jnasty Posted March 4, 2019 Report Share Posted March 4, 2019 Hey guys so I just picked up the dd1 and set my gains to distortion.. amp is an arc audio 4000se. I also had my dmm hooked up as well and got a reading of 72.8v before distortion. does this mean my amp puts out 5,299w at 1ohm?? Is this a cheap way to "dyno" my amp? I'm highly doubtful this amp makes that much power but HELL, I'll be happy if it does.. Vehicle: 2002 Ford Escape Electrical: 275A Singer, 160ah XS/Yinlong lithium, 2,000farad XS Supercaps Head Unit: Apple iPad Hi-Res Passthrough Topping d10s Speakers: {ACTIVE} - (4) Arc Audio RS 6.0, (2) Arc Audio RS 4.0 & (2) Arc Audio RS 1.0 Sub Stage: (2) TC Sounds LMS Ultra 5400 18" Amplifiers: ARC Audio - (4)4200SE(comp modded, (2)4000SE Processing: Helix DSP Pro W/ Dash Mounted Director Link to comment Share on other sites More sharing options...
k58.cross Posted March 5, 2019 Report Share Posted March 5, 2019 I can give you a half (ass) answer. I should have realized this point earlier, but sadly I did not... The output of your amp is AC, so when you try to do calculations like V^2/Z or I^2*Z, you're getting VA not Watts. See my attachment. You need to know the power factor of the amp output to get a true measure of real power (Watts). Then W = V*I*pf or (V^2*pf)/Z or I^2*Z*pf, but only at the point in time you measured. If that measurement is fairly constant over a range of time in a given condition, then the average power in that condition is what you calculated. But we aren't given power factor are we?? How are you all getting real power measurements besides for buying an expensive ass PQA? Link to comment Share on other sites More sharing options...
k58.cross Posted March 5, 2019 Report Share Posted March 5, 2019 I do want to add one thing though: The lower the harmonic distortion of the amp, the better the power factor is, and thus the more the real power part dominates the measurement you're taking with a (hopefully true RMS) DMM. You can get an idea of real power delivered using a good DMM on a good amp, but it will always be less. On a reactive load like a speaker, you will always have some reactive component, and every amp will have some measure of harmonic distortion. Link to comment Share on other sites More sharing options...
Dragonsyph Posted March 6, 2019 Report Share Posted March 6, 2019 Was wondering this too, would clamping the speaker wire and getting an amp reading then multiply that by voltage going into amp to get watt output the sub is seeing? ♦ Sundown NSV4 18" + Sundown SALT-4 Baby ♦ MechMan Elite 370a + XS3100 - XP3000 ♦ SHCA 1/0 OFC(blue) + SMD Fuse Holders(blue) ♦ Pioneer AVH-2440NEX + SHCA Pro RCA Link to comment Share on other sites More sharing options...
Smoove Posted March 6, 2019 Report Share Posted March 6, 2019 If you can find one, get an AMM-1 if you want to clamp unless you have access to a TL with clamps 2 Team Fi 15's v1 2 DD M5's 970amps of Alt 6th order blowthroughThe truck Blowthrough build : http://www.stevemeadedesigns.com/board/topic/155555-smooves-1996-chevy-ext-cab-c1500-slow-build/The 350z build : http://www.stevemeadedesigns.com/board/topic/170694-smooves-2003-nissan-350z/ My FB page https://www.facebook.com/pages/Smooves-Car-Audio-and-performance/719746144805343 Team Fi Audio http://www.ficaraudio.com/ Link to comment Share on other sites More sharing options...
k58.cross Posted March 6, 2019 Report Share Posted March 6, 2019 1 minute ago, Smoove said: If you can find one, get an AMM-1 if you want to clamp unless you have access to a TL with clamps Do the AMM-1 and Termlab both take power factor into account so you get a real power measurement? Link to comment Share on other sites More sharing options...
Smoove Posted March 6, 2019 Report Share Posted March 6, 2019 No, they are just realtime clamps. both can even capture what your rising to. 2 Team Fi 15's v1 2 DD M5's 970amps of Alt 6th order blowthroughThe truck Blowthrough build : http://www.stevemeadedesigns.com/board/topic/155555-smooves-1996-chevy-ext-cab-c1500-slow-build/The 350z build : http://www.stevemeadedesigns.com/board/topic/170694-smooves-2003-nissan-350z/ My FB page https://www.facebook.com/pages/Smooves-Car-Audio-and-performance/719746144805343 Team Fi Audio http://www.ficaraudio.com/ Link to comment Share on other sites More sharing options...
k58.cross Posted March 6, 2019 Report Share Posted March 6, 2019 Well looking at AMM-1 website, it does say power factor and real power measurement. But I was talking with a colleague and it turns out you can make it super easy by using a scope. Probe the voltage and use a clamp probe on the current, then take a reading at the frequency and volume of interest. Instantaneous power will be the voltage at one point in time multiplied by the current at the same point in time. This is useful because we know power draw varies with frequency, so we're only looking at very specific operating points anyway (worst case power draw). Doing this eliminates the need to know power factor. As a side I think you can calc the power factor by cosine of the phase between the voltage and current waveforms. I'm pretty sure that will vary by frequency too though. One more point. Clamping power is one thing, but the actual SPL is the real measure of your system. Power draw is typically lower when SPL is highest because the SPL is coming from mechanical and enclosure resonances as opposed to high power draw. Link to comment Share on other sites More sharing options...
Dragonsyph Posted March 11, 2019 Report Share Posted March 11, 2019 I wish the AMM 1 wasent 400 bucks, would be nice device to have. ♦ Sundown NSV4 18" + Sundown SALT-4 Baby ♦ MechMan Elite 370a + XS3100 - XP3000 ♦ SHCA 1/0 OFC(blue) + SMD Fuse Holders(blue) ♦ Pioneer AVH-2440NEX + SHCA Pro RCA Link to comment Share on other sites More sharing options...
k58.cross Posted March 11, 2019 Report Share Posted March 11, 2019 8 hours ago, Dragonsyph said: I wish the AMM 1 wasent 400 bucks, would be nice device to have. Same as most of the SMD products, they aren't insanely expensive but are a bit pricier than they should be. They're marketed towards people that want the most-used features in an easy to understand interface and don't mind dropping the extra cash. You can pick up a Rigol scope and a BNC current clamp for 400 and have the added benefit of seeing the signal on the screen, among other things. Just need to have some electronics knowledge to calculate things. Link to comment Share on other sites More sharing options...
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