I think the more important question is if to use an asymmetric microphone array for classical piano. While it is certainly possible it is usually done at a bit of a distance, especially with directional microphones, to have a better blend of the instruments overall sound. Dependinding on the room's acoustics I would start at a distance of 1-2m. I would try to find a second MK4 or MK21 (which I personally prefer) capsule. Maybe the problem will not be the slightly asymmetric picture of the piano but the different amount of ambience captured by cardioid vs. subcardioid that might be distracting.
Of your mentioned pres I only know the Mackie. I think they are ok. I have recorded some CD productions with a Mackie 1202 and while they are not highend they are certainly usable.
Best regards
Hermann

gianlu5080 wrote: The weak component in my setup is preamplification: I could use the preamps on the Traveler, or my Mackie 1202 VLZ Pro, or Aphex 207 or finally M-Audio Duo (from what I read, the preamps on this unit are DMP3, but I'm not sure). Next year I'll upgrade to Millennia, but in the meantime that is all I have.

The Mackie sounds pretty good with the Schoeps. Before settling on the Millennia, please audition a DAV Electronics Broadhurst Gardens preamp.

I agree with both.

I have both the Millennia and the DAV and find them both useful under different situations. The DAV is certainly more affordable and frankly quite nice.

Many insult the Millennia's high frequency (especially lately, it seems quite popular to be down on gear which has been the mainstay for decades), however, I don't find this to be a problem at all for any of the schoeps line.

gianlu5080 wrote: Hi guys,
finally I made the jump and now I have two Schoeps (mk4 and mk21) for recording my next classical solo piano recital (Mozart, Chopin, Brahms, Wagner/Liszt). I'll try the NOS technique using the mk4 on treble and mk21 on bass.

I too would be greatly worried about using two asymmetric capsules in such a standard symmetric array such as NOS. (Hell, I'm even anal about using two unmatched caps of the same type!) I think the results might be kinda fishy.... You should do a lot of experimenting in advance at the venue.

No chance of finding a second MK21? A pair of those will be lovely for the big rep you are playing.

Best of luck,

Mike

Mike, I have been searching for a pair of MK21 for quite a long time. Finally I got two single capsules but it was really difficult to find them as people tend to keep those 8-) I love them too.
No problem with MK4. You can find these quite regularly.
Regards
Hermann

hughesmr wrote: [quote=gianlu5080]Hi guys,
finally I made the jump and now I have two Schoeps (mk4 and mk21) for recording my next classical solo piano recital (Mozart, Chopin, Brahms, Wagner/Liszt). I'll try the NOS technique using the mk4 on treble and mk21 on bass.

I too would be greatly worried about using two asymmetric capsules in such a standard symmetric array such as NOS. (Hell, I'm even anal about using two unmatched caps of the same type!) I think the results might be kinda fishy.... You should do a lot of experimenting in advance at the venue.

No chance of finding a second MK21? A pair of those will be lovely for the big rep you are playing.

Best of luck,

Mike

A friend of mine who was an assistant engineer for the RAI (Italian Radio Television) and recorded dozens of piano recitals suggested this combination to me, one mk4 directed to treble and one mk21 directed to bass in NOS array.
I'll try and then let you know (and possibly hear) the results.
For now I decided to go with Mackie pres, direct outs to the Motu Traveler and then recording two mono tracks in AudioDesk.
Or should I record one stereo track?
I've another doubt: do I need to pan the two microphones on the Mackie hard left and hard right or not with this technique?
I'm not an engineer so excuse me if I ask obvious questions.
Thank you

If you go directly out through the inserts of the Mackie you are pre fade and pre pan, that means, the signal is not influenced by fader and pan. Only if you want to listen to the monitor section of the mixer you have to pan left and right of course. If you use any of the other outs, these are post fader. Soundwise it would be best to use the insert out, because you bypass all the other sections of the mixer, resulting in the shortest possible signal path.
I would be very interested to hear the results of the recording!

Best regards
Hermann

I have used "mismatched" polar patterns to record piano. This can work well because there are so many valid perspectives from which to capture the instrument. It is not like reproducing an ensemble on a stage where there is an expected concrete image. Piano imaging can be more abstract, thereby permitting other competing recording characteristics to weigh in more. For example, trading off tight localization might buy you greater mood and tonality.

I have not used mismatched patterns in a near-coincident array, such as ORTF or NOS. Usually I have used mismatched patterns with coincident or spaced techniques.