0x8310 · equalizer

Per-band audio equalizer and microphone noise reduction for HID++ headsets. getEqInfo (function 0) returns the table dimensions: band_count, the gain range in dB, and an EqCapabilities flag indicating whether values are stored as gains or as DSP coefficients. getFrequencies (function 1) pages through the fixed centre frequency (Hz) of every band, up to seven per response. getFrequencyGains / setFrequencyGains (functions 2–3) read and write the signed per-band gains (dB), with setFrequencyGains accepting a GainPersistence selector that controls whether the new values land in RAM only, EEPROM only, or both simultaneously. A separate pair of functions (4–5) reads and writes hardware microphone noise reduction as a single boolean.

• EqInfo — band_count (up to 15 bands), db_range / db_min / db_max (gain limits in dB; effective_range() resolves the "both-zero implies ±db_range" shorthand), capabilities.
• GainLocation — Eeprom (the persistent custom EQ) or Ram (the currently active EQ).
• GainPersistence — Volatile (RAM only), VolatileAndNonVolatile (RAM + EEPROM), or NonVolatileOnly (EEPROM only).

Spec: Logitech HID++ 2.0 — x8310 equalizer. Used by: Typed wrapper in openlogi-hidpp.

Function reference

The EqualizerFeature wrapper (0x8310) exposes:

Methods

All methods are async and return Result<…, Hidpp20Error>.

Types

EqInfo

EQ table information returned by get_eq_info.

Method: effective_range(&self) -> (i8, i8) — resolves the "both-zero implies ±db_range" shorthand into concrete (min, max) bounds.

EqCapabilities

Bitflags indicating how a device stores its EQ values, from get_eq_info.

GainLocation

Selects which copy of the EQ gains get_frequency_gains reads from.

GainPersistence

Controls how set_frequency_gains persists the new gains.

Wire format

Simple getters carry a 3-byte request payload (all zeroes except where noted); set_frequency_gains uses a 16-byte long request. All responses are read from the 16-byte extended payload.

get_eq_info (fn 0)

Request: [0x00, 0x00, 0x00]

Response (byte → field):

get_frequencies (fn 1)

Paged: the wrapper issues one request per page of up to 7 bands until all band_count frequencies are collected.

Request: [start_index, 0x00, 0x00]

Response (byte → field):

get_frequency_gains (fn 2)

Request: [location, 0x00, 0x00]

Response (byte → field):

set_frequency_gains (fn 3)

Uses call_long, a 16-byte request payload.

Request: [persistence, gain[0], gain[1], …, gain[14]]

Response (byte → field):

get_mic_noise_reduction (fn 4)

Request: [0x00, 0x00, 0x00]

Response (byte → field):

set_mic_noise_reduction (fn 5)

Request: [enabled, 0x00, 0x00]

Response is ignored.

Usage (Rust)

use hidpp::{device::Device, feature::equalizer::{EqualizerFeature, GainLocation, GainPersistence}};

// device: &mut Device, already created via Device::new(channel, index)
device.enumerate_features().await?;
if let Some(feat) = device.get_feature::<EqualizerFeature>() {
    // Query EQ table dimensions.
    let info = feat.get_eq_info().await?;
    let (min_db, max_db) = info.effective_range();

    // Read centre frequencies of all bands.
    let freqs = feat.get_frequencies(info.band_count).await?;

    // Read the currently active gains from RAM.
    let gains = feat.get_frequency_gains(GainLocation::Ram, info.band_count).await?;

    // Apply a flat EQ to RAM (volatile, no EEPROM write).
    let flat: Vec<i8> = vec![0i8; usize::from(info.band_count)];
    let echoed = feat.set_frequency_gains(GainPersistence::Volatile, &flat).await?;

    // Toggle microphone noise reduction.
    let nr_on = feat.get_mic_noise_reduction().await?;
    feat.set_mic_noise_reduction(!nr_on).await?;
}