My keyboard setup is quite basic: I have a few MIDI controllers/keyboards, a few sound modules, and a modest audio setup.
Let's begin with the controllers, these are keyboards with no onboard sounds and must be connected to sound modules in order to generate music. I have three: an 88-key fully weighted, 76-key semi-weighted, and a 45 key unweighted controller.
For most, I would think an 88-key weighted and 76-key semi-weighted are musts. The MIDI outputs of the controllers run through an M-Audio MIDISport 2x2 USB interface which allows me to sequence or route the MIDI directly to the sound modules. These days I am running Apple's Logic Studio on a 2.4GHz Intel Core 2 Duo iMac.
The nice thing about always keeping the sound modules separate from the controllers, is that one can upgrade quite easily. For sound modules, I've stuck with Kurzweil and Roland. Kurzweil gives you the best piano samples in a box known to mankind (well, to me at least) and Roland gives you the best of everything else. My Kurzweil modules include the newer PC2R which is an improvement over my mid-90's era Kurzweil MicroPiano.
For my Roland module, I have a JV-1080 (64
note polyphony, multitimbral; upgraded from my original JV-880) with the
JV80-06 SuperSound Set, the JV80-09 Session, and the JV80-07 Keyboard of
the 60's and 70's expansion boards.
Since the venerable JV-1080, Roland has come out with the JV-2080,
XV-3080, and XV-5080 modules; the latter two offer more voice polyphony
and richer samples. But I'm still tickled silly over my 1080 and they
can be had quite cheap used. Nowadays everything can be done on the
computer with software based samples. I like my older system, though,
and it's great for live stuff without the computer.
The other essential component of a synth studio is the audio. Traditionally, one has a bunch of analog audio outputs from your sound modules that need to be "mixed" and sent to a amplification system so you can actually hear what you are playing. Of course these days one can stay all digital, but I haven't gone there yet. The image at left was what my studio looked like circa late 1990s.
The StudioMaster 8 channel mixer has large-throw gain sliders and 3 band EQ per channel with 2 effects sends (pre and post). I like it alot since it's pretty basic and large, simple, and clean. All the audio components (sound modules to mixer, mixer to amplifier, etc.) are connected with 1/4" XLR cables which are all of the heavy-duty Excelline variety and some recently added Monster StudioLinks.
The two audio outputs of the mixer run to a Samson Servo 150 Amp and Tannoy PBM-6.5II speakers connected with 12-guage insulated speaker cables (i.e, get the best cables you can afford). I also have a portable Barbetta Sona 32C (165 bi-amped Watts through a 15" woofer and a 7" horn). Unbalanced left-right outputs go to the M-Audio Firewire 410 audio recording interface at 24-bit/96kHz. This allows me to record on my iMac. Back in 2008, I upgraded my software synthesizers to Garitan's Authorized Steinway Virtual Concert Grand, and I do a mix of software-based piano and hardware (PC2R).
The effects send on the mixer goes into an ART Tube MP, which I use as a microphone pre-amp for vocals or my Matador Bongos or other percussion sound makers. For mics, I have a Shure SM57 and SM58 and an AKG Perception 220. I use an Alesis Nanoverb effects processor and an Alesis 3630 Compressor/Limiter to compress vocals, percussion, and when my wife plays her electric bass (which is almost never). All my gear was moved from basic black racks and tube stands to an Omnirax SynthRax 88 when we moved to our new house and I moved my gear out of the basement. It's a 3-tier cabinet with 3 sliding shelves and 30 rack spaces below and sports a custom Mahogany laminate finish that fits in with the rest of my home decor. We have a smattering of other music makers, including a Yamaha FG-411 acoustic guitar and a Dean Mark IV electric bass, both of which I am fooling around with.