Mixing and mastering

The stages are related but cannot replace each other.

At Biotroncetra, we start by checking the tracks, hearing your intentions and agreeing on references. You can work with us in Madrid or deliver material remotely. The initial listen identifies problems and establishes the scope before any controls are moved.

A process in four steps

1. 01Brief

   Tell us the goal, available material and preferred date. We review the job before suggesting a session.

2. 02Quotation

   You receive scope, rates, first delivery date and written terms. Booking follows acceptance and the 30% deposit.

3. 03Work

   We follow the agreed scope and discuss changes before carrying them out. The booked time includes planned breaks.

4. 04Delivery

   Review a version, consolidate comments and use the 2 included rounds. Final files and agreed rights follow full payment.

When the project is ready

Mixing works best when composition, arrangement and take selection are settled. If instruments are missing or the structure is changing, resolve those points first. Send a rough mix from your session even if it is imperfect: it reveals decisions that may matter to you. Identify sounds whose treatment should remain and those that can change. An effect that belongs to the arrangement can be supplied alongside a clean version. There is no universal track count that determines quality; function and required work are what matter. Material is reviewed before the mixing price is confirmed. Damaged-audio restoration and additional production are separate tasks.

Export without losing alignment

Export every track from a common start point, keeping its full duration and initial silence. Use 24-bit WAV at the session sample rate; do not change the rate simply to send the project. Check that reverb tails are intact and all tracks align when imported into a fresh session. Names should be clear: kick, snare, bass, lead vocal or harmony, without relying on file-browser order. Print virtual instruments to audio. A proprietary session file may rely on plugins that are unavailable elsewhere. Avoid normalising each track or compressing the master merely to make the export seem louder.

Balance, space and decisions

The first mixing stage establishes level, panning and relationships between instruments. We then address competing frequencies, dynamics and depth. A reference helps describe intention but does not turn your song into a copy of another production. Processing follows the material rather than a fixed list of tools. If a vocal needs clarity, we also consider what surrounds it. Important changes are documented so later rounds remain aligned with the direction. Listening is not based on loudness alone: versions are compared at reasonably similar levels and the arrangement is checked in different contexts, without promising identical reproduction on every device.

What is included

• Technical review of supplied material
• Written agreement on references and scope
• Balance and processing suited to the project
• First version on the quoted schedule
• 2 consolidated feedback rounds
• Final exports within the booked scope

Mastering as its own stage

A master requires an approved mix and a clear destination. We review tonal continuity, dynamics and possible technical issues before preparing the final file. If a defect would be better fixed inside the mix, we explain it rather than hiding it with extra processing. No loudness value guarantees success across every platform. Encoding and normalisation can affect playback, so delivery considers the agreed use. The starting mixing rate does not automatically include mastering; mastering is also available separately. For an EP or album, continuity between songs needs to be considered and quoted specifically.

Feedback that moves the project forward

The 2 included rounds work best with a consolidated list stating timecode, element and desired change. Instead of asking for everything to sound more professional, describe a specific relationship, such as the chorus vocal or a bass entrance. Listen to a complete version before collecting comments and avoid decisions based on faulty speakers. A round revises the approved scope; adding tracks or rebuilding the arrangement changes the job. The quotation specifies the first delivery date and feedback schedule. If several people oversee the project, agree on comments internally so each revision does not alternate between incompatible directions.

Delivery and project archive

We supply the versions described in the quotation: stereo mix, master when booked and listening copies. Stems, instrumentals, a cappella versions and working sessions are not automatically included. Every format needs an agreed purpose. Final delivery follows full payment; rights in original studio contributions are governed by the terms while pre-existing rights remain protected. Working files are kept for 6 months, and you should retain your own copies of both finals and source materials. Distribution, release identifiers and rights administration are outside this technical service.

Rates and conditions

Rates show the 21% VAT-inclusive amount alongside the net amount so you can compare the full cost. The quotation identifies time, tasks and deliverables; a starting figure is not a replacement for that agreement. The 30% deposit is deducted from the total rather than added as another charge. Cancellation is free up to 7 days before the session, with the deposit refunded. With less notice, any charge is assessed under the terms and actual committed work, while preserving applicable statutory rights. B2B invoices have a 15-day payment term when agreed in writing. Enquiries are answered within 2 business days, Monday to Friday, 10:00–19:00 Madrid time. The person booking must be at least 18. If a performer is younger, participation and permission must be discussed with their legal representative before booking.

Questions about this service

Prepare your material with Preparing files for mixing. Service terms. Contact and booking.