Electric guitar connected to Mixer doesnt work

Question

Just wondering if someone could tell me why my setup didnt work.

I have an electric guitar and was supposed to play as part of a choir at one of the churches. I have never played at the church or for that matter in any choir before. The only guitar playing I have done before was at home connecting my electric guitar to my fender mustang I amp.

The info given to me was that the church sound system had a Leem, LMM-6S mixer. I was under the impression all I had to do was connect my guitar to the mixer using 1/4 inch connectors, and it would all would all work, but when I did some reading on the internet I found that I need to have a DI box between my guitar and a mixer. So I went a purchased a Behringer Ultra-G GI100 DI box with all the necessary cables. I tested the DI box at home by connecting my guitar to the DI box and an XLR output of the DI box to the my fender Amplifier using a XLR to TS 1/4 inch adapter. It seemed to work fine.

When I went to the church I connected my guitar to the DI box and the XLR output of the DI box to the XLR input of the mixer, hoping that now I should be able to hear the guitar on the church PA system. There was no sound at all. When I increased the gain on the mixer to a very high level I just got a very feeble sound but that wasn't enough.

I tried connecting the guitar directly to the mixer and that didn't work either. I tried different combinations for quite some time and then gave up. I ended up connecting my guitar directly to the fender AMP and playing in church, but since the vocals were being sent to all the speakers in the church whereas the guitar output was only coming out of my Fender Mustang I amp , the whole performance was nowhere near what I wanted it to be.

Could any of you tell me what I was missing. Why wasnt the mixer sending the guitar output to the church PA system ? Why was the guitar sound so feeble when connected to the mixer?

Cheers, Alex

Answer 1

I am somewhat reluctant to answer the question, due to the fact that I cannot find any further info (such as manuals) for that Leem LMM-6S mixer. I did found a Leem HM-624 which looks at least somewhat similar, but that didn't allow me to download the manual either.

Without further information, wiring diagrams, and details on the actual PA system, the only thing I can offer is a "generic troubleshooting approach" as I would have done it if it were me in the situation.

First of all, the fact that you actually did hear the guitar, but very faint, is a good sign ! It means there is a signal path, although not optimum, there is some signal going from your guitar, through the various components to the speakers.

The approach I usually take in those situations is "follow the signal", and based on your description the signal path is as follows:

1. guitar pickup
2. guitar electronics
3. 1/4" mono/unbalanced cable
4. Active DI
5. XLR/XLR cable
6. Leem LMM-6s desk
7. some-sort-of-cable
8. some-sort-of-PA

The fault of faults can be in any of those components, or combination of.

I ended up connecting my guitar directly to the fender AMP

Now this will rule out 1. 2. and 3. Great !

4. Active DI

There are various things which can go wrong with this. I will mention some of them here. Some you might have checked at the time:

• Does the Active DI have a good 9V battery
• Did you plug the guitar into the INPUT jack ? (and not the thru-jack) -- this should turn on the unit
• Were the PAD switches engaged ? (-40dB attenuation)

5. XLR/XLR balanced cable

Did you use your own cable ? (which you tested at home) or was the cable already installed in the venue ? did you try another cable ? was the cable known-good ? (e.g. did you check the cable with a microphone or other sound source ?)

6. Leem LMM-6S desk

The following depends on where the signal comes into. If it was channel 1 or 2, this is a Mic input (the DI in question has MIC level output, so that would be correct), and you need to ensure the following:

• Was the GAIN of the channel turned down ?
• Was the PAN set to full Left or full Right ? -- if the PA is a mono system you can make the mistake of "panning" your signal to the wrong output
• Was the main fader (rotating in this case) turned down ?
• Was the channel tested with another signal source ? was it working/known-good ?

For channels 3/4 and 5/6, these are stereo channels. Usually (but I am not sure as I do not have a manual of this mixer) the Left-input is the mono input.

• Was the correct input used ?
• Was the PAN set to full Left or full Right ? -- if the PA is a mono system you can make the mistake of "panning" your signal to the wrong output
• Was the main fader (rotating in this case) turned down ?
• Was the channel tested with another signal source ? was it working/known-good ?

7. some-sort-of-cable

8. some-sort-of-PA

since the vocals were being sent to all the speakers

It seems that the mixer out and to the PA were working.

This should give you a good approach for the next time, if you have more info, update your post, and I will update this answer.

[EDIT - let me share a tip]

One of the things I (sometimes) do, is take a picture of the channels/desk with my mobile phone, in case things are right (so I can come back to the same settings) but also when things are wrong (so I can look afterwards to see if I have made a mistake and learn)... maybe next time you can too !

Answer 2

As you'll know, an electric guitar typically requires amplification to be heard, hence usually plugging it into an amp! On top of this you usually throw a bunch of standard distortion and reverb effects, and EQ, that your amp will offer. The DI box performs this amplification when you are using a PA system, or recording straight into a computer, etc etc. Just plugging your guitar straight into the mixer, without an amp, would result in the very quiet, raw, electric guitar sound being fed into the mixer.

In your case, the plugging your guitar into your DI box, then into the mixer, should have worked. There are two things I can think of that may have caused it not to.

• Silly question, but did you have it powered? The Behringer Ultra-G GI100 requires either +48V phantom power (from the mixer) or an internal battery in order to work.

• If it was powered, then perhaps you has the switchable input attenuation on the wrong setting?