What's wrong with my speaker?

[sprinter]

Hi,

As with art, I don't know much about about speakers, but I know what I like.

I'm resurrecting a vintage set of bass reflex speakers which house Electro Voice 12TRXB coaxial drivers. I think they sound very good, except that one seems to have a problem which I can't identify. The first thing I noticed is that one sounded quieter than the other and I had to boost it about 3dB, but it still didn't sound right. Next, I put pink noise from my amp into them and the bad one sounds different, not as bright, or mushier, like it is lacking high frequencies or something. I don't know how else to describe it, but I was hoping you could give my some direction to go in identifying the problem. I don't mind doing some basic work on them myself, but I don't want to just dive into a project without first identifying what has to be done. There are no obvious distortions, crackling, buzzing or anything. Just poor sound. They also have never been abused or overworked, but they may be >20 years old.

Later: Listening closely with music, it is definitely losing a lot of treble and position of the crossover pot has no affect at all.

What does this sound like?

[CLS]

The magnet is probably loosing its strength.

[lowpoke]

It sounds like there's a problem with one of the high frequency drivers not functioning correctly, or at all. Have you checked any connections to the unit in the centre?

[steviedon]

From my understanding this particular model was produced for a long...long time by EV. Thusly, there are a few different iterations of it. Investigating further would require determining whether you have the version with the pressed in tweeter and horn, or the one that can be disassembled and the diaphragm and coil replaced on the tweeter (there will be two screws underneath the horn if so), as it sounds like the tweeter is done. I may be wrong but I think the earlier versions with bronze colored baskets had the pressed in horn and tweeter assembly, and the later with the stouter white baskets had the other. Or, it could be as simple as a failed component in the crossover network, in which case ID the part and replace.

[adason]

I would have a look at the tweeter crossover in the defective unit
especially that pot..it may not have contact anymore

[sprinter]

Thanks for the replies. It looks like the horn is pressed in, but in listening more closely, there are some highs coming out and the crossover does have some effect, just not enough and I need about 3dB more power to it to match the other one. It's not terrible, but I guess I'll be looking for a new driver.

In fact, the cabinet was designed for 15's in mind because the front baffle is cut for 15" and the 12's are mounted on a smaller baffle screwed to the front one, so I may look for some 15" versions, which should be pretty nice.. The cabinets have a bass port on the front baffle and are about 4.3 cu.ft. Is that big enough for a 15? They are 20-1/2 wide, 23-1/2 tall, 15-1/2 deep (inside). I would like to stick with either an axial driver or a single full range, but I suppose full range is pretty hard to get in a 15", right? Or do you think it's even worth going to 15"? I don't play loud, but I know that in guitar amps, I usually like 15's better than 12 even at lower levels.

Any suggestions for a new driver are welcome!

I should mention that my amp is not a tube-type (sniff). The EV's are rated at 52dB RETMA. I think that translates to 101 now. Would that be right?

Ron

[Badwater]

Rebuild the crossover and you will be in heaven. Great driver. Once you get it sorted out put them on a pair of open baffles paired with Alpha 15As and you won't look back.

[lowpoke]

Originally Posted by Badwater

Rebuild the crossover and you will be in heaven. Great driver. Once you get it sorted out put them on a pair of open baffles paired with Alpha 15As and you won't look back.

x 2

[kbgl]

Would you guys know anything about a Electro Voice Wolverine LS-12 driver?

[sprinter]

Originally Posted by Badwater

Rebuild the crossover and you will be in heaven. Great driver. Once you get it sorted out put them on a pair of open baffles paired with Alpha 15As and you won't look back.

Great suggestion. Remember, though, I'm really new to this stuff. How do I go about rebuilding the crossover? I don't even know how to get into this thing. Can you help get me started? I don't mind doing it, I'm just in unfamiliar territory here. How can I tell what has to be done once I'm into it?

On to the baffles. Are you suggesting that I ditch the cabinets altogether and build a new open baffle? I'm willing to do that, but I'm not sure what you meant. Or did you mean to use the cabinets open-backed? Or is that a no-no? There actually would be room for a 15" above the EV on the front baffle in the cabinet.

I know nothing about open baffles right now, but I'm anxious to learn about it. I'll do some research. Meantime, I'd love to hear any suggestions on a good baffle arrangement for this situation. I am an experimenter at heart anyway.

Thanks.