Understanding SPL Scores
04-01-2007, 08:17 AM
#1
Understanding SPL Scores
I posted this on another forum and figured it's time to post it on here too.. feel free to correct me on any parts 
I thought I would post this as many people seem confused or don't totally understand.
There are several different mic's and metering systems to measure SPL. These days the most common one is the termlab sensor system with the audio control 190 coming in a close second. There are also some older systems used - LinearX, Termlab Mic System, Audio Control 180, etc.
Each of these systems will yield a different SPL level! If I took my car and hooked up ALL of these at the same time, each would read a different number.
As stated above the most common metering system is the termlab sensor system. This system encorporates a "Box like sensor" with 2 suction cups that is attached to your windshield, then this is connected to a "sensor box" via a cat 5 network cable. The "sensor box" is then connected to a computer with a USB cable, then a program (termlab) will use the input and convert it to an easy to read number on the screen.
All dbdrag events now require the termlab sensor system. If you compete at one of these events your score will be posted on www.termpro.com. This would then be an official score. If you compete at a 2x or 3x event it will then be a certified score.
At single point IASCA events you can use any mic system you wish (normally the audiocontrol 190 or 180 is used), At CSPL events they normally use the Audiocontrol 190. At other local events any can be used.
Whenever a "pro" or seasoned competitor posts a score online it is most likely done on the termlab sensor and you can view there scores at www.termpro.com. Unfortunately after this several people often post as well stating there scores but they are normally not even done on the same metering system so you can't really compare.
Example, a competitor could hit a 155 on the termlab sensor system. On the OLD termlab mic system they could hit a 161. On the Audiocontrol 190 it could be a 158. So as you can see the same car, equipment, etc hits all different on different mics.
I hope everyone now takes this into consideration when posting scores. If you want to "prove" a score, goto a dbdrag event so it's posted on www.termpro.com. That way it'll be an official score
I thought I would post this as many people seem confused or don't totally understand.
There are several different mic's and metering systems to measure SPL. These days the most common one is the termlab sensor system with the audio control 190 coming in a close second. There are also some older systems used - LinearX, Termlab Mic System, Audio Control 180, etc.
Each of these systems will yield a different SPL level! If I took my car and hooked up ALL of these at the same time, each would read a different number.
As stated above the most common metering system is the termlab sensor system. This system encorporates a "Box like sensor" with 2 suction cups that is attached to your windshield, then this is connected to a "sensor box" via a cat 5 network cable. The "sensor box" is then connected to a computer with a USB cable, then a program (termlab) will use the input and convert it to an easy to read number on the screen.
All dbdrag events now require the termlab sensor system. If you compete at one of these events your score will be posted on www.termpro.com. This would then be an official score. If you compete at a 2x or 3x event it will then be a certified score.
At single point IASCA events you can use any mic system you wish (normally the audiocontrol 190 or 180 is used), At CSPL events they normally use the Audiocontrol 190. At other local events any can be used.
Whenever a "pro" or seasoned competitor posts a score online it is most likely done on the termlab sensor and you can view there scores at www.termpro.com. Unfortunately after this several people often post as well stating there scores but they are normally not even done on the same metering system so you can't really compare.
Example, a competitor could hit a 155 on the termlab sensor system. On the OLD termlab mic system they could hit a 161. On the Audiocontrol 190 it could be a 158. So as you can see the same car, equipment, etc hits all different on different mics.
I hope everyone now takes this into consideration when posting scores. If you want to "prove" a score, goto a dbdrag event so it's posted on www.termpro.com. That way it'll be an official score
04-01-2007, 11:46 AM
#2
Add on
I would like to add that all the older generation mics are actualy microphones that pick up sound NOT pressure. To add to your statement the Termlab and Audio Control SPL190 both with little box (termlab is a black box ) and (SPL190 silver box) are the only two official SPL sensors used to record SPL.
For Sq the mics (older style )would be more appropriate to measure peaks and different frequencies across the spectrum.
I really hate it when an old vet says i do 150's all day in my time but now if we compared their systems to what we have now with revolution in technologies with advanced engineering we are leaps ahead of what people did in the past. If we calculate what they have done before it would only be a 143 or so depending if the microphone was calibrated or not. So I hope this thread helps out for a better understanding to everyone new or old.
For Sq the mics (older style )would be more appropriate to measure peaks and different frequencies across the spectrum.
I really hate it when an old vet says i do 150's all day in my time but now if we compared their systems to what we have now with revolution in technologies with advanced engineering we are leaps ahead of what people did in the past. If we calculate what they have done before it would only be a 143 or so depending if the microphone was calibrated or not. So I hope this thread helps out for a better understanding to everyone new or old.
04-01-2007, 04:07 PM
#5
glad people are enjoying the post lol
I didn't want to go into too much detail.. just to clear up when some people think they are hitting 160's, when its really a 135..
I didn't want to go into too much detail.. just to clear up when some people think they are hitting 160's, when its really a 135..
Last edited by ChrisB; 04-01-2007 at 04:12 PM.
Thumbs up on this topic
04-03-2007, 01:32 PM
#7
Originally Posted by boombox
I would like to add that all the older generation mics are actualy microphones that pick up sound NOT pressure. To add to your statement the Termlab and Audio Control SPL190 both with little box (termlab is a black box ) and (SPL190 silver box) are the only two official SPL sensors used to record SPL.
04-03-2007, 02:09 PM
#8
Good thread man, Its nice when people share the knowledge of stuff like this rather than bash people that dont know. Im sure this will help alot of people to better understand where the real numbers come from, and why they differ so much.
04-05-2007, 10:45 AM
#9
Originally Posted by Ligeia
Not to sound like a nitpicker, but sound is pressure.
Now then scream into it and look at the score , It will say ZERO then tell everyone around you and try it and the score will still read Zero. Now you have to understand this a microphone is a unit that pick up sound ,correct !! go scream into a mic that is ran off an Audio Control unit , now you will get a score
of 120db+ If its a little silver square box with rounded corners than you are out of luck once again
Last edited by boombox; 04-05-2007 at 10:48 AM.
04-05-2007, 11:41 AM
#10
Originally Posted by boombox
just to clear this up sound is pressure but in this application is a lot different....this is what you do if you get a chance to go to a show in the future in your area look at the Termlab meter.
Now then scream into it and look at the score , It will say ZERO then tell everyone around you and try it and the score will still read Zero. Now you have to understand this a microphone is a unit that pick up sound ,correct !! go scream into a mic that is ran off an Audio Control unit , now you will get a score
of 120db+ If its a little silver square box with rounded corners than you are out of luck once again
Now then scream into it and look at the score , It will say ZERO then tell everyone around you and try it and the score will still read Zero. Now you have to understand this a microphone is a unit that pick up sound ,correct !! go scream into a mic that is ran off an Audio Control unit , now you will get a score
of 120db+ If its a little silver square box with rounded corners than you are out of luck once again
http://en.wikipedia.org/wiki/Frequency_weighting
