I've found the perfect retrofit for the beloved Minimus 7: Tang Band W4-930SF.
Just got them from Madisound yesterday and the fit is perfect. Even the original terminals fit from the old woofer (which runs full range with the original crossover). I disconnected and taped the leads for the tweeters and closed everything back up. Slam dunk easy.
I've just dipped my toes in the full range water and the water is fine.
Just got them from Madisound yesterday and the fit is perfect. Even the original terminals fit from the old woofer (which runs full range with the original crossover). I disconnected and taped the leads for the tweeters and closed everything back up. Slam dunk easy.
I've just dipped my toes in the full range water and the water is fine. An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Don't everyone jump up at once.
I'll have you know that there are at least five (5) people who would be very excited to see this.
I'm just happy to have increased the perceived fidelity in my polite office system.
I'll have you know that there are at least five (5) people who would be very excited to see this.
I'm just happy to have increased the perceived fidelity in my polite office system.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Neat. I've got a pair of Minimus 7. Maybe I should try that sometime.
My bigger (?) problem is with a bunch of Optimus Pro X33AV. They look similar to the Minimus 7, but have little 3" woofers with a 0.75" tweeter. Most of them have fried tweeters and the voice coils scrape in the woofers. I'd love to find a decent full range replacement that could drop in easily. Cheap would be good, too.
My bigger (?) problem is with a bunch of Optimus Pro X33AV. They look similar to the Minimus 7, but have little 3" woofers with a 0.75" tweeter. Most of them have fried tweeters and the voice coils scrape in the woofers. I'd love to find a decent full range replacement that could drop in easily. Cheap would be good, too.
TWEETERS
In my move last year I found a few pairs of a Sonance tweeter
which is an exact fit to the tweeters in the Minimus 7 system.
Here's a blog with a customer using them;
The Stereo Club: Apex Jr.: Your Source for Affordable Electronics
If anyones interested ... $15.00 pair
Steve @ Apex Jr.
In my move last year I found a few pairs of a Sonance tweeter
which is an exact fit to the tweeters in the Minimus 7 system.
Here's a blog with a customer using them;
The Stereo Club: Apex Jr.: Your Source for Affordable Electronics
If anyones interested ... $15.00 pair
Steve @ Apex Jr.
I'm using the original crossover (which has no filters for the woofer), but with the tweeters disconnected. I sealed off the crossover's tweeter leads with tape. I know it's cheap and dirty, but it was just too easy (and reversible).
Ty_, I just measured the dimensions of the original woofer mounted in the cabinet, and started hunting. After looking through all the full range options (3 and 4-inchers) in Parts Express (including all the discussions in the tech talk forum), I stumbled on this driver at Madisound after I read that PE and Madisound have different offerings from various manufacturers...
I'm willing to bet there is a full range driver that will fit yer little Optimi.
I actually had considered your tweeters, Steve. But I had to see what full range was like.
Ty_, I just measured the dimensions of the original woofer mounted in the cabinet, and started hunting. After looking through all the full range options (3 and 4-inchers) in Parts Express (including all the discussions in the tech talk forum), I stumbled on this driver at Madisound after I read that PE and Madisound have different offerings from various manufacturers...
I'm willing to bet there is a full range driver that will fit yer little Optimi.
I actually had considered your tweeters, Steve. But I had to see what full range was like.
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Off topic: Technics SL-1100A
Ah, another Technics SL-1100A owner/lover! I bought mine in 1976 at the US Army Post Exchange in Augsburg Germany Never needed anything else.
Tom.
Ah, another Technics SL-1100A owner/lover! I bought mine in 1976 at the US Army Post Exchange in Augsburg Germany
Never needed anything else.Tom.
Just found this. Nice! My beloved pair of Tannoy Dorset are beginning to suffer from terminal voice coil rub/suspension sag. Recone won't be cheap or easy, so I have to find a short term replacement. I have two pair of Minimus 7's, and was wondering if there's a fullrange driver that would fit... and here it is, on this forum as usual.
I did some quick n dirty modeling from TS parameters in a box response program. It looks like the Qts in this little metal box will be quite high, maybe 1.3. That would predict a bump in the response from around 150 to 350 Hz. Does your pair sound like that?
Anyway, I bought a pair, will be getting them Tuesday. I'm looking forward to hearing them.
Question --- In this tiny cabinet, is there a way to relieve some of that bump in the response by tuning with a port? I was thinking of removing the tweeter, making a plate to cover that area, and fitting a port to that plate. Using a freebie ported box calculator, tuning the enclosure to 70 Hz (which is the published Fs of the driver), I'll need a tiny 1/4" round port only about 1/4" deep. My goal is not to get the system to play bass, it's more to smooth out the low end in preparation for adding a subwoofer.
Hey von.h... Are you still using those Tang Band's in the Minimus 7 cabs? Have you made any changes? Did you find the response to have a noticeable bump in the low mids?
-=|=-
I did some quick n dirty modeling from TS parameters in a box response program. It looks like the Qts in this little metal box will be quite high, maybe 1.3. That would predict a bump in the response from around 150 to 350 Hz. Does your pair sound like that?
Anyway, I bought a pair, will be getting them Tuesday. I'm looking forward to hearing them.
Question --- In this tiny cabinet, is there a way to relieve some of that bump in the response by tuning with a port? I was thinking of removing the tweeter, making a plate to cover that area, and fitting a port to that plate. Using a freebie ported box calculator, tuning the enclosure to 70 Hz (which is the published Fs of the driver), I'll need a tiny 1/4" round port only about 1/4" deep. My goal is not to get the system to play bass, it's more to smooth out the low end in preparation for adding a subwoofer.
Hey von.h... Are you still using those Tang Band's in the Minimus 7 cabs? Have you made any changes? Did you find the response to have a noticeable bump in the low mids?
-=|=-
Most of the M7 1218 woofers I measured have an Fs~49Hz and Qts~0.31 (check out their hefty magnet!). Both a low Fs and Qts is the way to get away with a small sealed box. These TB will definitely sound different in there. The normal M7 Qtc is somewhat under 0.707 IIRC. The TB's might give the illusion of more bass if there is a bump in the response, but the original woofers will go deeper and be smoother.
M7 Vb ~1.8 liter IIRC. Makes sense if I sim that with the measured specs I have for 1218. An aperiodic vent will lower the Q, but there will now be no semblance of bass.
IG
M7 Vb ~1.8 liter IIRC. Makes sense if I sim that with the measured specs I have for 1218. An aperiodic vent will lower the Q, but there will now be no semblance of bass.
IG
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I was using them daily in my office until I started breaking in 4 EL70s (free-air) in their place a few weeks back. I recall seeing that high-Q when playing with WinISD... But my cabinets are actually the 'Optimus Pro7' which have a port in the back.
The port is ~3/4" diameter and ~2 5/8" deep, which nearly touches the back of the tweeter magnet...
The cabinet is 1.5-2 Liters.
I thought they sounded fantastic and well balanced from ~150 Hz up. While breaking in these EL70s, I've brought back the foobar Electri-Q EQ to dial them in to taste (roughly 3-5 db cut from 400 to 7k). The Minimus 930s were run without any EQ.
Note I use a 10" powered sub under my desk in this arrangement. So I haven't really cared about true bass response from these. I plan to return the 930s to the desk after I move ahead on building the Castle EL70 system.
The port is ~3/4" diameter and ~2 5/8" deep, which nearly touches the back of the tweeter magnet...
The cabinet is 1.5-2 Liters.
I thought they sounded fantastic and well balanced from ~150 Hz up. While breaking in these EL70s, I've brought back the foobar Electri-Q EQ to dial them in to taste (roughly 3-5 db cut from 400 to 7k). The Minimus 930s were run without any EQ.
An externally hosted image should be here but it was not working when we last tested it.
Note I use a 10" powered sub under my desk in this arrangement. So I haven't really cared about true bass response from these. I plan to return the 930s to the desk after I move ahead on building the Castle EL70 system.
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It wouldn't go as low, but a vented (or sealed) Alpair6M would fit that box (with better mids & top). Vent might need to be external thou if one aims for max bass.
dave
I assume you meant to write 'volume'...
Somebody wrote that the internal dimensions are (in inches) 7 x 4.5 x 4, which equals 126 in3, or about 2 liters. I got that number off the web, so can't vouch for its accuracy.
Would like to know more about aperiodic venting. Is that the one the old Dynaco A25 used, basically a port covered with acoustically absorptive material? Or is that the dual-chambered cabinet design, as in the old Dynaco A40?
With the Tang Band W4-930SF in such a tiny cabinet, I imagine I'm looking for a way to lower the Q from that of a sealed box.
- Ron
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Thanks, I missed your post at first, now I see it...
OK, 1.8 liters sounds more Realistic
. I'm not looking for bass much below 150 to 200 Hz from the M7+TangBand. My hope is to smooth out the low-end roll-off so I can couple these with a pair of woofers using only -6dB filtering without too much problem. I want to experiment with a simple RC x-over network at line level. Perhaps a -6dB hi-pass in the input of my homebrew PP-2A3 amp (6wpc, nice Tango OPTs) and a cathode-follower buffered, -12dB lo-pass to a woofer amp with volume control. I have a 110wpc Hafler MOSFET amp I can use for this, which is more sensitive than my 2A3 amp and has its own input level controls.
High volume and big bass are not as important to me as mid and high frequency purity. That's what I like about the PP-2A3 amp.
Once I've figured this setup out, I figure I might try a final version with Alpair CHR-70 drivers and proper cabinets. This M7-TangBand project is a sort of trial run.
thnx
Yea, when i was going to high school i was not going to need to know how to type, so took grade 11 math instead of Grade 10 typing.
Yes, fiberglass insulation and rain gutter mesh works well. Or a series of small holes with an appropriate open cel foam covering the holes on the inside. The former is more appropriate for the box we ar etalking about.
You don't want to start with too high a Q, 1.1, to 1.3 is likely a good maximum target.
I think i may try Fountek FR88ex in my spare set of M7 boxes.
dave
I found this freebie online calculator and plugged in the T/S parameters -- http://www.mh-audio.nl/CBC.asp.
Tang Band W4-930SF specsheet: https://www.madisound.com/store/manuals/w4-930sf.pdf
If I put in a 1.8 liter box, I get
Qtc = 1.135
Fc = 169 Hz
F3 = 127 Hz
it predicts a +2dB peak at 216 Hz.
Re: aperiodic loading -- Have to look up how to stuff the cab and how to calculate size of opening(s). It would be nice if one or two 3/8" or 1/2" round holes could work. I happen to have that size hole saw bit.
-=|=-
and then a little Googling yielded this:
http://www.diyaudio.com/forums/multi-way/162130-aperiodic-loading-lower-qt.html
!
http://www.diyaudio.com/forums/multi-way/162130-aperiodic-loading-lower-qt.html
!
Thanks, I missed your post at first, now I see it...
OK, 1.8 liters sounds more Realistic
hahaha REALISTIC....The irony....Just like the ads for 'Mr Muscle'(kitchen cleaner), featuring possibly the skinniest man alive.
I seem to remember the minimus range being sold when i was a child, in Tandy/RadioShack.
Almost ANYTHING should sound better than these did in original form........ I like the Alpair idea though...its a pity those Hivi or aura 3" are probably too small a frame size to fit.
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