snafu Posted September 6, 2013 Report Share Posted September 6, 2013 OK, here's one that'll get you thinking. Hell, it's had me thinking since Electronics 101 as a Junior in HIgh School (1985 - 1986 that was . . . ) The number .707 comes up often in math (It's actually .7071067811 ... but .707 will do for this brain twister). IE - consider the following formulas, and their relationship to one another: Power = Voltage2 / Resistance RMS Power = (Voltage x .707)2 / Resistance Now, when you go and square .707, you get .500 which is pretty cool in and of itself, but then when you consider that RMS Power = Peak Power / 2, you also discover that you're really dealing with the same amount of "power" . . . just discussing it differently. For example, let's say that we have an amplifier that can deliver 10 Volts AC (IE - a sine wave that measures 10 Volts at it's Peak) into a 2 Ohm resistive load. Let's solve for Power and RMS Power: Power = (10 Volts)2 / 2 Ohms Power = 100 / 2 Power = 50 Watts RMS Power = (10 Volts x .707)2 / 2 Ohms RMS Power = (7.07)2 / 2 Ohms RMS Power = 50 / 2 Ohms RMS Power = 25 Watts Therefore, we've proved that 50 Watts "Peak" = 25 Watts RMS. There are numerous mathematical equations at which the result is .707 . . . who can name a few? Quote Tony Candela - SMD Sales & Marketing Email me at [email protected] to learn about becoming an SMD Partner! Link to comment Share on other sites More sharing options...
CleanSierra Posted September 6, 2013 Report Share Posted September 6, 2013 Qtc= 1/square root of 2 for the Butterworth response. Quote Im not the one you want to try to troll. Just a fyi for you. Link to comment Share on other sites More sharing options...
snafu Posted September 6, 2013 Author Report Share Posted September 6, 2013 Indeed. There are MANY more examples. Quote Tony Candela - SMD Sales & Marketing Email me at [email protected] to learn about becoming an SMD Partner! Link to comment Share on other sites More sharing options...
SnowDrifter Posted September 6, 2013 Report Share Posted September 6, 2013 A 3db decrease in power ends up with the output voltage being reduced by a factor of 707. Useful trick to know when setting crossover points. It's also the conversion factor from peak to peak (square wave) voltage to RMS(sine wave) voltage. Works great for setting amps with a DMM. Measure the rail voltage, do the conversion, adjust the gain accordingly, boom done. It's a bit more accurate then trying to use the traditional DMM method IMO. Especially in amps that are underrated and trying to adjust the gain to a preset number will end up with clipping in an attempt to get the desired output voltage Quote ~~~~~~~~SAY NO TO PHOTOBUCKET~~~~~~~~ Snow's DD-1 tracks here: https://www.stevemeadedesigns.com/board/topic/167433-snows-dd-1-tracks/ My take on OFC vs CCA: https://www.stevemeadedesigns.com/board/topic/110381-things-that-piss-you-off-in-the-car-audio-world/?do=findComment&comment=2461444 Link to comment Share on other sites More sharing options...
reg93f150 Posted September 6, 2013 Report Share Posted September 6, 2013 The sine of 45 degrees is .707 Quote ALL CREDIT TO XX1 FOR DC BANNER down rpping vanderbilt. 30 miles from victoria. i own the 3rd loudest setup here out of 3. but i did put together all 3 setups strapping 2 amps together ? like bolting them next together? using bungy cables to hold them down? or wiring separate amps to each sub Link to comment Share on other sites More sharing options...
snafu Posted September 6, 2013 Author Report Share Posted September 6, 2013 and the cosine . . . Quote Tony Candela - SMD Sales & Marketing Email me at [email protected] to learn about becoming an SMD Partner! Link to comment Share on other sites More sharing options...
Omega5002 Posted September 6, 2013 Report Share Posted September 6, 2013 Qtc of .707 is a magic number for best response in a sealed enclosure.Like cleansiera mentioned, it's also the Second-Order Butterworth, which is for max flat amplitude response. Quote 2003 Kia Sorento Team Subsonic LowsTeam Bassin' on a Budget2016 Rebuild Under Construction Best score: 150.2 at 40hz (3k, 2 Custom HDC3 15's) Usaci style(door open, in the kick) Link to comment Share on other sites More sharing options...
jandsaudio Posted September 6, 2013 Report Share Posted September 6, 2013 Wtf did I just read? I need to get on here more often and read up on some of this stuff lol I'm lost Quote Link to comment Share on other sites More sharing options...
reg93f150 Posted September 6, 2013 Report Share Posted September 6, 2013 and the cosine . . . you sir are correct i love reading your stuff, even though it takes me a while and a couple hundred re reads to understand it.. haha Quote ALL CREDIT TO XX1 FOR DC BANNER down rpping vanderbilt. 30 miles from victoria. i own the 3rd loudest setup here out of 3. but i did put together all 3 setups strapping 2 amps together ? like bolting them next together? using bungy cables to hold them down? or wiring separate amps to each sub Link to comment Share on other sites More sharing options...
CleanSierra Posted September 6, 2013 Report Share Posted September 6, 2013 and the cosine . . . Mind=blown. It's also .707 Quote Im not the one you want to try to troll. Just a fyi for you. Link to comment Share on other sites More sharing options...
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