Peri Duo iPhone case review

PERI Duo: The Hardcore Music Lover’s Multi-Function iPhone Case

Gadgets Reviews
Peri Duo iPhone case review
PERI Duo case for iPhone 6/6s with built-in wireless speaker and battery (Image copyright PERI)

My 16-year-old daughter has been helping me out with a new device that’s aimed squarely at her demographic. That would be young, music-loving, social, iPhone-toting individuals who frequently tax the limit of their smartphone’s battery. The PERI Duo takes multifunction iPhone cases to a whole new level, with basic protection, a built-in battery, plus a built-in wireless speaker. It’s a heck of a thing, but does it hit the mark or is this a Frankenstein gadget that’s a big, lumpy mishmash of cobbled-together functionality? And is it worth the $189.99 asking price? Read on to find out…

Retro Boom Box Look

PERI nailed the look of the Duo case. Available in several color options (black, red, white, and a funky Rhymesayers print) it looks like an old school boombox—miniaturized. The back of the case is dominated by a pair of round, mesh-covered speaker grills. Above one are four control buttons with LED indicators.

The one miss? You can’t set the PERI Duo on its edge (with speakers facing forward). You’ll need to prop it up or set it screen-down with the speakers facing up.

Peri Duo speaker case review
PERI Duo is probably the coolest-looking iPhone case I’ve seen to date, and obviously the best-sounding one (Photo by Brad Moon)

Ease of Installation

This couldn’t be easier. Pop the iPhone in, then a slider connects to the Lightning port. Done. And it’s just as easy to remove the iPhone.

Bluetooth and Wi-Fi Speaker

The big feature on the PERI Duo is its ability to seriously upgrade an iPhone’s built-in speaker, even taking the place of a portable wireless speaker.

Behind the speaker grills are one 40mm neodymium driver and a passive radiator for extra bass punch. Amplification power is 4-watts. The combination is able to pump out some decent audio, leagues beyond what the iPhone itself is capable of and rivaling a small, standalone speaker. You won’t be deejaying parties with the PERI Duo, but it’s well-suited to playing music in a bedroom or dorm room, and it’s perfect for playing the latest track for your friends while sitting around, wherever.

You have multiple music playback options: direct connection, Bluetooth, and Wi-Fi. All three methods are available when the iPhone is installed, and both wireless options can be used without the iPhone physically in the case—literally using the PERI Duo as a standalone wireless speaker. There is one-button quick playback of a favorite Spotify playlist for fans of that streaming service, and in the case where multiple people have PERI Duo cases, up to 64 can be linked together wirelessly for synchronized audio.

Battery Boost

All that speaker power requires—well, power. The case has its own 2900 mAh battery (charged via micro USB) to keep the music playing. With music at a reasonable volume, you can expect up to 10 hours of playback through the direct (Lightning) connection, up to 15 hours using Wi-Fi, and as much as 20 hours when streaming via Bluetooth.

That battery can also be used to top up the iPhone’s battery. The iPhone 6 has an 1810 mAh battery, so you can get a full charge and then some—assuming you haven’t drained the PERI Duo’s battery on music playback. Instead of charging her iPhone daily (and sometimes running out of battery by the time school was over), my daughter could get away with charging the Duo (which also charges the iPhone on a pass-through connection) every few days.

Two Elephants in the Room

When it comes to deciding whether the PERI Duo is the iPhone case for you or a music lover in your family, there are two big factors that need to considered.

The first is cost. Let’s face it, $189.99 is a lot for an iPhone case (although it’s currently available for $149.99 on Amazon, which does take some of the sting out). However, the cost needs to be weighed against the fact that the PERI Duo is a battery case and also arguably eliminates the need to buy a portable Bluetooth speaker. So if you need all three—case, backup battery, and small speaker—it’s pretty reasonable.

Peri duo case for iPhone 6 review
The downside to strapping your iPhone into a boom box is bulk (Photo by Brad Moon)

The second factor is bulk, and this is the one that saw my daughter eventually relegate the case to occasional use instead of a daily iPhone case. While it’s an impressive feat of engineering to incorporate an amp, drivers, and wireless radios into a case that measures 2.75 x 6.06 x 0.78-inches and weighs 5.4oz, the reality is the PERI Duo turns the sleek iPhone into a fairly bulky device. It makes an iPhone 6 nearly three times thicker and more than doubles its weight. Like many protective cases, you’ll also need to use a headphone jack extender (PERI includes one in the box).

Finally, there’s the current iPhone model availability: iPhone 6 and iPhone 6s only, so if you have an iPhone 7 you’re out of luck for now.


Hardcore music lovers—people who like to have their tunes available to play out loud at a moment’s notice—will love the PERI Duo case. It absolutely blows away what their iPhone’s built-in speaker is capable of and eliminates the need to lug a portable speaker around. They’ll like it even more if they tend to push their iPhone’s battery to the limit. Frankly, this is the case I would have saved up for had there been smartphones when I was younger. Gadget lovers will also appreciate the retro design and technical features. Ultimately, it’s going to come down to budget and a willingness to transform the iPhone into a noticeably bulkier device.

Update: I heard from PERI after CES 2017 and they’ve announced the DUO Slim. This speaker case offers many of the same features of the PERI Duo, minus the Wi-Fi (it still has Bluetooth) and a slightly lower capacity 2500mAH battery. However, in exchange for these minor trade-offs, it’s much thinner and the retail price is considerably less at $129 (discounted further on Kickstarter). The Duo Slim will support the iPhone 7 series.

Disclosure: PERI provided a Duo case for review purposes.

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