[Kel Ghu]

Hey ppl,

I don't get the meaning of "balanced" stuff... Balanced cans, balanced amp, to balance this and there... How do you balance an amp or cans? And what does it do to sound?

Thank you!

 

[ClieOS]

To balance a can, you need to recable it (or at least, change the jack).

Balanced amp are designed to produce balanced signal. Not balanced amp can not be modified to be balanced (or at least, very difficult).

Before you ask about how to 'balance' stuff, best get the concept of how it works. See Headroom's guide.

You might also be interested in Meier's balanced ground concept, which doesn't require a balanced 'phone to work.

 

[ericj]

It's a term that we misuse here.

In pro audio, 'balanced' audio is audio that is signalled differentially rather than single-ended. That is to say that there is the regular audio signal, and an inverted audio signal comprising the total signal sent and received by balanced components. This increases the signal to noise ratio by 6db, which is good. It makes it extremely easy to reject common-mode interference in the receiving component - something headphones cannot do. It also helps decouple the 'ground' voltages of components, which prevents ground loops.

What car audio and other amplifier types call "bridged" is what we in headphones call "balanced". We probably call it "balanced" because typically we use the same 3-pin XLR connectors as pro audio gear use for balanced audio.

 

[alphaproject]

I would imagine that other than the technical stuff, if the cans equally disperse bass, midrage, and treble without giving off of too much of either 3, then they are balanced. Some people like balanced but others are bass heads, etc.

Personally I'd like the cans to be able to produce alot of bass if it can, rather than not being able to at all. Or...pout it this way... I'd rather take away some low end then have to artificially add more via EQ.

Like if I get the DT770's..... I may or may not eq the low end off a tad if it's too much.....rather than the Sennheisers 280 pros, adding more low end to hear it.

 

[ericj]

Quote:

Originally Posted by alphaproject /img/forum/go_quote.gif I would imagine that other than the technical stuff, if the cans equally disperse bass, midrage, and treble without giving off of too much of either 3, then they are balanced. Some people like balanced but others are bass heads, etc.

Nope. Has nothing at all to do with it.

In the traditional single-ended topology, the coil in your headphone has one lead connected to the signal and one lead connected to ground. If we imagine that ground is 0 volts (which i assure you is imaginary), the voltage coming across the signal wire goes above and below the ground point, which pushes the diaphragm forward and backward.

In the differential or 'balanced' topology, neither lead is grounded. Instead, while the voltage on one lead is going positive, the voltage on the other lead is going negative at exactly the same ratio.

This effectively doubles the gain and allegedly quadruples the effective power, which is all pretty reasonable to expect because you built a little more than twice as much amplifier circuitry to do it. And come on, those XLR connectors are huge - and that's got to count for something, right?

The differential signalling topology *may result in better control of the diaphragm, which *may result in tighter, more controlled, less warbly bass.

But it won't change the frequency response of the headphone system as a whole.

 

[nikongod]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif It's a term that we misuse here. What car audio and other amplifier types call "bridged" is what we in headphones call "balanced". We probably call it "balanced" because typically we use the same 3-pin XLR connectors as pro audio gear use for balanced audio.

i strongly disagree with that.

while it is somewhat conditional on the amp, the vast majority of the balanced amps used here are balanced from the inputs to the outputs. i actually cant think of many that are only "bridged" aside from t-amps.

i suppose you could question whether the ADDITION of a single ended input and a phase splitter effects the amp. the obvious answer is that in single ended mode it does, and if its removed from the circuit in balanced mode it does not.

please dont insult an amp because the source isnt capable of keeping up. any source worse than the amp in the digital age is a joke.

 

[Nebby]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif It's a term that we misuse here. In pro audio, 'balanced' audio is audio that is signalled differentially rather than single-ended. That is to say that there is the regular audio signal, and an inverted audio signal comprising the total signal sent and received by balanced components. This increases the signal to noise ratio by 6db, which is good. It makes it extremely easy to reject common-mode interference in the receiving component - something headphones cannot do. It also helps decouple the 'ground' voltages of components, which prevents ground loops. What car audio and other amplifier types call "bridged" is what we in headphones call "balanced". We probably call it "balanced" because typically we use the same 3-pin XLR connectors as pro audio gear use for balanced audio.

Just a few questions to see where you're coming from:

Why can headphones not gain the benefit of common-mode noise rejection? Both + and - lines receive any possible noise, and the headphone speaker effectively does not see the noise since they cancel each other out. Also, what are you basing your statement on, that in the headphone world, bridged = balanced?

 

[ericj]

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif i strongly disagree with that. while it is somewhat conditional on the amp, the vast majority of the balanced amps used here are balanced from the inputs to the outputs. i actually cant think of many that are only "bridged" aside from t-amps.

A four channel amp is still just a four channel amp whether or not it includes a phase inverter on the front end.

And whether the phase inverter is in the amp or the source, matters less than you think.

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif please dont insult an amp because the source isnt capable of keeping up. any source worse than the amp in the digital age is a joke.

Maybe i'm questioning the supposition that it's a good idea to spend more than twice as much on the amp to make up for a shortcoming in the driver design.

Quote:

Originally Posted by Nebby /img/forum/go_quote.gif Just a few questions to see where you're coming from: Why can headphones not gain the benefit of common-mode noise rejection? Both + and - lines receive any possible noise, and the headphone speaker effectively does not see the noise since they cancel each other out. Also, what are you basing your statement on, that in the headphone world, bridged = balanced?

Maybe i should have said that at the power levels used in headphones, the common-mode rejection is a faint shadow of a moot point.

As for the other, "balanced" signalling is a method of protecting the integrity of an analog signal in transport.

What we're doing with headphones that have a pair of XLR connectors is a method for improving power delivery.

The only problems with moving-coil drivers that you could potentially ameliorate with differential signalling are contamination of ground currents - which you can also fix with an active current sink on the output ground (aka "ground channel"), and the reactive nature of, well, coils, when they receive a large transient, like a bass note. The impedance of the coil increases as it's field nears saturation, and the inverted signal on the other side *may help the amp deal with the situation.

These are both problems that, for the most part, can be solved with improved amplifier design while maintaining the single-ended topology.

Or by improved driver technology. But if y'all want to keep using moving coils, you have that right.

fwiw, yes, electrostatics are almost always driven by differential amplifiers - because the drivers are designed to be pushed and pulled from both stators. A back-electret could be driven single-ended just about as well as it could be by a differential amp, but not a traditional electrostatic or electret.

 

[phkd]

good post. thanks!

 

[nikongod]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif A four channel amp is still just a four channel amp whether or not it includes a phase inverter on the front end. And whether the phase inverter is in the amp or the source, matters less than you think.

How should a fully balanced AMP be made then? it is really weak criticism to say that something is not what everyone says it is when what you think it should be dose not exist. could you perhaps provide an example?

please also note: an AMP is a device in the SYSTEM. the fact that the source (may or may not) be "properly" balanced is irrespective of the function of the amp.

that naturally brings us to this: please tell us how a fully balanced source should be made.

 

[Carmantom]

I feel a good one coming on.

 

[ericj]

*shrug* not really.

I'm not going to try and lecture anyone on how to build a balanced amplfiier - because i don't care.

What I've been saying is that it's an unnecessary, overkill solution to a problem that you don't have to have in the first place.

 

[nikongod]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif What I've been saying is that it's an unnecessary, overkill solution to a problem that you don't have to have in the first place.

as well as saying that the majority of what people here call balanced is actually a bridged load toppology.

 

[soundfreq]

can either ericj or nikongod explain more the difference between the topologies such as bridged and balanced? it would certainly help the op and others as well. thanks

 

[ericj]

Quote:

Originally Posted by soundfreq /img/forum/go_quote.gif can either ericj or nikongod explain more the difference between the topologies such as bridged and balanced? it would certainly help the op and others as well. thanks

I thought i did.