View Single Post
Old 02-02-2012, 03:04 PM   #11
jkkyler
I bleed for HD
 

Join Date: Nov 2007
Location: Ohio
Posts: 11,562
Default

Quote:
Originally Posted by stereocraig View Post
An amplifier does not know what your SPL is, because it does not know the efficiency/ sensitivity of your speakers.

Zero db attenuation is full power. If you exceed that point, about all you're gaining, is distortion and clipping.
3db difference is half the power, not half the volume.
10db is half the volume, if measured w/ a mic and not necessarily based on what the display says.

I seriously doubt the accuracy of the display on a consumer grade piece of equipment, anyway.
I use audyssey to calibrate so why wouldn't it know since it measures spl and my amp adjusts from -80db to +15. Good point though about 10db being closer to the sound and 3db being half/double the power - I totally turfed that.

For anyone interested here is some god info:
http://www.sengpielaudio.com/calculator-levelchange.htm

for onkyo at least:
from a Onkyo manual: "A home theater system automatically calibrated by Audyssey MultEQ® XT32 will play at reference level when the master volume control is set to the 0 dB position. "
When switching volume display from "Absolute" to "Relative (THX)": "The absolute value 82 is equivalent to the relative value 0 dB."

Seems 0db is not maximum power but 85dB reference level anything above that is greater than reference level.
I have my amp limited to 0db even though it goes to +15 but I rarely get above -15db
__________________
HT- Panasonic TH-50PZ800U 1080p plasma, Panasonic PT-AX200u LCD projector, Elite Vmax Electric 100' screen, Pioneer Elite SC-71 AVR, Paradigm Titan Monitor v5 fronts, Paradigm CC-190 v6 center, Paradigm Atom Monitors v5 surrounds(x4), HSU research VTF-2 sub, HTPC/Gaming rig, Sony BDP-S550 blu-ray, Uverse HD-DVR, Roku 2

Bedroom: Insignia NS-lcd26, Samsung BDP-1400 blu-ray
Den - Vizio 20" 1080p LCD + Samsung BD-p1600


Don't believe everything you read on the internet - Albert Einstein

Last edited by jkkyler; 02-02-2012 at 03:11 PM.
jkkyler is online now   Reply With Quote