We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-30 · 7 min read · Independent comparison
If you want to plug a Lightning iPhone straight into a car stereo, home receiver or any device with a round 3.5 mm jack, choose Seulliya Aux Cord; if you need actual earbuds in your ears with a mic for calls and a remote for volume and playback, choose SUPVOL iPhone.
• Seulliya Aux Cord — biggest strength: an Apple MFi certified chip plus a built-in DAC that pushes up to 24-bit/96 kHz audio over Lightning, so it talks to car stereos, speakers and headphones without the dreaded "accessory not supported" pop-up.
• Seulliya Aux Cord — biggest trade-off: it is a cable, not earbuds. There is no microphone, no remote, no drivers — you still need something on the other end to actually listen.
• SUPVOL iPhone — biggest strength: a complete 2-pack of in-ear earbuds with a built-in mic and inline volume/playback remote, so you can take calls and skip tracks without touching your phone.
• SUPVOL iPhone — biggest trade-off: the connection routine is fussy and unusual. The sheet describes turning on Bluetooth first, plugging in, then confirming a pairing window for a device named "Beats" — that is not the simple plug-and-play you expect from wired buds.
• Who each pick is for: Seulliya is for anyone routing iPhone audio into a car, speaker or hi-fi input. SUPVOL is for anyone who wants a spare pair of listening earbuds with a mic for calls.
The Seulliya Aux Cord is a one-job tool, and it does that job with decent parts. One end is Lightning, the other is a 3.5 mm male plug. Between them sits an MFi certified chip and a dedicated DAC, which is the piece that actually matters here — iPhones dropped the headphone jack, so any cable doing this conversion has to convert the digital signal properly. Seulliya claims support for up to 24-bit/96 kHz, and the spec sheet lists a 96 kHz frequency figure. In practice, that is more than enough for streaming music and navigation prompts through a car system.
Buy it if you drive an older car with an AUX port, own a home stereo or powered speaker with a 3.5 mm input, or want to feed a Lightning iPhone into a wired headphone setup. Skip it if your phone has USB-C — the sheet is explicit that this works only with Lightning devices, not USB-C or Micro-USB — or if you actually need earbuds, because there are none in the box.
SUPVOL iPhone: Who It's For
SUPVOL sells a pair of in-ear earbuds, two to a pack, in white plastic with rounded tips and a dynamic driver rated from 20 Hz to 20,000 Hz — the standard full-range window for consumer buds. There is a cable, an inline remote, and a microphone. The remote handles volume, playback control, and answering or ending calls, which is the whole point of this product: it turns your phone into a hands-free setup for calls and casual listening. The marketing language leans on "driving bass, tight mid, precision treble," which is the usual way brands describe a bass-forward in-ear tuning. Two pairs means you can leave one in a bag and one at a desk.
Here is the part I would want a buyer to read twice. The first bullet point on the sheet describes a Bluetooth pairing process: turn on Bluetooth, plug the earphone in, wait for a beep and a pop-up window, then tap connect — and if no window appears, open the Bluetooth list and find a device named "Beats." That is genuinely unusual for a product listed as a wired 3.5 mm jack with a cable. It tells me the connection setup is not a simple "plug in and go," and it may require a few extra taps the first time. When it reconnects later, the sheet says it does so automatically in 2–8 seconds.
Buy it if you want earbuds with a mic and inline controls, you like the idea of a two-pack, and you are fine with a one-time pairing dance. Skip it if you want zero setup friction or you are buying specifically to feed a car stereo — that is not what this is.
• Best for car stereo and AUX input → Seulliya Aux Cord. A Lightning-to-3.5 mm cable is exactly the part a car with an AUX jack needs.
• Best for taking calls → SUPVOL iPhone. The inline mic and remote are built for answering and ending calls without pulling out your phone.
• Best for hands-on listening → SUPVOL iPhone. Real drivers in your ears beat routing audio to a speaker you may not own.
• Best for signal quality claims → Seulliya Aux Cord. The MFi chip, DAC and 24-bit/96 kHz spec are the specific technical story here.
• Best for durability spec → Seulliya Aux Cord. A 15,000+ bend rating and TPE jacket are the only durability numbers either sheet gives.
• Best for travel and home use → Seulliya Aux Cord. Lightweight, short, and described as plug-and-play with no driver or external power needed.
• Best for keeping a backup pair around → SUPVOL iPhone. It ships as two, so one can live in a bag and one at home.
• Best if you hate setup steps → Seulliya Aux Cord. No pairing, no pop-up window, no device list.
In my opinion, the Seulliya Aux Cord is the safer buy for most people reading this comparison. The reason is not that it sounds better — I cannot claim that — but that its job is unambiguous and its design matches it: one Lightning end, one 3.5 mm end, a certified chip, a DAC, and a durability rating you can actually point at. The SUPVOL earbuds are a fine idea for call-taking, but that Bluetooth pairing routine described in its own feature list is the kind of quirk that makes a "wired" product feel like more work than it should be. If you specifically need earbuds with a mic, buy the SUPVOL. If you need to get iPhone audio into a car or a speaker, buy the Seulliya and stop overthinking it.
FAQ
how to use headphones for iphone
how to use wired headphones for iphone 15
The iPhone 15 moved to USB-C, so a Lightning cable will not fit it. The Seulliya sheet states plainly that its cable works only with Lightning devices and not with USB-C jacks, so it is the wrong part for an iPhone 15. You would need a USB-C-to-3.5 mm adapter instead, and the SUPVOL earbuds' 3.5 mm jack would need that same adapter to work.
how to use wired headphones for iphone
Plug the 3.5 mm plug into your headphones and the other end into the phone's port, then press play. On Lightning iPhones, an MFi certified cable like the Seulliya avoids the "accessory not supported" error that uncertified cables can trigger. On USB-C iPhones, use a USB-C adapter instead. Volume and playback are then controlled from the headphone cable remote, if it has one.
how to use wired headphones for iphone 16
Same situation as the iPhone 15: the iPhone 16 uses USB-C, so a Lightning cable is not compatible. Check your phone's port before buying anything — Seulliya's own product sheet warns buyers to verify this, because the cable is Lightning-only. For a USB-C iPhone, look for a USB-C-to-3.5 mm adapter and pair it with standard 3.5 mm headphones or earbuds like the SUPVOL set.
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