Minimus 7 replacment woofer and tweeters

As you can see, I am a new member. I joined this forum after many hours of internet searching regarding the Minimus 7s. I have a pair and it appears both my woofers and tweeters are blown/fried/destroyed. I was planning to build a Zilch crossover but also need to pick new woofers and tweeters. I have searched the forums and have only found a few suggestions and they seem more along the lines of what is a good fit or a good option to use with existing speakers.

This is my first go at this and I realize I have a lot to learn. I have this idea that I will either end up with some really good sounding speakers OR a small disaster.

I plan to start by building the crossover I was thinking of spending around $100 on the Speakers. I would really appreciate your input. For woofers, I was looking at:
MarkAudio CHR70C: http://www.creativesound.ca/details.php?model=CHR70C
MCM 4” aluminum cone woofers, 55-3853: http://www.mcmelectronics.com/produ...commendation&utm_source=prod&utm_term=55-3853
MCM 4” aluminum cone woofers, 55-1856
Dayton Audio DA115-8: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-328
Tang Band W4-656SC: http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-820&utm_source=Bazaarvoiceps


For tweeters:
Tang Band 25-302SH http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-804
MCM 1” titanium dome tweeters 53-1070: http://www.mcmelectronics.com/product/53-1070

I will be off and on in my ability to reply to this thread until next Sunday. Thanks in advance!

why I am so sure the woofers and tweeters are blown

If you are curious why I am so sure the woofers and tweeters are blown, it all goes back to a party in November. My daughter was having a birthday party and had the speakers hooked up to an amp in the garage and playing tunes from an iPod. My wife was mostly chaperoning and about the time the party was breaking up, I was called to the garage as “the speakers aren’t making noise and it smells funny.” I go outside to find the amp volume all the way up and not much noise. There was a strong electrical smoke smell, so I immediately started unplugging stuff. And trying not to get upset! The next morning, I hooked up other speakers to the amp and they worked fine but the minimus 7s, were not making any sound.

it's probably self-evident, but the easiest and most inexpensive solution is probably just to pick up another pair of Minimus 7s - they're almost frighteningly abundant.

Welcome to AK, by the way!

Yeah, with that amount of work, it doesn't make sense to find stuff that will fit in a minimus seven cabinet.
You should just make something from scratch at that point!

that was in the back of my mind: that perhaps I should just move on to something else

pauljas said:

that was in the back of my mind: that perhaps I should just move on to something else

Click to expand...

Or to another pair. Can be had for (very very) cheap if you are not in a hurry.

jancumps said:

Or to another pair. Can be had for (very very) cheap if you are not in a hurry.

Click to expand...

Totally agree. Picked mine up for around $7 at a yard sale. They turn up all the time on THE auction site and often on CL as well. Look up the Zilch mods, long thread but many good posts. I believe they stick with the original tweeter, which also show up. Many people love these speakers. I have a set, but not in rotation at the moment.

I have the Aura (out of stock, perhaps discontinued) version of
this driver to try in one of my pairs, there is an 8 ohm version also:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-212

However, I just never got around to doing a new crossover.
You can take the 4 screws out of the tweeter plate and the
guts should drop out, then you can consider a pair of these
tweeters to mount to the plate:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-1018

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-1002

The Minimus 7 was a copy of the Braun/ADS minis and used
lower quality drives. It is an interesting challenge to make them
as good or better.

Pete B said:

I have the Aura (out of stock, perhaps discontinued) version of
this driver to try in one of my pairs, there is an 8 ohm version also:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-212

Click to expand...

I notice that is more of a mid-range speaker. The options I posted are woofers. Should I be looking at options more in the mid-range?

Actually, while it is fairly good in the midrange it is actually a better bass
speaker than any you have mentioned. The Fs is low, Xmax is high. Look
at the size of the roll in fact I'm not sure that the grille will fit on with them.

And by the way, "Zilch's crossover" is a minor mod on the one I suggested
to him, lol:
http://www.audiokarma.org/forums/showpost.php?p=2355102&postcount=75

The P in PZ-2.1 refers to the fact that it is a minor mod on my PB-1 XO design,
in fact I suggested most of what he did as options. Lower woofer inductance,
smaller tweeter cap, adjusting tweeter R.

I have modded 2 pairs of Minimus 7w's. I used the Zilch crossover for one pair and the one on that auction site for the other. I like the Zilch pz 2.1 better.

I also replaced woofers and am very pleased witht the result. Here is the thread with my woofer mod and another member's woofer mod story: http://www.audiokarma.org/forums/showthread.php?t=366524.

I highly recommend doing this because it is fun and the results are excellent. The new woofers are much clearer and have better bass response to my ear (without measurements).

I have a tweeter problem in another pair I want to mod and am planning to try this tweeter if I don't buy one at auction: http://www.parts-express.com/pe/sho...m1010X497171X68d121f940c74d86b8fd484e7378a408.

Good luck with your project!

By the way, since I am a rookie, I will likely heed Pete B's advice and try the Vifa tweeter. Thanks, Pete B.

I do wonder if the driver changes are going to require changes to the PZ2.1 crossover. I wouldn't have a clue what to do then. As a result, I try to see if the specs on the replacements are close to the drivers being replaced.

Both tweeters are 3.2 ohm Re and I believe that the original was 6 from memory. You'd want to put 2-2.5 ohms in series with these new tweeters
to match the old network. Then adjust the input R to the tweeter network to match levels. I believe that these new tweeters will have enough sensitivity to have enough adjustment range with the input R.

Did you have a woofer in mind?

With everything blown, if you're attached to the look you could do better with the Minimus 11 or (which I'm guessing is much the same speaker), the Optimus 77. Old enough to be ready for their second refoam. I think that speakers with 5 1/4" woofers are just better speakers out of the gate. The next step up would be to a Minimus 25, somewhat larger wood cabinet than the Minimus 11, very much under the radar pricewise, and sporting one of my favorite cone tweeters.

I am using this woofer, andit is way more clean and clear sounding than the original:http://www.mcmelectronics.com/produ...commendation&utm_source=prod&utm_term=55-3853. It is not a drop in replacement, however because it is very deep. In modding the crossover, you have to be careful to put the inductor up a little higher in the box.

This is well worth it.

Pete, I am not sure how to do this as you say:

"Both tweeters are 3.2 ohm Re and I believe that the original was 6 from memory. You'd want to put 2-2.5 ohms in series with these new tweeters to match the old network. Then adjust the input R to the tweeter network to match levels."

Is there a tweeter that can be used without changing the PZ 2.1 crossover?

That woofer has a cast frame, does it clear the front grille?
Otherwise it looks fine but from memory I think it tested
worse (Zaph) than the cheaper MCM that I suggested - this
could certainly have been unit to unit differences.

I measured the stock Minimus 7 tweeter here, but not the
sensitivity:
http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=4679&view=findpost&p=76942

You want roughly the same Re, Fs and sensitivity if you are
not willing to test with an adjustable L-pad, then add fixed
resistors as needed. The Fs of about 2K is fairly high, but
there are probably some that come close. We are also limited
by the mounting clearances.

The $1 Audax looking tweeters sold here probably make the
most sense for a low cost replacement.
EDIT: I have a pair of these also and they are 8 ohm not 4 as
I previously stated:
http://apexjr.com/speakerstuff.html

This might work but is overpriced IMO, they were a bargain at
something like 5 bucks when they came out:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=275-030

The cast frame fits fine without any modification.

The price of the parts express is not so bad when compared to buying a used one at auction. I am more interested in which one would sound better.

Do you think the dayton would be better than this tang band? http://www.parts-express.com/pe/sho...m1010X497171X68d121f940c74d86b8fd484e7378a408.

There are a set of SD-72s on Ebay right now (8 ohms). I was actually looking at them for replacement tweeters for my Celestion Ditton 110s (trying to improve the sound). $16.99 apiece. Also those Tang Band tweeters can be had for much cheaper on Ebay ($36 per pair).

That TB has slight horn loading and I tend to try to use "like kind" drivers when looking for a drop in replacement. On the other hand you could modify the crossover to use it if it is a favorite - did Zaph test it?
http://www.zaphaudio.com/tweetermishmash/

More: http://www.zaphaudio.com/blog.html

The best sounding tweeter will have a smooth response, lowest distortion (especially odd products), and a clean CSD in my opinion. The small format tweeter that really stands out is the Vifa D26NC55, look at the plots at Zaph's site. Note that F4 and F5 are mostly below 90 dB with no odd peaks, F3 is mostly below 65 dB above 2K, F2 is not perfect, none of them are, but it is difficult to hear. Compare the distortion to the very expensive SEAS Millenium and for example SCAN 6600, 9500. I don't think the D26NC55 is available anymore but heard that Solen in Canada has some. Also, remember to weight your evaluation by how this tweeter is used, it is crossed over high and will not be driven hard since the system will run out of steam in the bass at fairly low levels.
Also note the Aura NT1-204 distortion, all but F2 are more than 70dB down over much of the operating range and it costs $15.9 at Madisound - this would be my choice for a more expensive Minimus 7 option. The dome is very delicate - you cannot touch it.
Zaph design with the Aura tweeter and MCM woofer:
http://www.zaphaudio.com/ZBM4.html

Zaph's tests are very good, however he does not hold the SPL constant when he does distortion tests so a driver with a falling low frequency response will show lower distortion than if the SPL had been held constant.

I could use some blown Minimus -7 tweeters for their mounting plates if anyone has a few. Mine are all good - don't have any to try other tweeters.