| .NAK | Unknown Developer | Ficheiros de Áudio | Older Version Audio File | Unknown Software | Unknown Developer |
| .NAP | McAfee, Inc. | Ficheiros de Áudio | McAfee ePO Network Associates Package | McAfee ePolicy Orchestrator | McAfee, Inc. |
| .NCH | Microsoft Corporation | Ficheiros de Áudio | On Hold Message/Music File | Microsoft Outlook Express | Microsoft Corporation |
| .NIFF | Personal Composer | Ficheiros de Áudio | Notation Interchange File Format | Personal Composer | Personal Composer |
| .NIST | Machine Intelligence Laboratory | Ficheiros de Áudio | HTK NIST Audio Data | Awave Studio | FMJ-Software |
| .NKC | Native Instruments | Ficheiros de Áudio | Kontakt Library Data File | Native Instruments Kontakt | Native Instruments |
| .NKI | Native Instruments | Ficheiros de Áudio | KONTAKT Instrument File | Native Instruments Kontakt | Native Instruments |
| .NKM | Native Instruments | Ficheiros de Áudio | Kontakt Multi Instrument File | Native Instruments Kontakt | Native Instruments |
| .NKS | Native Instruments | Ficheiros de Áudio | Kontakt Monolith Container | Native Instruments Kontakt | Native Instruments |
| .NML | Native Instruments | Ficheiros de Áudio | Traktor Collection File | Traktor | Native Instruments |
| .NOKIA | Nokia | Ficheiros de Áudio | Nokia Proprietary Ringtone | Nokia PC Suite | Nokia |
| .NOTE | Failsafe Games | Ficheiros de Áudio | Notessimo Composition | Notessimo | Starburst |
| .NPL | Nokia | Ficheiros de Áudio | Nokia Playlist File | Nokia Multimedia Player | Nokia |
| .NRA | Nero AG | Ficheiros de Áudio | Nero Audio Compilation | Nero 2017 | Nero AG |
| .NRT | Nokia | Ficheiros de Áudio | Nokia Ringtone | Nokia Suite | Nokia |
| .NSA | Nullsoft | Ficheiros de Áudio | Nullsoft Streaming Audio File | Nullsoft Winamp | Nullsoft |
| .NSF | Unknown Developer | Ficheiros de Áudio | NES Sound Format File | DeliPlayer | Open Source |
| .NSP | PENTAX Medical | Ficheiros de Áudio | Computerized Speech Lab Audio Speech Format | Computerized Speech Lab | PENTAX Medical |
| .NST | Microsoft Corporation | Ficheiros de Áudio | Outlook Connector For Notes File | Microsoft Outlook | Microsoft Corporation |
| .NTN | NOTION Music, Inc. | Ficheiros de Áudio | NOTION Song File | VirtuosoWorks NOTION | NOTION Music, Inc. |
| .NTW | NoteWorthy Software | Ficheiros de Áudio | Noteworthy Composer Song File | NoteWorthy Composer | NoteWorthy Software |
| .NVF | Creative Technology Ltd. | Ficheiros de Áudio | Creative Labs NVF Audio File | Apple iTunes | Apple |
| .NWC | NoteWorthy Software | Ficheiros de Áudio | NoteWorthy Composer File | NoteWorthy Composer | NoteWorthy Software |
| .NWI | Clavia DMI AB | Ficheiros de Áudio | Nord Wave Manager Instrument Sample | Nord Sound Manager | Clavia DMI AB |
| .NXT | NeXT | Ficheiros de Áudio | NeXTSTEP Sound Format | NeXTSTEP | NeXT |
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