Last updated: Nov. 1, 2022

BeatMirror detects tempo in real-time using your iPhone or iPad’s built-in microphone. Check out BeatMirror in action below and then scroll down to learn more:

1. Get your device ready.

1. Disconnect headphones/mics. Disconnect any external headphones or microphones to start. That ensures that the device’s built-in microphone will be used.
2. Put your device down. Actively handling the device can cause your hand to accidentally rub against the microphone, adding noise to the incoming audio and reducing detection quality. You’ll get your best performance if the device is somewhere where it won’t be moved around.
3. Avoid competing noise. Keep your device away from competing noise sources. You’ll get the best tempo detection if the device has nice, clear, noise-free music to listen to. So be wary of loud talking or other sounds near the device.

2. Pick a target tempo.

The target tempo is often used by musicians who are trying to play music at a specific tempo. If you’re detecting music from a recording, you can just tap out a few beats on the tap pad to get your target, as shown below.

The target tempo can be changed before or during detection. If changed during detection, your tempo history is reanalyzed using the new value.

There are five ways to set the target tempo quickly and easily.

1. Dragging. You can tap and hold the target tempo button, dragging up or down, to set the target tempo. For small changes (e.g., ±1 bpm), drag your finger slightly; for larger changes, drag your finger farther away and the tempo will change more quickly.



NOTE: If you’re making a big change to the target tempo, it can be helpful to drag your finger twice: once to get “in the ballpark” and the second to hone in on an exact value.

2. Tempo keyboard. Tap the target tempo button to reveal the tempo keyboard. Type in a tempo between 40 and 208 bpm.



3. Tap pad. Start tapping on the pad to set the target. Tap outside of the pop-up window to close the keyboard and confirm the new tempo.



4. +/- buttons. If tapping doesn’t give the exact value you’re looking for, use the +/- buttons to adjust the target tempo in ±1 bpm increments.



5. Roll the dice. To get a random tempo, tap the dice button. 🙃

3. Select a count-in value.

The count-in feature plays the selected number of clicks before detection starts, in addition to displaying the count-in on screen. This is particularly useful for musicians who want to get the tempo “in their head”—and their hands on their instrument—before beginning to play.

1. Open menu. Tap the “Count-in” button to select the number of count-in beats (or None).



2. Choose value. Selecting “4” would be the most common choice for musicians playing in 4/4 time. If you’re detecting tempo from a recording instead, you’ll likely want to select “None.”

4. Select visual feedback.

If you’re a musician trying to bring your tempo into the target range, it can be helpful to turn on visual feedback. A coloured highlight will show you at a glance if you’re playing too fast, too slow, or just right. Toggle the feedback feature on or off at any time.

1. Toggle feature. Tap the button in the top-left of the graph to toggle this feature on and off.



2. Detect slow/fast tempo. When enabled, the visual feedback feature will show a blue highlight when you are playing too slow and a red highlight when you are playing too fast. Thresholds for “too fast” and “too slow” are ±2% away from the target.

   

3. Detect in-range tempo. A green highlight will show when you’re close to the target (within 2%):

   

5. Detect tempo (bpm)

Once you’re ready, tap the big start button to begin. Many different features can be accessed during detection, as explained below.

1. Start. Tap the big start button to begin tempo detection. Tap it again at any time to pause detection.



2. View tempo. As tempo is detected, the beats-per-minute (bpm) value will be displayed a) as a big number at the top of the screen, and b) by the graph’s tempo marker (i.e., the dot with surrounding circles). When enough data comes in, the graph will automatically scroll.



3. Scroll graph. You can manually scroll the graph during detection or when paused to review the tempo history. To resume auto-scrolling, either scroll the graph all the way to the tempo marker (i.e., drag your finger to the left) or tap the resume button:



4. Zoom graph. Tap the zoom button (or double-tap the graph) to select from three zoom options: tight, loose, and full. Tight and loose zooming will auto-scroll when the tempo marker approaches the edge of the graph. Full zooming will periodically re-zoom to ensure all collected data is displayed. (See demo)



5. Reset graph. Reset the graph at anytime. If the graph is reset during detection, detection will restart immediately.



6. Full-screen graph. If using an iPhone, turn your phone to landscape to maximize the graph.

6. Supplementary features

BeatMirror offers several other options to help support your tempo detection needs.

1. Input level. The level (i.e., volume) of incoming audio is shown on the level indicator during detection. The level indicator can be found in the bottom-left corner of the screen.
• If the level indicator does not change during detection, see “7. Troubleshooting” below.
• If the level indicator shows very high levels (e.g., all five bars frequently lit), the audio may distort and affect tempo detection. Consider reducing the volume of your music source, if possible, or moving the device farther away.



2. Screenshot button. Save or share an image of the graph by tapping the camera button. (See demo.)



3. Algorithm selector. Toggle between the standard BeatMirror “hand” algorithm and the new “ear” algorithm, which may be better suited for music with more background noise, e.g., live performance. (See demo.)

7. Other options

The top menu items offer options to get in touch with the developer (me) directly or to view the tutorial.

1. Tutorial. Tap the tutorial button to begin an in-app tutorial.



2. Contact us. To send us an email from your device, tap the contact button. You can also send us a note through the “Contact us” form at the foot of this page.

8. Troubleshooting

Any issues should be resolved by following these four steps. That said, please don’t hesitate to contact us if you’ve tried them all but are still experiencing issues.

1. Verify setup. Ensure you’ve prepared your device for optimal collection (see Step 1). To verify that the audio is coming through clearly, try recording a quick sample using the Voice Memos app and take a listen.
2. Check mic input. During detection, tap the microphone on your device (e.g., on the bottom of an iPhone) and ensure that the level indicator responds.
   
   If it doesn’t respond, that could mean that an external microphone is being used (connected via cable or Bluetooth). Disconnect it and try again.
3. Check music. Ensure there is a clear beat to your playing. If you can tap your foot to the music, then BeatMirror should be able to detect the tempo; if you have trouble hearing a beat, then this could be the issue. To see if this is the problem, try BeatMirror with a metronome.
4. Reinstall BeatMirror. Not the most satisfying solution, but a quick reinstall can reset any audio permissions/conflict strangeness that might be behind the issue.

Questions, comments, or feature requests? Get in touch any time using the “Contact us” form below.

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