spl

[Crafty]

lo

[WaterHond]

Too much spl?

[Robert_E]

Too much: a great way to kill off your ability to hear those nasty high frequencies. 

[Crafty]

? lol
i was going to type something, then my kid must have gotten hold of my phone
was running around yesterday like a chicken without a head. had a party for a 3 Year old at my house.
any ways...

sorry. here is the actual question

How is spl measured?
I have downloaded an iphone application that measures the sound, and keeps an eye on the frequency.
this application gives more or less the same reading as what the receiver shows.
ie, -20 db is where i would watch a standard action movie. then the application would report about -20 db

if I use music, and push it to about -10 db the roof is ratteling and the windows feels like it is going to shake off the putty that keeps it in place. some simpler bass songs i would even push to -5

but obviously this reading is not Spl. i would imagine that should be closer to 100 or 110 db more or less?
so what is the reading on the receiver that goes from -81 to +20?
And what iphone app can i use to measure real spl.

[audiomuze]

Dunno, but at 100-110 dB you're well into permanent hearing damage territory

[Batman]

From what I understand from owning a low wattage valve amp and 90db sensitive speakers. Every time you double the input power it goes up 3db. That's what a human would perceive as an being louder when you increase the volume knob. And my 20 watt valve on my 200 watt speakers gets really loud at -20db.

I'm trying to research the matter. There are various reference points on the web for db e.g. 110db may be a rock concert.

[Batman]

Also the size of the room, natural room resonance, etc will affect db imo.

If you actually look at it this way, you could have the same amp but use two different sensitivity speakers and they both will have different spl readings at the same volume/power setting.

[KenMasters]

so what is the reading on the receiver that goes from -81 to +20?
And what iphone app can i use to measure real spl.

Assuming you've used the auto setup, 0db would be reference level (should be 75db), then obviously the "minus" figures show you how much below that you are and "plus" how much above.

[Crafty]

Assuming you've used the auto setup, 0db would be reference level (should be 75db), then obviously the "minus" figures show you how much below that you are and "plus" how much above.

ah! this makes sense! But can 60 or 65 really make the tiles on my roof move and the windows rattle?
thanks.
I'm still due to do the auto setup. I have not mounted my rear speakers yet. need brackets etc.
My stereo set gets priority at this stage

[Robert_E]

Assuming you've used the auto setup, 0db would be reference level (should be 75db), then obviously the "minus" figures show you how much below that you are and "plus" how much above.

If you use the avr's pink noise to calibrate your speaker's level at 75dBC the spl level of that pink noise is in fact 30dB BELOW peak dolby reference levels. Peak dolby reference levels for the mains are 105dB for the speaker channels and 115dB for the LFE channel. 

On a THX certified avr the volume display on the avr is relative to this dolby reference level with 0dB on the display being reference when calibrated.

I don't even do sound demo's at reference levels and it's earth shaking at 5dB below. 

[Robert_E]

That's only applicable to movie sound-tracks. With music or other sources you have no way of knowing what peak SPL levels your system is producing without actually measuring it with an spl meter.

[KenMasters]

ah! this makes sense! But can 60 or 65 really make the tiles on my roof move and the windows rattle?
thanks.
I'm still due to do the auto setup. I have not mounted my rear speakers yet. need brackets etc.

Without having used the auto setup, there's no way of knowing what volume 0 actually is. Once you've used the auto setup the receiver will set 0 at 75db at the measurement position.

[Batman]

Whoa! My NAD don't have that. I like it the way it is

[soundadv]

Without having used the auto setup, there's no way of knowing what volume 0 actually is. Once you've used the auto setup the receiver will set 0 at 75db at the measurement position.

Ken,will that be a std on all AVR's?

[Crafty]

Too much spl?

ps, no such thing as too much... or at least i have not found my limit yet...