Thiele Small parameters for 'classic' speakers?

[Stub Mandrel]

Is it possible to find parameters for old speakers anywhere? I'm thinking of porting a couple of closed cabs but don't want to take apart if there's no point doing so.

What information would be needed to guesstimate the parameters - this would let me make a port and experiment with tube lengths.

[Phil Starr]

Celestion are pretty good at providing these for their speakers via email. I've not tried Eminence but it might be worth emailing them. Fane tend change the designs of their speakers whilst keeping the same name which get's confusing. If the speakers are OEM then you probably won't get any details, although Ashdown are pretty helpful generally.

If the speakers date back to the early 70's nobody will know the T/S parameters because their work only became widely known then, There were still designers in the late 70's who hadn't adapted to use them for instrument speakers.

[Chienmortbb]

I do have TS parameters fir some of the older Fane Classic range of speakers but looking at them makes you realise that speakers have come some way since then. 

[Bill Fitzmaurice]

It depends how old they are. Prior to roughly the mid 1990s they may not be available. They can be measured, but you need the tools to do so. Celestion is one of the worst. They approached me circa 2005 about recommending their drivers in my designs, but were unable to provide any specs. I don't have any specs on file from them prior to 2008, while I have specs on JBL going back to the mid 70s.

[Stub Mandrel]

Hmm... the Celestions are probably well pre-1980, they are in a Phoenix cab. I was given the Mackenzies in the late 80s, but they were probably quite old then - I just copied the Phoenix cab's dimensions.

I'll open them up and see if they have any useful markings.

[Bill Fitzmaurice]

The only way you'll get specs on those is if Celestion still makes them, and even then maybe not. They still don't publish Greenback specs, not that it matters all that much with guitar drivers.

[goingdownslow]

I had this McKenzie spec sheet from somewhere...

also Win Isd Pro (alpha) has a database of a lot of old speakers, eg...

Edited April 8, 2019 by goingdownslow

[Stub Mandrel]

Anything called WinLSD deserves downloading... 🙂

[Chienmortbb]

It is isd not LSD-but there is a learning curve and it will mess with your head.

[Stub Mandrel]

Well Loudspeaker System Design seemed  an obvious solution to the acronym!

[Stub Mandrel]

Oh well - that wasn't very productive.

The McKenzies have a black on white label "Mackenzie Professional series' and no other markings, not even a power rating. They are 12", dual cone with a voice coil perhaps 2 1/4" or 2 1/2" diameter and a seep crimson crackle finish frame.

And how on earth do spiders get inside a cabinet that is to all intents and purposes airtight and fill it with web?