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dB behind and in front of the speaker

DNathan

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#1
I measured a PA last night at 95dB in front of the speaker and 93dB behind it - and was surprised it was so similar. I was trying to determine if I could tolerate being on stage with a PA system playing hard rock. (I have severe tinnitus & hyperacusis and want to determine if I should even dream about this.)

But if I put a rock band together as lead singer I would need as much quiet on stage as possible. I'm assuming the best speakers for that would be Bose L1. I'm assuming the quietest gain to still rock would be, what, 88dB? How much quieter would it be behind the speakers?

The drums would be electric and we'd all use in-ears, so I think the only peaking would come from the wall slapback and crowd noise. Thoughts?
 

RayDunzl

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#2
I measured a PA last night at 95dB in front of the speaker and 93dB behind it - and was surprised it was so similar.
The bass (lower frequencies more ominidrectional) might dominate what's being read.

Or...

If it were indoors, you're measuring the reflections of the room (assuming a less than arena-sized room).

Outdoors, the front and back of a PA stack will probably measure differently, though the bottom might still dominate.

Recently there was the opportunity for me to stand in front of (fingers firmly in ears and guessing 110-120dB) and behind (tolerable - guessing 90dB-ish) a stack (horn, mid, and subs) at an outdoor food thing. I didn't have a meter on me.
 
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DNathan

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#4
Thank you guys! So if I set my PA at 88dB on an indoor gig, even if I was standing behind the speaker it would still be about 83dB? If I used molded 26nrr plugs with embedded in-ears, I would be enduring 57dB plus the amount sent through the in-ear (which I would control). I'm guessing the whole thing plus crowd noise would amount to about 80dB. Is my thinking right? Is 88dB about what would a rock concert PA would give out?
 

RayDunzl

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#5
So if I set my PA at 88dB on an indoor gig, even if I was standing behind the speaker it would still be about 83dB?
Maybe...

If I used molded 26nrr plugs with embedded in-ears, I would be enduring 57dB plus the amount sent through the in-ear (which I would control). I'm guessing the whole thing plus crowd noise would amount to about 80dB. Is my thinking right?
Maybe again, it's hard to guess at at distance. The actual attenuation of earplugs may be somewhat variable from the specification. Your crowd may be quiet or rambunctious.

Your thinking is useful, though...

Is my thinking right? Is 88dB about what would a rock concert PA would give out?
Well...

If that's true, I'm enjoying a "rock concert" right now in my room...

upload_2018-4-19_14-6-30.png


It's not uncomfortably loud... just enjoyably so...

Extremely multitracked acapella - Marc Beacco (though with some varying minimal instrumental accompaniment)

upload_2018-4-19_14-15-14.png
 
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