> For the complete documentation index, see [llms.txt](https://docs.anthriq.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.anthriq.com/bxi-studio/configure/gain-frequency.md).

# Set gain and frequency (Instinct and xSys)

<figure><img src="https://2761951758-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhtBZnSGOC4EMhU3nc5oM%2Fuploads%2FFYMv1lqdh8C5Hbj1FJHv%2Finstinct_gain.png?alt=media&amp;token=8b9a84ed-47ae-412d-a8dc-c178ff904ec3" alt=""><figcaption></figcaption></figure>

This page configures the analog front-end parameters that determine how the device acquires biosignals. Default values are pre-set for general-purpose use. Adjust them here or later during a streaming session.

## Configuration rows

### Synap: signal amplification

The primary signal channel gain, computed as two stages multiplied together.

* **Gain 1**: first-stage amplification (1×, 2×, 4×, 6×, 8×, 12×, 20×, 24×).
* **Gain 2**: second-stage amplification (same options).
* **Total**: auto-computed product (purple badge, read-only).

Example: Gain 1 = 20, Gain 2 = 100, Total = 2000× amplification.

### REF: reference channel

Same dual-gain structure as Synap, applied to the reference electrode.

### LPF: low-pass filter

Controls the anti-aliasing filter cutoff frequency.

* **Synap**: filter frequency for signal channels.
* **REF**: filter frequency for the reference channel.
* Options: 100 Hz, 262 Hz, 524 Hz, 1048 Hz, 2096 Hz, 4192 Hz.

Higher values pass more high-frequency content. For standard EEG, 262 Hz is typical.

### CMS: common mode sense

Gain settings for the common-mode rejection circuit.

* **Gain 1** and **Gain 2**: adjust to optimize noise rejection.

### DRL: driven right leg

The active noise cancellation circuit.

* **Gain**: DRL amplification factor.
* **Impedance Measurement**: toggle switch to enable electrode impedance checking.

When impedance measurement is enabled, the device periodically checks electrode contact quality during streaming.

## Use the dropdowns

* Click any value field to open a dropdown.
* The currently selected value highlights in orange.
* Select a new value: the dropdown closes and the value updates.
* For Synap/REF rows, the Total recalculates automatically.

## Default values

| Row   | Default                    |
| ----- | -------------------------- |
| Synap | 20 × 100 = 2000            |
| REF   | 20 × 100 = 2000            |
| LPF   | Synap: 100 Hz, REF: 100 Hz |
| CMS   | 1 × 100                    |
| DRL   | 100, Impedance: ON         |

These defaults work well for general-purpose EEG acquisition at standard sampling rates.

> **Tip:** These values can also be adjusted later from the streaming configuration panel during a live session.