Thread: Mixing down 2 sources into 1

I've got an iPod and a GPS to hook into the car stereo.

I had this same issue, and it's pretty easy to build one yourself. You just have to make sure each input has a resistor in-line with it. Take a look at the schematic here. You just have to wire that together for both left and right. That circuit doesn't have any level adjustment, which is often not a problem, as you can adjust the output level on the devices themselves. If it is an issue, though, there's another circuit that includes potentiometers to allow basic mixing.

Then you probably just want an audio jack Y cable that lets you connect 2 inputs at the same time.
[media]http://img.alibaba.com/photo/205180948/3_5mm_PLUG_MALE_TO_2_JACK_FEMALE_Y_CABLE_STEREO_AU DIO.jpg[/media]

You can hook both up and they will work fine, if you play them both at the same time it will play them over your stereo at the same time too.

Originally Posted by shatteredzman

Then you probably just want an audio jack Y cable that lets you connect 2 inputs at the same time.

You can hook both up and they will work fine, if you play them both at the same time it will play them over your stereo at the same time too.

You definitely don't want to do that. Each device tries to force the other device to a different voltage, and it can ruin the output of the devices.

Except you want 4 RCAs to 2. Two of these:


Put the two lefts on one and the two rights on another Y-adapter and then plug the two adapters into the RCA's you have available.

Originally Posted by HyperZulu

Except you want 4 RCAs to 2. Two of these:


Put the two lefts on one and the two rights on another Y-adapter and then plug the two adapters into the RCA's you have available.

I thought ipods used audio jacks? I dont know because I dont own one. But if it uses an audio jack you can get an rca adapter. All the adapters listed so far come in different combinations of male/female ends so get the one that is the easiest to use.

[media]http://www.rueducommerce.fr/hifi/images/produits/info/xl/HRCA.jpg[/media]
[media]http://img.alibaba.com/photo/205246107/3_5mm_1_8_Female_Mini_Jack_to_2_RCA_Plugs_Audio_Ca ble.jpg[/media]
[media]http://www.usbcables.com.cn/Upload/product/200681622264822955.jpg[/media]

Basically, you can mix them by directly connecting them together (preferably through small capacitors).

As the guy below mentioned, you may need to tweak levels though, with
resistors. So its a sub-optimal solution. You could design a more complex
circuit.

However, also, chances are if the two inputs happen to be (say)
an MP3 player and a handsfree speakerphone, then you may want to
drop the volume slightly on the music when the handsfree speakerphone
kicks in.

For that, you need a more complex circuit. But, believe it or not, you can
still use relays to achieve all this, in a quick but effective method.

Here is the diagram: [media]http://home.btconnect.com/shabaz/misc/audiomixing.jpg[/media]
(it only shows one channel e.g. left, you need to repeat it for the right channel using the other half of the DPDT relay).

When the relay is not energised, then most of the volume is from the MP3 player (some slight leakage of sound from the phone, but unlikely since there is no phone call yet). When the phone rings, you need to arrange for the phone kit to activate the relay. This will switch most of the phone volume to the output, and a reduced level of music. There are other ways of doing it, but this is a quick idea.