> For the complete documentation index, see [llms.txt](https://qudelix.gitbook.io/home/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://qudelix.gitbook.io/home/5k/volume-control/2-way-associative-abs-volume.md).

# 2-way Associative ABS Volume

Qudelix's unique 2-way Associative Absolute Volume ensures optimal audio quality at all volume levels.

* **Smartphone, PC/Laptop volume control**
  * 2dB Step
* **5K Device Volume Control (5K Red Buttons)**
  * 0.5dB Step

{% hint style="info" %}
Whether you adjust the volume on the source device or the 5K, optimal audio quality is consistently maintained. Users can adjust the volume from whichever device is most convenient.
{% endhint %}

***

**How to Verify ABS Volume Functionality**

When you adjust the volume on a smartphone or PC, the smartphone or PC sends a volume command to the 5K. The 5K is programmed to blink its Blue LED whenever it receives these volume adjustment commands from the source device. If the Blue LED blinks when you adjust the source volume, it indicates that the ABS Volume functions correctly.

{% hint style="success" %}
**Music and Call Volume Levels**

The volume levels for music playback (A2DP) and phone calls (HFP) are managed independently.

The volume level adjusted during music playback is saved and applied to A2DP, while the volume level adjusted during a phone call is saved and applied separately to HFP.

Therefore, even if the music volume is set high, the call volume may still be set to a much lower level.

To adjust the call volume, make or receive a phone call and increase the volume while the call is active. The adjusted call volume will then be saved and used for future calls.
{% endhint %}