Help

Setup, troubleshooting, and how the numbers work.

One engine, two apps. Everything below is shared unless a Mac or iPhone tag says otherwise.

Getting started

Mac

Connect your gear

  1. Open Input / Output in Settings (⌘,).
  2. Choose your mic — a calibrated USB mic (UMIK-1, UMM-6, and similar) for true SPL, or the Mac's built-in mic, which works too.
  3. Choose your output — any wired device. AirPlay and Bluetooth are blocked for the sweep itself; see Troubleshooting.
  4. Prefer not to think about any of this? Sweep can walk you through it instead — see Simple mode below.
iPhone

Just open the app

  1. No setup needed — the built-in mic and speaker work immediately.
  2. For true SPL, plug in a calibrated mic like the iMM-6C via a Lightning or USB-C adapter.
  3. Hold the phone at your listening position for the measurement.

Set your levels first

Set Levels plays steady pink noise while a live meter listens. Bring the volume up to a good target before you measure — loud enough to read well, not so loud it distorts.

Then measure

Press Measure (Mac) or the record button (iPhone). Your speakers play a smooth rising tone — every note they can make, lowest to highest — and Sweep does the math right there on your device.

Simple mode

Mac

You don't have to learn the analyzer to use Sweep. On first launch, the Mac app asks whether you have a receiver with tone knobs or you'd rather work in the full analyzer — pick the receiver path and Sweep opens in a guided shell instead of the instrument window described above.

A wizard measures for you

Tune My Receiver walks through Set Levels and the sweep step by step, then recommends actual knob positions for your receiver — turn Bass to 3, Treble to −1 — instead of an abstract EQ curve you'd have to translate yourself.

A plain-language results tour

After measuring, a short guided tour walks through what Sweep found in your room, in the same non-technical language as this page — not a chart you're left to interpret alone.

Balance Speakers

A quick guided check that your left and right channels are actually matched in level before you start tuning.

Switch anytime

The Simple / Advanced switcher sits in the same spot in both shells, and both work from the same measurement library — nothing you capture is shell-specific. Changed receivers, or want the full analyzer now? Settings → Measurement → Change my setup… resets the first-launch choice.

How Sweep measures

A sweep plays

Your speakers play a smooth rising tone from 20 Hz to 20 kHz — the same technique the professional bench tools use.

The math happens on your device

Sweep compares what it played with what it heard, keeps the sound that came straight from the speakers, and sets aside the room's late echoes. The chart is the result — no cloud, no accounts.

Sweep trusts each mic only as far as it can hear

A calibrated mic is trusted across the whole range. An uncalibrated USB mic or interface is trusted full range too, just without true SPL. Built-in and Bluetooth mics have real limits — Sweep stops the line rather than showing you the microphone's fiction. See Which mic should I use? below.

Reading the chart

Shape is the story

The curve shows which notes come out strong and which fall behind — that shape is what knobs and EQ tune. With a calibrated mic, the SPL axis mode also shows true loudness.

The low end is your room

Bass lingers and bounces, so down low every measurement is speaker plus room. Narrow bumps and dips there belong to walls and corners — moving your speakers or your seat changes them; knobs mostly can't.

Lines stop where knowledge stops

Every trace ends at the deepest point its capture can honestly claim — the measurement gate's limit or the microphone's, whichever comes first. No line is drawn where there's no knowledge behind it.

Which mic should I use?

A calibrated USB mic is the gold standard — Sweep corrects for the mic itself and reads true SPL. No mic to hand? The built-in mic genuinely works for tuning, just with a real low-end limit. Sweep detects which one you're using and sets the trust range automatically; this isn't something you configure.

InputTrusted from
Calibrated USB mic20 Hz, true SPL
Uncalibrated USB mic / interface20 Hz, relative level
Built-in mic (Mac or iPhone)~90 Hz
Bluetooth mic~100 Hz – 8 kHz only
Unrecognized input~60 Hz

Troubleshooting

Sweep says it needs microphone access

Measurements listen through your mic. Allow Sweep in System Settings → Privacy & Security → Microphone (Mac) or Settings → Sweep (iPhone), then come back.

"Your mic and speakers disagree on speed"

Mac

Your input and output devices are running at different sample rates. Sweep can usually set them to match automatically — if that fails, Audio MIDI Setup can set both devices to the same rate by hand.

"Your selected device isn't connected"

Plug it back in, or pick a different input or output from the device menu.

Bluetooth headphones took over the audio

Their hands-free microphone runs at call quality — too low to measure with, and it can interrupt playback mid-sweep. Choose a wired output and your USB mic, or disconnect the headphones.

It won't let me measure over AirPlay or Bluetooth output

That's deliberate. Wireless output adds delay a sweep can't see through, which corrupts the timing math with no visible symptom — Sweep would rather stop than hand you a result that looks valid and isn't. Pink noise for level-setting is unaffected; only the sweep itself is blocked.

"Sweep didn't hear anything" / the capture looks empty

Check that the right input is selected and your mic is unmuted, that the right output is selected and the volume is up, then run the sweep again.

The measurement looks distorted or clipped

That sweep was a little too loud for the mic. Turn the volume down a touch — using Set Levels first will usually catch this before it happens — and measure again.

Audio keeps getting interrupted

Something is repeatedly disrupting the audio system — often another app claiming the same device, or a Bluetooth device reconnecting mid-session. Check your input and output choices, close anything else using audio, and try again.

Can I import my REW measurements?

Mac

Yes — REW .txt exports import directly into your library. EQ designs export to REW and miniDSP filter formats, and impulse responses export as WAV.

Privacy

No account, no ads, no network needed.

Sweep is an app, not a service: your measurements are ordinary files on your device, and everything it does — the sweep, the math, the charts — happens right there. That's the whole policy.

This section, together with the full privacy section on the main site, serves as the privacy policy for the Sweep apps on Mac and iPhone.

Still stuck?

Reach out through the contact info on my site and I'll get back to you.

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Sweep Sweep

Speaker measurement for Mac and iPhone. Gated relative response — the low end reflects your room, and the chart says so.

Sweep
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