New CLSIIa owner with a few questions

Hello all! As of a few days ago, I haphazardly became the owner of a mint pair of oak CLS IIa's. I was in Spokane, WA on business and after finishing work for the day, an associate had Craigslist up on his laptop and I spotted these sitting proudly in the middle of a bunch of 'Sony XPlod subs' and '13" TV/VCR combo' type-ads.

The seller's place was just a couple of minutes off the interstate on the way to the hotel, so I went over to check them out and after an hour or so of listening and confirming they were fully operational, ended up walking out the door with them for his asking price of $1195. Normally, I research my purchases infinitely better than this one, but this just kind of happened. Which brings me here...

...and after reading the wealth of info, I must admit to one part excitement (due to their potential), and probably two or three parts trepidation (due to their somewhat long list of requirements).

Having extremely limited knowledge of ESL's beforehand, I really had no idea that the panels 'go bad' over time. As to upkeep, I just contacted the original owner and he has NEVER vacuumed the panels. Examination shows that the first 5-6 rows of grille perforations on the top and 8-9 rows on the bottom have the little "dust blob dots". What is the correct procedure for vacuuming the panels?

The thing I may have going for me is that these particular panels have basically been stored in their boxes half of their lives and used very sparingly as an attraction of sorts at parties for the other half. The seller seems like a stand-up guy and said they really have been used very little. Still, a little research would have been good knowledge to have pre-purchase.

I am more of a home-theater guy, but have always enjoyed two-channel. The plan for these upon purchase was to run them in a dedicated two-channel rig located in my home theater room; which is an under-construction bonus room above the garage that measures 21'L x 12'W with a 6'-10' peaked ceiling. I will be able to pull them 4' out from the front wall but am concerned about the width. Is this limited width going to be problematic for these speakers?

If so, I have another option as we are planning on finishing a loft area above our kitchen that would allow me to place them along a 25' wall and never have to worry about side reflections again. This project is even further down the road than finishing the theater, so back to their boxes they would go.

I knew going into it that I would be wanting some dedicated gear to run these, but I did not know just how finicky they apparently are. Wow, they seem to be amp-killers. Two channels of my lowly mid-fi 5 channel Parasound amp (200 wpc @ 4 ohms) can attest to that after a little listening session last night. I've never felt that thing get so hot...it was as if it thought it was a Class A amp or something. Any recommendations for a nice high current amp that won't break the bank?

Also, the seller (the second owner that bought them from a buddy that was a dealer) said that he is near-positive that the electronics were sent back to ML for a "$6-700 dollar upgrade" right before he purchased them in '93 -- I'm thinking this may have been for the upgrade to 'Z' status? Is there any way I can confirm/deny this by looking into the electronics box?

They are certainly shy on bass for the way that I like to listen. I will be pairing them with an infinite baffle subwoofer...I actually had 8 of the same 15" drivers that JonFo on here uses, but just sold a pair to a guy so he could make a four-driver IB. I'm leaning towards selling the remaining 6 and picking up four 18's. Infinite baffle bass seems like it will be a truly excellent match up with these full panels.

Aaron

Aaron S said:

I am more of a home-theater guy, but have always enjoyed two-channel. The plan for these upon purchase was to run them in a dedicated two-channel rig located in my home theater room; which is an under-construction bonus room above the garage that measures 21'L x 12'W with a 6'-10' peaked ceiling. I will be able to pull them 4' out from the front wall but am concerned about the width. Is this limited width going to be problematic for these speakers?

Click to expand...

Have you thought about "long wall" speaker placement? I've always wanted to try that but haven't had the right room for it.

Oh, and a forum search will show you all you need to know for vacuuming.

Oh boy ! IB with CLS will be outstanding! Give me the serial # on the panels and on the crossover boxes and I can tell you exactly when they were made and how old they are. If the panels are replacement models !

most of what I said in the other post is true!

Vacuuming is done with a good dry shop vac.

The width is a tad narrow but the CLS are good at dealing with a narrow room. You will not need any toe angle that is for sure.

The spots on the panel are normal if they are all the same size like the stator holes. If they are really gray , your prolly gonna need new ones as it usually means they are older and have seen better days. Let your ears tell you. Take a white noise test tone and check for even sounding tone at 75 db with a Rat Shack meter. They both should be with in 1 db of each other. If you have ghost dots like golf ball sized spots that appear in the right light,that is a sign of age and humidity !

If you get a tad bit of kazooing , do not be afraid to use a hair dryer to re tighten the Mylar at the sides and corners of the bass area.

Other CLS guys will help you out better than I can. But they sound like very old CLSs... and if they have never had a panel change they will almost certainly need it. I know they haven't been used much by the guy you bought them off but 200W should bring them to life.

I wish there was a magic panel tester newbies could use to tell them if a panel change is necessary... alas, there is not! Because the CLS has no woofer, you can't tell if you have excessive bass output i.e. the panel output has dropped.

CLS owners to the rescue?

Well done CAP - you beat me to it - made a cuppa whilst typing!

Aaron - don't worry - one the CLS guys sort you out THEY WILL BE AWESOME!!!

Justin

If you can't talk Chris into welding some stands for you like his Arcici copies (why make him waste all that trial and error time?) you can buy these which I use and like very much: http://www.soundanchors.com/page24.html

I'd advise against wood. Metal (especially the bracing) is far superior for holding the entire panel rigid, top to bottom.

C.A.P said:

Oh boy ! IB with CLS will be outstanding! Give me the serial # on the panels and on the crossover boxes and I can tell you exactly when they were made and how old they are. If the panels are replacement models !

Click to expand...

The panels are CS2AH630 and 631 and the electronics CEAIO13. Referencing the secret decoder sticky, it doesn't look like these things could be much older. #13 for the electronics...maybe they're borderline collectable with numbers that low.

C.A.P said:

The spots on the panel are normal if they are all the same size like the stator holes. If they are really gray , your prolly gonna need new ones as it usually means they are older and have seen better days. Let your ears tell you. Take a white noise test tone and check for even sounding tone at 75 db with a Rat Shack meter. They both should be with in 1 db of each other. If you have ghost dots like golf ball sized spots that appear in the right light,that is a sign of age and humidity! If you get a tad bit of kazooing , do not be afraid to use a hair dryer to re tighten the Mylar at the sides and corners of the bass area.

Click to expand...

They passed the dB check perfectly matched. Have not noticed any golf ball sized spots...do you really mean spots the size of golf balls? When vacuuming, can I hook up a soft bristle attachment to help dislodge the dust? I did not see anything mentioned when I searched.

The only noise (other than lush vocals) I've heard that calls attention to itself has been a very slight distortion in the upper frequencies on crescendos when pushed hard on a track or two.

They are currently hooked up in my family room that is 15'W x 26'D with a 21' ceiling. This room is directly open to a 15'W x 26'D kitchen/dining area with a 10' ceiling...no worries of the CLS' pressurizing this space. With the centers of the panels 7' apart and the seating distance at 9' (per a previous post by nsgarch that I saw), they sound quite nice.

If the panels do indeed need replacing, I am hard pressed to notice. Ignorance is bliss perhaps...

C.A.P said:

The width is a tad narrow but the CLS are good at dealing with a narrow room. You will not need any toe angle that is for sure.

Click to expand...

This is good news! After listening to them for a few hours in the fairly large 12000+ cubic feet space they are in now, I think they will do great in my 2000 cubic foot theater room. It looks like I can get them about 1.5' away from each side wall. I still cannot believe how everything just goes away when I stand up from the listening chair. Pretty crazy compared to my Tannoy Dual-Concentrics that are going into the 7.1 setup...these sound nearly the same from any point in the room. The CLS have very similar coherency though when in their sweet spot.

Here's a couple of pics of the CLS' in their temporary setup:

You came across a nice deal. The CLS seems to be hard to find speaker and most sellers don't want to deal with shipping which only adds to the challenge of obtaining a pair. The panels probably have plenty of life left in them since they were stored in the boxes for half their life. Exposure to the elements and environment is what wears on the panels the most. Keep them clean and they'll last quite some time. If you ever need panels, ML is pretty good about building replacements for the older models.

CLS advice

Vacuum once a month after disconnecting at least 8 hours from the AC.Better connect to AC only when listening.A cheap decent high current amp is the Behringer EP1500-I have one.Even has good quality pots so you do not need a preamp.
You do need to keep the CLSs at least 2 ft. from the side walls.
I would recommend using a fast sub with them.
Enjoy!

Other amps

I used a Moscode 600 for over 15 years with my CLSs.Adding Zero autoformers also helped.
The Adcom 555 was halfway decent.Even the QUAd 405 worked somehow.
I currently use an ARC VS-110-around 2.5K used.

Well , They look to be clean. The panels are ORIGINAL panels not service panels. Any panel that starts with the 700 is a replacement panel. Them are OLD ! It does not mean they are bad just old. If they are within 1 db that is GOOD! I would not worry to much about them until they start to show signs of concern. Look at the 4 corners and see if you have any wrinkling if not you should be fine ! The original CLS NEEDS a big high current amp. I also would inquire Jim at ML about a crossover tweak with a few resisters in line with the panel leads on the board. It lets the amp see a smoother easier load. The distortion you may be referring to is from the amp not being able to run a 1 ohm load at higher spl.

The difference in sound from a well rear braced stand vs. a riser type stand is amazing. As Neil said ,the riser type will get them off the ground but you still need to get that panel as rigid as you can.

Don't sweat the standing up issue. Its the CLS They sound great in the hot seat and as soon as you stand up its gone. Nothing you can do about it. Its the speaker. Its a 1 person speaker. I always said, audio is not a spectator sport! Your either in the sweet spot or not !
That is why I do not recommend the CLS for HT !

I would like to thank everyone for all of the CLS tips! :bowdown:

C.A.P said:

Them are OLD ! It does not mean they are bad just old.

Click to expand...

Yep, they are old. I looked for wrinkling and see no signs. They are in remarkably good condition for their age...kind of reminds me of my aunt's '58 Corvette convertible w/ a fuelie 283 and 44,000 original unrestored miles...not a bad old thing to own!

The distortion you may be referring to is from the amp not being able to run a 1 ohm load at higher spl.

Click to expand...

This is exactly what I was thinking. It was only on a few of the transients at high volume. I also admit to not having any banana plugs here or thin enough cable to fit into the tiny little hole in the binding posts, so I used my regular 12 gauge wire jammed into the posts' end in the meantime. Probably a little resistance due to the weak connection.

The difference in sound from a well rear braced stand vs. a riser type stand is amazing. As Neil said ,the riser type will get them off the ground but you still need to get that panel as rigid as you can.

Click to expand...

I am surprised by the amount of flex in the panel's connection to the electronic box. The whole panel seems to move a bit too easily...can't be too good for sonics.

Don't sweat the standing up issue. Its the CLS They sound great in the hot seat and as soon as you stand up its gone. Nothing you can do about it. Its the speaker. Its a 1 person speaker. I always said, audio is not a spectator sport! Your either in the sweet spot or not !
That is why I do not recommend the CLS for HT !

Click to expand...

My sentiments as well. What could be the CLS' biggest weakness is also it's biggest strength I think. My listening room is away from the rest of the house anyway, and there is not a lot of wandering around I'll be doing in the 21x12 space.

I'm considering re-working the knee walls in the room by adding more dormers to widen the room to 17'. There is currently one dormer in the room that is 7' wide by 30" deep that I was going to wall off and use as a closet to make the room symmetrical. Widening the room would be great for the overall sonic presentation, but I'm not sure I want to spend what it will take to do it.

raanan said:

A cheap decent high current amp is the Behringer EP1500-I have one.

Click to expand...

Cheap is right on those Behringer's. A knockoff of a decent QSC design using lesser quality parts. They make decent sub amps if not pushed too hard I suppose. I actually have 5 QSC DCA 1622 amps (300 wpc @ 8 ohms, 500 wpc @ 4 ohms, 700 wpc @ 2 ohms) and was thinking of trying one out, but it seems like it may be sacrilege to run a pro amp on the CLS.

I would recommend using a fast sub with them.

Click to expand...

IB bass is about as 'fast' as it gets. If the motor can control the cone then 'fast' it will be.

Another piece of advice

Bypassing the speaker terminals is a must for really good sound-the difference is unbelieveable.Listed in the tweaks section.
I disconnected the connections from the board to the speaker binding posts,and then connected my speaker cables directly via a miniature clamp for each connection.The binding posts on the CLSs introduce deterioration and distortion of the sound.
I would definitely try a higher powered tube amp(100 and above),and experiment with Zero autoformers.Using my ARC VS110-the autoformers do not help.Using the Moscode 600-definite improvement.
Enjoy.

Aaron S said:

I am surprised by the amount of flex in the panel's connection to the electronic box. The whole panel seems to move a bit too easily...can't be too good for sonics.

Click to expand...

MiTT did an analysis of the sway issue we did discussed at length here...

"I've actually modeled the speaker in SolidWorks and run it through COSMOS to measure what sort of deflection I might actually see near the top assuming a rigid anchor near the bottom. Even with a force of 120lbs applied at the top the frame will only deflect about .033"."

I would think most here would agree the bracing helps with resonance control more than actual swaying of the panels.

Most here have found raising the panels up so the middle spar is at ear height in your seating position is also a benefit.

Also play with tilt of your panel as this can also change the sound to your liking - some like the panel absolutely vertical and some like it tilted back some. Toe-in amounts also is something to adjust along with tilt.

It is amazing what you can do in the way of sound with the CLS with all these little tweaks.

DTB300 said:

MiTT did an analysis of the sway issue we did discussed at length here...

"I've actually modeled the speaker in SolidWorks and run it through COSMOS to measure what sort of deflection I might actually see near the top assuming a rigid anchor near the bottom. Even with a force of 120lbs applied at the top the frame will only deflect about .033"."

I would think most here would agree the bracing helps with resonance control more than actual swaying of the panels.

Click to expand...

Thanks for the info DTB.

I can't wait to be able to get these into their permanent home and start playing with them...but I'm going to have to as I am leaving Saturday for a 2-week vacation, and I still haven't started on finishing the room yet.

raanan said:

I would definitely try a higher powered tube amp(100 and above),and experiment with Zero autoformers.Using my ARC VS110-the autoformers do not help.Using the Moscode 600-definite improvement.
Enjoy.

Click to expand...

I have a feeling I would really like them on a nice fat tube amp...but I'm not sure I want to deal with the 'high maintenance' that a big power tube amp might require. I have a 38 wpc Onix (Melody) SP3 right now, but this obviously wouldn't cut it driving the CLS.

Aaron S said:

I have a feeling I would really like them on a nice fat tube amp...but I'm not sure I want to deal with the 'high maintenance' that a big power tube amp might require.

Click to expand...

If you buy a tube power amp from a reliable manufacturer like AR, BAT etc chances are you really WON'T have any issues beyond a tube change - no far off changing a light bulb, really. Don't be scared - tube amps, for the most part, really don't bite as hard as most think they do!