Buy a set of wireless headphones with LDAC or aptX support, plug them into an iPhone, and you will never hear what you paid for. iOS talks to Bluetooth headphones in AAC and nothing else, so every high resolution codec your headphones are capable of sits there unused. The fix is a dongle in the USB-C port that takes the radio off the phone completely: it handles the pairing, it picks the codec, and the phone just feeds it audio. We have five worth buying, from £42.99 to £99, and one of them has walked away with a Wavemaker.

Two things to settle before you spend anything. If you listen on AirPods, none of this will help you, because AirPods are AAC only at the other end as well, and no transmitter can invent a codec your headphones do not have. If you are still choosing those, our guide to the best wireless earbuds for serious listeners is the place to start. You also need USB-C, which means an iPhone 15 or newer, or any recent iPad. Lightning iPhones can be coaxed into working with an adapter, but it is a fiddle we would not build a purchase around.

Questyle has done the one thing nobody else in this category bothered with: it paid Apple. The QCC Dongle Pro2 is MFi certified, meaning Apple has tested it and signed it off for iOS. In practice that is the difference between plugging something in and plugging something in while hoping, which counts for a lot when compatibility is the entire reason you are buying one of these.

The codec list is the longest of the five. Bluetooth 6.1 carries aptX Lossless, LDAC, LHDC, aptX Adaptive and aptX HD, plus LE Audio and its LC3 codec, so whatever your headphones speak, this will find it. Auracast is in there too, which lets one source feed several sets of headphones at once, although your headphones need to support it before that does anything for you.

It is also the smallest thing here by a wide margin, 2.2g and 25mm long, in vacuum plated PC and ABS. Latency falls to 48ms on aptX Adaptive and 20ms in LE Audio low latency mode, the figure that matters if you watch anything on the phone.

The catch is not finding one, it is what you pay for it. Questyle lists the Pro2 at $99 and is selling direct at $75 as this goes out. Amazon has it in all three regions, but the UK and German buy boxes belong to marketplace sellers rather than Questyle, which pushes them to around £106 and up here and nearer €170 in Germany. They will reach you quicker. They will also cost you noticeably more, so look at the direct price before you take the convenient option.

Your iPhone has one port, and a transmitter takes it. That is the end of charging, which on a long flight or a long day out is a genuine problem rather than a theoretical one. The FiiO Air Link deals with it the obvious way, by putting a second USB-C socket on the body that accepts a charging cable while the dongle is running.

Everything else about it is quietly sensible. Qualcomm's QCC5181 chip runs Bluetooth 6.0 and the whole aptX family including Lossless, plus LDAC, and the Air Link sorts out the priority itself: it reaches for aptX Lossless first, drops to LDAC if the headphones cannot manage it, and works down from there. You never open a settings menu.

Range runs past 50 metres, which is far more than you need from a phone in your own pocket, and latency sits around 50ms. At 5g it is light enough to forget, though at 34.5mm it is the longest of these five, and with a charging cable attached you do end up with a small stack hanging off the bottom of the phone.

At £42.99 it is also the cheapest thing in this guide that does everything.

Noble calls the Sceptre a codec and RF enhancer, and the second half of that description is the more interesting one. A phone's Bluetooth antenna is buried inside a body made of metal and glass, usually with a hand wrapped round it, which is why wireless audio stutters the moment you put the phone in a back pocket. A dongle poking out of the bottom has a clear path to the air, so the link holds together in exactly the conditions where phone Bluetooth gives up.

Noble Audio has built it on the same Qualcomm QCC5181 as the FiiO, running Bluetooth 5.4, with LDAC and aptX Adaptive alongside AAC and SBC. Its launch materials describe a charge through design here as well, so the phone is not left stranded on a single port.

What it does not have is aptX Lossless, and that is the thing to weigh, because at £64.99 it costs half as much again as the Air Link, which does. Noble's pricing is at least straight across borders, £64.99 in the UK, $69.99 in the US and €69.99 in Europe, which is rarer than it should be and saves you doing the sums.

Buy this one for the strength of the connection rather than the length of the codec list.

Most of these dongles are a radio and nothing else. The iFi UP Play Max is the one that processes the signal on the way past, through K2 Technology, a licensed JVCKENWOOD process that iFi describes as restoring harmonic content lost when music was digitised in the first place. You can switch it off if you would rather hear the file untouched, which is the right way round for a feature like this.

Bluetooth 5.4 handles aptX Lossless, LDAC, aptX Adaptive, aptX HD and the rest. There is a microphone on board with noise and echo suppression, so calls still work, and dual pairing feeds two sets of headphones from one phone. Auracast is promised in a firmware update that has not landed yet.

Three caveats, and together they are why this sits here rather than higher up. Codec choice, the K2 toggle and the low latency mode all live inside iFi's Nexis app, so this is not really plug and play: you are installing something before you can reach most of what you paid for. Dual pairing drops the connection to SBC, so the moment you share, the codec advantage disappears. And iFi quotes range at 10 metres or more, against the 50 metres FiiO claims, which is plenty for a phone in a pocket but no good for leaving it in another room.

Everything else in this guide was made by a company that makes dongles. The ATX001 was built by one that makes earphones, as the wireless partner to Acoustune's own modular IEMs, and the thinking shows in the details rather than the headline numbers. The codec list is the full Qualcomm set, aptX, aptX HD, aptX Adaptive and aptX Lossless, with LDAC, AAC and SBC alongside it, running on the same QCC5181 as the two FiiO units over Bluetooth 5.4. Codec choice and firmware updates go through Acoustune's ANIMA Studio app rather than a button you press and hope about.

There is a second USB-C port on the underside for a charging cable, so the phone is not stuck on a single socket while you listen. At 4g it is nothing in the hand, though at 42.5mm it is the longest of these five, a little more than the Air Link. The box also holds a USB-A to USB-C adapter, which is the detail worth noting: it means the same dongle serves an older laptop or a desktop machine without a second purchase, and none of the others bother.

Two things to weigh. Acoustune quotes maximum transmission distance at about 10 metres, the shortest claim here by a wide margin and a fifth of what FiiO puts on the Air Link. That is fine for a phone in a pocket and no good for leaving it on a kitchen worktop. The other is where you buy it: nobody lists it on Amazon in Britain, America or Germany, so it means going direct, where Acoustune prices in your own currency at £58, €67.95 or $75. That is also the cheapest route by a distance, because the specialist importers who carry it are asking $99.99.

The Questyle QCC Dongle Pro2 takes it, and the Wavemaker with it: the longest codec list of the five, Bluetooth 6.1, and the only Apple MFi certification in the category, which is precisely what you want when compatibility is the whole reason for the purchase. If £99 is more than you fancy handing over for a dongle, the FiiO Air Link does nearly all of it for £42.99 and throws in a charging port the Questyle does not have.

Still building the rest of the chain? We have guides to the best digital audio players worth buying right now if you would rather sidestep Bluetooth altogether, the best wired IEMs for serious listeners for the same reason, and the best DJ headphones for every budget if you are buying for the booth.

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