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 decent for listening to music. For the bassheads, it provides extra low-end boost via the 'ULT' sound modes, so you feel plenty of rumble, though it also means mixes can sound overly boomy. If you're not fond of heavy lows, you can play around with the app's EQ to add more detail to the treble, and it gets remarkably 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. Unfortunately, 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, so you only hear the best audio if you're positioned in front of it.
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.
Poor directivity.
Bassy default tuning can reduce vocal clarity.
The Sony ULT TOWER 9AC is acceptable 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. 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.
Poor directivity.
Bassy default tuning can reduce vocal clarity.
The Sony ULT TOWER 9AC is middling for podcasts. You can certainly use it to listen to your favorite podcasts, but it's overkill for most people. Its cumbersome size and the required 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. Still, even with the tweeters facing the back of the speaker, voices sound muffled when you're behind it. 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.
Poor directivity.
Bassy default tuning can reduce vocal clarity.
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
- Updated Jul 28, 2026: This review has been updated to Test Bench 1.0.1. This includes the Test Bench 1.0 updates to all of our Sound tests: Frequency Response Accuracy, Raw Frequency Response, Directivity, and Loudness, as well as the revised Low-Frequency Extension calculation and related DRC updates introduced in Test Bench 1.0.1. There have also been text changes throughout the review, including to the usages and product comparisons, where applicable, to match these results. You can read more about these changes in our Test Bench 1.0 changelog and Test Bench 1.0.1 changelog.
-
Updated Jul 24, 2026:
We referenced the SOUNDBOKS Mix in the Portability box.
- Updated Jul 13, 2026: This review has been updated to Test Bench 1.0, which includes new results for all of our Sound tests: Frequency Response Accuracy, Raw Frequency Response, Directivity, and Loudness. There have also been text changes made throughout the review, including to the usages and product comparisons, to match these results. You can read more about these changes in our changelog.
-
Updated Feb 20, 2026:
We've mentioned the JBL PartyBox 720 in the Battery box of this review.
Check Price
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 lies in 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 as much as the other two and still gets very loud, albeit not as ear-shatteringly so. While neither the Sony nor the PartyBox 710 speakers are battery-powered, the PartyBox Stage 320 can last 23 hours on a single charge. Basically, it's up to you and your specific Goldilocks usage.
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 speaker runs only on AC power, limiting its use to indoor locations and outdoor areas reachable 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. That said, the Sony does offer more balanced and well-controlled mid and treble ranges, so sounds like voices are reproduced more accurately. 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. They also offer very similar frequency responses. The JBL is IPX4-rated, while the Sony's control panel is apparently splashproof-only. But 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 speaker offers the LDAC Bluetooth codec, which is a step above the JBL, and an Optical port for TVs. The Sony speaker also gets a touch louder.
The JBL PartyBox Stage 320 is a smaller, more portable alternative to the Sony ULT TOWER 9AC. It weighs nearly half as much and can run on either battery or AC power, while the Sony needs a nearby power source. Both speakers have mic and guitar inputs, along with similar Bluetooth and wired connectivity. The JBL also has a wired line out, which is handy if you want to add another speaker with a line-in, while the Sony has an Optical input for connecting a TV or projector. The JBL's controls are more focused on audio playback, while the Sony adds direct controls for its lights. The larger Sony gets much louder, but the JBL is easier to place and move around.
The Sony ULT TOWER 9AC and JBL PartyBox 1000 have different strengths. While both are large, 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 speaker also weighs less and is easier to move. Besides similar Bluetooth and mic inputs, the Sony includes an Optical port, while the JBL uses RCA. The Sony sounds more balanced out of the box and gets a bit louder. Other differences between the speakers are more niche, such as a DJ effects pad on the JBL.
Test Results
for pictures & test results
for pictures & test results
for pictures & test results
