Many of our members and ex-students already know how we run our courses and that we often hold Live Workshops on a variety of topics. Sometimes it's just to let off some steam and hang-out with our study mates. Sometimes we post a couple of snippets for potential students to get a feel for our courses, and understand we are dynamic! This article contains a great overall description of audio mastering by Ben Morgan, one of our Production Advisors.
[ben-m]Mastering is usually the last part of the recording chain, working with stereo files. The mastering engineers job is to get as good a level as possible out of the track and to ensure that (if working on a album) the tracks have a sonic 'cohesion'.
[ben-m]The mastering engineer will usually work with a few tools at his disposal usually; compression (multi-band and single band), EQ, Limiter and Phase tools. The modern day trend in mastering is to create tracks as 'hot' as possible, do you know what I mean by 'hot'?
[mommi] Yes, i think
[Albow] Isn't it subjective?
[ben-m] 'Hot' in audio terms is a very high level.
[Albow] High as in high volume?
[ben-m] Well, yes, but more in terms of gain than volume
[Albow] Explain please :)
[ben-m] Well, volume is obviously something that we, the end user, can alter with our stereos etc., gain on the other hand is implicitly linked to the recording process. So a hot level would mean that the signal (which would be a voltage in the analogue world, or binary numbers in digital) is near the maximum possible. As you can see, volume is seperate to this as we can change the actual physical level we hear the song but we can't change the gain structure that has been put in place during recording/mastering.
[ben-m] Is that clear?
[mommi] Yes
[ben-m] Albow, you getting that?
[Albow] Yeah the concept is clear. I imagine there's more to getting a 'hot' finish than turning up gain on everything right?
[ben-m] Yes, indeed, and this is the mastering engineers job. The mastering engineer in the current climate will use a combination of compression and limiting to ensure that hottest level possible. This is in contrast to mastering conventions in say the 60s or 70s where the songs were allowed more dynamic freedom. This is why old records often sound quieter compared to for instance the latest kylie track. Also with mastering any phase problems must be identified as many records that will be broadcast on radio will be heard on single speakers (i.e. transistor radios). Any phase problems incurred in stereo must be resolved to ensure that on mono playback nothing disappears. However, for your practical the levels will be of more importance.
[ben-m] Mastering compression would usually involve a relatively low ratio, often in the region of 1:1.2 or so and a low threshold. This would mean that a lot of the signal will be compressed but not at a drastic ratio. A limiter may be used to introduce a few more dBs of level, and the file will usually be normalised to a level. One important thing - when normalising a file for use in CD players etc dont normalise to 0dB(the max level allowed in digital systems before clipping occurs). If a signal was at the maximum level in the digital domain it would be represented purely by 1s and this can cause problems with many CD players. Normalise to a level such as -0.02dB or similiar.
[ben-m] Is that clear
[mommi] Yes
[Albow] Yep
[audiocourses] Great stuff Ben!
[mommi] Ya right chris
[audiocourses] One small think to think about guys. Ben mentioned normalising, which I often use if I have to, though I am aware many engineers frown on it's use. It is a process which can be left out. (the least amount of digital processes the "cleaner" the signal, or more faithful to the original). Not only that, normalising will also raise the noise floor. So look at expansion, as a way of eliminating noise floors. Like mommi did with BJ.
[mommi] Oh don't you dare remind me
[audiocourses] hehe.
