Audio Quality
Noctune’s transcription accuracy depends on the audio it receives. This page covers what makes a clean recording and how to avoid the most common problems. The underlying transcription engine (Deepgram) accepts a very wide range of inputs, but a few habits make a noticeable difference.
Quick checklist
- Mic close, mouth forward. 6–12 inches from your mouth is a good target.
- Record in a quiet space. HVAC, dishwashers, and hallway chatter degrade accuracy more than you’d expect.
- One speaker at a time when possible. Simultaneous speech is the #1 cause of garbled transcripts.
- Keep levels consistent. Avoid shouting then whispering — the AI normalizes, but extremes introduce errors.
Sample rate
Noctune handles any sample rate Deepgram does — commonly 8000, 16000, 24000, 32000, or 48000 Hz. In practice you don’t need to think about this; recording at your device’s native rate is correct. Don’t upsample telephony audio (8 kHz) to 16 kHz — it introduces artifacts that hurt accuracy.
| Source | Native rate | Good for Noctune? |
|---|---|---|
| iPhone / Android voice memo | 44.1–48 kHz | Yes |
Browser getUserMedia | 48 kHz | Yes |
| Bluetooth headset (HFP) | 8–16 kHz | Yes, but avoid when possible |
| Desk phone handset | 8 kHz | Yes — don’t resample |
Format and codec
Any of these work:
- MP3, M4A (AAC), AAC — what most phone voice memos produce
- WAV (PCM / Linear16), FLAC — higher bandwidth, no compression artifacts
- Ogg, Opus, WebM — common for browser recording
If you have a choice, favor FLAC or WAV (lossless) for archival clarity and M4A/MP3 for smaller files. AAC and MP3 at reasonable bitrates (96 kbps+) are indistinguishable from lossless for transcription purposes.
Channels
Mono is fine and what most voice recorders produce. Stereo offers no accuracy benefit unless each speaker is on a separate channel, which is rare for in-room recordings.
Reducing noise
Things that noticeably help:
- Clip-on lavalier or headset mic over built-in laptop/phone mics — closer to mouth, less room.
- Carpet, curtains, soft furniture dampen reverb; tiled exam rooms are the worst case.
- Turn off ceiling fans, radios, and diagnostic equipment during the appointment when feasible.
- Don’t cover the mic. Pockets muffle the mid-range frequencies speech relies on.
Length
There is no lower bound on length. Upper bound is covered in Supported Formats & Limits.
Common symptoms and fixes
| Symptom | Likely cause | Fix |
|---|---|---|
| Words dropped or merged | Mic too far / mouth turned away | Move mic closer; face the mic |
| Repeated words (“the the”) | Echo / reverb | Record in softer room |
| Owner’s speech missing | One-sided mic placement | Place mic between you and the owner |
| Drug names wrong | Fast speech / background noise | Speak drug names slightly slower; add to templates |
| Breed names wrong | Uncommon breed + noise | Spell out once at start of visit |
Sources: Deepgram Supported Audio Formats , Determining Your Audio Format .