
Home  Forums  Rules  Articles  diyAudio Store  Gallery  Wiki  Blogs  Register  Donations  FAQ  Calendar  Search  Today's Posts  Mark Forums Read  Search 
Solid State Talk all about solid state amplification. 

Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving 

Thread Tools  Search this Thread 
20th July 2002, 06:39 PM  #1 
diyAudio Member
Join Date: Jan 2002
Location: somewhere in Australia

formula in calculating attenuation in a series configuration?
Well I was using Sheldon's calculator (http://www.quadesl.com/attenuator.html). It gives you attenuation for a particular step.
I gave the calculator the ff. values: 24 steps (I think he means positions here), 100k total resistance and total db of 64. It thens gives me several calculated resistance/attenuation for each step. Since the calculated resistor values is different from what's available, the calculated attenuation also changed. I found this site (http://www.enjoythemusic.com/steppedattenuator.htm) the gives a formula for calculating attenuation. Here's the formula Well, I calculated the db for step 23 which has 48.05 as the calculated resistance. here's the calculation: db=20*log(48.05/100000)= 66.xxdb. Sheldon's site gives be 64.xxdb. When I calculated the db for step 22 with 87.94ohm as calculated resistance. here's the calculation: db=20*log(87.94+48.05/100000)= 57.xxdb. Sheldon's site gives be 59.xxdb. I might be using an incorrect formula. So please guide me to the correct one. Thanks Jayel 
21st July 2002, 11:09 AM  #2 
Account Disabled

Can you have forgotten that
log 20 scale always compare value
to zero attenuation? While a "normal" scale have zero at nothing, the log20 have its zero at maximum output. zero attenuation. A high value is set to zero. Values below arexxdB values above are+xxdB A normal scale have no negatives, as there can not be anything that doesn't exist. Also nothing can be added to what exist. The bible says you can not take way or add something. gro 
Thread Tools  Search this Thread 


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Three 10" 4Ohm subs, wired in series or seriesparallel?  Nagamitsu  Car Audio  38  20th February 2014 12:16 AM 
Quality of Hammond 300 series power transformers compared to 200 series?  G  Tubes / Valves  10  3rd August 2012 08:32 AM 
Formula for calculating HT voltage?  LowRedMoon  Tubes / Valves  17  13th November 2006 10:12 PM 
Formula for calculating value of capacitor  klitgt  Parts  15  17th February 2005 11:38 PM 
How to put fixed attenuation between preamp and amp. Lpad or just resistor in series?  PUCK  Parts  1  19th November 2003 04:59 PM 
New To Site?  Need Help? 