HFD Export (Hypex FA Series)

Overview

LinFIR can generate Config.xml project files for Hypex FA series amplifiers:

• FA251, FA501 (1-channel with DSP)
• FA122, FA252, FA502 (2-channel with DSP)
• FA123, FA253, FA503 (3-channel with DSP)

About Config.xml: This is the native project file format used by the Hypex Filter Design (HFD) software. HFD opens and uploads Config.xml files directly to FA series amplifiers. LinFIR generates a ready-to-use Config.xml that you can open in HFD immediately.

This integration enables direct deployment of your loudspeaker designs to Hypex amplifiers without manual coefficient transfer.

Availability: HFD export is available in Loudspeaker Design mode — no license required. It is not available in Room Calibration mode. The Hypex FusionAmp mode (license required) is a separate, optional project mode that also supports HFD export, with added hardware-matched guardrails (locked sample rate, tap limits, biquad limits).

✅ Driver Adjustments Included: Unlike standard FIR/IIR exports, HFD export automatically includes gain, time delay, and polarity settings for each driver. These are written directly into the Config.xml file and applied by the amplifier.

Supported Device Models

Requirements

Sample Rate: HFD export requires 93.75 kHz sample rate

• FA series amplifiers operate at 93.75 kHz internally
• If your LinFIR project uses a different sample rate, you must change it before HFD export
• Set Sampling Frequency to 93.75 kHz in Target DSP Settings

Biquad Limit: Maximum 15 biquads per channel

• LinFIR automatically counts biquads when exporting
• Global IIR filters + driver IIR filters must not exceed 15 biquads per output channel
• See Biquad Count Reference for calculation details

FIR Position: Choose between two FIR filter placement options:

1. Input FIR (Global, 4500 taps maximum):

   • Single FIR filter applied to the input signal before channel routing
   • Suitable for global room correction or full-range equalization
   • More efficient for shared corrections across all channels

2. Output FIR (Per-channel, 1500 taps maximum per channel):

   • Independent FIR filters for each output channel
   • Suitable for per-driver crossover and correction filters

Export Workflow

1. Configure HFD Settings

Open Menu > Export HFD to access the HFD export window:

• Mode: Choose between Create from template or Patch existing Config.xml (see Patch Mode)
• Device Model: Select your Hypex FA amplifier model
• FIR Position: Choose Input (global) or Output (per-channel) FIR placement
• Channel-to-Driver Mapping: Assign the filters of each LinFIR driver to a FusionAmp output channel

2. Map Drivers to FusionAmp Channels

The mapping table assigns the FIR filters, IIR filters, gain, delay, and polarity computed for each LinFIR driver to a specific FusionAmp output channel. Channels are numbered as they appear in the HFD Config.xml.

By default, LinFIR assigns drivers sequentially: the first driver goes to Channel 1, the second to Channel 2, and so on. If there are fewer drivers than channels, the last driver is repeated for the remaining channels.

Mapping Validation:

• LinFIR checks that all mappings are valid before export
• Warnings appear if biquad count exceeds 15 for any channel
• FIR length validation ensures compliance with Input (4500) or Output (1500) tap limits

3. Select Presets to Export

Hypex FA amplifiers support multiple configuration presets (typically 3). Choose which presets to include in the exported HFD file:

• ☑ Preset 1: Main tuning
• ☑ Preset 2: Alternate voicing
• ☐ Preset 3: (Skip)

Uncheck presets you don’t want to modify in the existing configuration.

4. Patch Mode (Update Existing Configuration)

Patch Mode allows you to update an existing Config.xml instead of creating one from scratch. Select Patch existing Config.xml in the Mode dropdown.

1. Select Mode: Set the Mode dropdown to Patch existing Config.xml
2. Browse: Click Browse… and select the Config.xml file on your disk
3. LinFIR will:
   • Auto-detect the FIR position (Input or Output) from the loaded file
   • Parse existing presets and channel configurations
   • Lock FIR position and device model to match the loaded file
4. Update Selected Presets: Only the presets you’ve checked will be modified; others remain unchanged
5. Click Apply mapping and export — the selected Config.xml is overwritten in place

Use Cases for Patch Mode:

• Update filter coefficients after design refinements
• Safely modify one preset without affecting others
• Create different presets (boosted bass, different voicing, etc.)

5. Validation and Export

Before exporting, LinFIR performs comprehensive validation:

Biquad Count Check:

Tweeter has 18 biquads but HFD supports max 15 biquads per channel

Reduce IIR or Auto-EQ filter count for this driver.

FIR Length Check - Position Input:

Global FIR has 6000 taps but Input position supports max 4500 taps

Reduce global FIR length or switch to Output position.

FIR Length Check - Position Output:

Woofer has 2000 taps but Output position supports max 1500 taps per channel

Reduce driver tap count or switch to Input position.

Sample Rate Check:

HFD export requires 93.75 kHz sampling rate. Current: 96000 Hz

Change sample rate to 93.75 kHz in Settings.

If validation passes, click Apply mapping and export:

• In Create from template mode: a Save As dialog opens — choose the location and filename (Config.xml is pre-filled)
• In Patch mode: the selected Config.xml is overwritten in place immediately

A confirmation message is shown below the export button on success.

6. Load Configuration to Amplifier

Use Hypex Filter Design (HFD) (Windows only, the official Hypex software for configuring their DSPs) to upload the exported Config.xml to your FA series amplifier:

1. Connect amplifier via USB

2. Open Hypex Filter Design (HFD)

3. Go to File > Import Project

   

4. In the file dialog, switch the file type dropdown (bottom-right) to All files — otherwise HFD won’t show .xml files

   

5. Select the exported Config.xml file

6. Click Upload to Device

Related Documentation

• Hypex FusionAmp Mode - Project mode with hardware-matched guardrails
• Export & Project Management - Standard FIR/IIR export, available in all project modes