1 – What is Audio Mastering?

It is the last creative step in the process of audio production. It can be seen as the bridge between mixing and replication of your CD, DVD, Bluray, Vinyl, K7 or generation of files to be used on the web.

So we have the last opportunity to improve sound quality, correct problems or minimize deficiencies not detected in the previous steps of recording and mixing.

The main goal is to make your audio project sound solid and translate as best as possible when played on several different sound systems such as i-pods, boom boxes, home theathers, P.As, hi-fi systems, car systems, multimedia Pcs, etc.

Mastering requires critical listening; however, software and hardware tools exist to facilitate the process. Results still depend upon the accuracy of speaker monitors and the listening environment.

Common tasks usually perfomed here at Alécio Costa Mastering: 

1 – Sequencing and spacing;

2 – Edits, removal or reduction of noise when necessary;

3 – Compression/Expansion;

4 – Subtractive and Additive equalization, performed in Stereo and/or M-S (mid-side);

5 – Macrodynamic correction – consistency between verses, bridge and choruses;

6 – Harmonic and/or ambience enrichment;

7 – L-R balance;

8 – Fading and cross-fading;

9 – Limiting;

10 – Generation of a solid, unique final product, with loudness and dynamics compatible between tracks, aiming the standards of the target musical style as well as the market needs;

11 – Generation of a master/sound files optimized for formats such as: CD Audio 44.1kHz 16 Bits Dithered, DVD 48k16 or 48k24, Mastered for itunes (MfiT) 44k24-96K24, MP3s, etc.

2 -Our Methodology:

As we receive your mix files, we perform verification of data content, bit depth, headroom, L-R balance, presence of critical noises or glitches.

For every song, we send the client a full written PDF called “Technical Report”. We may include some suggestions or ask for some minor mixing adjustments, when necessary.

With this approach, original mixes will become potentially improved for the mastering stage.

We accept up to three mixes of the same song, once the original arrangement and mix balance is kept. With mix improved, client may resend it labelled as “reported mix” and we generate up to three mastered versions so that he can choose his favorite one.

From this point, we perform the mastering process of the whole project.

If mixes are altered after the technical report sent/mastering process concluded, they will be charged as additional songs or as a percentage of the unitary price.

Instrumental versions or alternative versions ( no lead vocal, no lead instrument, etc) are charged as 30% of the pricing per song.

A deposit of 50% of the overall project cost is required for booking and for starting of the job. The final payment must be done prior to sending the final mastered versions.

Clients may downlod the final versions from our ftp server and burn their CD or DVD reference discs. Also, we may ship physical reference media discs ( CD-R, DVD-Rs) to your address. In this case, client is responsible for payment of the shipping and testing integrity of this material as it reaches his address/pressing plant.

We accept international paypal transfers or direct deposits to Brazilian Banks ( Itaú and Caixa Econômica Federal). Japan, Portugal and U.S.A have partner agencies (Iwata Japan, Millenium Portugal, Citibank U.S.A).

3 - e-Mastering:

You may send and receive your files using our FTP server. It is safe, never expires and there is no need for keeping dozens of e-mail links!

As we book your mastering, you will receive an e-mail including some technical tips/recommendations as well as a link/password to our secure server.

Alternatively, you may also use your or

4 – Accepted Formats and Technical Recommendations:

Formats: Preferrably 24 Bit Wave, AIFF files with sample rates of 44.1kHz – 96kHz

We may also work with 16 bit Wave, AIFF files

We do not recommend “lossy” formats such as MP3 and AAC.

Physical Media: We accept CD/DVD/Bluray Data, Audio CD, HDs and K7s

Technical Recommendations: Files with Peaks under -3.0dB, preferrably under -6.0dB, RMS < -19dB.

Mastering process will provide better results if you send us mixes with reasonable headroom ( at least -3dB FS), free from heavy master buss processing ( limiting, exaggerated compression, stereo imagers, exciters).

5 – ISRCs and International Databases ( iTunes and all music):

We may add your ISRC codes into your CD master. Please, be aware that ISRC Codes are not embedded in the audio files on a CD or CDR – they are written on a DATA portion of the CD (just like the track ID’s). Also, ISRC codes are not embedded in MP3s upon conversion from an audio file.

We may also add ISRC codes to individual MP3 files if you wish. Jaykozz is a simple software that permits handling of the id3 tag portion of an MP3 file: you may add a picture/album cover, ISRC, website, lyrics, production team, etc.

CDDB (CD database) is when you type in your content (artist/song information) into iTunes library by hand. Windows media Player requieres you to send your CD to .

AMG will add any product submissions to the database as long as they are commercially available in their country of release. The best way to ensure that your title receives full coverage is for you to send them one copy of the product along with any relevant promotional materials, such as press releases and artist photos.

Concerning the free iTunes database, you must have a computer connected to the internet so that iTunes might send a digital signal to recognize the audio signature of the music and then inform your computer to display the song/artist name.

If your computer does not recognize your CD, then you must lod your CD audio files into iTunes, then select “get info” (right click) for each song and manually type in the names, artist name, year for every song. Next, you select from the top menu of iTunes > ADVANCED > submit CD Track Names.

It may take a few days before the information that was typed to show up on every computer that is connected to the internet.

6 – Investment:

Pricing per song, up to 7 minutes long, Stereo Mix File: US$50 (includes technical report, 3 mastered versions) . Songs overs 7 minutes are charged U$10 per additional minute.

Alternative versions of the same song/ mix ( no vocals, etc) : US$32.50

Stem Mastering, up to 7 minutes long: please, contact us for quote (Stereo Lead Vocal, Stereo Bass Guitar, Stereo remaining content mix, stereo drums)

Master For Itunes (MfiT), up to 7 minutes long, Stereo Mix File: : US$75 (includes regular CD Master)

Generation of Red Book 4X CD Masters : US$10/disc

Conversion to MP3 320 + embedding of ISRC + Artist Data : US$50 ( 10-song album)


7 - Equipment:


Dynaudio BM Series (Dinamarca)

*Analog Gear:

Pendulum OCL2 Tube/Optical Compressor/limiter

Crane Song STC8 Class A Compressor/limiter

Crane Song Ibis Mastering EQ

Avalon Pure Class A AD2055 equalizer

Crane Song Hedd 192 AD DA + Harmonically Enhanced Digital Device

4 Sebatron VMP4000 quad valve Line driver/mic pres


*Digital Processing:

TC MD3 TDM Suite

Hedd 192 Harmonic Exciter

PSP Neon HR, PSP Xenon, PSP Master Q , PSP VW II

Digidesign/Avid Power Dither, Phase Scope

Waves TDM Bundle (L3 Ultra, PAZ, Center)

Sony Oxford Inflator , Sonnox Fraunhofer Pro Codec

Izotope Ozone 5, Fab Filter Pro L

DMG Equilibrium


Pro Tools HD2 Accel, Digidesign 192 I/O Digital, Adat Bridge24, MAC Pro 2.66 Quad Core.