Great Boccherini music! I teach in the Conservatorium in his native town and brings his name!

Studer, this is a fantastic performance that you captured quite beautifully. It really shows what a pair of mics that are well placed in a good acoustic can do.

What was the height and distance of your array on this? The (lute / archlute?) attacks in the pp passages are especially present and clear considering there are no spots.

Cm3 used as spots on strings in this recording.
Dpa 4006 with black grids as main pair
Joly modded nt5 on winds
Studio Projects cs1 on piano and solo cello

Quite a ways back...perhaps just on the edge of too much ambience (headphones tend to collapse the ambience and don't give a truthful picture on location...esp. closed back cans when monitoring in same room as the performers !)

About 3.5 m back from the front line of the performers, and 3 m high, with mic pair angled down to look at the tops of their heads (all were standing, apart from cellist) It was baroque guitar in fact, 6 string...small body (compared with modern guitar)

Very nice! What distance is the space on the stereo bar?

Thank you! The distance is 172 mm.

I apologise if this has been asked (and answered) here already….I’m using a CM3 as a mid mic in a mid-side pair, and am seeking advice on the location of the diaphragm within the cylindrical casing.

Is it located just underneath the perforated end cap….or behind the longitudinal vent-slots ? I’m assuming the same location applies to the CM4. I’d prefer no to open up my CM3 to investigate this, hence my question.

Thanks to J-P Gerard …if you could specify how many mm’s back from the perforated front edge the capsule face is located ?

I’m using it in conjunction with the sE VR2 active ribbon as side mic, and want to vertically-align the 2 ‘diaphragms’ as closely as possible…

When I held my CM3 to the light, I caught a glimpse of silver just at the top of the vents. Could be the edge of the suspension of the diaphragm...?

Don't know how deep the actual diaph. is behind the vents and I don't want to destroy one just to peek inside... but in practice a couple of mm won't matter so trust your gut feeling, should be about right. You can also do a simple phase check with a meter if you're so inclined but again - minutes differences here. Also, when pairing with a ribbon... you'll be in the ball park, since the ribbon dances around and the condenser diaph. doesn't move much so perfect phase alignment is basically impossible and the differences in size as well as the spacing between the transducers will have more impact than perfect alignment, if possible of the transducers. But, all this being said, as I recall, the CM3/4 grille is about 2mm thick then there's a small gap due to the capsule front spacers (factory fit, never open a CM3 or 4 as they may fall off and you'll probably lose them and the mic will be out of whack) then an air gap inside the capsule so maybe another 2 or 3mm so total 5mm from the front surface of the mic is not totally wrong.

Thank you for that detail J-P….given that the side vent slots begin about 6mm from the front edge of the mic barrel, the capsule face should be maybe about 2mm in front of the side slots ?

Possibly - this is all guess work! There shouldn't be much space between the back of the diaph. and the acoustic network for pattern control, indeed.

if it's any help, I did a rec with it and just presumed the front the capsule was where it picks up the sound, it worked well for me and didn't have any phase issues when rec in M/S. I don't have any photos of it but have a recording somewhere.