> 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/akg/akg-k551.md).

# K551

Foam insert is just a circle of urethane over the driver to attenuate some treble

<figure><img src="https://31762434-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M4NrSugToAwYkW0a8hV%2Fuploads%2FapjPteouSurZBKVh3lLf%2FAKG%20K551.jpg?alt=media&amp;token=124819b8-86e0-4130-b220-3f3a06e2d08d" alt=""><figcaption></figcaption></figure>

![](https://31762434-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M4NrSugToAwYkW0a8hV%2F-MeZrfX_ES8HbNcZ098F%2F-MeZvaT3iPFsofFm-Uyb%2F_DSC5851.jpg?alt=media\&token=b0edd3ce-4924-409a-879b-f8dcfa7358a4)