Axiom Home Page Forums General Discussion Technical Questions Room size

I need to ask a question regarding room size that has me puzzled a bit.

If I am playing something at a certain sound volume, how does the room size fit into the equation? More specifically, if I am playing my receiver at -10 with my Epic system... in a small room, in a large room, in a concert hall.... what is the difference?

Is there a difference in the work that the reciever goes through by being in a different sized room, cinsidering the exact same system played at the exact same sound level?

Or does everyone just consider the fact that if you are in a smaller room you will just play everything at a reduced level?

Inverse square law? *Minus reflections? *Factor in headroom? *Add the point where the tweets melt?

It's a starting point!

In reply to:

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More specifically, if I am playing my receiver at -10 with my Epic system

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The dB scale on your receiver is a relative scale. You're not playing at -10dB SPL (which would be an audio black hole), you're playing at the full power of the amplifier (or whatever the 0dB reference is) minus 10dB. There's a lot of confusion between dBu, dBv, dBm, and dB SPL. The first two are voltage measurements, dBm is a measurement of power and dB SPL is a measurement of Sound Pressure Level (what most people think the only definition of decibels is). So what your display is showing you is not the sound pressure in the room at your listening position, but rather an electrical measurement of it's amp circuit. Make sense?

Bren R.

Hey Bren, would that mean that if I have the volume dial on my HK set at 0db, it would mean that this reciever is playing at it's full potential? Am I understanding this right?

I don't know the importance of "0"db(gotta find out)but it must be important to THX as they use it as some kind of standard in determining something or other!

Uh...Anybody??

I guess it really depends on the receiver - anyone with experience across the board with different manufacturers know if this blanket statement is true?

Do all manufacturers "top out" their volume controls at 0dB (my Yamaha does - do others "slide" the scale up into the positive numbers to make you feel like you're getting something for nothing?) and do all manufacturers use full amp power as reference? And if so, where do they draw the line at "full power" without driving an amp into a clipping state during peaks?

Something that I've never had to look into in home audio.

Bren R.

I went through the HK manual and couldn't find the explaination, asked a friend and he told me he thought it was just as you said above a relative number given by the manufacturer to determine the volume level for that particular piece of equipment...he owns the Yamaha 2500 btw.

The relative part makes sense. But what does each manufacturer use as the 0dB reference that the setting is relative to? If it's full-out, everything the amp's got, then care should be taken to never run the receiver near that or it will be forced into a clipping situation during peaks in program material.

Bren R.

My Onkyo goes to +10 on the relative scale. Pretty silly, unless there's a turbocharger in there.

ok, the question here really got sidetracked. Forget about anything I mentioned about -10. Think Spinal Tap and say I'm playing my stereo at 11 (but it goes to 11) or any sound level for that matter.....

Given the exact same system, played at the exact same sound level in a small room, a large room and a concert hall... what is the difference?