Every few days or so, someone new to recording to computers, or new to recording to a mac, or new to recording in general, wants to know such things as:
1. how do i record to garage band?
2. how can i record using the line in?
3. what kind of soundcard do i need? (my personal "favorite")
i'm hoping this thread can serve as a primer the curious before trudging on to more specific questions.
i'm an amateur musician and amateur recordist. i first starting using macs for music in 1986 with MOTU's Performer (and a Southworth MIDI interface -- anyone remember them?), slaved Perfomer to SMPTE timecode coming off tape in the 90's, and these days record using ProTools LE and programs like Reason, plus some of my old 80's synths.
whether going to tape or computer, the recording process is basically the same as it's been for decades, but those new to the experience may become a little lost by a lack of understanding of the process and the plethora of hardware and software choices available today.
A Brief Overview of Recording
Sound recording consists of capturing some kind of time-based signal, either from the analog or digital domain, and committing it to some kind of medium, either analog or digital, from which the signal can be played back.
One example is a person dictating into a handheld tape recorder. Though this example is simple, it does contain the basic parts of recording a live signal: the source (voice), the mechanism which translates sound waves into electrical signals (the mic), and the recording mechanism (magentic tape).
Playback goes in reverse: magnetic waves are converted to electrical, which are converted to sound waves (the speaker). for purposes of this discussion, i'll skip the biomechanical parts of listening and the conversion therein (mostly because i don't understand it very well :-)
recording to a computer isn't much different. though the source may be something other than moving soundwaves, the information must end up as a digital stream of 1's and 0's to be written to a hard drive (the recording mechanism).
Getting Sound Into a Mac
Macs can record through a variety of ways:
1. line in through the audio-in port*
2. mic in through the audio-in port*
5. PCI card
6. optical digital in
* not all macs have audio-in ports
** not certain if anyone's implemented this
let us note that, for 1) and 2) above, those signals are analog. all other incoming signals are digital.
line in through the audio-in port
macs with analog audio-in ports feature a cheap analog/digital converter tied to the audio-in port. this means that a line can be fed from, say, an outboard mixer and the mac will be able to record it, though with not much quality.
let us note that line level is not the same as Hi-Z, which is a high impedance signal from, say, an electric guitar. personally, i don't know if this port can also accept a Hi-Z signal, perhaps someone else can chime in.
mic in through the audio-in port
mic-level signals are significantly lower than line-level signals. the device which increases a mic-level signal to line-level is called a microphone preamplifier, aka mic pre aka pre.
though the mac audio-in port does have a mic pre built-in, it is accessible through an apple proprietary connector called PlainTalk. it seems this connector is longer than a standard 1/8" plug and can access the mic pre's phantom power. therefore, plugging in an OTS condenser microphone, with an XLR to 1/8" adapter, won't work.
USB and firewire
once we get to these ports, we're talking about connecting some kind of computer/audio interface. sweetwater carries a number of such interfaces, which can be accessed here
these computer interfaces typically offer analog ins, such as line level in, Hi-Z in, and microphone in. any mic interface will have a mic pre behind it, and probably phantom power, to power mics which need external power, such as condenser mics.
these interfaces will also have converters in them, at least analog/digital and usually digital/analog, for monitoring purposes. a major differentiator among models is the number of channels. there are many models with 2, 4, and 8 channels.
other differentiating factors are quality, bundled software, brand and other features, such as headphone outputs, the ability to rackmount, and low-latency monitoring.
advantages of such boxes include a higher quality pre and converter than what's built into the mac, increased channels, one-stop shopping and availability of features not offered on the mac.
disadvantages include, in general, a quality reflecting its price and a limited ability to upgrade components singly.
these are similar in concept to the USB and firewire boxes, though they obviously connect differently and they tend to cost more and have higher quality. some are not all-in-boxes, but rather simply converters, requiring a separate purchase of pre's and other hardware.
getting sound in, conclusion
as should now be obvious, there are a variety of methods to getting audio into the mac. each user must determine for himself which method is most appropriate for their situation. obviously, if one wants to multi-track an entire drumset, the audio-in port will not suffice.
budget constraint is an obvious determiner. as i like to say, you basically get what you pay for.
but regardless of which method is used, the audio is now in the mac, digitized, and ready to be recorded to hard disk.
Before the Sound Gets In
How the sound gets in depends on what's being recorded, though the basic process is the same. let's look at what's needed to record a vocal:
singer -> mic -> mic pre -> a/d converter -> mac
whether you're using a PlainTalk mic, or an sm57 and a presonus mic pre and an m-audio converter, all those components exist. that's important to understand, as it gets confusing when one plugs in a USB mic (samson makes one, for example), which seems to bypass the pre and converter (it doesn't, they're built into the mic).
so which is better? that samson mic costs $80. the sm57/presonus/m-audio chain costs under $500. people routinely use chains costing thousands of dollars. again, you get what you pay for, but it's entirely possible to get a good sound out of cheap gear. so i suppose the "best" is what fits in your budget and you can use to get the sound you want.
many signals are not mic'ed. for example, a bassist could go direct (by using a Hi-Z in, for example), or a hardware synthesizer could have a digital output, or the synthsizer could be in software. each example implies, or even dictates, its own signal chain. however, every analog signal must be converted to digital at some point in order to be recorded in the mac.
a note about mixers: given the state of interfaces today, it is not absolutely necessary to use a mixer, though some like to and it's easy to integrate into a setup. i've seen a lot of confusion regarding the relationship between mixers and computer/audio interfaces, which is understandable given some feature overlap.
when it comes down to it, mixers are handy if you want to mix together signals outside of the computer. they can also offer a number of mic pre's and EQ's on a budget, plus offer some handy monitoring features. and i've found that cheap ones sound like crap (imho). then again, i think the same of cheap interfaces (imho). bottom line is they can be useful but aren't always necessary, depending on the setup.
After the Sound Gets In
there are a number of programs which allow multi-track recording, such as Garage Band and Digital Performer. i'm not going to get into their operation or which one's better than the other, but i will say that the choice of program (or DAW -- Digital Audio Workstation) should be made before the choice of hardware. that's just a personal preference of mine, and necessary if you end up going with ProTools, because its maker, Digidesign, limits the hardware choices available.
in all situations, though, it will be necessary to hear what's been recorded, such as when doing a mix of the song. many people mix what's called "in the box", meaning the computer will be doing all the math necessary to take the recorded (or generated live) tracks and make a stereo mix of it.
this mix will be routed through a d/a (digital to analog) converter in order to be heard. perhaps it's the one tied to the headphone output, perhaps it's in your computer/audio interface, perhaps you're sending it out the digital s/pdif line to a dedicated d/a converter. there are a number of options and i bring it up to again hammer home the point: you get what you pay for.
there are a number of ways to get done what you want, for all budgets, all skill levels, and all sonic qualities. what's right for your particular situation can be determined only by you, and please recognize that when you said "i want to record to my mac", you were (perhaps inadvertently) also announcing yourself as an engineer. and being an engineer means being faced with and making a seemingly endless stream of choices, including budgetary.