I know I'm late getting to this, but its important for everyone considering custom montors or earplugs:
I'm a fully licensed Hearing Instrument Specialist, also known as an audioprosthologist in some areas. I make ear impressions all the time, and there's a few things you should know. First, its impossible to make a good impression of your own ear. Someone else needs to make it for you. Second, if the person making an impression of your ear isn't good at it, you risk more than a wasted impression; most likely your eardurm will be completely ruptured, and you'll never hear out of that ear again, short of getting a cochlear implant (which is about as fun to have as it sounds).
So, you really need to go to a professional and have them make the mold. Steer clear of audiologists; not to knock them, but they really are trained at performing a wide array of diagnostic tests, and things like earmolds are secondary to them. They are almost always more expensive as well. Go see an HIS or auidoprosthologist like myself. They almost always have a few lines of in ear monitors they can sell, and they deal with signal processing whenever they're not making ear molds. We know what you want in a sound system that fits in your head.
If you're insanely lucky, you might get an HIS like myself who plays bass and already has monitors. Or you can always take a little trip to see me personally
