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Minimus 7 Loudspeakers - Measurements

Questions about the M7 Measurements project

Zilch, et al,

I have a pair of 7w's (40-2039B) and a white-metal pair (40-2045), both pair MFG'd in Korea. Lucky $5 purchases at thrift stores. Still looking for more, especially the W's.

I've recently read this string and some of the others about the M7's. Kudos to all of you who have done such great work on these mods.

I have a few questions I hope you guys can help me with:

1. Does anyone sell the completed XO mod? If so, please PM me.

2. Was a fix determined for the edge diffraction problems noted in the thread? Some kind of foam or felt was mentioned as a possibility in the thread but I can't find the posts.

3. Is there a consensus opinion on stuffing (material, location(s), amount) the cabinets?

4. I'm looking for a small-footprint used powered-subwoofer to match with these. Is a cutoff of 150 Hz appropriate or would something higher be better?

5. Any plans to look at the Optimus Pro LX5 with the Linaeum tweeter? I've read the Stereophile review and info on the Larry VanWormer mods but replacing the drivers is more than I want to do/spend on thrift store finds.

Thanks.
 
1. None known, but if it caught on, we might do a PC Board for it.

2. No; ignored.

3. Not analyzed. The action's in the HF.

4. 150 Hz is fine. The answer I was looking for early on was 125 Hz.

5. No, but we've set the benchmark for others to do similarly.... :yes:
 
acalunas1 said:
Zilch, et al,

I have a pair of 7w's (40-2039B) and a white-metal pair (40-2045), both pair MFG'd in Korea. Lucky $5 purchases at thrift stores. Still looking for more, especially the W's.

I've recently read this string and some of the others about the M7's. Kudos to all of you who have done such great work on these mods.

I have a few questions I hope you guys can help me with:
~~~~~~~~~~~~~~Big Snip~~~~~~~~~~~~~~~~~

5. Any plans to look at the Optimus Pro LX5 with the Linaeum tweeter? I've read the Stereophile review and info on the Larry VanWormer mods but replacing the drivers is more than I want to do/spend on thrift store finds.

Thanks.
Click to expand...

Acalunus,

I've emailed back and forth with Larry over the years and he's told me that just the crossover mods (with the Dennis Murphy added resistor) and painting on a 5 spoke configured (one inch) stripes with Mod-Podge on the stock woofer is pretty darn good. The drivers that Eric Wallin used are no longer available, btw. I might add, that Larry used duct seal or oil-based modelling clay on the woofer's chassis as well as several "ridges" of the same on the inside of the cabinet walls for damping. Apply a cap of thick felt glued with Aleene's original tacky glue to cover the magnet as well as a felt lining to the inside of the woofer's spokes.

Best Regards,
TerryO
 
Zilch said:
Before:

attachment.php

After:

attachment.php
Click to expand...

Please excuse the noobish question, but can the after curve be approximated by EQ'ing? My pops gave me a set of the Pro7's (ported), and I'm curious to see if I can EQ out the bad spots in the response (using foobar2000) for nearfield desktop listening.
 
von.ah said:
Please excuse the noobish question, but can the after curve be approximated by EQ'ing? My pops gave me a set of the Pro7's (ported), and I'm curious to see if I can EQ out the bad spots in the response (using foobar2000) for nearfield desktop listening.
Click to expand...
Yes, but it'd take multiple parametric filters to accomplish what $15 per unit in passive components have achieved here.... :)
 
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juniorJBL said:
So what is this year's Holiday testing schedule? :D
Click to expand...
1) The SawZall will kiss another pair of AR4x, installing 8" PT waveguides in them, and a "mystery" woofer. Think AC18.

2) The AR3a Hi-Vi tweeter upgrade. I've been tripping over them for nearly a year now.

3) The indominable Presidians -- a couple more trials, then move 'em on out.

4) More eWave kerfutzing; I need to complete a mate for the one I've just built.

5) Whatever WiredGuy wants to do next, probably Boston A100s. We're all but done with his Jamos, which got Mindignia woofers; I've just got to measure and document them. Bose 301s we did as a joke, but they surprised us, so we're still thinking about those.... :dunno:
 
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Hello all! Long time listener, first time caller.
Up until now, the only thing I have successfully used is a can of deox-it. I am halfway through this mod, (have done one speaker) and words can't express my gratitude. I finally took the plunge and bought a new soldering iron in my package of goodies from PE. I christened this iron by burning the bejesus out of my thumb, while desoldering the second wire from the x-over. BTW, I can offer one tip, in exchange for all the glorious specs Zilch and Skywave have laid out. I learned this from a friend of mine who is a hibachi chef. If you happen to be as clumsy as I, and burn yourself, soak it immediately in soy sauce. It doesn't blister, and the pain is considerably less. Ok, enough OT. I picked my Minimus 7's up for 7 bucks, ironically enough. I have been using them with a super T amp and my ipod. I couldn't really figure out the wiring diagram, (I'm green like that) so, thank god (or Zilch) for all the pics. After completing the one, I found myself at an impasse, thanks to mis-typing my PE order. I only received one 3ohm resistor. So, all hopped up on coffee and new found success, I decided to take apart my t-amp. I upgraded the terminals to banana posts, and only burned 2 battery wires. F-it, I'll just use the power supply.
BTW, what would suffer by me leaving the 3ohm out for now? Would that be like a car with no 2nd gear?

Zilch, I am very much awaiting the sawzall and AR4x love connection! While researching the work on the Min 7's, I stumbled across the thread on E-waving the KLH model 17's. I have a pair with 2 bad speakers, sounds like a perfect fit. I got a chance to hear Kegger's *(I think) E-waves at the Fest, and they were outstanding.

In closing, I hope this hasn't been too much OT, I don't post very often, but It is always nice to know that there is such a wealth of knowledge in such a great cyber-community. Thanks to all and to all a good night!
 
If you can get 14 Minimus 7's (7 pairs) they make very nice line arrays. Suprisingly good imaging if a bit difficult to drive. :dunno:
 
budgophille said:
BTW, what would suffer by me leaving the 3ohm out for now? Would that be like a car with no 2nd gear?
Click to expand...
It's damping a peak in the woofer response near crossover, and will be audible.

Check your order. If PE shorted you one, they'll get it out to you immediately.... :yes:
 
Thanks, but I checked, it was my fault. I'll re-order, and I guess I'll have to wait until it gets here. Probably a dumb question, but with the upgraded x-over, does that reduce efficiency? One other thing, I burnt the outside of the 4.7 cap a little bit, would that affect the sound as well?
Thanks! Jon
 
Depends where you measure it. Look at the stock response curve in comparison to the modded one; we've considerably attenuated portions of the higher frequencies without affecting the lower ones in order to flatten the response. The spectrum is now better balanced, which could be perceived as having reduced efficiency, since the characteristic "forward" M7 sonic character has been mitigated.

While damage to the covering will not likely be a problem, I'd order a replacement cap.... :yes:
 
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Sir.Byrd said:
I have 15 pairs, I'm going for the gold here. :D
Click to expand...

Do it Sir, Do it!

Zilch said:
The spectrum is now better balanced, which could be perceived as having reduced efficiency, since the characteristic "forward" M7 sonic character has been mitigated.
Click to expand...

Gotcha. I was getting a little antsy as to what my t-amp would do for them. Hopefully a few mods to that, and everything will be peas and carrots. :thmbsp:
 
Post Xmas M7 find

Perservered in going to one last out-of-the-way SA store after making the rounds, rewarded by finding a box of 6 Silver-painted Japan-sourced M7's for $25. All 6 sound good, small mechanical problem with 2.

I have read several posts indicating that the Japan-sourced units are more desirable than the Korean-sourced units (my other two pair) because of the tweeter (Fostex?). Is this the case? Is there some kind of identification I should look for on the drivers?

Any tips on removing/reinstalling the metal grills? One could use a little bump work.

The buttons on the spring clips on two of the units stick when pushed in. I was planning to give them a little spritz of contact cleaner spray but thought I would ask first if that might goober up something inside. Any caveats and/or suggestions?

Thanks
 
I was just comparing my Minimus 7's to my 77's, and I noticed the only difference is a slightly larger enclosure and 5" woofer instead of a 4". The tweeter is the same, and the crossover is the same(although the components on the 77's look cheaper).

So, would the PZ-2.1 mod work on these as well? They seem to have very in your face upper-mids as well.:scratch2:
 
I encourage you to try it; you're $15 away from an answer many here would like to know.

[It's a collaborative.... :thmbsp: ]
 
That's all I needed to hear, and I'm happy to help out.:yes: I probably won't be able to get to this right away, I have a few more projects in front of this.:D
 
Pete B said:
I ordered some of the $1 Alesis crossovers shown here since they have
small bar type inductors. Note that the schematic shown there has
some incorrect values:
http://apexjr.com/speakerstuff.html

There are 1.1 mH, .52, .11 mH bar type inductors, and a .12 mH
air core.
2.2 and 4.0 uF mylar type caps, and a bunch of NP electrolytics.
The 1.1 mH should be fine for the 1.0 mH, and the mylar caps should
be close enough. The 6 and 7.5 ohm resistors in parallel are close
enough to the 3 ohm. The circuit board could be reused I'm sure.

It is a budget speaker, this is a good solution to keep the cost down.
Click to expand...

Pete, did you ever get these? Did they work out? I'm fixin' to pull the trigger on these for my powered M7's, and maybe a set for my M77's after that...
 
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