Hartley - Luth Drivers

[shaansloan]

I came across these huge old cabinets at a yard sale....when I hooked them I was impressed by the sound....great sound! When I opened them up, I found (1) full range coaxial driver called a Hartley - Luth 220MSG...

A few pics.....
Shaan

[shaansloan]

I found (1) full range coaxial driver called a Hartley - Luth 220MSG...
Shaan

Here is a post I found on AK about these drivers...

http://www.audiokarma.org/forums/image.php?u=57&dateline=1183292112 (http://www.audiokarma.org/forums/member.php?u=57)oldtubes (http://www.audiokarma.org/forums/member.php?u=57) http://audiokarma.org/forums/images/statusicon/user_offline.gif
AK Member
Join Date: Jun 2002
Posts: 333


Jack,


My Dad and Harold Luth were friends. Harold Luth designed and built the 207MSG(7" tweeter), 220MSG(10" full range), 218MSG(18" woofer), and the 224MSG(24" woofer) for Hartley. The 220 was the first and he started making them in the early 1960's. All these drivers were hand built in Holland Michigan by Harold. He had several patents for their constructions. They all had his all-polymer speaker cone with magnetic suspension. The magnetic suspension is a band of iron particles bonded to the voice coil that provide the restoring force to return the cone back to the neutral position. This makes the speaker very fast for its size. The 207 and 220 have a dual coaxial voice coil with the inner voice coil a shorted aluminum turn driving the smaller high frequency cone. Both woofers have 14 pound Alcomax magnet structure and the 207 and 220 have 6.1 pounds magnets. All speakers have cast aluminum frames. In the 80's the English Alcomax magnets were hard to get and he switch to a same strength ceramic magnet.

The following is a picture of my home built Concertmasters. They were built in 1982 and have the 224, 220 and 207 for the drivers.
Harold helped with building the crossovers. We hand wound all the inductors.
The advertised frequency for them is 16 to 22k.
My Concept 16.5 drives them.

[speakerdave]

Garbage. Set them out on the curb. I'll pick them up tonight.

Edit: As I am sure you have figured out by now, these are a unique and actually rather good-sounding speaker. Although intended as a full range, Hartley itself supplemented with a tweeter added in at about 3000 Hz and an additional ten-inch woofer in a later model system (Holton Tower) which I had for awhile. I fooled around with the 220MSG's in different combinations. The best was the 220MSG full range and four Jantzen electrostatic tweeter panels per side. Very nice at moderate volume with acoustic instruments and voice.

They are not very efficient or dynamic, and if you want to play anything at volume, you need to keep some JBL's. Hartley rather insists they be used in a sealed enclosure (infinite baffle size) and maintains that the usual T/S parameters do not apply. When you are ready to pass them on, you will be rather pleased with the response on ebay. One of the items I regretted selling, I might be coaxed into a trade for some JBL.

Good score.