Help needed repurposing vintage PA cabinets

[lowpoke]

I've inherited some vintage PA cabinets that my father (who was a violinist) had custom made in the 1970's. Each cabinet houses a 12" JBL K120 and an RCF TW25 horn tweeter.

From what I've already read on this forum already, the K120's are well regarded for use in a guitar amp. I was hoping to be able to use these in a hifi / home theatre situation.

I was also able to locate (with the help of this forum) the Thiele Small parameters for these drivers, which (with the help of somebody who actually understands this data) indicates an unfortunate UNsuitability for my intended use.

So I'm wondering whether I could repurpose these (successfully) for use in my home set up by building new cabinets that will give me a little better frequency response in the lower end, or perhaps even adding an additional driver to assist.

I suppose my real question is whether the time and effort required to retain these drivers would be better spent starting from scratch with better suited components. I do like the idea of using my father's old equipment, but only if a good result is actually attainable.

Looking around on the forum, I can see there are a good deal of you with ex PA and theatre components repurposed for home use, so hopefully somebody has some good advice for me in this department.

By the way, (unlike the enclosures) the drivers themselves are in excellent shape. They were professionally restored a few years back when I first acquired them.

[Doc Mark]

Hey, Lowpoke,

Neat that you now have your Dad's old PA setup. I inherited my Dad's old trombone, but soon found that it wasn't a good fit for me, so I gave it to my little brother, who still has it today.

I once used some 2130's, which are similar to the K120's, along with a pair of 2105's, and Peerless tweeters, for a HiFi setup. It was far and away better than the el-cheap-o stereo speakers that I had used before. BUT, it really was lacking in low bass, and the brightness of that speaker, which was really made for SR, was VERY fatiguing in short order and my ears had a hard time with that. Also, the poor little Peerless tweeters might as well not have even been in the boxes, as it didn't stand a tinker's damn of keeping up with those two JBL's!! But, that's another story...

My advice is to keep Dad's old system just as it is, and maybe use it for "outside music" at parties and such. Find a set of JBL components that were designed for HiFi usage, and cobble together a nice system using those, your ears (and you) ;) will be much more happy, in the long run. For what it's worth.... Take care, and God Bless!

Every Good Wish,
Doc

[Ducatista47]

There may be some SR components that will give appropriate service in the home theater application, I don't know. Hifi would be more of a stretch. A complete SR cabinet would need a lot of modification and fiddling.

It became clear to me, after reading the forums here for a couple of years, that many here are quite interested in do it yourself for its own sake. I personally understand the rewards of a DIY pursuit. Since you poised the question of effort vs result, I think the forums point to it being easier to pass a camel through the eye of a needle than to use a group of semi- or non-appropriate components to reach a satisfying audio playback system.

A few recones as a different driver, designing and building new crossovers and cabinets (Yikes!), marathon LEAP or CLIO work to try to get it to all perform as intended, room modifications to help it work in an inappropriate environment... I am reminded of two things. The hammer that lasted forever but needed a few new handles and a few new heads, and Bob & Ray's 1950's DIY parody of how to make your own iodine from scratch.

Refurbishing or building a known, professionally engineered design is still DIY and brings those rewards to the project, but you get to the music much sooner and the frustration level goes down 95%. And it sounds great, not like a compromise.

Bottom line, if your interest lies in the journey and the real goal is a nice tinkering experience that never quite ends (providing endless fun), then you are on the right track. But if it is indeed all about the music, as almost everyone here claims it is, the overlap with the first approach is nearly nonexistent. There is room for both, but your initial questions seem to identify you as the second type.

For instance, Greg Timbers still thinks very highly of the 250Ti. He says they sound fabulous right out of the box, no tinkering, when planted in the kind of rooms we have in our real world homes. He has even been so kind as to list improvements that can be made, right here in these forums. I sometimes wonder why they are not frequently cloned. I know some components are hard to get, but that has not stopped very many DIY-ers here before. Just don't ask me, I have never heard one. But I am always willing to take Mr. Timbers' word for it.

Clark

[BMWCCA]

For instance, Greg Timbers still thinks very highly of the 250Ti. He says they sound fabulous right out of the box, no tinkering, when planted in the kind of rooms we have in our real world homes. He has even been so kind as to list improvements that can be made, right here in these forums. I sometimes wonder why they are not frequently cloned. I know some components are hard to get, but that has not stopped very many DIY-ers here before. Just don't ask me, I have never heard one. But I am always willing to take Mr. Timbers' word for it.That was a lovely post that GT sent here. I fondly remember one part in particular which gave me the kick necessary to wade into a mine-field that regardless proved worth the effort. The last sentence is my favorite:
Before closing I should comment briefly about the 250 - 4345 comparison. Simply put, I prefer a 250. I like the bass quality of the LE14 woofer. Alway have and always will. The 2245 when used as a dedicated sub is one of the best sounding woofers ever. It has an amazing blend of speed, pitch and punch. So does the 14" but the 18" is better. Unfortunately the 18" dislike for passive networks hurts it more than the 14" is hurt by a passive network. I think the mid and high range on the 250 is smoother and much more open however the 4345 wins by a bunch in terms of effortless dynamic sound. I have made all of the above changes to 250 systems (except for separate amp on UHF) and the improvement is huge. I have not done so on the 4345 but I suspect that that system will benefit from theses changes more than a 250 would. If both systems were tweaked out to about the same level, I suspect it would be very hard to come up with a clear overall winner, but I think I might lean towards the 4345 as having the greater potential.

". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

[lowpoke]

Thank you guys,

I really appreciate your replies and completely understand your comments on whether the trip is about the journey or the destination. As much as I like tinkering, I don't find spare time as abundant as it used to be now that I have a family to enjoy and a business to run.

I think it's pretty obvious I should continue my research and locate some more appropriate components from which to base my system.
There is so much knowledge, experience and information on this site though, I'm sure it won't take me too long to work out where I'm going.

[jcrobso]

It also makes a good stage monitor speaker, but not a good low bass speaker. The suspension on the K120 is just way to stiff for good low base response.
A JBL 123A would be a good choice. John
http://cgi.ebay.com/JBL-123A-3-Woofer-12-Speakers-Model-L-100_W0QQitemZ320349447248QQcmdZViewItemQQptZVintag e_Electronics_R2?hash=item320349447248&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A10|39%3A1|240%3A1318

[BMWCCA]

The suspension on the K120 is just way to stiff for good low base response. A JBL 123A would be a good choice.
You're a very funny guy!

:rotfl: