mp3
Universal — RingCentral, Nextiva admin, mobile-app prompts, any web player. Smallest file, plays everywhere.
wav
Uncompressed PCM — Twilio, Amazon Connect, 3CX, Avaya. Set Sample Rate 8 kHz or 16 kHz to match your PBX.
wav_mulaw
G.711 µ-law 8 kHz — native Asterisk, FreePBX, Amazon Connect, Cisco NA. Skip on-call transcoding on the PBX.
wav_alaw
G.711 a-law 8 kHz — native Cisco EU, European ITSPs, most non-NA carriers. Same fidelity, different companding curve.
ogg
Vorbis in an OGG container — Firefox-native playback, open-source apps, embedded devices that reject MP3 patents.
opus
Modern low-bitrate codec — WebRTC, Discord, Signal, any SIP trunk that already negotiates Opus. Best speech quality per kilobyte.
webm_opus
Opus in a WebM container — browser-native (Chrome / Edge / Firefox), ideal for <audio> tags on marketing pages and web IVR clients.
m4a
AAC in an MP4 container — iOS / macOS native, Apple Podcasts, iMessage voice notes, any Apple-side production chain.
flac
Lossless archival — keep a master copy for re-mastering later or handing to a downstream mastering studio. Not for PBX playback (file too big).
All values are real SpeechGen Settings panel options. Open the panel under the editor, set Format / Sample Rate / Channels to match your platform, hit Convert. Your file is phone-system-ready on first Convert.