> 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.md).

# Pro4/AA

Old deflated pads create a VERY unreliable graph

<figure><img src="https://31762434-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M4NrSugToAwYkW0a8hV%2Fuploads%2FO1jmGuoqJaYz5poqFyx4%2FKoss%20Pro4AA%20-%20Bad%20seal%20-%20old%20pads.jpg?alt=media&amp;token=2c816dc6-c77d-48bc-a0c5-65c19d22c88e" alt=""><figcaption></figcaption></figure>