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Looking for specs for 12" CTS woofer(repost)

Vintage Bert

Vintage Bert

Opinions my own, except those of the Mothership!
My quest for some info has died in DIY so I am reposting here.

Trying to calculate sealed volume for 12 inch CTS driver (1973,14th week) can't find specs for it anywhere yet...the cabinet it came out of had them in about 1.7 cubic ft sealed compartments. Trying to determine if this was just random or actually calibrated.

Guessing someone here knows more than the internet.

Do the various 12 inch of that era vary greatly?

Thanks in advance.
 
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I doubt you will get the specs you need (T/S parameters) to do what you want. They were not available at that time. I built some speakers in the early 70s using CTS drivers. In addition to building drivers for speaker manufacturers, CTS sold some directly to the public for DIYers. I still have the CTS brochures. They list two 12 inch woofers for home builders, a 12W19P and 12W54C. The 12W means 12 inch woofer, the following numbers are the magnet weight and P is foam surround and C is cloth. The CTS designs show a 26.5x14.5x10 sealed cabinet for the 12W19P. The 12W54C design is vented with a 18x14.5x10 box with a 6.7" long x 2.5" ID duct. Hope this sheds some light on things.
 
I'd cruise over to techtalk on parts express and see if there's any serious DIYer in your neck of the woods with a woofer tester to be able to determine the T/S parameters of your actual drivers.
 
JimHRB, would you be able to scan and post a link to those brochures? Might be interesting to some of us here, especially since CTS was such a big supplier back in the day. I recall a pair of speakers I built using generic 12 speakers with whizzer cones, stamped frames, and black accordion cloth surrounds; I wonder now if they were CTS. I think the brand name on them was Federated. I didn't have enough money to get tweeters or crossovers (and didn't really know anything about them), but I remember those speakers sounded wonderful and could handle big volume from my Sherwood 7100A receiver.
 
alteclipsch said:
JimHRB, would you be able to scan and post a link to those brochures? Might be interesting to some of us here, especially since CTS was such a big supplier back in the day. I recall a pair of speakers I built using generic 12 speakers with whizzer cones, stamped frames, and black accordion cloth surrounds; I wonder now if they were CTS. I think the brand name on them was Federated. I didn't have enough money to get tweeters or crossovers (and didn't really know anything about them), but I remember those speakers sounded wonderful and could handle big volume from my Sherwood 7100A receiver.
Click to expand...
Boy, does that sound familiar. Anyone 50-60 or older probably started with the same type of speaker system.
 
And unfortuantely, I'm over 60. But I do remember how great those speakers sounded. It's likely they wouldn't compare to my current Altec Valencias or Klipsch Heresys.
 
Vintage Bert said:
My quest for some info has died in DIY so I am reposting here.

Trying to calculate sealed volume for 12 inch CTS driver (1973,14th week) can't find specs for it anywhere yet...the cabinet it came out of had them in about 1.7 cubic ft sealed compartments. Trying to determine if this was just random or actually calibrated.

Guessing someone here knows more than the internet.

Do the various 12 inch of that era vary greatly?

Thanks in advance.
Click to expand...
I'll check my drivers. I think they're CTS. Pretty sure those cabinets are WAY undersized.
 
alteclipsch said:
JimHRB, would you be able to scan and post a link to those brochures? Might be interesting to some of us here, especially since CTS was such a big supplier back in the day.
Click to expand...

I'll second that request. A long long time ago (1973-ish), I was a rep for CTS and I had those brochures, along with a complete OEM catalog, but many years and several moves later they're gone. I'm sure loads of speaker folks on here would be eternally grateful for some scans.

Happy trails,
Larry B.
 
1tumbleweed said:
I'll second that request. A long long time ago (1973-ish), I was a rep for CTS and I had those brochures, along with a complete OEM catalog, but many years and several moves later they're gone. I'm sure loads of speaker folks on here would be eternally grateful for some scans.

Happy trails,
Larry B.
Click to expand...

If you were a rep for CTS, do you recall if they OEM'd speakers for Herald or Federated? I think Federated was in Chicago---and I've heard CTS was, too.
 
alteclipsch said:
If you were a rep for CTS, do you recall if they OEM'd speakers for Herald or Federated? I think Federated was in Chicago---and I've heard CTS was, too.
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CTS - whose name was originally Chicago Telephone Supply - had their hand in lots of different businesses, all mostly electronics related. The speaker manufacturing division was in Paducah, KY.

I know/knew very little about the OEM side of things, I was a rep strictly for dealers. Although I did have a copy of the OEM design book, all I called on was little stereo shops and parts places. I had one dealer who bought quite a lot from me, selling raw speakers as well as complete systems he designed and built in-store. It's a shame that that type of "do-it-yourselfer" type of business has almost entirely vanished.

Happy trails,
Larry B.
 
1tumbleweed said:
I'll second that request. A long long time ago (1973-ish), I was a rep for CTS and I had those brochures, along with a complete OEM catalog, but many years and several moves later they're gone. I'm sure loads of speaker folks on here would be eternally grateful for some scans.

Happy trails,
Larry B.
Click to expand...

Sounds like there's some interest in scans of the CTS brochures. I should have some time in the next day or two to do that. Haven't uploaded things to this site before, but it looks like I can directly upload a .pdf file if it isn't too large.

FWIW, the speakers I built were towers using the 12W19P woofer and the 2T8 phenolic ring tweeter using the CTS specs though I bought the drivers from a company called McGee Radio. A reproduction of that famous tweeter is available from Parts Express. Still have them though they were retired a couple of years ago when a built a pair of Zaph Audio BAMTMs.
 
If you like and will cover shipping, I will offer my woofer tester, Dayton Audio DATS measurement to measure your woofers. It will get your T/S parameters for the proper start to build around those woofers. No charge to do this for you, just PM me if you like.
DC
 
dc270 said:
If you like and will cover shipping, I will offer my woofer tester, Dayton Audio DATS measurement to measure your woofers. It will get your T/S parameters for the proper start to build around those woofers. No charge to do this for you, just PM me if you like.
DC
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I can do the same. Might be closer to me, which would save some on shipping. I offered, a long time ago, to run DATS on drivers FREE for anyone who wants to. You know, maybe we should have a sticky and AKers around the globe can post in the sticky if they are willing to do this for other AKers, but only if they'll do it for free (not including shipping). That would be an awesome "service" since so many of us deal with speakers for which T/S specs aren't published.
 
This is a great thread, and thank you members for offering to test the drivers for free. There were a lot of CTS drivers produced and used years ago and it would be great to compile some type of reference data for them in one place, be it here or more than likely a sticky. :thmbsp:
 
Actually the Dayton DTS system does a lot more like measure T/S parameters, impedance, Vas, Capacitance, Inductance, Resistance, signal generator and even more!!
Best money you will send on test equipment!
DC
 
Well thanks to all for the tips and offers for testing! I am going to try and get some folks in town to come with as good an offer to run some parameters on them.

I am thinking I am going to have to stay close to the current volume for them. I looked through some specs on a bunch of other 12" drivers (eminence) and the enclosures are certainly in the average recommended range for all the ones I could find. And yes I realize there is considerable variation between the different 12" variations, but the ones I could find ranged pretty close to the volumes I already calculated from the originals...

This Dayton DTS system sounds pretty damn functional as well.
 
JimHRB said:
I doubt you will get the specs you need (T/S parameters) to do what you want. They were not available at that time. I built some speakers in the early 70s using CTS drivers. In addition to building drivers for speaker manufacturers, CTS sold some directly to the public for DIYers. I still have the CTS brochures. They list two 12 inch woofers for home builders, a 12W19P and 12W54C. The 12W means 12 inch woofer, the following numbers are the magnet weight and P is foam surround and C is cloth. The CTS designs show a 26.5x14.5x10 sealed cabinet for the 12W19P. The 12W54C design is vented with a 18x14.5x10 box with a 6.7" long x 2.5" ID duct. Hope this sheds some light on things.
Click to expand...

This is super helpful actually! The boxes I used were around 1.9 cu/ft and the sealed in your description is 2.2, certainly in the ballpark, and if the Eminence published standards are any guide, there is a range of sealed volumes that works for each speaker and 0.3 +/- is something I can live with!
 
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OK, took some time but here are the scans of the later CTS brochure I had in my files. Had to reduce the resolution to get the file size down and still had to split it into three pieces. Enjoy.
 

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