Acoustic Guitar / Vocals Amplification

Posted: Wed Nov 12, 2008 10:40 am

Hi All,

I have read as many internet "How to set up PA system's guides" as any one man should but they all seem to miss the same point. How to get the sound out of the guitar in the first place.

My housemate plays electro acoustic and sings. He has started moving to bigger venues (say 50 - 200 people, coffee shops, bars, pubs and clubs) where amplification is needed. For a few songs he is joined by other guitarists / vocalists. I am going to try and work the sound for him / them. So i have two questions: 1) should we plug the guitars in and use the electro-acoustic pick-ups or mic up the guitars using sm57s? And 2) should that resulting signal go straight to guitar amps or to a mixer > Power Amp > Speakers or di boxes > mixer > amp > speakers.

If the answer is to go straight to guitar amp how do you control levels or add compression and eq or in such a small venue is it not needed?

Any help would be much appecieated!!

Posted: Wed Nov 12, 2008 5:17 pm

Im assuming you have a mixer, amp, and speakers. Use the pickups in the acoustic guitars rather than miking. You can use a DI if you choose, not a huge deal if you arent running a real long cable. Run it into the mixer, same with the vocal mic. Run the mixer into the power amp, then into the speakers. Basic, simple and effective. EQ as needed.

Posted: Wed Nov 12, 2008 7:45 pm

just to generate other ideas, when i performed acoustically i would plug the guitar (passive fishman pickup, so a little quiet) into a tube mic pre (and also a tube EQ) that had two outputs. the XLR out would go to the board, and the 1/4 to an Fender Acoustasonic that would be miced and which also had a line out that went to the board. it gave a lot of options and sounded pretty full, depending on who was mixing (or how i played...). not sure if it was overkill...

Posted: Wed Nov 12, 2008 7:47 pm

BDM wrote:

just to generate other ideas, when i performed acoustically i would plug the guitar (passive fishman pickup, so a little quiet) into a tube mic pre (and also a tube EQ) that had two outputs. the XLR out would go to the board, and the 1/4 to an Fender Acoustasonic that would be miced and which also had a line out that went to the board. it gave a lot of options and sounded pretty full, depending on who was mixing (or how i played...). not sure if it was overkill...

sounds like overkill to me. i play acoustic covers for a living and i dont do near that. i do just as i described above with the help of onboard effects on my board

Posted: Wed Nov 12, 2008 9:21 pm

Playing live in that size of venue can give you feedback problems if you go about things the wrong way. For that type of music, there is no need to mic the guitar amp.

The performer should use the amp as his own foldback. Choose an amp that has a DI output taken from before the final gain control, but after the effects. That means that the performer has control of the sound he generates, but any changes in his foldback level do not affect the DI feed.

Your job as PA man is then to take his DI feed and his vocal mic and balance them, with house EQ if necessary, for the FOH speakers. Other performers' feeds can be added into your mix. Don't try to be too fancy, and don't take the control of production of tone away from the performers.

Posted: Thu Nov 13, 2008 6:26 am

thanks guys, theres some really interesting ideas there. I didnt know you could pre amp a guitar in the same way as vocals.

Quote:

Playing live in that size of venue can give you feedback problems if you go about things the wrong way. For that type of music, there is no need to mic the guitar amp.

The performer should use the amp as his own foldback. Choose an amp that has a DI output taken from before the final gain control, but after the effects. That means that the performer has control of the sound he generates, but any changes in his foldback level do not affect the DI feed.

Your job as PA man is then to take his DI feed and his vocal mic and balance them, with house EQ if necessary, for the FOH speakers. Other performers' feeds can be added into your mix. Don't try to be too fancy, and don't take the control of production of tone away from the performers.

I really like the sound of this. Definately going to give that a try. unfortunately the only amp with a direct out is broken, another thing to add to the shopping list!

The problem is the pickup in the guitar (unnamed) picks up the small strings / high frequencies much more than than the lower notes. A combination of how the performer plays, a poor pickup and i think the pickup lies in the bottom of the guitar so its closer to the smaller strings.

I suppose it will have to be a journey of discovery and experimentation.

I might try a combination of pickup and mic'ing the guitar or mic'ing amps while we wait (save up for ?) an amp with a di out. What guitar amps / power amps / speakers do you guys use?

Thanks again.

Posted: Thu Nov 13, 2008 8:30 am

I really try to avoid miking acoustic guitars, Ive just had not so great results 50% of the time.

My PA consists of a Yahama MG166cx Mixer, Yamaha BR15 Mains (2), and a Crown XLS 202d power amp. I also use monitors with an amp as well.

Posted: Thu Nov 20, 2008 2:15 am

There are many different options for a solo or duet performers in small spaces. I have a Taylor 314ce which has a great sound from the acoustic electric output. I run that into a Hartke Acoustic Ribbon amp http://www.samedaymusic.com/product--HTKAC75 which gives me control over stage volume (foldback.) This amp has a direct out xlr that can be used pre or post of the preamp circuit/effects which I use post so that "my sound" goes to the mixer. The vocal mic goes direct to FOH and I use a Hotspot monitor in most small venues, with only vocals in the monitor. If I am joined by another guitarist they are usually playing electric lead and they just use their amp either mic'd or direct out. In very small venues, for example a coffee house, a great deal of the "acoustic" amps have a seperate channel for a vocal mic and this is sufficient for quiet crowds, very handy as it greatly reduces the amount of gear needed. If we are all playing acoustic then we can mic things but if the players are not used to being mic'd there are a raft of problems, feedback, keeping a consistent distance from the mic, as well as brushing into the mic or stand so I try and stay away from it whenever possible.
As far as the unbalanced sound generated by the guitars high strings, the guitar should be adjusted by a good guitar tech or luthier to make certain it is set up correctly. The other issue is most acoustic electrics have some type of EQ built in and players who have a good grasp of their instrument acoustically often lack the ability to adjust the electric sound properly. If his guitar has such a unit built in start with a 50-75% volume (gain settings will alter the tonality) and relatively flat EQ and work from there cutting slightly the highs and gently boost the mids and or bass. If the guitar is totally passive, no controls, then the use of a stompbox EQ for about $75.00 might help this. The other possible problem is the PA system might require EQ because of the way the speakers or the room are reproducing sound.
Just remember if the guitar does not have good sound to begin with....garbage in = garbage out.

Jim

Posted: Sat Nov 22, 2008 11:25 am

Quote:

Just remember if the guitar does not have good sound to begin with....garbage in = garbage out.

Dont tempt me - i keep using this as my excuse for awful recordings!!

Thanks for you advice JG, some great ideas there.

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