Calculator that generates SPL output with sensitivity, power, number of cabs, surface loading, and listening distance as inputs. Perhaps not 100% accurate but should be helpful in doing "the math" on what to build:
Edit: Read the rest of the thread before clicking.
http://myhometheater.homestead.com/splcalculator.html
How Loud Will It Go? Speaker Power/Volume calculator.
- BrentEvans
- Posts: 3044
- Joined: Thu Oct 09, 2008 10:38 am
- Location: Salisbury, NC
How Loud Will It Go? Speaker Power/Volume calculator.
Last edited by BrentEvans on Fri Jul 31, 2009 12:15 am, edited 1 time in total.
99% of the time, things that aren't already being done aren't being done because they don't work. The other 1% is split evenly between fools and geniuses.
- Bill Fitzmaurice
- Site Admin
- Posts: 28645
- Joined: Tue May 02, 2006 5:59 pm
Re: How Loud Will It Go? Speaker Power/Volume calculator.
It's wrong. It only gives 3dB boost per boundary instead of 6dB, and it totally misidentifies 'room gain', which is not the same as boundary loading and is not accounted for in the calcs.
- BrentEvans
- Posts: 3044
- Joined: Thu Oct 09, 2008 10:38 am
- Location: Salisbury, NC
Re: How Loud Will It Go? Speaker Power/Volume calculator.
Ok, peace offering for not checking the math . Here it is, fixed for 6db per surface (and stripped of all the unneccessary crap):
http://splcalculator.110mb.com/
If the math isn't right, I'll do my best to edit.
http://splcalculator.110mb.com/
If the math isn't right, I'll do my best to edit.
99% of the time, things that aren't already being done aren't being done because they don't work. The other 1% is split evenly between fools and geniuses.
Re: How Loud Will It Go? Speaker Power/Volume calculator.
There is a estimation for dispersion, that needs explanation or correction.
Dispersion as per Olson:
"Acoustic dispersion is the separation of a complex sound wave into its various frequency components, due to variation with frequency, or its equivalent, of the wave velocity of the medium."
Dispersion is separation not attenuation and varies with frequency and the medium involved.
Attenuation of sound over distance also has to take into consideration the frequency and the qualities of the medium.
Dispersion as per Olson:
"Acoustic dispersion is the separation of a complex sound wave into its various frequency components, due to variation with frequency, or its equivalent, of the wave velocity of the medium."
Dispersion is separation not attenuation and varies with frequency and the medium involved.
Attenuation of sound over distance also has to take into consideration the frequency and the qualities of the medium.
- Bill Fitzmaurice
- Site Admin
- Posts: 28645
- Joined: Tue May 02, 2006 5:59 pm
Re: How Loud Will It Go? Speaker Power/Volume calculator.
+1. Dispersion would impact off-axis SPL, not axial. The calc shown is axial response corrected for distance.Sydney wrote:There is a estimation for dispersion, that needs explanation or correction.
- BrentEvans
- Posts: 3044
- Joined: Thu Oct 09, 2008 10:38 am
- Location: Salisbury, NC
Re: How Loud Will It Go? Speaker Power/Volume calculator.
Poor wording, I agree. I'll update to use the above language. Anything else I can do to make it more correct?Bill Fitzmaurice wrote:+1. Dispersion would impact off-axis SPL, not axial. The calc shown is axial response corrected for distance.Sydney wrote:There is a estimation for dispersion, that needs explanation or correction.
Edit: changed a few of the descriptions for accuracy.
99% of the time, things that aren't already being done aren't being done because they don't work. The other 1% is split evenly between fools and geniuses.
- Bill Fitzmaurice
- Site Admin
- Posts: 28645
- Joined: Tue May 02, 2006 5:59 pm
Re: How Loud Will It Go? Speaker Power/Volume calculator.
Note that it's only 100% accurate outdoors. Indoors the permutations created by multiple boundaries change everything. Also, boundary loading is reduced by 6dB above the baffle step frequency, so to be safe you only consider boundaries below 500 Hz.BrentEvans wrote:Anything else I can do to make it more correct?
Re: How Loud Will It Go? Speaker Power/Volume calculator.
FYI: See Set2 on this .xls spreadsheet
http://www.dni-inc.com/things-here/misc ... _v1.12.xls
As Mr. Fitzmaurice just stated succinctly, a calculator has to have it's variables included and qualified.
Even outdoors has factors that cause deviations from pure theoretical assumptions.
http://www.dni-inc.com/things-here/misc ... _v1.12.xls
As Mr. Fitzmaurice just stated succinctly, a calculator has to have it's variables included and qualified.
Even outdoors has factors that cause deviations from pure theoretical assumptions.
-
- Posts: 5740
- Joined: Thu May 04, 2006 10:58 am
- Location: Sacramento, Moderator/Licensed BF Builder
- Contact:
Re: How Loud Will It Go? Speaker Power/Volume calculator.
Most calculated responses are only good at small signal levels. Hence, 1w/1m.
Above this, all bets are off. Too many variables, i.e. power compession.
Indoors, a measurement rig is mandatory. Anything else is a SWAG.
Above this, all bets are off. Too many variables, i.e. power compession.
Indoors, a measurement rig is mandatory. Anything else is a SWAG.
My biggest worry is that when I'm dead and gone, my wife will sell my toys for what I said I paid for them.