Two components make up the foundation of any hi-fi system: the speakers and the power amplifier to properly drive them. If you want to create a vinyl hi-fi system, you'll also need a turntable and a phono preamplifier, but neither is anything without a speaker and power amplifier.
Power amplifiers don't always go by that name. Imbued with extra features, they're sometimes called receivers (amplifiers with wireless capability from radio to Wi-Fi) or integrated amplifiers (amplifiers with a built-in phono preamp for your turntable). But they're primary job is the same: take a weak audio signal and boost it so it's powerful enough to drive a speaker.
Pairing an amp to a speaker is the cornerstone of hi-fi nerdery, with all sorts of logics to govern your choices. But it's also possible to get objectively wrong. An amp needs to be powerful enough to drive the speakers it is paired with, as well as match-up the impedance (measured in ohms) so that the speaker-and-amp combination will work and sound best — and it all gets a little bit complicated.
So to get you started here are five pairs of passive bookshelf speakers, along with an amplifier that's capable of driving them to their full potential.
Speakers: Q Acoustics 3020i
The Q Acoustics 3020i is one of our favorite entry-level pair of bookshelf speakers. The U.K.-based audio company released the 3020i in 2018, and they are essentially an all-around better version of the previous 3020. They're slightly slightly taller and have a 25-percent deeper chamber, which gives the 3020i significantly more powerful bass despite being smaller speakers. Now almost two-years-old, you can often snag a pair of 3020i bookshelf speakers for less than $300.
Amplifier: Cambridge Audio AXA35
The AXA35 is one of the best affordable amplifiers you can buy. It's a two-channel integrated amplifier with an integrated phono preamplifier, which gives you the flexibility to add a turntable to your setup down the road. It's also able to power 35-watts per channel, which is plenty enough to power a good entry-level pair of bookshelf speakers like the Q Acoustics 3020i. The downside is that the AXA35 doesn't support Bluetooth or Wi-Fi, so you'll need another component if you want a streaming system.
Speakers: Klipsch Reference R-51M
The R-51M are the most affordable speakers in Klipsch's high-quality Reference line. Each speaker features a 5.25-inch driver along with Klipsch's signature Tractrix horn tweeter and, together, the pair are able to deliver rich, room-filling sound with deep bass. In addition to being some of the best-sounding and bang-for-your budget bookshelf speakers you can buy, it's really their cool, retro flair that make the Klipsch R-51M unforgettable.
Amplifier: Onkyo A-9110
The Onkyo A-9110 is a two-channel integrated amp that's able to deliver 100-watts of total power (50-watts per channel), and it pairs nicely with the Klipsch R-51M without the need of worrying about blowing them out (the Klipsch R-51M can handle up to 85-watts of power). Additionally, the Onkyo A-9110 has loads of connectivity options — four analog RCA inputs, a phono input with a MM phono equalizer, an analog RCA line-level output and a subwoofer pre-out — in case you want to built out your system down the road.
Speakers: KEF Q150
The Q150 review are the smallest and most affordable speakers in KEF's Q series. Each speaker features a unique Uni-Q driver — which consists of a centered tweeter-and-woofer combo, instead of two separately mounted drivers, resulting it a more direct and accurate sound — that's similar to ones found in KEF's more expensive lines. The Q150 also have a nominal impedance of 8 ohms, making them fairly easy to drive for most amplifiers. If you're looking for a more refined sound compared to most "entry-level" passive bookshelf speakers but don't want to take out a loan, these are all-around great speakers.
Amplifier: Yamaha WXA-50 MusicCast
Yamaha's WXA-50 is a beautiful two-channel stereo amplifier that can deliver up to 70-watts per a channel, which is more than enough to power KEF's Q150. The big advantage of the WXA-50 is that it's a wireless streaming amplifier with loads of connectivity options. It works with the MusicCast app and can be integrated into any MusicCast multi-room speaker system. It also has built-in Bluetooth, so you can stream music directly to the system directly from your smartphone or computer, too.
Speakers: Bowers & Wilkins 606
The B&W 606 are definitely on the high-end, but they're also some of the best-sounding and most dynamic bookshelf speakers you're likely to find. They feature B&W's Continuum cone driver technology, which has been a signature feature of the company's higher-end speakers for years. And both speakers have a rear-firing port that helps the speakers deliver surprisingly punchy bass. If you're a true music lover and you have a bigger room to set up your system (these get loud), the B&W 606 are fantastic compact speakers.
Amplifier: Rega Brio
Rega, the UK hi-fi manufacturer, is well known for making highly musical amps. The Brio, for example, is a fantastic integrated amp that's capable of driving some of the more powerful and sensitive speakers. It lacks streaming support, so it might not be the perfect fit for those building and new-age digital/analog system. But it does have an excellent built-in phono stage that pairs superbly with Rega's high-end turntables.
Speakers: Polk Audio Legend L100
With Polk Audio's Legend Series, you're entering true audiophile territory. The L100 speakers have a finely tuned 1-inch pinnacle tweeter and a proprietary 5.25-inch Turbine Cone midrange/bass driver, the combination of which results in an ultra-detailed sound. The frequency range is incredibly wide, too. You're getting lows in the 50Hz range and highs up near 50kHz. These speakers, if you can afford them, are incredible.
Amplifier: Sonos Amp
The Sonos Amp is a beast. It's capable of driving 125-watts per channel, which should be more than enough to drive the Legend L100 (Polk recommends driving the L100s with 70 watts per channel, although they can handle up to 160 watts of peak power). The Amp is a great amp if you already have several Sonos speakers, because it allows you to integrate your non-Sonos speakers into your existing Sonos multi-room system -- so you can play music on all your speakers at once. Additionally, the Amp has an HDMI ARC port, which allows you to connect your passive bookshelf speakers to your TV, just like a Sonos's Arc or Beam soundbars.