can you help me identify this UNIVERSITY 15" woofer, and if it's wired correctly?

[tofu]

it seems to look a lot like this

except the back part is removed. i think this was done due to size constraints. that back part was just some kind of magnetic shielding, correct? there is a big magnet exposed now.

anyhow. there is a terminal on the speaker and it is wired like so --

i'm not sure how this is supposed to work. i'm wondering if the previous owner wired this thing correctly for my la scala. i dont understand what those black wires are for.

thank you.

edit: the blue wires are the + - inputs for the woofer. the wires go all the way up the doghouse into the hf section to connect to my crossover.

[mungkiman]

it appears the strapping is correct, but the connection is wrong (1&4). move the blue(red) to terminal #2 and you should be fine. great woofers!

[tofu]

wow! im glad you caught that right before i screwed the bottom back on. thanks a lot.

whew.. this is a real pain in the *** without a screw gun (battery died)

[tofu]

now that i think about it.. i wonder if there was a reason they were wired this way

[mungkiman]

I think the previous owner got it half right.

[mungkiman]

Oh yes, it looks a lot like a C15W woofer.

[WMcD]

This appears to be a woofer with two voice coils. I've never played with one.

It appears the two left (1 and 2) are for one voice coil, and the two right (3 and 4) are for the second.

The wiring system described is fairly simple in principle. You are either wiring them in parallel for a low total or in series for a high total impedance.

The strapping shown in the drawing is obviously for parallel. This is what I'd start with for an LS.

The wiring to the amp shown in the diagram is not what is described as what you should do. I.e. connection to 1 and 2 is suggested, rather than 1 and 4. However, it is electrically equivalent. This is because 2 is strapped to 4. So it doesn't matter.

There is a potential issue in another sense. It is not shown which of the pairs are considered positive or red. Either 1 and 3 are plus or red, or 2 and 4 are plus or red. This may be shown someplace. (My use of "or" might be confusing. I mean that plus terminals are marked as plus + and they are also sometimes marked with red.)

In all LS schematics I've seen the plus side of the woofer goes to the plus side of the crossover. There is no polarity inversion.

Best,

Gil

[mungkiman]

1&3 are negative. 2&4 are positive.

Gil, would 3&4 work, as 1 is strapped to 3?

[WMcD]

Yes, that will work too.

The so called strapping is just to set up a parallel circuit. Both positives of the V.C.s are connected to each other and both negatives are connected to each other. So it doesn't matter where you feed them.

There is no magic to this. I certainly don't mean to be haughty. The parallel and series circuitry is one of the basic things to learn in electronics. A stepping stone to larger understanding.

The same sort of parallel strapping is used on the Klipsch speakers which can be bi-wired. I don't see any merit to it, but that is up to the owner.

In those speakers it is the woofer and tweeter (at least before the crossover) are strapped together at the input with some sort of brass strips. You can connect the feed from the amp to either as long as the strips are in place.

- - -

Back to the original subject. The wiring shown indicates to me that the previous owner did know what he was doing. I can't see any advantage either way . . . except that it spreads out the connections which will avoid the possiblity that stray strands can short out.

Best,

Gil

[triceratops]

I have a pair of these University C15W's. It is my understanding that the C15W's were used in some early Khorns. They are very substantial looking speakers with cast basket, etc. Mine are an older paint scheme, metallic green and gold. The bad news is, I tried to load them into some 70's era LaScalas and they wouldn't fit! The flange on the cast basket was a little wider than the stamped steel flange on the familiar K-33's and the LaScala cabinet comes right up aginst the woofer flange. It's nothing you couldn't fix with a chisel, but I couldn't go that far with the experiment. I'll probably bolt them into some Khorns or Cornwalls where the space is not so tight!

best in horns,

triceratops

[tofu]

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On 6/16/2005 11:06:32 AM triceratops wrote:

I have a pair of these University C15W's. It is my understanding that the C15W's were used in some early Khorns. They are very substantial looking speakers with cast basket, etc. Mine are an older paint scheme, metallic green and gold. The bad news is, I tried to load them into some 70's era LaScalas and they wouldn't fit! The flange on the cast basket was a little wider than the stamped steel flange on the familiar K-33's and the LaScala cabinet comes right up aginst the woofer flange. It's nothing you couldn't fix with a chisel, but I couldn't go that far with the experiment. I'll probably bolt them into some Khorns or Cornwalls where the space is not so tight!

best in horns,

triceratops

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the insides of the doghouse were shaved a bit on the sides to fit it in. i wonder if this was an actual improvement over the stock woofers

[CaptnBob]

The coffee can on the back was pretty much a cosmetic thing. As was noted above the C-15W had dual voice coils - wire them in parallel for 4 ohms, wire just one for 8 ohms, or wire them in series for 16 ohms. Wire them out of phase for nothing. I seem to recall, too, you could hook an amp up to each voice coil and get a center channel, but that could just be my memory playing tricks on me again.