I thought speaker mounting holes were standardized?

[drewl]

Replacing a 12" Marshall Celestion in a Trace Elliot Tramp with an Eminence Red Coat "Tonker"..(Yeah, I got your Tonker right here..) and the mounting holes don't line up, as in the outer dimensions of the speaker are smaller..

Anyone come across this before?

[R.G.]

Yep. Been there.

Nope, they're not standardized, just mostly overlap. No standards exist, I think.

[Prairie Dawg]

Really, I betcha there was a RETMA standard.

[drewl]

"RETMA"???
Return Material Authorization?

[Krwkka]

Mounting Hole Spacing

Here are a few measurements I took from manufacturers' specs:

295.4mm Eminence 12" Guitar Speaker

293.8mm Eminence 12" Pro Speaker

297mm Celestion 12" Guitar Speaker

293.5 Jensen 12" Guitar Speaker

[Prairie Dawg]

"RETMA"???
Return Material Authorization?

Radio Electronics & Television Manufacturers Assn now EIA

[Metro]

I replaced a blown Ashdown 10" speaker with a slightly uprated ebay one, cant remember the name of it. The cast basket was a bit too big to fit in the original cab route and the cast basket cant be squeezed in. I had to re-route 3mm all the way round, for 6mm diameter increase. Bit of a pain for a quick job.

[drewl]

I hear ya.....quick job, ha!

Luckily just making the mounting holes a bit larger was enough for it to mount easily.

[J M Fahey]

I'm measuring 296mm on a "Fender" generic Eminence and 300mm on the ones I make.

[jrfrond]

One of the most overlooked (and most-omitted) speaker specs is "cutout diameter". For a given size, you will find this spec all over the map. Screw holes too. It's just the way it is.

When I replace garbage Chinese drivers with decent ones, very often, the holes don't line up, and it's a bigger pain when tee-nuts are used. Most times, I will tap out the tee-nuts (half of them usually fall out anyway), offset the holes by 2" or so, and screw right into the wood with #8 or #10 wood screws. However, when ordering, I will usually pay attention to the cutout spec, and dig to find it out if I have to, then put it in our parts database where I have a section for specs, to avoid the time-wasting trial-and-error thing.