How to Add Bluetooth Calling to an Older Car
Besign BK01 leads overall because a wired auxiliary connection sidesteps the static that ruins FM transmitters. Cars with only a radio should use Nulaxy KM18 instead. For calls alone, Avantree CK11 clips to the visor and puts the microphone above the driver’s head.
Fit the Besign BK01 Bluetooth Car Kit in any car with a 3.5mm auxiliary socket. Cars without one need the Nulaxy KM18 FM transmitter. Drivers who only want reliable calls should clip the Avantree CK11 to the visor and ignore the stereo entirely.
These kits solve one problem in three incompatible ways, so the wrong choice means either poor sound or no sound at all in your particular car. We compared how each routes audio to the speakers, where the microphone ends up relative to the driver, how each handles multipoint pairing, and what powers it, alongside owner reports on call clarity at motorway speed.
Before you buy
How do Bluetooth car kits send audio to your stereo? Three routes exist, and they are not equally good. A 3.5mm cable into the auxiliary input is cleanest, because no broadcast stage sits between phone and speakers. FM transmitters rebroadcast to your radio and inherit whatever noise already occupies that frequency, which is the price of working in a car with no aux socket. Self contained speakerphones skip the stereo altogether. Calls sound fine through them, music does not.
Which car kit gives the clearest phone calls? Distance from mouth to microphone decides call quality more than any published noise suppression figure. A mic sitting in the centre console is low down, near tyre roar and window reflections. Clip one to the visor and it hears your voice directly. Kits that put the microphone on its own lead let you choose that spot, which is why they beat units with the mic buried in the housing.
What to check in your car before ordering Two minutes of checking prevents the most common return. Look for a 3.5mm auxiliary socket in the centre console, glovebox or armrest. Then test whether the 12 volt socket stays live with the ignition off. Sockets that cut with the key will reboot a transmitter on every trip. Sockets that stay live will slowly flatten the battery when a kit is left plugged in for weeks.
Is multipoint pairing worth it for two phones? Multipoint holds two handsets connected at the same time, so a call to either rings through without repairing. Carrying a work phone beside a personal one is the case where that earns its place, as with the VeoPulse B-PRO 2B and the Avantree CK11. Single phone drivers gain nothing from it. Simpler kits that manage one connection often reconnect faster and drop out less.
The shortlist, ranked
Besign BK01 Bluetooth Car Kit
Audio leaves through a 3.5mm plug rather than the FM band, so station drift and static never enter the signal path. A microphone on its own cable clips near the visor, putting it far closer to your mouth than any console mounted body. Power comes over USB, and pairing resumes the moment the engine starts, so daily use needs no interaction at all.
Pros
- Wired path avoids FM interference completely
- Remote mic can sit level with your head
- Reconnects on ignition without a button press
Cons
- Useless in cars with no auxiliary socket
- Routing the cables tidily takes patience
Nulaxy KM18 Bluetooth FM Transmitter
Cars with nothing but a radio have exactly one option, and this is the transmitter owners recommend most often. A flexible gooseneck lifts the backlit display out of the 12 volt socket and into reach without leaning forward. Playback also runs from a microSD card, and a USB port charges the phone at the same time. Sound quality rests entirely on finding an empty frequency, which shifts as you travel.
Pros
- Works in any car that has an FM radio
- Gooseneck brings controls within finger reach
- Adds phone charging and card playback
Cons
- Needs a genuinely clear frequency to sound clean
- Interference returns when you cross into a new area
Avantree CK11 Bluetooth Visor Speakerphone
Clipped to the visor, the microphone sits directly above your mouth, which decides whether callers hear you over 70 mph road noise. Controls are large enough to answer without looking away from the road. Its own driver covers speech well and music badly, which is the trade for bypassing the car stereo. Standby runs for weeks between charges.
Pros
- Overhead mic gives the clearest voice pickup here
- Large buttons work without taking eyes off the road
- Holds connections to two phones at once
Cons
- Single driver is weak for music
- Needs recharging every few weeks
Anker Soundsync A3352 Bluetooth Receiver
Music first buyers get the cleanest wired feed into an auxiliary input. Higher quality Bluetooth codecs and a stronger analogue output stage separate this from generic receivers. Its microphone lives in the body, so call clarity depends on wherever the receiver ends up sitting. Battery power also lets it move to a home hi fi or an older set of speakers.
Pros
- Cleanest music playback of the wired kits
- Long battery life between charges
- Small enough to move between car and home
Cons
- Body mounted mic sits far from the driver
- Still requires a 3.5mm input in the car
Jabra Freeway Bluetooth In-Car Speakerphone
Three drivers in a virtual surround arrangement make this the rare visor unit worth playing music through. An FM transmitter is built in as well, so audio can go out through the car speakers when volume matters more than convenience. Motion sensing powers it up as you open the door, which removes the usual hunt for a switch.
Pros
- Fullest sounding speaker of the visor units
- Wakes on motion with no manual switch
- FM output available when you want more volume
Cons
- Larger than a minimal visor clip
- Costs more than a plain speakerphone
Kinivo BTC450 Bluetooth Hands-Free Car Kit
Setup ends after a single pairing: 3.5mm lead into the stereo, power lead into the 12 volt socket, done. No modes to select, no frequency to hunt, no app to install. Its microphone sits in the wired control puck, so call quality follows wherever you mount that puck. Owners report it reconnects on ignition without fail.
Pros
- Simplest install of the wired kits
- Reconnects reliably at every engine start
- Puck can be mounted within easy reach
Cons
- Microphone is in the puck rather than on a lead
- Occupies the 12 volt socket permanently
VeoPulse B-PRO 2B Car Speakerphone
Two handsets stay connected at once, and spoken prompts announce which line is ringing before you reach for anything. Voice guidance walks through the whole pairing process, so the manual stays in the box. Automatic sleep stretches standby into weeks between charges. Music through the single driver stays basic, as with every visor clip of this type.
Pros
- Keeps work and personal phones connected together
- Announces which phone is ringing
- Automatic sleep gives weeks of standby
Cons
- Speaker suits voice rather than music
- Chunky body sits awkwardly on a thin visor
The lineup, side by side
| # | Model | Audio path | Best for | Score | Price |
|---|---|---|---|---|---|
| 1 | Besign BK01 Bluetooth Car Kit | Wired 3.5mm auxiliary output | Best overall | 9.4 | Check price |
| 2 | Nulaxy KM18 Bluetooth FM Transmitter | FM transmission to the car radio | Best value | 9.2 | Check price |
| 3 | Avantree CK11 Bluetooth Visor Speakerphone | Visor clip | Best for calls | 9.0 | Check price |
| 4 | Anker Soundsync A3352 Bluetooth Receiver | Wired 3.5mm output | Best audio quality | 8.8 | Check price |
| 5 | Jabra Freeway Bluetooth In-Car Speakerphone | Three speaker array | Best speakerphone audio | 8.6 | Check price |
| 6 | Kinivo BTC450 Bluetooth Hands-Free Car Kit | Wired 3.5mm output | Best simple install | 8.3 | Check price |
| 7 | VeoPulse B-PRO 2B Car Speakerphone | Two phones simultaneously | Best for two phones | 8.0 | Check price |
Common questions
Do you need an auxiliary input for a Bluetooth car kit?
Wired kits such as the Besign BK01 and Kinivo BTC450 require one. Without an aux socket, an FM transmitter is the practical route into the car speakers, and a visor speakerphone handles calls without touching the stereo at all.
Are FM transmitters any good for music?
Their appeal is working in any car with a radio. Quality depends on locating a frequency nobody else is using, which is easy on rural roads and hard in cities where the FM band is packed. Expect to rescan when you drive between regions.
Which Bluetooth car kit is best for clear calls?
Anything that puts the microphone near your head. Visor speakerphones do this by design, and wired kits with a clip on mic lead achieve the same thing. Both beat a microphone sitting low in the console by an obvious margin.
Will a Bluetooth car kit drain my car battery?
Only in cars where the 12 volt socket stays powered after the key comes out. Check that first. Where the socket remains live, unplug the kit if the car will sit unused for more than a few days.
Can you connect two phones to one car kit?
Yes, on kits that support multipoint pairing, including the VeoPulse B-PRO 2B and the Avantree CK11. Basic FM transmitters usually manage one device at a time and need repairing to swap.
Do these kits work with Siri and Google Assistant?
Most include a button that triggers whichever assistant your phone uses, so voice navigation and dictated messages work as normal. Recognition accuracy tracks microphone placement and cabin noise more than the kit’s own electronics.
Can a Bluetooth car kit stream music as well as calls?
All seven stream audio. The difference is where the sound emerges. Wired and FM kits play through the car speakers at full volume, while visor units use a small internal driver that suits podcasts and struggles with music.
How do you stop the audio cutting out?
Keep the phone out of a metal lined pocket, a closed armrest bin or under a seat, since Bluetooth range is short and easily blocked. On FM transmitters, dropouts almost always mean the frequency has been claimed by a local station, so rescan for a quiet one.
Is a visor speakerphone better than an FM transmitter?
For calls, yes, because the microphone sits above your head instead of down in the console. For music, no, since a transmitter uses the car’s own speakers. Drivers who want both usually pair a wired kit with a remote microphone.
Final word
Fit the Besign BK01 in any car with an auxiliary socket, because a wired path removes the interference question entirely and the remote microphone can be placed where it actually hears you. Cars limited to a radio should run the Nulaxy KM18 and accept a frequency rescan now and then. Drivers who only want dependable hands free calling will be happiest with the Avantree CK11 on the visor.
