Utah 18" driversw/ alnico magnets

Anyone have any info on Utah 18" drivers? I think they were manufactured in the mid seventies and had Alnico magnets. I think they were also used in Trusonic speakers from the mid 70's. I found a pair of custom project speakers that have the Utah 18' drivers with a 4" mid range and a high frq. horn. Would theses speaker be worth looking into?
Utah used to oem relatively inexpensive raw drivers for trusonic (among others). Commendably they insisted on using alnico for the magnets (an excellent thing to do, and nowadays very expensive). They also offered speakers I think...
The answer to your question is, it depends on price, the CONDITION of the drivers, and yr needs.
If the woofs especially are in good condition (check surrounds, noises, etc), you have use for these drivers, and are interested in tinkering with the speakers, then go for them. After that it's a matter of price.
18" alnico are expensive nowadays, if that's anything to go by... and some trusonics (possibly manufactured by Utah) fetch quite good prices on e-bay.
Gregm...You say "Commendably they insisted on using alnico for the magnets". I don't understand the "Commendably", because as I remember the 50's all decent drivers used Alnico. Why is it such a big deal today. I believe that various other magnetic materials are stronger.

I hope that someone is not goint to tell us that Alnico Gauss are different from ceramic Gauss (like tube watts and ss watts).

Utah was big in the PA system business.
Eldartford: "Why is (alnico) such a big deal today" Mostly because it's expensive now and not very commonly found in drivers.
Gregm...Dirty little audiophile secret!! If it costs a lot it must be good.
Alnico has at least two desirable properties:

First, alnico is less subject to flux modulation under dynamic conditions than are ceramic magnets, and this has been shown to be audibly significant (as described by Dr. Earl Geddes in "Transducers"). So all else being equal, an alnico magnet woofer will be more linear than a ceramic one within its safe operating range.

Second, alnico is electrically conductive, which effectively lowers the voice coil inductance via shorting (voice coil inductance is a primary limiting factor of a woofer's high frequency extension).

One drawback of alnico is that if the magnet is overheated, it will permanently lose flux (and have to be re-magnetized to restore performance). If a ceramic magnet is overheated, it will lose flux temporarily - that is, the flux will return once the magnet cools down. This was not an issue back in the 50's when amplifier wattages were low, but can be a factor today.

A ceramic magnet woofer with a well-designed, well-cooled magnet structure and a Faraday ring (copper or aluminum shorting ring) is competitive with an alnico unit, and doesn't have the susceptibility to permanent demagnetization if overdriven that the alnico has. The manufacturing cost of such a woofer is usually less than an alnico one, but is still high.

As an example, Pioneer makes some excellent alnico magnet prosound woofers, typically rated at 300 watts. This is more than enough power for home or studio monitor use, but probably not enough for dance club or sound reinforcement applications. A number of manufacturers make ceramic magnet prosound woofers that can handle 2000 watts or more.

Alnico magnet drivers are often described has sounding more lively and/or more harmonically rich than ceramic magnet drivers, but unless the comparision is with a very high quality ceramic unit I'm not sure it's a fair comparison. I don't have a hard and fast opinion on which is best for home applications; I've heard excellent speakers that use both types of magnets.

I think that the high quality woofer magnet material of the future may well be neodymium, which from what I understand has many of the desirable properties of alnico but is more rugged thermally (still not as bullet-proof as a ceramic magnet, though). Cost is in between alnico and ceramics, but neodymium magnets can be made much smaller and lighter than comparable alnico and ceramic magnets which can reduce manufacturing and shipping costs.
a friend of mine back in the day had these utah speakers. they were not audiophile level speakers. they were efficient and played very loud, but i don't think they would be worth restoring like some classic jbl's.