Engadget Explainer: Amplifiers Can Improve Sound, but Many Users Already Own One

On their own, most audio signals are not strong enough for clear playback, according to the article. A turntable with its speakers disabled demonstrates this through needle talk, the quiet sound of the stylus running along vinyl grooves, which may not even be recognizable as music. All sound systems need an amplifier to increase signal strength before output, and an amp must be matched to the power and impedance specs of speakers, measured in watts and ohms.

Amps do more than raise volume, the explainer said. A quality amp lets users adjust gain, the amount of signal boost, and shape sound through an equalizer, such as adding heavier bass or clearer vocals. Correct gain and EQ settings help prevent clipping, distortion and hardware damage.

Engadget also distinguished amplifiers from preamps. Preamps raise audio to line level for correct gain throughout a system, so an amp is still needed to power speakers. Some amplifiers have a built-in preamp, which streamlines the audio chain.

The article said many consumers do not need to buy an amp at all. Many, if not most, consumer speakers are active and already have integrated amps, as shown by their individual power cords. Only passive speakers require external power sources, and even then a dedicated unit may not be necessary. Receivers often incorporate both amp and preamp functions, making them a one-stop option. Exceptionally power-hungry systems may need an additional amp; for example, elaborate Dolby Atmos setups that exceed the number of channels a receiver can power simultaneously will require one.

For most people, a solid-state amp is a better choice than a tube-based one, Engadget said. Tube models provide a warmer sound and are visually appealing, especially for fans of retrofuturism, but they typically deliver 50W or less apiece, making them unsuited to surround-sound configurations unless a user buys several. Tubes also require more maintenance, including swapping them as they wear out. Running a home theater on tube amps would be an expensive exercise in futility, according to the explainer.

More cost-effective sound upgrades often involve speakers, the article said. A basic stereo soundbar or speaker pair can be replaced with a high-powered, all-in-one Atmos bar. If a user already has that, adding rear and side channels can enhance sound separation. Ceiling channels are the endgame for an audiophile, but they can be more trouble than they are worth because they must be mounted and wired.

Cheaper improvements include using mats or speaker stands to solve unwanted rattling. Acoustic panels can reduce unwanted reverb, and moving speakers farther away from walls can sometimes fix muddy bass. Smart speakers with automatic room calibration should be run whenever a user makes significant space alterations.

Engadget said gear makers will gladly sell many add-ons to improve a sound system, including gold-plated audio cables, although such cables cannot really improve digital audio because a user either gets a clean data signal or does not. An amplifier remains on the short list of products to take seriously, but the article cautioned against automatically buying one alongside a new set of speakers. It advised consumers to understand what an amplifier does, how much it can improve sound quality in the real world and whether a separate one is needed at all.