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Dan's total noob speaker refurb project

DRMcD

Member
Looking for opinions on what to do with these:

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They are Synergistics S-52B's from 1979-80, as far as I can tell. I've learned that RTR might have made these in California, and they are considered so-so "house brand" speakers for their time, but they rocked whatever house I was living in from 1985 to 2002, when the surrounds finally disintegrated and I retired them. I had one driver replaced by a shop in 1992 or so (the blue one), and only last year pulled the one driver to see what I could see, in order to get ideas on how to refurbish these. I want to do all new drivers, crossover, wiring, and finishes.



The ideas I have:

Tweeters: you'll see an extra tweeter on each side of the cabinet, a total of four per. I liked the imaging of these - whatever room these were in, they shined.

Thinkin bout staying with the 2" holes, and use big cone tweeters like these have on the sides, and use piezos or domes in the front. Have the crossover split just low and mid highs (6-10 kHz) to the sides, but full tweet range to the fronts.

Open to any ideas on brands, types, etc...


Woofers: these are 8", and AFAIK both woofs in each were wired as such - it sounded like they both handled low and mids.

Thinkin bout staying with 8" drivers, but have crossover split lows to bottom, mids to middle, maybe add an extra level control for the mids (these had one for "tweeter"). Or, stick with how I knew these - crossover treats them as both woofers and mids.

I'm thinkin Cerwin Vega woofers, or a woof and a mid. Open to other brand ideas, would rather stick with modern drivers rather than vintage. More interested in accuracy than window-rattling. Would prefer synthetic materials for longevity. These cabs are not ported, so I know I'm going to have to visit some infinite baffle formulas before buying drivers.


Crossovers: I haven't started investigating them yet, and I would think the extra tweeters and the low/mid idea for the 8's complicate things. I would consider DIY, but for my skills and free time, I'm probably looking at something already built and I can adjust. I would also consider just using a new crossover wired identical to what's there now.


Cabinets: the tops are walnut veneer, and many plants and/or beer bottles were parked on them. The bodies are MDF/particle board, and show no signs of moisture damage.

Again with time and skills, I could veneer, but I'm thinking stripping it and using some sort of cap - something carved out of one piece, that just slips over the top and bottom, and extends them about an inch square more.

Smooth out driver holes around tweeters, or find ones that will cover existing holes. (Can you tell I don't want to modify the cabinets? :D)

The grilles had molded plastic "Synergistics" logo badges (like what's on the foil in pic 2) but they disappeared ages ago. They are three piece wraparounds, with typical 70s tight black knit polyester. Would probably be leaving the grilles off to admire my handiwork, but will want to replicate what's there now. Salvage the foil and relocate to back.

No veneer on bodies, just new black paint (something thick and matte, like maybe automotive undercoating)


I want these speakers to be my A's with my 9100. I also have a pair of Cerwin-Vega bookshelf speakers that I want to use as B's, or maybe even park them to the sides of the S-52Bs on stands someday. I'll post pics/descrip of the CVs in another post. I've been using the CV's as A's since I retired the Syns in 2002.


My budget: $1000 at the very max for the pair. I'd rather dump that kinda coin into a project like this - my brother will freak when he sees/hears these and the 9100 reborn (and be jealous he gave this stuff away).


Discuss :D
 
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The critical first step of this is the selection of the woofers. At your budget you should be able to get some mighty fine drivers PROVIDED the match the cabinet's internal volume well. That's the rub, you need to get that internal volume and then do some work with the T/S parameters of various drivers available to find a good match. A program called WinISD can help you with this quite easily and its free to download. But the starting place is the internal volume and the tool to compare different woofer pairs with the cabinet.

Shelly_D
 
Check out Zilch's econowave thread. You can always cut new baffle boards for the drivers. Sandwich over the old ones:thmbsp:
 
The critical first step of this is the selection of the woofers. At your budget you should be able to get some mighty fine drivers PROVIDED the match the cabinet's internal volume well. That's the rub, you need to get that internal volume and then do some work with the T/S parameters of various drivers available to find a good match. A program called WinISD can help you with this quite easily and its free to download. But the starting place is the internal volume and the tool to compare different woofer pairs with the cabinet.

Shelly_D
Understood - I want to keep these closed, as that's what I was used to with them.

Issue: I'm on a Mac. After looking around, there's no good/easy OSX alternative for WinISD. I'll have to get some sorta emulator like Wine cuz I don't want to hassle with dual boot.

Really Dumb Question: I can measure the outsides of these, and subtract wall thickness, to get internal volume? I have numbers on that - in fact, with a bit of free time tonight, I did some more inspection... I might not want to dump money into these...

First off - how these were crossed overed:

xover.jpg

Not impressed. This looks like the dirt cheapest way to get it done. Can't believe I was listening through that all these years.

But it tells me what I thought about their imaging - both 8's were woofers, and all four tweeters got the same thing. I think I still want to make the top 8" a mid, though. But if I stick with both as woofers, I can use the C-V bookshelfs like a floating mid, separate from these cabinets.

Oh yea cabinets:

MDF1.jpg

MDF3.jpg

MDF2.jpg

MDF4.jpg

The MDF is actually kinda fragile. IIRC, this stuff doesn't last forever. Can I fill the missing areas in with putty?

What's more, the tweets are glued in - the two screws were more for show, I think.

And in the bottom pic, you can see the unfinished veneer on the cabinet floor - looks like they veneered squares, then simply built over it, and stained the outside.

The measurements I have are:

13 1/4" wide
30" tall
12" deep

The front panel is most definitely night on the ruts 3/4" thick.

The side panels butt to the front panel, and look like 3/8" or 5/16".

The back panel fills between the sides, and for some reason looks like 7/8" or 15/16".

There are staples attaching the sides to the back. I can't imagine these were not glued as well, but judging from the cheapass crossover...

@powerman: yeah I might have to look into those. Maybe I had high hopes for these cuz of the sentimental value.

Sentimental value gets expensive :D
 
You might want to examine that blue 8" woofer a little more closely. Marantz used blue speaker cones... it'd be a shame to lose one of those.
 
An 8" sub woofer with an 8" full range and a super tweeter would be interesting.
I just took a quick scan of the Econowave threads - I was hoping to not modify the holes too much. Hence why I was thinkin an 8" midrange, too. But something tells me it complicates the crossover, and would require a level control for extra tweakage.

There is no internal baffling in these (other than the fiberglass which I'm still itching from).

I've read that the tweeters in these might have their qualities, but I know at least one of them in each cabinet didn't work when I retired them. And with them glued in, I can't imagine removal without destroying the holes. That could be limited to the lip cut into them, like the woofer holes do (maybe 1/4' depth)... just carve those out with a jigsaw... but yea, all new tweeters, and considering I now know that they were all wired alike, keep all 4 the same type and same range.

You might want to examine that blue 8" woofer a little more closely. Marantz used blue speaker cones... it'd be a shame to lose one of those.

Hm... it would be an orphan, tho. IIRC, Speakerworks in Chicago did it for me in 1992. Pics:

blue1.jpg
blue2.jpg
blue3.jpg
blue4.jpg

No Marantz markings on it. The dust cap is flat, nylon screen in a molded ring. Rubber surround. Pretty good shape overall, actually. I'll save it, if it really is Marantz and someone's lookin for one.



More I think about this, more I should just take the $1000 and go auditioning for new (or new-to-me) ones...

But then I lose the DIY satisfaction...

Urgh :D
 
You might have a similar performing speaker to the modified speaker if you spent $1000 on a new speaker.
$1000 on a used speaker might outperform the modified speaker.
$1000 on a new DIY speaker will outperform everything above.
 
Here are pics of the Cerwin-Vega bookshelfs I've been talkin bout:

cvfront.jpg

cvfront2.jpg

cvback.jpg

I wouldn't mind putting these on stands to either side of the S-52B's, and keeping the new crossovers simply two-way, with the S-52B's wired for two woofers. Have these act like fillers.

Also wouldn't mind if someone could ID these - I posted in a CV forum a few days ago, but no one's replied yet.

They are 6.5 woofers, 1" dome tweets. The only way I know they are CV is the badges on the grilles, which look authentic - but the lack of a red woof surround, and the fact someone removed the back labels (you can see evidence of where they were in the pic) - that all tells me these might have been either early models, or a value line, or even knockoffs.

Up in the air about these - they've been my main speakers in my mancave for the last 10 years or so. I like them, but not as mains. I could incorporate them into the refurb scheme, but then I'm dependent on a second set of speakers.



Yikes almost 1 am - I gotta call it a night.
 
You might have a similar performing speaker to the modified speaker if you spent $1000 on a new speaker.
$1000 on a used speaker might outperform the modified speaker.
$1000 on a new DIY speaker will outperform everything above.
Well spoken :D

And understood... the biggest limit I have is woodworking from scratch - why I was looking to salvage these cabs and the existing holes. I would consider some mods, like powerman said - do a sandwich thing...

I have a one-car garage space to work in (when the car ain't in it), and only super basic power tools - drill, circ saw, jigsaw, Dremel, a cordless drill with some attachments.

Guess I got some more thinkin to do.

OK now I go to bed :D
 
It is better to limit yourself only by budget, and not by finding a driver that works in your existing cabinet which, hopefully, have a sock to cover the drivers.
 
It is better to limit yourself only by budget, and not by finding a driver that works in your existing cabinet which, hopefully, have a sock to cover the drivers.
You mean socks like with the pom poms, right? :D

I covered those here:

The grilles had molded plastic "Synergistics" logo badges (like what's on the foil in pic 2) but they disappeared ages ago. They are three piece wraparounds, with typical 70s tight black knit polyester. Would probably be leaving the grilles off to admire my handiwork, but will want to replicate what's there now. Salvage the foil and relocate to back.

No veneer on bodies, just new black paint (something thick and matte, like maybe automotive undercoating)
I'd like to keep them like they look now. And after thinking about their construction, I'm wondering if I could do a better job from ground up my first time out.

I also know I can bite off more'n I can chew sometimes, so:

Budget drops a bit. Average built cabinets like these won't allow pricey drivers to shine. Rehab cabinets, get them into shape for future driver swapping if I find I'm dissatisfied with early purchases. Make the math of these boxes work before I start gettin fancy.

Still fishin for suggestions... thought I'd hear all kinds of crazy $h!t here :D
 
I've tinkered with a few epi speakers and the beauty of them is the simple crossovers and that the same "Burhoe module" can be used in a variety of sized boxes. Or multiple modules can be used.

To keep it simple, I'd use 2-8" epi woofs and 2 epi tweets on the fronts. Then plug the holes in the sides. I don't see any ports, but if so, they would need to be plugged also. Use the same crossover schematic as some of the dual module EPI's. Then enjoy!

Not real creative, but simple and effective.
 
I've tinkered with a few epi speakers and the beauty of them is the simple crossovers and that the same "Burhoe module" can be used in a variety of sized boxes. Or multiple modules can be used.

To keep it simple, I'd use 2-8" epi woofs and 2 epi tweets on the fronts. Then plug the holes in the sides. I don't see any ports, but if so, they would need to be plugged also. Use the same crossover schematic as some of the dual module EPI's. Then enjoy!

Not real creative, but simple and effective.

I like this idea... nope, no ports, want to keep it that way.

I also like the fact that EPI is made in the USeffinA. Yeah I know the 9100 was made in Japan.... that's not the point. Point is now :D


So I got Vas at 2.309 cu ft, 65.38 liters. Do I have to divide this by 2, for two woofers? The 2.3/65 number includes a simple shelf brace between the woofers (or maybe above them?).


Leave it to me to complicate it: I want to keep the side tweeters, but I think if I use all new piezos or domes or somethin, it's gonna get harsh/fatiguing. Use a mellower driver, but more of them. Add level adjust to the crossover for the sides, leave fronts normal.

Because of the existing tweets being glued in, I'm gonna hafta carve out the rabbett to get them out - leaving me with 3.125 holes.


And I have it in my head that I don't want both 8's doing woofer duty -somethin like the bottom is doing 30-1000 Hz, middle 700 Hz-10 kHz, tweets 10-20 kHz. Rough numbers, I dunno what I'm doin yet...

As soon as I had a Vas number I went shoppin at Parts Express, partly to start wrappin my head around how T/S figures work. Tried their speaker wizard - it gave me this:

1) Goldwood GW-8028 8" Butyl Surround Woofer 8 Ohm
2) Morel MW-266 8" Poly Woofer

The Morel's figures look like they'd work, but at $125 ea. = too high.

The EPI Pro 001 looks spot on for my needs. Would consider making it a one stop shop and trying his PRO 002 M2 tweeter, but they only handle 40 watts? My 9100 is a '74 so it's 60 watts. This where padding the crossover comes in? Cuz I don't have to worry about the 001's - they are 175.

And I see lots of fish in the tweeter sea...
 
Check the PE "speaker buyout" section. You should be able to snag a Peerless india or Vifa for cheap. If not, move away from the Goldwood to a Dayton, they are very good. Ray W has used the Dayton to great success.
Tweeters can be had in all different types of mounting schemes. If it was me, I'd be looking for a Scanspeak or Seas with a mounting plate, maybe a Vifa, no piezos need apply. Check out Zaph's tweeter mish mash for ideas.
 
Lot's of what you are wanting to do will be depending on your comfort level with crossovers. With a variety of different drivers and cutoff frequencies, especially mixing several different tweeters of different styles in the same cabinet, it will take some "pretty creative" crossover work.

As for epi drivers, some can be found pretty cheap if you buy used. If you decide to buy rebuilt ones, Human Speakers does a great job.

Good luck.
 
Check the PE "speaker buyout" section. You should be able to snag a Peerless india or Vifa for cheap. If not, move away from the Goldwood to a Dayton, they are very good. Ray W has used the Dayton to great success.
Tweeters can be had in all different types of mounting schemes. If it was me, I'd be looking for a Scanspeak or Seas with a mounting plate, maybe a Vifa, no piezos need apply. Check out Zaph's tweeter mish mash for ideas.

Mish mash = thanks! Very useful, I got a lot out of that. Comparo. Tweeters will take more thought - I read up on diffraction and right angles. Didn't realize some HF drivers can go down to 1300 Hz.

Lot's of what you are wanting to do will be depending on your comfort level with crossovers. With a variety of different drivers and cutoff frequencies, especially mixing several different tweeters of different styles in the same cabinet, it will take some "pretty creative" crossover work.

As for epi drivers, some can be found pretty cheap if you buy used. If you decide to buy rebuilt ones, Human Speakers does a great job.

Good luck.

At this point, I'm thinkin not EPI themselves, but Human's raw drivers. 4 woofs, $300-400. No funny business crossin over mids to the upper 8, keep both LF like they were.

Tweeters would be all identical, just have a level control for the sides.

Thus, the crossover stays a simple two way.

Maybe another $400 max for the 8 tweeters, so in the $30-50 range each?

The last $200 into the crossover/cabinets/grilles?

Am I lookin at $1200 here?

Does anybody really know what time it is? :D
 
If so, I can't imagine why...


So I'm on Many Moons Audio's list for an October rehab of my amp. Was kinda waiting on an opinion from Human Speakers, and still open to suggestion.

My favorite thing about this amp and speaker combo was what I think is called "soundstage". I always looked for max separation in whatever room the system was livin in, and have always had this 15 foot triangle in my head when setting that room up for a sweet spot. Probably picked up from a 70's audio mag.

I just want to keep that soundstage the way it was - just make it sound newer. Refreshed, maybe.


C'mon, let's hear some idears :D
 
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