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Thread ID: 80227 2007-06-15 12:53:00 Mixing audio... Adamnz (12260) Press F1
Post ID Timestamp Content User
559625 2007-06-21 11:49:00 Yes, Thank you very much :) Adamnz (12260)
559626 2007-06-21 21:22:00 If you want a quick crude fix, 2 guitar leads fitted with smaller jack heads at each end, line out on both PC's to a 2 to 1 jack, straight into your source.

Ensure your volume settings are low to start off with then adjust accordingly.

Very crude but works.:2cents:
rob_on_guitar (4196)
559627 2007-06-22 04:10:00 Supertrouper has described a simple mixer. Although it will reduce the output, and is "theoretically" bad because it is mismatched , it will certainly work, probably very well. :cool:

Rob_on_guitar has described the worst possible way to "mix" two outputs. "Crude", yes, "quick", yes, "fix" NO. :groan:
Graham L (2)
559628 2007-06-22 07:45:00 Thanks ALOT supertrouper -
tinyurl.com

IOU1:thumbs:
Adamnz (12260)
559629 2007-06-22 11:17:00 LOL... good stuff Adam. Nice little adaptor box you made there.

Graham is quite correct in saying that it is 'theoretically' bad because it is mismatched - it is VERY mismatched - but it is the easiest, cheapest and most appropriate solution to mixing two or more sources in this situation.

Anything more and you simply end up re-inventing the wheel by building something that closely resembles a commercial mixer.
supertrouper (6665)
559630 2007-06-22 11:20:00 Could you explain VERY simply how it works :P ? Adamnz (12260)
559631 2007-06-22 11:24:00 Sure. Electricity goes in one end and comes out the other.

You did say "very simply" :D
supertrouper (6665)
559632 2007-06-22 11:28:00 lol, ok slightly more advanced...... Adamnz (12260)
559633 2007-06-22 11:53:00 Sorry, I have a warped sense of humour :lol:

Right, I will try to explain it in layman's terms .

Ok, the output of a sound source - amplifier, sound card, cassette deck etc has, in simple terms, a "resistance to ground" .

So, while the output is sending out a signal, if you were to look back up the pipe so to speak, you would effectively see a 'resistance' to ground .

This is called output impedance . I won't go into why it's there or how it's there, it just is .

Any resistance to ground will lower the level of your signal . The less resistance you have, the lower the signal will get . A dead short obviously gives you NO signal .

Now, your second source also has an output impedance .

If you connect your second source directly to the first one, the impedance (resistance to ground) of the first output will attenuate the level of the second output, and vice-versa .
Also, you have the two outputs fighting each other (because of complex reasons I won't go into) - suffice it to say they do .

By placing a resistor of a suitable value on the output of each source, then tying their other ends together, you now have a 'summing mixer' .

The resistors provide a degree of isolation of each source from the other one, and limit the amount of 'fighting' that goes on .

Because you have put more resistance in the circuit however, you do lose some signal . In an 'active' mixer, there would be one or more stages of amplification AFTER these resistors, to bring the levels back up to where they were BEFORE the mixing took place .

Here endeth audio lesson 1 . 01 :)
supertrouper (6665)
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