DEVICELAB
AUDIOPHILE

How to use it

1. 1Install DL Audiophile from Google Play (Android 7.0 or later) and open it.
2. 2The splash screen loads your settings and any stored SPL calibration, and tells you whether SPL readings are calibrated.
3. 3Five onboarding pages follow: Welcome, Audio Analysis Suite, Device Testing, Calibrate for Accuracy and Data Export. Tap NEXT, Skip, or GET STARTED on the last page.
4. 4In regions that require it, such as the EEA and UK, Google's consent form asks how ads may use your data.
5. 5The dashboard has two sections: AUDIO ANALYSIS (12 tools that listen through the microphone) and OUTPUT TESTING (15 tools that play signals, test devices and manage results). The bottom buttons open User Guide, Tutorial and Settings.
6. 6Allow microphone access the first time you start a measurement. On Android 12 and later, the Bluetooth tools also ask for Nearby devices.

Tips

• Every measurement works offline; the internet is only used for ads and the consent form.
• Replay the dashboard tour at any time with the Tutorial button.
• Calibrate the SPL meter before you quote absolute levels.

How to use it

1. 1Pads are back-lit rubber buttons for the main action: START and PLAY are green and turn into a red STOP while running.
2. 2Keys are metal push buttons for presets and options, such as frequency presets, palettes, Reset and Clear.
3. 3LEDs show the selected option in a group, progress through wizard steps, and status lamps such as CAL on the SPL meter.
4. 4Faders slide like a mixing desk: time base, trigger level, sensitivity and volume.
5. 5Knobs turn when you drag around them, or up and down near the center. Each step gives a detent tick and the LED ring shows the position.
6. 6Seven-segment readouts show the main values; dashes mean there is no reading yet. LED ladder meters run green, then amber, then red, with one LED holding the recent peak.

Tips

• Most tools stop measuring or playing when you leave their screen.
• Switch between black anodised and brushed silver panels with Settings → Dark Finish.

How to use it

1. 1FFT Size: the Spectrum Analyzer's starting resolution, 512 to 16,384 points (default 4,096).
2. 2Dark Finish: on gives black anodised panels, off gives brushed silver. It applies straight away.
3. 3Auto Scale: the Oscilloscope opens with automatic amplitude (default on).
4. 4Show Peak Hold: the Spectrum Analyzer opens with Peak Hold on (default on).
5. 5Haptic Feedback: vibration for button presses and knob detents (default on).
6. 6Export Format: CSV, PDF or Both (default CSV).
7. 7Privacy Settings reopens Google's consent form where it is required; Privacy Policy and Terms open on strategia-x.com.

Tips

• The gear key on the Oscilloscope and Spectrogram opens Settings.
• Each tool runs at a fixed 44.1 kHz or 48 kHz; there is no sample-rate setting.

How to use it

1. 1Press START.
2. 2Time/Div fader: 100 µs to 200 ms per division (default 5 ms), with 10 divisions across the screen.
3. 3Amplitude: Auto (default) or a fixed gain from 10% to 10,000%. At 100%, a full-scale signal fills the screen.
4. 4Trigger Mode LEDs: Auto always draws and locks to a rising edge when it finds one; Normal redraws only when the signal crosses the trigger level; Single freezes on the first trigger.
5. 5Trigger Level fader: −100% to +100% of full scale.
6. 6Read frequency and period (counted from the zero crossings on screen), and Vpp and Vrms in full-scale units, where 1.000 is digital full scale.

Tips

• Set the time base so two to five cycles fit on screen.
• Use Normal or Single to freeze transients. To re-arm Single, pick another mode and then Single again.
• Vpp and Vrms are full-scale units, not volts.

How to use it

1. 1Press START.
2. 2FFT Size: 512, 1,024, 2,048, 4,096, 8,192 or 16,384 samples. It starts at the size chosen in Settings.
3. 3Scale switches the frequency axis between Logarithmic and Linear.
4. 4Peak Hold keeps the highest level at each frequency; untick it to clear.
5. 5A-Weight applies the IEC 61672 A-weighting curve.
6. 6Read Peak Freq (the strongest component above 20 Hz), Peak Level and RMS Level in dBFS.

Tips

• Resolution is 44,100 ÷ FFT size: about 86 Hz at 512, 10.8 Hz at 4,096 and 2.7 Hz at 16,384.
• Larger sizes separate close tones but update less often.
• Use Peak Hold to catch short or intermittent sounds.

How to use it

1. 1Press START.
2. 2Color Palette: Heat (default), Rainbow, Plasma, Viridis or Gray.
3. 3Frequency Scale: Log (default) or Linear.
4. 4Time Window: 5, 10, 20, 30 or 60 seconds.
5. 5Sensitivity sets the bottom of the color scale: −60, −80, −90 (default), −100 or −120 dB. The top is 0 dBFS.
6. 6Read Peak (the strongest frequency) and Level.

Tips

• Horizontal lines are steady tones such as hum, whine or resonances; vertical streaks are clicks and transients.
• A lower Sensitivity floor reveals quieter sounds; a higher one adds contrast to loud events.
• The spectrogram uses a 2,048-point FFT, about 21.5 Hz per bin.

How to use it

1. 1Press START and point the microphone at the sound.
2. 2Choose the weighting with the A, C and Z LEDs.
3. 3The seven-segment readout updates every 50 ms: cyan below 70 dB, green 70–84, orange 85–99, red 100 and above.
4. 4The LED ladder spans 30–120 dB; its peak LED holds for 2 seconds, then falls.
5. 5MIN and MAX are the lowest and highest 50 ms RMS readings, PEAK is the highest instantaneous sample level, AVG averages the dB readings and Leq is the energy average.
6. 6The reset key at the top right clears the statistics.

Tips

• With an SPL calibration stored, the CAL lamp lights and the unit reads dB SPL. Without one, it reads dB SPL (uncalibrated) and uses a typical 94 dB offset.
• A suits environmental and workplace noise, C suits loud or bass-heavy sound, and Z is unweighted.
• Readings are plain 50 ms levels; there is no Fast/Slow time weighting.

How to use it

1. 1Stand at the listening position in a quiet room, with fans and air conditioning off.
2. 2Tap Start Measurement and wait for the 3-2-1 countdown.
3. 3When CLAP NOW! appears, clap sharply once or pop a balloon. The app records 3 seconds.
4. 4Read RT60, measured over the full decay when the recording allows, otherwise estimated from T30 and then T20 as ISO 3382 describes.
5. 5EDT comes from the first 10 dB of decay; C50 (speech) and C80 (music) compare early and late energy in dB.
6. 6Results are saved to Reports automatically; Export Results shares a text report.

Tips

• RT60 under 0.3 s is very dry, 0.3–0.5 s dry, 0.5–0.8 s ideal for speech, 0.8–1.2 s ideal for music, 1.2–2 s reverberant and over 2 s very reverberant.
• A balloon pop is sharper and louder than a clap and gives a better decay.
• Measure at a few seats, not only the exact center of the room.

How to use it

1. 1Tap Start Analysis.
2. 2The app plays a 2-second broadband test signal (48 log-spaced tones from 10 Hz to 20 kHz) through the phone's output while recording the microphone.
3. 3It compares the recording with the signal against a 10 Ω reference and draws the impedance magnitude curve.
4. 4Read Fs (the frequency of the curve's peak), Zmax (its height), Re (the average below 100 Hz) and Qts, Qes and Qms (from the width of the peak).
5. 5Results are saved to Reports; Export Results shares a text report.

Tips

• The app cannot measure the voltage across and current through a driver, which a true impedance measurement needs.
• Use the figures to compare drivers measured the same way, and a dedicated impedance jig for enclosure design.

How to use it

1. 1Make sure only the speaker under test plays; the click goes to the phone's current audio output.
2. 2Hold the phone a short distance in front of it in a quiet room and tap Start Test.
3. 3The app plays a short positive-going click and records it.
4. 4Normal (In-Phase) means the strongest recorded peak was positive; Inverted (Out-of-Phase) means it was negative.
5. 5Also shown: phase difference, channel correlation, group delay (5 ms gate, 200 Hz–20 kHz) and coherence with a rating.

Tips

• A phone's own microphone path can invert polarity, so test a speaker you know is wired correctly first and use it as your reference.
• If it reads inverted, check the + and − connections.

How to use it

1. 1Press START.
2. 2Resolution chips: 1/1, 1/3 (default), 1/6 or 1/12 octave, giving 10, 31, 60 or 120 bands.
3. 3Time weighting: Fast (125 ms, default), Slow (1 s) or Impulse (35 ms rise, 1.5 s decay).
4. 4Each bar is a band level in dBFS (a full-scale sine reads 0 dB), with a peak marker that falls at 3 dB per second.
5. 5Overall Level is the power sum of all bands. Reset Peak clears the markers.

Tips

• Each band sums the power inside it, so pink noise reads flat.
• The RTA runs at 48 kHz with an 8,192-point FFT, so the narrowest 1/12-octave bands in the lowest octaves can stay empty.
• Use Slow to steady the bars for noise signals.

How to use it

1. 1Press START, then excite the room or speaker, for example with a short burst of noise or a single bass note.
2. 2Time Slices sets 20 to 100 slices of history (default 50); Clear empties the display.
3. 3The display spans 20 Hz to 20 kHz on a log axis and 0 to −80 dB; Peak shows the strongest frequency.

Tips

• Ridges that persist after the sound stops are frequencies that ring on, such as room modes or cabinet resonances.
• This is a real-time waterfall, not a cumulative spectral decay computed from a measured impulse response.

How to use it

1. 1Tap Capture IR. The status reads Waiting for impulse….
2. 2Make a sharp sound; a balloon pop is best. Capture starts when the input passes about −20 dBFS and records 3 seconds at 48 kHz.
3. 3The top chart shows the impulse response (time 0 at the peak); the second shows the Schroeder energy decay curve, 0 to −60 dB.
4. 4Read RT60, EDT, C50, C80 and Ts (center time). Pinch to zoom either chart.
5. 5Export IR shares a text summary that also includes D50, the sample rate and sample count.

Tips

• RT60 shows — when the decay is too short to measure.
• Impulse Response results are not saved to Reports, so export the ones you want to keep.

How to use it

1. 1Play a clean sine tone (1 kHz is the standard; 440 Hz also works) through the system under test, from a second device, so the phone's microphone or line input receives it.
2. 2Press START and choose Auto-detect, 1 kHz or 440 Hz.
3. 3THD combines harmonics 2 to 11 relative to the fundamental, in % and dB: green below 0.1%, cyan below 1%, orange below 5%, red above.
4. 4THD+N counts everything except the fundamental (up to 22 kHz, unweighted). SINAD is its inverse in dB, and ENOB = (SINAD − 1.76) ÷ 6.02.
5. 5The Harmonic Distribution bars show H2 to H11.

Tips

• The analysis uses a 16,384-point FFT with a 7-term Blackman-Harris window and sums each tone over its full main lobe.
• The result always includes the phone's own microphone and input stage.
• NO SIGNAL means no usable tone was found: play it louder or closer, or pick 1 kHz or 440 Hz.

How to use it

1. 1Play a steady test tone into the microphone or input and press START.
2. 2Choose Auto, 1 kHz or 440 Hz for the Signal Frequency.
3. 3Signal-to-Noise Ratio compares the tone with the noise; the tone's harmonics are left out of the noise. Green at 90 dB or more, cyan 70–89, orange 50–69, red below 50.
4. 4Signal and Noise Floor are in dBFS. Also shown: dynamic range, RMS and peak, crest factor and headroom.
5. 5The Noise Spectrum chart shows where the noise lives; pinch to zoom.

Tips

• Spikes at 50 or 60 Hz and their multiples are mains hum.
• Aim for a strong signal well below clipping, roughly −12 to −6 dBFS peak.

How to use it

1. 1Turn the Frequency knob (logarithmic, default 440 Hz) or tap a preset: 100, 440, 1K or 10K. The frequency changes live while playing.
2. 2Choose a waveform with the LEDs: Sine, Square, Triangle or Saw. White Noise and Pink Noise keys play noise instead.
3. 3Set the Output Level knob, 0–100% of digital full scale (default 50%). The phone's media volume also applies.
4. 4Sweep keys: 20–20K Hz, 100–10K Hz or Custom (one decade up from the knob). Each is a logarithmic 10-second sweep that repeats until you press STOP.
5. 5Press PLAY; it turns into STOP.

Tips

• Start at a low volume and raise it gradually.
• Generators stop when you leave their screen. For THD and SNR, play the tone from a second device.

How to use it

1. 1Choose White, Pink, Brown, Blue or Violet; a card explains the selected type.
2. 2Set the Volume slider (default 70%) and the Fade In and Fade Out times (default 500 ms).
3. 3Tap Play Noise. Changing the type while playing switches immediately.

Tips

• Pink noise has equal energy per octave and is the usual choice for speakers and rooms.

How to use it

1. 1Choose the Sweep Type: Log (default), Linear or Stepped.
2. 2Set Start and End Freq (default 20 and 20,000 Hz) and Duration (1 to 30 s, default 5).
3. 3Tap Measure. While the sweep plays, the app follows the strongest frequency and its level.
4. 4The smoothed curve is plotted on a log axis, normalised to 0 dB at 1 kHz. Pinch to zoom; Clear empties the chart.

Tips

• The curve includes the speaker, the room and the phone's microphone, so compare measurements made with the same setup and phone position.
• Frequency Response results are not saved to Reports.

How to use it

1. 1Channel Identification: L, L+R or R plays a 440 Hz tone for 2 seconds.
2. 2Frequency tests: Bass 50 Hz, Low-Mid 250 Hz, Mid 1 kHz and Treble 8 kHz, each for 3 seconds.
3. 3Full Range Sweep: 20 Hz to 20 kHz over 10 seconds.
4. 4Polarity Check: a 10 ms + Positive or − Negative pulse.
5. 5Set the Test Volume fader (default 50%). Tap a key again to stop.

Tips

• A correctly wired woofer pushes outward on the positive pulse.
• Start at a low volume to protect your speakers.

How to use it

1. 1Press START and stay quiet for a few seconds so the noise floor can be measured.
2. 2Make sounds at different levels, such as speech and a clap.
3. 3Input Level shows the current peak in dBFS (orange above −12, red above −3), and the LED meter spans −60 to 0 dBFS with a 2-second peak hold.
4. 4Read Peak and RMS, the clipping count, Noise Floor, Dynamic Range, Sensitivity and the Quality Rating.
5. 5Reset clears the results; STOP shows a summary.

Tips

• This test captures at 44,100 Hz in 32-bit float.

How to use it

1. 1Connect a loopback cable from output to input for the most accurate result, or hold the phone close to a speaker in a quiet room.
2. 2Set Number of Tests (3 to 50, default 10) and the Detection Threshold (0.01 to 1.00 of full scale, default 0.10).
3. 3Tap Start Test. Each test plays a 10 ms, 1 kHz pulse and times its arrival, up to 500 ms.
4. 4Read the latest Round-Trip Latency, Min, Average, Max and Jitter.

Tips

• Rating: Professional up to 10 ms, Excellent up to 20, Good up to 40, Acceptable up to 80, Fair up to 150, otherwise High Latency.
• No detection? Lower the threshold or raise the volume. Early triggers? Raise the threshold and quiet the room.

How to use it

1. 1Connect your Bluetooth headphones or speaker, open the tool and tap Measure Latency.
2. 2Allow microphone access and, on Android 12 and later, Nearby devices.
3. 3Hold an ear cup or the speaker close to the phone's microphone while 5 test tones play.
4. 4Read the device name, codec (SBC, AAC, aptX, aptX HD, LDAC, LC3 or Opus), sample rate, estimated latency, measured latency and confidence.

Tips

• Codec detection needs Android 13 or later and a phone that reports it. Otherwise Codec shows Unknown and the estimate assumes SBC, about 150 ms.
• Connect only one Bluetooth audio device at a time.

How to use it

1. 1Connect & Detect: read the device name, codec and estimated latency.
2. 2Measure Latency: eight test tones are timed with the phone's microphone, giving average latency, jitter, min, max and confidence.
3. 3Delay Compensation: the delay to add to your wired source in milliseconds and in samples at 48 kHz, with a table of how jitter affects phase from 50 Hz to 10 kHz.
4. 4Phase Verification (optional): record 2 seconds and analyze coherence, polarity, time offset and group-delay difference.
5. 5Final Report: a score out of 100, a grade from A to F, a verdict and recommendations. Save to Library, or share as text or PDF.

Tips

• Step 4 records with the phone's own microphones. With a mono microphone both channels carry the same signal, so coherence reads high.
• If no tone is detected, the wizard continues with the codec estimate, marked est.

How to use it

1. 1Connect the device through USB-C or an OTG adapter. The screen updates when a device is plugged in or removed.
2. 2Test Output plays a tone; Test Input reports the input level in dB.
3. 3Measure Latency plays a pulse and finds it in the recording; connect the interface's output to its input first.
4. 4Device information shows the name and the sample rates and channel counts the device reports.

Tips

• Latency rating: Excellent below 10 ms, Very Good below 20 ms, Good below 50 ms.
• Android does not expose vendor and product IDs here, so they read Not available.

How to use it

1. 1Choose Stereo (2.0), 2.1, 5.1 or 7.1.
2. 2Tap a speaker (FL, FR, C, LFE, SL, SR, RL or RR) to play a 1.5-second tone on that channel: 440 Hz, or 60 Hz for LFE.
3. 3Or tap Test All Channels to step through every channel, with each speaker highlighted in turn.

Tips

• You need an output that carries that many channels, such as HDMI or USB audio. On a stereo output, Android may mix the channels down.

How to use it

1. 1Set the Test Frequency: 100 Hz to 10 kHz in 100 Hz steps (default 1 kHz).
2. 2Left, Center and Right play the tone continuously; tap again to stop.
3. 3Tap Measure Balance. The app plays half a second on the left, then the right, and records each.
4. 4Read the left and right levels, the level difference and the twin LED meters (20 dB span).

Tips

• Within 1 dB the result reads Channels are balanced; otherwise it states which side is louder and by how much.
• Keep the phone the same distance from both sides.

How to use it

1. 1Delay Alignment: tick at least two speakers (front, center, surrounds, subwoofer or a custom label). Each is measured five times with a chirp, 200 Hz–8 kHz, or 30–200 Hz for the subwoofer.
2. 2The results table lists each speaker's delay (ms), distance (cm) and DSP Offset; the farthest speaker is the reference.
3. 3Response Matching: choose Speaker A and B and a 2, 3, 5 or 8-second sweep. You get a match score, max and average deviation, and the ranges that differ by more than 3 dB.
4. 4Phase Check: choose two speakers and a Full Sweep or Custom Frequencies (such as 60, 80, 100, 120 for a sub crossover). You get in or out of phase, coherence, polarity, time offset and a per-band grade.
5. 5Every mode offers Save to Library, Share Text and Share PDF.

Tips

• The phone sends the same test signal to its output for every speaker; it cannot address the individual speakers of a receiver or DSP. Set up your system so only the speaker being measured plays.
• Keep the phone still between measurements.

How to use it

1. 1Output and Input Devices: each device's name, type, sample rates, channel configurations and encodings.
2. 2System Audio Settings: music and ring volume, ringer mode, speakerphone, Bluetooth SCO and wired headset state.
3. 3Audio Capabilities: LED lamps for Low Latency, Pro Audio, MIDI and USB Audio, lit when the phone supports them.
4. 4Refresh re-reads everything after you connect or remove a device.

Tips

• With TalkBack, each capability lamp is announced as Supported or Not supported.

How to use it

1. 1Go to a quiet room and close other audio apps.
2. 2Switch on a sound level calibrator that plays 1 kHz at a known level, usually 94 or 114 dB SPL. Hold it snugly over the phone's main microphone, or fit it to your external measurement microphone.
3. 3Open Calibration Manager and tap Calibrate on SPL Reference Calibration.
4. 4Enter the calibrator's level (40 to 140 dB) and tap Calibrate. The app waits half a second, records 1 second and checks that the tone is within 5% of 1 kHz.
5. 5On success the card shows Calibrated with the reference level, and the Decibel Meter's CAL lamp lights with the unit dB SPL.

Tips

• No calibrator? Measure a steady 1 kHz tone at the phone's position with a trusted sound level meter and enter that reading. It is less precise.
• Recalibrate after changing phones or external microphones, after system updates, and before critical measurements.

How to use it

1. 1Microphone Calibration records 1 second and marks the card Calibrated with today's date.
2. 2Voltage Reference Calibration stores the RMS voltage you enter with a 1-second capture.
3. 3Line Level Calibration stores the professional +4 dBu (1.228 V) reference with a 1-second capture.
4. 4Reset to Default clears all four calibrations after you confirm.

Tips

• Only the Decibel Meter uses a calibration; nothing corrects frequency response from one.

How to use it

1. 1Room Acoustics, Impedance Analyzer and Phase & Polarity Tester save automatically after each measurement.
2. 2BT Alignment Wizard and Speaker Alignment Suite save when you tap Save to Library.
3. 3In Reports & Export, Share offers Export as CSV, Export as PDF or Share Report (plain text); Delete removes an entry after you confirm.
4. 4Export all in the toolbar exports every saved measurement as CSV, PDF or both.
5. 5CSV files are UTF-8 with quoted text and timestamps as yyyy-MM-dd HH:mm:ss. PDFs are A4: one measurement per page, or a title page and two measurements per page.

Tips

• No storage permission is needed: files are written to the app's cache and handed to the share sheet.
• Uninstalling the app deletes saved measurements, so export the ones that matter.

How to use it

1. 1dBFS is a digital level: 0 dBFS is the loudest signal the input can record, so real readings are negative. dB SPL is acoustic pressure and needs a calibration to be absolute.
2. 2A, C and Z weighting (IEC 61672-1): A follows the ear at moderate levels, C is nearly flat, Z is unweighted. All three read the same at 1 kHz.
3. 3Leq is the steady level with the same total energy as a varying sound over the measurement time.
4. 4FFT resolution is the sample rate divided by the FFT size: 4,096 points at 44.1 kHz give about 10.8 Hz.
5. 5RT60 is the time sound takes to decay by 60 dB, often extrapolated from T30 or T20. EDT uses the first 10 dB.
6. 6C50 and C80 compare the energy in the first 50 or 80 ms with what follows; D50 is the share in the first 50 ms; Ts is the energy-weighted arrival time.
7. 7THD compares added harmonics with the tone, THD+N also counts noise, SINAD is signal over noise plus distortion, and ENOB expresses SINAD as bits.
8. 8Typical Bluetooth codec latencies used by the app: SBC 150 ms, AAC 120, aptX 70, aptX HD 130, LDAC 100, Opus 80 and LC3 (LE Audio) 30. Real devices vary.

Tips

• +6 dB doubles sound pressure and +3 dB doubles power; 1 to 3 dB is about the smallest change most people notice.

How to use it

1. 1No audio input: check the microphone permission, close apps that use the microphone, and clean the microphone opening.
2. 2Readings jump around: reduce background noise, keep the phone still and wait 2 to 3 seconds for readings to settle.
3. 3SPL meter says uncalibrated: run SPL Reference Calibration with a 1 kHz calibrator over the main microphone.
4. 4THD or SNR shows NO SIGNAL: play the tone louder or closer, or choose 1 kHz or 440 Hz instead of Auto-detect.
5. 5No sound from generators: raise the media volume, check the active output and disable sound effects or equalizers.
6. 6Bluetooth: connect the device as media audio and allow Nearby devices on Android 12 and later.

Tips

• Clearing the app's storage or reinstalling deletes saved measurements and calibrations.
• Still stuck? Email support@strategia-x.com with your phone model and Android version.