quakecitystudio Posted June 11, 2008 Report Share Posted June 11, 2008 (edited) Do you guys remember Chris Lewis when he worked for AutoSound and Security. He had an article that stated how one could calculate his or her estimated SPL based on amp wattage and woofer output at 1w/m. It was an estimation because vehicular modifications or box setups would make it more complex. I remember trying to email him, to let him know that his chart was a bit flawed, but he never responded back. It was as if he disapperaed off of the face of the planet. I still have the article: For those of you that are not sure of the article it is called "The SPL Channel" in Auto Sound & Security/ August 1997. "PART TWO: How I spent my Summer Vacation Blowing Stuff Up." From the article: Edited June 16, 2008 by quakecitystudio Quote Bass Music Producer • Photographer • Graphic Designer -------------- Deep Sector Boom... Link to comment Share on other sites More sharing options...
Boon Posted June 12, 2008 Report Share Posted June 12, 2008 Do you guys remember Chris Lewis when he worked for AutoSound and Security. He had an article that stated how one could calculate his or her estimated SPL based on amp wattage and woofer output at 1w/m. It was an estimation because vehicular modifications or box setups would make it more complex. I remember trying to email him, to let him know that his chart was a bit flawed, but he never responded back. It was as if he disapperaed off of the face of the planet. I still have the article, with my version of the charts... A wild, wild, wild, completely infeasible estimation? 8" Sub we tested 500wrms In a van, 2 4" aeroports = 133dB In a tiny Ford Hatch, 1 4" aeroport, bit of box tweaking = 142dB Of course it was flawed, he probably didn't email back because he got 10000 other emails about it being flawed. Quote 10.x volts fo' life! Link to comment Share on other sites More sharing options...
tommyk90 Posted June 14, 2008 Report Share Posted June 14, 2008 (edited) Those charts are completely worthless. Most people can't get a 140 out of a type-r 10, I got my truck up to a 151. All of your threads suck. Edited June 14, 2008 by tommyk90 Quote Team B2, Team Audiotechnix, Team Kicker, Team XS Power, Team Sundown, Team Maxxsonics, Team DD2008 Bassrace 130-139.9 Regional and National Champion2006, 2007, 2009, 2010 and 2012 MECA Champion (S1, SR1, S2, S3, S4, DB1) -1 DD 9510F + 2 Sundown SAZ2500's @ .7 ohm strapped=154.2 headrest, 129.2 driveby-2 DD 9510F's + 2 Sundown SAZ2500's @ 1 ohm strapped=154.0 headrest-1 DD 9512F + 2 Sundown SAZ2500's @ 1 ohm strapped=153.5 headrest, 131.1 Driveby -2 DD 9512F + 2 B2 Zero1's @ .5 strapped= 157.0 headrest, 158.0 outlaw-1 Sundown SA-8 + 2 MB Quart 2000's=148.8 headrest, 150.6 outlaw Link to comment Share on other sites More sharing options...
quakecitystudio Posted June 16, 2008 Author Report Share Posted June 16, 2008 (edited) All of your threads suck. Why make such a comment like that? Do you see me harassing you about your threads? No, so let it go. Edited June 16, 2008 by quakecitystudio Quote Bass Music Producer • Photographer • Graphic Designer -------------- Deep Sector Boom... Link to comment Share on other sites More sharing options...
quakecitystudio Posted June 16, 2008 Author Report Share Posted June 16, 2008 We must understand that his calculations are based on the 1w/m outside of the vehicle, with all other variables constant. The only considerations being the woorfer, and the wattage, and an efficiency constant of 116.6. Now, here's where I have questions: Where did he get 116.6 db and how is it a measurement of efficiency? Also, how did he determine the dbs of each ratio number? There is no standard formula, like saying since 1:1 is 0 and 2:1 is twice as 1:1 then 2:1 will = 3 and since 4:1 is 2x2 then 4:1= 6dbs meaning twice the output= 3+ dbs. But, after that it's off the map... Here's what I did on his chart: a comparison of ratio to ratio:(middle numbers are the difference between ratios) 1:1 = 0 3 2:1 = 3 1.7 3:1 = 4.7 1.3 4:1 = 6 1 5:1 = 7 .8 6:1 = 7.8 2.5 7:1 = 8.5 .5 8:1 = 9 .5 9:1 = 9.5 .5 10:1 = 10 There isn't a pattern, and the only thing that stands is that 4:1 is twice more than 2:1, but no value for 1:1 since 2:1 is twice more than 1:1. Quote Bass Music Producer • Photographer • Graphic Designer -------------- Deep Sector Boom... Link to comment Share on other sites More sharing options...
quakecitystudio Posted June 16, 2008 Author Report Share Posted June 16, 2008 Here is my version: 1:1 = 1.125 2:1 = 2.25 3:1 = 3.375 4:1 = 4.5 5:1 = 5.625 6:1 = 6.750 7:1 = 7.875 8:1 = 9 9:1 = 10.125 10:1 = 11.25 or if 1:1 must equal zero: 1:1 = 0 2:1 = 3 3:1 = 4.5 4:1 = 6 5:1 = 7.5 6:1 = 9 7:1 = 10.5 8:1 = 12 9:1 = 13.5 10:1 = 15 Quote Bass Music Producer • Photographer • Graphic Designer -------------- Deep Sector Boom... Link to comment Share on other sites More sharing options...
quakecitystudio Posted June 16, 2008 Author Report Share Posted June 16, 2008 As an example We will use Chicken's caddy: actual 160 db on termlab (and door open) 16,000 w on the subs (2,000/sub) 18" BTL 93.7 db 1w/m *Now this calculation is outside the vehicle at 1w/m* The spl of one woofer at 2000 w: woofer's efficiency + wattage given to woofer = spl of one woofer 93.7 + 33 (Based on Chris Lewis Scale) = 126.7 db for one woofer at 1m or 39.37 inches from mic. SPL of given wattage if sound system was efficient at 1 meter: 16,000 w = (2)((10)(10)(10) = Chris's table = 3+9+10+10+10=42 42+116.6(efficiency standard)= 158.6 db at 1w/m So you can see that Chris's numbers are pretty close. Quote Bass Music Producer • Photographer • Graphic Designer -------------- Deep Sector Boom... Link to comment Share on other sites More sharing options...
tommyk90 Posted June 17, 2008 Report Share Posted June 17, 2008 (edited) Why make such a comment like that? Do you see me harassing you about your threads? No, so let it go. I'm a jerk. And, if you can't take a hint, nobody gives a damn about these numbers. The severe lack of replies should tell you that. In all seriousness, there's no reason to even bother wasting time trying to figure out some mathematical formula. For some cars it may be close, and for others it could be drastically off. That's all part of the SPL game. Instead of trying to figure out equations you should spend time building and testing to see what works and what doesn't. Edited June 17, 2008 by tommyk90 Quote Team B2, Team Audiotechnix, Team Kicker, Team XS Power, Team Sundown, Team Maxxsonics, Team DD2008 Bassrace 130-139.9 Regional and National Champion2006, 2007, 2009, 2010 and 2012 MECA Champion (S1, SR1, S2, S3, S4, DB1) -1 DD 9510F + 2 Sundown SAZ2500's @ .7 ohm strapped=154.2 headrest, 129.2 driveby-2 DD 9510F's + 2 Sundown SAZ2500's @ 1 ohm strapped=154.0 headrest-1 DD 9512F + 2 Sundown SAZ2500's @ 1 ohm strapped=153.5 headrest, 131.1 Driveby -2 DD 9512F + 2 B2 Zero1's @ .5 strapped= 157.0 headrest, 158.0 outlaw-1 Sundown SA-8 + 2 MB Quart 2000's=148.8 headrest, 150.6 outlaw Link to comment Share on other sites More sharing options...
Boon Posted June 17, 2008 Report Share Posted June 17, 2008 That whole article just smacked of failure to me. The sheer difference you can get in dB by changing pathetic little things means any mathematic modelling of a system is fairly meaningless. For SPL it is only real world testing that matters. His statement that concrete and lexan are pointless seems woefully ignorant. Go tell Alan Dante that. Also tell me how Dante does 180.1 with 'only' 28000w to a single 18" woofer 28000w = 10x2800 = 10x10x280 = 10x10x10x28 = 10x10x10x2x14 = 10x10x10x2x2x7 So chart numbers: Chris: 10 + 10 + 10 + 3 + 3 + 8.5 = 44.5 44.5 + 116.6 = 161.1 = Failure Your numbers: 11.25 + 11.25 + 11.25 + 2.25 + 2.25 + 7.875 = 46.125 46.126 + 116.6 = 162.725 = Failure Have you ever actually done an SPL build? You would probably know little things like 'maths never equals real world' and that totally seperating the rear wave (usually) does NOT make a car loud - as well as amazing facts like simple cars = loud cars, take one look at the Euro street scores and that would become very apparent. Quote 10.x volts fo' life! Link to comment Share on other sites More sharing options...
Big P Posted June 17, 2008 Report Share Posted June 17, 2008 I'm a jerk.And, if you can't take a hint, nobody gives a damn about these numbers. The severe lack of replies should tell you that. In all seriousness, there's no reason to even bother wasting time trying to figure out some mathematical formula. For some cars it may be close, and for others it could be drastically off. That's all part of the SPL game. Instead of trying to figure out equations you should spend time building and testing to see what works and what doesn't. Why are you being such a dick? Its really uncalled for. Quote Link to comment Share on other sites More sharing options...
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