[BlakIce]

I plugged 2 different Mics into the line in, and then i went into the sound settings and and switched it to line in and i didnt hear anything in garage band, is it broken or am i doing something wrong

[tooki]

It's a Line In, not microphone input. You need a microphone preamplifier.

tooki

[megasad]

Does anyone know why Apple do this on their machines?

[Earth Mk. II]

[list=1][*]Try increasing the input level in your Sound prefs.[*]If you're using a 1/4" to 1/8" converter, the input is probably in mono. Make sure GarageBand is set to a mono input and has channel 1 selected.[*]Some mics may need a preamp. Depends on the model and type of mic. (a cheep desktop mic won't need one, but a better recording mic probably will)[/list=1]

Originally posted by megasad:
Does anyone know why Apple do this on their machines?

Why does Apple do what on their machines? Be less vague.

[megasad]

Originally posted by Earth Mk. II:
Why does Apple do what on their machines? Be less vague.

What the guy before me said they do:

Originally posted by tooki:
It's a Line In, not microphone input. You need a microphone preamplifier.

I've noticed that it's Line In only, not a microphone port, on an old iMac DV+ and on a 1GHz Titanium PowerBook, and I assume it's how Apple handle audio input on all current Macs save the iBook. I know that all current Macs have a built-in microphone, but too often the sounds of the machine (fan, hard drive etc.) can be heard when listening to the recording. What are the technical reasons for not allowing regular (unpowered) microphones to be used with a Mac, without the need for any other equipment? This has bothered me for a while, but I've not bothered to ask about it. Is there a technical reason, such as power interrupting with the signal? Or is it because Apple want to encourage the use of higher quality audio input devices?

[spiky_dog]

cheap mics provide output at line level. good mics provide output at mic level. a mic level port would be unusable for line level devices, therefore apple chose the more useful (in the general case of plugging in stereos and such) line in.

[Spheric Harlot]

Originally posted by spiky_dog:
cheap mics provide output at line level. good mics provide output at mic level. a mic level port would be unusable for line level devices, therefore apple chose the more useful (in the general case of plugging in stereos and such) line in.

In addition, mic pre-amps are extra parts and costs, especially since microphone pre-amps need *real* components and can't be done with a simple chip set.

A small-enough pre-amp housed within the computer case would probably also be subject to pretty strong interference from the electronics, since the amplification is so high.

-s*

[megasad]

Well, hot dog! Thanks for those reasons, the both of you. I guess that's why the soundcard on my old PC had both a microphone port and a line-in port? Makes a whole bunch of sense now. So I guess Apple could get around it by having two audio input ports, both microphone and line-in? Yeah, not too likely. So, how much would a cheap-ass powered-mic cost anyway?

[Spheric Harlot]

Originally posted by megasad:
Well, hot dog! Thanks for those reasons, the both of you. I guess that's why the soundcard on my old PC had both a microphone port and a line-in port? Makes a whole bunch of sense now. So I guess Apple could get around it by having two audio input ports, both microphone and line-in? Yeah, not too likely.

Hmm.

Size is a definite consideration with analog circuitry, especially if it needs to be shielded. On the laptops, at least, most ports are either/or decisions, since there just isn't enough room on the motherboard. (For example, on the tiBooks, when Apple added an audio line-in, they had to do so at the expense of the IrDA port.)

That probably goes for the iMacs, as well.

On the PowerMacs, I'd venture that almost anybody who's going to be doing stuff that requires a mic pre-amp will not be satisfied with a $4 included circuit.

IIRC, the newer (fall 2003) Powerbooks/iBooks have 24-bit inputs, though - can't they take just about any non-powered mic?

-s*

[megasad]

Originally posted by Spheric Harlot:
IIRC, the newer (fall 2003) Powerbooks/iBooks have 24-bit inputs, though - can't they take just about any non-powered mic?

Could someone with such a machine please try this out for me? It would be a mighty fine thing if this were the case.

[tooki]

OK, let me try to explain this in an unambiguous way:

There are several types of inputs. I'll illustrate the two relevant ones:

- line-level: generally 4V p-p (peak-to-peak). This means that you have a signal that swings up to 2V in each direction (positive and negative)
- mike-level: a microphone creates very small currents (in the millivolts). A mike input takes this really tiny input and converts it to line level.


Now, a microphone preamplifier (the electrical doohickey that takes mike level input and amplifies it to line level) can be built into the computer (Apple stopped doing this in 1992), it can be a separate box, or it can be in the microphone itself (Apple's PlainTalk mike did this, as do some midrange mikes). NO cheap microphones do this! NO "PC microphones" do this!

To make this extra-clear: cheap mikes do NOT provide line-level output! They are generally either electret (capacitive, a.k.a. condenser) or dynamic (magnetic) mikes, which require no power source, and just output very small voltages (the mike-level output). Other mike types do need power sources, but for standardization's sake, they output it at mike level! (Note that professional dynamic and condenser mikes exist, too.) Also in pro audio, something called "phantom power" exists, which is a source of power for mikes, so they can output mike level.

The audio on the 15" Aluminum PowerBook G4 is 24-bit, 44.1KHz. The audio on the 12" and 17" models is the traditional 16-bit, 44.1KHz style. (Source: Apple's developer technotes). NONE of them accept mike-level input: they are line-level inputs. The number of bits has ABSOLUTELY NOTHING to do with whether it's a mike or line level input!!!

The upshot of all this?

1. Basically, do not expect ANY microphone to work on the line-in.
2. Buy a mixer (which will have mike inputs and line-level outputs) or a mike preamp, then you can connect the output to the line-in.
3. Or buy a USB or FireWire audio interface that has mike inputs.

tooki

[megasad]

Originally posted by tooki:
...Basically, do not expect ANY microphone to work on the line-in.

Thanks for clearing that up.