Sonos Playbase (see image) is more geared towards home theatre use. Sonos Five is more for listening to music.
Summary
Since these are Sonos speakers, expect brilliant, dynamic sound. We prefer Sonos Five configured with two speakers for dazzling audiophile performance while designating Playbase for an immersive home theater experience. Note that Sonos Five replaces Play:5 (Gen 2). On 6 August 2020, Sonos discontinued (but still supports) Playbase.
Sound Quality
Let me tell you something right off the bat.
Room acoustics, particularly room dimensions and speaker positioning, will have an immense effect on sound quality.
The impact of the combination of these two is actually so strong that in most cases, it doesn't even make sense to utter a single word on sound quality without speaking of them.
This is why I'd hiiiiiiighly recommend you to check out this simple, 2D, online speaker placement calculator. I've had an Acoustics & Audio PhD build this tool specifically for this purpose. It's also completely free and mobile compatible. It's GOOOOLLLDDDDD.
ASAP Science made a video on the loudest and quietest rooms in the world. A mind blowing example of the importance of acoustics (time adjusted video).
Other parameters such as the age/materials of the building, the furniture & carpets in place, ceiling height, etc can and will, of course, have an effect on room acoustics, too. But much less.
Anyways...
No matter what model, Sonos speakers deliver vividly clear and dynamic sound with deep, vibrant bass. Both Five and Playbase fill a room with sound from one speaker. If cost is no object, one has the option of adding two Sonos Five speakers as rears to the Playbase to engulf the viewer in a truly dazzling home theater experience.
To be clear, the award-winning Sonos Playbase is a soundbar mounted or placed under a TV. In praising the Playbase's performance, Tom's Guide reviewer Michael Gowan stated, "The bass adds resonance to dialogue when watching movies or TV shows—without a subwoofer." He added, "The Playbase's strengths in home theater also translate to music."
Sonos Five, released on 8 June 2020, is designed with the audiophile in mind. While it can be configured for home theaters, Sonos warns that "the line-in isn't designed for use with a TV and will result in some latency or lip sync issues while the audio is converted from analog to digital."
Note that when orienting Sonos Five horizontally, the speaker automatically separates the stereo channels. Should a listener pair two Five speakers, each automatically conforms to mono for more distinct stereo separation and an even greater expansive soundscape.
Sonos Five (see image) maintains sound quality even at the highest volume.
Loudness & Power
You'll have no issues with the loudness from either Sonos Five or Playbase. Max Mutter and Michelle Powell of GearLab report that "even in an 800 ft2 room with high ceilings, this speaker (can) get uncomfortably loud. Impressively, it (can) maintain all of its clarity and quality, even when pushing the volume to the maximum."
Likewise, Gowan found that the Sonos Playbase "filled (his) living room with sound, and (was) plenty loud for most viewing situations." Playbase also has a "Night Sound" option that reduces TV volume while retaining proper balance and range. "Night Sound" enhances quiet sounds and reduces the intensity of loud sounds.
Both Sonos Five and Playbase utilize an auto-switching 100-240 VAC, 50-60 Hz universal input power supply. Additionally, Playbase requires a lithium-ion polymer (LiPo) battery.
Features
Weighing 21.5 lbs (9.8 kg) and measuring 2.2 x 28.35 x 15 in (53 x 720 x 380 mm), Sonos Playbase features 10 Class-D digital amplifiers and 10 amplified speaker drivers—6 midrange, 3 tweeters and 1 woofer. It also has a 10/100 Mbps Ethernet port. Like all Sonos speakers, it uses an 802.11 b/g/n (2.4 GHz) WiFi network connection. Too, your TV must have an optical audio output. Also, the Sonos app is required to operate both speakers.
The "tale of the tape" for Sonos Five has the speaker weighing 14 lb (6.36 kg) and measuring 14.33 x 8 x 6 in (364 x 203 x 154 mm). Powered by 6 Class-D digital amplifiers, Five comes with 3 tweeters and 3 mid-woofers. It too has a 10/100 Mbps Ethernet port to connect with a router or a network-attached storage (NAS) device.
Here we should mention that while Playbase works with either the Sonos S1 or S2 app, Five must use the S2 app. That means if one wants to pair Five speaker(s) with the Playbase, then the S2 app is required for both. Merely delete the S1 app from your Playbase and download the S2 app, available at the App Store for iOS and Play Store for Android.
While we love both products, we decry the lack of an HDMI interface for either. There's no Bluetooth (BT or BLE) either though Sonos Five pairs with a mobile device using BLE for initial setup. However, while Playbase has an optical digital audio connection, Five offers an analog stereo 1.8 in (3.5 mm) audio port and a "join" button to connect during setup.
Looks
Both Sonos Five and Playbase are available in either white or black matte exposure, and Five comes with a graphite grille. As a rule, Sonos products have a minimalist aesthetic since controls are usually performed through the Sonos app. For example, the app adjusts EQ settings such as loudness, bass and treble.
However, each has touch controls for volume control and to play or pause music. On the Sonos Playbase, swipe between touch controls to move forward to the next selection or go back to hear the previous track. Both have status indicator lights that can be turned off using the app.
The Verdict
Both Sonos Five and Playbase deliver unsurpassed sound without distortion, even at high volumes. We prefer Sonos Five for our CDs, particularly in a multi-speaker setup, and Playbase for home theater—but you'll enjoy the sound from both in either application.
Lastly, here are some good individual video reviews of the two: