5.1 speakers to audio interface

[alesandar]

Hey, guys. That's my first thread in the forum, don't bite me.

I want to connect my old 5.1 sound system (Logitech X-540, which is not the best for the job, I know) to my new audio interface (Focusrite Scarlett 2i2). Seems like a classic story for now.

Well, I've three 3.5 male jacks from my sub (green - front; black - rear; orange - sub/center). If I connect two of them (nevermind if it's the green one and the black or the green and the orange, using mini jack to TRS connectors) to my line ouputs (left/right) of the audio interface, I can't hear any sub. If I connect just the green one to my headphone out, eveything seems to work fine, but my friend told me (and I also read hear and there) that this won't be a good idea, 'cause the headphone out could warm-up too much or something like that.

I just don't want my Scarlett to blow-up, so could you tell me what's your opinion? Is it really safety to connect the speakers in the headphone out? I read a lot of topics, but just want to be really sure.

 

[mjbphotos]

First - stop listening to your friend. "the headphone out could warm up too much"

Your 3.5mm male PLUGS (jacks are female) are stereo plugs, with a left, right and common. That's why it works when you plug it into your headphone jack, which is also stereo.
The TRS connectors on your Scarlett are balanced mono jacks, so if you hook up an adapter (3.5mm to 1/4" TRS_ you are only going to get one channel/side - in the case of using your orange connectore, you got the center speaker and not the sub.
You could take the green 3.5, use a splitter to go to 2 (left and right) 3.5mm mono plugs (or straight to 1/4") to plug into the two TRS monitor outputs, or just continue to use the headphone jack. You coudl mickymouse all the 5.1 jacks to hook up somehow to the Scarlett, but what's the point? The Scarlett has left and right ("stereo") outputs, not 5.1.

 

[Steenamaroo]

+1.
For proper discreet 5.1 you'd need an interface with 6 discreet outputs and a source capable of feeding them all.
In the ideal world, for your setup, those would be spread across 3 unbalanced stereo outputs.
In the real world it'll be 6 balanced line outputs.

For mock-surround, carry on doing what you're doing, or as mjb suggests.

 

[BroKen_H]

True that. You'll never get 5.1, but you can cobble two TRS outputs into one stereo output, then split the signal to power all three jacks, or just splice the three left hots together, the three right hots together, and the three neutrals together into one 1/4" TRS jack and run out of the headphone (that would be easiest).

 

[BroKen_H]

Or, like Steen alluded to, you could purchase an Avid MBox Pro or Apogee Quartet (or similar devices) that support 5.1 output.

 

[Steenamaroo]

I want to connect my old 5.1 sound system (Logitech X-540, which is not the best for the job, I know) to my new audio interface (Focusrite Scarlett 2i2). Seems like a classic story for now.

What's your goal?
Watching movies/mixing in proper 5.1 or just to have your stereo source coming out of all speakers?

If you're trying to go discreet there are plenty of fairly cheap units which would give you true 5.1 outputs over 3 jacks.
Most modern motherboards actually have them built in.
A long time ago I used a creative extigy usb "interface" for 5.1 movie watching.
The source was digital 5.1 output from a DVD player.
Your speaker jacks would plug straight into something like that.

 

[alesandar]

Thanks to all of you, guys. I didn't expected so fast replies.


@mjbphotos: About the warming up - well, I read the same somewhere in the web, people there has also said that it'll never be a good idea to connect speakers through headphone out of audio interface. And sorry if it's a mistake to call the plugs - jacks, but in my country, we use the word "jack" for both of the types.

@Steenamaroo: I doesn't really need the proper 5.1 system, just the stereo source and some better low frequency response. My speakers doesn't really support low frequencies, but the sub helps me out somehow. When it was plugged in the headphone out, I needed to turn both of the volume controls (of the speakers and the audio interface) really high, so I could be able to hear what's going on down there in my bass. That's the reason my friend said that about the warming up - he actually said that I shouldn't get the volume control of the headphone out more than 50% (which seemed to be too low for my sub).


Later I'll definitely try to get a splitter.

Thank you for your time, guys! Cheers!