IMAC i7 to 5.1 surround

[jmunzke]

I have an iMac i7 and an old Sherwood 4 channel analog power amp (2 RCA jacks in and 4 channels out). I was hoping to use the MIDI interface on the iMac to make my iMac a pre-amp and power my speakers with the power amp.

So far no luck.

I have a Y cable from the headphone on the iMac to the RCA's on the power amp. I can get stereo but no 5.1

THE QUESTION: How can I use my imac to play 5.1 with my amp provided the power to the speakers.

(there is no optical in on the receiver, only RCA in.)

 

[blueroom]

What is the model number of your current amp?

You need an amp with a Dolby 5.1 decoder. They'll usually have an optical input.

 

[jmunzke]

What is the model number of your current amp?

You need an amp with a Dolby 5.1 decoder. They'll usually have an optical input.

" old Sherwood 4 channel analog power amp (2 RCA jacks in and 4 channels out)"

Is there anyway to use the existing sound card in the iMac? Or is there an existing mac compatible sound card that will process the sound into 5.1

 

[blueroom]

Nope. It's a two channel amp. You need to buy an A/V receiver.

 

[Makosuke]

I'm assuming from your description that the amp you have is using Dolby Pro Logic to extract a 4.0 soundstage from stereo audio. In which case, so far as I know, the connection setup you're describing should work--the multichannel should be part of the actual audio, and would be passed out via the analog signal. Sure it's not something in the software chain (I'm not fully understanding what you're describing on the other end) doing it?

I'm mostly responding because I know for a fact this works with stereo audio (from a lossy ripped CD) output via the optical output; if I set the receiver to Dolby Pro Logic mode, it will correctly extract the lo-fi surround channel from CDs that have it. I haven't actually tested with a pure analog out, but I'm pretty sure it'd be the same.

 

[blueroom]

Dolby Pro Logic is not DD5.1, not even close.

Pro Logic attempts to make a rear channel from stereo. DD5.1 is five speakers (Left, Right, Center, Rear L/R) and subwoofer.

An A/V receiver isn't that expensive and has the Dolby decoder you need. It's good speakers that'll put you in the poor house.

If you're just listening to music from CD or MP3's then two channel is fine and for most folks preferred (the extra channels are not part of the original material).

 

[jmunzke]

Thanks for the input, yes, I have an old 80's audiophile 45 lb stereo amplifier. I was hoping the Imac would work as a pre-amp and my Sherwood amplifier would just boost the signal. In retrospect, the question was probably a bit naive. I have run 5.1 with my tv (and an AV setup). I was just hoping to run 5.1 with this spare amp.
Sounds like that can't be done.

Dolby Pro Logic is not DD5.1, not even close.

Pro Logic attempts to make a rear channel from stereo. DD5.1 is five speakers (Left, Right, Center, Rear L/R) and subwoofer.

An A/V receiver isn't that expensive and has the Dolby decoder you need. It's good speakers that'll put you in the poor house.