# Razer Support Ticket - THX EQ and Spatial Audio Not Working
**Subject:** THX Spatial Audio EQ and effects have no impact on audio output - root cause identified
---
**Device:** Razer BlackShark V2 Pro Rainbow Six Edition (USB VID_1532, PID_0528)
**Software:** Razer Synapse 4.0.660
**OS:** Windows 11
**Driver:** oem71.inf (THX_Spatial_Audio_for_Digital_Peripherals v3.2.3.0)
---
## Problem Description
THX Spatial Audio EQ, bass boost, normalization, vocal clarity, and spatial processing have **zero effect on audio output**. All sliders and toggles in Synapse 4 are visually interactive but produce no audible change whatsoever.
This was **previously working** and stopped working at some point — likely after a Synapse 4 or Windows update.
---
## Diagnostic Steps Performed
Extensive technical diagnosis was performed. Here are the findings:
### 1. THX APO is correctly installed and loaded
- `THXOutAPO-SSE2-v3.dll` (v3.2.3.0) is loaded in `audiodg.exe` — confirmed via PowerShell module inspection
- `THXMicAPO-SSE2-v3.dll` (v3.2.3.0) is loaded in `audiodg.exe`
- THX APO is correctly registered in the Windows audio device registry (`FxProperties`) for the active render device
### 2. Active render device confirmed
- Active MMDevice GUID: `{f161352a-6f6f-439d-9e8f-62dd58e8d5af}` (DeviceState = 1)
- FxProperties entry: `{b725f130-47ef-101a-a5f1-02608c9eebac},10 = "THX Spatial Audio (BlackShark V2 Pro)"` ✅
- THXAPOCOMPONENT correctly referenced in FxProperties ✅
- Audio Enhancements enabled in Windows sound settings ✅
- Spatial Sound set to OFF (no conflict with Windows Sonic) ✅
### 3. Synapse successfully communicates with THX control DLL
From `ThxV3Native.log`, all commands return `r: true`:
```
SetRenderEQGains containerId: {DE739735-...} renderEQData: [12,12,12,12,12,12,12,12,12,12] r: true
SetRenderSpatialProcessing containerId: {DE739735-...} enabled: 1 r: true
SetRenderBassBoost containerId: {DE739735-...} enabled: 1 r: true
SetRenderBatch containerId: {DE739735-...} enabled: 0 r: true
```
### 4. Audio signal is NOT modified — confirmed by objective measurement
A Python test was written to play white noise through the device and capture the output via WASAPI loopback, measuring the FFT spectrum before and after EQ changes. **The spectrum showed zero change** across all frequency bands despite EQ being set to +12dB on all bands, confirming the APO is running in bypass mode.
Additionally, continuous white noise was played while switching EQ settings in Synapse — **no audible difference was perceived**.
### 5. Root cause identified — JSON preset files are NOT updated by Synapse
THX APO reads EQ settings from JSON files located at:
```
C:\ProgramData\THX\usb\1532\0528\thx-headphones-stereo-*.json
```
Each preset file contains an `eqCurve` array of 31 values. These files are **never updated** by Synapse when EQ sliders are changed. The `eqCurve` remains all zeros regardless of Synapse settings.
**Proof:** Manually editing the JSON file (setting all `eqCurve` values to 12.0) and restarting Synapse produced a noticeable change in audio — confirming APO reads from these files.
**Conclusion:** Synapse sends EQ commands to `ThxV3Native_v1.0.41.1.dll` which returns `r: true`, but the changes are **never persisted to the JSON files** that `THXOutAPO-SSE2-v3.dll` actually uses for processing.
### 6. Component versions
- `THXOutAPO-SSE2-v3.dll` in System32: **v3.2.3.0**
- `ThxV3Native_v1.0.41.1.dll` (Synapse control layer): **v1.0.41.1**
- Config path referenced in registry: `C:\ProgramData\THX\usb\1532\0528\thx_spatial.conf.json`
---
## Expected Behavior
When EQ sliders or THX settings are changed in Synapse 4, the audio output should change accordingly. This worked previously.
## Actual Behavior
All THX audio processing is stuck at default/flat settings. No slider or toggle in Synapse 4 has any effect on the actual audio output.
---
## Request
Please investigate the broken write path between `ThxV3Native` and the THX APO JSON configuration files. The issue is specifically that Synapse does not update `eqCurve` and other parameters in the preset JSON files when settings are changed, causing THX APO to always apply flat/default processing.
A firmware or Synapse update that restores this functionality would resolve the issue.