How is a guitar usually plugged into a mixer?


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AhrenBa
12-31-2007, 05:12 PM
Hey guys,

I sort of have a thread running with this question buried within, but it was hard to generate an answer since the thread was so long.

Anyways, I am thinking about buying a mixer. How do people usually connect a guitar into a mixer's line input (line level) jack?

I have heard that the signal that is outputted from a guitar is very low volume, and needs to be boosted somewhat.

I realize that there are Hi-z inputs which help boost the signal, but are not true pre-amped signals.

So, how do people connect their guitars or instruments to a mixer?
1. 1/4" cable out from guitar and plug directly into the line input on the mixer? (lowest signal strength)
2. 1/4" cable out from guitar and plug directly into a Hi-z line input? (somewhat boosted signal)
3. 1/4" cable out from guitar, plug into a pre-amp, and then into the line input? (line level)

All of these ways will work, correct? If so, which is most common (best)? Please tell me if I have any of this wrong.

Also, what is the difference between a DI box and a preamp? Can they be used in conjunction with each other? If so, which way is correct:
1. guitar -> DI box -> preamp -> mixer
2. guitar -> preamp -> DI Box -> mixer

Thanks!

EDIT: And on a side question, with soundcards...what is the difference between mic input and line input? Are they interchangeable? Can you plug a device into either or?

Also, if I were to use an external pre-amp with a microphone, and then plugged the mic (now pre-amped) into the mixer's XLR slot, which also contains it's own preamp, how could I bypass the preamp in the mixer? Because...wouldn't that defeat the purpose of using an external preamp if the sound will ultimately also be going through the preamp built in the mixer?

DeathMask
12-31-2007, 05:20 PM
When recording with my digi001 interface, I have my guitar plugged into my amp as usual, and run a cord from the line out of the amp to the input of the interface. I imagine this would be the same for running into a mixer.

AhrenBa
12-31-2007, 05:22 PM
When recording with my digi001 interface, I have my guitar plugged into my amp as usual, and run a cord from the line out of the amp to the input of the interface. I imagine this would be the same for running into a mixer.

Thanks for the reply, DeathMask. That makes sense. Have you tried plugging the cord output from your guitar straight into your interface? Is the signal even usable?

That's one thing I don't quite understand. I realize it is best to amp the signal before inputting it to an interface or mixer, but can you just plug straight into the mixer from the guitar?

skippertipper
12-31-2007, 05:23 PM
When recording with my digi001 interface, I have my guitar plugged into my amp as usual, and run a cord from the line out of the amp to the input of the interface. I imagine this would be the same for running into a mixer.

I think he was talking about an acoustic, but i can't be any help on this. sorry. :(

thrice_removed
12-31-2007, 05:39 PM
It is typically best to mic your amp instead of plugging straight into the board, but since that is not the question I will answer the given question. The proper sequence is this:
guitar -> DI box (converts signal to Lo-z; it is now a stand line level instrument) -> preamp -> mixer.

Take note that some preamps have built in DI boxes (even some mixers for this case). But if it doesn't specifically say that it has a built in DI or specify that a given channel is meant to have guitars plugged directly in don't assume there is one. Hope that helps.

AhrenBa
12-31-2007, 05:42 PM
It is typically best to mic your amp instead of plugging straight into the board, but since that is not the question I will answer the given question. The proper sequence is this:
guitar -> DI box (converts signal to Lo-z; it is now a stand line level instrument) -> preamp -> mixer.

Take note that some preamps have built in DI boxes (even some mixers for this case). But if it doesn't specifically say that it has a built in DI or specify that a given channel is meant to have guitars plugged directly in don't assume there is one. Hope that helps.

Thanks for the reply. What's the use of using a DI box though? Ultimately, if just the signal needs to be boosted, what does the DI box do? Thanks.

If not too much trouble, I added a couple more questions near the end of my first post. If you could take a look, that would be great!

thrice_removed
12-31-2007, 05:49 PM
Ok well first off a HI-z and a lo-z signal are two different kinds of signals. Its not just a matter of one being soft and the other being louder. Hi-z signals pick up a lot noise from radio waves and electrical appliances that Lo-z signals are generally immune to (this is why you never want to have a hi-z signal going over an extremely long cable as it will pick up all manner of noise).

So basically - the preamp works best when dealing with Lo-z signals. They were not made to deal with Hi-z signals - they can, but it is not optimal. Thus, you stick a DI box in front of it that converts the signal to Lo-z (the specifics here are rather complicated) which makes the preamp be able to do its job the way it was supposed to work - amplifying Lo-z signals.

Mic input typically has a crappy built in preamp - line inputs sometimes do not.

If you were to plug an external pre into a channel that already has a built in preamp you would not need to do anything as since the signal is already preamp you do not need to use the preamp on the mixer. Just set the gain on your external preamp to the appropriate level and leave the gain on the mixer preamp at zero and you should be fine. The mixer preamp only adds gain - it won't take away from an already appropriately preamped signal.

AhrenBa
12-31-2007, 06:34 PM
@thrice_removed

Wow! Thanks for the detailed response!

1. Also, do mixers and/or interfaces ever have built-in pre-amped line input slots?

2. When you use a DI box, does it output a XLR cable or 1/4" cable or both? Both XLR cables and 1/4" cables can carry a low-z signal, correct? If so, can lo-z signals be plugged into a line-input?

3. On my guitar amp (it's pretty crappy), there is a "Phones" out which is meant to be used for headphones. Is this "Phones" out the same as a "direct out"? The reason I ask is because I am wondering if the "Phones" out is at line level and is ok to plug directly into a mixer without pre-amping?

4. On a side note, is it ok to plug a direct out from something like a powered amp into a soundcard's line in? I have heard that this could fry the sound card, but I have never seen it confirmed.

5. What exactly creates the hi-z or lo-z signal? I mean... I have heard it is the ratio from the output to the input, but I am somewhat confused on where the "impedance" comes from.

6. Is line-level signal also known as lo-z? If not, what is?

Thanks!

MrPillow
12-31-2007, 07:47 PM
http://www.dysgenicrecords.com/feature.php?id=51

http://www.gainesaudio.com/faq.htm

http://mywebpages.comcast.net/riceaudio/html/Wired.html

AhrenBa
12-31-2007, 09:01 PM
Thanks for the links, MrPillow, I just read through them.

Let's see. I'll see if I can answer my questions:

1. Also, do mixers and/or interfaces ever have built-in pre-amped line input slots?
Not sure, some might, but these are line levels (they expect a line level signal to come in)

2. When you use a DI box, does it output a XLR cable or 1/4" cable or both? Both XLR cables and 1/4" cables can carry a low-z signal, correct? If so, can lo-z signals be plugged into a line-input?
From what I have read, it looks like a DI box outputs XLR? Is this right? I am not sure if both cables can carry lo-z...

6. Is line-level signal also known as lo-z? If not, what is?
No...I think...

Ok, I realize that things like guitars, basses, and mics that output 1/4" produce hi-z signals and that things like mics that output XLR produce lo-z signals. I understand that the impedance comes from the different current on the input and output, but am still confused.

So, the signal ranges goes like this: mic level, instrument level, line level, then speaker level. So this means mic level has the lowest voltage, while speaker level has the highest? Is this right?

So mic level is lo-z and instrument level is hi-z?? I guess I am just trying to figure out the technical difference between the two (like what ohm ratio or whatever makes hi-z or lo-z).

Then there were a couple questions that I still can't answer from post 8. Thanks.

AhrenBa
12-31-2007, 09:44 PM
Ok, I have been trying to work this out in my head.

Let's use a hypothetical situation here: ;)

From http://www.electronics-tutorials.com/basics/impedance.htm
-------------------
Assume you have available these 4 items on your bench:

(a) A series of eight fresh AA type 1.5 volt cells to create a total of 12 volts supply.
(b) A 12 volt heavy duty automotive battery - fully charged.
(c) a small 12v bulb (globe) of very, very low wattage. and;
(d) a very high wattage automotive high-beam headlight.

Now what do you think would happen if we connect the high beam headlight to the series AA cells and conversely the low wattage bulb to the automotive battery?.

The heavy duty battery is capable of delivering relatively large amounts of power but the series string is capable of delivering only relatively minimal power. The first is a low impedance sourceand the other, in comparison is a relatively high impedance source.

On the other hand the high beam headlight is capable of consuming relatively large amounts of power but the minature bulb is capable of consuming only minimal amounts of power.

Low Impedance: High beam headlight to AA batteries
High Impedance: Low wattage bulb to automotive battery
---------------------

However, I am still confused (what a surprise). If these explanations are correct, then why is it that the signals from a guitar and amp need to be pre-amped (boosted)?

According to this (from Difference between line level and hi-z (http://www.recordingreview.com/articles/blogs/86/The-Difference-Between-Line-Level-and-Hi-Z.html) ):
All microphones have an output impedance of some kind. Of course, the microphone is plugged into a preamp which has an input impedance. The lower the output impedance of the microphone and the higher the input impedance of the preamp, the more signal is passed into the preamp.

If you followed the logic from the first example, wouldn't it mean that in a low impedance situation (like a Mic), that the signal wouldn't have to be pre-amped since the difference between the output and input is so great?

And wouldn't it be the opposite for a guitar?

What is meant by "more signal passed into the preamp", is this different than the "volume" of the signal?

Damn, I am confusing myself....wtf....

I guess, does impedance have to do with signal strength (like if it needs to be pre-amped or not)? Because, using this logic, I thought if all of the signal is passed on (low impedance situation), then it wouldn't have to be boosted...

AhrenBa
12-31-2007, 11:36 PM
Actually, you know what might help me most is this:

I am not exactly sure how impedance ratios are measured (in ohm's, volts??), but could someone provide me with usual numbers for each of the following:

Lo-z Output (such as from a mic)
Hi-z/Instrument Output (such as from a guitar)
Line Level (input)
Hi-z Input
Speaker Range

This way I can compare the signal strength of each of these and hopefully it'll make it easier to grasp the concept. For example, what is different about hi-z input that allows it to boost a hi-z output more than a normal line level?

EDIT: I just was wondering, is signal level different than impedance? If so, how?

kody27
05-11-2014, 03:01 PM
A cool trick I learned once for recording clear full sounding guitar tracks:

Plug your guitar straight into the mixer or digital recorder, or mixer into a digital recorder, or interface.

Record the entire track CLEAN. Straight into console. NO effects, reverb, distortion, nothing. Even if the song requires them, pretend you're using them and just play the clean track.

Stop, rewind, now plug an instrument cable from the LINE OUT of the digital recorder/mixer, INTO your pedal board or amp or whatever you would normally play through.

Your recorder is now acting as the guitar, and then you place mics in front of the amp or out of the pedal board into the mixer again, and rerecord the same track with the effects. You can do this multiple times with opposite frequencies raised and lowered on a 10 band EQ for a really full stereo effect. i.e, one track with every other eq frequency raised and lowered, and the second track with the exact opposite frequency settings panned to the opposite speaker. You can also pull this off live with two amps and two eq pedals for a cool full stereo effect.

MOST IMPORTANTLY, when you are mixing down the master guitar track, be sure to INCLUDE THE ORIGINAL CLEAN TRACK under everything else. Just have it sitting there in the mix, mono, or panned hard left and right, whether you have all the other tracks perfected or not. This re-establishes the purest possible signal that came straight from your pickups into the mixer originally, this clean track will be the purest representation of your guitars tone, otherwise going through an amp first would have completely colored the tone. But this way, you can balance out the clean track and the amp's tracks.

Might sound a little complicated, but it's really not and it's quite simple really. Any guitarist should be able to play the clean track without hearing the effects, but I understand sometimes it is necessary to hear the effect such as a delay for certain timing parts, if this is the case simply split your signal into the mixer and into the effects, while first recording only the clean track and just listening to the effected tone with your ears or headphones. Hope this has helped!

GaryBillington
05-11-2014, 04:39 PM
After 6 years, he probably doesn't care anymore.

DisarmGoliath
05-11-2014, 10:02 PM
Sometimes I reeeeeaaallly feel like banning people for bumping threads that are so old. Let this be your warning, if you ever use the site again kody27... bump another thread that has been dead so long, and you'll be joining the previous 26 kodys :o