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Digital Audio Mastering FAQ


What is mastering?

Mastering is the final step in the recording process, where all the songs are checked for errors and the album is prepared for retail sale. This preparation can include a number of things, but usually involves some sort of additional processing (or "sweetening" as many places like to call it) in order to make songs sound clearer and better. There are a great deal of personal tricks used by various mastering engineers which in part contributes to some of the mystique surrounding their practices. Processing is almost always done on the final mixes, not individual tracks. An example of said processing would be running a song through a powerful and transparent equalizer in order to properly balance the track. Oftentimes, additional compression and limiting is applied to the final mixes in order to give them a more "commercial" sound. In addition to this extra last check processing, more mundane tasks such as properly sequencing the song orders, crossfade editing, and PQ coding takes place as here as well.

What do I bring to mastering? What should I expect in return?

If you plan on taking your mixes to an outside source to get them mastered, ask them what formats they accept. Most big facilities should be able to accommodate pretty much anything. The idea is that you will bring/send them your final mixes in whichever format/sample rate that you have that sounds the best. Oftentimes, the engineer will let you sit in on the session and allow you to give them your input while they work. Once the engineer is done, the ultimate goal is usually the burning of a premaster copy of your CD (along with a PQ printout for the plant) which can be sent to a CD duplication plant along with your artwork, etc. There the glass mastering takes place and your thousands or however amount of CDs should be made. Now of course, many mastering facilities are quite flexible, so if you only need mp3s of your songs or some audio restoration you wont necessarily need a pre-master CD.

NOTE: If you do plan on sending your songs to outside mastering, do NOT:

1) Add extra compression/EQ on the final mix...let the mastering engineer do this...it's what you're paying them for.
2) Try to do any sort of normalizing...once again let the engineer handle this, give them some headroom to work with.

If you're just trying to give your engineer an idea of how you want to sound make them a separate set of your mixes and send them along with your untouched mixes.

Why is it that after its mastered its called the premaster CD ?

The mastering engineer takes the final mixes and matches the sound of all the tracks and levels between tracks and any thing else that needs to be done to "sweeten" the tracks before being burnt to the "premaster CD". Its called this because the true master is made from this premaster CD and is called the "glass master" which is the CD which all the copies are pressed from in a large mass production plant.

What kind of gear is used in mastering?

Without saying, the most important piece of gear used in mastering is the Engineer's ears. Nevertheless, mastering gear has to be of the highest quality in order to maintain audio integrity at all times. Some commonly used processors in the mastering studio would be from such companies as Manley, Sontec, and Crane Song for analog and Weiss, Z-systems, and Waves (L2) for digital. Monitoring is usually done on accurate (re: expensive) full range monitoring systems in acoustically treated rooms. Room acoustics are especially important in mastering studios as mixing rooms are frequently flawed. As far as editing goes, the most commonly used DAWs used are Sonic Solutions and Sadie. Other systems such as Audio Cube, Pryamix, and Sequoia are also becoming more popular. Some cheaper programs such as Wavelab, Sonic Foundry, and Cool Edit Pro can also be used to burn cdr premasters in redbook format. It should also be noted that in upscale mastering facilities pretty much no processing is done on the computer, rather routed through outboard gear before hitting the DAW for final editing and burning.

What are the differences between recording studios and mastering studios?

There is a reason why the best mastering studios are separate from recording studios. Your typical mixing room is not optimally acoustically designed as you have big consoles and racks that get in the way and cause problems. Since mastering engineers as generally considered specialists their gear choices also tend to me much more personal then recording studios which need name brand equipment like ProTools and Genelecs to impress clients. In general you should be wary when a recording studio offers "in house mastering", because oftentimes they just throw some plugins on your songs while listening to them on the same speakers they were mixed on. Unless the studio has a separate mastering room, such "in house mastering" is probably only a marketing tool to get more business.

How much does mastering cost?

Mastering costs can vary greatly depending on where you go. How much they charge generally reflects their previous clientele, quality of gear, and experience. Most high end facilities will end up charging between $400-600 dollars for a mastering job taking around 4-8 hours. Most places charge by the hour, so adjust accordingly if you have a lot of material or it needs alot of work. There are cheaper places and more expensive places which don't necessarily reflect the quality you will get out of them. If you're looking around just talk to the engineer and make sure he/she knows what they're doing and what you're specific goals are.

How do I use X Plugin/Software or gear for mastering?

Use your ears! There are no set rules such as what ratio and threshold to set your compressor or what levels to set your songs at. Don't overdo anything, chances are if you hear an audible difference then you've used too much. Compare your "masters" with non-touched mixes at EQUAL volume. If you're having trouble getting started with the EQ look up one of the EQ primers floating around the web. Just use your ears and if you're monitoring system isn't very good, double check on a range of different speakers.

Pq Coding

PQ Coding is basically just the proper encoding of the track IDs and information in red book form. This includes setting up start and stop IDs for each track, copy protection, preemphasis, ISRC codes (includes stuff like year and record label information), and UPC codes (which the bar-codes you find on the packaging is made from). These are helped to track and identify songs when they are used in copyright and radio type situations.

This type of editing is what mainly separates DAWs like Protools which isn't really used by any mastering houses from more dedicated systems like Sadie and Sonic Solutions.


Why do you get someone else to master your work ?

1. you've been listening to the same songs mixing it for hours on end and have a biased view. I'm sure you've played some of your work you thought was perfect 5 months later and heard all the problems that you should have heard but didn't. That's the major reason. If you must master your own work then wait a few weeks and don't listen to the track during this time.

2. Every room and speaker has its own color. A mastering engineer has dead flat gear and a room designed to have no reflections, not even a mixer. Absolutely nothing in the room between the speakers and the engineers ears. Your room most likely is not perfect and the room effects what you hear even with nearfields.

3. Tracking artists may be great at using an EQ but mastering eq's are completely different animals. Just like you have JACK HAMMERS and your normal hammer and a rubber mallet there's different eqs for different jobs. If your not using the tools every day then you wont do as good a job as a full time mastering engineer. Multiband compressors and the correct dither to use in each situation is something you may not know.

That's 3 good reasons why to get it mastered by a dedicated mastering house which doesn't own a mixer.


I really want to master my own material, what should I do?

If you're just working on your own songs for fun, there is absolutely no reason why you cant go ahead and try to "master" them yourself. The majority of the budget mastering tools come in the form of plugins, directx or TDM. There are a good amount of such plugins nowadays designed especially for use on final mixes and these would probably provide better results then using cheap outboard gear. Some examples of such plugins would be T-racks, Izotope's Ozone, and Waves Gold and Mastering plugins. As long as you don't get carried away and end up trying to use every function or processor you can get your hands on you can do a decent quality job (although it probably wont sound "professional").

Also wait a few weeks minimum after you have finished the mixdown to let your ears get refreshed, and listen to the track and find out what's wrong with it before reaching for any plugins or outboard gear. Only put on what the track needs, if you cant hear anything that's wrong or you don't know how to fix it then don't do a thing and send it to someone else with more experience to master.


A good mastering house in Australia that I know quite well..


More good info at....