Potok transcribes Russian speech; this site has been translated into English for convenience.
HFP and A2DP are two modes of a Bluetooth headset. HFP carries voice from the microphone to the device, but with a low quality of the link; A2DP carries only music in the best quality, but with no microphone at all. When the headset is switched to the mode with a microphone (HFP), the sound quality for the other party usually drops; that is the limit of the profile itself.
An ordinary Bluetooth headset actually has two different sound modes, and they are not interchangeable: one is made for music, the other for talking with a microphone.
How the Bluetooth audio profile HFP differs from A2DP
HFP (Hands-Free Profile) and A2DP (Advanced Audio Distribution Profile) are Bluetooth profiles that describe how a headset carries sound. HFP carries voice from the microphone with low quality: the link is technically built as a monophonic SCO channel with CVSD or PCM modulation and logarithmic quantization. A2DP, on the contrary, carries only music without a microphone: this profile carries an audio stream of up to two channels (stereo) in one direction, to the headset or from it, but not a voice channel.
Hence the difference in quality: A2DP carries stereo sound in much higher quality than HFP. A similar logic of built-in limits exists in macOS Dictation: the system function connects to any text field, but needs a separate start and does not work by itself.
| Term | Meaning | Example |
|---|---|---|
| Bluetooth audio profile HFP/A2DP | Bluetooth headset modes: HFP carries voice from the microphone with low quality, A2DP only music without a microphone | when the headset is switched to the mode with a microphone (HFP), the sound quality for the other party usually drops |
| Microphone privacy | OS settings that control which apps have access to the device microphone | in Windows and macOS, the list of apps with access to the microphone can be viewed and changed in the privacy settings |
| Group policy for speech services | a corporate Windows setting that can restrict or turn off voice services on work computers | the message “voice services are managed by your organization” means that the function was turned off by a group policy |
| Audio device driver | a software component through which the operating system interacts with a specific microphone or sound card | an outdated audio device driver sometimes causes the microphone not to be detected |
An example from dictation
When the headset is switched to the mode with a microphone (HFP), the sound quality for the other party usually drops. This is noticeable in calls: as soon as the headset turns on the microphone, music or the other party's voice in the headphones starts to sound duller than in A2DP mode. This is not a breakdown of a particular headset but the limit of the HFP profile itself.
For any program that needs voice from a headset, from system Win+H voice input to a third-party app, this means the same thing: only HFP has a voice channel, so the drop in sound quality for the time of recording is not a fault of a particular program but the limit of the profile itself.
How this affects Potok, and where it does not
Potok is an ordinary program from the microphone's point of view: for dictation it needs system access to the microphone, without it dictation does not work, and the microphone itself is chosen in the Potok settings and in the menu of its tray icon. Since A2DP carries only music without a microphone, the headset in this mode has no voice channel, and no program can take voice from it, Potok included: you need HFP mode, where there is a microphone channel.
Besides the choice of microphone, Potok is a cloud service: recognition runs on servers in Russia, and it does not work without the internet.
One Potok subscription is the dictation app and the Telegram bot @potok_now_bot for recordings and voice messages.
Frequently asked questions
Since A2DP carries only music without a microphone, the headset in this mode has no microphone channel, and no program can take voice from it. The microphone appears when the headset is switched to HFP mode.
Check it in one evening
Install Potok, dictate what you usually type and compare. 14 days of full access, no card needed. Potok is a cloud service: speech is recognized on servers in Russia, and it does not work without the internet.
Download PotokThe Potok subscription also includes the Telegram bot @potok_now_bot: forward it a voice message or a long meeting recording and it returns the text. Without a subscription the bot gives 60 minutes per month for free.
Built-in dictation and Potok
| Tool | Where it works | Russian language | Where speech is recognized |
|---|---|---|---|
| Windows voice typing (Win+H) | Windows 10 and 11 | Windows 11 only | Microsoft cloud, does not work offline |
| macOS Dictation | macOS | yes | on the device or on Apple servers |
| Potok | Windows, macOS, Linux | primary language | cloud, servers in Russia, does not work offline |
Primary sources: en.wikipedia.org · support.microsoft.com