Product Review: Grom Audio USB2

I have a 2007 base Prius. The stock radio (51830) has no AUX input nor can it play MP3 disks like the next higher level non-JBL radio (51824) found on some 06 - 09 packages. I briefly installed a used 51824 but had to run my own AUX wiring and was disappointed the MFD did not support the radio (no text whatsoever). I returned the 51824 due to a defect and re-installed the original.

After reading about many options for adding AUX and iPod integration on this site I decided to purchase a Grom USB2 from Grom Audio and become an acceptance tester. The device iteself cost about $125 plus shipping and I am supposed to receive $60 back at some point for being a tester. By the way Grom Audio has not previewed this review nor made any suggestions about what I write. OK now that the disclaimer is over lets move on.

The USB2 connects to the CD changer port on the radio and is slated to have three main features for audio input: AUX, USB (mainly via memory stick but other methods work), and iPod. I say slated because as of right now only AUX and USB inputs function. iPod integration is scheduled to be released by the end of June 09. Functionality upgrade is accomplished via firmware which I have done twice so far and works well by download onto a memory stick. To review the full list of features of USB2 please go to gromaudio.com.

The USB2 comes with the device itself, a Toyota specific cable, and two 6 ft cables - one for AUX (3.5 mm stereo M/M) and one for USB (2.0 M/F). It also comes with a 256 MB USB memory stick and a user manual. I dont know the exact dimensions of the device but I posted photos so you can see the relative size.

Installation was relatively easy. I opted to remove the radio instead of trying to install it by just removing the glove box and the vent panel to its left. My installation philosophy was to try to install the device and the wiring right on the radio itself. That way once the radio was re-installed the USB2 wiring would already be complete. I attached the USB2 to the rear of the plastic tray below the radio using velcro strips. See the first photo below. In order to fit back into the dash the USB2 has to be located close to the heat sink on the radio. If you try this method be sure to leave some space between the USB2 and the heat sink so the former does not take on heat and the latter can do its job. With the USB2 in place on the plastic tray I ran the Toyota specific cable into the CD changer port on the back of the radio. I then drilled a hole in the side of the plastic tray and ran in the AUX and USB wires leaving just enough room in the tray to connect the jacks (see the 2nd photo). I secured both wires to the tray frame with plastic wire ties. Because 6 ft cables were supplied I had to coil them up and tie them off with wire ties behind the radio. I will eventually swap them for shorter cables so there is less clutter behind the radio. With this done I simply re-installed the radio and closed up the dash.

When I first powered up the car and pressed the disk button the radio recognized the USB2. However while testing it over the next several weeks there were a couple of times when the USB2 was not recognized. Restarting the car fixed it. I reported this to Grom and was told that this is being addressed in firmware. This has not happened to me with the latest firmware release.

I tested the AUX input with my wife's iPod Nano. It worked well and sounded like the AUX in my 07 Camry LE. I do not have a 12 volt power cable for the Nano so I could not test it to see if any hum is present as has been reported for the AUX on certain Prius models. I will try to borrow a cable and test it when I can.

To switch from AUX to USB and vice-versa press any other audio mode button (i.e. AM, FM) and then press Disk again within 2 secs. I can even press the mode button on the steering wheel 4 times rapdily to do this. While in USB mode pressing the audio switch on the MFD brings up the CD Changer screen (see the 3rd photo). The main (root level) folders in the memory stick are mapped to vitrual disks 1 thru 6. You can have more main level folders but you have to press and hold the ^ button on the steering wheel to get to them (you can get to them from the radio/MFD also). Each press of ^ with a beep moves you up a folder so you can theoretically have 99 main folders with only the first 6 being mapped to its own button. I tried only a few folders past 6 and it worked well.

I tested the memory stick with MP3 and unprotected ACC (iTunes) files and they worked well. The sound was very good - about what you expect from an MP3 disk. In my opinion USB memory sticks are much easier to work with than creating MP3 disks as you simply drag and drop files on it. Plus the USB2 can address 32 GB of memory which is a whole lot more than a data CD. The USB2 also supports WMA and OGG formats but I didn't try these.

One caveat I noted was that if you are playing from AUX (say an iPod) and you switch to USB, you can still hear the AUX faintly.
I asked about this and was told to simply disconnect or turn off the AUX device. They are considering whether to improve input isolation on the unit. I dont see this as a big deal but just thought I would pass along what I found.

I am pleased with the USB2 so far and look forward to testing the iPod integration when it becomes available. One last note: the USB2 does not support Artist / Track information yet on the MFD. I am told this will be available when iPod intergration is enabled. I should also mention that Grom Audio has been very responsive to my emails, always answering with 24 hours. If anyone has questions about installation or useage I'll do my best to answer them or to find out. Thanks.

 

I cant recall trying to use the CD player since I installed the USB2 so I just went out and tried it and - yes, it works. If someone has an external CD changer plugged into the radio's CD changer port, you will have to disconnect it to install the USB2. In other words you will not be able to use the external changer anymore. The CD player built into the radio should work fine, as mine does.

 

You are describing the base Prius radio which is just like mine (look for the number 51830 on the faceplate). Yes, it has a CD changer port on the back. If you just want AUX-in Grom has a product for that which according to gromaudio.com costs about $60. Good luck with your project.

 

Thanks for sharing your experience. After reading your post I contacted Grom and asked if they still intend to add iPod integration. They said it is still in the works and the firmware to support it would be released in a few weeks.

 

I do have 4 of those wires I can give you. PM with your address and I'll mail them out.