Johny Holiday - describe your Karlson's X15 sound, positive attributes and weaknesses

[freddyi]

hey Johny - - I've not seen any other Karlson X15 owners online. As we know, X15 were ~28" high, 20" wide, 14" deep and first mention (to my limited knowledge) appeared in AUDIO directory of October 1965 and implied the waveguide driver at that time to be a 3" cone. David A. Young said that waveguide was a wooden structure. Later X15 had compression driver and slotted metal tube - mine were 1.875" inside diameter, ~7.25" long from tip back to the treaded phenolic plate and had 1.5" long internal pre-waveguide having a 30 degree slice. IIRC your X15 may (?) have had a 1.25" diameter waveguide tube and dispensed with that internal piece (?)

my X15 came with CTS 54oz magnet woofer with paper surround, IIRC the TS parameters were Qts ~0.28, fs-41Hz and Vas around 10 cubic feet - there appeared to be no lowpass crossover filter - was yours like that? Mine were missing the high frequency driver and the tubes were replicated,

my sample of X15 had no rear lowpass shelf - -yours and the Ebay organ models had that feature. The Ebay organ model had a large rectangular port and none of the distributed de-Q-ing holes seen on our X15.

my impressions of the waveguide was that it sounded very "fast" with good amount of energy launched about everywhere in the room including perpendicular to the tube's long wall. I thought in ways it sounded like a JBL plate lens but had none for direct comparison. The paper surround CTS is nice and reasonably articulate - I'm guessing its 3.1mH of voice coil inductance "was" the crossover (?)

if you have any recent pictures to share for this and Gregg Baker's Karlson Loudspeaker forum, it would be well appreciated. (at least by me - lol)

only one pair of X15 came up for auction/sale in the last two years but those appeared to be built for organ use having a rectangular horn placed in front of the woofer and angled up quite a bit on brackets.

I sometimes like the 12" cabinet too, its better on Gary Karr than my Klipschorns (whose bass is muddied by bad walls)

Freddy

[freddyi]

I've forgotten what Johny Holiday said for the width of his X15 - mine is ~19.25" From pictures saved from Ulfman's old forum, Johny Holiday's X15's waveguide tube appears to be 1.25" or so in diameter and dispenses with the "pre-waveguide" seen in my X15. Also his X15 has a rear lowpass shelf. John Karlson apparently experimented with certain features in his factory loaded systems. I have a few more pics of Johny Holiday's X15 - one of it as center channel - other with woofer coated with expanding damping foam.

a couple of years ago, a pair of X15 appeared on auction featuring a horn in front of their woofer and a single port instead of

de-Q-ing holes in an array, and its original Kimsul damping material was intact - probably due to grill cloth preventing

entry of mice.

a rear view of one of mine before the seller crudely removed with saw the waveguides and compression drivers

which were sold to another Karlson-nut

the CTS woofer in mine measured as follows:

X15 CTS T-S

Revc = 7.1648 ohms
Fs = 41.8850 Hz
Zmax = 153.1167 ohms
Qes = 0.2856
Qms = 5.8182
Qts = 0.2723
Le = 3.1031 mH (at 1 kHz)
Diam = 323.2150 mm ( 12.7250 in )
ConeArea =82048.9302 mm^2(127.1761 in^2)
Vas = 265.6837 L ( 9.3825 ft^3)
BL = 18.4180 N/A
Mms = 51.3835 g
Cms = 280.9952 uM/N
Kms = 3558.7798 N/M
Rms = 2.3242 R mechanical
Efficiency = 6.5893 %
Sensitivity= 100.1884 dB @1W/1m
Sensitivity= 100.6672 dB @2.83Vrms/1m

[Ocnorb]

I think I still have plans from waaaay long ago about how to make some Carlson Ultimate Speaker Enclosures.

They looked very similar to the pics but used a 3-way JBL 15" speaker and were somewhat larger than these pics.

A friend of mine made a set but used 12" speakers instead.... never did get a listen on them []

Jim

[freddyi]

It would be fun to see a scan of your Karlson plans - there's a chance its something not seen for a long time.

Karlson's little X15 at ~4.2 cubic foot external bulk was just a bit larger than the 12" enclosure so its half-space low frequency

corner like the 12K was around 80Hz.. (A Peavey FH1 which was like a 6" deeper Belle had a half space low frequency corner of around 110Hz/12dB per octave.)

last year I uploaded Julian Hirsch's "The Audio League" report of October 1955 where the Karlson 15 and 12 were examined objectively and subjectively

http://www.audioasylum.com/forums/hug/messages/14/144523.html

[khorn51]

I have some Karlsons that are about the size of a corwall but deeper.

They came with Ev trxb12 but the cabinet sound board is cut for 15 with a 12" adapter palte.

They are not bad speakers with the Ev's and the go way lower than lascalas.

[freddyi]

I mounted a MISCO built Wild Burro Audio "BetsyK" 8" fullrange into the first Karlson Twelve (made debut October 1954) and it played very good

bass at high levels for this size driver with no more than ~1/16" cone movement in each direction - in ways the bass was better than the larger speaker behind it and certainly fun - its interesting to hear that much sound for so little cone movement. There's only about 1.4 cubic foot rear chamber so some 8" will go lower than 12" in K12. The first K12 offered a movable tuning strip - a plywood bar on the rear panel to addjust the rear lowpass gap - it does mild juggling of the first two impedance peaks.