As a digital technology expert with over a decade of experience testing and reviewing electronics, I‘ve seen firsthand how transformative adding Bluetooth audio and hands-free calling can be to an older car. But for the many vehicles out there that predate the widespread inclusion of Bluetooth (generally before 2016 according to Consumer Reports), the options for bringing in smartphone audio are limited.
One of the most popular and affordable solutions is an FM transmitter. These devices plug into your car‘s 12V outlet (cigarette lighter socket) and broadcast audio from your phone over a low-power FM radio frequency that you tune your car stereo to.
While generally not as good sounding or reliable as a direct auxiliary cable or professionally installed Bluetooth kit, FM transmitters offer a simple, inexpensive way to bring Bluetooth audio to any car with a working FM radio.
In fact, despite the proliferation of other solutions, FM transmitters remain quite popular. The market for them in the US alone was estimated at over $25 million in 2019 and projected to grow to $30 million by 2025, according to Market Study Report.
To help you choose the best FM transmitter for your needs, I‘ve hands-on tested over a dozen of the most popular and highly rated models on the market. I evaluated them based on criteria including:
- Bluetooth version and stability
- Audio quality
- Display type and information shown
- Controls and ease of use
- Extra features like USB charging and SD card playback
- Build quality and reliability
Here are my top picks for the best FM transmitters that deliver a great user experience and value, broken down by category:
Best Overall: Nulaxy KM18
The Nulaxy KM18 ticks all the boxes you want in an FM transmitter at a very reasonable price usually under $20. It has rock solid Bluetooth 5.0 connectivity with A2DP audio support, an easy to read 1.44" LED screen, and convenient button controls for switching modes, adjusting volume, and skipping tracks.
On the audio front, the KM18 uses the latest Qualcomm QCC3034 Bluetooth chip and features noise cancelling CVC technology for crisp, static-free sound. In my tests, it consistently provided a strong, clear connection within my car and sounded near indistinguishable from a direct aux cable.
It also includes some appreciated extras like a large, stable gooseneck for flexible positioning, a USB-C PD and QC3.0 USB-A port for fast phone charging, a microSD card slot for direct playback, and even displays your car battery voltage to monitor health. A built-in microphone allows for hands-free calls as well and sounded above average in testing.
From excellent audio quality and reception to useful bonus features in an easy to use design, the Nulaxy KM18 is the best overall pick for most people.
Best Budget: VicTsing V5
If you just want a dead simple way to add Bluetooth to an older car stereo without spending much, the VicTsing V5 gets the job done for around $15. It delivers rock solid Bluetooth 5.0 connectivity in a compact design with a 1.8" color screen that displays the device name, song info, and FM station.
It sounds quite good for the price with a CSR Bluetooth chip and CVC noise reduction technology. The built-in microphone is clear enough for occasional hands-free calls and the inclusion of USB-C PD and QC3.0 USB-A ports let you rapidly charge your devices.
On the downside, there‘s no SD card slot or aux input and the screen is a bit dim and less informative than pricier options. But for basic, reliable Bluetooth audio and charging in any vehicle with a 12V socket, the VicTsing V5 is a great budget pick.
Best for Music Sound Quality: Sumind BT70
While no FM transmitter will rival a direct wired connection for pure audio fidelity, the Sumind BT70 comes respectably close. It supports the high-quality aptX HD Bluetooth codec (on compatible Android phones) and features a Qualcomm QCC3034 chip with DSP digital audio processing and CVC 8.0 active noise cancellation.
The result is clean, dynamic sound with good detail and bass response by FM transmitter standards. The BT70 also has excellent Bluetooth 5.0 range and stability, maintaining a strong connection even with my phone in the back seat.
Other niceties include a sharp, colorful 1.7" TFT display with ID3 tag info and album art support, a handy control knob for volume, both USB-C PD and QC3.0 USB-A ports, and support for 32GB microSD cards. The build quality is a step up from cheaper models with a sturdy metal gooseneck and attractive fabric wrapped cables.
If you‘re looking for the best audio experience possible from an FM transmitter, the Sumind BT70 delivers great sound, premium design, and loads of features.
Best for Frequent Call Use: Anker Roav SmartCharge F2 Pro
Those who spend a lot of work hours behind the wheel taking calls know how important a high-quality, reliable hands-free solution is. Anker has long been a go-to for great Bluetooth speakerphones and their Roav SmartCharge F2 Pro FM transmitter is purpose built for excellent call quality.
The star of the show is an adjustable gooseneck with 3 high-quality MEMS noise-cancelling microphones, allowing you to optimally position it for the clearest possible voice pickup. There‘s also a dedicated mute button and support for voice assistants like Siri and Google Assistant.
Dual USB-A ports (one 5V/2.4A and one QC3.0) keep your devices charged up for marathons on the road and Bluetooth 5.0 support ensures a stable connection. The monochrome OLED display shows the current FM station, battery voltage, and song info from your phone.
If you want to take calls that are loud and clear without needing to wear a headset, the Roav SmartCharge F2 Pro handles the hands-free heavy lifting brilliantly. It‘s one of the more expensive FM transmitters at around $45 but justifies it with fantastic call quality.
Best Display and Controls: Nulaxy KM29
While most FM transmitters tend to have small, basic LED or OLED displays, the Nulaxy KM29 goes all in with a huge 2.4" full color TFT LCD. It‘s the biggest and most vibrant display I‘ve seen on any FM transmitter and provides loads of useful info at a glance.
In addition to the dialed in FM frequency, it shows the full song title and artist, your phone‘s battery life, the current volume level, and even the type of audio file playing. It gets plenty bright but also has an auto-dimming sensor to reduce distraction at night.
The KM29 sounds quite good thanks to a Qualcomm QCC3034 Bluetooth 5.0 chip with aptX support, and has a solid feeling control knob flanked by large, clicky buttons for power, mode, and play/pause. Dual QC 3.0 USB-A ports provide rapid phone charging and a microSD card slot handles up to 128GB cards for direct music playback.
While not the cheapest option at around $40, the Nulaxy KM29 is hard to top if you appreciate a generously sized, informative display and quality tactile controls. The colorful, premium look is a nice bonus too.
Most Compact Design: Ainope Bluetooth 5.0 FM Transmitter
Sometimes you just want a way to add Bluetooth audio to your car without a big, potentially distracting screen and dangling cables. Ainope‘s tiny Bluetooth 5.0 FM transmitter couldn‘t be simpler, packing everything into a streamlined design not much larger than a typical car charger.
Despite the small size, it still includes a crisp OLED display that shows the current frequency, song name, incoming caller, and car battery voltage. It sounds pretty decent too, with CVC noise cancelling and a CSR Bluetooth chip. The built-in mic works fine for brief calls.
You get dual USB-A ports (QC3.0 + 2.4A) to keep devices juiced up on the go and the array of small buttons on top let you accept calls, skip tracks, and adjust the volume without taking your eyes off the road. The compact form factor tucks away nicely in most dashboards.
When ultimate simplicity and minimalism are top priorities, this Ainope FM transmitter is an unobtrusive way to bring Bluetooth to any car at a very affordable price.
How to Get the Best Performance from an FM Transmitter
Even the highest quality FM transmitters are still susceptible to some static, interference, and range issues. Here are my tips to get the best possible audio experience:
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Find the clearest FM frequency: Before settling on an FM station to broadcast over, do a scan of your local frequencies and choose one with no active stations nearby on either side. Avoid frequencies ending in odd numbers like 88.1 or 107.9, as these are more likely to experience interference according to audio company boss.
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Keep the transmitter close to your phone: While most transmitters I‘ve recommended have great Bluetooth range, you‘ll still get the strongest connection and best audio quality by keeping your phone within a few feet of the device. Consider a car phone mount for the center console or dashboard.
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Use the latest Bluetooth version: If you have an older phone that only supports Bluetooth 4.x, consider upgrading to a newer handset with Bluetooth 5.0. You‘ll enjoy faster pairing, longer range, and potentially higher quality audio codecs like aptX HD.
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Reduce other nearby electronic interference: Other electronics in your car like radar detectors, GPS units, and even LED light strips can cause interference with FM transmitters. Try turning them off temporarily if you experience a lot of static.
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Invest in a ground loop isolator: If your car experiences a lot of alternator whine or buzzing in the audio, a ground loop isolator can help eliminate it. These inexpensive devices (under $10) plug in between the FM transmitter and your car‘s 12v socket to filter out electrical noise.
While FM transmitters may not match the audio fidelity and reliability of a direct aux-in connection or purpose-installed Bluetooth car kit, they remain a useful and affordable way to bring smartphone audio into older vehicles. With the latest Bluetooth versions, high-quality DACs, and noise cancelling technologies, the best transmitters come surprisingly close.
So whether you‘re still driving that 90s Civic, an early 2000s SUV, or a modern classic from the 80s, there‘s an FM transmitter out there to keep your tunes flowing on the open road. Pick one of our expert-approved models and you can‘t go wrong.
FM Transmitter Comparison
| Model | Nulaxy KM18 | VicTsing V5 | Sumind BT70 | Anker Roav SmartCharge F2 Pro | Nulaxy KM29 | Ainope |
|——-|————-|————-|————-|——————————-|————–|—-|
| Bluetooth version | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
| Audio codecs | SBC, AAC | SBC | SBC, AAC, aptX, aptX HD | SBC, AAC | SBC, AAC, aptX | SBC |
| Chip | QCC3034 | CSR8675 | QCC3034 | Unknown | QCC3034 | CSR |
| Noise cancellation | CVC | CVC | CVC 8.0 | 3 MEMS mics | CVC | CVC |
| Display | 1.44" LED | 1.8" color TFT | 1.7" color TFT | 0.91" OLED | 2.4" color TFT | 0.96" OLED |
| Microphone | Built-in | Built-in | Built-in | Adjustable with 3 mics | Built-in | Built-in |
| Charging | QC3.0 USB-A, USB-C PD | QC3.0 USB-A, USB-C PD | QC3.0 USB-A, USB-C PD | QC3.0 USB-A, 2.4A USB-A | 2 QC3.0 USB-A | QC3.0 USB-A, 2.4A USB-A |
| SD card slot | Yes | No | Yes | No | Yes | No |
| Aux input | Yes | No | Yes | No | No | No |
| Controls | Buttons | Buttons, Knob | Buttons, Knob | Buttons | Buttons, Knob | Buttons |
| Price | $20 | $15 | $35 | $45 | $40 | $14 |
| Rating | 9/10 | 8/10 | 9/10 | 8/10 | 9/10 | 7/10 |
