The Sony ULT TOWER 9AC is the second largest of the party speakers in the brand's ULT POWER SOUND series. The sizable speaker on wheels houses seven speakers: four tweeters, two for mid-range frequencies, and a large 320 mm (12.6") woofer for supplying the bass, and it promises 360-degree sound and room correction. Kitted out with two 1/4" inputs for mics or guitars, audio effects like echo, and a customizable lightshow, it's poised as your next one-stop party solution, so long as you have a power outlet nearby.
Our Verdict
The Sony ULT TOWER 9AC is good for listening to music. For the bassheads, it provides extra low-end boost by default via the 'ULT' sound modes, so you feel the rumble, and it plays back in stereo without downmixing. If you're not fond of heavy lows, you can play around with the app's EQ for more detail in the treble, and it gets plenty loud. Two mic inputs (or one mic input and a guitar input) mean you don't need to go to the bar for a karaoke performance. Plus, sound and lighting effects add some extra ambiance. The controls are intuitive and comprehensive for playback, effects, input selection, and more. Pairing a second device allows seamless control, and LDAC is available for higher-resolution audio. Outside of Bluetooth, an AUX input and an Optical input are available. On the downside, it might be overkill for some people's needs due to its size, and by itself, the speaker's sound is sensitive to listening angles.
Tuned for bassheads.
Intuitive and comprehensive controls and app.
Flexible connectivity for mics, guitar, Bluetooth, and wired audio.
Gets loud enough to fill most spaces.
Despite the wheels, it's not very portable.
How it sounds is fairly affected by your listening angle.
The Sony ULT TOWER 9AC is alright for videos and movies. Connectivity is a bit upgraded from most speakers: if you have a TV or video projector, it uses an Optical input, which is pretty unusual for a party speaker. There's also a standard AUX input for added flexibility. Bluetooth latency with iOS devices is quite low and ought to sync A/V relatively well, while Android latency is elevated and could lead to lip sync mismatch. Its frequency response can deliver the low rumble and boom necessary for an immersive experience, though the speaker is sensitive to directivity and requires good placement. Depending on the size of the space and the audience, it'll offer a reasonably good movie experience in a pinch (so long as you're not counting on surround sound and Atmos), but if you're airing an outdoor movie to a larger crowd, some of the audience may have trouble picking out dialogue if they aren't facing the speaker.
Intuitive and comprehensive controls and app.
Optical and AUX inputs for video sources.
Gets loud enough to fill most spaces.
Despite the wheels, it's not very portable.
How it sounds is fairly affected by your listening angle.
Bassy default tuning can affect the the clarity of voices.
The Sony ULT TOWER 9AC is middling for podcasts. You can certainly use it for listening to your favorite podcasts, but it's also overkill for most people. Its cumbersome size and the necessary power outlet limit where you can take it, though to be fair, its massive volume output is loud enough that whatever you play in one room will very likely reach another room. Still, despite the tweeters facing the back of the speaker, the sound is fairly susceptible to directivity, which impacts the balance and clarity of higher register sounds like voices if you aren't facing the front of the tower. That said, you can connect it to multiple devices simultaneously, which adds one small layer of convenience.
Intuitive and comprehensive controls and app.
Despite the wheels, it's not very portable.
How it sounds is fairly affected by your listening angle.
Bassy default tuning can affect the the clarity of voices.
The Sony ULT TOWER 9 doesn't support a voice assistant.
The Sony ULT TOWER 9AC isn't ideal for outdoor use because it needs an electrical power outlet, which limits where you can use it. You can certainly wheel it into your backyard with an extension cord, but it's also not weatherproof, so be aware of the forecast if you take it outside.
Changelog
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Updated Feb 20, 2026:
We've mentioned the JBL PartyBox 720 in the Battery box of this review.
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Updated Aug 14, 2025:
The Frequency Response Accuracy box was updated to mention the flatter tuning of the JBL PartyBox 520.
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Updated Jul 10, 2025:
We've updated the Dust and Impact resistance rating in the Build Quality section of this review from 'No' to 'Unspecified' due to the lack of information on the manufacturer's website.
- Updated Jun 18, 2025: Review published.
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Differences Between Sizes And Variants
The Sony ULT TOWER 9AC only comes in one color, 'Black.' Here's a photo of the label for our unit. There's a battery-powered version called the Sony ULT Tower 9 (without 'AC'), and while we expect some functions are similar, like the app and controls, other performance metrics may vary from the AC model, so our results are only valid for our unit.
If you encounter another variant, please let us know in the comments, and we'll update our review.
Popular Speaker Comparisons
Once the job of several pieces of audio equipment and their associated cables, party speakers are the all-in-one answer to pop-up events and DIY karaoke venues. Party speakers like the Sony ULT TOWER 9AC combine a little bit of everything like a Swiss Army knife, so while a single speaker isn't a true substitute for a proper PA or sound system, its appeal is its ease of use and flexibility. The JBL PartyBox 710 is roughly the same size and weight as the Sony, and both reach a similarly loud max volume. However, if you want something smaller, the JBL PartyBox Stage 320 weighs almost half of the other two. The PartyBox 710's frequency response is a little more balanced by default, but arguably, the Sony's bassy emphasis may be more appealing, while the PartyBox Stage 320 sounds decidedly brighter than either. Still, these Bluetooth-capable stereo speakers include EQ in the app, as well as mic and guitar inputs, so you have similar options in this regard.
One limitation of both the Sony and PartyBox 710 speakers is that they're not battery-powered, whereas the PartyBox Stage 320 can last 23 hours on a single charge. If you want something even smaller, the Bose S1 Pro+ weighs roughly a quarter of the Sony's heft. While the Bose isn't as loud—it's still pretty loud—or thumpy in the bass compared to the Sony, unlike the other speakers in this comparison, you can carry it single-handedly, and its battery lasts around 10 hours. Basically, it's up to you and your specific Goldilocks use case.
To remedy decision paralysis, check out the best speakers for parties, the best speakers for karaoke, and the loudest Bluetooth speakers.
The Sony ULT TOWER 9AC is a less portable party speaker alternative to the JBL PartyBox 720. As the name implies, the Sony only runs off AC power, which limits its usage to indoor locations and outdoor locations that can be reached with a power cord. Looking past this, there still aren't many reasons to favor the Sony. It has a similar top volume to the JBL, with worse directivity and a less balanced sound that cranks the bass range for a boomy sound. Both are solid options for your next karaoke event, but the JBL has a bit more versatility for outside use.
Choosing between the JBL PartyBox 710 and Sony ULT TOWER 9AC comes down to preferences for most people because they're similarly large and hefty. If you want a balanced sound with less compression in the bass and better directivity, the JBL slightly wins out. It's also IPX4-rated, while the Sony's control panel is apparently splashproof-only. Connectivity is fairly similar: mic and guitar inputs, wired via an AUX cable, Bluetooth, and each supports stereo and party modes with compatible speakers. The Sony offers the LDAC Bluetooth codec, which is a step above the JBL, and an Optical port for TVs. Still, it may come down to something as simple as which one has a bassier tuning (the Sony) or which one's app interface you prefer.
The Sony ULT TOWER 9AC and JBL PartyBox 1000 have different strengths. While both are large and loud speakers with comprehensive apps that include EQ, the Sony plays back audio in stereo, whereas the JBL downmixes to mono unless you buy a second identical speaker. The Sony also weighs less and is easier to move. Besides similar Bluetooth and mic inputs in common, the Sony includes an Optical port, while the JBL uses RCA. The Sony sounds notably bassier by default, while the JBL's frequency response is more balanced out of the box, and it compresses less at full volume. Other differences are more niche, such as a DJ effects pad on the JBL.
The JBL PartyBox Stage 320 is an optionally battery or A/C-powered speaker that weighs nearly half of the larger, Sony ULT TOWER 9AC. Its frequency response is more balanced, but it doesn't have as much low-end as the Sony. However, it compresses less at max volume, and despite its smaller size, it still gets very loud. Its controls are straightforward and focus on audio playback, while the Sony includes direct controls of the lights. Both include mic and guitar inputs and similar Bluetooth and wired connectivity, although the JBL has a wired line out, which is handy for adding any speaker with a line-in, and the Sony includes Optical input for connecting a TV or projector. On the other hand, if you're into bassy tuning, the Sony is the way to go. Like the JBL, it gets loud and it's quite bassy. That said, you need a power source nearby to use it.
Test Results
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