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Old 30th December 2003, 01:45 PM   #1
fireman is offline fireman  Canada
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Question Minimus-7 retrofit

A friend of mine was going to throw 2 black Minimus-7 in the trash after buying a Bose home theater on Boxing Day.

I know these are not the greatest but they do a pretty good job for their size. Being on the lookout for my next DIY project (most probably TB's, probably ISA enclosures) I thought it wouldn't hurt to grab these Minimus before they end up at the landfill site.

After removing the front grill, I noticed that one of the tweeter is damaged. The soft dome has been crushed quite a bit. First question: In such a tweeter, is the dome actually doing the "real work" or is it just a protecting membrane ? Would "pulling" the dome back in place do any good or shoukd I simply replace the tweeter ? What would be a good replacement tweeter for this speaker ? The cabinets badly need a new paint job. What type/make of paint would you recommend ?

Last but not least, I read somewhere that there are "upgrades" for these speakers. IIRC, it mostly concerned the XO. Do they really make a difference ?

As always, thanks for all the help.
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Old 30th December 2003, 06:52 PM   #2
Stephen is offline Stephen  Canada
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Default Minimus 7 refit

Hello Fireman

The domes are actually producing the sound. Therefore the tweeters should be replaced, if they still sound distorted after pulling them out with a needle. Always replace tweeters in pairs.

The main problem is finding a tweeter to fit the box, since the mounting plates on Minimus tweeters are rectangular, not round or square, like most tweeters. You may have to make a cardboard adapter for the hole, and you may have to cut off two sections from a tweeter that has a round mounting plate (I used a hacksaw).

Also, choose a tweeter with fairly low sensitivity to match the woofer. Neodymium magnet tweeters are now becoming affordable, and they often have sensitivities in the 85 - 89 dB/watt range.

I haven't noticed a great improvement when I upgraded the crossover, as the woofer has a built-in smooth rolloff in the high end.

I've refitted these speakers with different woofers with good results.

Black laquer paint should work.
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Old 4th January 2004, 03:04 AM   #3
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Default Minimus 7s should be fine

I have had Minimus 7s for 23 years and they have been beat to crap for most of that time. They still sound fine with the domes crumpled. I now have them hiding in a veneered box with a pair of the Minimus-7 replacements (AV-44) in the box too. They are arranged d'appolonito style with the woofers on the top and bottom and the tweeters in the middle. The Bass reflex Av-44 makes too much port noise so I high passed it with a 220 uF cap to get rid of the lows it can't really handle anyway. This combo sounds great!!! Your friend got rid of better speakers than the ones he got for xmas...despite the price.
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Old 4th January 2004, 07:17 PM   #4
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Honestly, on the paint issue, I think some black spray paint would do fine... I don't know about your models... but my Minimus 7's (which are my current computer speakers powered by a Yamaha RxV670) appear to have a metal cabinet... I would think some Rustoleum, either regular or Hammer Finish would look sweet. Perhaps the hammer finish bronze...

...
...
...


DAMNIT! Now I wanna paint mine! I hate how much I love this board!
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Old 4th January 2004, 08:26 PM   #5
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Stephen: Replacing the tweeters, that's what I had in mind. Now I need to find a source for the replacement drivers.

Gringo: Good idea. I have another pair on loan to my in-laws. If I can get a hold of them, I think I will try your idea.

HiggityHank: The hammer finish sounds great. I'm not sure about the bronze color though. I've never actually seen it. I might have to try it on something else first.
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Old 5th January 2004, 12:41 AM   #6
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Default Re: Minimus 7 refit

Quote:
Originally posted by Stephen
The domes are actually producing the sound. Therefore the tweeters should be replaced, if they still sound distorted after pulling them out with a needle. Always replace tweeters in pairs.
I wouldn't actually use a pin to pull a dome out... if a simple "Monica Lewinsky" treatment doesn't pop them back out, you should be able to pull them out, disassemble them, push the dome out from the back, and then reassemble them.

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Old 5th January 2004, 05:58 AM   #7
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The hammer finish bronze is more a charcoal gray color... I don't know what they were thinking... but it's odd. Perhaps they were thinking of much older bronze... or just wanted a clever name for "Metallic Charcoal Gray"

Why can't companies name anything it's actual color anymore... it's gotta be all "Super Ultra Chameleon Flourescent Muave Pearl" instead of "Blegh..." like what everyone else will call it.
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Old 5th January 2004, 06:14 PM   #8
Stephen is offline Stephen  Canada
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Default replacing tweeters

Hello Fireman

I agree with dave (planet10). Disassemble the drivers and pull the domes out-- assuming that the domes and voice coil assemblies can be separated from the magnet assembly. Try a pin as a last resort.

The difficulty in replacing the Minimus tweeters is their oddball rectangular mounting plate. It would nice if you could adapt the plates to other tweeters. I envision removing the mounting plates of the replacement tweeters and attaching the Minimus plates with "Goop" glue. Best of luck.

Stephen
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Old 5th January 2004, 06:40 PM   #9
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Default Re: replacing tweeters

Quote:
Originally posted by Stephen
It would nice if you could adapt the plates to other tweeters. I envision removing the mounting plates of the replacement tweeters and attaching the Minimus plates with "Goop" glue.
2 problems with the goop route -- you are never going to disassemnble them again, and it has a "thickness" that could interfere with proper seating. Better to drill new holes in the Minimus bezel to match the replacement tweeter.

I wouldn't be surprised if you could get an actual replacement from RS (you might shudder at the price thou).

Just checked -- doesn't look like i have a replacement tweeter (at least on 1st pass)... i did have a replacement midbass i used to fix the pair i have.

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Old 5th January 2004, 06:45 PM   #10
Stephen is offline Stephen  Canada
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Yup. More work, but a better solution than Goop...thanks, Dave.


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