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Speakerlab S7s Rebuild and Modding (Ribbon Tweeter Model)

Today I finally installed the new mids. And of course there arose a complication. I hadn't noticed that the new mids have a bit larger installed diameter in the cutout. 149mm and the cutout is 143mm. So I set my dial calipers to 3mm and used them to scratch a line marking a new 149mm dia on the baffle and then used a white marker to highlight the area needing to be removed. The depth of the relief doesn't need to be very deep except for where there is a kind of decorative tab on the machined areas of the basket that can be seen in the 3rd pic in my last post. So I just used a half round wood rasp file and angle filed the cutout about 6mm deep and the 3mm extra dia. So now I have a cutout with a dia of 149mm tapering down to the original 143mm. Where the 4 frame tabs are I had to file the 149mm straight down with a square file.

Of course I got carried away with working and forgot to take any pics after filing. If I pull a mid for any reason later I'll try to remember to take a few photos. I didn't re-use the dacron fill but instead substituted some fibreglass salvaged from some empty Canton speaker cabs that were sitting around. I still haven't gotten over to buy any fibreglass but now at least the mid enclusures are about 90% filled with it.

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So the difference in sound? A little bit tighter in the mids. Not a big change at all but I really wasn't expecting any earthshattering improvements. After all the new mids are electrically and mechanicly the same as the "old" ones with the only difference being the heavy cast aluminum basket. But now all 4 drivers are as good as I can make them. Sometime in the next month or 2 I'll have to go over to the hardware store and buy some fibreglass to restuff the main part of the cabs. And then get off my butt and start taking some acoustic measurements.

But at the moment I'm very pleased with the sound here. Very very clear and detailed, great sound all around with very tight bass. The grin factor is very high. Oh and just before Christmas I managed to buy a Yamaha M-70 power amp with some kind of damage to the right channel. So now I have a Yamaha CX-600 pre-amp with a dead transformer and a M-70 power amp with unknown amounts of damage to one channel. :whip::D But I didn't pay very much for them and they are optically in very good condition and I hope to be able to repair them in the coming months.

Cheers,
James
 
So it's been just a few days short of a year since I did anything with my 7's except listen to them. The time in between has been spent improving the source, first with a modded Denon DCD-1290, and now with a modded DCD-2700.

Last week I finally got off my rear end and bought a bale of fibreglass batts and today I beat the stuffing out of the speakers. Well I took it out anyway. And replaced it with the fibreglass, pretty nearly full. They are closed up again now and my amp is warming up. I don't expect to hear much of a change, but am hoping for a little improvement in bass tightness. More later...

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Cheers,
James
 
Oh, and now for a little Woofer Porn. I sometimes forget just how massive those W1208R's are, until they get put unto perspective. :beerchug:DSC03345.jpg DSC03346.jpg DSC03348.jpg

The last pic is of the old dacron fill that just got removed.

Cheers,
James
 
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Hi James,

You've done a great job on these. Sure wish I could hear them but Munich is a bit far from Seattle.

Did you get the Yamaha preamp and amp working? Just curious as I have an M-80 and a C-4.

John
 
Hi John and Valveglow! Long time no hear. Unfortunately I haven't been able to get the CX-600 working (yet). I haven't given up but had to set it aside for a while to think and get some other projects out of the way. The M-70 is sitting just above my head on a shelf waiting also, but I'm getting closer to being ready for it. In the mean time I've been saving my pennies and have enough to think about buying a CX-1 when I find one.

If either of you ever find yourselves in southern Germany it would be a pleasure to have you stop by for tunes, brews and some of Wife's fine cooking.

Cheers,
James
 
Subjectivity can be tough. It's so hard to set aside wants, expectations and wishes. Nonetheless...

I listened to the first Dire Straits, the first Rory Gallagher, and Working Man's Dead, in that order.

My first impression was that there was less bass than before. But as I got into it I realized that in fact I had gotten what I wanted, it was just that a bit tighter bass had also translated into a bit less boomey bass. And that was letting the mids and highs shine through a bit better. But my expectations had gotten in the way of hearing that at first. I hadn't ever thought of the speakers as being boomey, but I can't think of any other way to explain it. A subtle change that adds to the pleasure. For an investment of €14 and 3 hours of time it was well worth it. Another small step forward.

I've been procrastinating and letting myself get sidetracked, but one of several Audio Resolutions for the next year is to get off of my ass and get started in measuring things, get some facts to objectively offset subjectivity. Time for some facts.

Cheers,
James
 
You may already have the measuring equipment you need, but if you will be in the market I can recommend the Woofer Tester from Smith & Larson. A friend also has the Parts Express version but suggested to me the S&L version. Do you have the S7's wired for biamping? You might have some fun with a miniDSP for both an active crossover and for it's neat EQ functionality. I use one in my subwoofer amp signal path since I'm a bit of an irrational purist for the mids and treble. Just tubes and a simple circuit. I use a Linkwitz Transform EQ function for my sealed box subs. With it you can have the Q (damping) you like, bass boost if you want and the low pass. I use all three in my sub circuit.
 
Actually, based in part on your recommendation, I bought S&L's WT2 early this year. It's a very good program/tester with one exception. It's one of the few programs that I've absolutely not been able to get running in Linux under Wine. Back then I used a borrowed laptop to run it but had to return it (the laptop) after a short while and haven't used the Program since last spring. Interesting that you would bring it up because just today I set up a dedicated laptop with a legit copy of W7 just to run wt2 and REW (Room Eq Wizzard) to do more testing with.

Cheers,
James
 
Oh, no they aren't wired for biamping. Thought about it seriously but then took a realistic look at how much room I have for amps, and then stuck with a simple single connector. On the other hand, I am also an irrational purist concerning mids and highs and did go somewhat overboard with the crossovers. Fact is they sound (imho) extremely good in that regard, but the combo of the MHT-12 ribbon tweeters and Wavecor mids has turned out to be fantastic. I take it that both of them are little known back there but can highly recommend them.

Cheers,
James
 
with AS sometimes if you change the damping material you get less midbass but a little more bass extension. a nice tradeoff imo.

as for eq, i always boost low bass in the 18-30 hz region with large AS speakers..
 
Thanks nexus. When you say midbass what freq ranges do you mean exactly? These are crossed at ca 350hz. But what you say would explain what I heard, it seems that the mids and highs are a little more prominent. Makes me think that perhaps there was a bit of a freq hump at the crossover point. This is where it's past time that I started doing room and response measurements. I have the usb mike that miniDSP sells and REW is pre-loaded with a calibration file for it. I just need to get busy and learn how to use it.

Cheers,
James
 
well midbass is generally thought to be above 55hz (but not technically).

HSU offered a midbass woofer to be used with their subwoofers. it operated at 50hz and above.

at the time Speakerlab was marketed the emphasized midbass was in demand for rock albums of the day. AS type of speakers are generally thought to be conservative in the midbass.

Speakerlab did publish one of their many tech papers on speaker damping. i remember one person asked if they could add more fill to the Sevens..
 
Thanks! At the moment the sound is interesting. I'm going to have to just play a lot of music and evaluate them. I'm going to need to open them up again in the next week or 2 and may try removing a bit of the stuffing just to find out what happens.

I have a friend back in the states that has 1) my original ribbon tweeters, 2) my first pair of steel frame Wavecor mids, 3) my original crossovers, 4) 2 pairs of W1208R woofers, and 5) an extensive woodshop. Guess where this is going. So I need to test 2 1208R's in parallel with WT2 to see if any crossover changes need to be made, and find out how much larger the cabs would need to be to make 2x 1208's happy.

Cheers,
James
 
c-atle-79bay said:
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.
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Would that be Paul that worked at Magnolia hi-fi and the Klipsch factory? And works out his house? He and myself had a mutual friend and Paul and I have only spoken on the phone. But my ADS L-780 2's need some t.l.c., so i'll be seeing him soon. But he doesn't know I just got these yet (pics). I'm more than happy with the 4's. Will D.IMG_20161226_112526.jpg IMG_20161226_112501.jpg IMG_20161226_112405.jpg IMG_20161226_112146.jpg
 
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