How do you measure SPL?

[SOMMS]

Hola amigos,

 

I had a few (more) basic questions for you.

 

1-How do you acurately measure SPL (sound pressure level)? Is there is a device you use? What is a good (perhaps sligtly loud) SPL level for a guitar rig for a metal act?

 

2-What do 'continuous', 'program' and 'peak' wattage figures mean when you are looking at the specs for a speaker cab?

 

 

 

 

Thanks.

 

 

-SOMMS

[ctardi]

I beleive you would use a SPL meter.

[Steve_B]

Sound pressure is the dynamic variation of the static pressure of air. That is the total instantaneous atmospheric pressure at a point, minus the static (average) pressure at that point. It is measured in force per unit area and represented by the symbol p.

 

Sound pressure is normally expressed on a logarithmic amplitude scale, which gives a better relationship to the human perception of hearing. It is an open-ended scale and a sound level of 0 dB is considered to be the average threshold of human hearing. 60 to 70 dB is about normal conversation, 110 dB to 120dB would be a loud gig, and 150 dB for the noise of a rocket takeoff or a jet engine at close range.

 

You can measure the sound pressure level with various weighting filters whose characteristics approximate the sensitivity of the ear at various frequencies and levels based on the Fletcher-Munson curves. Commonly used is the

[where02190]

With a $30 Radio Shack SPL meter of course.

[MrKnobs]

Originally posted by where02190 With a $30 Radio Shack SPL meter of course.

 

I have two $8000 B&K SPL meters I use at my job.

 

I've been thinking about taking one to a show to compare to my RS meter, but if I lost it and had to repay my workplace that might smart a bit.

 

Terry D.

[where02190]

A couple years back I produced a project that was mastered by the master of mastering engineers, Bob Ludwig. I of course attended the mastering session, and during this, I notice one of the se $30 RS meters in the midst of all of Bobs high end and custom designed electronics. He noticed that it caught my eye, and he chuckles, turns to me and says, " You got one in your studio too, don't you? Of all this megamoney gear I have at my disposal, this (holding up the $30 RS meter) is the one I rely on most."

 

We both had a good chuckle on that, and continued on our mission, relying of course on the $30 RS meter to keep us in a consistant SPL.

[SOMMS]

Alrighty...$30 at Radio Shack. Any brand to look for or is there only one? (RS?)

 

 

 

Also, as a sound engineer...what is the loudest guitar amp level (in terms of db) that you can still work well with??

 

 

I know it makes a total difference what venue and what system you are working with, so lets just assume the average 200-300 person indoor venue with an average system (whatever that would be). I'm looking for a ball park volume level for guitarists. For example, I go in and my amp is putting out 120db FOH...is this too loud? Probably. I turn down so my amp is putting out 80db FOH...is this too quite...probably.

 

What is a workable guitar amp volume level for a loud hard rock act?

 

 

 

SOMMS

[ctardi]

80 too quiet, 120 too loud. Somewhere around 95 is 'good enough for rock and roll.'

 

Isn't that a song?

[bigmike216]

80 would be lovely

[ctardi]

Originally posted by bigmike216 80 would be lovely

 

Are you one of those people who wins prizes at spl comps for yelling louder then their car?

[Brad Harris]

Originally posted by ctardi Are you one of those people who wins prizes at spl comps for yelling louder then their car?

 

Well if there wasn't a rig in there or supplied, then 95 isn't bad, but then how would you hear the vocals? :D

 

Better quieter than too loud, but there is a too quiet. I find 85-95 is fine for me, unless there is a SPL limit (like my last show of 90dB for a hard rock show )

 

The show went a little easier when the SPL 'cop' let me put him in the same weighting scale as the rest of the world.

[where02190]

120db of anything musical is too loud.

 

80 is divine. It really depends on where you are measuring. 80db at the back of the room is pretty decent with the PA off. 120db at the cone is decent as well in a good sized room.

 

It should be loud enough for you to hear it, but no louder. Also, aiming speakers at your ears and not your ass is very helpful.

[Steve_B]

I must admit that it is slightly unusual for a guitarist in a loud hard rock act to be worried about levels. Usually there are only two levels, too loud and way too loud.

 

If all you need a sound level meter for is to set your guitar level I wouldn