If you’re looking for a speaker for a party, choose one that can get loud enough to fill a large room or crowded outdoor spaces. These are often large and heavy since they reproduce deeper bass than smaller models. Many also feature RGB lights and inputs for microphones and instruments. That brings us to the Sony ULT Tower 9AC, which we’ve been using for a week. In a house with a 14-year-old around, the party never stops. Here’s how it went.

Comparing it with ULT Tower 9

Walk into a shop and you might be unsure whether to buy the Sony ULT Tower 9 or the ULT Tower 9AC. There’s no difference in looks — the speakers are identical. What?! The only difference is that the 9AC, as the name suggests, runs solely on electricity, while the Tower 9 has a battery.

If you’re undecided, ask yourself: do you really need a battery? Otherwise, both share the same drivers, Bluetooth version, stereo pairing and Party Connect. Each has wheels, mic holders and a sound booster.

Link up to 100 compatible speakers to synchronise music and lighting through Party Connect

Because the Tower 9 includes a battery, it’s slightly heavier. Yet if you love party speakers, chances are you won’t stray far from a power socket. These are mostly used indoors or by the poolside, where a plug point is usually within reach — unless you plan to haul this 28kg unit to a picnic.

The ULT Tower 9AC is the better pick because it’s always plugged in, delivering consistent output. The bass has plenty of thump, and at maximum volume, it gets seriously loud.

Without a built-in battery, you can push the volume all the way up. Otherwise, you’d need to stick to about 35–40 per cent volume to get 25 hours from a battery-powered version, and that too with the lights off. Realistically, playing at 60 per cent with ULT and lights on gives under 10 hours — another reason to go for the AC model.

All those lights

Moving the speaker is easy thanks to its wheels, which roll smoothly over carpets and wooden floors. Be careful while shifting it — the mostly plastic body can scratch easily.

The speaker’s lighting gives it a striking presence in your living room. Its floor lights have a wide glow, best used indoors and at night.

Sony’s app lets you control and customise the lights extensively. It’s a neat touch, though lights do drain battery life on portable versions. That’s where the AC model shines — it’s always plugged in.

Sound quality

There are several ports — you can connect a microphone for karaoke or plug in a guitar, though two mic inputs would’ve been better. When singing along, you can add echo at various levels and even adjust pitch — key control being a true party-animal feature.

Using Sony’s microphones makes connectivity smoother. Mic holders on the speaker help during karaoke. On the back, there’s a USB-A port (a USB-C would’ve been nicer). An audio jack allows wired use, and the optical port lets it double as a soundbar. During a sports telecast, it easily outperforms mid-range soundbars.

A few of the ports on the device (left) and larger castors make this speaker easy to move

It connects to two devices simultaneously and supports SBC, AAC and LDAC — Sony’s high-res codec. Note that LDAC works only on Android, while iPhones top out at AAC.

The setup includes a woofer with front exhaust ports, dual front-firing mid-range drivers and four tweeters — two at the back, two up front. Sound can be adjusted via Sony’s app, which offers a custom EQ.

There are two ULT modes: one enhances bass, the other boosts sound pressure, sharpening mids and highs. ULT1 works best indoors.

The bass feels powerful yet controlled, never muddying vocals — Dua Lipa’s Radical Optimism sounds crisp. There’s excellent balance and instrument separation, even better than comparable JBL models. Classical pieces like Tchaikovsky’s Swan Lake also sound refined and layered.

Make the call

For a 50-person party, this is the speaker to have — it even strays into commercial territory. Ideal for small DJ gigs or restaurants, it benefits from always being plugged in. With 2025 nearing its close, you might already be planning your next celebration. The Sony ULT Tower 9AC will make sure the party never misses a beat.

At a glance

Device: Sony ULT Tower 9AC

Price: ₹79,990

High notes

Powerful, room-filling sound

Deep, thumping bass

Always-on power for consistent performance

Customisable lighting effects

Durable wheels for easy movement

Strong karaoke features with echo and key control

High-res LDAC support

Muffled notes

Plastic body prone to scratches if you are not careful

Lacks USB-C port