Works with REW
Talks directly to Room EQ Wizard's local API to capture measurements and apply changes. Supports Helix copy and paste EQ filters into DSP.
The app
Tune your car audio like a pro.
Flat Liner Tuning is a desktop app that walks you through dialing in an active car-audio DSP system. It connects to Room EQ Wizard (REW), measures your system, and generates precise crossover, EQ, level, and time-alignment settings, one guided step at a time.
What it does
Everything you need to tune, in one place.
Guided walkthrough
Asks one thing at a time, confirms every major decision, and never assumes your system layout. Built for active systems, not guesswork.
Crossover setup
High-pass, low-pass, and band-pass for two-way, three-way, rear fill, and subwoofer topologies, set to your chosen crossover points.
EQ to a target curve
Runs an RTA measurement, applies your target curve, and generates the EQ filters to match it.
Level matching
Normalizes front left/right, balances rear against front, and matches subwoofer level to the front stage.
Time alignment
Calculates per-channel delay from the physical distance of each speaker to your listening position.
Verification sweep
Runs a post-tuning sweep and compares it against your target curve, then suggests adjustments where they're needed.
Runs on your machine
A self-contained desktop app for Windows and macOS. Installs everything it needs, and keeps your data local. Nothing in the cloud.
How it works
From setup to verified tune.
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Describe your system
Front stage, rear channels, subwoofer topology, DSP channel mapping, and speaker distances.
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Measure with REW
Enable REW's API, load your mic calibration, and capture your system's response.
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Generate the tune
Crossovers, EQ to your target curve, level matching, and time alignment, calculated for you.
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Push to your DSP
Load the generated EQ straight into your Helix DSP.
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Verify
Run a final sweep against the target curve and fine-tune until it's right.
See it in action
A look inside the app.
Sample output
See a full tuning report.
Every tune finishes with a detailed report of your initial measurements, target curve, applied EQ, levels, and time alignment. Here is a complete example. Scroll through all pages below.
Before you start
What you'll need.
- A Windows PC or a Mac. See the minimum system requirements below.
- Room EQ Wizard (REW) installed on the same machine, with its API enabled (REW → Preferences → API).
- A measurement microphone and its calibration file (if available).
- A DSP (Helix DSP supported for EQ loading, more being added).
System requirements
Minimum system requirements.
Flat Liner Tuning runs alongside REW, and REW does the heavy lifting: real-time sweeps, FFT analysis, and live graphing. These minimums are set deliberately above the bare floor so measurements stay reliable on the machine you actually take to the car.
Windows
- Operating system
- Windows 10 64-bit (version 21H2 or newer) or Windows 11. 32-bit Windows is not supported.
- Processor
- Quad-core Intel Core i5 (8th gen) or AMD Ryzen 5 / equivalent, 2.0 GHz or faster.
- Memory
- 8 GB RAM minimum · 16 GB recommended (REW is memory-hungry with long sweeps).
- Storage
- 2 GB free for the app, REW, and saved measurements. An SSD is strongly recommended.
- Display
- 1600 × 900 or larger · 1920 × 1080 recommended so the response graphs stay readable.
macOS
- Operating system
- macOS 12 Monterey or newer.
- Processor
- Apple silicon (M1 or newer), or a quad-core Intel Core i5 from 2018 or later.
- Memory
- 8 GB unified memory / RAM minimum · 16 GB recommended.
- Storage
- 2 GB free for the app, REW, and saved measurements.
- Display
- 1440 × 900 or larger · 1920 × 1080 recommended.
Required on all platforms
- Room EQ Wizard (a current release), with the API enabled. REW needs a Java runtime. The standard REW installer includes one.
- A free USB port for your measurement microphone or audio interface, plus any adapter your machine needs.
- An internet connection for license activation and update checks. Tuning itself works offline.
- Mains power during a tune. Keep the laptop plugged in and prevent it from sleeping. Power saving can throttle the CPU mid-sweep and skew a measurement.
Below these specs the app will usually still launch, but sweeps take longer, graphs redraw slowly, and REW can run out of memory on long measurement sessions. Netbooks, Atom/Celeron-class laptops, 4 GB machines, and mechanical hard drives are not recommended.
Pricing
Choose your license.
Get the app
Download Flat Liner Tuning
Grab the installer for your platform and start tuning. Questions first? Reach out any time.