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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.

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.

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.

  1. Describe your system

    Front stage, rear channels, subwoofer topology, DSP channel mapping, and speaker distances.

  2. Measure with REW

    Enable REW's API, load your mic calibration, and capture your system's response.

  3. Generate the tune

    Crossovers, EQ to your target curve, level matching, and time alignment — calculated for you.

  4. Push to your DSP

    Load the generated EQ straight into your Helix DSP.

  5. 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.

System setup screen with front-stage topology, rear channels, subwoofer, and DSP selection
Describe your system — front-stage topology, rear channels, subwoofer, and your DSP.
REW connection field and desired crossover points for each driver
Set the REW connection and crossover points for each driver.
Target curve review screen showing the target response graph
Review the target curve your EQ will aim for.
Per-channel RTA measurement capture from REW
Capture each channel from REW with a moving-mic RTA measurement.
EQ generation screen with measured, target, and predicted-after-EQ curves
Generate EQ to the target and copy filters straight to the DSP.
Level matching screen balancing output across channels
Match levels across every channel.
Time alignment screen with per-driver distances and computed delays
Enter each speaker's distance — per-channel delays are calculated for you.
Final tuning report showing initial measurements and applied EQ filters
Finish with a full tuning report of measurements and applied EQ.

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's a complete example — scroll through all pages below.

Open the full report (PDF)

Before you start

What you'll need.

Pricing

Choose your license.

One-time

Perpetual license

$39.99 one-time · single seat
  • Full guided tuning workflow
  • Single-seat license
  • One-time purchase, yours to keep
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Most complete

Pro subscription

$299.99 per year
  • Everything in the perpetual license
  • All updates while subscribed
  • Priority support
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Get the app

Download Flat Liner Tuning

Grab the installer for your platform and start tuning. Questions first? Reach out any time.

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