Twice as loud ? Lets talk dB's

8 years 1 month ago #1 by DiscussBot

Decibels, dB, are a measure of loudness. Unlike other measurements, decibels are logarithmic in scale not linear.

Speed is linear, 40km/h is twice as fast 20km/h. Time is linear, 60 seconds is twice as long as 30 seconds.
Decibels arent, 80dB isnt twice as loud as 40dB. 80dB is twice as loud as 77dB !

This is how "decibels" interprets into "loudness":

+1db is 1.25x louder
+3db is 2x louder
+ 20db is 100x louder !

Click here for an excellent Wikipedia article explaining why this is so.

So to get twice as loud as your buddy you only need to gain 3dB's, but how ? Easy, you have a few options..
1. Double the power into your existing subs. Only have 500WRMS ? Get another 500WRMS !
2. Double the cone area and power. Just adding a second sub doesnt work. Why ? Because you half the power going into the first one !
3. Tune the enclosure using our nifty "SPL tuning guide"

If you have a quality amp that can handle low impedences, you can cheat a bit. Have a duel 2ohm woofer wired in series for 4ohm and 1ohm stable amp ? Parallel the coils for a 1ohm load !
Same deal with adding an extra sub, or more... load down the amp if possible and safe and voila ! More power and more cone area.

So what have we learnt ? dB's are all 2's and 3's !
2x Loud = +3dB.
2x Power = +3dB.
2x Cone = +3dB (with 2x power)
0.5x ohms = 2x Power (half the ohms load = 2x the power !)

5 years 3 weeks ago #2 by speakerrepair
so i built a sub thats got a quad 2ohm coil that gives me 0.5ohm bridged in parralel. if i build another and then series them i get 1 ohm . will this help me increase my dbs.
5 years 3 weeks ago #3 by Tezzating
Well it depends. If your amp will give you power at 0.5ohm, then introducing a second sub will halve the power both subs get and the amp will make less power at 1ohm than it will at 0.5ohm, so you will probably not see a gain.

If the amp wont give you power at 0.5ohm (goes into protection), then the 2 subs @ 1ohm will be louder as the loads lower and cone area bigger than you get with just the one.

It comes down to your amp really.

The lazy mans signature (TM)
Its Decibelcar.com Baby
Time to create page: 0.413 seconds