Every mix we deliver gets played on a phone before it leaves the studio. Not as a last check. As the first real one.
That sounds a bit backwards, I know. We've got good monitors, a treated room, all of it. But almost nobody hears your ad the way I hear it in the studio. They hear it on a phone held at arm's length, on a laptop with the fan going, on a TV while someone's emptying the dishwasher. So that's where it has to work.
What disappears on a small speaker
The bass, mostly. Everything under roughly the low mids just isn't there on a phone. No big deal, unless the whole track is resting on a lovely warm low end (and a lot of them are), because on a phone that suddenly turns thin and your voice-over ends up standing there more or less on its own.
Small details go too. That lovely reverb tail, the quiet texture in the background, the subtle swell before the product shot. On monitors they make the mix. On a phone they're simply gone, and you only find out once it's live.
The three places we listen
First the phone, held the way people actually hold it. Then cheap earbuds, the kind everybody has rather than the expensive ones in the studio. And then a room with some noise in it (a café, a kitchen, the office) because if the voice gets lost there, it's too quiet, full stop.
Only after that do we go back to the monitors to make it sound nice for the people who do have a good system.
Why it matters for a brand
Your sound logo, your voice-over, your music: it all has to survive the worst speaker it'll ever play on. A sound logo that only works in a quiet room isn't a sound logo, it's a demo.
And honestly, it's the cheapest quality check there is. It costs nothing. You don't need a studio for it either. So the next time a mix lands in your inbox for approval, skip the desk and the good headphones for once, put it on your phone and wander into the kitchen with it. If you can still follow the voice and you still know whose ad it is when it ends, you're fine, and if you can't, send it back with exactly that remark, because it's a perfectly good note.