> For the complete documentation index, see [llms.txt](https://itsgreq.gitbook.io/headphone-measurements/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://itsgreq.gitbook.io/headphone-measurements/koss/pro4-aa/koss-pro4-aa-+-pressure-applied.md).

# Koss Pro4/AA + pressure applied

Artificial pressure applied with elastic to force a strong bass seal between pads and silicone ears

<figure><img src="https://31762434-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M4NrSugToAwYkW0a8hV%2Fuploads%2Fc2fU2wtl6pp2MKkmpObl%2FKoss%20Pro4AA%20-%20Pressure%20added%20for%20bass%20seal%20%2B%20heavy%20smoothing.jpg?alt=media&amp;token=564af9ad-0a02-4cc7-b871-56cfa3b317c4" alt=""><figcaption></figcaption></figure>