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NEW! Reso-Acoustic Sound System

LIVE SOUND REINFORCEMENT (for National Guitars)

This will be a brief discussion of methods for optimizing your sound through a P.A. system, with microphone and with microphone/pickup combination. This information has been gathered over a lifetime of experiences doing performances around the globe in venues from 100 to 12,000 seat capacity, and doing sound checks in ten languages with varying levels of equipment quality and soundperson attitudes. I've kept these techniques quite secret for years, but now that there are so many of you dedicated players out there spreading the resophonic word, I've decided to share this information to make your working lives easier!

There are many issues here, so I will take them one at a time.


MICROPHONE SELECTION:

Condenser mics work better than dynamic mics, though I spent years using whatever Shure SM57 was provided by the venue. The EQ techniques described below work great with a 57, and therefore will work even better with a condenser! If you can afford the best, I recommend a small-diaphragm Neumann studio mic with a cardioid or hypercardioid (better) pattern (narrower field of sensitivity). I've used the Neumann KM 84, KM 184, & KM 150 with great pleasure. Large-diaphragm mics are too sensitive for stage use. These models have small diaphragms.

If the high price of a Neumann scares you, don't worry. There are many fine condenser mics out there starting at maybe $150 and up. Check out Shure's SM81, or try the various AKG condensers, which probably range from $250 to $800.

However, I found my KM-150 five years ago for $1,100. That works out to about a dollar a gig since then-well worth it for the great sound! Remember 2 things: A microphone is an INSTRUMENT, and it is your main link from your artistic expression to what the audience hears.


BASIC MIC POSITIONING RELATIVE TO THE INSTRUMENT:

Normal microphone working distance is 4 to 6 inches away, but often I get as close as 1 inch, to produce the effects described below.

National resonator guitars have an acoustic feature that is absolutely unique: You can radically change the timbre (Treble-Bass Ratio) of the P.A. sound simply by moving the body of the guitar around relative to the mic!! With a condenser mic (and even with an SM57) the effect is so dramatic, that if you do it correctly, listeners will think they are hearing two instruments!

Here's the deal: The openings in the upper bouts (f-holes on a single-cone, grilles on the tricone) provide lots of bass (70Hz to 150Hz), and the resonator area provides lots of upper mid- range and treble (1K Hz and up). In the course of a single song, I move in and out and left and right. The left and right movement changes the timbre, and the in and out changes the bass-treble ratio even more, due to the proximity effect (more bass as you get closer to the mic) of most mics. You must experiment with this to learn to do it smoothly and musically.


EQ: USING EQUALIZATION TO MAXIMIZE SOUND AND ELIMINATE FEEDBACK

NOTE: This is not meant to be a course in sound reinforcement. If there is something you don't understand, check out magazines and websites concerning "How to do a Soundcheck."

I always do monitors last, to ensure the best possible sound without feedback in the house speakers, which of course is what your audience hears (after all, why ARE you at the gig?). Also, if you have a good strong house sound, you won't need a lot of monitor level and then you won't have all the feedback problems that hot monitor levels create.

There are two places to work on EQ. First is your mic channel on the console. The best desks will have at least 4 bands of EQ on each input channel: "bass, lo-mid, hi-mid, treble." Even better is when you can select (sweep) frequencies to boost and cut.

The worst desks only have treble (10K) and bass (lOOHz). Next step up are desks that have bass, mid, and treble (fixed frequencies). Next step up are desks with bass, lo-mid, hi-mid, and treble (fixed), OR bass, mid, treble, where the mid-frequencies can be "swept" (to select a frequency to cut or boost).

Next step up are desks with bass, sweepable lo-mid, sweepable hi-mid, and treble. The very best desks have sweeps on all four (rarely found in clubs).

Remember: non-sweep gives only boost or cut at fixed frequencies, whereas sweep means you can select a particular frequency to cut or boost.

Extra hint: The common frequency for the fixed BASS (channel) knob is usually 80Hz, but can sometimes be 100Hz (not as good). The 80Hz corresponds roughly with your low E string.

If you have only one mid knob that sweeps, then start by boosting 1.8K Hz by 2 or 3 db. This is the magic frequency for Nationals! This gives you cutting power and great sounding treble. Most sound people will boost a much higher frequency if you ask for brightness, but 1.8K is really what you want. The Ideal Channel EQ if you have all four sweeps is as follows:

 RANGE  CUT OR BOOST  @ FREQUENCY
 BASS (low E or D): +1 or 2 db  @ 70-80Hz
 LOW-MID (Low A string to open B string):  -1 or 2 db @ 125Hz OR -1 or 2 db @ 250 depending on the room*
 HI-MID: +2 or 3 db @ 1.8K
TREBLE: +1 db @ 10K-12K

(* Often I cut 250Hz on the channel and 125Hz in the house graphic, or the other way around, also depending on the system and room. Some halls have small problems at 125Hz.)

Next, you must (gently and politely) ask the soundman to open up the microphones and use his house graphic equalizer to EQ the room. This means to keep raising the levels until feedback ringing starts and then selectively lower the level at the particular frequency that's ringing. Have him keep turning up, eliminating various frequencies that feed back. If you are using mics in a hall, the hall cannot be EQ'd using a CD - The mics must be on because that is what is being used on the gig. Many rooms need a cut at 125Hz, but don't worry about losing bass, because you have boosted the frequencies below that.

Here's a rough guide to frequencies on your guitar, to help you teach yourself how to know what frequency is feeding back. The sound people will be impressed if you hear a ring and say, "could you please turn down 630Hz?"

These frequencies are approximate, but are close enough, and correspond with available graphic EQ frequencies, and therefore work well with sound engineers and EQ systems.

Use this framework to estimate frequencies that are ringing.

Low E

80Hz

(G on low E = 100Hz)

Low A

110Hz

(C on low A = 125Hz)

E on D string 2nd fret

160Hz

.

A on G string 2nd fret

220Hz

(G on open 3rd stg = 200Hz)

C on B string 1st fret

250Hz

.

E on 1st string

320Hz

(A on 17th fret 1st stg = 880Hz)

A on 1st string 5th fret

440Hz

(B on 7th fret harmonic= 1KHz)

E on 1st string 12th fret

640Hz

(E on 5th fret harmonic = 1.25KHz)




TYPICAL BANDS ON A GRAPHIC EQ ARE:

20Hz, 40Hz 50Hz, 63Hz, 80Hz, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1K, 1.2K, 1.6K, 2K, 2.5K, 3.15K, 4K, 6K, 8K, 10K, 12K. Each one controls more than just the exact numbered frequency, but boosts or cuts a "bell" around each frequency. For example lowering 200 will also slightly lower 180-220.

Now, everything I have said up to here only concerns microphones. My strongly-held opinion about pickups is that no pickup sounds good by itself! It must be used in a blend with a mic. In fact, I get great sound in huge venues using only the mic and equalization techniques described above. However, if you play in a band, or want hotter monitor levels, a pickup can be useful. Please understand that, in a sense, Nationals are feedback machines; so do not expect to plug directly into a guitar amp at high volume without a lot of EQ. (For this application you should definitely have at least an EQ guitar pedal).

I run my Highlander piezo pickup as follows: Out of the guitar to the Highlander battery box, then to a Boss EQ pedal, into the D.I. box, then to the desk, where I ask for:
+1 db @ 70-80Hz
- 1 db @ 125Hz
- 4 db @ 3.5K (to get rid of the nasty piezo pickup sound)
+1 db @ 10K

There is also the new tricone Magnaphonic pickup, NOT a piezo, and this one is so accurate that it requires very little EQ:
+1 db @ 70-80Hz
-1 db @ 300Hz
+ 2 db @ 1.8KHz
+ 1 db @ 10KHz

Then, after I've gotten my great mic sound, I SLOWLY add in the pickup level to the mix. I run about 80% mic and only 20% pickup, which results in a real acoustic sound quality, but with a little more punch, and a little more bass. I will often put a simple 2-second no-pre-delay reverb on the pickup and the mic. No reverb in the monitors.

Everything I have said here concerns the main speakers. For the monitors, add them in slowly, making sure you can still hear the mains - Use the mains as part of hearing yourself, don't just rely on the monitors. Remember, the lower you can run the monitors the less feedback you'll have on stage. You can also fine tune the monitor sound if there is a graphic EQ dedicated to the monitors. (see monitor hints below)

What I have said here about mic/pickup blend applies to solo gigs. If you have a band, the pickup signals are very useful for sending to your drummer's monitors, and also you can use a greater amount of pickup signal in your monitor mix. You should still try to send yourself as much of the external mic as possible. And finally, remember: too much monitors causes loss of perception of the house sound.

As of 2002, Highlander makes a wonderful new 2-channel pre-amp box which includes 4 sweeps (tunable EQ cut-or-boost) per channel, so all of the above pickup EQ settings for pickups can be dialed in on stage and sent out to the desk.


SOME HANDY TRICKS FOR MONITOR EQ:

If there is a separate graphic EQ for the monitors, cut bass frequencies somewhat(80-125Hz, especially 100Hz) - you don't need them to hear yourself, and acoustic guitars can have bass feedback on monitors because of the physics of bass waves and mic-monitor distance. Cut some @200-250Hz and add a little 1K, this gives clarity at lower volumes.

Don't forget: be nice to your sound engineer - your gig depends on it. Be sure to use their name, and tell 'em they did a great job, even if it was you who did the fine tuning with your new knowledge obtained here. Thanks and best of luck.


BOB BROZMAN

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