Bose Soundlink Flex 2nd gen vs Sony ULT Field 5

Last updated: September 26, 2026

These sit in different size classes, so this is not a straight ranking comparison. The Bose Soundlink Flex 2nd gen ranks #35 of 144 medium speakers by sound quality at $159; the Sony ULT Field 5 ranks #44 of 82 large speakers by sound quality at $198.

Bose Soundlink Flex 2nd gen vs Sony ULT Field 5

The case for the Bose Soundlink Flex 2nd gen: A very portable 586g, IP67-rated speaker with a clear, well-balanced midrange that keeps voices and instruments intelligible. Watch for: One Flex remains mono and cannot deliver genuine low-bass rumble; RTINGS also found the elevated treble can turn hi-hats and other high-frequency detail piercing.

The case for the Sony ULT Field 5: A tough 3.3kg portable with IP67 protection, LDAC/AAC support, aux input, a 10-band app EQ, Party Connect, USB-C power-bank output and a claimed 25-hour battery. The tradeoff: It prioritizes bass and loudness over fidelity: reviews find the upper mids and highs subdued, with limited stereo separation and soundstage depth.

Buy the Bose Soundlink Flex 2nd gen at $159 if you want a medium speaker. Buy the Sony ULT Field 5 at $198 if you want a large speaker instead.

There is a real battery-life gap here: the Sony ULT Field 5 is rated for 25 hours, the Bose Soundlink Flex 2nd gen only 12 hours.

Looking for alternatives? See the complete Portable Bluetooth rankings.

Buy the Bose Soundlink Flex 2nd gen at Amazon ($159.00) →Buy the Sony ULT Field 5 at Amazon ($198) →

Specifications Side By Side

Bose Soundlink Flex 2nd gen Sony ULT Field 5
Price$159.00$198
Ranked#35 of 144 in Medium Size Portable Bluetooth Speakers#44 of 82 in Large Size Portable Bluetooth Speakers
AppYesYes
Battery Life12 hours (Manufacturer specified)25 hours (Manufacturer specified)
Built-in MicrophoneYesYes
EQYes (3 band)Yes (App + ULT button)
IP RatingIP67IP67
Party ModeYes (Bose Party mode)Yes (Party Connect up to 100 speakers)
Power InputUSB-CUSB-C
StereoNoYes
OmnidirectionalNoNo
TWSYesYes
Weight1.3 lbs (586 g)7.3 lbs (3.3 kg)
Bluetooth Version5.35.3
Dimensions7.9” x 3.5” x 2” (201 x 90 x 52 mm)12.6” x 5.7” x 4.9” (320 x 144 x 125 mm)
Aux InputNoYes
Drivers60mm full-range driver with passive radiators2x 46mm tweeters + 1x 79mm x 107mm woofer
Bluetooth CodecsSBC, AAC, aptX AdaptiveSBC, AAC, LDAC
Digital Aux InputNoNo
StrapYes (built-in loop)Yes (detachable shoulder strap)
Power Bank-Yes (USB-C)
Amplifier Power-27W
Buy the Bose Soundlink Flex 2nd gen at Amazon ($159.00) →Buy the Sony ULT Field 5 at Amazon ($198) →

How Bose Soundlink Flex 2nd gen compares with other leading options:

Prices on this page were last checked September 26, 2026 at 11:14 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.

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The Two Speakers In Full

Bose Soundlink Flex 2nd gen ranking card

Older model: the Bose Soundlink Flex (rated 3.8/5).

Pros: A very portable 586g, IP67-rated speaker with a clear, well-balanced midrange that keeps voices and instruments intelligible. The second generation adds a Bose app with 3-band EQ, better-placed controls and stereo pairing with another Bose Soundlink Flex 2nd gen. It supports AAC and aptX Adaptive in addition to SBC, making it a stronger wireless option than most small rivals.

Cons: One Flex remains mono and cannot deliver genuine low-bass rumble; RTINGS also found the elevated treble can turn hi-hats and other high-frequency detail piercing. The claimed battery life is only 12 hours, and some owners report accelerated standby drain after firmware updates. It is expensive for its size, so the added app and codec support, not a transformational sound upgrade over the original, are the main reasons to choose it.

Full Bose Soundlink Flex 2nd gen review and specifications →

AppYes
Aux InputNo
Battery Life12 hours (Manufacturer specified)
Bluetooth CodecsSBC, AAC, aptX Adaptive
Bluetooth Version5.3
Built-in MicrophoneYes
Digital Aux InputNo
Dimensions7.9” x 3.5” x 2” (201 x 90 x 52 mm)
Drivers60mm full-range driver with passive radiators
EQYes (3 band)
IP RatingIP67
OmnidirectionalNo
Party ModeYes (Bose Party mode)
Power InputUSB-C
StereoNo
StrapYes (built-in loop)
TWSYes
Weight1.3 lbs (586 g)
Check current price at Amazon ($159.00) →Search eBay for Bose Soundlink Flex 2nd gen →

Sony ULT Field 5: $198 Amazon eBay

Sony ULT Field 5 ranking card

Older models: the Sony SRS-XB43 (rated 3.5/5) and the Sony SRS-XG300 (rated 3.1/5).

Pros: A tough 3.3kg portable with IP67 protection, LDAC/AAC support, aux input, a 10-band app EQ, Party Connect, USB-C power-bank output and a claimed 25-hour battery. Reviews find it energetic and dynamic with substantial bass, enough volume for a yard, and two ULT modes that let bass-focused listeners choose a deeper or punchier presentation.

Cons: It prioritizes bass and loudness over fidelity: reviews find the upper mids and highs subdued, with limited stereo separation and soundstage depth. Deep bass is less authoritative than the enclosure suggests, and the loud confirmation tone when pressing the ULT button is an unnecessary annoyance. Use the app EQ and audition it before buying for detail-focused music.

Full Sony ULT Field 5 review and specifications →

Amplifier Power27W
AppYes
Aux InputYes
Battery Life25 hours (Manufacturer specified)
Bluetooth CodecsSBC, AAC, LDAC
Bluetooth Version5.3
Built-in MicrophoneYes
Digital Aux InputNo
Dimensions12.6” x 5.7” x 4.9” (320 x 144 x 125 mm)
Drivers2x 46mm tweeters + 1x 79mm x 107mm woofer
EQYes (App + ULT button)
IP RatingIP67
OmnidirectionalNo
Party ModeYes (Party Connect up to 100 speakers)
Power BankYes (USB-C)
Power InputUSB-C
StereoYes
StrapYes (detachable shoulder strap)
TWSYes
Weight7.3 lbs (3.3 kg)
Check current price at Amazon ($198) →Search eBay for Sony ULT Field 5 →