Speakers

A 100V line speaker has a transformer with power taps, so many speakers can share one amplifier over long cable runs; an 8 ohm speaker connects straight to a low-impedance amplifier output and suits a few speakers close by. Some models switch between the two, such as the Adastra 952.430UK pendant, listed as 100V/8 Ohm.

Choose by room height, the coverage needed and the system: 100V for a shop or office, 8 ohm for a home or small bar. The Adastra KV-T 952.282UK is an 8in 100V model rated 40W, the SL Series 952.546UK is a slimline 8 ohm speaker with 160° dispersion, and the 952.138UK is a 3in metal ceiling speaker for bathrooms.

Active suits a quick portable setup, and passive suits speakers driven by an existing amplifier rack. Active cabinets such as the Citronic CAB Series 178.010UK have the amplifier, Bluetooth and controls built in, while passive cabinets such as the 178.011UK connect by speaker lead to a power amplifier or powered mixer.

An 8in cabinet for speech and small functions, a 12in cabinet for bars and mobile discos, and a 15in cabinet for bands and larger halls. In the Citronic range those sizes are the CASA 178.108UK, 178.112UK and 178.115UK. Add a subwoofer when the music needs deep bass.

Yes, with a driver that matches the size, impedance and power of the original. QTX lists QR Series replacements such as the 902.521UK (12in, 8 ohm, passive) and 902.522UK (30cm, 4 ohm, active), and Citronic lists woofers, sub drivers and titanium HF compression drivers such as the 902.114UK (44mm, 60W RMS).

A crossover splits the signal so low frequencies go to the woofer and high frequencies to the tweeter or horn. QTX passive 2-way crossovers include the 900.591UK, rated 200W at 3kHz and 8 ohms, and the QTX 900.582UK passive subwoofer filter crosses over at 120Hz for a 4 ohm sub.

Use speakers certified to EN54-24. Examples include the Adastra 952.205UK fire dome ceiling speaker, the Adastra F40V 952.244UK outdoor column rated IP66, the Penton RCS4FT/ENC 4in ceiling speaker and the TOA CS-154BS horn. A voice alarm system also needs a compliant amplifier and cabling, so check the system specification before choosing speakers.

Yes. Vanco in-ceiling speakers such as the IC8-BSC, with an 8in woven cone and 80W rating, suit home audio, the Adastra BC Series 100.904UK pair is a 5.25in 8 ohm stereo background speaker, and the AV:Link 120.150UK active bookshelf speakers play over Bluetooth 5.0 or from USB and micro SD.

A portable PA combines a speaker, an amplifier and often wireless microphones in one unit that can be wheeled or carried to events, schools and fitness classes. The QTX 178.840UK is a 10in trolley-style unit with a VHF wireless neckband mic and 50W output, and the QTX 178.839UK runs from mains or a rechargeable battery, pairs over Bluetooth and has a VHF wireless receiver built in, with a VHF handheld microphone included.