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Nov 24, 2023

The Best Bluetooth Kits for Every Car Stereo

After another round of testing, we now recommend the Besign BK01 Bluetooth Car Kit as our top pick for use with an aux-in jack. Our picks for the best FM transmitter and speakerphone models remain the

After another round of testing, we now recommend the Besign BK01 Bluetooth Car Kit as our top pick for use with an aux-in jack. Our picks for the best FM transmitter and speakerphone models remain the same.

If you want to stream music or listen to phone conversations through your car’s speakers, but your vehicle didn’t come with Bluetooth, an add-on Bluetooth kit is an inexpensive and effective solution. After testing dozens of models, we think the Besign BK01 Bluetooth Car Kit—which plugs into a car’s auxiliary-audio input (aux-in) jack—offers the best combination of sound quality, phone usability, and features. Below, we also include picks for vehicles that don’t have an aux-in jack, or for people who primarily use their phones for calls, rather than for music.

The Besign BK01 offers great sound quality for music and good sound quality for phone calls. It also lets you pair two phones and access your voice assistant with the click of an easy-to-find button.

Plugging into a car’s aux-in jack is the most reliable way to add Bluetooth to your car; it also produces the best-sounding results. The Besign BK01 Bluetooth Car Kit is the best overall aux-in kit we tested. In our tests, the Besign BK01 provided better sound quality for music than other kits. And it produced clearer-sounding voice audio, for more-intelligible phone calls, than many other models (though call quality isn’t as good as what you’d get with a dedicated speakerphone). As with some competitors, the BK01 will also let you connect two phones at once, and you can use the unit’s button to bring up Siri or Google Assistant for hands-free assistance.

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Although it works for voice calls, this FM transmitter is best suited to music streaming. You can see which station you’re tuned to and easily find a new one.

May be out of stock

If your car’s audio system doesn’t have an aux-in port, and you value music streaming over call quality, get the GOgroove FlexSmart X2 FM transmitter. It sends your phone’s audio to your stereo via FM radio, automatically connecting with your phone when you turn on the car. Although the GOgroove doesn’t have auto-scan (a feature that automatically tunes to the most open FM frequency in your area), we found its easy-to-turn tuning dial to be just as effective and easy to use as the auto-scan features on other units. No FM transmitters have great sound—especially when compared with an aux-in or native Bluetooth system—but the GOgroove sounds the best of the models we tested.

The Avantree CK11 offers the crispest, clearest phone quality at an affordable price, with one-button access to the voice-control features on your phone.

If you’ll be using your phone mainly for calls in the car, and you’re less concerned about listening to music or podcasts, the Avantree CK11 Wireless Handsfree Visor Car Kit produces clear, full, loud audio. We also like its easy-to-use volume knob, which doubles as a button to activate the built-in voice assistant on your phone, so you can dictate calls and more without taking your eyes off the road. In our testing, no other dedicated speakerphone offered a better combination of useful features, audio quality, convenience, and value.

The Besign BK01 offers great sound quality for music and good sound quality for phone calls. It also lets you pair two phones and access your voice assistant with the click of an easy-to-find button.

Although it works for voice calls, this FM transmitter is best suited to music streaming. You can see which station you’re tuned to and easily find a new one.

May be out of stock

The Avantree CK11 offers the crispest, clearest phone quality at an affordable price, with one-button access to the voice-control features on your phone.

If you’re driving an older car without built-in Bluetooth and you want to be able to jam out to your tunes and make calls over your car’s speakers without having to install a new car stereo, you have a few options. The three most common ways to accomplish this are with a Bluetooth receiver that plugs into a car’s auxiliary-audio (aux-in) port; with an FM transmitter that takes your phone’s Bluetooth-audio output and broadcasts it over FM radio waves that your car stereo can pick up; or with a dedicated Bluetooth speakerphone. The first two options let you listen to music or phone calls over your car’s speakers; the third option, a Bluetooth speakerphone, has its own built-in speakers and is designed with better call quality in mind.

None of these options is perfect, but each is portable, inexpensive (compared with the cost of replacing your car stereo), and relatively hassle-free. Depending on the system you choose, you may have to sacrifice your car’s 12 V accessory-power outlet (though some kits have pass-through USB ports for charging other devices) or regularly recharge the kit. And although sound quality varies across the types of add-on Bluetooth kits—the worst ones won’t sound as good as if you were connecting directly to a car stereo with built-in Bluetooth—one of these will more than suffice until you’re ready to upgrade your car or its stereo. To determine the best system for your needs, consider the following things:

Depending on the system you choose, you may have to sacrifice your car’s 12 V accessory-power outlet or regularly recharge your Bluetooth kit.

Though a Bluetooth car kit is the easiest and least expensive way to add Bluetooth to your car’s stereo, it isn’t the only option. If you also want a GPS navigator for turn-by-turn directions, many models—such as our top car-GPS pick—include Bluetooth connectivity for conducting hands-free calls. But you can’t stream music on them, and most cost considerably more than the kits we tested here, so we don’t recommend them as a general Bluetooth upgrade.

Alternatively, if you plan on keeping your car for at least a few more years, you could upgrade your car stereo; doing so will give you built-in Bluetooth connectivity along with—depending on the stereo—useful features such as satellite radio, Siri or Google Assistant integration, and even Apple CarPlay and Android Auto. This approach will cost more than a Bluetooth kit, but the resulting Bluetooth experience will be much more seamless, and you’ll get a great new car stereo in the process.

After researching 122 single-DIN, Bluetooth-equipped car stereos and testing nine, we think the Kenwood KMM-BT322U is the best for integrating with your phone.

The Pioneer AVH-W4500NEX is the best car stereo for people who want to add Apple CarPlay or Android Auto so they can use their smartphones in their vehicles.

We began by reading reviews for as many devices as we could find. CNET and PCMag are among the few places you can find reviews of Bluetooth car kits, and even then, the reviews on those sites tend to be years old. So we also read Amazon customer reviews, which are more recent and generally more numerous. Whether the product was an aux-in kit, an FM transmitter, or a speakerphone, the most important thing we looked for in reviews was ease of use and how close the product came to a native Bluetooth experience in your car. With that in mind, we set out to find the most promising candidates for each type of kit.

When deciding which models to test (and also during testing), we focused on the following criteria:

Our testing procedure has remained the same across several iterations of this guide. To evaluate the outgoing audio quality and sound clarity of phone calls, we left voicemails—one with the windows up and another with the windows down—while driving down the highway at about 55 mph. We distributed the audio files for those voicemail messages to a panel of Wirecutter editors and writers who ranked them and left comments on audio quality. For earlier versions of this guide, we conducted our tests in a 2013 Toyota Prius C, and for the latest two we used a 2006 Honda Civic.

For our latest update, we used a similar approach to test music quality. In order to avoid the subjective quirks of car stereos, we connected each aux-in kit to a Focusrite Scarlett 2i2, our top pick audio interface, and recorded a clip of a song streaming over Bluetooth from a phone. We then distributed those files—along with the original, uncompressed song clip as a blind control—to Wirecutter editors and writers, who ranked them on the sound quality.

The Besign BK01 offers great sound quality for music and good sound quality for phone calls. It also lets you pair two phones and access your voice assistant with the click of an easy-to-find button.

After testing 30 models in recent years, we’ve found that the Besign BK01 Bluetooth Car Kit provides the best combination of sound quality, phone usability, and features. It produced the best music quality, as well as good phone quality, giving it a distinct edge over the other models.

We checked the BK01’s music quality by playing audio through the same automotive sound system that a Wirecutter staffer has used for checking studio-recording mixes on a car stereo, and we found that the subtleties in the music shone through the way they were intended to—we didn’t hear any buzzing or distortion. Though we can’t guarantee that every vehicle will be free of interference, the BK01 comes with an optional ground-loop isolation cable that should cancel out any hum. We asked seven other staffers to rate the audio, too, and they found that the loss of quality was barely noticeable when comparing a song played over the BK01 to the original recording.

In terms of phone-call audio, the Besign’s outgoing-call quality was clear enough (inasmuch as any phone call ever is), although it was slightly tinnier and more distorted than with some other models, including the Roav by Anker Bluetooth Receiver and the Taotronics TT-BR04. The change in audio quality (and volume) when switching from music to phone could be jarring, but this was something we also experienced with every other model we tested. If you plan on using your Bluetooth car kit for phone calls more than for music, we recommend that you check out our dedicated speakerphone pick.

We found that the subtleties in the music shone through the way they were intended to.

The Besign BK01 is also easy to set up and use. When you first plug it into your car’s 12 V port, it automatically turns on in pairing mode; other models we tested require you to push a combination of buttons for pairing (this can also increase the chance that you’ll accidentally hit those buttons during use, setting you back to pairing mode while on the road). Once the Besign is paired with your phone, it will immediately reconnect each time you turn the car on. Many models promise this kind of automatic connection, but the Besign actually pulled it off consistently in our tests. The only drawback is that it’s mildly inconvenient if you share a car with another person—the BK01 reconnects to the last device it was connected to. If it connects to the wrong phone—or doesn’t connect, for some reason—you can disable the Bluetooth on the other phone, or re-pair by simply holding down the large center button until you hear a long tone (you might need to press the multifunction button one more time to actually reconnect; it can be a bit finicky).

The Besign’s small, unobtrusive design is sleek and modern, and this model comes with two magnetic mounts that allow you to easily remove the BK01 from the dash to protect against theft, or to use it in a different car. Two linked wires extend from the main disc: One connects to your car’s aux-in port and the other to the included 12 V USB charger. That charger also has an additional USB port, so you can charge your phone while listening to music, if needed (though we also like that you can disconnect the Besign from its included charger and use it with one that charges your phone more quickly). Like most of the other aux-in kits we tested, the Besign BK01 can also pair with two phones at once, making it great for road trips or alternating playlists with those of your friends.

Two clearly marked buttons on the front of the unit offer track-forward and track-back control—which may sound like an obvious feature, but it was one that we found lacking on several models, including the Roav by Anker Bluetooth Receiver and the Anker Soundsync A3352. The large multifunction button in the center of the Besign lets you pause and resume music or end a call, and it’s easy to find and press by feel, even when you’re keeping your eyes on the road. You can also hold this button down for two seconds to trigger Siri or Google Assistant, depending on your phone (the Anker models we tested couldn’t do this, either). Even though this is a nice convenience, it’s not entirely necessary, since many phones already offer hands-free digital assistants. Still, this can come in handy if you want to get directions or make outgoing calls using your phone’s voice assistant via the BK01. By contrast, the features on some competitive models are more limited; a few (including some FM transmitters that we tested) only let you accept incoming calls or call back the number that you last dialed or missed.

The Besign’s built-in echo- and noise-cancellation features are far from perfect, resulting in a slightly shrill sound on outgoing audio. That said, outgoing voice quality is still easy to understand, and it beats that of most of the other aux-in models we tested, except the Taotronics TT-BR04 and the Roav by Anker Bluetooth Receiver (which sounded better only when the noise-reduction features didn’t cut out our voice entirely). We thought the Besign’s other features made up for this slight dip in sound quality, especially since the incoming audio you hear during calls doesn’t suffer in the same way (although it does tend to be at a lower volume than music).

It can be tricky to figure out just how long to hold the center button down to activate your phone’s voice assistant without holding it so long that the Besign interprets it as your wanting to switch devices or pair a new one. We encountered similar issues with the other aux-in models we tested, but the Besign was one of the easier ones to manage.

Although it works for voice calls, this FM transmitter is best suited to music streaming. You can see which station you’re tuned to and easily find a new one.

May be out of stock

An FM transmitter takes your phone’s Bluetooth audio and transmits it over FM-radio frequencies to your car’s radio tuner, so it works with any stereo. After going hands-on with seven of the highest-rated FM transmitters we found, we’re confident that GOgroove’s FlexSmart X2 is the best because it sounds as good as or better than the competition when tuned to the same stations. In fact, the FlexSmart X2 sounded better than other FM transmitters, and it was comparable in sound quality to our aux-in pick. (To get such clarity, however, you need a clear FM frequency—something that isn’t always available, especially in urban areas, where the FM dial is crowded with stations.)

The FlexSmart’s FM transmitter performed relatively well in the strength and clarity of its signal when compared with an aux-in transmitter or a native Bluetooth system. It streamed music with practically no interference, providing the best audio fidelity of any of the FM units we tested—almost as good as a direct aux-in connection, with a slightly stronger midrange and slightly less focus on the highs. This surprised us, considering the usually poor quality of FM transmitters. As long as you find a good, clear frequency, you’ll be impressed with the results.

Voicemails we left using the FlexSmart X2 sounded better than those recorded using other FM transmitters in both our windows-down and windows-up tests. That’s not to say that outgoing audio was perfect or even great—after all, sound transferred through a phone, then over Bluetooth, and then over radio waves is bound to lose fidelity—but the X2 was the clear winner out of all the FM transmitters we tested. We also like that the X2 has multipoint pairing (so you can pair two phones at once), an aux-in jack for use with non-Bluetooth devices, and an arguably nicer overall design—it looks more sleek and more pleasant than other models we tested, some of which look clunky or intrusive in your car.

The FlexSmart’s 3½-inch-long base, which plugs into your car’s accessory-power outlet, hosts a 4-inch-long, flexible gooseneck; the unit’s control module is at the other end. This module has track-control and play-and-pause buttons, buttons for answering and disconnecting calls, a dial for tuning and adjusting volume, a screen that displays the current transmission frequency, an aux-in port, and a 1-amp USB port for charging your phone.

The FlexSmart X2 sounded better than other FM transmitters, and it was comparable in sound quality to our aux-in pick.

With the FlexSmart X2, each “notch” of the tuning dial moves the broadcast frequency (station) up or down one decimal number (for example, from 97.4 to 97.5), rather than the more common approach of browsing odd-numbered frequencies; still, it doesn’t take long to get to a particular frequency.

Although the X2 has an auto-scan feature that claims to automatically find the best (read: clearest) FM frequency for transmission in your area, we found, after extensive real-world testing, that it’s better to be able to manually tune. The auto-scan feature might hit on a good, open frequency, but in our testing it was just as likely not to. In fact, it picked a handful of even-numbered stations (98.2, for example) that aren’t even accessible in the United States. Ultimately, we preferred the X2 model’s granular, easily accessible control over models that have only auto-scan.

The Avantree CK11 offers the crispest, clearest phone quality at an affordable price, with one-button access to the voice-control features on your phone.

If your main use for in-car Bluetooth is making and taking phone calls, a dedicated speakerphone offers better voice quality than aux-in kits or FM transmitters do. After testing three top-rated models, we recommend the Avantree CK11 Wireless Handsfree Visor Car Kit. It’s the simplest to use while driving, thanks to straightforward controls that come the closest to feeling like a native Bluetooth setup. It pairs quickly and easily with your phone, and the CK11 delivers clear, crisp audio through its built-in speaker, all at a phenomenal price. Although it wasn’t the loudest, fullest-sounding, or fanciest-looking model that we tested, it still offered the best combination of features, usability, and sound quality at a great price.

In our voicemail tests, the Avantree CK11 produced loud, clear, intelligible audio whether the car was sitting still or driving down the freeway. We didn’t notice any echo, distortion, or interference, even with the windows cracked. When we were talking on the phone or using our phone’s voice assistant, audio came through loud and clear on the CK11’s single, 2-watt speaker. Our only call-related complaint is how quickly this model announces the name of an incoming caller: one time fast, before jumping to the ringtone sound, so you’re not prepared to process the words you’re hearing. But this is a minor issue.

The Avantree CK11 slides onto your car visor with an attached clip, and it has only three controls to worry about: an on/off switch; a mute button; and a volume knob that doubles as a multifunction button to activate Siri or Google Assistant, or to end a call in progress. By contrast, the other speakerphones we tested include a range of unnecessary built-in voice commands, such as one that requires you to say “Phone commands” before actually accessing the voice command capabilities of Siri or Google Assistant.

The Avantree’s rechargeable battery is rated for 20 hours of talk time or 600 hours of standby time. If you leave the Avantree switched to “on” when you leave the car, it will automatically shut down about 10 minutes after you leave Bluetooth range with your phone; it will then turn back on as soon as you return and open the car door, thanks to a built-in motion sensor. This allows for a swift, hands-free reconnection every time, while preserving battery life. And when the time does come to recharge, the Avantree includes both a USB cable and an in-car adapter, so you don’t end up stranded on the road with a drained device.

If you’re hearing a whine with the audio cable plugged into your car’s aux-in jack, as we have with some units, this is likely due to radio-frequency interference from your car, or even your USB charger. A ground-loop noise isolator should help eliminate the buzzing. (Some of the aux-in kits we tested, including the Besign BK01 and the Mpow 3 in 1 Bluetooth Receiver for Car, include an isolator in the box.) But be aware that there can be trade-offs. When we tried one with our previous top pick, the discontinued iClever Himbox HB01, it actually decreased the overall volume and bass response, and left a slight distortion buzzing over the audio; we found some Amazon reviewers who’d had a similar experience. This might not be the case with every isolator cable on the market, but given the chance of a loss of audio quality, a high-pitched background whine could be a fair trade-off.

Our previous top pick, the discontinued iClever Himbox HB01, produced even better voice-call and music quality than the Besign BK01. And we still think it’s a great choice if you can find it in stock.

The Mpow 3 in 1 Bluetooth Receiver for Car has a similar design to the Besign BK01, but the Mpow’s audio is noticeably grainier, and you have to push the center multifunction button to restart your music after a phone call. The included ground-loop isolator improves the sound quality somewhat by cutting back on the interfering frequencies, but the Mpow still loses more fidelity than we’d prefer, sounding more like a radio on a small, blown-out speaker.

We liked the Roav by Anker Bluetooth Receiver, and at first glance its low price makes it seem like a steal. However, it doesn’t include a 12 V USB car charger, and buying your own brings the Roav’s price in line with the Besign BK01’s. The Roav’s audio fidelity is also slightly worse (and quieter) than what you get with the Besign, although the Roav’s phone quality is a little better. You also can’t trigger your phone’s built-in voice assistant or skip tracks while listening to music or podcasts, which makes the whole experience rather limited.

We also liked the Anker Soundsync A3352, which had the next-best music quality to the Besign BK01. But its biggest appeal can also be its biggest flaw: The Anker Soundsync is a small widget that plugs directly into your aux-in jack. With no cable, you’re limited on where you can position the controls on the dashboard. This design could be a fine option if your aux-in jack is high on the dashboard. But it was a major problem in our test car, where the aux-in jack was located toward the bottom of the console. In that location, the microphone was barely able to pick up our voice, and we had to blindly grope around to find the button that changes the song. The A3352 also runs on a rechargeable battery, instead of a plug, and it doesn’t come with its own charging adapter.

The Taotronics TT-BR04 is the only model we tested that can be mounted on the car vents, rather than being attached to the dashboard with an adhesive pad. This makes it easier to reposition, if necessary, or to move between vehicles. The TT-BR04 was also the only model with an on-off switch; we’re not clear on why it has one, since this model powers off when you turn the car off, but if you want that option, then, hey, it’s there. The sound was decent overall, with slightly better phone quality than the Besign BK01’s and slightly worse audio for music and podcasts.

Kinivo’s BTC450 offers phone-call sound quality reminiscent of talking with your friends on walkie-talkies in the woods during childhood. We assume most people don’t want this, and, even if you do, it’s definitely not worth paying more than you would for the Besign BK01, just to take a meaty, distorted phone call.

The GOgroove SmartMini Aux was a previous top pick because it has great call and sound quality and a built-in battery. Instead of a round central unit that attaches to your dash, it consists of a small dongle that you can either plug directly into the aux input (if that input is close enough to the driver’s side of the car) or mount on a small Velcro pedestal, which you can then attach anywhere on the dash. However, the single-button interface can be a bit confusing, and although its battery life is decent (up to six hours on a single charge, according to the manufacturer), you must provide your own car charger, which adds to the overall cost.

SoundBot’s SB360 lacks a few key features—for example, it doesn’t have a hardware button that can trigger Siri or Google Assistant, and it doesn’t support multiple paired devices—and its audio quality earned tepid reviews from our testing panel. We do like the charger it comes with, which provides one 2.4-amp port, one 2.0-amp port, and a 1.0-amp port. But the charger isn’t enough to make up for this model’s the poor audio quality and missing features.

The Griffin Technology iTrip Aux Bluetooth takes up your car’s accessory-power port without providing additional USB-power ports, and it offers no physical controls.

The Nulaxy KM18 FM Transmitter is similar to our top pick, with a bendable gooseneck and an LCD display. The audio quality both for phone calls and music or podcasts is slightly worse but still serviceable. Unlike the GOgroove, the Nulaxy also has a slot for playing music directly from an optional SD card. (The LCD screen can display song information for the SD card, although not for phone playback.). However, you can’t access your phone’s built-in voice assistant from the Nulaxy’s controls.

The Roav by Anker SmartCharge F2 Car Kit plugs directly into your car’s 12 V power outlet, without a separate mic positioned closer to your face. So even though its voice quality is surprisingly good, that audio is noticeably quieter than that of other models we tested. The SmartCharge also doesn’t offer you a way to make outgoing calls without having to handle your phone. It works well enough as an FM transmitter for music and podcasts, but not quite as well as our pick, the GOgroove. The optional Roav app will supposedly help you locate your car in a large parking lot, if that’s something you need. (We didn’t test this feature, because even if it worked well, it wouldn’t lead us to pick the SmartCharge over the GOgroove.)

We previously recommended GOgroove’s FlexSmart X3, a newer version of our top FM pick. The base, which plugs into your car’s accessory-power outlet, hosts a long, flexible arm, like our pick. But the FlexSmart X3 didn’t perform as well as the FlexSmart X2. CNET’s Antuan Goodwin also reviewed this model and awarded it only 2½ stars (out of five), citing its poor auto-scanning and a high-pitched alternator whine (though we didn’t hear that in our tests).

As its name suggests, the GOgroove FlexSmart X3 Mini is a slimmed-down version of the FlexSmart X3. Instead of a long, flexible arm connecting its control pod and display to its charger plug, it has a short, rigid-plastic arm. However, our unit’s automatic tuning feature stopped only on frequencies that ended in even-numbered tenths (for example, 90.2); since all US radio frequencies have odd-numbered tenths, this is obviously a bug. Amazon reviews indicate that we’re not the only ones to experience this issue with the X3 Mini.

The Jabra Freeway has an FM transmitter, native voice commands, motion sensors, and good audio quality, thanks to its large built-in speaker. The trade-off is its size: At 3.8 inches long and 5 inches wide, the Freeway is too big to easily fit on a car’s visor. Yet despite its size, the Freeway lacks dedicated music-playback controls, instead relying solely on voice commands (such as “play,” “stop,” or “next track”). And when it’s using the FM transmitter, instead of playing phone-call audio through its own speaker, the Freeway sends that audio to your car stereo, resulting in a loss of quality. (We noticed similar quality loss while playing music.) Most annoyingly, the Freeway’s voice-command handling is very clunky, and you must use it even to access your phone’s own voice assistant: You have to push a button on the speaker and say “phone commands” before you can access Siri or Google Assistant. We found this extra step annoying, as well as distracting while driving.

The more affordable Jabra Tour suffered from the same phone-command frustrations as the Freeway, and though the Tour’s phone-call quality was remarkably good—better than even our top pick’s—that better call quality wasn’t enough to justify the Tour’s higher cost, especially since it’s harder to make and take calls on the road, because of this model’s clunky controls and voice commands.

We skipped over any speakerphone that didn’t have a built-in FM transmitter, including the SuperTooth HD Voice, the SuperTooth Buddy, and the Jabra Drive. Even though we generally aren’t impressed by FM transmitters, we think (given the limitations of a speakerphone’s small internal speakers) that it’s essential to have the option to play audio through your car’s speakers.

Nick Guy

Nick Guy is a former senior staff writer covering Apple and accessories at Wirecutter. He has been reviewing iPhones, iPads, and related tech since 2011—and stopped counting after he tested his 1,000th case. It’s impossible for him not to mentally catalog any case he sees. He once had the bright idea to build and burn down a room to test fireproof safes.

Thom Dunn

Thom Dunn is an associate staff writer at Wirecutter reporting on HVAC and other home improvement topics. Sometimes his curiosity gets the best of him, such as when he plugged a space heater and a Marshall guitar amp into the same power strip. Pro tip: Don’t do that.

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