Bluetooth HiFi Audio Output (that works)

[mikealder]

A goal of mine for some time has been audio quality from the TomTom 720 while in the car playing mp3 audio. The inbuilt FM transmitter is fine until I venture near a major city at which point it is difficult to find a free frequency. The line out option is great, but it requires a stereo that has the necessary socket, and involves more wires strewn across the dash, it can also suffer from “Ground loop interference”

The Go-x10 and x20 devices all support audio out via Bluetooth, but this has (until now been very costly to get working). Enter the LG LAC7700R, ok it isn’t going to win prizes for being particularly nice to look at, but it does support Bluetooth A2DP. In addition it is a breeze to set up and connect to the TomTom products that support Bluetooth HiFi Audio output (all x10/ x20 devices).



At a price of only £124:99 this DIN sized device isn’t going to break the bank. But as my old Kenwood died recently, this was going to fit the requirement quite nicely.

A trip to the local Halfords with the TomTom devices in my pocket was undertaken, when I asked about TomTom Bluetooth audio support “it simply cannot be done, the device doesn’t support it, use the FM transmitter” was the reply. I carried on messing around with the 720 in store and got the TomTom connected and it worked.

They had the last laugh though as there were non in stock other than the demo unit!
I got the head unit from the Preston branch, ten minutes to fit (the car was already equipped with the correct connectors and mounting frame left over from the dead Kenwood).

In use the audio quality is simply fantastic, it knocks spots off the FM Tx or even a cabled connection, although the volume level is a little on the low side. Crank up the volume on the head unit and all is well, but you do get a shock if you switch back to CD or radio without turning it down first.

The TomTom will maintain the Bluetooth connection to the head unit even while making a hands free phone call, sadly the phone audio is only routed through the TomTom’s speaker. In use I am very impressed with the new capabilities this deck has to offer, if you want the best audio output in way of quality Bluetooth is the way to go, for once it doesn’t cost the earth. It also sports a 3,5MM audio socket on the front panel, so a wired connection is possible, but why bother when the BT Audio is so clear.



The above picture shows the deck in BT Audio mode, paired to the Go-720.

Their advert doesn't lead you to the fact the device works with a TomTom in this way, see Here but take your x10/ x20 to the shop and have a play (the pair code for the LG is 1234, otherwise follow the prompts from the speaker preferences menu - Mike

[AndyVaughan]

Nice one Mike!

I like the custom mount as well - have you drilled through it for the RDS-TMC?

Andy

[mikealder]

[AndyVaughan]

Yep - a post that slipped me by!

RDS-TMC working fine for me now on the 66 since I hard wired in to the aerial - on 7.221 anyway. Haven't a clue what is going off on 7.480!

Andy

[dizzyfergy]

Try any of the sony blue tooth models MEX-BT2500 , 2600 or 3600 ,much nicer looking than the LG. The 2500 is on flea bay for around £75 as its a discontinued model.

[mikealder]

I did try the 2500, but the TomTom couldn't find the unit, so I chose this one as it worked - Mike

[kattt]

I also tried the 2500 at Halfords a few weeks ago, and TT couldn't find it at all. It only found the LG LAC7700R, so I held down the pair button, told the TT to connect, turn the volume up on the LG, and voila, the store was subjected to some Trans-Siberian Orchestra.

Therefore, I can confirm that the MEX-BT2500 doesn't work at all with TomTom, and the LAC7700R works very well. I got my 7700R from Ebay for £55 including all accessories and DIN bracket, alas the plastic fascia trim edge thingy had three broken "clamps"/notches, but it stays where it is.

It's fairly easy to solder the end of the RDS-TMC aerial to the FM aerial. I soldered it to the aerial on the aerial's PCB connection point, and it's just small enough to exit from between the PCB and the bottom of the unit where the RCA connectors are.

If you look carefully underneath the unit, you can see three solder points for USB 5v, but alas they are never actually powered up If you want to take it apart for access to the PCB, the huge CD cage can be removed - it's connected to the PCB with a ribbon cable which can be easily removed and inserted again. It also powers back up and works just fine - the SRC button just ignores CD completely.

It's also fairly simple to connect a car radio to a PC ATX power supply. Connect the ignition (and battery? I did.) wires from the radio to a yellow +12V wire on the PSU, and GROUND to the nextdoor black.

Then solder or jump the green and ground wires as shown here:
http://modtown.co.uk/mt/article2.php?id=psumod

To do a nicer job, use heatshrink. Black electrical tape is a bit yucky.

It might be possible to solder the FM antenna to the radio's front connector strip and cut the PCB track so that you can hook up the RDS-TMC cable to the aux input... I've checked with my multimeter and the aux input connector end tip (left audio signal) has a resistance of 1.2kohms (balanced input?? I know nothing about audio) with the third pin from the right on the block of gold connectors. I dunno what 1.2kohms would do to the FM signal.

edit: there's one on ebay right now: 120238056975

[dizzyfergy]

Hi, how did you try pairing the 2500 with the tomtom .The sony unit should be switched off before trying to pair a new device. If the head unit is switched on it wont work.

[mikealder]

As the Sony was my preferred choice, I downloaded the manual, printed the relevant pages and followed the instructions in the shop, The TomTom never presented the Sony for selection. I am quite happy with the LG it connects and works very well with the TomTom, all the other units I have previously got to work cost in excess of 350 - Mike

[weelogic]

Can anyone provide an idiot's guide to getting the Sony BT2500 working with the 920? I have gone into the 920's settings for speakers and it has gone off searching for Bluetooth hi-fis (while the BT2500 is in discoverable mode) but it never finds it! It's driving me nuts, as this would be the perfect solution to my wires problem...

[mikealder]

I suspect the Sony doesn't have the same Bluetooth support that the LG has available to it which is why it doesn’t work with the TomTom devices, just because it says Bluetooth on the device doesn't guarantee compatibility - Mike

[AndyVaughan]

After experiencing this first hand in Mikes car, the sound quality is sooo much better that the FM transmitter - silence is actually silence, and the dynamic range is significantly better.

I am sorely tempted to buy one - shame it isn't as good looking as the Sony . . . ..

Andy

[weelogic]

Mike, is there a built-in microphone in the LG unit? I have the BT2500 which is great for hands-free calls (much better than the GO920, since it doesn't output the calls and handles them all through the basic speaker). I would consider changing to the LG to access the bluetooth streaming from the 920, but only if it could handle calling functions at least as well as the Sony.

[mikealder]

There is an external microphone supplied with the LG, BUT if you have the TomTom playing music via Bluetooth and the phone paired to the TomTom all the calls will be handled by the TomTom.
There is something in the instructions about the LG switching BT devices, but as yet I have not tried pairing up the TT and the Phone to the LG at the same time, I will give this a try in the morning - Mike

[weelogic]

Thanks for the reply Mike. It would be interesting to see how it handles 2 BT devices at the same time.

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