In 2018 Zagat asked nearly 13,000 guests what irritates them most in restaurants. The top answer was not the food, not the service, and not the prices. Noise - 24% of guests named it as their number one irritant.

Over the years I've noticed a simple thing: almost no one treats restaurant acoustics as a question of money. A restaurant invests in the kitchen, the team, the interior - and a guest who came once never comes back, and the first thing anyone checks is anything except how the room actually sounds on a Friday at full capacity. Yet a guest reacts to sound with their body before they even have time to think about it.

Why noise decides whether a guest comes back

Here's the trick with acoustics: a guest almost never complains about it using the word "noise." They will write "we couldn't have a proper conversation" - and more often they write nothing at all, they simply choose a quieter place next time.

But where a review does get written, it hits the rating directly. Underwood and Wang from the University of Nebraska (2024) analyzed online reviews: where a guest mentions loudness, the overall rating is on average a full star lower - even when the food and service are praised. It is a correlation, but a consistent one. And the British charity Action on Hearing Loss, in a survey of about 1,200 people, got an even harsher result: 91% said they would not return to a place that is too noisy, and about 8 in 10 had at least once left a restaurant earlier than they had intended because of noise.

The guest doesn't come back and thinks the problem was the kitchen. The restaurateur thinks the same - and changes the chef.

Why you physically cannot talk in a noisy room

What's at work here isn't "loud and unpleasant" but a specific mechanism. For a conversation to flow easily, the other person's voice needs to be about 15 decibels louder than the background - that is the rule of thumb acousticians use. As soon as the background creeps up to the level of the voice itself, words become hard to make out, and the Lombard effect kicks in: a person instinctively raises their voice, by roughly 0.3-0.6 dB for every extra dB of background, automatically, with no intention at all (Lane and Tranel, 1971). Everyone raises their voice in response to their neighbour, the loop winds up, and the room starts to make noise on its own.

Now add a dozen other conversations happening at once - and the brain has to pull a single voice out of the general mush. This even has a name, the "cocktail-party effect" (Cherry, 1953): the more people talking and the more strongly the sound bounces off the walls, the more sharply intelligibility drops. That is why "asking guests to speak more quietly" doesn't work, and changing the music isn't a fix either: the problem is not the loudness of any one person, it is a room where sound reflects instead of being absorbed.

And this is already about money, not only comfort. Bottalico, Piper and Legner (Scientific Reports, 2022) measured the effect on real guests: from about 57 dB onward people start to strain their voice, conversation becomes harder - and along with that, the urge to leave grows and the willingness to stay and spend falls.

How noise changes taste itself - this is physiology, not preference

The most surprising part: sound changes not only the mood but also how food is perceived on the tongue. Taste is in fact assembled in the brain from all the senses at once - sight, smell, sound, touch - and not only on the tongue. That is the central conclusion of Charles Spence of Oxford, who spent two decades studying how the signals of different senses combine into a single impression. Spence, by the way, cautions against neat, precise percentages like "80% of taste is smell": it sounds convincing, but there is no rigorous data behind such a figure.

This sounds like laboratory exotica, but it has a practical side too. In another study the very same crisp seemed fresher and higher-quality to people when its crunch was amplified - the authors, incidentally, received an Ig Nobel Prize for this work (Zampini and Spence, 2004). And at Heston Blumenthal's Fat Duck an oyster is served with a recording of the sound of the sea: under the sound of waves and gulls, guests rate the same oyster as more pleasant than under an urban background. Sound is, basically, one more seasoning.

And it works both ways. A loud background mutes taste: under noise of around 75-85 dB people rated sweetness and saltiness lower, and crunch stronger (Woods et al., 2011); under aircraft-cabin noise sweetness was suppressed while umami was enhanced (Yan and Dando, Cornell, 2015). Across different studies the effect reproduces in different ways - it is not "proven a hundred percent" - but the direction is consistent: in a noisy room the guest eats something not quite like the dish the chef intended. The cook pours their effort into the kitchen - and part of that effort simply doesn't reach the guest, because of how the room sounds.

RT60: the one number worth knowing before the project even starts

RT60 is the reverberation time: how long sound lives in the room after the source stops. Concrete, glass, open ceilings, bare floors - today's fashionable aesthetic and an acoustic problem by default.

RT60 can be roughly estimated yourself, with a phone, in 10-15 minutes (apps like Room EQ Wizard). It's a perfectly normal starting point even before you talk to an architect.

There is a subtlety here, revealed by a field study of 12 Berlin restaurants (Steffens, Wilczek and Weinzierl, Frontiers in Built Environment, 2021): reverberation spoils the impression mainly because it makes the room louder. Remove the loudness and the separate contribution of reverberation almost disappears. The practical takeaway is simple: damp the reverberation and you lower the overall noise level, and everything else along with it.

What to tackle first when RT60 is high - the ceiling. It is the largest reflecting plane in the room; acousticians advise covering on the order of 50-60% of its area (an industry rule of thumb). The right suspended panels work both on the sound and on the look - as on our ceiling at J'PAN.

Who gets forgotten in this conversation - the staff

Usually noise is discussed from the guest's side. But the waiter, the bartender and the cook spend not an hour and a half in the room, but the whole shift. And for them it is no longer a question of comfort but of health.

I bring this up not as a scare story, but because good acoustics are also a matter of caring for the team that works for you for years. A well-tuned room takes the load off not only the guest, but also those who spend the whole evening on their feet in it.

What it comes to in money - honestly

This is usually the point where people start inventing percentages: "noise cuts the check by such-and-such." I won't quote such a figure, because in any rigorous form it doesn't exist, and the data honestly contradict each other. In a bar, on the contrary, loud sound speeds guests up: in a field experiment at 88 dB instead of 72 people drank faster and ordered more - on average 3.4 drinks against 2.6 (Gueguen et al., 2008). And with Bottalico's older guests it is exactly the reverse: noisy means they wrap up and leave sooner. So anyone who names a precise "minus so-many percent to the check from noise" simply made that number up.

What no one disputes: noise spoils the experience - the conversation, the taste, the desire to come back. And whether a guest returns or not is the same money, just deferred in time. The size of the effect in your specific room we don't guess at, we measure it on site: we look at how guests behave by zone and how long they sit, and tie it to the revenue. Before and after an acoustic fix, it shows up right away - whether people became more comfortable sitting there or not.

Music deserves a separate note - it is also acoustics, and here the lever is genuinely in our hands. A slow tempo holds a guest longer, and dwell time is the main predictor of the size of the bill (Caldwell and Hibbert, 2002; in a recent experiment, Malcman et al., 2024, guests sat on average about 40% longer under slow music). In fairness: in that same experiment the average bill itself did not change noticeably with tempo - so music governs turnover and the rhythm of the room rather than the check directly. Use it deliberately, don't leave it to chance.

And the pleasant part: acoustics is one of the most cost-effective interventions in a dining room. Panels on the ceiling, soft surfaces, partitions - these are days of work with no need to tear open the finishes.

Acoustics is designed in, not added on later

Almost every question about acoustics comes in after opening: "it's a bit noisy, how do we fix it?". It can be fixed, but that's more expensive and honestly amounts to patching a hole. Build it in at the project stage and it costs less - and it reads as design, not as a fix.

What to write in the brief: not "we want good acoustics," but "target RT60 - around 0.7 seconds at full capacity." That is a conversation with the architect in the same language - specific and measurable.

A few signals worth checking yourself:

• Estimate the RT60 in the room. If it is well above a second - there is a problem.
• On a Friday evening at full capacity, try to hold a phone call. If it is hard - the noise level is already past 78-80 dB.
• In reviews, look not for the word "noise" but for "noisy," "couldn't really talk," "somehow hectic." That is the trace of acoustics.
• Do guests regularly lean forward? That is not a posture, it is an attempt to make out the words.

At Kook - a Korean bistro in Moscow - this question came up at the design stage, not after opening. The concept dictated the materials: metal, open surfaces, energy. Already on the plan it was clear that the niche at the far end of the room would gather sound and turn into a "barrel" - a resonant trap. We decided right away: acoustic panels in that niche, following the logic of a recording studio. The K-pop theme, oddly enough, nudged us toward the right move - the studio aesthetic fit the concept organically. Fixing that niche after opening would have cost noticeably more.

And the point isn't to make it quiet. A quiet room is also a problem: empty, every word audible to the neighbours. The point is controlled acoustics. Fine dining and a lively bistro with an open kitchen should sound different, but both intentionally, not by default.

Sound as a priority is already a trend: the publication rd+d names acoustics as one of the notable themes of restaurant design in 2025, with designers increasingly bringing acousticians into the project. The market has arrived at something simple: the guest pays for a good evening, and a good evening includes how the room sounds.

Good acoustics a guest doesn't think about at all - they simply feel good, and they come back. Bad acoustics they don't think about either - they just stop coming. It's a shame to lose guests like that, blindly - especially since this is cheaper to fix than almost anything else in the room.

More material on evidence-based design is in the Insights section, including on lighting scenarios. Completed projects are in the portfolio.