AIAIAI Unit-4 review: Unique wireless portable studio monitors

I’ve been using the studio monitors for a couple of months now. And initially, I wasn’t sure what to make of them. They’re solid studio monitors with 4-inch woofers and 1-inch silk tweeters. They sound good and look good. But the pitch — the reason these things cost for a pair — is that they’re wireless. And not, “they’re studio monitors that also happen to have Bluetooth” wireless, though they have that as well. They include AIAIAI’s low-latency 2.4Ghz wireless tech that made its debut on the a couple of years back. Plus they have sizable batteries, allowing them to run for up to 20 hours without any cables at all.

I was skeptical of the Studio Wireless+, but was eventually won over by the surprising convenience of not being tethered to my audio interface by a 3-meter long coiled cable. The have a somewhat tougher case to make, though. The cables that keep my current PreSonus monitors tethered to my desk don’t get in the way. I don’t have to unplug them to put on my guitar and I don’t trip over them while grabbing a synth from the shelf. Instead, the Unit-4 are meant to solve a very specific problem: needing studio quality monitors when you’re not in your studio.

As you might imagine, this is not a thing I find myself needing terribly often. I’m sure that someone out there, likely professional musicians who spend significant time on the road, would immediately see the appeal. But for a hobbyist like me, finding a use case is harder.

Before we get too deep into the “why,” let’s talk a little bit about the “what.” Until now AIAIAI has focused exclusively on headphones. A more conservative company might have simply made some bog-standard studio monitors and called it a day. But today you can get bog-standard studio monitors, and pretty decent ones at that, for not much money. So rather than just add more noise to an already saturated market, AIAIAI looked to see what it could do that would be unique.

The somewhat surprising answer it got from some artists was wireless, battery-powered monitors. So it took the low-latency W+ Link technology it had developed for Studio Wireless+ and adapted it for use in a pair of 4-inch studio monitors. Where Bluetooth latency can be all over the map, ranging from around 40ms under ideal conditions with the latest hardware, to well over 100ms, W+ Link is a consistent 16ms. It’s not zero latency, but it’s close enough for a quick recording session or a casual jam.

Because of their size you’re not gonna get a ton of bass out of them. You get a surprising amount more low end just by jumping up to 5-inch woofers. But, it’s not like the Unit-4 lack oomph. They’ve got a decent amount of punch and a reasonably flat frequency response. That said, as with the Studio Wireless+, I find their tone a touch on the dark side.

There is an app for iOS and Android, though, where you can tune the EQ to your liking. I personally scooped the mids and cut the sub bass just a smidge to help brighten up the sound ever so slightly and keep things from getting muddy in my small attic studio. But there are also useful presets in there depending on where you are and what orientation the speakers are in, whether that’s horizontal on your desktop or on a picnic blanket in a park.

While it’s purely subjective and of little practical value, the Unit-4 look great in any orientation or setting. They’re much better looking than most studio monitors. They’re sleek, black and have a stylish metal speaker grill that attaches firmly with the help of a few magnets. A ring of white light glows around the woofer when they’re powered on too. Like I said, it makes no functional difference, but they’re certainly a visual upgrade from my PreSonus Eris E5s.

There are a few design choices that I can quibble with, however, even if I understand the reasoning (usually to shave size and weight). First off, the Unit-4 lack XLR hookups. This isn’t unheard of on portable studio monitors, and they do have balanced TRS connections, but combo XLR / TRS jacks are pretty ubiquitous at this point and wouldn’t have required much more room.

The power bricks for each speaker are also enormous. Obviously, putting those components inside the speaker, along with their sizable 77Wh batteries, would have dramatically increased their size and weight. But it seems odd that, what I believe are, the largest power bricks in my home currently belong to the Unit-4, while none of the other studio monitors or speakers I own have external power supplies at all, just standard AC cables. They weigh more than a pound each, which means that, despite AIAIAI bragging that the Unit-4 only tip the scales at 2.5kg (or about 5.5 pounds), if you were to hit the road with two monitors and the chargers for each you’d be looking at a total weight of close to 14 pounds.

That’s hardly unreasonable if your definition of portable is simply that you can move them from place to place — nobody is taking the Unit-4 with them on a whim on the off chance that they might need a studio monitor. Still, I will say that I think AIAIAI should include the carrying case if they’re pitching the portability factor, rather than it being a $70 add-on.

My biggest issue, though, was the decision to remove the battery from the transmitter. The X01 Transmitter that comes with the Studio Wireless+ has a built-in battery. The X02 Transmitter that is packaged with the Unit-4 does not. The perk of this is that, when used as a USB-C audio dongle with a laptop, it’s nice and discrete. The downside is that if you use the minijack output you need to provide your own power, preferably via a powerbank, rather than an AC adapter to minimize opportunity for interference or ground loops.

Part of AIAIAI’s rationale for ditching the battery was that, well, batteries have a tendency to wear out. And this way, you don’t have to chuck the whole transmitter just because it won’t hold a charge anymore. But, the company has figured out how to make practically every part of the studio monitors (including the battery), so it seems like doing that for the transmitter shouldn’t have been too tough.

The lack of a battery is a non-issue if you’re primarily using the Unit-4 connected to a computer. But if you’re using a standalone piece of gear like an , connecting to a mixer for a jam session or out busking it in a park, the extra cable and external power bank become something else to forget at home and kind of undermine the whole “wireless” thing.

I know that seems like a lot of negatives all in a row, but these are honestly pretty minor complaints. And I think that, if you are one of the people who will get a lot of use out of the Unit-4, they probably won’t deter you. The audience here is undoubtedly smaller than with the Studio Wireless+, though. Where almost any bedroom producer could use a solid set of headphones that can be wired or wireless at a moment’s notice, bouncing from low-latency studio mode to Bluetooth at the flip of a switch. The list of musicians that need the same from their desktop studio monitors is probably pretty short.

I can imagine these being super handy on a tour bus but, I am not a touring musician. Instead where I found the wireless feature most useful was for dabbling with new musical toys from anywhere in my house. Rather than hide in my attic, I could bring one of the Unit-4s down into the living room (but not both), connect the transmitter and a powerbank to say, the and get some work done while also hanging out with my kids.

Just for the hell of it, I took the Unit-4 to a park to shoot some review photos. I can’t say that’s something I’d want to do terribly often. Lugging them through the park as I looked for a decent enough place to stage my shoot got tiresome pretty quickly. But, I did put their loudness to the test by cranking the speakers all the way with my SP-404 MKII set to top volume. Quite a lot of people stopped and stared at me with open hostility. They still sounded great, with no distortion and the audio remained clear and punchy even from a few dozen feet away. But, like with the Wireless Studio+, the W+ Link does introduce some noise that becomes noticeable as you approach the 75-percent mark on the volume.

They were handy as just regular ol’ Bluetooth speakers. While it’s been a touch too cold to throw parties in my backyard, I’ve set one of the Unit-4s up outside while I’ve raked the leaves. If I really wanted to make my neighbors hate me, I could turn the speakers all the way up and they’d even be audible over my trimmer and leaf blower.

And thanks to their giant batteries they’d easily be able to last through a few hours of yard work, a raucous BBQ, some late night cleanup and then some. AIAIAI claims over 20 hours of battery life, but doesn’t specify if that’s over Bluetooth or W+ Link. I did a battery rundown test where I left the Unit-4 connected over W+, occasionally playing music through them from Ableton Live and djay Pro with the volume set at 75 percent. The first speaker gave up the ghost after 17 hours and 46 minutes, and the second followed 11 minutes later. Considering the Studio Wireless+ last more than four times as long when on Bluetooth versus W+ Link, it’s safe to assume you’d be able to eke quite a bit more playtime out of the Unit-4 if you were using them strictly as Bluetooth speakers. Of course, if you did that you’d be missing out on the whole point of the Unit-4.

Even though they’re pricey, perhaps the ideal customer would be a busker. The Unit-4 can cover live performances with low enough latency to not be distracting, are reliable monitors for mixing in a studio, and also loud enough fill up an apartment or yard with tunes for a party. The only thing I wouldn’t want to rely on them for is DJing. While you could work around the latency by feeding both the cue and the live mix to a pair of headphones, it’s just a smidge too much if you really want to make sure your transitions are 100-percent on point.

One other thing worth noting is that the amount of latency you experience with the Unit-4 will vary depending on your source (USB-C vs ⅛” TRS) and even whether you’re on Windows or macOS. If you intend to use the Unit-4 with a Windows PC over USB-C you absolutely need to install the ASIO4ALL driver. Built-in Windows audio drivers have improved over the years, but they still can’t hold a candle to Apple’s Core Audio or Steinberg’s ASIO. To be clear, this isn’t an issue with the Unit-4, but with Windows. For the best results and the lowest latency, your best bet is still to use a dedicated Audio interface and to connect the X02 Transmitter to that using a TRS cable. Of course, that also means you’ll have to bring some way to power the transmitter, whether that’s a power bank or a USB-C power adapter.

If you are someone looking for a pair of portable studio monitors that let you (more or less) ditch the cables entirely, the are basically the only game in town. They’re stylish, natural sounding and have a completely unique set of features. But they’re definitely more of a niche product than the Studio Wireless+. While their price tag isn’t cheap, the flexibility and broader appeal make them an easier sell. The Unit-4 on the other hand are both quite expensive at $800, and trying to solve a very specific problem. At least I can say unequivocally, they solve that problem quite well.