This article will deal directly with some basic aspects of having two guitarists in a band - the problems, opportunities, styles and variations. Just as a guide, it will be more useful for guitarists with a year or two experience who are in a situation like mine, so for people with a lot of experience things I list will probably be elementary. Nevertheless...
To start off the article, lets look at some of the more traditional uses of two guitars in a band, used very often in rock and metal (just an example). A typical division in this case is rhythm and lead, with the guitarists usually sticking to their respective roles. Therefore, this divides a band into 2 main sections - rhythm, with drums providing the beat, bass filling in the low frequencies, and the rhythm guitar responsible for the relative mid-range of the final sound. That left the lead with vocals and the second guitar responsible for melodies and those chaotic solos hair metal became famous (and infamous) for. This traditional setup is very common, as I said, in metal and heavy rock of which Metallica and Soundgarden are the examples. Note, I only use them as an aid to getting my point across. And, it comes as no surprise, that this approach, apart from serving as an accompanying part for the lyrics, is also used to fill in sonic space while the lead guitarist captures teh audience for his
When you are starting a band, and have a role for two guitarists, there's a question you have to ask yourself - "What roles are you aiming at for these instruments. Do you aim to create textures? Do you intend to make your guitarists sound differently or blend these two instruments in?" From my experience it is a good idea to separate the two guitars, because then your rhythm section will stand out, but also your lead guitarist's masturbation exercises or scorching, wailing blues licks won't get lost in the mix. For example, your general settings could be similar, but rhythm would keep its gain at about 5, signal dry and use neck pickup, and lead have gain of about 7, use bridge pickup, drench the sound in reverb and have treble slightly up. Yet again, that's only one example of how you could achieve such an effect.
The sonic soundscape described above is because of different frequencies the instruments cater for. Which brings me to my next point. The Great Wall. Not of China, but of sound. Sum 41 achieved this effect in Fat Lip - the choruses in particular. Here, rhythm and lead are still prominent, but their role differs in that rhythm is doubled by lead, usually one octave higher. This helps to achieve a "full" sound, as some bands, although they have two or three or 4,000 guitarists still manage to sound like a ukulele player instead of a guitarist in a death metal band. Using a second guitar to harmonize the main riff or chord progression helps you "complete the picture".
So this brings me to the end of the first part of this article. In the next instalment I intend to expand on the info above, and write about writing and arranging the musical parts in your band's songs. Feel free to comment and criticize, as this is my first article and it is by no means perfect, but please keep it constructive.