Why do some volume controls start at -80db or..?

My Audia starts at -90. If you like things that start at zero let me recommend the Kelvin temperature scale; starts at absolute zero. Water boils at 373 K etc.

What Elizabeth said. On volume controls that use plus/minus, 0 is zero gain. Which is to say, at zero grain, the input signal from the source is effectively untouched by the volume pot. Now, for your average digital source, zero gain is real hot and damn loud. Thus, the majority of the usable volume range will be in the "minus" realm, in which the volume control is operating passively to attenuate (or apply negative gain) to the input signal. When you get into the positive numbers, the volume control is using a mini amplification stage to "add gain" to the input level and boost it above zero gain. (A "passive" volume control will only go negative, and have no amplification stage or ability to add gain). So, volume controls that display +/- are actually providing useful info that ones that read 0 to X do not -- ie, where zero gain lives and the volume control is doing the least/nothing to alter the signal. FWIW, I prefer the 0 to X range myself, but the other is perfectly legit and useful.

So who are the engineers placating? The customer or themselves? On occasion when I load up some music I'll set the volume to say "50" on my KCT preamp and walk away while it gets ready to play. Simple enough. On the Yamaha receiver setting to "-24.5" as an average setting for atarters..? "Simple things for simple minds" as my wife always says. Seems to be usually directed my direction.
-JD

Mine goes to 11!

On level scales that indicate zero full open, '0' is NOT no gain, it's FULL gain...as much as the device was designed to create. The minus portion of the scale is that number of deciBels BELOW FULL GAIN.

Such a scale is quite useful in displaying just how much of the Voltage gain built into our preamps/amps/receivers that we DON'T use.
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The reason for the differance between the two is the Krell is for 2 channel and the Yamaha is for HT. I think as I do not have manuals on your equipment. Your Yamaha has a calabrate mode so you can set the volume, distance and envelope of your speakers. You calabrate your speakers so all of them will be the same at zero volume. The zero setting is really between 75-85db for home theater. When the volume is set to zero you are at the recommended volume for movies. It is meant as a referance point. Your Krell I do not think has a calabrate mode.
I think 75db is recommended for home theater and 85 db for commercial theaters.
IMHO

This has been a really useful thread. My HT amp goes from -80 to 0 and I have asked this question elsewhere and have always come up with a queer look of puzzlement from my would-be respondents. Thank you all for the insight.

Interesting responses, most times the numbers on a volume control or attenuater mean little. Keep in mind, attenuate simple means a reduction of amplitude of oscillation, so removing the volume control from the circuit would give you full power.

BTW my Meridian G68 can display volume as -86 to +12,1 to 99 & no display.

So, you are not really turing the sound UP, you are turning it LESS DOWN?