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I have a pair of studio monitors that I want to set up. I'm connecting them to an Mbox2. The Mbox has 1/4" connectors for monitor out, but I have a choice on the inputs on the monitors; I can either do 1/4" or XLR in. Is there a difference in sound between the two inputs? Does it matter which way I go? Also, I'm a little confused about balanced vs unbalanced. The inputs can be either; does that matter?

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XLR is for balanced interconnects. As you will be sending an unbalanced signal from your Mbox, I doubt you would notice any improvement by using the XLR inputs on your monitors.
 

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Do you have the regular MBox 2? Or the MBox 2 Pro? If the former then your outputs are unbalanced, if the latter, then the outputs are 1/4" TRS balanced. The unbalanced outputs are one of the several ways that Digidesign botched up the design of the successor to the very popular MBox.

Either way, get a pair of these cables. These will work for both balanced and unbalanced 1/4" connections, since the sleeve portion of the 1/4" TRS will still correlate to the ground of the XLR, and the tip will correlate to Pin 2 of the XLR.

There is no difference in sound between a balanced XLR cable, and a balanced TRS cable, as long as they are wired correctly (i.e. pin 2 to tip, pin 3 to ring, and pin 1 to sleeve).

I prefer using XLR connections whenever possible. They lock into the connection, and because of their design they do not short while plugging them in because the pins are always kept seperate.

Edit: according to page 35 of the MBox 2 Getting Started Guide the MBox 2 1/4" moniotr outputs are balanced TRS connections.
 

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Balanced vs. Unbalanced cables

Balanced cables have a distinct advantage over unbalanced cables. Balanced cables are engineered for very low noise.

Essentially, a balanced cable has an extra wire as compared with an unbalanced cable. The signals in both types of cables are subject to pick up noise during their travels through the wires.

With unbalanced cable, any noise picked up by the cable becomes mixed with the signal.

With balanced cable, most noise picked up by the cable can be filtered out.

[Please see the post below for more info on how balanced cable works, and for a link to detailed information.]

To realize the full benefit of balanced cable, the equipment you use needs to feature balanced connections and the corresponding circuitry to minimize noise.
 

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Umm...no.

Balanced cables offer greater protections from interference by spliting the signal between the two signal wires, and using the difference between them to generate the signal. And by using a twisted pair configuration which reduces pick up of outside EMI.
 

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JCBigler said:
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I prefer using XLR connections whenever possible. They lock into the connection, and because of their design they do not short while plugging them in because the pins are always kept seperate.
....
Normally I'd agree, used them for years (decades) and been very happy -
and then I met The Cable From Hell.

TCFH had an XLR plug on one end, and a 240V UK mains plug on the other.
 

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DougR said:
TCFH had an XLR plug on one end, and a 240V UK mains plug on the other.
Yeah, I've heard about old power plugs using XLR connections (which incidentally come in more flavors than just three pin--I spent the summer making four, five, and a couple of six pin XLR cables, for moving light control). Some of the old movie projectors used to use XLR power, and the Midas Venus 320 uses a six-pin XLR power connector.

XLR, btw, stands for Cannon X series, Locking connector, with Rubber insert.
 

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An XLR cable has a ground cable and two runs of the audio signal waveform with opposite polarity in the two runs. The ground cable shields the other two.

Both audio signals pick up the same noise at the same polarity. At the other end of the cable, circuitry inverts one signal's polarity and sums the two signals. Since the signals are at the same polarity now and noise in one is at reverse polarity of the noise in the other, summing the signals cancels the noise. This works best with long runs of cable where more noise is generated.

Cables with XLR on one end and 1/4" phone plugs on the other are for convenience in matching plugs to jacks. These cables have no noise cancelling properties other than shielding. However, many devices expect high impedence at a phone jack and low impedence at an XLR, so signal strength might not be what you expect. Some microphones have XLR jacks and impedence selection switches and you would use such cables when the amp has only phone jacks. Some cables themselves include impedence matching transformers. It's best to know what you are working with.

I think I got most of this right. It's been a long time since I had to deal with it.
 

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Sort of. Like I said before, a balanced circuit is designed to read the signal produced by the difference between the hot and cold wires of the balanced wire. It's called a "balanced differential input".

You can also use an XLR connector with an unbalanced wiring design, such as the 1/8" TRS to 2-XLR cable which I just built to connect my iPod to the XLR stereo inputs in the Yamaha PM5D. Whether a cable is balanced, or unbalanced is determined NOT just by the connector on the end, but how the connector is wired.

Professional mixing consoles (the ones used by professional mixing engineers, and not the entry level six channel cheapo mixers used by most musicians who can't afford to hire a mixing engineer) give you the option of selecting which type of input is coming into the input connector.

If you want a truly quiet XLR cable, get some of the four conductor shielded cable like the Canare L4E6S. You take two pairs of the four cables, twist them together and sodder the two groups of two cable to pins 2 and 3 (or tip and ring) of the connector. It's really a balanced cable that has been balanced again before the connector gets to the input circuit. (And if you want a TRULY quiet guitar cable, use the same Canare L4E6S, twist all FOUR of the conductors together, and sodder them to the tip of the 1/4" TS connector, and the sodder the ground to the sleeve).
 

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Guitar players don't want quiet cables--they want LOUD cables. heehee:D;)

BTW, everything JC has said is accurate, as I understand cables and balanced input, which can be very confusing.

I only encounter TCFH once. I changed the connector on both ends.

The only other weird thing I had with XLR cables was when a TD in a venue had mic inputs scattered around the stage. He had wired a male jack where it would normally be a female jack. Then he wired all of the house's mic cables with female on both ends. All this so no one would steal the house's mic cables.
 

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hakukani said:
The only other weird thing I had with XLR cables was when a TD in a venue had mic inputs scattered around the stage. He had wired a male jack where it would normally be a female jack. Then he wired all of the house's mic cables with female on both ends. All this so no one would steal the house's mic cables.
Oh, that's LAME. If I walked into a house like that, I would turn right around and leave (actually, probably not, but I'd still bitch about it for the whole rest of the gig, and years afterwards :twisted: )
 

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Commercial recording facilities generally use TRS and XLR cables to connect studio monitors to mixing consoles or studio amplifiers. These types of audio cables will be the main focus of this guide.
 
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