For live sound crews, churches, schools, bands, and music students
PA and band sound checks, all in one iPhone app
Find feedback-prone frequencies, check which speaker is left or right, listen for reversed polarity, record rehearsals in stereo, and review band timing. Check1.2 brings practical live sound and music practice tools together on your iPhone.
Get Check1.2 free on the App Store
Watch: find feedback frequencies with just your iPhoneOpens on YouTube.For the moments before the show, after rehearsal, and during practice
Before doors open: use Monitor check to see the frequencies most likely to feed back, in Hz, while you ring out a stage monitor.
At soundcheck: play Left, Right, Center, and reversed polarity to check speaker routing and listen for a polarity mismatch. The listening check is free.
After rehearsal: record stereo audio and review timing changes in a song. Use markers to split a recording into sections and export a PDF timing report.
For music practice: tune drums, use the Tuner and Metronome, and train your ear with frequency quizzes and Daily Ear Training.
Tools for live sound and music practice
Monitor check: use the iPhone's built-in mic to find frequencies likely to feed back. Keep 3 results free; the Full version stores unlimited results and lets you compare visits to the same venue.
Analyzer and spectrogram: view audio frequencies from 50 Hz to 18 kHz. The spectrogram is available free 3 times a day; the Full version removes that limit.
Speaker check: play Left, Right, Center, reversed polarity, and a frequency sweep. Listen to confirm left/right routing and compare polarity by ear. The Full version's mic measurement checks speaker output, left/right assignment, and polarity in about 6 seconds from the audience area.
Stereo recording: capture audio without compression or limiting. Free stereo recordings are up to 5 minutes each, with 2 saved recordings. The Full version allows longer recordings and unlimited saved recordings. Supported formats include m4a and WAV. You can keep music playing while you record, and stop recording from the Lock Screen or by long-pressing the Dynamic Island.
Video recording: combine camera video and stereo audio in one clip. The original audio file is also kept. Available in the Full version and during its trial.
Band timing check: set a target tempo for each song, compare with a previous take, listen to marked sections, and export a PDF report. Available in the Full version and during its trial.
Drum tuning guide: check the pitch of snare, tom, and floor tom taps, then follow guidance on which tension rod to adjust.
Ear training: the Frequency quiz has two free Beginner sets a day. Daily Ear Training is free once a day: 6 single-tone questions and 4 A/B comparisons. Sign in to Game Center to join the daily ranking.
Also included: Voice profile, Tuner, and Metronome. The Analyzer and Voice profile have no time or use-count limit.
Guides
Free download. Optional one-time Full version.
Free: download at no cost. Core tools include Monitor check, Analyzer, Voice profile, Metronome, Tuner, Speaker check by ear, and the free portions of recording and ear training. No account required.
Full version: $6.99 as a one-time in-app purchase on the U.S. App Store (October 2026), not a subscription. It unlocks features including mic-based speaker measurement, unlimited saved Monitor check results, longer stereo recordings, video recording, and Band timing check. Regional prices may differ and prices can change; check the App Store.
7-day free trial: try Full version features for 7 days. After the trial, you can choose whether to buy. If you do not buy, the app returns to the free version and you are not charged.
Common questions
Does Check1.2 stop feedback or change my EQ? No. It shows frequencies that may be prone to feedback. You decide what to change on your mixer and sound system.
Do I need an external mic? No. Monitor check and mic-based checks use the iPhone's built-in microphone.
Is the Full version a subscription? No. It is a one-time in-app purchase. The 7-day trial does not automatically charge you when it ends.
Can I use it for a band or school ensemble? Yes. Use Band timing check for rehearsals, the Tuner and Metronome for practice, and live sound checks when setting up a PA system.
Which devices are supported? iPhone with iOS 17.0 or later and iPad with iPadOS 17.0 or later.
Is it a calibrated measuring instrument? No. Check1.2 is a practical checking aid, not a calibrated measuring instrument. Results can depend on the room, speakers, and setup.
Your recordings and results stay on your iPhone
The app privacy label states that data is not collected. Recordings, analysis, Voice profile, results, and venue notes stay on your iPhone. The app connects to Apple for in-app purchases.
Make your next soundcheck easier
Start with the free speaker listening check or use Monitor check while ringing out a wedge. Install Check1.2 and try the tools at your next rehearsal or show.
Get Check1.2 free on the App Store