Newsgroups: rec.audio.tech Subject: Re: Connecting subwoofer with speaker wire References: <[email protected]> [email protected] writes: > I have a room which I attempted to pre-wire for home theater. There is > a regular speaker wire behind the wall which I intended to use for the > subwoofer. Now that I have the equipment, I realize that the receiver > has an RCA type subwoofer output only. That's typical on modern systems. You should have expected it in the beginning. > Since I did not have the > foresight to run a shielded cable behind the wall, I'm wondering what > will happen if I just solder RCA connectors to each end of the speaker > wire to make the subwoofer connection. If you just solder the RCA connectors to the speaker wire ends, you will get the sound going from receiver to subwoofer. But because the wires is not shielded, this wire will very easily pick up all kinds of interference starting from mains frequency humming pickup (50Hz or 60 Hz and the harmonics if it) anding to pickung noise from electrical (clicks when lights/equipment are switched on/off) and radio frequency interference (noise from nearby cellular phone etc..). You can try the connection and find out. The best approach to correct the problem is to wire right type of cable in place of the existing wire. If you have wired your cable to installation tube, relacing the wiring with a new one should not be too hard (use old speaker wire to pull in new wire or wires). If you need to use the existing wire and the noise is a problem, then one approach would be to use a balanced line approach: Convert the signal to the balanced in the receiver end (audio transformer, professional distribution amplifier, small mixer etc) then using blaanced received on the subwoofer end (XLR connector if it has those, through audio transformer to RCA, usign small mixer with balanced inputs etc..). Balanced line signals will travel acceptably even through unshielded wires. Balancing is the trick. Another idea if your subwoofer has speaker level sound inputs: Put a small audio power amplifier between your receiver RCA output and the speaker wire on the wall. This will convert the signal to strong speaker line signal that will survive in the noisy enviroment in unshielded cable (the toughness has to do with the stronger signal level and lower output impedance compared to line level signal). The at the subwoofer end kust wire the signal to "speaker level" input of the subwoofer instead of that RCA input. If your subwoofer does not have "speaker level" inputs, you can try car audio "speaker to line" adapter. -- Tomi Engdahl (http://www.iki.fi/then/) Take a look at my electronics web links and documents at http://www.epanorama.net/
