In this second installment of our three part series, Tom Volpicelli of The Mastering House answers three need-to-know questions about mastering.

4. What are some tips to help ensure the best possible master?

Audio quality can be very subjective. Before hiring a mastering engineer for a project you should have a clear objective on how you would like the finished project to sound.

Communication of these objectives between client and engineer is a key component to the success of a project. The language used to describe the character of audio can be ambiguous.

Terms like “brassy,” “fat” and “present” mean different things to different people.

One of the skills of a great mastering engineer is to able to translate this loose terminology into the specific technical processes required to achieve the client’s goals in a non-obtrusive way.

Some mastering engineers find reference tracks from clients to be helpful. Reference tracks can be worth a thousand words, because they serve to demonstrate the sonic objectives of the client.

My personal preference is to receive mixes that are as close as possible to what the finished product should sound like, but with enough leeway to be able to manipulate the sound in order to mold a cohesive album. Some general tips toward achieving this are:

Knowing your room and monitors. If you are using smaller nearfield monitors for mixing, be sure to listen to the mixes on a system that has extended bass to ensure that there are not low end bass problems.

If your monitors or room “color” the sound in any way be sure to compensate to ensure that the mix will translate well on other systems.

Fix track related issues before mastering. Listen for issues like excessive sibilance, uneven or exaggerated frequencies, phase or polarity problems, bad edits, depth and width of the sound field, and the relative levels of instruments and vocals.

I recommend listening to a mix in mono in order to hear if anything disappears or becomes exaggerated as well as listening to the mix at different levels and positions within your room. This can sometimes make an issue more obvious due to a different perspective.

Leave enough of the mix dynamics intact so that the engineer can make adjustments not only in the overall level but in the punch and clarity of the transients.

Don’t use any processing on the master bus that will interfere with processing that is best performed while mastering. This may include exciters and harmonic enhancers, EQ, normalization and limiting used to achieve a higher overall volume.

Leave the heads and tails of a mix intact so that there is room ambience before the music starts and enough of the music at the end to be able to tailor the fade out.

Having a bit extra at the start and end can also be useful so that a “noise profile” can be created for noise reduction systems that use this as a technique for removal of broadband noise.

Use mute and volume automation to remove extraneous noises from the individual tracks.

Noises include: headphone bleed when the vocalist is not singing, hum from electric guitars during breaks, and a drummer who may lay down his sticks after the cymbals fade at the end of a song, but before the final fade out of other instruments.

5. What should I send to the mastering engineer?

Mixes should be delivered in a format that alters the sound by the least amount.

For digital mixes, an uncompressed format (AIFF or WAV) should be used rather than compressed formats like MP3 or AAC.

You should speak to the mastering engineer that you will be working with to verify the formats that they accept.

I recommend staying with the same sample rate used in the original tracks, unless mixing through an external converter.

In that case, increasing the sample rate has its benefits. The bit depth should match the one used during the mix session rather than supplying tracks on audio CD where truncation and optionally dithering of the original tracks is applied.

I also prefer that digital mixes be sent as a single stereo interleaved file rather than split stereo files in order to help ensure phase coherence.

While a standard when sending analog tape for mastering, reference tones are becoming a lost art with digital.

If mixing through an analog board or to an external device, having an unaltered 1k reference tone (corresponding to 0 VU on the console) can help to identify issues where left and right channels are not calibrated or set properly.

If you are not attending the session, be sure to send all documentation regarding the sample rate, bit depth, format, and a listing of the filename with the full name of the song for each file.

Also note if there are alternate mixes of the same track (e.g. vocal up/down). A listing of the song order is also necessary along with requirements for song spacing and fades if not printed on the original mix. If CD text, UPC/EAN or ISRC codes are to be added to the final CD they must also be included in the listing.

Documentation may include information about your audio chain such as equipment and processing used (particularly if applied on the overall mix), what you feel are some of the enhancements that you would like to hear in each mix, along with any other information that you feel will be useful to the mastering engineer.

6. How much will mastering cost?

Prices vary depending on the profile and experience of the engineer, previous credits, along with studio costs and overhead. Typical rates are based on:

     - Flat rate per album usually tiered based on the total number of tracks,
       sometimes with a total hourly cap.
     - Flat rate per track or number of minutes per track.
     - An hourly rate that can include additional costs for media due to time spent
       verifying and listening to the disc.

Some studios may also charge more for attended sessions versus non-attended sessions where the final product is delivered and approved by mail or Internet.

Costs for mastering vary anywhere from $10 per song to $500 per hour for well regarded professionals. Given that mastering is a subjective service-based business, as opposed to a commodity which can more easily be compared, caveat emptor applies.

Assuming that both quality and cost are considerations, set a realistic budget for mastering at the start of your project. Sometimes independent artists will not have anticipated the costs for mastering until a project is completed.

This forces them to use lower quality alternatives that are not necessarily best for their project. It’s a good idea to research the studios that will work within your budget. Call them to discuss the details of project and their approach.

In addition to gaining a better understanding of their process you will be getting a feel for the quality of their customer service. Some studios provide a demo of your material to ensure that they meet your expectations; others may charge for this service.

In either case, this is a good way to hear the quality of their work before committing to the cost of an entire album.

Tom Volpicelli is the president and founder of The Mastering House and has an extensive list of mastering and mixing credits to his name.

Editor Note: This article is Part II in a series of the 10 most frequently asked questions about mastering. Stay tuned for Part III where we’ll cover the remaining 4 questions and be sure to check out Part I in the series.