Making invisible acoustic problems visible
"You know how a room changes the way speakers sound? Like, the same speakers can sound amazing in one room and terrible in another — boomy bass in one spot, no bass in another, weird echoes. Most people just accept it, or they move their couch around randomly hoping it gets better.
SonarRoom figures all of that out with just your iPhone. You connect your phone to your speakers, hit start, and walk around the room for about three or four minutes. The app plays a test tone through your speakers and records what the microphone picks up. At the same time, it's using the phone's camera and AR to scan the room and track exactly where you are.
When you're done, it builds this 3D map of your room showing how the sound changes everywhere. You can rotate it around and see — here's where the bass builds up, here's where it disappears, here's the sweet spot where everything sounds the best.
But the really cool part is that it doesn't just show you data — it tells you what's wrong. It'll say 'you have a standing wave at 204 Hz causing a 20 dB peak' or 'there's a null at 129 Hz where the bass just disappears.' It explains what each problem is in plain English, shows you where it is in the room, and rates how severe it is.
Basically, it makes invisible acoustic problems visible. And once you can see them, you can actually do something about them."
SonarRoom is an iPhone app that turns your phone into a room acoustics analyzer. You play a test tone through your speakers, walk around the room holding your phone, and the app builds a 3D map showing exactly how sound behaves at every point in the room. It tells you where the best listening spot is, where the bass disappears, where echoes cause problems, and what you can do about it.
Most people who care about audio — whether they are mixing music, watching movies, or listening to their favorite album — have no idea that the room they are sitting in dramatically changes what they hear. A flat pair of speakers can sound completely different depending on where they are placed and where the listener sits. Bass frequencies double in volume in some corners and completely disappear in others. Reflections off walls create echoes and interference patterns. Stereo imaging collapses if the listener is off-center.
Professional studios spend tens of thousands of dollars on acoustic measurement and treatment. SonarRoom brings that measurement capability to anyone with an iPhone and a speaker system. It doesn't just show a frequency response chart — it shows where in the room the problems are, making the invisible visible.
Acoustic problems are invisible, spatial, and non-uniform. Sound behaves differently at every point in a room. A single measurement at a single position reveals almost nothing about the room as a whole. SonarRoom's core innovation is that it measures many points across the room and maps the results in 3D space, making spatial acoustic patterns visible for the first time on a consumer device.
Operating bedroom studios, project studios, or semi-professional recording spaces. If your mixes translate poorly to other systems, SonarRoom identifies room modes affecting mix decisions, finds the flattest monitoring position, and quantifies the problem so you can prioritize treatment.
Invested in high-quality playback equipment but unsure why it underperforms? SonarRoom quantifies how much the room is limiting your system, guides speaker and listener positioning, and provides data-driven treatment recommendations.
Running 2.1, 5.1, 7.1, or Dolby Atmos systems and dealing with subwoofer placement problems — boomy in one seat, thin in another. SonarRoom maps bass distribution across the room, finds the best sub position, and identifies problematic seats.
Recording in untreated rooms? RT60 mapping and clarity metrics help identify the best recording position in a room, so you get the driest, clearest capture without expensive booth construction.
Anyone who wants to understand why their room sounds the way it does. The scoring and visualization make complex acoustics accessible — no acoustics degree required.
Give your room a name, select your speaker layout (Stereo, 2.1, 5.1, 7.1, Atmos, or custom), and choose your playback mode. For stereo systems, play test tones directly from your phone. For multichannel surround systems, SonarRoom generates a multichannel WAV test signal file (up to 16 channels) that you export to your AVR or media server. If you have a USB measurement microphone, plug it in — the app detects it automatically and applies calibration. SonarRoom runs a quick latency calibration (with wireless-aware warm-up for Bluetooth and AirPlay) to ensure precise synchronization.
Hit start and walk around your room for 3–4 minutes. SonarRoom does everything simultaneously: scans the room geometry with AR, plays test tones through your speakers (or listens while your AVR plays the exported multichannel WAV), records the microphone response, and tracks your position in 3D space. A live coverage map shows your progress — aim for 90%+ coverage. Point the camera at each speaker and tap to place them in the 3D model. Per-sweep quality monitoring flags any noise contamination or transient events in real time.
When you stop, SonarRoom processes the audio — extracting impulse responses via adaptive Wiener deconvolution with per-bin SNR-adaptive regularization, rejecting harmonic distortion pre-echoes, applying device-specific or imported microphone correction, computing frequency response with Tukey and frequency-dependent windowing per octave band, analyzing reverb and reflections, and building a spatial acoustic map. When multiple sweeps overlap at similar positions, they are coherently averaged in the complex domain to reduce noise and compute per-frequency coherence. Hundreds of measurement points are processed and interpolated into a continuous volumetric grid covering your entire room.
Get an overall quality score (0–100), detailed per-category breakdowns, an interactive 3D heatmap, frequency response charts, spectral decay plots, a ranked sweet spot list, and a prioritized problem report — all from a single measurement walk.
How loud each frequency is reproduced at every point in the room. A flat response means accurate sound. SonarRoom reveals peaks (frequencies that are too loud — often caused by room modes) and dips (frequencies that disappear — caused by cancellation). Multi-point overlay shows which issues are room-wide versus position-dependent.
When multiple sweeps are captured at similar positions, the app performs coherent complex-domain averaging and computes coherence at each frequency — a 0-to-1 measure of how repeatable the measurement is. High coherence means the data is reliable; low coherence flags frequencies dominated by noise or room variability. Confidence bands on the frequency response chart show exactly where you can trust the measurement and where to be cautious.
How long sound takes to decay after the source stops. Too much reverb makes music muddy and speech unintelligible. Too little makes the room sound unnaturally dead. SonarRoom measures RT60 per octave band and maps how reverb varies with position — areas near reflective surfaces tend to be more reverberant than areas near absorption.
How well the direct sound dominates over the reverberant tail. High clarity means you hear individual notes and lyrics distinctly. Low clarity means everything blurs together. C50 is optimized for speech; C80 for music.
How symmetrically the left and right speakers are reproduced at each position. Imbalance causes the phantom center image to shift and degrades stereo separation. SonarRoom measures L/R differences across the room and shows where the balance tilts.
How sound pressure level varies across the room. Reveals whether certain areas are dramatically louder or quieter than others — a hallmark of room mode interference patterns.
A time-frequency view showing how energy at each frequency fades after the sound stops. Reveals bass frequencies that ring out much longer than others — the cause of "one-note bass" where all bass notes sound the same. Interactive controls let you adjust time range, frequency range, dynamic range, and slice count. Ridge line visualization and room mode overlays highlight persistent resonances.
Each sweep is individually assessed for quality: ambient noise gating verifies the noise floor was acceptable, transient detection flags door slams or other impulsive events, and per-sweep SNR measures signal strength relative to noise. This metadata helps identify unreliable measurements and ensures recommendations are based on solid data.
SonarRoom doesn't just present raw data — it interprets your measurements into named, explained issues that you can understand and act on. Each problem includes a plain-language explanation, severity rating, affected frequency range, 3D visualization of the affected area, and related treatment recommendations.
When room dimensions create resonant frequencies, sound reinforces itself at certain positions. The result: specific bass frequencies are dramatically louder than they should be. SonarRoom identifies the exact frequencies and shows where in the room the peaks and nulls occur.
Destructive interference causes certain frequencies to nearly disappear at specific positions. Unlike peaks, nulls can't be fixed with EQ — you need to change the physical setup. SonarRoom shows exactly where they are so you can move your listening position or speakers to avoid them.
Rapid repeating echoes between parallel reflective surfaces — bare walls, hard floor and ceiling. Sounds like a metallic "ping" after sharp sounds. SonarRoom identifies the surfaces responsible and the fundamental frequency of the flutter.
A strong reflection arriving at a consistent delay creates periodic cancellation across the spectrum. The result is a "hollow" or "phasy" sound quality. SonarRoom detects the harmonic pattern and identifies the reflection causing it.
When a speaker is near a wall, the direct sound and the reflected sound cancel at specific frequencies determined by the distance. SonarRoom knows your speaker positions and wall distances, predicts where SBIR should occur, and confirms it in the measurements.
If the left and right speakers produce significantly different levels at the same position — due to asymmetric placement, room geometry, or surface differences — SonarRoom flags the imbalance and quantifies the difference.
SonarRoom translates complex multi-dimensional acoustic data into a single actionable score from 0 to 100. You don't need to understand what RT60 means to see that your room scored 34 on bass and 100 on reverb — you immediately know bass is the problem.
A weighted combination of all category scores. 76–100: Excellent — well-controlled acoustics. 51–75: Good — moderate issues, room is usable but could benefit from treatment. 26–50: Fair — significant issues with noticeable coloration. 0–25: Poor — severe acoustic problems actively undermining audio quality.
Six individual scores break down exactly where the room excels and where it needs work: Frequency Response (overall accuracy), Bass (low-frequency behavior and room modes), Stereo Balance (L/R symmetry), Reverb (RT60 quality), Clarity (early vs. late energy), and Sweet Spot (quality of the best listening position).
Instead of asking you to guess where to sit, SonarRoom evaluates every position in the room and computes a composite quality score based on frequency response flatness, stereo imaging accuracy, reverb consistency, and bass energy balance.
The app identifies and ranks the top 3 listening positions, showing each one as a marker in the 3D room view — gold for the best, silver for second, bronze for third. Each sweet spot includes a quality score, position coordinates, and a radius showing how far you can move before quality degrades significantly.
If no position in the room achieves an acceptable quality threshold, the app tells you honestly — your room has no sweet spot, and the problems list will explain why.
SonarRoom presents your acoustic data through multiple interactive views:
SonarRoom adapts to your device's capabilities:
Full RoomPlan scanning with classified surfaces — walls, floor, ceiling, doors, windows, and furniture with centimeter accuracy. Best spatial precision for speaker placement and room mode prediction.
Monocular depth estimation provides room geometry with slightly reduced accuracy. Wall positions may be off by 5–10 cm — but acoustic measurement doesn't require centimeter precision. Sound wavelengths at bass frequencies are meters long, so the acoustic data is just as valid.
iPhone microphones aren't flat — every model has a different frequency response. SonarRoom includes built-in correction curves for iPhone XS through iPhone 17 Pro Max and iPad Pro/Air/mini models (2020–2025), automatically compensating for your specific device's microphone characteristics.
For professional-grade accuracy, plug in a USB measurement microphone. SonarRoom automatically detects external inputs and includes built-in generic profiles for popular mics: miniDSP UMIK-1/UMIK-2, Dayton Audio UMM-6, Behringer ECM8000, and Sonarworks XREF 20. You can also import per-mic .cal or .frd calibration files for maximum accuracy. The app classifies inputs by priority (USB > Wired > Built-in > Bluetooth) and allows manual input selection with locking to prevent auto-switching during measurement. Bluetooth HFP mics are supported but flagged as lower quality.
SonarRoom is a powerful spatial acoustic survey tool, but it's important to understand what it is and what it isn't:
SonarRoom is under active development. Some features we're working toward:
The acoustic "fingerprint" of a room at a specific position. It describes how the room modifies any sound — including the direct sound, all reflections, and the reverberant decay. All other metrics are derived from the impulse response.
A graph showing how loud each frequency is reproduced at a given point. A flat frequency response means all frequencies are equally loud — the goal for accurate sound reproduction.
A stationary interference pattern created when sound bounces between parallel surfaces at a frequency related to the surface spacing. Creates fixed zones of dramatically louder and dramatically quieter bass. The most common acoustic problem in small rooms.
A frequency that nearly disappears at a specific position, caused by destructive interference — two sound waves arriving out of phase and canceling each other. Cannot be fixed with EQ; only by changing the physical setup.
Reverberation Time 60 — how long (in seconds) it takes for sound to decay by 60 dB after the source stops. Measures how "live" or "dead" a room is. Ideal for music listening: 0.3–0.5 seconds.
The position in a room where acoustic quality is best — flattest frequency response, best stereo imaging, most controlled reverb, and highest clarity. Where you should sit.
Speaker-Boundary Interference Response — cancellation caused by the interaction between the direct sound from a speaker and its reflection off a nearby wall. Creates a dip in the bass response at a frequency determined by the speaker-to-wall distance.
Sound Pressure Level — a measure of how loud a sound is, expressed in decibels (dB). Higher SPL = louder.
A rapid series of repeating echoes caused by sound bouncing between two parallel reflective surfaces. Sounds like a metallic "ping" or buzzing after a sharp sound like a clap.
A measure of how repeatable a measurement is at each frequency, ranging from 0 (completely unreliable) to 1 (perfectly consistent). Computed by comparing multiple sweeps at the same position. High coherence means the data is trustworthy; low coherence indicates that noise, room variability, or measurement error is dominating at that frequency. SonarRoom uses coherence to weight problem detection and EQ generation — unreliable frequencies are automatically de-emphasized.
How long different frequencies take to arrive at the listening position, measured in milliseconds. Ideally all frequencies arrive at the same time (flat group delay). Large variations in group delay cause time smearing — bass arriving noticeably later than treble — which degrades transient clarity and imaging. Derived from the unwrapped phase response.
The mathematical process of extracting a room's impulse response from a recorded sweep. SonarRoom uses adaptive Wiener deconvolution — a technique that adjusts its noise suppression per frequency based on estimated signal-to-noise ratio. Frequencies with strong signal get minimal processing (preserving detail), while noisy frequencies get heavier smoothing (suppressing artifacts).
Hi, I'm Craig Cowden, the creator of SonarRoom.
I built SonarRoom because I care deeply about how audio actually sounds in real spaces — not just the gear, but the room itself. Speaker placement, reflections, and room shape can dramatically affect what you hear, and most people don't have access to tools that make those problems easy to understand.
SonarRoom was created to make room acoustics more accessible using the device you already have in your pocket. It's designed to be practical, technically meaningful, and easy to use — whether you're setting up a home theater, studio, or just trying to get better sound out of your space.
This is an independent project, built and maintained by me. I'm focused on creating tools that are useful, honest, and respectful of the people using them.
Privacy matters. SonarRoom processes all scans and analysis directly on your device. The app does not upload, store, or share your room data — everything stays on your phone.
If you have questions, feedback, or run into any issues, I'd genuinely like to hear from you.