Audio manufacturers
- Ortofon
- Oscar Adler & Co.
- Oscar Schmidt
- Otamatone
- Output
- Ovation
- OXI Instruments
- Pace
- Pageflip
- Palmer
- Panasonic
- panda audio
- PAS
- Paulus & Schuler GbR
- pBone music
- Pearl
- Pearl Flutes
- Peavey
- Peluso
- Pensa
- Peter Oberrauch
- PG Music
- Phase
- Phil Jones
- Philipp Hammig
- Pickboy
- Pigtronix
- Pinguin
- Pittsburgh Modular
- Playtime Engineering
- Playtronica
- Playwood
- Plug And Mix
- Plugin Alliance
- PMC
- Poly Effects
- Polyend
- Polyverse Music
- Positive Grid
- Powell Sonare
- PPG
- Presonus
- Prism Sound
- Pro-Ject
- Proco
- Prodipe
- Proel
- Providence
- PRS
- PSI Audio
- PSP Audioware
- Pulsar Audio
- Punchlight
- punQtum
- PUR
- PWM
- QSC
- Quested
- Quilter
- Radial Engineering
- Rainer W. Leonhardt
- Ramirez
- Rampone & Cazzani
- Rane
- RCF
- RCS
- Real McCoy Custom
- Reason Studios
- Recording King
- Red Panda
- Reloop
- Remo
- Reverend
- Revv
- RF Venue
- Rhodes
- Richter
- Richwood
- Rickenbacker
- Rides In The Storm
- Riedel
- Rigoutat
- Risa
- Rivera
- RME
- Roadworx
- Rob Papen
- Robaux
- Robotic Bean
- Rockboard
- Rocktron
- Rode
- Rodec
- Rodenberg
- Roger Linn Design
- Roger Schult
- Rogers
- Rohema
- Roland
- Rolls