Technics SB7000 midrange- Availability or Info?

I keep wanting to get a pair of Technics SB 7000's up and running- but I have no mids. Now, assuming I'm not going to find a used pair anywhere, can anyone point me in the direction of a suitable replacement. One cabinet had an empty hole and the other one had a burned out mid. The info on the back of the mid reads: Technics cone Squaker, EAS-12PM70s. I don't even know if they're 8 ohms (I assume they are!) They have a 5 1/4" square frame, paper cone, foam surround and a free air resonance around 70 Hz.

Thanks in advance for any help.

What exactly is the cutout diameter in the cabinet?

Also, these have midrange level controls, no?

Regards,
Gordon.

Hi Gordon;

The cutout is 4.4". I guess the midrange frame is actually 4.75" across. (Sorry, I thought I read that it was 5.25" across. Senility surfaces again!)

And you're right, they do have level controls for the mid and tweeter. I think they're about 90 dB efficiency for the whole system but that's going by my questionable memory.

What I don't know is; if the speaker is rated at 90 dB/W/M, and you have an L pad who's flat setting is 1/2 way, then do you assume you need a mid with a sensitivity of about 93 dB/W/M to allow some boost to the output if needed to approximate the original squaker?

Sign me: Puzzled by Panasonic

Lab,

Check out this Austin, TX CL link for SB7000A's for sale, cheap. Very cheap for a parts donor!

http://austin.craigslist.org/ele/256555482.html

Standard disclaimers and no affiliations whatsoever.



sae2922

That's a great deal. Someone should jump on them.

Man, to heck with parts donor... those would be EASILY cleaned up and fixed up! Looks like it's all there, in pretty good functional shape!

Regards,
Gordon.

lab said:

Hi Gordon;

The cutout is 4.4". I guess the midrange frame is actually 4.75" across. (Sorry, I thought I read that it was 5.25" across. Senility surfaces again!)

And you're right, they do have level controls for the mid and tweeter. I think they're about 90 dB efficiency for the whole system but that's going by my questionable memory.

What I don't know is; if the speaker is rated at 90 dB/W/M, and you have an L pad who's flat setting is 1/2 way, then do you assume you need a mid with a sensitivity of about 93 dB/W/M to allow some boost to the output if needed to approximate the original squaker?

Sign me: Puzzled by Panasonic

Click to expand...

Due to the midrange gain in a typical 3-way crossover (the woofer and tweeter "help" the mid, so the mid doesn't have to be as efficient as the tweeter or woofer), anything at or above about 88 dB should be fine in that speaker. You might have to turn the L-pad up a bit higher for an 88 dB driver, but it should still be within working range.

Here's one driver you might want to look at for replacement:

http://www.mcminone.com/product.asp?catalog_name=MCMProducts&product_id=55-1505

I've used those fiberglass-cone MCM drivers before, and they seemed to work well. Should be a drop-in fit (or at worst, 5 minutes of filing with a rat-tail file on the inside of the hole)...

Regards,
Gordon.

Damn! Those are the virtual clones of my Technics ('cept mine are lacking mids and dirt). Too bad I live about a light year away.

You're right about the MCM mid, Gordon. I had one on a shelf and it's very close in dimensions except the frame is slightly rounded so it might take a bit of routering to make the lower edge fit into the woofer cabinet's roof. Nice rubber surround and the frame looks alot like the woofer's. Wouldn't you know I only had one on hand. I suppose I should wire it up and see how it sounds before grinding the cabinet. If it's not bad I could wait until I'm ordering some other stuff from MCM and toss it on the order. Hate to pay shipping on a single mid.

$60 for a complete pair of SB7000's? That's almost sacrilege! Works out to about 42 cents a pound.

Seems to be parts for SB7000s here

http://catalog2.panasonic.com/webapp/wcs/stores/servlet/SupportModelSearch?storeId=11251

click 'parts locator' on left.

Good luck

If your going to replace a mid with a none standard one I would replace both of them. Mid range is very critical and your balance, overall voice and imaging will suffer unless your mids are matched pairs.

moof: I tried the site, but it said my model number (and later my part number) were not active. I guess they're just discontinued, but then it is at least 30 years.

kfa888: I will definitely change both mids when I settle on a replacement. As the speakers only came to me with one burned out mid and one empty hole I had to do a little creative reconstruction. The original midrange that I have isn't even really trustworthy because I replaced the voice coil and spider with what I thought would be a similar to the one's that were damaged. I did that primarily so that I could test the driver's resonance and get a ballpark idea of the sensitivity of the driver. Even now, of course, I could be way off, but hopefully it'll give me something to go on.

Hi, I'm new here but have had the pleasure of finding information on many a subject on audiokarma.org before. Great site!

I'm hoping to see this old thread resurrected, the link to mcminone.com doesn't work anymore and I can't see any speaker on the site that would fit the Technics.

lab, did you find any suitable replacement midrange speakers for your sb7000's? I found a set sb7000 on a fleamarket, and bought them for almost nothing!! The are in great condition, except for a blown midrange. The tweeters had been replaced with Scan-Speak D2905/9000, and they suit the cabinets nicely with a custom fit, and they sound great! If I only could find replacements for the midrange speakers all would be well.

I've been searching a while but can't find anything that fits with the square frame hole on the SB7000..

Hi marauder, welcome to AK! Congrats on finding a pair of 7000's, I use a pair every day, and I think they're incredible for 35 year old speakers.

Interesting that your tweeters have been replaced with the Scanspeaks. Those are round, but the originals were rectangular. But if they work well, that's what matters. At this point, I'm not sure finding an original midrange is an option, unless you can find one that needs to have the surround replaced. I was very lucky in that my pair came from an elderly woman's home, where they saw little use over the years, and no abuse whatsoever. So they were practically like new. This is close in shape, and cheap: http://www.parts-express.com/pe/showdetl.cfm?partnumber=299-416.

Good luck to you, hope you really enjoy the speakers!