover points, but when I upgraded to the K55 dual phase plug driver mated to an ALK Trachorn through a Sonicap ALK Universal, I was wondering what all the fuss was about.......................I've heard plenty of 2 inch JBL mid drivers mated to appropriate horns & my combo is not lacking at all.....particularly when used with a JBL 2404 tweeter...................Must confess I've never heard the GPA 399/390 with a multi................that will be my next upgrade in a year or so as I'm sure it will be the real deal..........Cheers,

John

[Al Klappenberger]

Actually, The big Altec cellular horns are intended for outdoor PA use. They are really not a good choice for a home stereo. It would still be better then the k400. The Altec 511b VOT horn is a good choice. It's actually a bi-radial exponential horn. It just looks like a cellular. Personally, I suggest one of Dave Harris's FasTrac horns.

Here's a 511b grafted into my Belle. I later went to the smaller 811b, then to a Bruce Edgar type tractrax like the Fastrac horns.

Al K.

[Chris A]

Seems that some have changed their horn and horn driver combo for these. Some have even gone to old Altec Multicells. Anyone here use a K55m (or V) on the Altec 803 or 805 for the midrange 350Hz up to ~ 5Khz? Anyone try a GPA390 with the above horns? Do the above multicells have directional issues (polar plot fingers) in the bandpass ? I would like to read some feedback on those combo's. Perhaps a description of the difference (pros/cons) with the Multicells vs K400 or other mid horns. They seem to have a following, but I have never heard them. Phenton

If you look at page 25 of the linked presentation, you will see diffraction and some reflections in a Altec Lansing 808 multicellular horn with a JBL driver.

There are three multicellular horns tested in this report--and all three seem to have diffraction issues (as one might expect from visual inspection of the horn design). Unfortunately, off-axis measurements were not made in these tests for any of these horn/driver combinations and that is a pretty important performance parameter IMHO. The Le Cléac’h profile horns apparently have larger issues with coverage than with the other horn profile types tested.

The conical design from Bill Woods (AH-300) was also in that mix. I believe that it actually did extremely well once you subtract out the driver issues for this test.

I'd also look at the K-510 horn/K-69 driver combination from Klipsch if you are thinking about an upgrade. That would take you into the "Jubscala" domain. I believe that the K-510 is a modfied conical/tractrix design done by Roy Delgado, and is a really small but very high performance design.

The tractrix design that Al mentions here will also do very well.

Chris