Comparison

Under FM vs HangSpine

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Under FM

Enhance your listening experience by layering background music or beats under podcasts and audiobooks. Adjust volume and tempo to create the perfect ambiance for workouts, chores, or focused work.

Highlights
  • Background beats under podcasts/audiobooks
  • Standalone music playback
  • Adjustable tempo and volume
  • Lock Screen controls
  • Favorites and recent tracks
  • No account required
Features
Read full description

Under FM lets you listen to music and a podcast at the same time. It plays background beats under podcasts and audiobooks, or on their own. Add background music to podcasts while running, walking, cycling, lifting, cleaning, working, or getting through anything that feels better with a beat. Your podcast or audiobook keeps your mind engaged while the music adds energy and rhythm. Start any podcast or audiobook, open Under FM, and choose a beat. Lower the beat volume until it sits beneath the voices, then adjust the tempo to match your pace. Use Under FM for podcast background music, audiobook background music, podcast beats, or simply playing music and spoken audio at the same time. The spoken audio stays clear. The beat stays underneath it. You keep listening without giving up the energy of music. Choose from beats for easy movement, steady sessions, and higher-energy workouts. Save the beats you like, revisit recently played tracks, and control playback from your Lock Screen. Features: • Background beats that play under podcasts and audiobooks • Standalone beats when you want to listen without spoken audio • Adjustable tempo and BPM • Independent beat volume control • Lock Screen playback controls • Favorites and recently played beats • No account or sign-in required • No ads • Free beats, with more available to unlock Use Under FM for: • Background music for podcasts • Music under podcasts • Podcast beats for running and workouts • Audiobook background music • Music and podcasts at the same time • Music and audiobooks at the same time • Running, walking, cycling, lifting, cardio, chores, and focused listening Start your podcast, open Under FM, choose a beat, and keep moving. Privacy Policy: https://www.maurs.com/underfm/privacy Terms & Conditions: https://www.maurs.com/underfm/terms

About

HangSpine

Features
Read full description

HangSpine turns your Apple Watch into a dead-hang counter. Grab the bar and just hang — your watch's motion sensors detect the hang automatically and start the count for you. No buttons mid-workout, no phone needed. Every 10-second hold counts as one rep, confirmed by a haptic tap so you always know where you stand. WHY DEAD HANGS Dead hangs decompress the spine and shoulders after long hours at a desk, build grip strength, and stretch the whole upper body. A few minutes on the bar is one of the simplest full-body resets you can do. SMART DETECTION THAT ADAPTS TO YOU • Hang detection runs on the watch's gyroscope — mount the bar and the countdown starts by itself; dismount and it stops • Set your own pace: 10/12/15 s per rep and a daily goal you choose • An experimental on-device learning engine keeps learning your mount and dismount motion, so detection gets more accurate the more you train — no two bodies or bar setups are alike, and HangSpine adapts to yours. It's continuously improved and never affects everyday counting • Everything is computed and stored locally. Nothing is ever uploaded for training ON YOUR PHONE • Today's goal ring, streak flame, and day/week/month/year charts • 26-week GitHub-style heatmap of your training consistency • Trace viewer for every session: angle, X/Y/Z gravity components, and grip energy — see exactly what the sensor saw PRIVACY BY DESIGN All data stays on your devices. No account, no tracking, no ads, no servers. One-time purchase. No subscription.

Screenshots

Under FM4 screens
HangSpine4 screens

Verdict

The call

The clearest difference is price: Under FM at Free against HangSpine's $5.99. HangSpine's advantage is in-app purchases (none vs 2) and update cadence (daily vs every 3 days). On ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Under FM is free to download; HangSpine costs $5.99 up front. Under FM sells 2 in-app purchases, starting at $9.99 per year. HangSpine asks for nothing beyond the download.

UpkeepUpdate frequency

Under FM ships an update every 3 days, HangSpine daily. Both last shipped on October 31, 2026.

Scorecard4 real differences · 6 level
Under FM versus HangSpine: the parameters behind the verdict, then further details
ParameterUnder FMHangSpine
PriceFree — better$5.99
Rating5.0 (7 ratings) — better—
Positive reviews100.0% of reviews—
Number of ratings7 — better—
Update frequencyEvery 3 daysDaily — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhoneiPhone, Apple Watch — better
Requires iOS18.616.0 — better
Further details — not scored
Size87 MB4 MB
Age rating4+4+
DeveloperEnterMaurs永鹏 梁

In-app purchases

2 purchases

Under FM

Subscriptions1
  • Under FM Pro Annual$9.991 Year
One-time1
  • Under FM Pro Lifetime$14.99
None

HangSpine

No in-app purchases

Questions

Is Under FM free?
Under FM is free to download, with in-app purchases available.
Is HangSpine free?
HangSpine costs $5.99, with no in-app purchases.
Do Under FM or HangSpine have ads?
Neither Under FM nor HangSpine shows ads.
Which is updated more often, Under FM or HangSpine?
Under FM ships an update every 3 days, and HangSpine daily. Most recently, Under FM was updated on October 31, 2026 and HangSpine on October 31, 2026.

Other comparisons