I’ve been reluctant to swap out my car stereo for a new one. I have a second generation Scion XB with the upgraded Pioneer receiver, which has some novelty startup effects, and pretty decent sound. In general, if something works, I will keep it until something new is absolutely necessary. I thought about getting a Bluetooth to auxiliary adapter so I could wirelessly connect my phone to the car, but I’ve never trusted wireless to produce good enough results. My opinion changed somewhat when I got a new Wireless AC router and got over 600Mbps across the house on a laptop, so why couldn’t Bluetooth show the same improvements?

In comes Bluetooth 4.1 and Qualcomm’s aptX audio codecs, which offer higher quality audio at lower bitrates.

Now, I’m aware that Bluetooth 5.0 is here, but there are few devices that currently support this and my phone is not one of them. So with that in mind, I was sent a Bluetooth device from Audew, who we recently reviewed a jump starter from. The Bluetooth device acts as a transmitter or receiver for audio and has some interesting use scenarios that I can think of.

3 potential uses:

• Wirelessly play music from your phone in a car that does not have Bluetooth.
• Wirelessly connect your phone to a home theater or headphones.
• Wirelessly transmit plugged-in audio source to one or two Bluetooth headphones.

The adapter has two modes:

1. Receiving audio from Bluetooth and outputting it to a wired audio device.
2. Transmitting audio from a wired audio device over Bluetooth.

The transmission mode (TX) lets you take audio from either the auxiliary port or an optical in port and transmit it to one or two Bluetooth headphones. This can be useful for using wireless headphones in your home while someone is sleeping or pairing a wired device to a bluetooth speaker.

The receiving mode (RX) lets you take a bluetooth source, such as your smartphone, and send the audio out through either the auxiliary port or the optical out port. You can use this in a car to wirelessly send audio from your phone to your older car stereo. Alternatively, you could send audio from your phone to your home theater, sound bar, or wired headphones.

Physical Specs:

• Measures 6 x 6 x 2 cm
• 450 mAH Li-Poly battery
  • Supposed to last 18-20 hours
• 3.5mm AUX input / output
• S/PDIF Optical Audio Input
• S/PDIF Optical Audio Output
• Transmit (TX) / Receive (RX) Switch
• Power Button
  • Hold for 5 seconds to power on
• Pair button for pairing devices
  • Hold for 3 seconds to pair
  • Hold for 8 seconds to clear memory
• Next and Previous buttons

Technical Specs:

• Bluetooth 4.1
  • A2DP/AVRCP
  • Qualcomm aptX-LL for low latency (sub 40ms) audio
    • Supports 48kHz / 16bit LPCM audio data
    • 16-bit/44.1kHz audio with a compression ratio of 4:1 at 352kpbs

Includes:

• 2 meter microUSB cable
• 1.2 meter 3.5mm AUX cable
• 1 meter 3.5mm AUX to Stereo RCA cable
• 1 meter optical audio cable (TOSLINK)

Testing the Device

When I got the device in, I grabbed my smartphone to get it connected. The initial setup was a little odd, but I was able to figure it out. You press the power button in the middle for 5 seconds to turn the device on. You then press and hold the pairing button for 3 seconds to place the device into pairing mode. From your phone or other Bluetooth device, find TD-02 in the Bluetooth device list and pair it. If it prompts for a code, the default for all Bluetooth devices is “0000” or “00000” — it didn’t ask for it on my phone.

The part that I missed was the Bluetooth adapter was in TX mode, which means it is looking to transmit sound from a wired device to a Bluetooth device. In order to switch it back to receive mode (RX), you have to turn the device off, switch it to the other mode, then repeat the pairing steps. Once I got passed that, I was able to play my music library through my car stereo over Bluetooth.

Now, my car isn’t exactly audiophile level, but nonetheless, I could not tell the difference between the Bluetooth audio quality and that of the original CD I had in the car with the same audio tracks. That being said, I wanted to investigate further.

I took out my pair of Logitech Ultimate Ears headphones and put it to the test. I wanted to be able to do an A/B blind test, unfortunately I had to settle for testing both devices with the same music and trying to discern any differences in the audio. I started off by playing music I listen to on a regular basis — Rush and Foo Fighters. I added some Daft Punk to the mix so I could have music that was created digitally. I would play music over the headphone adapter for my smartphone, then listened to the same track with the headphones plugged into the device over Bluetooth.

After several tests, the only major difference I found was the volume. I had to adjust the Bluetooth volume up each time I paired it, which is an apparent “feature” on my phone designed to make sure people don’t damage their ears. Unfortunately, without access to some professional audio measurement gear, the scope of my audio testing ended here with a subjective opinion. It sounds nearly as good as a cell phone’s headphone output, with that cell phone being my Motorola Z2 Force. I’m positive that with higher-end equipment, there would be some variation between the original audio and the output, but with mid-ranged audio gear, I doubt anyone would be able to tell.

Range and Idiosyncrasies

The last few things I want to cover are pretty straight-forward. I tested the range of the device, which lived up to the 10 meter (33 feet) claim. I walked 40 feet away from my car with the phone and it did not disconnect.

There are two other things I wanted to cover with this Bluetooth adapter. This device does not have a microphone. While this is in the description for the device, I think it’s worth pointing out. When you answer an incoming phone call, it pauses your music and the sound goes through the phone. So for that, I’m thinking this more appropriate for your home and not your car, since most states have some kind of hands-free law at this point. The other thing I found is the device shuts off when you plug the microUSB charging cable into it. Unplugging it while listening to music does not do this, however plugging it in does, which I found a bit strange.

Conclusions

I’ve been using this in my car over the past two weeks and I’ve been very happy with the sound quality so far. For around $25, I think this is a solid option if you want to wirelessly play your music to a sound system or use Bluetooth headphones with your TV. If you are looking for a hands-free device for your car, this probably isn’t for you. However, if you are interested in playing music through your car, it will handle that perfectly well.

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