Same model speaker - same cab - different sound. Questions...

[lonewolfsx]

Hello all

I recently picked up a 1986 Marshall 1960A cab. Inside are 4x Celestion G12T75's, and they all have the same date codes - 1986.

These cabs are mono and just have a single jack, unlike the newer cabs. To make an easy A/B test station, set it up so each pair of speakers in an X pattern are wired to their own jack. I used high quality speaker wire and push on connectors - all brand new so the original wiring can be easily restored. So I think I can rule out the wiring as the issue.

Here's my question - when using one pair of speakers, I get a much thicker, bassier sound. The other pair is brighter and not as deep sounding. But they are the same speakers - measure the same on my multimeter - same wiring, same jack etc.

Any ideas why this would be? Obviously I can't rule out that some previous owner fooled around in here or whatever and maybe only used one pair of speakers for a while or something and so those are more broken in. Is that the only possible explanation?

Thanks

 

[JohnH]

Seems odd! how about if one speaker was wired out of phase? Battery test...feel/see if all comnes move the same way if a battery is put across them.

 

[lonewolfsx]

Thanks - I'm taking the back off the cab now so I'll give it a try. That sounds plausible to me - definitely could be a phase issue now that I listen to it again

 

[pedecamp]

Thanks - I'm taking the back off the cab now so I'll give it a try. That sounds plausible to me - definitely could be a phase issue now that I listen to it again

While you got the back of the cab off look at the construction and materials, are they identical to the other cab?

 

[uselessoldman]

A cab made from MDF would sound deeper and muddier, ply is nice clean sweet yummy. But from your description its a phase issue either relating to the speaker wiring or a cable somewhere in the chain.

 

[Adieu]

Hearing?

I know eye issues can make you see different colors out of different eyes.... same thing, just with ears?

 

[lonewolfsx]

While you got the back of the cab off look at the construction and materials, are they identical to the other cab?

Sorry - should've been more clear - it's the same physical ply cab. Each pair of speakers has their own 8ohm jack now.

Maybe I'm just going crazy. But the speaker at the top left is definitely brighter/edgier than the one on the top right. I even tried turning my head side to side just to make sure it wasn't something like, one ear is more worn out than the other.

Not a big deal anyway. Just kind of odd. If I figure out what it is I'll update here but who knows, might just be manufacturer variation (the speakers are almost 35 years old too) or maybe somebody who owned it before me disconnected two speakers for a while so they are at varying stages of "broken in"

Thanks for the tips everyone.

 

[BygoneTones]

Get the speakers out and have a look at them. It sounds to me like they will probably have different cones installed. Possibly recones, or possibly original cones from different suppliers.

Another possibility is that they have something wrong with them making them sound harsher than the others.

Celestion did change parts suppliers through the years fairly regularly according to duncan boniface (ex employee there) so this can account for differences in tone within the same speaker model.

 

[lonewolfsx]

I got it figured out. First thing I did was check all of the cones, look at them all very closely for originality, looked around more and more thinking what is going on??

Then I realized I ran out of red wire part way though and had to use black for the rest. I stupidly had connected positive to positive on the second pair of speakers - it still measured the same resistance on my multimeter so I didn't realize that I had done that wrong but it makes sense now that I see it.

Anyway, I swapped those around to the correct terminals (good thing I used push on connectors) and now both pairs of speakers sound identical! Yay!

Thanks everyone for your help. Ended up all being user error at the end of it