Music Player Network Home Guitar Player Magazine Keyboard Magazine Bass Player Magazine EQ Magazine
Topic Options
#1039731 - 02/15/06 10:18 PM Balanced and Unbalanced Line Question?
gaotu Offline
Senior Member

Registered: 01/10/04
Posts: 211
Loc: Indianapolis
So I was teaching a high school class today and up came the topic of balanced and unbalanced cables. I found that I was a bit confused. Here's my dilemma:

unbalanced and -10db go hand in hand
balanced and +4db go hand in hand

What does that mean - and technically, which source is louder, a balanced or unbalanced source?

The teacher of the class (the class was on a field trip to my studio) said that in his experience line level sources always seemed louder. I can't say that I've had this experience - it doesn't seem to make any difference either way, no matter if I'm using the Trim on my mixer or pluging something into my unbalanced/balanced accepting compressor. Hmmmm

Secondly, I read in an article while trying to research this that if you are beginning with an unbalanced source that you shouldn't interject a balanced cable into the signal path. According to this article it introduces noise and other problems. Oddly enough, I do this all the time and I've never had any problems. I frequently plug keyboards or even my insert signals (from my mixer) into my balanced patchbay where it travels to either a balanced or unbalanced process (depending on my choice of the moment) and back out again thru the balanced patchbay into my mixer - where, if it's going back to an insert, it's unbalanced. I've never experienced any anamolous noise. Am I just lucky? What do you experts make of this?
_________________________
http://www.myspace.com/anchorrecordings

Top
#1039732 - 02/16/06 10:26 AM Re: Balanced and Unbalanced Line Question?
paully Offline
Platinum Member

Registered: 05/25/04
Posts: 1129
Loc: Northern New Jersey
..unbalanced and -10db go hand in hand
balanced and +4db go hand in hand..
What does that mean - and technically, which source is louder, a balanced or unbalanced source?
>>>>>>>>>>>>>>>>
Differentiating loudness between bal vs. Ubal is not an issue.. just a way of connecting. A balanced XLR mic is not necessarilly hotter than an unbalanced guitar signal. Without getting overly wordie or technical, -10 and +4 are industry standards of design, so that input impedance/output voltages will match up predictably 'out of the box'. They are voltages available into a specified load resistance. Into a contant load, +4 is a much higher(hotter) level. Volume is ultimately a function of voltage. Ergo, into a constant input impedance, +4 yields the higher volume and lower noise floor.. sometimes too much volume, requiring padding.

The teacher of the class (the class was on a field trip to my studio) said that in his experience line level sources always seemed louder...
>>>>>>>>>>>>>>>>>>>>
Into a constant load impedance, you should hear a sugnificant difference in volume from -10dB.

Secondly, I read in an article while trying to research this that if you are beginning with an unbalanced source that you shouldn't interject a balanced cable into the signal path. According to this article it introduces noise and other problems. Oddly enough, I do this all the time and I've never had any problems.
>>>>>>>>>>>>>>>>>>>>
Ditto.

I frequently plug keyboards or even my insert signals (from my mixer) into my balanced patchbay where it travels to either a balanced or unbalanced process (depending on my choice of the moment) and back out again thru the balanced patchbay into my mixer - where, if it's going back to an insert, it's unbalanced. I've never experienced any anamolous noise. Am I just lucky? What do you experts make of this?
>>>>>>>>>>>>>>>>>
Don't let anyone BS you. We all do this! You're just not using one leg of the patchbay jack. No big. As long as the bay uses the tip of the TRS as the hot leg(industry standard), you're in business.

Paul
_________________________
WUDAYAKNOW.. For the first time in my life, I'm wrong again!!

Top
#1039733 - 02/16/06 03:20 PM Re: Balanced and Unbalanced Line Question?
Bill@Welcome Home Studios Offline
MP Hall of Fame Member

Registered: 08/23/03
Posts: 9613
also, +4 is on one scale, and -10 is on another... they do not equate, they are not comparable (without conversion), and there is not a 14dB difference between the two.

Balanced is three wire +, -, and screen or ground. unbalanced has the - and the ground bonded.

When you plug anunbalanced item into a balanced signal path, you unbalance the entire path. (until you go through a device that is capable of rebalancing the signal.)

Balanced is generally quieter because of something called common mode rejection. Much noise is constant. If it is coming in both on the + and - wires, it is out of phase with itself, and cancels itself out.

Bill
_________________________
"I believe that entertainment can aspire to be art, and can become art, but if you set out to make art you're an idiot."

Steve Martin

Show business: we're all here because we're not all there.


Top
#1039734 - 02/16/06 07:55 PM Re: Balanced and Unbalanced Line Question?
miroslav Offline
Cosmic Cowboy
10k Club

Registered: 05/23/00
Posts: 14215
Loc: NY Hudson Valley, USA
Yeah...I try to preserve the balanced/unbalanced path when I can.
I have 18 channels worth of Bal-->Unbal or Unbal-->Bal conversion capabilities...
...but as things go in to studio...there are many times I just connect as I go...and if the signal stays clean...I don't sweat it if I don't use trannys.

With the +4/-10....you have to watch the signal so as not to overdrive or starve your inputs...but I've gone +4 into -10...or -10 into +4...and if the signal stay clean with a pad or a boost...I don't let it worry me too much.

On may patch bays...for the gear that offers both...I actually ran patch points for both.
That way I just use the correct patch points as needed.
Of course there is some gear that just has on or the other...so, I try it out...and if it's good, I let it go...if I see some problems with the signal, I'll use the trannys to make the conversion as needed.
_________________________
miroslav - miroslavmusic.com

"Just because it happened to you, it doesn't mean it's important."

Top
#1039735 - 02/16/06 10:23 PM Re: Balanced and Unbalanced Line Question?
gaotu Offline
Senior Member

Registered: 01/10/04
Posts: 211
Loc: Indianapolis
Thanks for the pointers everyone!
_________________________
http://www.myspace.com/anchorrecordings

Top