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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-02 · 8 min read · Independent comparison
• DESOBRY's biggest strength: it is a five-mode stereo box (CD / Bluetooth / USB / FM / AUX) with dual speakers, a rechargeable battery, a remote and a color TFT screen — a lot of playback paths in one portable unit.
• DESOBRY's biggest trade-off: it is a boombox, not wearable audio. Nothing about it is designed to go on your head, and in a car the only connection route is the 3.5mm AUX cable — no Bluetooth link to the car stereo.
• Monster Open Free AC100's biggest strength: genuine wireless freedom — Bluetooth 5.3, 16mm dynamic drivers, earhooks, 30 hours of total playtime and AI noise-canceling with dual mics, all in a white open-ear design.
• Monster Open Free AC100's biggest trade-off: it only does one thing. There is no CD slot, no radio, no USB playback, no AUX path — it is purely a wireless listening device, and each single charge tops out at 6 hours before it needs the case.
• Pick DESOBRY if your music still lives on discs, you want a speaker for a room, a desk or a car, and you like being able to hand the remote to someone else.
• Pick Monster Open Free AC100 if you want headphones that stay off your ear canal, keep you aware of traffic and conversation, and pair wirelessly to a phone, tablet or laptop.
The DESOBRY is the more unusual product of the two, because it refuses to pick a lane. It is a portable CD player with a rechargeable battery, but it is also a Bluetooth speaker in both directions: it can receive audio from a phone, laptop or tablet, and it can transmit, so the thing you are listening to can be pushed out wirelessly. That transmit/receive pairing is the detail that separates it from a plain disc player. Around the house it means you can use it as a small stereo speaker one evening and as a CD deck the next.
Then there is the mode list: CD, Bluetooth, USB, FM and AUX. FM tuning runs across 76MHz–108MHz, so news and music stations are on the table whether you are at home or sitting in a car. USB playback accepts drives formatted FAT32 up to 32GB, which is a tidy way to carry a whole library without carrying discs. Format support covers CD, CD-R, CD-RW, HDCD and MP3, with four play modes and five EQ presets — POP, JAZZ, ROCK, CLASS and FLAT — so you can shift the tone depending on what you are playing. Dual speakers handle the output, and volume can be adjusted either on the unit or from the included remote.
Who should buy it: anyone with a shelf of CDs who also wants a rechargeable speaker, FM radio and USB playback in one box, and anyone who wants a remote so they can control playback from across the room or the car. Who should skip it: anyone who wants headphones. The DESOBRY has a 3.5mm headphone jack and RCA connectivity, but its whole reason for existing is loudspeaker playback — if your goal is private listening on the move, this is the wrong shape of product. Also skip it if you expect to pair it to your car's Bluetooth system, because the car route is AUX only.
Monster Open Free AC100: Who It's For
The Monster Open Free AC100 is the opposite kind of product: small, wearable, wireless and built around one job — putting stereo sound near your ears without sealing them. The open-ear, air-conduction design sits outside the ear canal rather than inside it, which is the entire point. Nothing is pushed into the ear, so there is no soreness from long sessions, and because your ear canal stays open, ambient sound keeps coming in. That is why the spec sheet leans so hard on awareness: you hear traffic, announcements and the person next to you while your music plays.
The audio hardware is a pair of 16mm dynamic drivers, which is a large driver for this category and is what Monster is pointing at when it talks about an expansive soundstage, deep bass and crisp highs. For calls and voice, there are dual microphones with AI noise-canceling that monitors surrounding sound and produces an opposing signal to cut background noise — useful in a café, an open office or on a noisy street.
Wireless is Bluetooth 5.3. In practice that means a faster, more stable connection than older generations, and a simple pairing flow: the two earbuds link to each other automatically, then you pick "Monster Open Free AC100" from your device's Bluetooth list. It pairs with phones, tablets and laptops alike. Battery is stated as 30 hours total, with up to 6 hours per individual use — so the total figure assumes recharging in between, and the 6-hour number is what a single continuous session looks like.
Physically it is white, open-ear in placement and open-ear in shape, with earhooks to hold it in place — the design signals running, walking and gym use. It is listed as waterproof earbuds for running, and it ships with a user manual and a 1-year manufacturer warranty.
Side-by-Side: Which Should You Choose?
• Best for physical media → DESOBRY. CD, CD-R, CD-RW, HDCD and MP3 disc playback, plus USB drives up to 32GB.
• Best for wireless freedom → Monster Open Free AC100. Bluetooth 5.3 with automatic earbud pairing and no cables at all.
• Best for listening around other people → Monster Open Free AC100. Open-ear design keeps you aware of your surroundings; the DESOBRY fires sound out of dual speakers for everyone in the room.
• Best for a room, desk or car → DESOBRY. FM radio from 76MHz–108MHz, AUX in, and an AUX cable in the box for connecting to a car's system.
• Best for long sessions → Monster Open Free AC100. Up to 6 hours per use and 30 hours total, with an earhook fit that avoids ear-canal soreness.
• Best for calls in noisy places → Monster Open Free AC100. Dual microphones with AI noise-canceling.
• Best for hands-off control → DESOBRY. The included remote handles mode switching, radio, volume and more from a distance.
• Best for portability on your body → Monster Open Free AC100. It is worn, not carried; the DESOBRY is a 0.25 kg box you set down somewhere.
In my opinion these two only overlap on one word — Bluetooth — and that word means something different in each. The DESOBRY is a Bluetooth stereo system: a rechargeable five-mode boombox with dual speakers, FM radio, USB, a remote and a color screen, and if you still own CDs or want a speaker that lives in a kitchen, a study or a car, I would buy the DESOBRY. The Monster Open Free AC100 is Bluetooth headphones done for open-ear comfort and awareness, and if your listening happens while moving — running, walking, commuting — I would buy the Monster Open Free AC100. Decide which of those two lives is yours, and the choice makes itself.
how to connect bluetooth wireless headphones
On the Monster Open Free AC100, the two earbuds pair with each other automatically once powered on, then you open Bluetooth on your phone, tablet or laptop and select "Monster Open Free AC100" from the list. No app or complex setup is described — it is a straight Bluetooth 5.3 pairing.
how to pair bluetooth wireless headphones
Pairing is a two-step habit: get the earbuds into their pairing state, then choose them on the source device. With the AC100 the steps run in that order — automatic earbud-to-earbud linking first, then selection on your device's Bluetooth menu — which is why Monster describes the process as avoiding complicated operations.
how to bluetooth wireless headphones
If what you actually want is to send audio to a speaker from something else, that is what the DESOBRY's Bluetooth receive mode is for: it accepts audio from a phone, laptop or tablet and plays it through its dual speakers. The AC100 works the other direction — it is the thing you listen through.
Yes — I deliberately do not quote prices here, because they move. Use the "Check latest price on Amazon" button on this page for both the DESOBRY and the Monster Open Free AC100 before you commit, and compare them against what each one actually does for you.
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