The short answer is this: it is important. Period.
Many studios post on their sites: "Beware of long lists of equipment!” like they know that this is he recipe for a bad recording. Sometimes it could be true, although very rarely, this should be more accurately worded as: "Beware of long list of crappy and cheap equipment!" What these studios don't tell you is how important the quality of the microphones, preamps and compressors is.
It is OK to advertise that the engineer’s experience counts for a lot, but if you ask for a certain high-end microphone for vocal or acoustic guitar that you know is part of your sound, and you're told that the studio has to rent one, it is only fair to assume that the engineer does not have the right experience to get the sound you’re looking for, because he doesn't work with quality equipment on a regular basis, so he doesn't know what can be achieved with it.
A common answer when you ask if the studio has some high-end microphones and mic preamps is that the studio gets a fantastic sound with an unknown brand, as they know really well how to use it. While that may be true (I still have to see that!!!) a good quality studio has to be able to offer you some options you can try and see which one provides the best results for you. And by options - especially for vocals- I mean large tube condensers with Neumann, AKG, Soundelux, Lawson, Brauner, Telefunken, Gefell, or Manley logos!
Always look for boutique quality and high-end/esoteric gear. The most important things are the microphones (look for names like Neumann, Telefunken, AKG, AEA, Lawson, Royer, Soundelux, Earthworks, Brauner, Sanken, DPA, Schoepps, Geffel), mic preamps and EQ's (like Martech, Neve, Millenia, Massenburg, Great River, Pendulum Audio, SSL, Chandler, Focusrite Red, API, Vintech, Tree Audio, etc), and compressors (Thermionic, Elysia, Tube Tech CL-1B, LA-2A, Portico Neve MBP, Avalon, 1176, Distressor, Cranesong, Manley, SSL, API, Shadow Hill, etc).
Do your homework and write down what the studio has to offer - microphones, preamps, EQs and compressors - and then do some research on the internet, there are many forums with a lot of info, like www.gearspace.com (where recording/mixing/mastering legends like George Massenburg and Bob Katz are moderators).
Understand that the performance of a single microphone preamp worth double the price of a 16 channels Mackie or Soundcraft mixer is beyond comparison with the Mackie! Many engineers use a compressor when recording vocals, but no compressor comes close to the TubeTech CL-1B or LA-2A for vocal work! The best engineer with the best equipment for the money you can afford - this is what you have to look for!
As I pointed out already, the performance is the most important element in the recording process. The sound quality comes mostly from the musician’s ability to interpret his part. Equipment will never replace that. But good quality equipment captures the sound properly and gives the engineer the raw materials for a proper mix and master. In other words, a poor performance or a poorly captured performance can only be masked to a certain extent in the mixing/mastering process. You want to set yourself up for sonic success from the get-go, rather than relying on post-performance trickery.
Always look for boutique quality and high-end and esoteric gear. The most important things are the microphones (look for names like Neumann, Telefunken, AKG, AEA, Lawson, Royer, Soundelux, Earthworks, Brauner, Sanken, DPA, Schoepps, Geffel), mic preamps and EQ's (like Martech, Neve, Millenia, Massenburg, Great River, Pendulum Audio, SSL, Chandler, Focusrite Red, API, Vintech, Tree Audio, etc), and compressors (Thermionic, Elysia, Tube Tech CL-1B, LA-2A, Portico Neve MBP, Avalon, 1176, Distressor, Cranesong, Manley, SSL, API, Shadow Hill, etc).
Do your homework and write down what the studio has to offer - microphones, preamps, EQs and compressors - and then do some research on the internet, there are many forums with a lot of info, like www.gearspace.com (where recording/mixing/mastering legends like George Massenburg and Bob Katz are moderators).
For a solo act, a good quality microphone might be sufficient by itself. But for a band, you want to have access to different microphone flavours, because if you overdub everything, even with a premium microphone, the final product will sound flat. A good quality studio must have a good collection of microphones, because each style of music and each instrument requires a certain sound and, there is no one type of microphone that fits them all.
If you want to record a concert piano, a matched pair of omni - Earthworks or DPAs - and a large premium condenser are the way to go, especially for classical music and jazz. Of course, two Rodes or AT will do the job, but YOU WILL HEAR THE DIFFERENCE! For reeds nothing beats a good ribbon mic. And staples like Royer R121, Coles 4038, AKG 414’s and 112D, Shure SM7, SM 57, SM 58, Electro-Voice RE-20 and MD 421 Sennheiser are a good bet for drums, percussion, bass, and guitars. While the most important thing for getting a top-quality product is the artist performance, the studio has to be able to provide the right tools to capture that sound.
Regarding the preamps: make sure the studio has premium preamps, which are suitable for the style of music you are playing. If you’re a classical musician, or for acoustic instruments, a transparent preamp like Millenia or Earthworks is desirable; for rock, jazz and R&B preamps like Neve, Tree Audio, Chandler, Focusrite Red, Martech, API, Pendulum Audio, Great River, SSL, Fearn, Vintech, Avalon are great options. There’s a reason the Millennia preamp is used almost exclusively all over the world for classical/chamber/choir music, where "clean" and "headroom" are the name of the game.
Of course, great preamps are not cheap. They do cost thousands of dollars! In your studio search you will be told how great Presonus, ART, Mackie and Behringer preamps are. Here is the news: they’re not! They're not bad, they’ll get the job done, but you can’t really compare a 2000 € one channel preamp with an 800 € eight channel preamp or mixer! Look for a studio that has a couple of great different preamps, so you can take advantage and get the best in different recording situations! API, Focusrite Red, Neve or SSL are great for drums; on the other hand, when it comes to record or warm up a synth, a tube preamp like Pendulum, Thermionic or Fearn is a great way to go.
You can skip this paragraph, it’s going to be a little technical, but it gives you a better understanding of why a microphone preamp does a good job. Most everyone knows that we have to avoid clipping during recording; what is not widely known is that, long before clipping, many preamps exhibit an extreme distortion increase, as they change from Class A to Class AB operation. Therefore, it is very important to have at least 6 dB between the peak level of the music and the clipping point to avoid a harsh sound. The difference between the average level of the sound and the clipping point is known as headroom. The bigger the headroom, the better the sound! The high-end preamps have clipping points as high as 37 dBu (+55 Volts), while the semi-pro and consumer equipment have 20 to 24. Simply put, in order to get a good sound, the preamps must have very high output devices and high-voltage power supply, which is very expensive; you won’t get that with 100 dollars per channel preamp. These cheap preamps are good for the hobbyist recording engineer, but they are to be avoided if you are looking for quality! The good preamps or EQ include very high-quality circuits and excellent transformers, and when you have to mic many tracks, you’ll understand it!
Pay attention to the vocal chain- make sure there is a great vocal compressor like Tube Tech CL-1B or the LA-2A, eventually a Cranesong Trakker. They do a great job without compromising the voice quality and, when used properly, you can’t tell that the voice was compressed – they’ve got a magic touch. Great vocal preamps are Martech MSS-10 (very deep, great for huge voices, huge headroom, many consider this to be the Ferrari of the vocal preamp world), Neve 1073, API, Pendulum Audio, Pacifica, Telefunken V72, Hardy, Chandler. As far as the vocal microphone, you want to be able to choose from a selection of great microphones to see which one fits your voice best and make sure you are given to try at least one high-end tube large condenser.
Always ask about the quality of the A/D and D/A converters. If the studio uses tape, that's not relevant, but if the sound is recorded into a computer, the converters are the first thing you want to look at! There are audio cards with converters like Motu, Lexicon Omega, Digidesign Mbox-2 or Echo which provide a good sound; but when it comes to a great sound, with extremely reduced artifacts in the process of conversion from analog to digital for recording or digital to analog when listening, look for mastering grade converters- Prism, Mytek, Lynx, Lavry, Antelope. When the track count is high, you’ll hear clearly the difference! The mastering grade converters are way more expensive, and, again, there’s a reason why. These converters provide higher integrity to the sound and they employ very sophisticated jitter reduction technology. In simple words, they almost entirely preserve the quality of the sound during the conversion to digital or to analog.
Nowadays, almost all release-quality recordings include the use of hard disk recording and editing systems like ProTools, Nuendo/Cubase, or Sequoia. Few people know that in a tape-based studio at least 20% of your time is spent waiting for the tapes to be rewound after every punch-in; this is not a problem in a random-access recording system like those mentioned above. Certainly, tape recording has its own advantages; a lot of people swear by the warmth of the sound. In fact, they bring to the table some distortion that is pleasant to the human ear. While digital recording at today’s resolution is very accurate, the sound of premium consoles with Neve, SSL, API or Harrison badge is famous, and you can hear it in all the major releases of pop/rock/jazz music. Unfortunately, they are extremely expensive, and you can find them only in the multimillion dollars large studios.
The hybrid analog/digital mixing systems gives a more personal and organic sound; that became possible due to the analog summing boxes. Some of them have a unique and beautiful sound: Chandler (made by EMI/Abbey Road), Inward Connection Mix690 (made by Steve Firlotte with the famous 690 Jim Hall op-amps), Fat Bustard (made by Thermionic), Great River MM20, Shadow Hills, Neve 8816, X-rack SSL. While still expensive, they are more affordable than the legendary consoles and there are medium and small studios that have started to use them; make note of studios using this approach – these boxes prove the studio has taken some pains to provide a high-quality final product.
As some of the studios ventured in the hybrid analog/digital mixing, check to see what hardware are they using along with their plugins: names like Eventide, Bricasti, Lexicon, TC Electronics for space/reverb/delays; Elysia, Neve 33609, Cranesong, Thermionic, 1176, SSL, API 2500, Retro Instruments, Avalon, Empirical Lab, Pendulum, Manley for compressors; and Neve, Massenburg, Chandler, Millenia, Elysia, Retro Instruments, Avalon, Pendulum, API, Weiss and Manley as EQ’s are quite desirable.
Another thing to look for are the plugins used. It helps if you see the UAD cards with plugins, or native plugins like Sonnox Oxford, Tone Projects, Acustica, DMG, Soundtoys, Fab Filter, Waves, SSL, Lexicon, Altiverb, Eventide, Relab, and so on… After many years of developing better and better algorithms, most of the plugins are excellent. Also, make sure the studio uses good software for voice editing - Melodyne, or Antares. Drums are usually a problem, and a tool for drum replacement like Drumagog, Trigger and even better- the trigger from Superior Drummer 3, can save the day!
Always ask to listen to some music (have some CDs with you) in the same vein with your music through the studio monitors. The monitors are used to judge the tracks, the mix and the mastering. If they're low quality, there will probably be a problem! The studio engineer is used to them and he can do an excellent good job, but there are situations when you will be asked to make some decisions, to accept or redo some tracks, and you may not be able to have an objective opinion! It helps if the studio has 2 or 3 sets of monitors of different makes and sizes, so you can check through all of them! It helps even more if the monitors are made by ATC, Barefoot, Focal, Klein & Hummel, PMC, Adams, KRK, etc - just ask to listen to your CD's and you will notice the difference! They reveal easy any problems and allow an engineer to achieve great balance and imaging.
There are many medium and small studios, and there is nothing wrong with them, especially if they pass the lower overhead costs to you (unlike big studios who can’t afford to do so, as they have a large overhead, due to personnel, rent and expensive maintenance). Just make sure they provide comfort, good acoustics and monitors and good equipment. Beware though: many people are recording with a computer, a cheap console or preamp and cheap microphones. My suggestion is to think twice before you pick the most inexpensive studio as your product will reflect that. A 200 € mic or preamp can’t provide the same quality you get from a 7000 € microphone or preamp (cheap mics made in China working exactly like Neumann is just plain marketing BS, you know they have to make money too! Not that they're terribly bad, they can be useful, but they’re very inconsistent). When you're putting a lot of effort into making a recording, saving one or two hundred dollars at the cost of low quality is a mistake.
In conclusion, always choose the studio that makes you more comfortable and meets your recording needs. What really make the difference are the engineer’s ears and experience, your musicianship, the space you record in and the equipment that captures your performance.