I picked this speaker up at a garadge sale 2 years ago and now im thinking about useing it. The only problem is, i dont know what it is. The thing is massive with a huge magnet on it. I think its a bass speaker of some sort. The sticker on the botom of it is gone so i have no idea what it is rated for. Here are some pictures. The smaller speaker is an 8" speaker for scale.







The blue thing is a 12" ruler (30cm).

Looks like a 15" woofer to me. Probably used in a car. Without detailed specs, it will be hard to design a box for it and make it sound good (assuming it had that capability to begin wi9th), but you could always just throw it in a sealed 3 cu. ft. box for sh**ts and giggles.

I guess i can try that. So from the looks it is probably 4 ohm then? My stereo already has 2 10" woofers (soon to be 4) so im not sure if adding a 15" would do much. maby i could turn it into a tactile transducer? then sound quality wouldent matter. and by the loks of it it has a magnet that could lift a house.

Im thinking thats a PA speaker.
Im bettin 8ohms.
One way you might be able to identify it is to look at the basket and see if it has an serials or identifying marks on it. Its a stamped basket so its not incredibly high end, but they sometimes stamp identifiers on them when they make them. That spider is pretty thick so Im guessing its a long excursion. It was probably part of a reinforcement bank for a mobile system. May have been part of a big bank too, since it has the horn mount in it. Tough to say. Could have also been a standalone for an EG.
One thing you might try is bringing it to a local music shop thats heavy on guitars and see if anyone recognizes it.

Without knowing its exact specs, you will only be able to come "fairly close" to getting the bass it can produce, but if you find them, then you can build an enclosure for it and have some lovely boom!

Then again, maybe something like this would be even more fun...


Check for marks and get back to us. Maybe we can figure out what it is...

I have serched it quite theroly and havent been able to find anything on the speaker. The onlything on it that is still there is on the sticker there is a 20 or a Z0, i cant figure out what it is. But thats it. I was defently thinking of the sonotube bass to put in the corner. That would complement my system nicely.

You will probably have a tough time tuning this one without the specs to go with it. I looked for variations on what that sticker code could be. Didnt find anything very significant except that the 20 might stand for a 20 mm voice coil or the standoff section for mounting a horn. If I were to give it my best guess. I would say that is an 8Ohm speaker from a PA system or electic guitar amp. The amount of resources you COULD waste in getting it to be accurate would outweigh the cost of the piece itself in a matter of minutes.

My advice to you is to sell it, get back some money, and go buy a woofer with specs you can verify from someplace like PartsExpress. It will save you a LOT of hassle, frustration, and wasted resources.


On the other hand, finding a similar one and building a rough box might give some sense of thump and bump...

I’d say it was a car speaker, probably 4 ohms. If you have a multi-meter you could simply measure its resistance. It looks to be a high compliance type driver (large rolled suspension). You could measure its specs but it will require some test equipment. Just stick it in a sealed enclosure as this type of box is the most forgiving. If the bass sounds weak, make it larger. If it sounds boomy, make it smaller.
And I would think about sealing up the voice coil, someone has removed the dust cap.

DJ

From the looks of it it seems like putting it in box and hooking it up is the best way to find if it is usefull or not so i will give that a try. If it doesnt work i didnt waist much because the speaker cost me $1. Will any damage be done to my amp if it does turn out to be 4ohm? My amp is made for 8ohm equipment.

Dazz,
As far as I know, they have never made a woofer/sub for cars that had a removable core. That would allow dust and contaminiants to get into the VC. Look closely at the picture and you will see it goes all the way through to the back. You can also see the coil windongs on the side shot. Way too exposed. I think we are looking at a coaxial PA speaker that has had the compression driver and horn array removed from the mount. Having this hole would nullify the effect of putting it in a sealed enclosure and I doubt they would have sealed this with just a sticker. That would just come off in a sealed as soon as it hit a nice big note.

Really curious to see what this thing is...I cant shake the feeling that its an eminence replacment driver.

Depending on how you amp is made it might be okay with 4 ohms. Mine handles both 4, 6 and 8 ohm loads. It would probably be okay to run it at 4ohm for a little while to test, but unless your amp is rated for 4, it will strain the amp a bit. Might even lead to overheating. Or it might trip the reset on the amp.

1 buck? Hehehe. Take out the cone and make it into a cool lampshade!

SJ, it could have been sealed because from the looks of it there is a residu left from where the dust cap used to be.



It also has these conectors on it which is why i think its a car speaker.

The other day i bought two of these speakers.





Now, my plan is to make these my rear chanel speakers, but i am going to take the drivers and crossover out of these boxes and build new ones. What i want to do, i dont know if this will work, is take the woofers and put them in their own sealed boxes on the floor and then take the twetter and midrange and the crossover an put them in another box that i will mount on the wall, then i will run wiers from the crossover to the woofer on the floor. Will that work?

Ok, last questions for now, i have two of these speakers.



This is the midrange from one of them.



Both of them have a slight problem



I want to replace them but i have never seen a driver like this befor. the back is sealed in its own metal case.



Ok, now for the questions. First, cant i replace it? second, can i get one that is sealed like this one? third, since it is sealed am i corect in thinking that it doesnt matter what size the enclosure for it is? forth, how would a speaker rip like that? noone ever did anything to it it just riped one day.

I’ll have to disagree on this one.
What I see when looking at the photo is not a removable pole pieces but a vented pole piece. High compliance drivers like this have very large cone travel so they vent the space under the dust cap and around the voice coil from the rear. This greatly reduces distortion from trapped air. The vent also helps coil the voice coil as an added bonus. Some driver designs even vent the space under the spider for the same reasons. Another thing that tips it to be a high compliance driver is the raised backing plate around the vent. This allows extra room for the voice coil to travel. I doubt the original sticker covered this vent and probably just encompassed it. When the dust cap is in place it essentially becomes part of the cone sealing the front from the rear. Not allot of PA drivers use a single roll rubber suspension.

DJ

Edit:
I just noticed on x 25’s pic of the binding posts that there is a vent for the spider as well.

When i just took the new pictures of it i atually found vents arouund the spider so it seems to be a high compliance driver. Now what is a high compliance driver?

Generally they are used in sealed enclosures but since the trend for car HiFi some drivers have been designed for free air mounting (no box). Without actually measuring the specs it is difficult to tell. Best bet would be to replace the dust cap and stick it in a sealed box.

DJ

I cant really say that agree or disagree. My curiosity is basically about what it actually is. This speaker could be one of the early kilomax line from eminence or it could be a car woofer. But looking at the outer spider, its hard to say. I know we sometimes get double layers ones that have a complex spider covered by a butyl rubber cover, but I dont see anything different on the other side. Lean that one towards the 4 ohm side of life. But the contacts on the woofer arent anything that isnt seen on higher end PA models and there are some out there designed for harsh climate. Then again the amount of rust on the metal shows it to be reasonably old. I think the venting idea could be right. Perhaps the filter cap was connected to a peice of metal that is now missing?. The residue definitely looks there was something there although the size could be either a sealer around a vent or a dust cap. Im kinda torn between both sides now but I do have one more suggestion that MIGHT fit the bill....what if that was the woofer from an infinite baffle system?

The used stamped steel frames on a lot of those drivers and the butyl surround would provide the excursion needed. Picture that bad boy in an attic or basement ( a moist basement would have helped the corrosion along...) pumping out bass to its attached room..

Sorry dont mean to belabor the point, Im just really curious what it is!

Think you can get a resistance reading on it so I can sleep tonight? Daz, gonna need your address in case I need to send you a snickers bar!

Welcom to my world, half the stuff i own i dont know what it is, i just know it works.

anyway, if i just hooked it up like it is know would that harm anything? i just figure ill hook it up and see what it sounds like. If i just hooked it up without a crossover right to my amp would that harm anything? And if anyone missed it i posted some quetions about some other speakers a little firther up.

EDIT- i looked on the speaker again and there are no identifying marks, ill take a picture of whats left of the sticker a little later. I did knowtice that there is a reuber ring covering the main magnet, i took it off and besides the magnet there was nothing under it.

I've got an eminence beta 15", it has the same type of rubber thing around the magnet, but it has a thinner paper cone and a spider-like surround. It's supposed to be for a guitar cabinet I think.

I hope i can get this speaker working. My one set of speakers peeks in the bass at 50hz, the other at 100hz, and between the two sets they cover everything nicly up to about 18,000hz. The only thing i am missing is the sub 40hz.

Get any resistance readings?

Is there a special way to do that on a speaker?

Sorry for the delay. Do you have access to a multimeter, specifically one that can measure resistance (ohms)?

Yeh, my dad has one, but i thought ac impeedance was different from regular resistance.

You need one that can be set for DC. Try testing just the two speaker terminals. Im guessing you get slightly over 3 ohms.

This is going to throw you for a loop SJ, i got 6.33 Kilo ohms

Two possibilities:
1. You have made a typo and it should read, 6.33 ohms. In which case the driver is an 8 ohm.
2. The resistance is 6.33 kilo ohms (6k33ohm). Then it’s probably got a burnt coil with some leakage.

DJ

I guess i have to go with the second one because there is a k before the ohm symbole on the mutimeter and it is there only when connected to the speaker. Ill go double check my settings though.

Try connecting it to a 1.5V battery briefly. The cone should move in or out depending on the polarity

went and check the settings and they are right, here is a picture of the readout. See the K before the ohm sign?



Also, i tryed the batery, i dont think its enfough to make the cone move but i could her crackling every time i conected or disconected the battery. I also played some music threw the speaker by conecting it to a headphone amp and then pluging the amp into my mp3 player.

definately a car sub. The connectors and the foam surround are both characteristics of car subs( I know foam surrounds are common, but the other idea was guitar speaker, and as a guitarist and semi experienced guitar cab builder, I have NEVER seen a foam surround or those type connectors used.) Also, guitar/bass speakers are not hi-fi...hi-fi speakers would NOT sound good with a guitar played directly through them. Even P.A. speakers are usually cloth surrounds or something(accordian type maybe?) but not foam.