BroadTalk

Specifications

Every parameter in one place.

What engineers can set, with defaults and ranges – and what we measured. Settings change live in the admin; where a new connection is needed, we say so.

Audio and codec

What travels over the network, and how the server handles it.

ParameterDefaultRange, note
Codec Opus for speech and music alike
Internal format 48 kHz · mono · float32 —
Frame size 20 ms (960 samples) on the mixer’s own high-resolution clock
Opus bitrate (down)The mix the server sends each client. 64 kbps 6–510 kbps · applies to new connections
Upload bitrate (up)What the browser sends: microphone or feed input. 64 kbps 6–510 kbps · applies to new connections
Error correction Opus FEC + PLC a single lost packet restored inaudibly
Opus complexity 5 0–10 (server setting)
Output limiter per listener instant attack, gradual release

Latency

Measured with the synthetic test client: sender encode → RTP → jitter buffer → mixer → encode → RTP → receiver decode.

ParameterDefaultRange, note
Server path, adaptive bufferDefault settings. 31.6 ms median
Server path, fixed 1 frame 18.3 ms median; min 18.3, max 19.1 ms
Server path, fixed 2 frames 48.4 ms median; min 47.9, max 63.3 ms
Mouth to ear, wired LANIncluding the browsers’ capture, encoding, buffer and playout. about 90–120 ms with a 1 or 2 frame buffer

Jitter buffer and connection

Per client on the server: it smooths out the network’s unevenness.

ParameterDefaultRange, note
Target depth20 ms of reserve per frame. On a wired LAN 1 is enough. 2 frames (40 ms) 1–10 frames · applies to new connections
Max depthAbove this the oldest audio is dropped so the delay can’t grow. 6 frames from the target up to 20 frames
Adaptive modeHolds about three times the measured jitter, moving at most one frame a second. on the target depth is the minimum
Connection qualityFour bars on the panel, per role in the admin. good · fair · poor good: < 1% loss and < 30 ms jitter; poor: from 5% or 80 ms

Mixing and levels

The admin shows every level in dB; thresholds apply live.

ParameterDefaultRange, note
Gain rangeEvery gain and volume lives in it; its bottom is silent. −48…+24 dB bottom −96…−6, top 0…+40 dB
Input gainPer role and per feed, before any processing. 0 dB within the gain range
Noise gatePer role, with 6 dB hysteresis. off −80…−10 dBFS
Speech thresholdRMS after gain and gate; it starts the ducking. −36 dBFS −80…−10 dBFS; ±24 dB offset per role
Priority duckingWhile a priority role is audibly talking. 12 dB 0–40 dB
Feed ducking“Dim under talk” feeds, under anyone’s speech. 24 dB 0–40 dB
Ducking timing down at once 300 ms hold, 500 ms release
Ducking while talkingAgainst echo at speaker positions. off 0–40 dB
SidetoneYour own voice in the headphones, locally, without delay. off −40…0 dB
Signal threshold (Live matrix)Display only. −36 dBFS −80…−10 dBFS, peak

Keys and signals

How the panel behaves; every value applies live.

ParameterDefaultRange, note
Latch thresholdA shorter press latches, a longer one is momentary. 300 ms 50–2000 ms
Silent talk releaseA latched key that carried no speech for this long. off 0–240 minutes
Call displayThe call sound repeats every 15 s while it shows. 10 s 0–120 s; 0 = until answered
Reconnect graceOn a short drop the latched keys are kept. 10 s —
Key types Single, Multiple, Group, All, Reply, Kill modes: Talk, Listen, Talk + listen
Release tone off BroadTalk, Beep, Click
Profiles Headset Speaker: echo and noise suppression, auto gain

Network

Defaults; all can be changed in the setup or on the admin’s Server page.

ParameterDefaultRange, note
HTTP TCP 5000 start page, CA download
HTTPS TCP 5001 panel, admin, API
Audio (RTP) UDP 60000–60499 encrypted with SRTP
OSC off any UDP port
InternetA public name, a public IPv4 address if needed. TCP 5001 + the UDP range no STUN or TURN; certificate from the machine store, rechecked hourly
Offline fully working nothing is loaded from outside

Security

Comfortable on the LAN, strict from the internet.

ParameterDefaultRange, note
Admin password from the internet at least 12 characters; locked out for 15 minutes after 10 failures
Role PIN 4–12 digits 1 minute lockout after 5 misses, per address; only a hash is stored
Feed PIN required —
Roles from the internet PIN required a role without a PIN cannot connect from outside
Control API API token per device, revocable one by one; the admin password does not open it
HTTPS its own BroadTalk CA or a company certificate; several servers can share one CA

System

Server, clients and load.

ParameterDefaultRange, note
Server Windows a self-contained program with its runtime, installed by a wizard
Clients Chrome, Edge PC, tablet, phone; can go on the home screen
Load test32 endpoints in one group, everyone talking. 32 clients 992 open paths, 0 decoding errors
Data C:\ProgramData\BroadTalk settings, presets, logs, certificates; kept on update
Updates one click the server looks for a new version every six hours
Event log daily files talk, call, mute, connection, configuration, audio engine

Control

Every command acts as if pressed on the panel.

ParameterDefaultRange, note
HTTP API GET or POST key down, up, press; listen, call, mute, ON AIR, preset, Kill, state
OSC UDP the same actions, without a password, on a trusted network
Stream Deck plugin, 5 actions Stream Deck 7.1 or newer; state every half second
ON AIR tally API and OSC a red ON AIR on the role’s panel

Measured on a development machine (Windows 10, the server and the test clients on the same machine); a dedicated server does better.

The settings in detail in the manual (in Hungarian)

A headset on a microphone stand in the studio at night

Contact

Let’s talk.

Questions, a demo, or a trial in your own studio? Write or call, and we’ll show you how BroadTalk fits the way you work.