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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want a shared TV-listening setup that lets two people watch together at their own volume without touching the TV speakers, choose SIMOLIO 737D; if you need a portable HiFi source that plays CDs, doubles as a USB DAC, and drives serious over-ear headphones, choose FiiO DM15.
• SIMOLIO 737D — biggest strength: two pre-paired over-ear headphones with independent volume control, a bypass feature that keeps your soundbar or AV receiver in the mix, and a charging dock that doubles as a headphone stand.
• SIMOLIO 737D — biggest trade-off: it's a TV-first product. There's no active noise cancellation, no L/R balance control, and direct Bluetooth pairing to a TV can limit dual streaming and add latency, so the transmitter is the intended path.
• FiiO DM15 — biggest strength: a genuinely portable CD player with a self-developed fully differential 24-bit R2R DAC, up to 1150mW per channel balanced output, and aptX Adaptive Bluetooth transmission from CD or USB input.
• FiiO DM15 — biggest trade-off: it has no headphone jack in the literal sense of a passive analog input, it plays physical discs one at a time, and its supported audio format listing is narrow (MP3) — this is a niche audiophile device, not a household one.
• Who each is for: SIMOLIO 737D is for couples, families, and hard-of-hearing viewers who want TV audio at individual volumes. FiiO DM15 is for the listener who still loves CDs and wants a compact HiFi rig for headphones.
The 737D Plus is built around one problem: two people, one TV, two different ideas of how loud it should be. You get two pre-paired wireless headphones in the box, and each pair has its own volume control. Turn yours up, your partner keeps theirs where they like it — neither of you touches the TV remote. For couples where one person has mild hearing loss and the other doesn't, that alone is the whole pitch.
The feature I find most practical is the bypass function. The headphones work together with your existing soundbar or AV receiver instead of hijacking the audio output. So the room can still hear the TV through the soundbar at a normal level while you listen through the headphones at yours. That's a real difference from a lot of TV headphone kits, which force the TV speakers silent. Setup is accordingly simple: plug the transmitter into your TV's audio output, power both on, done — no pairing dance. In TV mode you get synced audio and video with a stated 25 ms latency, up to a 164 ft (50 m) open-air range, and 20 hours of playback per charge. Three EQ modes (clear dialogue, standard, cinema) let you push dialogue forward when a show's mix is muddy.
Comfort details matter for long sessions: protein earmuffs, a retractable soft-padded headband, and over-ear PU/fabric/silicone construction. The transmitter doubles as a charging dock, and you can also charge by cable.
Who should skip it? Anyone hoping for noise cancellation — there is none. Anyone who wants separate left/right balance control — SIMOLIO points those buyers to a different model. And if you plan to pair the headphones directly to a smart TV over Bluetooth rather than through the transmitter, expect possible latency and no dual streaming. Also note the optical-connection quirk: if you hear nothing over optical, your source may be outputting Dolby or 5.1, and switching it to Stereo PCM usually fixes it.
The DM15 R2R is a different animal entirely. It's a portable stereo CD player that also works as a HiFi USB DAC and a Bluetooth transmitter — and it's aimed at someone who cares about how digital audio is converted, not just whether it plays. The headline is FiiO's self-developed, fully differential complementary 24-bit R2R resistor array DAC, built from 192 resistors at 0.1% precision with low temperature drift. In plain terms: R2R designs are associated with a warmer, smoother, more "analog" character than typical delta-sigma chips, and FiiO is explicitly chasing that classic portable-CD-player feel.
The output stage is the other story. FiiO rates it at up to 1150mW per channel balanced, which is a lot for a device this size — enough to drive demanding over-ear headphones without an external amp. Compared with the previous generation, the body is 2 mm thinner while output went up, so it stays genuinely pocketable.
Wireless is handled by Qualcomm's QCC3095 chipset with aptX, aptX HD, aptX Adaptive, and SBC. Both the CD input and the USB input can be transmitted over Bluetooth, and there's a visual interface for pairing and switching devices. In USB DAC mode it handles up to 384kHz/32-bit PCM and DSD256. For tweaking, you get 3-stage BASS boost plus 8 EQ presets — 24 total combinations — including a RETRO mode tuned for a vintage flavor.
Who should skip it? If you mostly stream, this is overkill; the value is in disc playback and DAC quality. It plays one disc at a time, it lists no headphones jack on the connectivity sheet (you're relying on its outputs and wireless), and its supported audio format field reads MP3 — so don't assume broad codec support beyond what's documented. If your goal is family TV audio, this isn't the tool.
• Best for watching TV with two people at different volumes → SIMOLIO 737D. Two headphones, two independent volume controls.
• Best for keeping your soundbar in the loop → SIMOLIO 737D. The bypass feature lets headphones and external audio run simultaneously.
• Best for long, comfortable viewing sessions → SIMOLIO 737D. 20 hours per charge, over-ear padding, retractable headband.
• Best for large-room freedom → SIMOLIO 737D. Up to 164 ft open-air wireless range.
• Best for CD collectors → FiiO DM15. It's a disc player first, with a serious DAC behind it.
• Best for driving power-hungry headphones → FiiO DM15. Up to 1150mW per channel balanced.
• Best for a desktop or laptop HiFi DAC → FiiO DM15. USB DAC up to 384kHz/32-bit and DSD256.
• Best for wireless freedom from a physical source → FiiO DM15. CD and USB input both transmit over aptX Adaptive Bluetooth.
• Best for sound tweaking → FiiO DM15. 3-stage BASS plus 8 EQ presets, with a dedicated RETRO mode.
• Best for a household shared device → SIMOLIO 737D. It ships as a complete kit: transmitter/charging dock, two headphones, power adapter, audio cable kit, USB-C cable, and guides.
In my opinion, these two barely compete — they solve opposite problems, so the "better" one is simply the one that matches your room. If your household argues about TV volume, or someone struggles to follow dialogue, I'd buy the SIMOLIO 737D; the dual headphones, independent volume, and soundbar bypass are exactly what that situation needs, and nothing on the FiiO side addresses it. If instead you want one compact box that plays your CDs, converts them beautifully, and can drive real headphones, I'd buy the FiiO DM15. My honest split: for most homes, the SIMOLIO is the more useful purchase.
Yes, in my opinion. The 737D is designed for TV audio — two headphones, independent volume control, three EQ modes, and a transmitter/charging dock. The DM15 has no TV-focused features at all.
Yes. FiiO documents USB DAC mode supporting up to 384kHz/32-bit PCM and DSD256, and both CD and USB input can also be sent out over Bluetooth.
Yes — switch the headphones to Bluetooth mode and pair them directly with any Bluetooth device, including phones and tablets. Just remember TV mode with the transmitter is the better route for low-latency TV audio.
They sit in different product categories, so pricing moves around and I won't guess at numbers. Check the current price on Amazon before deciding — the button on this page will show it.
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