A master that sounds great on your monitors but thin on a phone, boomy in a car or hollow on a smart speaker has failed. Portability - translation - is one of the main reasons mastering exists. This chapter covers how to test it and fix what you find.
Where people listen
- Phone speakers - tiny, almost no bass, often mono.
- Earbuds and headphones - detailed, exaggerated stereo, variable bass.
- Cars - boomy, noisy, with bass build-up.
- Laptops - thin and small.
- Smart and Bluetooth speakers - often mono, with heavy built-in processing.
- Clubs and PA systems - huge low end, usually mono or summed low frequencies.
Low-end translation
The low end causes most translation problems.
- Small speakers cannot reproduce sub-bass. If the bass line exists only below 60 Hz, it disappears on phones. Make sure the bass and kick have harmonic content in the 100 Hz-1 kHz range - saturation helps.
- Large systems exaggerate excess sub. Too much energy below 40 Hz eats headroom and can muddy club playback.
- Keep the low end mono.
Mono compatibility
Many systems play in mono or sum the low end to mono. Check the master in mono:
- Does anything disappear or go hollow? Stereo widening and phase-y effects are the usual culprits.
- Does the vocal level change?
- Does the low end stay solid?
A correlation meter helps: readings close to zero or negative signal problems.
Midrange and harshness
Small speakers emphasise the midrange. A master that sounds smooth on monitors can be harsh on a phone if there is too much energy around 2-5 kHz. Check vocals and synths on small speakers.
Codecs
Streaming services encode your master to lossy formats. Loud, dense masters with lots of high-frequency energy are most likely to pick up artefacts. Preview your master through a codec - many plug-ins offer this - and listen for swishy highs, smeared transients and added distortion.
The translation checklist
- Monitors at moderate level.
- Headphones.
- Earbuds.
- Phone speaker.
- Laptop.
- Car.
- Bluetooth or smart speaker.
- Mono.
- Club or large system, if relevant.
- After a lossy codec preview.
Make notes on each system. If one problem appears on several systems, fix it. If a problem appears on only one, it may be that system's character - compare with your reference on the same system.
Compare with references everywhere
On every system, play your reference too. If both sound bass-heavy in the car, the car is bass-heavy. If only your master does, your master is.
Do this now
- Run your master through the full checklist and write down what you notice on each system.
- Fix the most common problem and run the checklist again.
- Check in mono and on a phone speaker before every export from now on.