Did you replace your Cornwall tweeters?

[moray james]

Welcome to the forum Jim: nice sounding project you have on the go. My experience for the most part with Klipsch Tweeters is limited to the K77M the CT125 and the later horizontal mount tweeters as in the Forte lineup. If you plan to use a K77 (or the CT125) diffraction style horn you should mount it vertically as that is how it was intended to be used. IIRC vertically mounted it has a dispersion of 80 degrees horizontal and 30 degrees vertical. The horns like the K79K are 90H x 40V and are very nice smooth tweeters especially with Bob's Titanium diaphragms. I did some looking but I did not see anything which was as good as the stock Klipsch tweeter for under $200.00 a pair. A used pair of B&C DE25 or DE250 compressiion drivers would likely be excellent upgrades as they are highly regarded but I woud be more tempted to try them on the mid horns if you are getting 1" throats.

There are lots of experienced builders on the forum and I am sure that you will have plenty of good advice. Good luck with your project and keep us posted as to your progress. Best regards Moray James.

[jrebman]

Hi Moray,

Thanks for the note and interesting to see you around these parts -- I always associate you with electrostats. If you don't remember me, we've met through the Planet10 guys.

Anyway, I'm not sure there is enough room in the CWs to mount the tweeters vertically, and in some ways it's a bit counterintuitive that the longer opening should have the narrower dispersion, but then again, it also sort-of makes sense.

Unfortunately, with the k77s, I do really miss the more extended response, as my tonian speakers with ribbon tweeters spoiled me and that was among the first things I noticed when I moved the CWs into my listening room. That and the lower, but much less articulate/controlled bas, and the resonance in the squawker.

In the end my aim is to have a very smooth, clean, and balanced response from 30-something hz to something more like 18 or better khz on the top and with an impedance load that can be easily driven with various 2a3/45/el84 SE amps, and do so with nice tone and great dynamics -- macro and micro.

In some ways I'm just starting this, and in others, I've been listening to these very carefully, albeit in another room and different amplification, for a year or so so do have a good idea of what I want to change/improve.

Thanks again,

Jim

[moray james]

Hey Jim: my memory for names is terrible but I am good with faces. I still love stats and horns and ribbons are a logical direction to look into. Horns ribbons and stats are the three best ways to get low distortion & dynamics. The CT125 while phenolic extends to 20KHz. and is an exact copu of the K77 horn so it too is a difffraction horn and should be mounted vertically for the widest horizontal response. Are you planning on building a new motor board or are you planning on using the existing one? The best place to position your tweeter is on top of the cabinet so the toplates of the tweeter and the mid horn driver lign up. Gotta run Best regards Moray James.

[jrebman]

Moray,

Well, we've only met in a virtual sense, so you wouldn't know what I look like either :-). And seeing as I'm totally blind, I wouldn't have any idea of what you look like, but I'm the guy who Chris built the first pair of F120A fonkens for, a few summers back, and which I believe you heard at the annual fest at Dave's place.

I have seen a number of people saying the same thing about mounting the tweeters in order to correct the time/phase alignment. I wonder how far back this means the tweeter would have to go. Is the idea to get the throats lined up?

Maybe I should start a new thread once I do a bit more research...

Anyway, the crossovers are going to be a while yet, so no rush on all of this.

Thanks again,

Jim

[moray james]

Jim: I sure do remember those little Fonkens they sounded excellent. I especially liked what the ENable treatment does for the Fostex drivers. That was a great get together a gang of audiophiles in the woods all the great coffeed Dave made and the TLC from Ruth with snacks and food just when you needed it. Was a wonderful break for me and everyone there.

I think that for the tweeters you want to align the centre of the tweeter top plate with the centre of the mid top plate. Lynn olsen did some measurements of this mod on a pair of Garry Pimm's Chorus and the before and after measurements left no doubt that this was the way to go. I wouls imagine that if you set your tweeters up with extended wires and set them on top a few minutes would have them adjusted perfectly by ear which is the best way to do it as what I suggested is just a good approximationas you really want to align the acoustic centres of the two drivers. The top plates is as good a starting place as any. So how far back will be dependant upon your mid horn. Are you going to run a 1 inch or a two inch mid driver? The two version Heritage tweeters are good horns and the drivers seem to be fine especially with the Titanium diaphragms but you could probably improve with the B&C DE25 or DE250 or others but those are very good and are reasonable in price. A couple of guys here hace gone two way with large format mid/tweeter horns and that might be an option but it sounds like you have made your decission on the mid horn so stay with a three way. Keep up posted as to how you proceed with your project. Best regards Moray James.

[jrebman]

Moray,

Thanks again. and yes, I do want to stick with the 3-way, though if I wewere building from scratch, I'd certainly consider one of the larger coax horns. I don't mind itting something on top, but otherwise I want to stick with the basic look of the cornwalls. these are walnut and the veneer and edges are all perfect, as are the grilles.

Think I'll start looking around for a pair of k79s, though not sure how difficult that will be. Also, I plan to stick with the stock k55v mid drivers for now. Too many other projects in the pipeline and I can only fit so many speakers in this house. I also want to finish my zigmahornets (also polka dotted by Bud) and plan to build a pair of Lowther Alerions for my dx-55s this summer.

P.S. -- I sadly don't have the fonkens anymore -- but my nextdoor neighbor bought them from me, so I can give them a listen whenever I want. The only problem with them, and I mean the only one, was the 89 db sensitivity -- I really need to be in the upper 90s or better for my SET addiction :-).

[moray james]

Jim you can usually find K79's on ebay. A pair of KLF30 with dual 12 inch woofers and excellent mid horns would hit harder than a Cornwall single 15 and the cabinet gets the horns up to the right listening height. But that's another project just keep your ears open for a pair if they come up in your local. Post a request for a pair of K79's on the garage sale section I am sure Noah or someone here will have a pir for you. I have a pair of K75 which as far as I know are the same thing they are physically exactly the same use the same diaphragm. See what you can find and if you are in a pinch let me know as I would rather hang on to these at the moment but I don't really need them if that makes any sense. Good luck

[jrebman]

Moray,

Thanks again. I'll have no trouble with getting the height right, and I'm really going to consider switching horses mid-stream, though if I were starting from scratch, yes, there would be many other interesting options to pursue. My listening room is fairly small and has been nicely acoustically treated, and I was getting decent bass from 6 and 8 inch drivers, so the 15 is going to be plenty. In fact, my biggest initial concern with moving the cws to this room was that it would overload on the bass. Fortunately, it seems very good, and significantly better than the other speakers I've had in here.

When I have some more cash I'll post an ad for the tweeters or look on the bay -- thanks for the suggestion.

-- Jim