What is a DAB Multiplex?
The Complete 2025 UK Guide
Simple Answer (No Jargon)
A DAB multiplex (usually just called a “mux”) is the digital “basket” that carries 10–30+ radio stations on one single frequency.
Think of it like a zip file for radio: all the stations are squeezed together, protected against interference, and sent out as one signal. Your DAB radio then unpacks it and lets you choose which station to listen to.
How a DAB Multiplex Actually Works (2025 Tech)
- Each station’s audio is compressed (DAB+ uses the ultra-efficient HE-AAC v2 codec).
- All streams are bundled with error protection using OFDM (Orthogonal Frequency-Division Multiplexing) and convolutional coding.
- The bundle is broadcast on one frequency block (1.5 MHz wide) at ~1,184 kbit/s total capacity.
- Receivers decode the signal and separate the stations – even while moving at high speed.
DAB vs DAB+ – The Table That Changes Everything in 2025
| Feature | DAB (Legacy) | DAB+ (2025 UK Standard) |
|---|
| Audio codec | MP2 | HE-AAC v2 |
| Stereo bitrate (good quality) | 128–192 kbit/s | 40–88 kbit/s |
| Typical stations per multiplex | 9–12 | 18–30+ |
| Mandatory for new UK SSDAB? | No | YES – 100 % of Round 8 |
Bottom line: DAB+ is 3× more efficient. That’s why Ofcom now forces it for all small-scale DAB – more stations, lower costs, better sound.
Real-World UK Examples (2025)
- BBC National DAB – 11 stations on one block, 97 % UK coverage.
- Manchester SSDAB (launched 2024) – 14 local stations, 98 % coverage, ~£20k startup.
- London DAB – 60+ services on three multiplexes.
How Much Does a DAB Multiplex Cost in 2025?
- Join an existing multiplex → £300–£800 per month per station
- Run your own SSDAB multiplex → £15,000–£60,000 startup (most break even in 9–15 months)
→ Use our free 2025 cost calculator
Want Your Own Multiplex?
Round 8 is the final ever chance to apply for a new small-scale DAB area.
SSDAB Round 8 – Final 40 Areas & Countdown →