Is AUX Better Than An FM Transmitter For Audio Playback?

One of the best things about modern cars is their audio playback/connectivity capabilities.

Even the cheapest of new cars will let you hook up your phone to the car to play back music and make or take calls, usually via the magic of Bluetooth.

Say what you will about new cars often feeling rather soulless to drive – there is something great about having up-to-date connectivity.

But what about those of us with older cars?

Whether you’re driving an older car out of choice or necessity, there’s no doubt that things can feel a little bit limited when it comes to audio playback and connectivity.

In previous articles at Garage Dreams we have covered various options for improving the audio connectivity of your older car – I recommend starting with our comprehensive guide to older car audio options.

However, in this particular article we are looking at whether it is better to use AUX or an FM transmitter if you want to enhance the audio connectivity of your older car. You might also like to read our roundup of the best Bluetooth FM transmitters if you are looking at one of these products for your car.

Is Aux Better Than FM Transmitter Devices For Aftermarket Audio Playback?

When doing “head to head” comparisons I’m usually in favor of doing a detailed comparison, and really getting into the pros and cons of each option.

However, when it comes to using AUX or an FM transmitter, the choice is simple – AUX wins, just about every time.

AUX is definitely better than using an FM transmitter.

The main reasons are:

  • AUX provides a more reliable connection than using a Bluetooth FM transmitter. Even if you use a Bluetooth AUX adapter (i.e. a device that plugs in to the AUX input and then lets you connect your phone to the device via Bluetooth) you should enjoy a better, more reliable connection as you don’t have the challenge of trying to broadcast the device signal to your stereo via an empty radio frequency. If you use a fully-wired connection, things should be even more reliable!
  • AUX inputs and devices tend to have better sound quality. Ultimately the sound quality will be limited by your car stereo’s capabilities, but certainly a “direct” input into the stereo – as opposed to radio – tends to carry superior sound quality. If you fancy yourself a bit of an audiophile, then you are going to be happier with the audio from an AUX direct input or adapter.
  • AUX is easier. The biggest frustration/challenge you are likely to encounter these days is that many phones do not come with an AUX output, in which case you will need to use an adapter (e.g. USB-C to AUX) or you’ll want to use a a Bluetooth AUX adapter that allows you to connect your phone wirelessly. However, either of these options is easier to use than a Bluetooth FM transmitter.
  • AUX is less expensive. It’s cheap to buy an AUX cord (chances are you’ve probably got one lying around already). You can buy an AUX cable from just about any convenience store, service station, electronics store etc so it’s a very accessible option if your car has the appropriate input.

The one major advantage I can see for using an FM transmitter is that these all tend to come with hands-free call ability out-of-the-box. However, you can overcome this limitation with AUX by investing in an adapter that has phone call functionality.

One other advantage to using a Bluetooth FM transmitter is that you probably won’t need any kind of adapter for your phone. On the other hand, many new smartphones don’t come with headphone jack (i.e. AUX output) so you might have to invest in an additional adapter in order to be able to use your phone with an AUX device.

Conclusion – Is AUX Better Than Using An FM Transmitter?

Yes, 100% – it is better to use AUX than using an FM transmitter.

If you have an AUX input in your car, then use that over an FM transmitter.

If you just want to be able to playback music (songs, podcasts etc) then plugging your phone directly into the AUX input – via an adapter if needed on a phone without a dedicated headphone jack – is going to be the easiest way to go.

If you need additional connectivity, e.g. the ability to take and make calls, then an AUX hands-free adapter is going to be your best bet, and should perform to a higher standard than a a Bluetooth FM transmitter.

In my view, there is just no argument for using an FM transmitter if you have AUX connectivity in your car.

With AUX you are going to enjoy superior sound quality, easier setup, and greater reliability. It is a simpler, more elegant, and more effective solution.

If you’re a sucker for punishment, then using a Bluetooth FM transmitter when you have the option to use AUX is obviously something you can do, but in good conscience I cannot recommend this when AUX is available.

However, if you do want to try an FM transmitter for some reason, then check out our guide here to the best Bluetooth FM transmitters. We have gone “hands on” with some of the most popular FM transmitter devices on the market, in order to determine which is the best.

If you have any questions or concerns, feel free to leave a comment below. Thank you for reading!


  • Sam

    Sam focuses mainly on researching and writing the growing database of Car Facts articles on Garage Dreams, as well as creating interesting list content. He is particularly enthusiastic about JDM cars, although has also owned numerous European vehicles in the past. Currently drives a 3rd generation Suzuki Swift Sport, and a Volkswagen Touareg (mainly kept for taking his border collie out to the hills to go walking)

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5 thoughts on “Is AUX Better Than An FM Transmitter For Audio Playback?”

  1. For iPhones, the last iPhone to offer a headphone/aux out jack was the 6s; every iPhone since has only a Lightning connector. However, Apple as well as the aftermarket (search Amazon) offer short dongles (is that redundant?) with a Lightning plug at one end and a headphone/aux jack at the other so that you can connect the iPhone to an aux jack (or use headphones, etc.). Some (recommended) offer an additional input on the dongle to plug in a Lightning charger cable which works contemporaneously so that you are not depleting the iPhone’s battery charge while playing tunes or podcasts or indeed what may come over the cell connection (many radio stations also stream online, although you consume data under your plan while doing so, look for an unlimited data plan to dodge this problem). I am not aware of any ability to take or make calls with such a dongle, however, although my 2012 car offers, in addition to an aux input, a bluetooth connection to the iPhone, but only for calls, not for music or podcasts, so I’m covered.

  2. Thank you very much for this comparation.

    I was between ( rca aux in + BT transmiter ) and ( FM transmiter) Now is clear, I chose aux in + bluetooth transmiter in

    • No worries Timo, glad you can like it.

      I would take AUX every time over FM transmitter. They just aren’t anywhere near as good.

      Please consider sharing our site with your friends if you find it helpful.

  3. 2023, still a really useful article. I usually search for content in English, as there’s a higher audience and web contributors sharing info compared to Romanian.
    There’s a big number of aftermarket cars in RO, and lots of solutions, either no name or reliable brands. Anyways, with an AUX cable, I believe the solution is easy, as it’s just a simple cable, thus few chances that any producer (mostly Chinese products are available here) would screw it.
    I don’t use phone calls that much whilst driving, and there’s no law in Romania against driving whilst on speaker. Not the best phone call experience, but still, that’s not needed.
    Thanks Sam for sharing!


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