Well, now that I've reeled you in with my scientific title, I'm going to bore you with another article. This is a 2 part-er where I'm going to analyze the production techniques and the equipment that went into recording (and the subsequent live playing of) the songs.
The "Fire Sound" you hear on the album is mostly edge-of-chaos-and-bursting-into-feedback Marshall JCM800s being played through with Teppei's baritone Jaguar, Dustin's old Variax Tele tuned low and Eddie's 5 string basses. Yes, even the bass was given the cranked Marshall overdrive treatment. There's a picture from Thrice's blog from the Fire jam sessions below that shows Eddie playing a Fender 5-string with humbuckers that I've never seen before.
Effects-wise, this EP is the most stripped down except for the Earth disc. The sound you hear is mostly just cranked amps, sometimes with reverb added in the production. Backdraft's verses are an exception. They feature low tuned, slightly dissonant acoustic guitar. Clearly though, they were produced to be fiery. The guitars are distinctly less pure, and this can be achieved by overloading the microphone during recording. This may have been what Thrice did, or the guitar may have been tinkered with by adding overdrive/boost in production. Either way, it's been EQ'd to Hell and back, boosting the mids for less clarity and more of a "guitar cutting through the flames" sound.
If you want this sound for yourself, but don't have the cash for a Marshall JCM800 there is a pedal that comes close to the fiery goodness: the Crunch Box by M.I. Audio. A guitar that isn't voiced too modern will give you a definitely fiery tone when combined with a cranked Crunch Box.
The Water sound is a bit harder to obtain, as each song uses various modulation effects to add ambiance and make the recording, well, wet. Even the vocals contain effects, like the vocoder in Digital Sea. Each instrument is filled with delay, and reverb was added to everything later on. The delay adds an open, spacy feel. It takes your guitar from the land to the seashore where the waves are crashing. This almost gets you the water sound, but your tone doesn't really dive in until it's drenched in flanger/phaser.
The flanging can be heard in the background in Night Diving, and that ambience would be pretty impossible to recreate live. The clean guitar tone can be though. There's definitely a bit of chorus on top of the delay and reverb. Phasing or flanging (depending on the song) add the wet "warble" to the tone, and can be picked out through listening pretty easily. Teppei may have used his Line 6 Filter Modeler on the recording, too. The "drowning" sounds (listen to the end of Night Diving) are another production technique where the EQ is tinkered with, pretty much just leaving the mid-frequencies. This is another thing that can't really be duplicated live.
The overdriven tones (Night Diving's main riff) can be achieved most easily through a single-coil equipped guitar with a bit of delay added. The tones aren't nearly as close-to-the-edge as on the fire album, and can be achieved with something rich in mids, like a Tube Screamer (or a Digitech Bad Monkey for a really good, wallet friendly alternative). The guitars on the recording are drenched in reverb, but generally using reverb in a live situation is a no-no. The delay will help get you that ambience. If there's one pedal essential to the Thrice tone from Vheissu onward besides gain pedals, it's delay.
For the modulation tones, I recommend an Electro-Harmonix Deluxe Electric Mistress (avoid the Stereo model) for flange and an Electro-Harmonix Nano Small Stone (avoid the non-Nano models, as they have a volume drop) or an MXR '74 Script Phase 90 reissue (avoid the block logo models) for phasing. You'll also need an amp with strong clean tones and pickups that aren't too thick and high-output.
Part 2 is coming soon!