High Efficiency Speaker Asylum

Need speakers that can rock with just one watt? You found da place.

Return to High Efficiency Speaker Asylum

Message Sort: Post Order or Asylum Reverse Threaded

Karlson with University 312

98.122.65.234
Posted on February 9, 2014 at 14:03:17
roof16
Audiophile

Posts: 8
Location: South Carolina
Joined: February 9, 2014



Ok guys picked up a nice pair of K cabinets with mint University 312 diffaxials. Before I got them I did quite a bit of research and found out the K's can be quite polarizing...even saw the the Klipsch 312/Karlson waveform which was surprising. Got them anyway because they have a lot of fans too. Hooked them up to my Sherwood S5500 and I have to say I was not impressed. Thought it might be the amp so since then I have tried three more from Pioneer 1080 to low power Sherwood ss..still sounds sort of muddy. Anybody got any suggestions? Freddy?

 

Hide full thread outline!
    ...
RE: Karlson with University 312, posted on February 9, 2014 at 14:55:07
freddyi
Audiophile

Posts: 3866
Joined: December 6, 2001
 the motors on some of their woofers are not very strong - I don't think I've owned the 312 if its twice the weight of some of their other 12cx

- you might like a 312 better in a large box or on an open baffle - the grill cloth on some vintage cabinets can eat high frequencies - do the tweeters seem loud and their level controls responsive? - it might not hurt to replace the caps in their crossovers - I'd like to see a picture of the rear insides with back removed. If you bum out too much then I'll offer to buy your Ks. (cabinets only)

here's a decent coax for a K12 - I've even heard weak fullrange sound pretty good in K12 on vocals


Karlson Evangelist

 

RE: Karlson with University 312, posted on February 10, 2014 at 04:02:09
roof16
Audiophile

Posts: 8
Location: South Carolina
Joined: February 9, 2014
 I'll crack 'em open today and take some pics...tweeters seem good and presence control works fine. In fact on the high end they are pretty good...the low end just doesn't sound as clear. PM me with your email if that would be better. BTW thanks for all the great info you have contributed on the internet...between the Karlson site and your posts I've gotten quite an education.

 

RE: Karlson with University 312, posted on February 10, 2014 at 08:32:50
roof16
Audiophile

Posts: 8
Location: South Carolina
Joined: February 9, 2014






Hey Freddyi...here are pictures of inside of cabinet + University 200...thanks

 

RE: Karlson with University 312, posted on February 10, 2014 at 11:49:34
Paul Scearce
Audiophile

Posts: 471
Joined: March 1, 2002
 I think the type of Karlson enclosures you have normally has a series of 1/8" slits in the upper baffle board above the shelf. These act like an aperiodic vent to lower the system Q. Your copies seem to have the back volume behind the drivers completely sealed. I would expect the small sealed volume behind the high Qts University drivers to boom a bit. Try them at low levels with the backs removed and see if that improves the sound.

 

RE: Karlson with University 312, posted on February 10, 2014 at 14:01:54
roof16
Audiophile

Posts: 8
Location: South Carolina
Joined: February 9, 2014
 I'll give it a try...I noticed the same thing no ports at all

 

RE: Karlson with University 312, posted on February 11, 2014 at 02:03:38
freddyi
Audiophile

Posts: 3866
Joined: December 6, 2001
 you can try some polyfil in the rear chambers - - assuming those are factory then they're a model which was sold I believe with instructions to optionally vent. I've seen one unvented pair on Ebay about 5 or six years ago. If my health improves and you don't like them then I'd like to perhaps adopt them.

I'd like to have the outside dimensions of your cabinets plus the distance from the floor of the cabinet to the bottom of the rear shelf.

with the cabinet sealed, I'd imagine system resonance is quite high. The slits tune small signal around 62Hz or so. They also will distort on sine. Venting at this point would take some care and thought.

below is a set of factory K12 which housed Tannoy Red - you can see the location of the Kimsul damping pads.

here's part of what came with the unvented K12 kit

Karlson Evangelist

 

RE: Karlson with University 312, posted on February 11, 2014 at 07:33:57
roof16
Audiophile

Posts: 8
Location: South Carolina
Joined: February 9, 2014









Thanks Freddi...here are the dimensions you asked about: H-23.5" W-16.75" D-14.25"...bottom of inside cabinet to shelf is 12.25". BTW while I had the backs off I decided to take a listen...much better overall sound bass was tighter and highs were much clearer. So it is apparent to me that to get the best sound I've got to figure out a way to port them. But I don't want to spoil what seems to be an original version of the K-12...was thinking about a port in the back. I wouldn't cut the original back, but could cut a piece to use for test. What do you think? I don't want to indiscriminately start cutting up a piece of audio history. They really are in nice shape as you can see from a couple of additional pictures attached.

 

RE: Karlson with University 312, posted on February 11, 2014 at 08:06:31
Hornlover
Manufacturer

Posts: 2529
Joined: March 8, 2002
 I really don't think the Karlson enclosure is the best for that driver. The University is similar to a lot of the EV drivers from those days, with a fairly high Q. I think an open baffle may be the best solution (you wont have much low end), or a fairly large bass reflex.

 

RE: Karlson with University 312, posted on February 11, 2014 at 10:42:45
freddyi
Audiophile

Posts: 3866
Joined: December 6, 2001
 if the 312 is like a 6201 then its Qts is too high for best sound in a Karlson with a 1.3 cubic foot rear chamber. Karlson's are coupled cavity slot loaded type and when vented, usually series vented - a new ported back panel would make these parallel vented - not sure of the result but something to try on one cabinet. Weak motor coax and fullrange will probably sound better on a simple flat baffle - One can experiment with cardboard for open baffle wings to hear effects.

being careful, those Karlson port panels could be be cut for vents like my set of K12, those Tannoy K12 with distributed hole vent, or a singular rectangular vent (last works but has not been seen on a factory K12) - that could be useful for some speakers - maybe your 312 I've run K12 sealed as a woofer with sealed box 12" such as a MCM dual voice coil woofer used by the late Marshall Leech. In that case qtc is favorable even without stuffing.

these are cool cabinets and appear factory.

one very rough rule for rear chamber volume in a K is Vbr = (Qts*fs*Vas)/50 (where 50 in this case is Fc)
Karlson Evangelist

 

RE: Karlson with University 312, posted on February 11, 2014 at 11:14:37
freddyi
Audiophile

Posts: 3866
Joined: December 6, 2001
 re: 23 1/2" height - - if so then 1" shorter than most K12

re: venting the back panel - I'd give that a try - use whatever scrap to make a new back -- - those must be very rare and as a guess from the mid 1960's. We know from the Tannoy factory-loaded example that 1 12-hole array worked - but since the late Gregg Baker's K-forum is gone, I'm not sure of the hole spacing nor diameter - - could be 3/4" - -could be 1" (?)

the K12 below with 4-slot vents is mine

A pair seen from a Lafayette Radio stash


Like yours, I believe and factory loaded with Tannoy Red - imo, you would have to hold a board up against the port panel when drilling these holes to prevent damage to that particleboard panel.

Kenpeter did a nice 3D rendering of your style K12 based on some dims gathered from a pamphlet illustration.

Greg B's overlay of dimensions over the pamphlet drawing

Mine

I hope sometime to find someone who can make a pair like yours for me.

don't forget to try an open baffle - - that may be better and more practical for your 312 than anything else
Karlson Evangelist

 

RE: Karlson with University 312, posted on February 11, 2014 at 12:57:02
Greg B
Audiophile

Posts: 983
Location: Los Angeles, California
Joined: January 21, 2002
 Yeah, I also think the problem is the K12 is simply too small. It might actually be quite nice in the larger K15.

You can get a very rough idea of the response by modelling it as a BP6, using about 150Hz for the front chamber tuning. This will not give you an accurate predicted FR - real life measurements will always be better, but huge peaks etc should give you a general idea if the volume and tuning is totally wrong.

I played around with the original 1958 slit vent K12 for a while. The slit vents do kinda/sorta make them work as a universal enclosure, and can deal with higher Q and sound OK, but it isn't really optimal IMO.

Personally I'd make an adapter plate and put some 8" full rangers in there.

 

RE: Karlson with University 312, posted on February 11, 2014 at 16:25:38
freddyi
Audiophile

Posts: 3866
Joined: December 6, 2001
 he could also obtain venting like the R-J by spacing the adapter plate from the nominal 10 -3/4" cutout. For that matter, he could try spacing the 312 coax maybe a 1/4" or so from the cutout with washers being careful not to apply much torque to the mounting screws as the frame might warp a bit.
Karlson Evangelist

 

RE: Karlson with University 312, posted on February 12, 2014 at 04:29:56
roof16
Audiophile

Posts: 8
Location: South Carolina
Joined: February 9, 2014
 I must have spaced out when typing...cabinet height it is actually 24.5"...they also have built-in 1.5" feet that raises height from floor to 26". So I guess they are standard K-12 dimensions after all. Little nervous about trying to drill inside the cabinet...at a minimum the grill cloth would be ruined. I don't see how to remove it anyway...it appears to be built into cabinet...from the plans look likes it was included in kit and therefore original or somebody did a magic job replacing it. Wouldn't be in end of the world, but I'm not sure there are many out there in basically oem condition...hate to ruin them in process. I'll let you know how the venting mod on the back turns out...when I get plywood I'll make sure I get enough to experiment with OB too. Should I decide to part with them...I'll give you first crack if you are interested. Once again thanks for all the info...it is always good to learn something new.

 

RE: Karlson with University 312, posted on February 24, 2014 at 07:05:47
roof16
Audiophile

Posts: 8
Location: South Carolina
Joined: February 9, 2014



Thought you guys might be interested in my latest mod to Karlson/312 combo to improve sound. After I listened to them with the backs off and they sounded better, I decided to make a new ported back. At someone's suggestion, I decided to make it an aperiodic design. I'm listening to them now with the mod I crafted from scrap plywood...I didn't want to ruin the original backs. The sound is much, much improved...clearer with just as much low end. I can't wait to play around with tuning them by trying different amounts of restriction in the port. Anyway, I made the port exactly the size of furnace damper filters. So tuning is easy by just removing/adding layers until the desired sound is achieved. Also, added 5-way posts and replaced original tone control. Easy project with good results...

 

RE: Karlson with University 312, posted on February 26, 2014 at 00:41:56
freddyi
Audiophile

Posts: 3866
Joined: December 6, 2001
 that's way cool and a first! perhaps it should be tried with some other K/speaker combinations
Karlson Evangelist

 

Thanks Freddyi, posted on February 26, 2014 at 03:22:54
roof16
Audiophile

Posts: 8
Location: South Carolina
Joined: February 9, 2014
 Thanks...lot of fun to play around with different combos to see how it affects sound. I was wondering if you had heard of anyone trying this.

 

Page processed in 0.034 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]