Difference in db between 1v & 2v output?

Moderator: JackD201

Difference in db between 1v & 2v output?

Postby Oldfogey » Sun Jan 09, 2005 9:56 am

Hi all,

I'd like to ask what the difference in output, measured in decibels, would be between digital frontends (CD players, transport/DACs) outputting 1 volt, and the standard 2 volts, respectively.

I remember reading somewhere that the figure would be 10db difference, just want to confirm this.

Thanks in advance,

OF
Oldfogey
Moderator
 
Posts: 613
Joined: Mon May 19, 2003 5:04 pm

Postby JackD201 » Sun Jan 09, 2005 10:53 am

Hi Oldfogey,

here's the formula.

NdB = 20 log V1/V2

Hope this helps.
User avatar
JackD201
Immortal
 
Posts: 10024
Joined: Sat Oct 09, 2004 12:10 am
Location: Bozania

Postby Hyperion » Sun Jan 09, 2005 11:23 am

In theory, the difference for every doubling of voltage (say 1V to 2V) is 6 dB.

This is not however equivalent to the actual change in SPL loudness that one would hear from the speakers since speakers (as well as our ears) are not dynamically linear.
User avatar
Hyperion
Moderator
 
Posts: 1910
Joined: Thu Jan 23, 2003 11:57 pm

?

Postby Oldfogey » Sun Jan 09, 2005 2:00 pm

Jack, Hyperion,

Thanks a lot, guys!!

OF
Oldfogey
Moderator
 
Posts: 613
Joined: Mon May 19, 2003 5:04 pm

Postby rtsyrtsy » Sun Jan 09, 2005 4:45 pm

I remember reading in Oldfoey's Guide to Hi-End Audio that doubling the power means a 3dm increase. Is that for power amplifiers power only or does it apply to this as well?

Sorry, technically-inept question. :D
User avatar
rtsyrtsy
Moderator
 
Posts: 3908
Joined: Tue Jan 28, 2003 5:25 am

Postby joe3rp » Sun Jan 09, 2005 6:50 pm

I don't think db rating for voltage in the front end/low level equipment (CDP, LINE PRE-AMP) is applicable. db only applies when the electrical signal signal is converted to mechanical energy (sound pressure)...which is usually between the power amp / speaker (or even headphones).
joe3rp
Fanatic
Fanatic
 
Posts: 1473
Joined: Tue Jan 28, 2003 7:58 pm

Postby JackD201 » Sun Aug 06, 2006 9:40 pm

Mods, Please move to Tech Archives

Thanks!

Jack
User avatar
JackD201
Immortal
 
Posts: 10024
Joined: Sat Oct 09, 2004 12:10 am
Location: Bozania

Postby tony » Sun Aug 13, 2006 11:19 am

I remember reading in Oldfoey's Guide to Hi-End Audio that doubling the power means a 3dm increase. Is that for power amplifiers power only or does it apply to this as well?



yes, to double the power(3db), voltage must increase by 40%, so a voltage increase of 100% reperesents 6db.

log of 2 = 0.3, so that a change from 1 to 2 in voltage equals = 20 x 0.3 or 6db.
User avatar
tony
Fanatic
Fanatic
 
Posts: 1882
Joined: Tue Jun 24, 2003 7:18 am
Location: Pasig City....


Return to Technical Archives

Who is online

Users browsing this forum: No registered users and 1 guest

cron