anything wrong with hooking up xm AND radio to same line-in?

Sonicxtacy02 · 01-14-2008, 12:00 PM

i've run into a little snag with my set up. I have one line-in port on my SB Live! thats currently hooked up to my hd radio tuner. I now have xm and thought i could hook that to the mic-in. Mic Ind only works if nothing is plugged into line-in. So my question is is it ok to hook both the hd radio tuner and the xm tuner to the same audio line via a splitter. I'm worried about the voltage running back basically. The HD tuner isnt powered when its not in use... but the xm line stays powered regardless.

krnpimpsta · 01-14-2008, 02:48 PM

Yes.. you need to either:
a) get something to either manually/automatically switch between input signals and output one signal into your sound card
b) get a mixer that will combine your two signals and output one signal

Sonicxtacy02 · 01-14-2008, 03:29 PM

Quote: Originally Posted by krnpimpsta

Yes.. you need to either:
a) get something to either manually/automatically switch between input signals and output one signal into your sound card
b) get a mixer that will combine your two signals and output one signal

a) I've never heard of a "switch" for a 3.5" jack and have spent quite a long time looking for one to no avail

b) define "mixer". You mean a piece of hardware?

FusionFanatic · 01-14-2008, 05:43 PM

Quote: Originally Posted by Sonicxtacy02

I've never heard of a "switch" for a 3.5" jack and have spent quite a long time looking for one to no avail

you'll never find anything for a 3.5" jack... that would be huge!

(soundcard/headphone jacks are 3.5mm or 1/8"

)

I have never seen one commercially made, but In theory it would be very simple to make. no electronics needed, just a standard DPDT switch, a 1/8" plug, two 1/8" jacks, and some wire... then just solder away! mount it in a small plastic project box to make it look nice

an alternative would be to use an audio input switch for RCA inputs. you would just need a few adapters to change the headphone plugs to RCA's. it wouldn't be as clean as making your own but the end result would be the same.

Quote: Originally Posted by Sonicxtacy02

define "mixer". You mean a piece of hardware?

yes, a mixer is hardware. it combines two inputs into one. basically it keeps the two signals from fighting with each other. the downside is that both signals will be attenuated. you can built a basic mixer yourself pretty cheap, but it's not really worth considering this option because you'll never be listening to both XM and HD/FM at the same time.

krnpimpsta · 01-14-2008, 05:55 PM

Haha, (mental picture of 3.5" jack)

Anyways, if you have cash to spend, a mixer (or a new sound card) would probably be the best idea, so you won't have to manually switch between signals every time you want to switch between XM and Mic.

I say mixer, not because you would want to receive both signals at once, but because it removes having to manually switch. Mixer scenarios:
1) One device is on, one device is off: Mixer receives 1 signal, mixes it with nothing. you get the 1 signal you were looking for.
2) Both devices are on (oops): Mixer combines both signals. Had you hard connected them with a Y-adapter, this scenario would have probably led to damage to the two components outputting a signal. (Then again, if one of the components is just a passive Mic, it may not be serious, or anything - but it's just not a good idea to combine the audio outputs of two devices by shorting with a wire)

Otherwise.. I agree with CompGeek - maybe you should look for an RCA signal selector and use adapters...

FusionFanatic · 01-14-2008, 07:05 PM

Quote: Originally Posted by krnpimpsta

Mixer scenarios:
One device is on, one device is off: Mixer receives 1 signal, mixes it with nothing. you get the 1 signal you were looking for.

that would be fine if it worked that way, but it doesn't...

the problem is the signal that comes out of the mixer is not the same as the signal that went in. a mixer is designed to mix two inputs together, to do this is has to attenuate each signal to keep the now combined signals from overloading the amplifier input. both signals are attenuated regardless of whether or not the other signal is on or off. to compensate for the signal loss, the amplifier would have to be turned up louder. the louder the amplifier has to be turned up to compensate for signal loss, the worse it will sound.

the other issue is that sonixtacy's XM signal is always on, whether it's being used or not. thias wouldn't be an issue when listening to XM, but both signals would be on when listening to HD (unless power to the XM tuner was cut). the only way to avoid this problem is to switch between inputs or cut power to the XM tuner when not in use (which would require a switch anyways). for these reasons a mixer is not a good option.

jontz · 01-14-2008, 07:54 PM

BOOM! Here you go!

http://electronicsusa.com/mk1and2.html

krnpimpsta · 01-14-2008, 08:40 PM

CG - you're right, good point.

PaulF · 01-14-2008, 08:45 PM

What I did to overcome a similar situation is use an RCA A/B switch and use adapters to convert the RCA jacks to 3.5mm jacks. Worked like a charm.

Sonicxtacy02 · 01-15-2008, 09:56 AM

so here's my plan.. lemme know if this sounds feasible. I plan on purchasing a system selector with IR remote.. and using my usb IR transmitter/receiver, i will transmit the switch command (via girder) to the system selector. I should be able to make road runner send the command to girder as a part of the "XM" and "RADIO" commands using the exectbl.ini. Does this sound feasible? I've never set up girder to transmit ir signals only receive them.. but being that the usb IR i have says it receives AND transmits it should just be a matter of adding some girder code.

jontz · 01-15-2008, 05:11 PM

I don't see any reason why that wouldn't work...but that's the last time I scour the net to find you a switchbox since you aren't even going to use it

FusionFanatic · 01-15-2008, 06:47 PM

it sounds feasible, but it also sounds like more work than it's worth...

it would be easier to just get the switch box jontz linked to (BTW, nice find jontz

). you could mount it to the side of your center console, or wire a new switch to it to mount somewhere on your dash, console, etc.

good luck