Don't be an idiot.
OK. For starters, any good mastering studio is going to offer:
What mastering engineers really do is LISTEN. You've heard the songs a million times, and obsessed over every detail. We're hearing the songs fresh, on really high resolution speakers, in a room that's as acoustically perfect as we can make it, where we've been sitting every day for years. It's a very objective environment, and we have a very objective perspective on the music, hearing it for the first time. Coupled with experience, this leads us to (hopefully!) make good subjective decisions about what each song needs.
I've mixed my fair share of records, and with all of them, by the time I was done mixing, the LAST thing I was in any shape to do was master them. I never wanted to hear those songs again, let alone try and make them sound any better. A lot of times when I've heard things that people have self-mastered, it's one of two things: either they did way too much and made some drastic changes that messed up a perfectly good mix, or they didn't do enough, and the track sounds ok but doesn't really sound finished, or as good as it could.
Lots of records are being made in home/project studios, and I'm 100% in favor of that, but these can be potentially very compromised acoustic spaces, which makes mastering more important than ever. Some tracks need very little, others might need quite a bit, in either case it's essential to have an accurate monitoring environment to really KNOW.
I strive to make it as simple as possible. Just upload your mixes, let me know the song order, any specifics regarding fade ins/outs or song spacing, and any other notes/requests you might have. I'll send you the master, check it out and give me your thoughts. If it's perfect and you love it then you just give me money, if you don't totally love it just let me know what the issues are and I'll get it sorted. Most times revisions are minor...a little brighter/darker, more/less loudness, different spacing between songs. All of these are easily accommodated.
If for some reason the revisions AREN'T minor and you're unhappy with the overall direction of the master, don't freak out. This almost never happens, but very occasionally it does, and usually it's just a simple matter of communication and getting on the same page. I'm perfectly happy to start the mastering over from scratch and try a totally different approach if needed.
If you're totally new to mastering and don't have any idea what it's about, we take a collection of mixes and make sure that each one sounds as good as it can, AND ensure that they all work together as a cohesive whole. We make sure the mixes will translate on a wide variety of systems, from earbuds to audiophile speakers and everything in between. Typically this involves using equalization to smooth out any frequency imbalances, compression to 'glue' the mix elements together and enhance detail, and limiting to control peaks and increase overall loudness. We finesse the fade ins/outs and the transitions between songs so the record flows nicely. We put in the track ids, cd-text and ISRC codes and run a series of quality checks to ensure a master that is ready for duplication/distribution.
My job is already easy compared to yours. Mixing is hard!
I wrote an article for Sonic Scoop awhile back that covers some of the most common problem areas, you can read it here.
Generally...while we can sometimes work magic in mastering, you don't want to rely on mastering to fix a weak mix. Don't mix in a vacuum, test your mixes on a variety of systems and make sure you're happy with them.
Listen for the consistency of the sounds within the mix. For example, a mix where everything sounds a bit dull is easily fixed in mastering, a gentle boost of the high frequencies will bring everything up and it'll sound great. But a mix where everything sounds dull except for a really bright hihat or tambourine is a problem. If we boost the high end and make everything else sound nice, that tambourine will be super painful and annoying. And then no one's having any fun.
Listen closely for unintended distortion, and things like vocal tics, mouth noises, bad edits, etc. All that stuff tends to become more noticeable after mastering, especially bad edits. Fix those crossfades! Also watch out for digital clipping of any kind, whether it be at the A/D converters during tracking, plug ins during mixing, or at the master fader.
Sure. Maybe a track got left out of a mix by accident or you realize the vocal on one song is just way too loud and somehow it just wasn't apparent until after everything was mastered. Whatever it is. I get it. So a new mix is no problem, but please note that I have to charge for this, because...time. Most mixes go through the analog chain, it takes time to recall the settings and reprint the master. There may be noises that need to be fixed with RX, etc. Even with an all-digital master, the time adds up. If I could snap my fingers and magically just "run it again with the same settings" that would be terrific, but alas I'm without these superpowers.
I'm kind of soft about this because I've been in your shoes before and I want to help you out, but please ask first!
Sure, I'm happy to do a test master of one song for new clients.
No problem.
No, you (or your label) need to provide them. Go here for more info.
I can embed the codes into your DDP and/or wav files.
Of course! We're out in the country in Rhode Island, if you want to make the trek you're more than welcome to come hang out. We have two handsome cats and birds and trees and stuff.
I come from a very DIY background...most people I knew making cool music didn't have tons of money. It's always been important to me to keep my rate really affordable...mastering can make a big difference, and I'd rather be able to help more people than less. I love my job, I love helping people make their records sound as good as they can.
I'm pretty skinny but I still gotta eat.