T/S parameters for vintage CTS 8x10 drivers?

Discussion in 'Amps [BG]' started by kringle77, Sep 10, 2012.


  1. kringle77

    kringle77 Supporting Member

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    Does anyone on here have the actual T/S parameters for the speakers that were loaded in the vintage ampeg 8x10 cabs? The one everyone raves about. If so, could you post them on this thread please?
  2. JimmyM

    JimmyM Supporting Member

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    I've looked and never found them, but honestly, it will likely sour you on them for bass usage if you knew ;)
  3. 1958Bassman

    1958Bassman

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    Look on audio forums like Audioholics, Audio Karma and the Parts Express speaker builder forum to ask if anyone near you has a Dayton Audio WT3 woofer tester. If they have one, you can test the driver(s) and get all of the parameters, including Vas. You'll need to use rope caulk or something like it to add weight to the cone for the Vas measurement. The newest version also does rub and buzz testing, so if you have doubts about one or more drivers, you would test a known good one, then test the others. If you think you'll need to do more of this kind of testing in the future, you might consider buying this. I have one and, apparently, it works- the drivers I tested sound great with the boxes and crossovers that were designed around the parameters.

    http://www.parts-express.com/pe/showdetl.cfm?partnumber=390-804
  4. kringle77

    kringle77 Supporting Member

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    I have a rough idea what they would look like but, I really do want the specs. It would be good for as a reference on here. I had both the current weber bass drivers and wasn't super impressed. I was really unimpressed that they supposedly didn't have that information. Bull*it. If you have the parameters, you know what to do for a cab. Anyway, I just want to find the parameters. Someone who does a recone for these may know. I've thought about buying one vintage CTS just to have as a comparison.
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  6. beans-on-toast

    beans-on-toast Supporting Member

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    Not CTS specs but there are some measurements from a vintage Eminence reported in this thread.
  7. kringle77

    kringle77 Supporting Member

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    Thanks for the link!
  8. kringle77

    kringle77 Supporting Member

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    I just ran different versions of cabs, changing some of the variables around and I got either a cab that had way more low end than it should or way less than it probably has so, I guess that Im still pretty useless with winisd. If someone like johnk who has a vintage svt and RTA gear could measure his cab, that would be an eye opener I think.
  9. kringle77

    kringle77 Supporting Member

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    I just bought an old CTS 10" driver on e-bay and will have it next week. If someone who has the proper gear to test it, I would probably send it to them to get the specs. Good things to know. I can also compare it directly to the other 10's I have to see which is closest sounding. So, if someone has the gear and wants to do this, let me know.
  10. 1958Bassman

    1958Bassman

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    If these are more than about 30 years old, I wouldn't bet that the parameters were A) as complete as they are now and B) used, at all. A lot of stereo speakers were designed through ball-park guesses and listening tests until about 1980 and I doubt guitar/bass amplifier manufacturers did much more than decide that they wanted their cabinets to be a certain size, based on how it looked with the head. Also, if they're old enough, they may well have moved on and tossed the info- the original speakers' parameters aren't the same as they were back then (because of age) and, since they aren't making cabinets for them, they don't need the specs.

    As I posted, look for someone who has the woofer tester. Maybe a local car stereo shop has one.
  11. kringle77

    kringle77 Supporting Member

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    I'm really wondering how close an eminence alpha 10 would be if the paper dust cap was replaced with a screen? That may be a good idea as a closer sounding version than the B810.
  12. JGR

    JGR The "G" is for Gustav Supporting Member

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    Cool idea, I hope it works out/look foward to the results. Suprised more folks haven't already done this.
  13. kringle77

    kringle77 Supporting Member

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    Rather than remove the cap from the alpha which I can still sell, I removed the cap off an old bergantino nv610 driver that I had that was given to me for free by another TB member it had been repaired and wasn't really worth anything. Removing the cap did actually make the top end more open and smooth. But, the driver is rear vented and now wouldn't be useful in a sealed cab. Is there anyway to seal that vent up that would be reliable and not hurt the driver? I think that I may try it with the alpha after I order a cloth dust cap.
  14. kringle77

    kringle77 Supporting Member

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    I got the vintage CTS 10" last night.

    It has the exact same low end profile as the NV610 drivers so, Jim got that part right. Tight, no flub, probably a slight boost at around 150hz.

    The midrange was actually alittle scooped sounding on the CTS and this is where the berg driver just pours it on. The CTS sounded more like the B810 in the mids. I wasn't expecting that and remember it having more going on but, I haven't heard a vintage 8x10 in a long time and this is after all a 40 year old driver.

    The cts has a clearer top end than the berg and it goes higher where the berg has a nasty sounding spike at around2.5k or 3k. The B810 had a similar top end actually but, since it is a larger voice coil, it doesn't sound as sweet. The frequencies are there, but it doesn't sound as nice.

    This particular CTS driver sounded more scooped in the mids and light in the top end than I expected. I thought it would sound alittle more like a jensen mod10-50 with better low end. I wish there was a driver out there that had the mids of modern eminence drivers but had the same low end as the CTS. I've moddeled a pile of drivers and sealed, they all have a bigger low end without the 150hz bump. This just creates a muddier sound in a sealed cab and I don't like it. If eminence would have made the B810 with less xmax or a tighter bottom, they would have been pretty close to the CTS but, maybe better. The berg with the dust cap removed sounds close to the CTS but with better upper mids. I actually think that if Jim used a different dust cap to soften that upper mid clack and open up the top end alittle, he would have created the perfect sealed 10" driver.

    The faital pro 10fe200 is actually brighter but, then has the larger low end which I don't care for. You can eq all you want but, the driver has to have a particular character to start with for this sound. If someone built an 8x10 using the six berg drivers crossed over to a pair of mod10-50's, they probably would have the best of everything. Of course, Jim won't sell the drivers like that.

    Oh, from what I remember about the weber 10fl which is supposed to be a CTS clone, it sounds pretty much the same. It may have actually sounded better because it was brand new and didn't sound tired. I probably should have held on to it but, I don't like owning parts that take so long to get and that are so overpriced. That being said, I still may get a few of them in the future. I actually really liked the sound of the 10FH drivers but at 10lbs each, Im not moving a cab loaded with them. The other thing about webber that bothered me is that they claim to not have any of the T/s parameteres so, you can't design a cab around them. BS

    I don't think the driver I want is even out there.
  15. beans-on-toast

    beans-on-toast Supporting Member

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    What ever happened to the weber ABA10, an alnico version of the original CTS 10 that ampeg used. They still have it on their web site for $100 but not available.

    I wonder if adding a ring of dope around the edge of the B810 would give you the firmer the low end that you are looking for.

    As I see it, the problem with getting speakers from Berg is that if you ever need a re-cone and they are no longer carrying the speaker, you would be out of luck getting the proper re-cone kit. No problem getting CTS or eminence re-cone kits as there are a lot more of those drivers out there so they are supported.
  16. will33

    will33

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    Cool comparisons, man.

    Only thing I'd really have to add, and really, you've already hit on this, is the age of the CTS. After 40 years, it's suspension compliance is going to be way softer than it was new, or what a recone would be, even after initial break in. That would bring in the low end, might be a little of the "more bass 'sounds like' scooped mids" thing.

    That really all I can think of. As always, trust your ears.


    One other thing re: the power handling/voice coils, etc. of stuff like the Berg and the B810. People use immensely powerful amplifiers nowdays, the drivers have to stand up to that. In 1970, 300 watts was a huge amp, nowdays it's about considered "entry level" as far as a gig rig.


    If you can get ahold of somebody with a tester, it would be way cool to see the specs on those CTS's. Even better, the comparison between a 40 year old original driver compared to a freshly broken in recone.


    Good luck on this one.
  17. kringle77

    kringle77 Supporting Member

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    If anyone who has a tester would like to get the T/S parameters for the talkbass community, let me know and I'll ship you this CTS. I only bought it as a reference anyway.

    I guess that if I was going to build a true vintage 8x10 from scratch, I'd just buy the weber 10fl drivers. They really did sound like this CTS but newer so, everthing sounded a bit more crisp.

    Here is a question about sensativity. If you have an 8ohm 96db driver, the same 32ohm version of that driver would relatively be 90db right? So, an 8x10 with the 32ohm version would be about 99db while an 8x10 loaded with the 8ohm version in series/parallel would be 102db. Right? So, if you wanted a more efficient cab you would use 8ohm drivers right?
  18. Terence Cross

    Terence Cross

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    Intresting thread Kringle77!! I´ve followed your previous endeavours with interest, and know that you have previously owned and have had hands-on experience with the Jensen mod 10”.
    Bill F always regarded the Jensen as in the same ball-park as the CTS, and from what I can gather the Jensen has a poor bottom-end response with a slight mid scoop and is perhaps maginally brighter than the CTS. In your opinion how does the Jensen fare in comparison with your newly acquired CTS driver? Is it a close, or a very distant relative?:D

    Thanks Mate!
  19. kringle77

    kringle77 Supporting Member

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    The jensen sounds brighter up top because of the 2-3k spike that rolls off at 4k. It also has big low mid bump. The bump and spike create a pretty big scoop at around 300hz, which actually doesn't sound bad. The CTS is smoother all around with a fuller bottom end. If I was going to load an 8x10, I might actually use 6 cts/webers and 2 mods. The mods just sound more agressive but thinner. The low mid bump sounds good though. The cts has a low mid bump in the same area but also more lows after that.
  20. will33

    will33

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    You change one spec, you affect the others. But, it's possible the 2 versions could have the same 1w/1m sensitivity. The difference being, in an SS amp, the 32ohmer would draw much less power from the amp, so you'd have to turn up higher to feed it the same power as it would the 8ohm at a lower volume setting. It's about the power input in that case and not the actual driver sensitivity. With a tube amp, that issue would pretty much be negated, but I don't know of any that have a 32ohm tap for doing single driver comparisons. When using your SS amp, you'd measure the voltage swing at the output to ensure both drivers were recieving the same 1 watt.
  21. will33

    will33

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    Put four 32ohmers all in parallel and four 8ohmers in series/parallel and you're back to the same power draw again, though there might be a slight difference in top end due to the differing coil inductance between the 2.

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