Various questions concerning sound, amplification and sound reinforcement

[pedro]

Originally Posted by Vanceman

I'm playing without PA support, and the band is always telling me to turn up. Since I'm stand right in front of my cab, I set a stage volume so I can hear everyone else. I'm getting better at turning up.

Just curious what you're using as a bass amp?

[Vanceman]

I'm using a single 15 cab with a Mesa walkabout head. I think you want to be louder than you think it should be, but it's a fine line.

Last Friday, the amp began malfunctioning, and will need to go in for repair. I will be using a Sansamp RBI, Crest CA6, and borrowed Eden 410 for the forseeable future, so now I have to figure out again how loud I'm supposed to be.

[pedro]

I wonder about this power thing. There are a lot of guy that gig regularly and effectively with GK400 and 1x15 cabinet. I assume some of the power issues arise if you are in a loud band but I'm probably wrong but I assume if you're playing with guys that know how to control their volume its probably not as much of an issue in a small venue.

[Liko]

1. Yes and no. Bass frequencies take time to "mature". What you hear standing right next to the amp is not what the guy 5 feet away hears. You can mitigate this by standing 5 feet or so from your amp; then what you hear will be closer to what the audience hears. If you have a PA with a decent mixer, you can change the levels for your monitor seperately from the audience, allowing you to get what you need out of the monitor while the audience hears what they need.

2. The most common mistake I've seen is scooping the bass EQ. In a bedroom situation, and even in a studio situation, that configuration can work. Live, your audience feels the lows, but it's the midrange that makes you heard in the mix. Without adequate mids, you get muddy in a live situation. The next most common mistake is related; boosting the bass because you can't hear yourself, or boosting the volume without cutting bass because you can't hear yourself. Adding bass, or adding volume to a bassy sound, simply makes your sound more boomy, muddy and indistinct. Because bass frequencies are felt more than they are heard, turning them up will not make you more present in the mix, but it will overpower everything else when the room starts vibrating sympathetically. having too bassy a tone can also start volume wars. You're too boomy, you can't hear yourself, but everyone else sure can, and they turn up. That makes you LESS able to hear yourself and you turn up. Pretty soon you're playing through a thousand-watt amp and an 8x10 fridge, your guitarists have 150-watt full stacks, and you're miking the drummer, all for a bar gig. You still sound terrible, but you're now so loud the bar down the street is complaining that their house band can't be heard over your noise.

3. The single biggest mistake sound guys tend to make in live situations is to EQ it like a studio gig: bass gets all the mids and treble cut out of the sound. It works in a studio where the track balancing and modern stereos make up for the lack of presence with raw bass, but again, in a live situation you need mids to be heard.

4. You're not going crazy. This happens all the time. You get used to hearing your instrument a certain way, and think that it needs more treble to cut through. Then the next time you turn it on, your tone has way too much bite. Generally, if you feel your sound has changed, it probably hasn't. Set and forget your EQ. When doing soundchecks before a gig in a new room, remember that bodies absorb sound, so what may seem a bit too boomy might end up just fine with 50 people on the dance floor in front of your speakers. Generally, the first song of the first set should be the sound check, and you should have a soundman making final adjustments based on the room and number of people. You might make your first set a short one (like 15 minutes) and take a quick break to huddle and be reassured by the soundman and other band members that the sound balance and EQ are just fine (or confirm that they're not and make adjustments).

5. The directionality of a sound is directly related to its frequency. Low frequencies are pretty omnidirectional. Trreble frequencies are highly directional. So, standing right in front of the amp is going to sound more trebly versus standing to the side or behind it. There is simply no overcoming this without having PA speakers pointed 360*. In addition, there is an effect produced by multiple speakers called "comb filtering". Not counting room acoustics, no matter how two speakers are positioned, there will always be points in the house where one speaker's sound wave will cancel the other's out. Where these points are depends on the position of the speakers and the frequency of the note. Add room acoustics into this and determining these points becomes a physics and vector calculus exercise. Various methods have been tried over the years to create speaker arrangements that do not have this weakness. It may be impossible to accomplish this in the general case; the best that can be done is to use an array of speakers in front of the audience arranged such that there is always one speaker directly facing each direction, whose output as perceived by an audience member will largely overpower any comb filtering from other speakers. That's an expensive setup, and for most venues it's simpler not to worry about it at all; you'll be loud enough to be heard anywhere in that bar.

[pedro]

What you hear standing right next to the amp is not what the guy 5 feet away hears. You can mitigate this by standing 5 feet or so from your amp; then what you hear will be closer to what the audience hears

Makes sense.

2. The most common mistake I've seen is scooping the bass EQ.

I run my GK700 flat. I set the treble to around 10am and the bass to 1-2pm. The presence is up around 2-3pm.

The next most common mistake is related; boosting the bass because you can't hear yourself, or boosting the volume without cutting bass because you can't hear yourself.

(pedro makes not to self.)

Pretty soon you're playing through a thousand-watt amp and an 8x10 fridge, your guitarists have 150-watt full stacks, and you're miking the drummer, all for a bar gig. You still sound terrible, but you're now so loud the bar down the street is complaining that their house band can't be heard over your noise.

What a nightmare.

3. The single biggest mistake sound guys tend to make in live situations is to EQ it like a studio gig: bass gets all the mids and treble cut out of the sound. It works in a studio where the track balancing and modern stereos make up for the lack of presence with raw bass, but again, in a live situation you need mids to be heard

I’m not sure I’m following. Also, have you found an effective way to communicate this to the sound guys without stepping on anyones toes, so-to-speak?

4. You're not going crazy.

Can I quote you to my wife?

Not counting room acoustics, no matter how two speakers are positioned, there will always be points in the house where one speaker's sound wave will cancel the other's out. Where these points are depends on the position of the speakers and the frequency of the note.

Congratulations that’s the first time I’ve ever even remotely understood that term.

[Vanceman]

Originally Posted by pedro

I wonder about this power thing. There are a lot of guy that gig regularly and effectively with GK400 and 1x15 cabinet. I assume some of the power issues arise if you are in a loud band but I'm probably wrong but I assume if you're playing with guys that know how to control their volume its probably not as much of an issue in a small venue.

True. We usually play small venues where I stand within 3 feet of the drummer sometimes, and I don't consider him very loud. We have 5 vocals and keyboard in the PA, and the monitors are daisy chained to the mains. This way we hear what the crowd hears, and can self regulate the vocal mix, and maybe even the total mix.