Don't build a small room for big voices! You will be setting yourself up for dissapointment.

You may have to invest in some treatment for the large room, but the folks (Rod et al) at the acoustic treatment forum may be of some greater assistance. Bass traps or other standing mode type absorbers might be necessary. Some are not permanent installations. With wooden floors you might just get a very recital hall type sound and it could be very useable in post production.

If it were me, I would consider 3 mics. 1 for the close work and 2 mics for stereo techniques (probably omni) for natural acoutsics. The three working together with proper placement could give you excellent results. Let us know you budget and we can suggest some. Although I like the Rode mics, I don't think you would be satisfied with that one. For the stereo pair, I love the versatility and options offered by the AKG 414 B/ULS, and they can be used in either capacity. Schoeps would also be an excellent choice, and the people in the acoustic music forum might be able to help even more. Good Luck

Having done precisely what you are planning on doing for several years, and with a wife who is an opera singer, I give you some of what I know:

Most times an opera singer wants a recording they will want it done in an acoustical hall with which they are familiar, and they will hire an accompanist and expect a very good, tuned piano. Typically they will book a church or an auditorium or a hall of some form. They typically know the good halls in the area and have an in with various churches or auditoriums. You, as the recording engineer, will show up on site with a minimum of equipment and record them. A typical recording session is about 3-4 hours. From the first note they sing while warming up you have about an hour to an hour and a half before they fall apart. The rooms also cost money so they will want you in and out of there relatively quickly. Budget an hour for set-up and a half hour for tear-down and that is a full day.

Do not plan on doing this in either of your current spaces. Instead, turn the small space into your editing room where you will chop up the various takes (they will sing 12 minute arias and want to re-take a verse or chorus or a riff in there without redoing the whole thing).

Singers are picky about a lot of things - the accompanist, the piano, the space (so they can hear their intonation) and the final recorded sound of their voice. Singers work very hard at perfecting certain frequencies in the formants of their voice. If these don't come through the way they think they should they get ancy. If you can't afford a $60k piano I wouldn't even think about using your own space. If you CAN afford a $60k piano then spend it on other equipment and still record out on-site.

Microphones - these are pretty important with opera singers. I'd go with a pair of omnis (Earthworks makes some reasonably priced ones) and perhaps a spot mic for the piano or the voice. I generally recorded 6 tracks with the aim of only keeping 2, but due to the circumstances I always wanted some flexibility. Unlike a studio band you don't get to fine tune the setup for an hour. Once they hit their first warmup note the clock starts ticking. Have everything ready to go and ask them to warm up in front of the mics - that's where you do your sound check and make any minor adjustments. Once they're warm you hit record and take what you can get.

Nika

Thank you for the advise

Thank you both for your input and for taking the time to answer my questions. I will go with the option of recording in the large room and editing in the small room.

The piano is not so much an issue since I will be using a sampled piano for my next project anyway. I am working on a cross over project that will be arranged by someone else and I just have to contribute the vocal track.

I am totally inexperienced in creating a pop sounding vocal track with an operatic voice, kind of like Boccelli even though his voice is rather small and made for recording.

I guess the room should not add to much character but the voice needs to retain the individual quality that makes close miking insufficient.

Any experience with this issue? Again, help is appreciated.
best wishes,
J.