IMDEN C57 Bluetooth FM Transmitter Reviewed

If you have an older vehicle, a Bluetooth FM Transmitter can be a great way to get audio from your modern device (smartphone, tablet, etc.) to your car’s audio system.

In this review we are going to be looking at the IMDEN C57 Bluetooth 5.9 FM Transmitter.

We will look at its sound quality, build quality, features and more. Skip to the end to check out our video review of this product as well.

How Much Does the IMDEN C57 Bluetooth 5.9 FM Transmitter Cost?

While prices do change overtime, we paid around US$17.99 for the IMDEN C57 Bluetooth 5.9 FM Transmitter. At the time of writing the price has crept up a dollar to $18.99. Compared to its competitors, this $18.99 price tag puts it in the middle bracket when it comes to cost for Bluetooth FM transmitters. However, we have also seen prices of under $15, so it pays to check out the Imden C57 on Amazon and then purchase/add to your watchlist to get the best possible price.


Below we have listed the specifications for the C57 FM Transmitter as per what IMDEN provided on the box.

  • Support agreement: A2DP, AVRCP, HFP and HSP
  • Frequency range: 88.1 – 107.9 Mhz
  • FM transmission distance: around 3 metres
  • Product input: 12 – 24V
  • Output: QC3.0 Fast charging plus 1A
  • Music format: MP3, WMA, WAV
  • USB: 64gb (Max capacity)
  • Product weight: 37g
  • Low power alert: flashing under 12v

First Impressions, Packaging & Size

The C57 Bluetooth FM Transmitter comes in nice sturdy, recyclable packaging. All the specifications (as listed above) are provided on the rear of the box. Unlike some other transmitters we have tested the only thing included in the box is the C57 itself. This isn’t a problem for us as we really don’t need any more crappy USB or audio cables.

The C57 itself is quite a compact device (see size below), so it doesn’t stick out like a sore thumb like some other transmitters. Additionally, it is shaped like a conventional cigarette lighter USB charger, which is a big plus in our eyes. Some of the transmitters we have tested have a strange shape that doesn’t play well with some cars.

The build quality is surprisingly good for the price and we are sure that it can take a bit of abuse. The ports are located in a good place as well at the front of the transmitter, but the buttons on the top can be a bit fiddley. Overall, our first impressions were really good and probably the best of all the transmitters we have tested up to date.

ScannerSize Without Packaging (L x W x H)
IMDEN C57 Bluetooth 5.9 FM Transmitter75 x 32 x 32 mm (2.95 x 1.26 x 1.26 inches)

 Connectivity and Instructions

Connecting IMDEN’s C57 FM Transmitter to both android and IOS devices was as simple as we could ask. When the transmitter is plugged in it will show the voltage of the car battery for 5 seconds. Once it has done this it will go into wireless pairing mode and the LED screen on the front will display the characters “bt”.

After you have plugged the C57 into your car’s lighter socket, go into the Bluetooth settings of your phone/device. The C57 should appear (it did it for us immediately on multiple devices) and you simply click on it to connect. We didn’t have to input a password to connect, but IMDEN does note in their instructions you may have to do so (password is 0000).

It is important to make sure that the frequency on the transmitter matches that of the one on the radio of your car. To do this on the C57 you press and hold (long hold) the button with the phone symbol on it. You will then notice that the current frequency appears on the front of the transmitter. You can then use the forward and back buttons to go up and down the frequency range to match the one on your car’s radio.

The C57 is limited to a frequency range of 88.1 – 107.9 Mhz, which covers the entire FM range in the United States. We tested the transmitter at various different frequencies within this range and found that it functioned correctly.

While we didn’t really need the instructions to work out how to connect the C57, we did give them a read. They are simple enough and gave a good overview of how to get the transmitter going and how to use its features. However, the instructions we received were only in English, so keep that in mind.

Sound Quality

Sound quality can be such a subjective thing, but most would agree that muddy audio with lots of interference is never a good thing. A lot of Bluetooth FM transmitters get a bad rap for terrible audio, but how does the IMDEN C57 perform?

In truth the audio isn’t as good as a wired connection and we never thought it would be. The sound quality is definitely a bit muddy, but we felt it was perfectly fine for us. If you are really into high fidelity audio this transmitter will probably disappoint (then again all FM transmitters will probably disappoint and you should just use a cable and/or upgrade your car’s sound system if you really want to go crazy).

Compared to other FM transmitters we have tested the IMDEN C57 definitely sits in the middle when it comes to sound quality. It isn’t quite as good as ones like the Avantree CK310 or the Nulaxy KM30, but to be honest we probably wouldn’t have noticed a difference if we didn’t do back to back testing.

There is no ability to adjust the bass or treble like some other transmitters, but often these features are more gimmicks on Bluetooth FM transmitters, so we are not overly concerned about the lack of them.

Overall the C57 is average when it comes to sound quality, but we really didn’t expect anything else when purchasing an FM transmitter.

Operating the C57

Playing Music

You can either control music through your phone or by using the buttons on the C57 FM transmitter. If you are playing the music through a USB flash drive you will have to use the buttons on the transmitter. The process of using the buttons on the C57 transmitter to control music is simple, but we have outlined them below:

  • To play music press the phone/call button. Press the button again to pause the music
  • Press the back button to play the next song and the forward button to play the previous one (not sure why IMDEN has it this way around, but we got used to it pretty fast)
  • If you want to change the volume press and hold the back button to turn the volume up and then the forward button to turn it down. You will see the level appear on the front of the transmitter.

Sometimes we did find that the C57 changed songs when we wanted to control the volume and vice versa. This was somewhat annoying, but it didn’t happen frequently enough to make it a major issue to us.


Another benefit of using a Bluetooth FM transmitter is that you can take and receive calls. To answer an incoming call on the C57 you simply press the phone button and if you want to hang up you press the same button again. You can then redial the last number by pressing the phone button twice. If you want to properly dial a number you will need to do that off your phone.

If you don’t want to answer a phone call for whatever reason, you simply long press the phone button and it will reject the call.

The call quality is much the same as the sound quality for playing music, so we had no problems with it. Once again it was a little bit muddy but perfectly usable for calls.


Like many other FM transmitters on the market, the IMDEN C57 has charging ports for your devices. The main charging port is a QC (Quick Charge) 3.0 Fast Charging Port, while the other one is a simple 5V/1A one that is also used for connecting USB flash drives.

The Quick Charge 3.0 port theoretically allows you to charge a phone with a 3,500mAh to 4,500mAh battery to 80 percent in as little as 35 minutes when the battery is fully depleted. This is a nice feature to have, especially if you forget to charge your phone. The 1A port is much, much slower and should only be used if you want to charge two devices at once.

While one of the charging ports isn’t the fastest, having two ports with one of them being QC 3.0 rated puts the IMDEN C57 above many of its competitors.

Conclusion – Imden C57 Review Recap

Overall, the IMDEN C57 is a good Bluetooth FM transmitter. It offers more than enough features, comes at a fairly good price, is the best form factor of any FM transmitter we have tested, and the sound quality is adequate. We have tested some better sounding transmitters but these are more expensive and/or come with less features. If you are looking for a solid mid-range option for your car this is it, just don’t go in expecting hifi levels of sound quality.

If you would like to read a full comparison of some of the FM transmitters we have tested, check out our article here on the Best Bluetooth FM transmitters for your car.

You can purchase your Imden C57 here.

Imden C57 Video Review

You might also like to watch our video review of the Imden C57 (which is also our first-ever product review video) for a more in-depth overview of the product, and its pros and cons:


  • Ben

    From his early days playing the original Gran Turismo and with his Hot Wheels car set, Ben has had a long interest in all things automotive. His first foray into the world of automotive journalism was way back in 2009 and since then he has only grown more interested in the industry. Ben also runs and heads up the video production side of Garage Dreams, focusing on small informative documentaries about some of the world's most legendary cars.

3 thoughts on “IMDEN C57 Bluetooth FM Transmitter Reviewed”

  1. Bluetooth technology allows you to transfer data from one device to another wirelessly. It works with any compatible device that comes with Bluetooth chips, also known as Bluetooth radios. In everyday conversation, Bluetooth radios can also mean radio devices that enable a Bluetooth connection, such as a radio. B. a SiriusXM Bluetooth car stereo.

  2. It’s a microchip embedded in Bluetooth-enabled devices like smartphones, tablets, and laptops. Sometimes the term also refers to two-way radios that have Bluetooth capabilities.


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