For you gain adjusting Noobs!
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Gold Member Username: Safe_crackerChicago, IL US Post Number: 2710 Registered: Jan-06 | I know there was a couple of gain adjustin Noobs here the other day wondering why when measuring volts why the output differs at different frequencies. Well I found out it has to do with crossover slope. I noticed that when I was at 35hz I got a full 78 volts but when I approached 50hz it dropped down to 67 volts and that was with all the HU settings at neutral. I measured the HU's (Pioneer 9800BT) voltage should be 5V but it was at like 2.25V, I was like WTF then I remembered someone said the sub level adjustment needs to be all the way up (+6), I turned it up and remeasured and it was at 5.15V, looked good! Now remember this all goes for the other levels also like the I-pod level adjust (+4), the BT level adjust and FM to! When they are at 0 it is around 2.25v. I measured my previous setup voltage at the amp at 35hz and I got 38V, that means I was only at like 1/2 the rms I should have been, weird... Anyhoo when the frequency goes up the crossover on the amp starts to cut the output at those frequencies also limiting the output. For the people who cannot defeat the slope just try aiming right in the middle of you HP/LP frequency settings and all should be good. Now with this said for you guys who compete, if you don't raise the bar on you LP setting and burp at close to your sutoff point you would be losing Power also? Polo... |
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Gold Member Username: JohnfiacA-ToWn, 152-153db Da... My wangers b... Post Number: 2493 Registered: Mar-06 | ^Good that you found a problem...and fixed it  I always thought the power change was just due to box rise or somthing at different freq.. that may have a little to do with it. |
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Silver Member Username: Volfenhagking160015 SSD Wangin, Shawano, Wis... USA Post Number: 642 Registered: Oct-06 | thanks polo |
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Gold Member Username: Safe_crackerChicago, IL US Post Number: 2712 Registered: Jan-06 | Can't be from box rise because if you read the instrutions on the site it says to disconnect your sub(s) from the amp(s) before putting the dmm on it. It was weird because my 9800BT didn't push its full voltage out until turned all the way up but I wanted it at 55/62 not 62/62, lol. My amps are digital with a great deal of signal processing so I was able to actually shut off the slope rate completely and found there was no difference in voltage after that at any frequency. I know some amplifiers cannot shut there crossovers off so this is why I am letting peeps know to shoot for the center frequency. I am still curious is you competing guys when burping do you actually raise your LP frequency so that your burping frequency isn't within the crossovers slope, thus reducing output power level? It isn't a lot maybe 9V but it is a loss. Polo.. |
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Platinum Member Username: BestmankindLos Angeles, CA USA Post Number: 12421 Registered: Oct-05 | mine is set at 90hz when burping a 50hz tone. you are right. i was told to set the lpf high when competing. |
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Gold Member Username: AdddisorderWest palm, Florida Post Number: 4139 Registered: Jan-06 | i just set mine on my HU and leave the amps open dont really know how that affects it but its loud enough for me |
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Gold Member Username: Nd4spd18Southeast PA Post Number: 1989 Registered: Jul-06 | That's why the directions for setting gain say to turn off all settings/adjustments on the HU...... that includes crossovers. |
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Gold Member Username: Safe_crackerChicago, IL US Post Number: 2713 Registered: Jan-06 | MS, I am not talking about the HU it also pertains to amp crossovers but not all are defeatable..Polo.. |
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Gold Member Username: Nd4spd18Southeast PA Post Number: 1996 Registered: Jul-06 | Oh, gotcha. Yeah I didn't think of that, the LPF would need for be turned up higher than the test tone frequency being used. |
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Gold Member Username: StnorrisRE SX 15, IA US Post Number: 2151 Registered: Apr-06 | hey polo, whats your aim? i got some "advanced" questions about my gain and such |
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Bronze Member Username: Big_edge_headPost Number: 79 Registered: Mar-07 | so on my pioneer HU (3800) when i set the gain i should have the bass at +6 and then turn the amps filter to all pass and set the HU hpf at 80 and the HU lpf at 80? or should i have the amp low passed at 80 also? 2 12'' AQSD2.5s pioneer 3800 HU rockford fosegate p6002 |
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Bronze Member Username: Big_edge_headPost Number: 80 Registered: Mar-07 | anyone????? please |
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Bronze Member Username: Big_edge_headPost Number: 84 Registered: Mar-07 | well???????????? |
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Gold Member Username: Nd4spd18Southeast PA Post Number: 2012 Registered: Jul-06 | Bass at 0 |
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Platinum Member Username: BestmankindLos Angeles, CA USA Post Number: 12441 Registered: Oct-05 | well according to my jl 1000/1 manual, your volume should be at 3/4 and also the bass volume should be at 3/4. after you set the gain you would put it back to 0 of course. |
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Gold Member Username: Nd4spd18Southeast PA Post Number: 2018 Registered: Jul-06 | No offense chad but are you sure you read that right. JLs online gain tutorial spells out exactly the right way to set gain, and thats not in it: http://mobile.jlaudio.com/support_pages.php?page_id=143 |
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Platinum Member Username: BestmankindLos Angeles, CA USA Post Number: 12444 Registered: Oct-05 | i see what you are saying M.S. but if you read the manual, it tells you if you have volume for bass also you should set it to 3/4 on that too. |
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Platinum Member Username: BestmankindLos Angeles, CA USA Post Number: 12445 Registered: Oct-05 | this is from the 1000/1 manual.  |
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Gold Member Username: Nd4spd18Southeast PA Post Number: 2020 Registered: Jul-06 | Alright well, I wouldn't want my amp to clip ever so I would have it all the way up when setting gain. |
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