TEST TONE HELP = 40Hz-5db VS. 40Hz-0db for tuning AMP

[missionman]

Hello Audio Community, 

 

Can someone clarify 2 questions I have?

 

#1 

why am I using a 40Hz-5db test tone as opposed to a normal 40Hz-0db tone? 

I understand -5db is better but I have no idea why.

 

#2 

do I use this -5db formula for tuning both my sub (27.5Hz sub test tone) and gains (40Hz -5db gains test tone) when tuning with voltmeter?

I only have a 27.5Hz test tone for my sub. Is this ok?

 

THANK YOU FOR THE HELP! I dont have an oscilloscope, therefore im using a higher quality DDM that measures tighter voltage accuracy.

 

-Jacob

 

 

 

 

Edited May 7 by missionman
type-o's

[Kyblack76]

Google Overlap. 

Cheers

[SnowDrifter]

1: So ya know how sometimes, a TV show might be quiet, so you turn the volume up only to have the commercials know you out of your seat? That's kind of the same say. -5db is like... Turning up the volume just enough so you can hear the show, but now enough that the commercials are super loud. 0db is like not turning up the volume at all. The commercials are at a fine volume, but you can't hear the show at all!

2: Tuning with a multi meter? ehh? You have a DD-1, why the 2-step?