Speakerlab S7s Rebuild and Modding (Ribbon Tweeter Model)

Howdy. This is my first post here, and first off thanks to all of you for the many fine hours that I've spent here reading and learning.

I have a pair of 1983 Speakerlab Super 7s that I've waited many years to start rebuilding. And now is finally the time to start. I will have many questions to ask, but first it might be nice to feed the community.

Since it seems that info on these old beasts is hard to come by I thought that I would post as much info as I can, dimensions etc, in case it's usefull for anyone that might want to try to homebrew a set. I still have my original owners manual and warranty card, and have/will take some shots of all of it, and have drawn a schematic of the crossover to share if anyone is interested.

As soon as I have re-sized some pics and done some scans I will be able to start sharing.

Cheers,
Bratwurst7s

edit 20-March-2021: Now that this thread has reached over 400 posts nerdorama suggested that I add some kind of index. So here it is. Very simple, just a list of subject headers with post numbers following. Not perfect but hopefully helpful.

Cabinets, cab seals, cab finishing and damping material:
2, 3, 15, 42, 46, 50, 54, 55, 56, 72, 80, 81, 82, 83, 88, 89, 141, 155, 189, 190, 199, 295, 297, 299, 322, 323, 328, 448, 449

Test programs, test results and simulations:
216, 217, 218, 219, 220, 231, 233, 234, 235, 236, 242, 246, 250, 251, 254, 255, 256, 257, 258, 259, 260, 301, 308, 384, 387, 388, 390, 394, 430, 443

Original crossovers and recapping:
8, 34, 69, 70, 187, 199

Tweeters:
67, 68, 113, 114, 143, 160, 381

Midrange drivers:
6, 8, 13, 28, 121, 143, 157, 158, 261, 262, 319, 320, 321, 381

Woofers: 6, 13, 57, 60, 167, 174, 176, 190, 205, 207, 209, 211, 254, 258, 259, 323, 351, 352, 353, 361, 374, 377

External crossover enclosure:
229, 230, 275, 276, 277, 281, 282, 290, 295, 297, 299

New external crossover, general info:
(1st version): 260, 269, 271, 283, 285, 293, 301, 308
(2nd version): 382, 384, 386, 387, 388, 389, 395

New external crossover, tweeter section:
(1st version): 290, 301
(2nd version): 388, 389, 400, 402, 404, 415, 421
(3rd version): 454

New external crossover, midrange section:
(1st Version): 292, 293, 302, 308, 309, 313, 314
(2nd Version): 384, 386, 387, 389, 390, 394, 395, 397, 414, 415, 421, 442, 443, 444

New external crossover, woofer section:
(1st version): 287
(2nd version): 445, 446, 447, 449, 500

Capacitors: 8, 15, 70, 230, 269, 271, 283, 285, 287, 290, 293, 389, 390, 394, 400, 402, 404, 405, 414, 415, 437

Inductors: 230, 269, 285, 287, 290, 293, 308, 425, 426, 427, 431, 437, 438, 445, 447, 450

Resistors: 15, 287, 293, 301, 302, 387, 421, 425, 437, 442, 444, 450

Wiring, internal and external: 151, 154, 291, 395

Stands, bases, spikes, granite: 90, 166, 168, 182, 212, 391, 392, 393, 420, 421, 422

Howdy,

I bought these speakers at the Tacoma store on Bridgeport Way in March of '83 for $818.00 as kits, with finished cabinets, but saved $50 each by putting them together myself. Specs from the manual as follows...

Speakerlab SS7
Crossover freq = 350hz & 3.8khz
4 ohm
200 watts max rms, 10 watts min.
105 lbs
H = 38 1/2"
W = 16"
D = 13"

They have/had the T215s leaf tweeter, M654P polycone midrange, and W1008P (polycone) and W1208R woofers.

The stated dimensions in the manual differ from what I just measured by a bit on my cabinets, namely the depth being 14 1/32" (355mm).

The walls are oak veneer on 3/4" particleboard.

The inside measurements are (I measured them in mm OK?) w=368mm, h=940mm, d=319mm, giving a basic volume of 110.348 liters.

There are 2 side braces measuring h=770mm, b=39mm, d=18mm, mounted about 170mm from the back wall and centered in height. There is a cross brace measuring 368x50x18mm. The braces were factory installed and are particleboard. The cross brace is positioned with it's bottom side 325mm/12.5" above the inside bottom of the cabinet, just low enough to provide clearance above for the W1008P magnet and low enough for a brace between the front baffle and back wall to be mounted between the woofers.

The midrange enclosure I had to glue in myself, and measures 191x191x319 on the outside and 152x152x319mm on the inside, giving an inside volume of about 7.47 liters.

So that leaves an inside volume of about 97.3 liters for the woofers. For some reason the insides of the side walls and top are also laminated with oak veneer, but not the back or bottom.

When I have a little more time I'll measure the front baffle.

I had to cut the openings in the back of the cabinets for the speaker wire connectors myself, and if you tied me down and forced me to tell the truth I didn't do a very clean job of it back then. There might have been alcohol involved. I don't remember that night very well actually, it was a long time ago. That's my story and I'm sticking to it.

Cheers,
Bratwurst7s

edited 26-09-13 - added crossbrace info

Hello,

I sketched out plans for the front baffle and am attaching them here, warts and all. I started out providing measurements in both inch and metric, but by the second drawing I kinda gave up and just used metric. I tried to be as accurate as possible with the tools at hand, but they are by no means perfect. To keep under the attachment limits the scans are fairly low res. If they are not readable for anyone please let me know and I'll try to clean them up. The front baffle thickness measures 3/4" (0.781").

A couple of notes...
The high/mid baffle plates were not cut extremely accurately at the factory, but I believe my measurements should be reasonably usefull averages of what is there. Not shown on my drawing is that the outside corners have been radiused. I used the highly technical method of measuring them of going over to my toolbox and selecting sockets that I held over the corners until I found what seemed about right. That ended up being about a 19mm radius on the upper corners and about 25mm on the bottom corners, so this is Very approximate. The tweeter sits on a step routed into the baffle.

The tweeters have their connectors on the lower sides, so there are radius’s cut out of the lower end of the cutout on the main baffle at about 135° and 225°, adding lobes to the cutout of about 5mm for clearance for the contacts. My measurements are Very Approximate!



I will post the crossover plan next.

! I just realized that I made a mistake with the measurements that I posted for the front baffle panel. The measurements that I wrote on my drawing give the width of the entire cabinet and the height positions are relative to the entire cabinet height. But the baffle panel a is of course set into/onto a lip routed from the cabinet walls/roof/floor. The actual width and height of the baffle itself is approx. 388 x 958mm or 15 5/16" x 37 13/16".

After joining the forum last weekend I now notice that there is already a member here named "SpeakerlabFan". It's not my intent to step on anyones' toes, so I have no problem changing my handle if it is a problem for anyone.

Cheers
Bratwurst7s

edited 26-09-13 - added front baffle thickness
edited 01-12-13 - dumb mistake! The tweeter/midrange baffle radiuses mentioned above are wrong! I measured using a diameter. A radius is half of a dia, so the radiuses should be 3/8" (9.5mm) and 1/2" (12.7mm).

Howdy & welcome! Nice speakers well worthy of a remake if needed- look nice in your pic. though. I have a pair of the 7WA - love them- keepers!

I am a bit confused. I had a pair of SpeakerLab Super 7 and although I don't have them anymore, I still have the 2 midrange. I built mine from scratch from the catalog and what I remember is the midrage and tweeter are horns. With a 12" and 10" woofer.
I used a 6X9 mid and Realistis Super Tweeter.

Would love to find or build another pair

Hi 81,

Yes, they're worth saving. I recently picked up a pair of JBL TLX-70's from a friend for €50, so I at least have _something_ for the living room for now.

Time has had it's way with my 7s tho. The foam surrounds on the 6.5 and 10"ers went south back in '97 or so, and I had moved to Germany at that time and had no idea where to send them for new surrounds. So I ordered "replacement" drivers from Speakerlab in '98-'99 or so. Unfortunately what they sent me were in no way actual replacements. The 6.5"ers are a pair of Goldwood GW-6024, and I have no idea what the 10"ers are. They are marked W1058P but look nothing like the originals.

The speakers are now very weak in the midrange, and since then the rubber surrounds on the 12"ers have gone bad. I sent the 12"ers to an outfit up north last week for repair, and am now trying to select suitable mids and 10".

Cheers,
Bratwurst7s

Hi jjp 735i,

Starting in '81 they dropped the horns and started using the tweeters from the S50's and mids from the Delta-1 Hybrid Type-5.

Cheers,
Bratwurst7s

OK. The crossovers. When I removed them one of the inductors for the woofers had fallen off the board and was hanging down, other than that they look ok. There were a couple of mysteries though. The inductors are not marked and I wasn't sure what value the 2 yellow caps for the tweeter had.

I was able to borrow a LCR meter from work, and desoldered the inductors and those 2 caps. The caps are 2 microFarad, and the inductors measured out to 0.31 mH/0.45 ohm, 2.6 mH/1.0 ohm, and 3.4mH/0.9 ohm for the high, mid and low respectively. The high and low inductors have 20awg (0.032"/0.81mm) wire, and the mid is 17 awg (0.045"/1.15mm). The leads to the speakers are as follows - yellow = tweeter, red = mid, blue/green = 10", and blue = 12"



I have to say up front that my electronics knowhow if somewhat entry level. I was able to map out the xover and make a schematic, but I can't say that I understand it completely. The photo of the crossover should be clear enough for anyone to check my work, so if anyone sees any mistakes that I might have made please sing out.

If I'm looking at it correctly then the low end is a 2nd order, and parallel to the mid/high network? And the high is in series with the mid, both also being 2nd order?

And it looks like the mid has 2 ohms of padding, but there is another 2 ohms on the far side of the 33 &47 micro caps that would affect both the mid and high?

This is important for me to understand because I no longer have the M654P mids, which I think had an spl of around 94, and the replacements that I'm looking at buying are 91.5. (Wavecor WF168WA01) and wouldn't need as much padding? And the cheapo Goldwood GW-6024 mids that I have now only have an spl of 89, hence the weak midrange that I'm now experiencing.

That's it for now,
Cheers,
Bratwurst7s

edited 27-09-13 - added inductor and wire info

edit 07- 09 14 - !! Warning. I made a mistake here. The tweeters are not in series with the midrange! All 3 sections are in parallel. Please see post 232.
http://www.audiokarma.org/forums/showpost.php?p=8102718&postcount=232

edit 14-09-14 - Corrected schematic uploaded & incorrect schematic deleted.

I loved my 7WA SpeakerLabs. I wish I had never give them away. I'm pissed thinking about it. I just heard them yesterday and it still kinda bothers me but I can hear them anytime I wish.
Good luck with the rebuild. It is nice that you could put EV horns in there and still be a factory unit. Love those SpeakerLabs, just wish I could hear some more. The 7's are the only units I ever heard.

Thanks DaWoofer,

Finding good midranges is really the hardest part I think. Something with a high enough spl, and that can spann 350hz to 3.8khz. The best ones that I've found so far have a recommended highcross of 3khz. Something will work eventually.

I'm kinda wishing now that I had bought the S50 instead of the S7s. When I was in the Air Force my roommate had a pair of the S50's and they were a great speaker. But I was dead set on the 7 and bought them. They've been a lot of fun, but I think that with the kind of listening that I do now that I'm older and living in an apartment the S50's would be better. But whatever. I can hardly wait to get these things back into good condition and really piss off the neighbors.

Cheers,
Bratwurst7s

jjp735i said:

I am a bit confused. I had a pair of SpeakerLab Super 7 and although I don't have them anymore, I still have the 2 midrange. I built mine from scratch from the catalog and what I remember is the midrage and tweeter are horns. With a 12" and 10" woofer.

Click to expand...

The 7's I had were the same way as yours. In the early 80's they did away with the horn. The 7's are great speakers. I sold mine a year or so back and sorta wish I still had them. I won't ever part with my 8's though, they are beast mode!

Wish I could here a set of S50. I wonder if Infinity mids and tweets would work in your unit satisfactorily in your rebuild.

So far I haven't seen any Infinity raw drivers over here. My choices are complicated by my location. I'd prefer to buy here in the EU if I can find suitable drivers here. Shipping costs from the US plus 19% VAT from the friendly Customs people add up quickly. At the moment I'm trying to decide between a pair of Wavecor_WF168WA01 or Scanspeak 18W/4434G00. Both run about €60 a piece. Inside my budget.

My tweeters are ok at the moment, but I want to eventually find replacements for my 10". The W1038R from Madisound looks perfect, but by the time I got a pair of them shipped over here I might as well buy something more expensive directly here in Germany.

Cheers

I didnt realize you lived in the EU. If local I was going to try and get them to you to try if parameters were correct. You are correct and on the right track. Sorry.

OK. So far I have the speakers completely disassembled, and all except the 12" stored safely for later. My plans at the moment go in 4 steps.

1) The cabinets are still in reasonably good shape. Some pencil marks appeared as my kids were growing up, a little weather damage on one box, not so bad. I've bought 320, 400 and 600 grit sandpaper, furniture oil, and still need some wax of some kind. Applying that stuff should take care of the outsides. I also bought some gold plated brass binding posts for the rear connections and need to open up the rear openings a bit and mount them. Today I bought brass screws to mount the crossovers (something that I didn't think of 30 years ago, used steel screws back then) and some silicone sealant for the inside corners. It's not a non-solvent based silicone, but I'll just leave the cabinets open for a couple of months to cure. And I found a nice stable piece of hardwood to make some braces between the front baffles and the back wall between the woofers, something that I also didn't think of doing 30 years ago.

(The existing cross brace is placed just low enough for clearance behind the 10", and just high enough to pass a brace to the thin spot between the woofers, it's centered about 35 cm above the cabinet floor, something that I forgot the mention earlier.)

2) Buy replacement midranges asap, and a later on new 10" woofers.

3) For the short term simply replace the caps in the crossovers with new elcos, I've found an outfit here where I can buy replacement Mundorf caps for around €17 total. And they have 10 watt MOX resistors for €14 for all 10. The tweeter inductor is mounted right next to the mid coil, so I'll remount them on their sides 90° to the midrange coils. That's it for the short term except using longer 2.5mm wires internally for the speakers so I can mount the crossover flat on the bottom of the cabinet. Depending on what I find for midranges I will probably remove the 2 ohms of padding on the mid circut.

4) Long term planning is to build completely new crossovers with all poly caps, mox resistors, and 2 to 2.5mm air core inductors. I figure that'll take a good €600, so that will realisticly take me till next spring or early summer to realize.

That's the plan, I have no idea what reality and She Who Must Be Obeyed will dictate.

Cheers

Yeah, I moved from the PNW to Munich in '97. Beautiful city. I love it here.

€600?

Yes. Even if I use the cheapest Jantzen Cross Caps for everything except the 2 micro on the tweeters and perhaps Z-Superiors on them I'm looking at about €120 for the poly caps, and reuse the mox resistors, then come the inductor coils. 2mm .33mH aircore Mundorfs (about 12 guage) will run me €35 for a pair, and 2.5mm 2.7mH (10awg) for the mids = €155, and 2.5mm 3.3mH for the woofers are €173 for the pair, and another €89 for vacuum impregnation, and I'm at around €600. Gulp.

But I really want to hear what happens with really low resistance air core coils. Mind you this is all theory for me I've never done this before. My friends look at me a little funny and glance over to see if my liquor cabinet is looking particularly empty, but...

Anyway, one step at a time. Two by two, hands of blue.

Cheers

edited 26-09-13 - corrected spelling error

So here's a question for anyone, looking at the crossover schematic, those 2 33micro caps and the 4 ohm resistor that are in parallel with the woofers. Is that a Zoebel (sp?) circut? Some kind of load balancing circut?

Would that mean that if my existing 10" woofers don't have the same t/s values as the W1008Ps (and I doubt that they do) that circut is no longer valid/correct?

Thanks,
Bratwurst7s

Wow, great thread, I have the Thirties and will at some point want to update them.

Paul Johnson at the loudspeaker store in Kent WA is a great resource for these and the later nesterovic speakers.