# SDC – Sub Delay Checker — stop guessing-start measuring

> stop guessing-start measuring (iPhone/iPad app by frank Barsch.)

- Source: https://appshunter.io/ios/app/sdc-sub-delay-checker/id6808641772 (this page in markdown: same URL + `.md`)
- Developer: [frank Barsch](https://appshunter.io/developer/6808641774)
- Category: Music, Utilities
- Price: $3.99
- Age rating: 4+
- Requires: iOS 16.0 · 4 MB
- Languages: American English
- Released: 2026-09-13
- Data updated: 2026-10-23

## What is SDC?

stop guessing - start measuring.

you are a touring dj or a sound engineer on a tight schedule and a tighter budget.
sdc gets your subs and tops aligned with the gear you already carry.


WHAT YOU NEED

- iPhone, iPad or Mac
- an audio interface, or the usb card already in your mixer
- a measurement microphone

run the output and the microphone through the same interface. that shared sample
clock is what makes the timing trustworthy, and sdc warns you when the two don't
match. a built-in phone mic is fine for a rough look - a measurement mic on one
shared clock is what you want when it counts.


HOW IT GOES

1. hook it up and pick your input and output channels
2. hit start - a level check runs first so you can set your gain
3. the app walks you through it: mute the sub and it measures the top,
   mute the top and it measures the sub
4. read the answer


WHAT YOU GET

not a chart to interpret. a sentence to act on:

   "increase sub delay by 0.8 ms to reach phase alignment at 100 Hz"

and the numbers behind it: arrival times for top and sub, the difference in
milliseconds and in metres, how far the phase is off at your crossover, and how
high up the two stay inside the 60 degree corridor. tell sdc if your dsp or sub
runs a 180 degree polarity flip and it aims at the right target angle.

set the value on your mixer or dsp. done.


THE ROOM, IF YOU WANT IT

after a measurement you can add a room sweep to the same export. sdc plays a
reference sweep, records the response, and hands you both files as a
stimulus/response pair for whatever analyser you already use.
no analysis happens in the app - that part stays in your tool.

for sweeps, use an interface. a phone's built-in speaker and mic don't share a
tight enough clock, and the recording gets rejected on import.


BUILT FOR THE FIELD

- a guide inside the app: signal chain, mic position and height, the full workflow
- an ear protection warning before anything loud plays
- works with what you have: usb interfaces, mixer usb cards, wired measurement mics


YOUR DATA STAYS YOURS

no account, no network, no tracking, no ads. every export lands on your device
and goes nowhere unless you send it yourself.

## Is SDC safe?

Not enough ratings yet to assess SDC.

## Is SDC legit?

SDC – Sub Delay Checker has limited verification signals. The AppsHunter Legitimacy Score for SDC is 58 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 4 releases)

### 1.1.1 — 2026-10-14

What's new in 1.1.1

• Fixed: the "Current Sub delay" field and the recheck entry are now clearly readable in dark mode.
• Crossover preview: live curves of low-pass, high-pass and their sum, including the entered delay. Drag inside the chart to set the crossover frequency.
• Measured curves appear dashed over the preview after each measurement step.
• Recheck: after dialling in the recommended delay, only the adjusted side is measured again.
• Guided flow: muting tips, a level check that continues once the input is green, and a "Measurement OK?" step that saves the result and offers the room sweep.
• Warning when the level at the crossover frequency is too low for a reliable phase reading.

### 1.1.0 — 2026-10-09

New in 1.1.0

• Crossover preview: see your crossover frequency, filter and delay as a live curve — low-pass, high-pass and, most importantly, their summed response. Drag inside the chart to set the crossover frequency.
• Measured curves on top: after each measurement step, the measured response of Top and Sub is drawn over the preview, so the setting sits right next to what the system actually does.
• Recheck: after dialling in the recommended delay, only the adjusted side is measured again — the other side stays as reference. Rooms usually need two or three rounds.
• Guided flow: muting tips before each measurement, a level check that only continues once the input is in the green, and a clear "Measurement OK?" step that saves the result and offers the room sweep right after.
• Room-mode warning when the level at the crossover frequency is too low for a trustworthy phase reading.

### 1.0.1 — 2026-09-17

-bug fixes
- new warnings
- better phase results and recommendations

### 1.0 — 2026-09-13

No release notes.

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## Related topics

[sdc.com](https://appshunter.io/ios/topics/sdc-com)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-23.*