OK thanks to Allen B for image help.
Sadly do not understand totally the remaing posts.
Firstly the Caw 538 is long gone, Its plasticy sounding midrange as well as its dullness by comparison is the issue notwithstanding whether it is in an acceptable within range cabinet Q etc etc.
Specifications rarely give a clue to sonics. Not in my 60 years of experience.
To GM The resistance of the inductor .95mh is more than the 0.5R wiring ?
More important seems to be the use of a 2.7R in series with 5.6uf accross the woofer in addition to its normal second order xover parts. ie .95 and 10uf.
I would love someone technical to explain the reason for them..
Its slightly different values on the M71...
will try post of xover design mid only asap.
However the plan to replicate the Mission M71i into the Wilmlow Allegro is now into rethink three.
The cubic space above and behind the midrange box in addiution to the .3 cuft box is very nearly the same as the Mission M71i.
So it likes like 1st attempt is to drill out a hole in the minibox rear wall.
Then to seal off that back area along the bottom of that back caity. ie 150 x 160 ish.
If that doesnt sound sonically correct I will then
move on to a venting port for this volume. Direction to be decided later but internally sounds easy and neater? ps Using identical sized port from Mission. 71i..
Sorry Allan B but I will try another jpeg ..
Now if that fails ?? Cannot be tto far out. I
see also https://www.diyaudio.com/forums/mul...stion-tweaking-mission-m71-2.html#post6518020
Sadly do not understand totally the remaing posts.
Firstly the Caw 538 is long gone, Its plasticy sounding midrange as well as its dullness by comparison is the issue notwithstanding whether it is in an acceptable within range cabinet Q etc etc.
Specifications rarely give a clue to sonics. Not in my 60 years of experience.
To GM The resistance of the inductor .95mh is more than the 0.5R wiring ?
More important seems to be the use of a 2.7R in series with 5.6uf accross the woofer in addition to its normal second order xover parts. ie .95 and 10uf.
I would love someone technical to explain the reason for them..
Its slightly different values on the M71...
will try post of xover design mid only asap.
However the plan to replicate the Mission M71i into the Wilmlow Allegro is now into rethink three.
The cubic space above and behind the midrange box in addiution to the .3 cuft box is very nearly the same as the Mission M71i.
So it likes like 1st attempt is to drill out a hole in the minibox rear wall.
Then to seal off that back area along the bottom of that back caity. ie 150 x 160 ish.
If that doesnt sound sonically correct I will then
move on to a venting port for this volume. Direction to be decided later but internally sounds easy and neater? ps Using identical sized port from Mission. 71i..
Sorry Allan B but I will try another jpeg ..
Now if that fails ?? Cannot be tto far out. I
see also https://www.diyaudio.com/forums/mul...stion-tweaking-mission-m71-2.html#post6518020
I can imagine what you're describing, but look forward to you confirming later with a schematic.
The second order filter is entirely dependent on its load to operate as expected around resonance. The woofer is that load, yet it doesn't present as a simple one, instead it varies with frequency.
If you are going to redesign later it might be possible to make it work without those extra components, worth a try then.
mission m71i
Hi Dave That looks exactly as I recall and I was just about to open up them.
Note Woofers are Mission units not caw 538 They went long ago.
Value of x = 10uf and y = . 20mh inductor.... also resistor 2.2R changed to 3.3R better balance..
even colo(u)r of speaker correct.
😕
Currently they sound better with tweeter above. Go down a long way..Image well.
Thats how they will be in Allegro cabinet. \note That is sloping backwards slightly/
Hi Dave That looks exactly as I recall and I was just about to open up them.
Note Woofers are Mission units not caw 538 They went long ago.
Value of x = 10uf and y = . 20mh inductor.... also resistor 2.2R changed to 3.3R better balance..
even colo(u)r of speaker correct.
😕
Currently they sound better with tweeter above. Go down a long way..Image well.
Thats how they will be in Allegro cabinet. \note That is sloping backwards slightly/
slow progress
Dave Thanks for update but due to reaction I have been laid low, so only listening for last few days.
Comments so far. The fact that the 5.6 and 2.7r go accross the woofer I consider must have an effect on its performance sonically. 4 parts versus two.
Actually its 5 parts as |I bypassed 5.6 with HQ 0.01 pp caps to obtain a better result.
After installing the two 10uf caps I noticed an even greater result. Elcaps v PP. Bass more controlled and more detailed,
It occurred to me that the 2 x 5.6 maybe are only polyester ? ie slightly blander sonics, so Ive just ordered Polyprop replacements. I could do with a slight improvement in dynamics.Will report if anything observed.
Looking through threas I have noticed the Mk 1 version seems to have had a 5.0uf and 2.2R resistor in series, A reviewer somewhere states this was to improve the midrange...How?..
Currently leaving things alone due to fuzzy vision.
Dave Thanks for update but due to reaction I have been laid low, so only listening for last few days.
Comments so far. The fact that the 5.6 and 2.7r go accross the woofer I consider must have an effect on its performance sonically. 4 parts versus two.
Actually its 5 parts as |I bypassed 5.6 with HQ 0.01 pp caps to obtain a better result.
After installing the two 10uf caps I noticed an even greater result. Elcaps v PP. Bass more controlled and more detailed,
It occurred to me that the 2 x 5.6 maybe are only polyester ? ie slightly blander sonics, so Ive just ordered Polyprop replacements. I could do with a slight improvement in dynamics.Will report if anything observed.
Looking through threas I have noticed the Mk 1 version seems to have had a 5.0uf and 2.2R resistor in series, A reviewer somewhere states this was to improve the midrange...How?..
Currently leaving things alone due to fuzzy vision.
This is handy if you have a high Q wideband driver (e.g. something from a guitar amp or TV) that you want to use as a mid (in a conventional cabinet).
Putting such a driver into a small stuffed tube that is open to the rear of the speaker cabinet gives a smooth rolloff and smooth impedance, allowing for a minimalist crossover, or no crossover.
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If you want to judge something, make it the end response, and not the way it is achieved. In this case that is more relevant.
You are hearing a change in response around the driver resonance. This is more relevant than the type of capacitor.
I also had my mid in a small closed box,
now my mid is in a much bigger aperiodic vented box.
The mid cabinets went from a 3.5 liter closed box in v1 to a 10 liter aperiodic vented cone shaped box in version 2,
this made a huge update to the sound:
with the small closed box in v1 I didn't get the Accutons C173-6-090 to sound completely good, sometimes it sounded nasal, congested,
I suspect it was due to the backwaves of the cone bouncing around in the small closed box.
With the new 10 liter cone shape tapered box (45cm long), the backwave is completely absorbed, also thanks to the very good Twaron Angelhair (stuffed 3gr/l)
Now it sounds much more natural, open and dynamic.
Inspiration for the larger cone shaped mid comes from Troels,
the venturi vent in the Avalon clone and the XTZ divine.
My findings correspond to Troels ones, see halfway "Mid cab vent"
Almost all of Troels mids use a vented box.
now my mid is in a much bigger aperiodic vented box.
The mid cabinets went from a 3.5 liter closed box in v1 to a 10 liter aperiodic vented cone shaped box in version 2,
this made a huge update to the sound:
with the small closed box in v1 I didn't get the Accutons C173-6-090 to sound completely good, sometimes it sounded nasal, congested,
I suspect it was due to the backwaves of the cone bouncing around in the small closed box.
With the new 10 liter cone shape tapered box (45cm long), the backwave is completely absorbed, also thanks to the very good Twaron Angelhair (stuffed 3gr/l)
Now it sounds much more natural, open and dynamic.
Inspiration for the larger cone shaped mid comes from Troels,
the venturi vent in the Avalon clone and the XTZ divine.
My findings correspond to Troels ones, see halfway "Mid cab vent"
Almost all of Troels mids use a vented box.
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after long delay I am back after playing around
Well whatever the reasons that cause a change in sonics ? I removed the the Mission Midranges and inserted into my Wilmslow Audio cabinets with a bit of work involved. In order to maximise similarity with original Mission cabinets I also created rear ports from said Mission 71i and proceeded to listen minus Volt woofers. OK this may be considered messing about but I also left my Morel 32 tweeters in.
Using Missions now upgraded crossovers the initial results were interesting.
So basically I sealed off the excess cubic space in the Allegros and listened with rear ported vent. ie missions with a bigger front surface. Surprised how low theses went but slightlly obvious compression and blandness compared with Mission original. I tried tweaking the tweeter level next .
Eventually I removed the partitioning/ sealing of the upper half of the cabinet and tried listening to that for a while using upper rear vent .
Next I changed the porting to original Allegro longer tubed front and sealed rear shorter mission vent
and used the longer front vent. After a while getting used to the slightly boomier plummer vocals (softer tone but poorer imaging than I had achieved on original Missions) I then tried removing the 5.7uf /2.7 R accross the midrange. I soon replaced them as sonics were weird , pressumably this unbalances the impedences of mid against tweeter.
So , all in all , it has been a slow learning experience and some fun but I do not feel further experimentation or making it a three way will be beneficial, I definitly miss the openness of the Volt units with my own design tweeter xover. I also like the smoothness of those mission midrange but not their bass performance despite them going deepish.
I shall restore the Missions to my best performance status and add a subwoofer which is almost certainly the way to go apart from component improvement. Also improved rear speaker connections from brass to copper type. Well worthwhile as I had already soldered accross the inputs both red and the black . Ok this makes reversing the phase or birewiring out of the question or a lot more difficult. Reversal of phase did not seem worthwhile but that test was done very early on. It is a totally different animal now.
Only real benefit of this posting is to stop people messing around with units mentioned. Dave
Well whatever the reasons that cause a change in sonics ? I removed the the Mission Midranges and inserted into my Wilmslow Audio cabinets with a bit of work involved. In order to maximise similarity with original Mission cabinets I also created rear ports from said Mission 71i and proceeded to listen minus Volt woofers. OK this may be considered messing about but I also left my Morel 32 tweeters in.
Using Missions now upgraded crossovers the initial results were interesting.
So basically I sealed off the excess cubic space in the Allegros and listened with rear ported vent. ie missions with a bigger front surface. Surprised how low theses went but slightlly obvious compression and blandness compared with Mission original. I tried tweaking the tweeter level next .
Eventually I removed the partitioning/ sealing of the upper half of the cabinet and tried listening to that for a while using upper rear vent .
Next I changed the porting to original Allegro longer tubed front and sealed rear shorter mission vent
and used the longer front vent. After a while getting used to the slightly boomier plummer vocals (softer tone but poorer imaging than I had achieved on original Missions) I then tried removing the 5.7uf /2.7 R accross the midrange. I soon replaced them as sonics were weird , pressumably this unbalances the impedences of mid against tweeter.
So , all in all , it has been a slow learning experience and some fun but I do not feel further experimentation or making it a three way will be beneficial, I definitly miss the openness of the Volt units with my own design tweeter xover. I also like the smoothness of those mission midrange but not their bass performance despite them going deepish.
I shall restore the Missions to my best performance status and add a subwoofer which is almost certainly the way to go apart from component improvement. Also improved rear speaker connections from brass to copper type. Well worthwhile as I had already soldered accross the inputs both red and the black . Ok this makes reversing the phase or birewiring out of the question or a lot more difficult. Reversal of phase did not seem worthwhile but that test was done very early on. It is a totally different animal now.
Only real benefit of this posting is to stop people messing around with units mentioned. Dave
I just opened my M71.
Looking at the crossover board and the schematics above, I find some discrepancies, as such:
The high-pass filter is 3rd order filter;
2R2---5uF(MKT)---L connection---10uF(NPE)--- Tweeter
I can post a pic of the board, if needed..
I plan to update, still not sure why the MKT is in front of NPE....
Thx
Looking at the crossover board and the schematics above, I find some discrepancies, as such:
The high-pass filter is 3rd order filter;
2R2---5uF(MKT)---L connection---10uF(NPE)--- Tweeter
I can post a pic of the board, if needed..
I plan to update, still not sure why the MKT is in front of NPE....
Thx
Often the larger value is closer to the driver with a 3rd order filter. Often larger values are electrolytic for practical reasons.
Just swap C1 & C3 for fresh lythics if the loudspeakers are 25/30 yo. Nichicon is making good NPE radial lythics for loudspeakers.
The MKT is perfectly fine and anyway is before the next cap to the twweeter.
The MKT is perfectly fine and anyway is before the next cap to the twweeter.
