Anzu Posted September 3, 2013 Report Share Posted September 3, 2013 Im new to car audio so excuse the noob question but when getting the voltage required for the gain ( V=sqrt (P*R) )should I use my amplifiers rms wattage or my subs rms wattage for power (P)? I ask this because my amp is rated for 500 watts rms and my subs are 400 watts rms, so I thought using the amps wattage might overpower the subs? I will be using a multimeter for setting the gain. Link to comment Share on other sites More sharing options...
smashedz28 Posted September 3, 2013 Report Share Posted September 3, 2013 Use your ears. Link to comment Share on other sites More sharing options...
Krakin Posted September 3, 2013 Report Share Posted September 3, 2013 Use your ears. Because ear-o-meters save subs... OP use a either an oscilloscope or an DD-1 to set you amp gains. If you have a clean signal you shouldn't be too worried about that extra power, and if you are you can just set it a little below clipping. Krakin's Home Dipole Project http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370 Krakin, are you some sort of mad scientist? I would have replied earlier, but I was measuring the output of my amp with a yardstick . . . What you hear is not the air pressure variation in itself but what has drawn your attention in the two streams of superimposed air pressure variations at your eardrums An acoustic event has dimensions of Time, Tone, Loudness and Space Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears, thus no formula can achieve a definite effect for every listener. Link to comment Share on other sites More sharing options...
CleanSierra Posted September 3, 2013 Report Share Posted September 3, 2013 Not the proper way to set gain on an amp. DD1 or an oscilloscope. A DMM can NOT determine distortion or clipped signal. Welcome to the forum, I hope you like it here Krakin, you damn Ninja 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...
goldeneye4564 Posted September 3, 2013 Report Share Posted September 3, 2013 please dont turn it all the way up is all im gonna say welcome to the forum. I RREEALLY ANGRY WIT U PHOTOBUCKET. HAD TO USE DROPBOX NOW HOLYYYYYY. Wanna ride bikes? Quote On 9/16/2017 at 3:28 AM, Jake Pace said: Oh i know how a 12v system works I did take 3 years of electronics in High school hands on and some in college and also worked on cars in college an always got A's to B's in each class. But oh well enough dealing with ppl who have probably not even lived as long as ive been into electronics! On 7/8/2013 at 4:01 AM, Banshee421 said: Do horns get low Link to comment Share on other sites More sharing options...
jarrius Posted September 4, 2013 Report Share Posted September 4, 2013 Don't use a dmm. A dd-1 or oscilloscope is the only way. Also from your original post it sounds like your running 2 subs to 1 amp if so and the subs are 400wrms a peace and you amp says it puts out 500(at what ever ohm) the. Your subs will only be recieving a MAX of 250 a peace so you are probly under powering them unless the 400rms is both subs rms as a total 2012 Chevy sonic1xSQ HDC3 12 D2RF R1200d 140 square foot of Q-Mat(soon to be installed) 140.2Db sealed on the dash with TL 142 DB sealed on the dash with another meter (was dead on with the TL at a show i was at) 141 on music. strangeduck,on 02 Jan 2014 - 01:39 AM, said: when my car spins out i just put the car in neutral, turn in the direction i want to go and pucker my asshole Link to comment Share on other sites More sharing options...
TaylorFade Posted September 4, 2013 Report Share Posted September 4, 2013 Is an O-Scope or DD-1 best? Yes. Does everyone have one? No. A DMM will get you close. I've scoped a ton of amps and I use a DMM with it so I can see what voltage it's making. All fo the quality amps I've scoped are usually pretty damn close to the SQRT method. If you don't have a scope or DD-1 available or don't care to buy one.... a DMM is fine. It's at least SOMEthing. The ol' ear o' meter won't tell you shit until you get over like 10% THD Link to comment Share on other sites More sharing options...
bbeljefe Posted September 4, 2013 Report Share Posted September 4, 2013 Share a little more information and we can probably get you really close to the proper setting without endangering your equipment. What head unit? What subs? What kind of box? What amplifier? What are you using as a source to set gain? i.e., 40 Hz tone... is it flat or -3, 5, 10dB? Also, depending on your location, there may be someone nearby with a scope or DD-1 who would be willing to help you out. And as TF said, at least you're trying to do things right and that deserves a kudos. Facebook: facebook.com/audioanarchyllc Instagram: audioanarchyllc Youtube: youtube.com/bbeljefe Link to comment Share on other sites More sharing options...
Anzu Posted September 4, 2013 Author Report Share Posted September 4, 2013 Share a little more information and we can probably get you really close to the proper setting without endangering your equipment. What head unit? What subs? What kind of box? What amplifier? What are you using as a source to set gain? i.e., 40 Hz tone... is it flat or -3, 5, 10dB? Also, depending on your location, there may be someone nearby with a scope or DD-1 who would be willing to help you out. And as TF said, at least you're trying to do things right and that deserves a kudos. Head Unit : JVC KD-R840BT http://www.crutchfield.com/p_105KDR840B/JVC-KD-R840BT.html?tp=5684 Subs/Box: mtx tne212d (probably weak subs for most but will work for me =)) http://www.crutchfield.com/p_236TNE212D/MTX-TNE212D.htmlshowAll=N&search=mtx_tne212d&skipvs=T Amplifier: thunder 500.1 http://www.crutchfield.com/p_236THND5K1/MTX-THUNDER500-1.html?showAll=N&search=thunder_500.1&skipvs=T Will be using 50hz test tone at 0dB And yeah I will try to look for someone with a scope or DD-1 near me if not i'll use the dmm and maybe set the gain a bit less than i should to be safe. Link to comment Share on other sites More sharing options...
bbeljefe Posted September 5, 2013 Report Share Posted September 5, 2013 I don't know anything about that head unit so unless someone else can chime in whose checked it, I would set the amp gain at 80% volume. For example, if the volume goes from 0-60, set it at 48. I would use a 40 Hz tone -5dB. You can go here to create and download the desired tone(s) at the desired level in lossless format. You can only create a 5 second long file, so I'd put it on repeat when setting gain. As for the subs, being in a sealed box, they can handle the extra 100 watts from the amp with no problem and probably will need it unless your interest is only in bass reinforcement. Also, if you feel you must use the bass boost, set it before you set gain and don't set it to 12dB. Only use the 6dB setting and then only if you just simply cannot get clean sounding bass from the setup without it. An example of a legitimate use for bass boost would be a setup using head unit power, that you couldn't turn the volume up very much on.... that's where bass boost can be beneficial. Although, one way to avoid using bass boost with a setup like I described is to set the amp gains at the loudest clean volume level instead of the full 80%. With mids/highs on HU power, that might be only 23-4 of 60 and if so, setting the amp at that level will remove the need for bass boost. But... if someone who doesn't know the settings (or ignores them) drives your car and cranks the volume past that set point, you risk clipping the amp pretty bad which means possible blown woofers/amp. Facebook: facebook.com/audioanarchyllc Instagram: audioanarchyllc Youtube: youtube.com/bbeljefe Link to comment Share on other sites More sharing options...
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