[sdiy] stereo output questions.....

[Graham Atkins]

Jure,

You are wrong. A TRS jack is defined as a 3 circuit connector carrying
balanced audio.

Graham

On 27 Nov 2008, at 16:48, jure zitnik wrote:

> since he wrote "2 XLR cables", he obviously means balanced stereo.
>
> again, when you say TRS, what exactly do you mean? "TRS" does not
> describe a signal, it merely describes the mechanical connector. so if
> you take the 6.3mm jack (male) connector with 3 contacts an look at
> it:
> T(ip) - the end of the jack
> R(ing) - the middle section
> S(leeve) - the rest, this contacts is the biggest
>
> the other 3-contact mechanical connector is called XLR, again, it's
> just a name for the connector, meant to fit on a 3-conductor (3 wire)
> cable.
>
> now you can use those 3 contacts - on a TRS or an XLR connector - and
> the corresponding 3 conductors in the cable for different purposes,
> but mostly the following two:
>
> 1. unbalanced stereo audio - usually TRS is used for this, i don't
> think i've ever seen XLR used for stereo.
> the TIP and the RING contacts are used for left and right audio
> signal, the SLEEVE is used as ground for both. that way you get a
> stereo signal on 3 conductor cable, with TRS jacks.
>
> 2. balanced mono audio - both TRS and XLR are commonly used here, but
> TRS are usually used in studio. they are less bulky but also less
> durable. on stage, you'll usually see XLR.
> the idea of balanced audio is to use two "copies" of signal, using two
> separate conductors, to eliminate the noise that is common to both
> copies. the general idea is to send the signal and an inverted copy of
> the same signal. then at the receiving end the inverted copy is
> inverted again and the copies are added together, but the common noise
> between the two subtracts (because of inversion). so at the end you
> get the signal twice the amplitude, minus the noise. for this, you
> again need 3 conductors. one for the original signal ("hot"), one for
> the inverted one ("cold") and again one ground for both together.
>
> so, which one do you need, the question is not "TRS or stereo". the
> question should be first "stereo or mono", then "balanced or
> unbalanced", and then "XLR or TRS".
>
> On Thu, Nov 27, 2008 at 3:51 PM, John Mahoney <jmahoney at gate.net>  
> wrote:
>> Here are 2 ways to carry stereo signals:
>>
>> 1) A pair of 2-conductor cables, one for L and one for R. Each  
>> cable has a
>> hot (signal) line and a ground.
>> 2) One 3-conductor cable, with a hot line for L, a hot for R, and a  
>> common
>> ground.
>>
>> 3-conductor stereo cables typically have TRS connectors. Example:
>> headphones.
>>
>> However, TRS connectors are also used for mono, balanced cabling,  
>> which also
>> has 3 wires (signal+, signal-, and ground).
>>
>> XLR connectors can carry stereo signals but they are usually used for
>> balanced mono.
>>
>> When you say "stereo not TRS", do you mean separate Left and Right  
>> cables
>> instead of one stereo cable?
>>
>> John
>>
>>
>> At 08:47 AM 11/27/2008, Dan Snazelle wrote:
>>
>>> no i think i mean just plain stereo..not trs
>>>
>>> the guy wants to convert a stereo signal (left and right) into an  
>>> adapter
>>> that goes into 2 XLR cables...
>>> i was pretty sure he said STEREO not TRS but he might not know the
>>> difference.
>>>
>>> so basically if i send an inverted signal to one side and a normal  
>>> to the
>>> other, that is TRS?
>>>
>>> thanks
>>
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