stacking 17's

[Guest fourwheels0]

has anyone stacked 17's like people do with the large advents. just wondering what peoples thoughts are on this.

[Guest rhollingsworth]

has anyone stacked 17's like people do with the large advents. just wondering what peoples thoughts are on this.

Hello.

I bought a pair of 17s new in 1971 and have taken good care of them; they look and sound fine.

Recently I bought another pair at a resale shop for $16. The turkey who had owned them wasn't very nice to them. The finish is not too good and has some hefty chunks gone in places. He/she even had applied some adhesive-backed felt or something to the bottoms, so as not to mar their valuable floor, I guess. The grill cloths are dingy. Looking at the drivers, I see they are sealed into the mounting holes with this goop that KLH reportedly used in the early 60's, and where it can be touched, it disintegrates.

The surrounds on the woofers... can't tell yet if they need restoration... they probably do.

I thought, what the heck, since the felt is already there, I'll stack them on top of my other ones.

They are wired parallel. Power is coming from a Panasonic Ramsa WP1200, and the preamp is my old Dyna PAT-4.

I've taken care so far not to push the levels too high.

The sound? All I can say is, it is spectacular and wonderful.

Presence, clarity and soundstage like I have never heard.

I have no idea why; I'm just enjoying it.

RH

[soundminded]

In general, the cloth surrounds on KLH woofers do not deteriorate with time the way foam surrounds on many AR and other woofers did. Unless they were physically damaged, there is usually no reason to replace them. However, the cloth may have become pourous. This would manifest itself in reduced bass. Compare the new and old ones but even the old ones may have become pourous as well. We've discussed at length many different concoctions that can be applied so check the archives. Be careful, applying anything which hardens will damage the speaker badly. If the "goop" forming the seal between the speaker frame and box has cured and you don't want to remove the driver to scrape it away and replace it with more goop or foam tape sold at parts express, you can do what I did to restore the air tightness of my Bose 901 drivers where the goop actually hardened and cracked. Apply some clear GE silicone caulking around the joint between the metal speaker basked and the wood and around the screw heads. Be careful not to get any on the cone or suspension. It take about 24 hours to cure and can be removed at a later time. It's easy to work too, you can use your fingers in fact. If a tweeter fails, it is almost invariably a bad capacitor. It's the same as the tweeter used in the model 6 among others. I had to replace one and found it easy just by removing the tweeter and pulling the wires through the opening. the Capacitor was wired in line and accessible. Good luck.

[JKent]

hey "cousin"

Soundminded just reminded me--the caps in the 17s are HORRIBLE. They are the infamous black and red Callins caps and they are most certainly dried up or worse (see attached photo). The 17s are sweet speakers. I'd recommend replacing the caps on all 4 speakers. You'll need two 2uF and one 8uF per box.

Kent

[Guest rhollingsworth]

Thanks to both of you, soundminded and jkent, for the guidance and the photo (looks like a bad cap to me!).

RH

[Zilch]

has anyone stacked 17's like people do with the large advents. just wondering what peoples thoughts are on this.

It's axiomatic: multiple sources playing the same program material in a listening space WILL interfere with each other in a complex manner which varies according to the distance differential(s) to the listener. See "Demonstration of Principle" here:

http://www.jblpro.com/catalog/support/getf...1&doctype=3

I've posted the KLH Seventeen crossover schematic, transfer functions, and measured attenuation response here:

http://www.audiokarma.org/forums/showpost....p;postcount=182

The rest of that thread is not for the squeamish restorationist, but there's information regarding "redoping" KLH-17 woofer surrounds in the early pages there. Bottom line: we need to rethink gratuitous intervention for its own sake; determine first whether it is actually required, and some, if not most, of the substances commonly recommended for this purpose are inappropriate.

For those who just need the crossover schematic, click below. S1 center position is "No connection."

[dingus]

have you tried inverting the top speakers? it puts the drivers in a quasi-d’Appolito array that you might find more pleasing. i know this is the case with Large Advents, at least imo.

[Zilch]

have you tried inverting the top speakers? it puts the drivers in a quasi-d’Appolito array that you might find more pleasing. i know this is the case with Large Advents, at least imo.

Not askin' me, I trust, but yeah, done that:

http://www.audiokarma.org/forums/showthrea...882#post1913882

[boreas]

Not askin' me, I trust, but yeah, done that:

http://www.audiokarma.org/forums/showthrea...882#post1913882

Wow, after reading the AK thread on the Seventeens I'm beginning to think I made a mistake! I just picked up a pair of them at my local Goodwill boneyard, their "As-Is Store", where they put stuff not deemed good enough for the regular stores. The price, you ask? A buck apiece. Unbelievable!

Cosmetically there a bit challenged but not much. The wood is VERY dry but that's easy to address. One speaker will come up fine with a little sanding and oiling. The other has some veneer loss at one back corner and a cluster of small but deep gouges on one side. (Time to experiment with tinted epoxy.) The outer grille cloth is shot (cat?) but the inner layer of black cambric is reusable. One of the boards will need to be re-cut as it's broken. One KLH emblem is missing. All in all, the cosmetics will be pretty simple to address.

The woofers look just fine. I'll probably re-dope them but I'll wait and see on that. The caps are intact. None have grenaded yet, Kent, but I'll probably replace them. (They're black with "N.P." and then "+ SUF-50V +" printed on them in white.) Again, I'll wait to hear what they sound like before deciding.

The tweeters look good as well but the aluminum screen covering one of them had been dented in to the point of contact with the tweeter cone. There's no doubt that there would have been quite a buzz from that so I carefully removed the screen and straightened it. It's ready to go back on but I wanted to check with you all first to see whether there's a recommended adhesive for reaffixing the screen. The adhesive used by KLH is slightly soft and resilient when dry, like contact cement but unlike epoxy. I'm thinking that's important for isolating the screen from the actual speaker but I wanted to ask the experts.

Any advice or information will be greatly appreciated!

TIA, John

[boreas]

have you tried inverting the top speakers? it puts the drivers in a quasi-d’Appolito array that you might find more pleasing. i know this is the case with Large Advents, at least imo.

My only experience with stacking speakers was with Model Thirties. I stacked them "woofers down" all the way around and hooked them up top pair to the "A" speaker terminals and bottom pair to the "B" terminals. I thought they sounded really good.

I built a little divider out of 1/2" cabinet grade plywood, the same dimensions as the width & depth of the speakers plus 1/16", with a lip around the perimeter. This served to locate one speaker securely atop the other.

Seventeens and Thirties are the same size, basically the same speaker. The cabinets are not very deep, so the stacks were a bit "tippy", especially on carpet, so I made some platforms to go under the bottom speakers to widen and deepen their "footprint". This made them much more stable. The platforms also created a little air space between the speakers and the floor.

John

[Zilch]

Wow, after reading the AK thread on the Seventeens I'm beginning to think I made a mistake!

This one?

http://www.audiokarma.org/forums/showthread.php?t=205379

O.K., I'll stop now, before I get banned as "subversive."

It's a hobby, and what I do is well outside the mainstream here; I just popped in to post the schematic, really....

[boreas]

The woofers look just fine. I'll probably re-dope them but I'll wait and see on that. The caps are intact. None have grenaded yet, Kent, but I'll probably replace them. (They're black with "N.P." and then "+ SUF-50V +" printed on them in white.) Again, I'll wait to hear what they sound like before deciding.

Well, I decided to hook them up "As-Is" to see what they were like. I connected them to my Pioneer SA-8500 II & Rotel RCD-855 in place of the ADS L780-2 speakers I've been auditioning. They're absolutely great. I'm not sure whether I'll redope or recap them just yet - if ever.

There's one thought I did have, however, and I wanted to run it by the forum. I've heard it said that the Model Seventeen gives up a little on the treble. Like a lot of KLH tweeters, these have perforated aluminum screens to protect the cones. These *have* to reflect some of the highs right back at the speaker, right? This would cut down on the highs, right?

As I mentioned in an earlier post, I've got one of these screens off for repair and it occurred to me that, rather than replacing it, I might just go ahead and remove the other one and thus enhance the HF performance of the speakers.

It also occurs to me that I might be completely out to lunch on this. That which may seem logical isn't always correct so expert advice will be much appreciated.

Thanks,

John

[Zilch]

There's one thought I did have, however, and I wanted to run it by the forum. I've heard it said that the Model Seventeen gives up a little on the treble. Like a lot of KLH tweeters, these have perforated aluminum screens to protect the cones. These *have* to reflect some of the highs right back at the speaker, right? This would cut down on the highs, right?

As I mentioned in an earlier post, I've got one of these screens off for repair and it occurred to me that, rather than replacing it, I might just go ahead and remove the other one and thus enhance the HF performance of the speakers.

It also occurs to me that I might be completely out to lunch on this. That which may seem logical isn't always correct so expert advice will be much appreciated.

I expect the screens are functional, and intentional, perhaps to smooth the response. I have posted the HF response, and linked to it @ #6, above. If that's how they actually perform, generally, I doubt you're going to achieve more extended VHF without the screen, and it's already, well, "excessive" on axis. Off-axis response is shown earlier in that thread:

http://www.audiokarma.org/forums/showthrea...845#post2229845

At this point, I have only one KLH-17 tweeter, and it is not mine; otherwise I'd measure the difference for you. That situation may change in a week or so, in which case, I'll post my findings regarding this issue.

[boreas]

This one?

http://www.audiokarma.org/forums/showthread.php?t=205379

No, it was another one Much worse!

[boreas]

At this point, I have only one KLH-17 tweeter, and it is not mine; otherwise I'd measure the difference for you. That situation may change in a week or so, in which case, I'll post my findings regarding this issue.

Great! Thanks. Also thanks for the reminder of your earlier post on VHF frequency response. I'll go back & look at it. Might even understand it. Or parts or it. Or not.

[Zilch]

Great! Thanks. Also thanks for the reminder of your earlier post on VHF frequency response. I'll go back & look at it. Might even understand it. Or parts or it. Or not.

If the intent of the screen is to improve dispersion via diffraction, it's not happening above 10 kHz, apparently....

[boreas]

If the intent of the screen is to improve dispersion via diffraction, it's not happening above 10 kHz, apparently....

I dunno, I just thought it was there to protect the tweeter cone. The cone's very shallow and essentially flush with the face of the cabinet pretty vulnerable, even with grilles in place.

John

[boreas]

Seventeens and Thirties are the same size, basically the same speaker.

John

Well, that's what I get for relying on my memory. They're NOT the same size. Close but not the same. The Thirties are shorter, shallower and wider than the Seventeens but only fractionally. The cabinet volume is probably all but identical and they share speaker sizes in common. Placement of the speakers is a little different though. The tweeters are lower in the Seventeens, making them closer to the woofers.

Model Seventeen

23.125 H x 11.875 W x 8.875 D (including "lip")

Model Thirty

22.625 H x 12.75 W x 7.875 D

It should be noted that the front panel of the Thirties is nearly flush, being recessed only about 0.25", while the Seventeens have quite a bit of set-back to the front panel, 1" in fact. That would make the interior cabinet depth of the two models nearly identical.