Reason is a complete, self-contained application by Propellerhead Software used to compose and produce popular electronic music. It emulates the look and feel, as well as the sound, of a whole music studio filled with synthesisers. Its two main parts are a sequencer and a large virtual rack filled with various synthesisers, samplers, effects and mixing desks.
I've been using it for the last few years to produce all my music and songs. In that time, I've learnt a few things about it.
What Reason is bad for
If you use acoustic or electric instruments - say you write rock music, for example - then you can pretty much forget about using Reason. Although it's pretty easy to get the occasional snippet of sound into it from elsewhere, it's about as far removed from a multitrack recorder as you can get while still being able to bear the label of sequencer.
Reason's sequencer has nothing to do with audio, and its samplers will only play sounds from the beginning. You can't just lay down a lead vocal, then some backing vocals, then some guitar riffs and drums. You can painstakingly import all of these into Reason's samplers, but that would be missing the point. There are several good pieces of modern software that act like multitrack recorders, and Reason is not one of them.
Propellerheads have since released another application, Record, that can work well with long recordings of tangible instruments, so for guitars and vocals, it may yet be possible to integrate studio style recording with Reason. Personally, I'm not entirely convinced about the usefulness of Record, as there are plenty of well established sequencers out there that accomplish the same task. Reason, on the other hand, is unique.
Reason is self-contained. This means that it can't use any plug-ins. In other words, you can't control software synthesisers or effects units made by other companies from within Reason. It doesn't work with hardware synthesisers either, so you have to fully embrace all of Reason, or leave it entirely.
If you want to use it alongside plug-ins, then you can run both from within another sequencer. I've never tried this myself because I value Reason for its ease of use, and I imagine that using it with another sequencer gets rather complicated rather quickly and again arguably misses the point of using such an easy piece of software in the first place.
What Reason is good for
Where Reason really shines is in making electronic music with few, if any, imported sounds. As long as you're content to use its built-in synthesisers -- and believe me, you should be now that it sports rackmounts like Thor -- then you'll find the developers' stance on making it a stand-alone application has some distinct advantages. Arguably the most important one is that, because their software isn't talking to anyone else's, it's very stable. I've been using Reason for many years, and it hasn't crashed on me once.
Like all purely software based studios, Reason also has the advantage over hardware that it supports total recall. This means that when you save your song, then open it again several days later, it remembers the exact position of every knob and slider on every synthesiser. Hopefully anyone new to making electronic music will just take this for granted, but compared to a studio full of tangible synthesisers, it's a phenomenal step forward in convenience.
Getting more sounds into Reason: ReFills
Reason has its own proprietary format for importing and exporting patches and samples, called ReFills, which at first glance seems like a disadvantage if you already have a bunch of seemingly incompatible sample CDs lying around. However, a feature of Reason that seems to get little press is an inconspicuous application that comes with it, called Reload.
The Akai S1000 sample CD format is probably the most popular one there is, and Reload lets you import any Akai S1000 sample CDs into the ReFill format that Reason can use. You can get tons of sample CDs very cheaply now because musicians are all moving to software and abandoning their Akai samplers, so this gives you access to some of the best sample libraries at very reasonable prices.
Unlike the original Akai compatible discs you import them from, the ReFills that pop out of this program also have the advantage of being plain old computer files that can be easily backed up for safekeeping.
Reason can also import SoundFonts. While this isn't a particularly popular format, Digital Sound Factory offer a lot of the E-mu range of romplers in SoundFont form, meaning you can buy the preset sounds from these popular rackmount instruments and compose with them using an interface that's simpler and easier than their original hardware was, at a fraction of the tangible machines' cost.
Unlike sample CDs, ReFills can also contain patches for Reason's synthesisers. These take up less space than samples, and are much more useful. You can sync them to the music's tempo, and you can dissect them to work out how their sounds are made and to make subtle changes to taste.
You really shouldn't need tons of ReFills, however, if you want to make electronic music. As with everything else, knowledge and practice are the most important tools you'll need. Uniphonic's Phat Math ReFill alone is ample proof that even the lowly SubTractor synthesiser that was included in the very first version of Reason can sound just as good and versatile as its more popular hardware rivals, providing it's in the right hands.
Naturally, you also have the option of just buying this ReFill and others like it instead of learning to make your own patches, giving you instant access to hundreds more sounds to play with.
The rack
Each device in the rack is such a realistic and versatile piece of equipment that each one really deserves its own review. Suffice it to say that Thor alone is quite possibly the best synthesiser I've used, beating even tangible devices I've owned hands down. (Admittedly, this is partly because I have neither the money nor space for a modular synthesiser, but even if I did, it wouldn't have total recall, so I'd probably only end up sampling it and using the samples in Reason anyway.)
Note that none of Reason's devices is multitimbral, for a very good reason: if you want to play more than one sound at a time, the simplest way to do it is to just create another instrument. With such an intuitive solution available, it would have been silly for Propellerheads' programmers to have wasted their time putting in a slavish emulation of multitimbral functionality. Instead, you're encouraged to take advantage of the virtual nature of Reason.
The NN-XT sampler has more features than the older but still iconic Akai S1000, and its interface takes at least some advantage of the screen and mouse, making it much easier to use. This is more a sign of how much technology is progressing in general, rather than this product in particular, but a whole virtual rack filled with dozens of NN-XTs loaded with, say, Peter Siedlaczek's Advanced Orchestra would have made any Hollywood composer in the early nineteen nineties seriously jealous.
Professional reverb, compression and parametric equalising are all covered by the various effects units, so you can make your mixes sound professional if you can invest the time and effort to learn how to use them properly. The vocoder is a nice touch, and there's a wealth of synthesisers and effects units that I won't bore you with the details of now. You could spend a very content lifetime mastering Reason's devices. Some people, such as Peff, seem to have done just this, and have written useful books on the subject.
The sequencer
Although it's not as glamorous as the synthesisers themselves, the sequencer is where you'll actually do most of your work composing. Aside from its complete lack of audio, Reason's sequencer has come a long way since its first version. Each instrument can have several note lanes for you to try out various takes, and you can change the tempo and time signature mid-song. Admittedly, these are things that other sequencers have been able to do for a long time, but it's nice to know that Reason's sequencer has now pretty much caught up with the rest.
It's a breeze to record a few bars of music played on a controller keyboard, touch up the notes on screen, then tweak pretty much any setting of any device while the song's playing. I have little frame of reference when it comes to sequencers, but I found Reason's fairly intuitive and convenient.
Conclusion
Reason is a fantastic tool for making electronic music, and quite frankly, given its price, it's a bargain. Some people may quite rightly avoid it because it doesn't play well with others, but if you're content to use it and nothing else, it's probably the most practical, inspiring way there is to write music. I wholeheartedly recommend it (plus a controller keyboard) to anyone who's serious about making purely electronic music.
It's also a good scratchpad to jot down ideas on, even if you rework the song in something else later on. With such first class mastering effects, however, I'd have to wonder why anyone would want to export their creations into anything else in the first place, unless they already used a specific synthesiser or plug-in that they just couldn't give up.
In short, if you can bear to use Reason and nothing else to make music with, you probably should.