Reviews You Can Rely On

Best FM Transmitter of 2021

We tested FM transmitters from Nulaxy, Anker, Tecboss, and others to find the best models
Credit: Laura Casner
By Nick Miley and Michelle Powell  ⋅  Jul 27, 2021
Our Editors independently research, test, and rate the best products. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Learn more
If you're looking for an FM transmitter, we're here to help. We bought and tested 8 of the leading products available in 2021. Our team of audio and electronic experts tested these products thoroughly in practical scenarios. Specifically, we looked at the quality of the transmitted sound, the intuitiveness of operation, the shape of the unit and what conditions they are best suited to. Additionally, we cataloged features such as port types, and microphones. So, if you're ready to get to bumping beats or seamlessly streaming podcasts, keep reading because there's almost certainly a product here to fit your needs.


1

Best Overall FM Transmitter


Nulaxy NX12


USB port (#): Yes (3) | Bluetooth Connection Confirmation (type): Yes (beep)
Compact
Volume dial
Hard to access ports
Slight buzz when charging

The Nulaxy NX12 is a compact FM transmitter that has about the same profile as a standard USB car charger. The unit transmits loud, clean sound with strong bass that is amplified with an optional bass booster feature. Despite the compact size, the unit sports three ports (a Quick Charge 3.0, Type C PD 18W, and a standard USB port for thumb drives or direct connection of a phone or MP3 player), a volume knob as well as a channel button and display. Additionally, answering incoming calls is as easy as pressing the volume knob and speaking into the unit's built-in microphone.

While we appreciate the compact size of the NX12, we did experience some frustration with the positioning of both the QC and USB-C ports. When the unit is plugged in, these ports are almost flush with the car socket, making accessing them a little challenging without unplugging the unit. Additionally, when the unit is charging a device such as a phone, it produces a slightly fuzzy sound quality. That said, this transmitter has some of the best sound quality in the class and the fuzziness is quite mild compared to some other contenders.

Compact and feature packed, this unit earned the appreciation of all...
Compact and feature packed, this unit earned the appreciation of all for its effectiveness and ease of use.
Credit: Laura Casner

2

Best for Large LCD Display


Nulaxy KM18


USB port (#): Yes (1) | Bluetooth Connection Confirmation (type): Yes (voice)
Loud
AUX port
Bulky
Flimsy neck

The Nulaxy KM18's defining feature is its large LCD screen that keeps the user appraised of the volume level, the radio frequency being transmitted, the name of the connected device, and even the voltage of the port that it's plugged into — this last feature is an indicator of the car's battery health. The screen is mounted on a flexible neck that makes positioning it a cinch. Additionally, the unit has a volume knob and track navigation, and radio channel +/- buttons. Rounding out the suite of features is an AUX port (which allows a direct connection to the headphone port of your device), a 5V/2.1A USB port, and a micro SD input for reading MP3 files directly.

While the KM18 is packed with features, they come at the cost of size. That is not to say that this transmitter is overly big, but it's not what we'd call low profile either. Moreover, the large display screen is a bit heavy for its spindly neck and can result in the unit moving away from the user as she pushes, for example, the phone call receive button. However, the length of the neck may be a boon for those with electric sockets deeply set in the car's console. If the size of this unit suits your needs, then you'll be happy to know that it delivers a very loud, high-fidelity sound.

This unit offers users a ton of info in its amply-sized user...
This unit offers users a ton of info in its amply-sized user interface. Oh, the sound quality is top-notch, too.
Credit: Laura Casner

3

Best Bang for Your Buck


Nulaxy NX10


USB port (#): Yes (2) | Bluetooth Connection Confirmation (type): Yes (voice)
LED backlighting
Super loud
Fiddly to change FM frequencies
Rigid display orientation

The Nulaxy NX10 is a screaming deal by our estimation. The unit is compact, has an easy to use phone answering/volume button/knob, a built-in microphone, and 2 USB ports — one of which is of the Quick Charge variety. As if that wasn't enough, the unit boasts tons of flair with its customizable, 7-color LED light spread including backlit ports. Fleshing out the package is very loud volume and heavy bass transmission that maintains clarity of sound.

Unfortunately, this unit is not without its shortcomings. First of all, some people might not like the light show. And, while one can change the color, you can't turn the lights completely off. Another issue is that the radio frequency adjustment is a bit convoluted requiring a two-step process. Finally, there isn't an AUX port. However, we think the micro SD card port more than mitigates this lack, making this the go-to budget transmitter.

This competitively priced unit offers much of what the higher-end...
This competitively priced unit offers much of what the higher-end machines boast but with a slight decrease in sound-quality.
Credit: Michelle Powell

4

Best for Hand-Free Phone Calls


Tecboss TB27


USB port (#): Yes (2) | Bluetooth Connection Confirmation (type): No
Air vent mount
AUX port
Two-step frequency change
Bulky

The Tecboss TB27 is a two-piece unit that connects the power plug to the user interface/transmitter with a cable. This design has the benefit of bringing the built-in microphone closer to the speaker's mouth as well as allowing flexibility in the location of the interface screen. The microphone's sound transmission is not only improved by proximity to the speaker but also by noise suppression software that further cleans up the quality of the sound. The transmitter has 2 USB ports — 1 Quick Charge — as well as a micro SD card and AUX input. Finally, answering calls is as easy as pushing the large button on the left side of the display.

Despite our affinity for an easy way to answer calls and the improved clarity provided by the built-in microphone, we do not like the cable that necessarily drapes across the console. In our opinion, cords are unsightly and create a cluttered look. Additionally, we do not like the frequency/channel adjustment process, which requires the user to hold down the track navigation buttons on the top of the display to toggle their function. Despite these issues, this is the best voice service unit of the bunch, and the sound quality is quite good to boot.

The vent-mounted user interface brings the controls and the...
The vent-mounted user interface brings the controls and the microphone closer to the user but this comes at the cost of having a cord running across the console.
Credit: Michelle Powell

5

A Good Option for Frequency Adjustments


Sumind Wireless Radio Adapter


USB port (#): Yes (2) | Bluetooth Connection Confirmation (type): Yes (beep)
Frequency buttons
Quick Charge USB port
No USB-C port
Lackluster sound quality

The Sumind Wireless Radio Adapter is a decent quality transmitter with a large LCD screen providing the user with a host of data. Specifically, the screen displays the name of the device connected, the volume level, the radio frequency that the unit is transmitting, whether a Bluetooth connection has been established, and the name of the program being played. The user interface conveniently includes frequency/channel buttons (a feature we really appreciate), track navigation buttons, a volume dial and phone call receive/disconnect button. The unit also has a built-in microphone for hands-free calling.

While the Sumind looks much like its higher-end counterparts, it shows its true colors — or sounds as it were — in its transmission quality. To be fair, the sound is clear, but it is not very loud. Similarly, bass is present but not very strong. Further muddying the sound is a slight fuzziness that increases as the volume is turned up. As a final consideration, the unit is very big — which could be a good thing if your vehicle's electrical socket is deeply set in the console — but, in most cases, will be an encumbrance. Accordingly, it is our opinion that, for the money, one can do quite a bit better than this device.

Models with large user interfaces make it easier to access features...
Models with large user interfaces make it easier to access features such as track navigation and frequency buttons.
Credit: Laura Casner

6

A Low-Profile Transmitter with a Broad Face


AINOPE FM Transmitter


USB port (#): Yes (3) | Bluetooth Connection Confirmation (type): Yes (voice)
Quick Charge USB port
CVC microphone
Broad user interface
Two-step frequency adjustment

The AINOPE FM Transmitter is a ho-hum device with marginal test results. It is true that the unit boasts 3 USB ports (Quick Charge 3.0, PD 3.0, and type C), Clear Voice Capture (CVC) microphone, and adjustable backlighting. However, these attributes pale when the unit's sound transmission is compared to the leaders in the class.

What is it exactly that turned us off to the AINOPE's sound quality? Like all low quality transmitters, this unit is fuzzy, bordering on crunchy. Additionally, background static is issued when charging a device through the transmitter. Another concern is the broad user interface capping the socket plug which may not fit all vehicles. All in all, it is our opinion that you can get a much better performing device for around the same amount of money.

This unit has some nice features nested in a compact interface...
This unit has some nice features nested in a compact interface though its sound quality leaves a lot to be desired.
Credit: Laura Casner

7

A Minimalistic Transmitter


Anker Roav SmartCharge F0


USB port (#): Yes (2) | Bluetooth Connection Confirmation (type): No
Simple design
Sleek
No Quick Charge USB port
Sound distortion when charging

Unfortunately, the Anker Roav SmartCharge F0 doesn't really live up to its name since it lacks a basic Quick Charge USB port. But, at least the unit has two USB ports, so you don't have to fight with the copilot to charge your device. As an added bonus, the unit has an echo canceling microphone to aid in hands-free gabbing on the phone.

Usually this is the paragraph where we would list the features that are lacking and the areas where this model fails to meet the standards set by the competition. However, the Anker Roav lacks so many features and transmits audio so poorly that it's better to simply point out that for the same dollar amount you can get a model that works properly. That is to say, a model that delivers loud, high-fidelity sound with a whole lot more features to make your time in the car more enjoyable.

This unit has a snappy look but lacks where it counts.
This unit has a snappy look but lacks where it counts.
Credit: Michelle Powell

8

A Subpar Device


LIHAN Dual USB Port


USB port (#): Yes (2) | Bluetooth Connection Confirmation (type): Yes (voice)
Minimalistic
Compact
Really poor sound
Two-step frequency adjustment

The LIHAN Dual USB Port looks a lot like a high-end transmitter but we're here to tell you that it falls short of this superficial impression. Yes, it has a faux carbon fiber shell that looks snappy, its black with orange accents have an urban flair, and its minimalistic user interface is a nod to Scandinavian design. However, this is where the complimentary critique ends.

At its essence, a transmitter has one job and that is to transmit audio that is true to its source through a radio frequency that a car stereo can receive. That's it. In our testing, the LIHAN failed to deliver on this modest expectation.

Be warned: this ho-humm device cost the same as units that deliver...
Be warned: this ho-humm device cost the same as units that deliver Hi-Fi sound.
Credit: Michelle Powell

Why You Should Trust Us


Senior Research Analyst Michelle Powell and Senior Review Editor Nick Miley have long driven cars with outdated stereos that are closer in age to 8 tracks than MP3s. They have bridged this technological gap with transmitters. As such, they are acutely aware of the benefit of this simple device and the difference between high and low-quality models. This prolonged personal experience using transmitters combined with years of tech product reviews focused on digital audio products such as earbuds and speaker bars make them perfectly poised to pounce on these products and share their findings.

The review class queued-up on a test day.
Testing for ease of use features is a key component of our analysis.
We favored models that didn't have cords drapping ove the dash.

While our side-by-side testing methodology for FM transmitters was not overly complex, it was nonetheless thorough and revealing. We broke up our analysis into four categories — what we call metrics. Namely, these are sound quality, ease of use, profile, and features. As the names imply, these metrics focus on the fidelity of the audio transmission, the operation of each model, the shape and organization of the interface as well as the pros and cons of the components. In a word, the analysis is exhaustive.

Analysis and Test Results


The FM transmitter market appears to be flat and simplistic, however, this is not the case. When one listens to a variety of musical genres transmitted through one device after another it becomes clear that similar looking, and comparably priced machines perform at drastically different quality levels. That's where we can help you. Allow us to spend the money and time to buy all the leading models and test them. The following is a report of such an endeavor, and it lays out how we tested, and more importantly, which models performed well and why.

Sound Quality


As the name implies, the sound quality metric takes stock of the sound that comes out of the car stereo and how true it is to the original — what in music parlance is known as fidelity. While a high-quality transmitter won't make a low-quality car stereo sound better, it should nonetheless deliver clear, loud, static-free sound across a variety of audio genres. The Nulaxy models, as well as the Tecboss, all transmit high-fidelity (Hi-Fi) sound. However, the Nulaxy NX12 issues a slight buzzing when a device is being charged through one of its USB ports. This, unfortunately, is a common issue with the lower-ranked products here reviewed. The NX12 is unique in that it has superb sound output when not charging.

While we like a feature packed transmitter, it all comes down to the...
While we like a feature packed transmitter, it all comes down to the fidelity of the sound coming out of the radio.
Credit: Michelle Powell

Our team's ears are well trained to analyze sound quality. Part of this analytical skill is the experience to sort out the aspects that are lacking when the quality is low. To be honest, when using a run of the mill car stereo, this isn't that tall of an order. What we want to have is little to no background static, humm and/or buzz as these noises dull the overall sound. We also want our bass to be felt rather than heard and we want the subtleties of individual notes to come through. Fuzzy bass is a dead give-away of low fidelity (Lo-Fi) transmission.

We really liked the bass booster on this model especially for those...
We really liked the bass booster on this model especially for those tunes that warrent a little extra bump.
Credit: Michelle Powell

Ease of Use


No one wants to spend tons of time futzing with a little electronic device just to get a little music going to enrich their drive. As such, we place a high value on the ease of operation of the transmitting device. The main issue with transmitters is changing the FM frequency. This action is a necessity because when there is a station broadcasting on the selected frequency it can overwhelm the transmitter's signal, thus reducing the quality of the sound. As such, we favor units with frequency or channel buttons and a clear screen displaying the frequency being transmitted. Models that met this standard are the Nulaxy KM18 and Sumind. Unfortunately, most models require a two-step process to make adjustments to the frequency.

As far as ease of use features go, models that have...
As far as ease of use features go, models that have frequency/channel button are perferred.
Credit: Michelle Powell

Of course, straightforward frequency adjustments are not our only concern. We make a holistic analysis of the user interface as well. Key points of interest are the placement of the input ports, the ease of fielding phone calls, and a confirmation of whether or not a Bluetooth connection has been established. When looking at all of these components collectively, the Nulaxy NX12 stands apart from the class for its overall ease of use.

This little unit pretty much has every feature one could want --...
This little unit pretty much has every feature one could want -- ports, channel button, receive/disconnct call button, volume -- all in an easy to use interface.
Credit: Michelle Powell

Profile


Profile preference is specific to the needs of the user based on the location of the electrical socket in the vehicle as well as the display type and features (see below) that they desire. That said, we favored models like the Nulaxy NX12 and NX10 that are compact (more like a car charger in appearance) as we dislike a cluttered console and large, bright screens.

Ya gotta like the clean and compact profile of this transmitter.
Ya gotta like the clean and compact profile of this transmitter.
Credit: Michelle Powell

Having been clear about our bias, if you are interested in a model that does have a larger screen, or just a bit bigger user interface, there are several high-quality models that have larger profiles. The Nulaxy NX10 is a good option if you want to keep the profile to a minimum but still like to have a volume knob and track navigation buttons prominently displayed.

As seen here, some units are better suited to a vertical orientation.
As seen here, some units are better suited to a vertical orientation.
Credit: Michelle Powell

Features


Not surprisingly, several models that did poorly in the profile analysis did well in the features department. Machines like the Sumind with more features on offer typically require more real estate. These features include information such as Bluetooth connection, volume level, the radio frequency being transmitted, and the name of the connected device, as well as hardware ports such as Quick Charge USB, micro SD, and AUX.

The units with large user interfaces are without doubt the best...
The units with large user interfaces are without doubt the best suited for packing in features such as track navigation and frequency buttons.
Credit: Michelle Powell

The features metric also looks at the user interface. As such, it takes note of the array of buttons and knobs controlling radio frequency, volume, and track navigation. As a testament to Nulaxy's thoughtful designs, the NX12 excels in both the profile and features metrics. Our hat is off to this transmitter as it boasts 3 USB ports, volume/phone call receive knob/button, frequency display as well as a built in microphone while maintaining a profile similar to a simple USB charger.

The NX12 is simply the best designed unit in the class.
The NX12 is simply the best designed unit in the class.
Credit: Michelle Powell

Conclusion


This comprehensive review of FM transmitters covers every aspect of design and functionality. We tested these products side-by-side for sound quality, ease of use, profile, as well as cataloging their features. The results of this analysis are organized in a manner that allows one to quickly and accurately parse the models that fit their needs and wants. With that, here's to getting crystal clear audio without having to dish out hundreds of greenbacks for an unnecessary car stereo.

Nick Miley and Michelle Powell