app
Spectrum analyzer for iPhone — dB Pulse Pro
dB Pulse Pro includes a spectrum analyzer with a freeze workflow, crosshair readout and bass, mid and treble summaries. It helps inspect frequency content from the microphone, rather than providing a certified acoustic spectrum or a diagnosis of what caused a sound.
Swipe to see the full table →
| Question | What to know |
|---|---|
| Plan | Pro spectrum interaction and analysis. |
| Useful view | Approximate frequency-band content and broad bass/mid/treble summaries. |
| Hold state | A frozen chart is a captured display, not ongoing sound. |
| Not claimed | Certified octave-band measurement or calibrated band SPL. |
Open the frequency view
From Tools, choose Spectrum Analyzer. The Pro feature displays frequency bands from the microphone signal, alongside a dominant-frequency indication. Start with ordinary ambient sound at a comfortable level; you do not need to generate a loud tone to make the display meaningful.
The ordinary decibel meter summarizes overall level. A spectrum offers another view by showing how signal content is distributed across frequency bands. A low-frequency hum can look different from a sharper hiss even when the overall reading is similar. That distinction can help frame a better question about the sound.
Use the crosshair and freeze controls
The feature is designed to let you hold the chart and inspect a selected band with the crosshair. Look for the Frozen indicator when using the hold interaction, and distinguish a held display from a changing live input. A frozen chart represents the captured display state rather than sound that continues forever afterward.
The crosshair’s frequency labels are approximate, and the displayed magnitude is not a certified dB SPL value for that band. Do not read a relative percentage as a physical sound-pressure level. The source’s bass, mid and treble summaries are convenient groupings rather than a claim of standards-compliant octave-band analysis.
Change one condition at a time
If you are comparing a fan with a door open and closed, keep the phone in the same position and use the same input. Note whether the change affects the low bands, high bands or overall level. Move the phone only in a separate comparison, otherwise the source change and position change are mixed together.
Room reflections, nearby surfaces and the microphone’s own response influence the shape. A strong band can suggest a useful place to investigate, but it does not prove a component is faulty or identify a specific machine through a wall. Corroborate the observation using the source’s operating state and, where needed, an appropriate instrument.
Use generated tones gently
The browser tone generator can be useful for learning how a changing pitch relates to the frequency display. Keep playback low, avoid wearing headphones for any improvised microphone calibration and stop immediately if the sound is uncomfortable. Never increase an inaudible high-frequency tone just to force a visible response.
A generated digital frequency is not a calibrated acoustic level. The loudspeaker, room and device gain affect what reaches the phone. Use real calibration equipment when a physical reference is required.
Choose the right scope
Spectrum Analyzer is a Pro feature; free users can still use the live meter and other included tools. For a broad before-and-after soundproofing check, the separate Acoustic Test workflow may be more relevant than inspecting one frequency band.
Neither workflow measures hearing ability or supplies certified laboratory results. The analyzer is useful for exploration and repeatable informal comparisons, with those microphone and display limitations kept visible.
Sources
Phone and browser readings are estimates. For formal decisions, use the specified equipment and procedure; see the accuracy notes.
Try the next check
Online tone generator can help with this question. See the matching dB Pulse feature.