Grischa's Atmos room has the best bass decay of any room I've worked on. Yet he barely mentions it.

Ask somebody why they're treating their room and you'll hear "flat response" or "tighter bass." Ask somebody two years after a full build what actually changed, and you get a very different answer.

Let me show you Grischa's.

He's a mix and mastering engineer running Lobos Audio in the south of Germany, and he's been doing it for about 20 years. Reggae, Ska, Balkan beats, a lot of hip hop. About three years ago we started working together on the treatment for his new Dolby Atmos room. Seven speakers around him, four above, one sub. He built every bit of it himself, supported by his family.

On paper the result is ridiculous. The bass decay went from 2.7 seconds in the empty room to about 230 milliseconds. That's the best result I've ever seen in a room I've been involved with, and we got there without a single resonance absorber.

But when we spoke, he didn't bring that up once.

Before: every decision needed a correction

His old room was a room in the family flat. He'd treated it "like one treats a room without knowing much," and by his own account, made it work. He made records in it for years and liked how a lot of them translated.

Still, here's how he described it to me on one of our calls back then. Things consistently came across "so fundamentally wrong that mistakes happened."

That's what a room you can't fully trust does to your ability to mix. Every primary decision comes with a second decision attached. Is that real, or is it the room?

So you build habits around it. You keep the low end conservative because you know it'll come out boomy somewhere else (Grischa loves bass, and he had to hold back on it to make it translate). You take the mix to the car and come back with a list of notes. The kick is too loud. Again.

And sometimes the room just gets on your nerves. He told me he used to walk out of his old room whenever people wanted to talk in it.

None of that shows up in a frequency response. But all of it eats time.

After: one mix

On our last call I asked him how long it took to get used to the new room. I expected weeks. When I myself changed from Adam Audio two-ways to HEDD three-way speakers, I had to adapt quite a bit, and that's the normal experience.

"I think it took me one mix."

Part of that is good planning. He stayed with Genelec, so the character of his speakers barely changed. When he first heard the new pair in the seller's demo room, his reaction was "Ah, I know this sound. This is my sound." Staying in the same speaker family makes the switch a LOT shorter.

But the rest is the room. And this is the line I keep coming back to.

"I think I'm way faster because I don't question stuff. I listen to something, and I do it, and yes, let's go, next."

That's the second decision, gone.

He describes the phantom center as "like a physical speaker," and says you can "feel every little move you do with the pan knob." When you can hear a decision that clearly, there's nothing left to question.

He still does the outside checks, by the way, and he should. A lot of people assume that after this much treatment you can skip them. You can't. What changed is what the check is for. He used to make notes. Now he listens, it translates, done. "In the end, I really trust the room now."

And the kick that was too loud? "It doesn't happen anymore. That's gone."

One major reason being that the bass got another additional fix. When the Atmos system was calibrated, Markus Bertram from MBAcoustics and David Ziegler from Dolby Germany first made sure everything was technically up to spec. But then they gave the low end a push of a dB or two and took a little out around 2.3 kHz, a frequency Grischa can't stand. Merlijn van Veen, who I studied sound system design with, calls that the difference between tuning and toning. Tuning makes the system technically correct. Toning takes it to the next level and makes it something you actually enjoy working on. Grischa can now enjoy his bass in the room and know it'll hold up outside. That's the conservative-bass habit gone too.

What didn't come out perfect

The room is a bit too dry. Grischa says so himself, and he thinks it adds to ear fatigue. We'd planned slats on the back wall to bring some life back, but he just hasn't gotten round to putting them up yet.

After a three-year build he wanted to work in his studio, not build more of it. I get that completely. It's a nice-to-have. It might make long sessions a little easier. But it won't help him judge a mix any better.

Last month I wrote that no graph will tell you your room is done. This is what that looks like in real life. The best numbers I've measured, an unfinished back wall, and an owner who is busy mixing.

It cost him around 30,000 euros by his own rough count, and that's with doing all the work himself. About a year for the treatment alone, three for the whole project, with two kids and a touring schedule running alongside.

So would he do it again? Yes, but he's honest about it. "It takes really a while, and even without family and stuff, it's hardcore." If you're unsure, he'd tell you to take that doubt seriously, because if what you are after is Atmos specifically, headphones with binaural room simulation can get you a very usable reference without building anything.

The part that doesn't fit on a graph on your screen

 When you plan treatment, the measurement is what you can see, so it's what you aim at. And it definitely has its place! Decay times and frequency response are how we know the treatment is doing its job.

But they're the means. What Grischa actually got was that pesky second decision taken away. Fewer notes, faster mixes, a low end he can enjoy, a room people want to stay in.

Even the silence, which he never saw coming. Sitting there at night with everyone asleep, he noticed a silence he'd "never heard before." The noise floor is that low. That's where he starts every mix from now.

So next time you look at a waterfall and wonder if it's good enough, ask yourself something else. How often am I second-guessing what I hear?

I'll leave the last word to Grischa. For him the acoustics were never the point.

"It's like something that has to be good, and if it's good, I'm just leaving it behind and I'm happy."