How to read Product DNA

Sensitivity is the level a speaker produces at 1 m from 1 W (or 2.83 V). Every +3 dB halves the amplifier power needed for the same loudness: a 91 dB speaker needs about half the power of an 88 dB one.

Impedance is the speaker's AC resistance, typically 4, 6 or 8 Ω. The lower it is, the more current the amplifier must deliver. The speaker's nominal impedance should not be below the amplifier's minimum rated load: 4 Ω speakers are not recommended on a '6 Ω minimum' amplifier.

A bass reflex port is a tube in the cabinet that reinforces low-frequency output. Rear ports are sensitive to wall distance: too close and the bass can boom, so move the speaker out (about two port diameters) or fit a foam bung. Front and down-firing ports are less placement-critical.

A sealed cabinet has no port. Its bass rolls off more gently and is usually tighter, but less deep than a ported box of the same size; sealed speakers are less fussy about wall distance.

Class A keeps the output devices always on: lowest distortion, but hot and inefficient. Class AB is the common Hi-Fi compromise. Class D is a switching design with high efficiency: compact, powerful, runs cool. The class alone does not decide sound quality — the specific circuit and power supply matter more.

A tube amplifier usually has less power than a transistor one and suits sensitive speakers (88–90 dB and up). Many models have separate 4 Ω and 8 Ω taps — connect the speakers to the tap that matches their impedance. Triode and ultralinear modes differ in power and presentation.

Damping factor is the ratio of load impedance to the amplifier's output impedance. The higher it is, the better the amplifier controls the woofer and the tighter the bass; above roughly 50–100 audible differences are small, and the cable and speaker matter more.

MM (moving magnet) is the most common cartridge type, about 3–5 mV output, works with any MM phono stage; the stylus is usually replaceable. MC (moving coil) outputs far less (0.2–0.5 mV) and needs a phono stage with an MC input or a step-up transformer.

A cartridge's signal is tiny and recorded with RIAA equalisation (bass cut, treble boosted), so a phono stage is needed to amplify it and restore the balance. It can be built into the turntable, the amplifier (PHONO input) or be a separate box. Use exactly one, never two in series.

Auto-stop halts the platter at the end of a side; auto-return also parks the tonearm. Without auto-stop the stylus stays in the run-out groove and the platter keeps spinning until you lift the arm with the cueing lever and stop the motor. It does not damage the record, but do not leave the stylus there for long.

The cueing lever gently lowers and raises the tonearm so the stylus does not drop onto the record. Use it to place the stylus and to lift it at the end of a side.

During play the tonearm is pulled towards the record centre (skating force). Anti-skating compensates it; it is usually set equal to the tracking force so the stylus loads both groove walls evenly.

Tracking force is the weight with which the stylus presses on the record; the cartridge maker specifies it (e.g. 1.8–2.2 g) and it is set with the counterweight. Too little causes distortion and skipping, too much accelerates wear. The cartridge plus headshell mass must fit the tonearm's range.

Speakers with two pairs of terminals can have the bass and treble sections fed by separate cables from one amplifier (bi-wiring) or from two amplifiers/channels (bi-amping). Normally the terminals are joined by jumpers. The gain from bi-wiring is usually small; remove the jumpers before wiring separately.

A and B outputs let you connect two speaker pairs and switch between them. Running A+B together raises the load on the amplifier, so makers usually require a higher impedance per pair (e.g. 8 Ω minimum) — check the minimum load for two pairs.

Pre-Out is the preamp output for an external power amplifier or an active subwoofer. Main In / HT Bypass feeds the power stage directly, bypassing the volume control: this lets a stereo amplifier drive the front channels of a home theatre while the AV receiver controls the volume.

LFE is the separate low-frequency effects channel in films. A subwoofer connects to the amp's or receiver's Sub Out with an RCA interconnect or, if there is none, to the sub's high-level (speaker) input. Set the sub's crossover slightly below the main speakers' lower limit.

HDMI ARC (audio return channel) lets the TV send sound to the amplifier over the same HDMI cable, and CEC lets the TV remote control the volume. eARC carries more channels and high-resolution formats. Use the TV port labelled ARC/eARC.

A DAC (digital-to-analogue converter) turns the digital signal from a computer, TV, streamer or CD transport into analogue. Many amplifiers have one built in (USB, optical, coaxial inputs); it can also be a separate box. If the amplifier has no DAC, digital sources connect via an external one.

DAC filters differ in how they cut frequencies above the audible band: Fast rolls off steeply, Slow starts lower and more gently, minimum-phase removes pre-ringing. The differences are subtle; choose by ear.

DSD is a one-bit recording format. DoP sends DSD packed inside a PCM stream and works with almost any DSD-capable DAC; native DSD sends it directly but needs a driver (ASIO on Windows). There is no audible difference — only the maximum supported rates differ.

AirPlay streams audio from Apple devices over Wi-Fi. AirPlay 2 adds multiroom playback and more robust buffering. Chromecast does the same for apps with Google Cast support, including on Android.

Connect protocols (Spotify Connect, Tidal Connect) let you pick the streamer inside the service's app: music flows from the internet to the streamer directly, the phone is just a remote. Roon Ready means support for the paid Roon system; UPnP/DLNA plays from a home server or NAS. Service availability in Russia changes — check the current status.

The codec sets Bluetooth audio quality. SBC is universal; AAC works best with iPhones; aptX and aptX HD are on many Android phones; LDAC has the highest bitrate. The codec both ends support is used.

A balanced (XLR) link sends the signal on two conductors in opposite phase, and the receiver cancels picked-up noise. It helps on long runs and noisy setups; over short home distances RCA works just as well with well-made equipment.

The longer the run and the lower the speaker impedance, the thicker the cable must be so its resistance does not eat power and bass control. For home runs up to 5 m 2.5 mm² is usually enough, longer runs take 4 mm²; the minimum is about 1.5 mm². The cable must suit the terminals (bananas, spades, bare wire).

Warm-up is the time after power-on for an amplifier to reach its operating point (noticeably longer for tube and class A designs). Burn-in is the change in new drivers over the first tens of hours as the suspensions loosen. No special procedure is needed: just play music at normal levels.

For an amplifier what matters is continuous (rated) power into 8 and 4 Ω. For speakers, the 'recommended amplifier power' is the range the maker suggests, and peak power is a short-term limit. A little headroom in amplifier power helps control the speakers.

Tone controls lift or cut bass and treble; loudness adds bass and treble at low volume. Direct mode bypasses these circuits for the shortest signal path — use it when no correction is needed.

In a coaxial driver the tweeter sits at the centre of the woofer, so both bands radiate from one point. This gives more precise imaging and more even off-axis sound; KEF's Uni-Q is an example.