# Rockford Fosgate R1200-1D Tuning help please.



## lackdog (Feb 4, 2009)

Hi. I Have a few questions in regards to a Rockford Fosgate R1200 amp. I have been doing car audio for a long time and this amp has me scratching my head. Heres whats going on. So I want to tune this thing. I am powering a NVX VCW 15 dual 2ohm (1 ohm final)... I want the amp to put out 1200 watts. I already figured my RCA outputs from the radio is clean to 39 out of 40 volume. Play a 40hz test tone and adjust gain outpult voltage to 34.64volts. This is with the punch EQ all the way zero, EQ on radio flat. no bass boost, etc. So the math should be correct for 1200 watts. Plug the sub back in. turn it up and its not loud at all. Throw a amp clamp on the positive lead and the math come up with like 200 watts only. Now. I goto the punch eq. Turn it up to a little less than half. Now the sub is pounding like it should. Sounds awesome, But now I check the output voltage and it has obviously increased because of the punch EQ being turned up. None of the math adds up but it sounds great like that and I dont hear any audible clipping. How can this be?


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## oabeieo (Feb 22, 2015)

lackdog said:


> Hi. I Have a few questions in regards to a Rockford Fosgate R1200 amp. I have been doing car audio for a long time and this amp has me scratching my head. Heres whats going on. So I want to tune this thing. I am powering a NVX VCW 15 dual 2ohm (1 ohm final)... I want the amp to put out 1200 watts. I already figured my RCA outputs from the radio is clean to 39 out of 40 volume. Play a 40hz test tone and adjust gain outpult voltage to 34.64volts. This is with the punch EQ all the way zero, EQ on radio flat. no bass boost, etc. So the math should be correct for 1200 watts. Plug the sub back in. turn it up and its not loud at all. Throw a amp clamp on the positive lead and the math come up with like 200 watts only. Now. I goto the punch eq. Turn it up to a little less than half. Now the sub is pounding like it should. Sounds awesome, But now I check the output voltage and it has obviously increased because of the punch EQ being turned up. None of the math adds up but it sounds great like that and I dont hear any audible clipping. How can this be?



If the manual says to turn it up to 34.64V at 40hz I'm willing to bet they gave that number knowing people will use punchEq. The gain has to be down for punch eq not to saturate the signal. There bass knob is a boot controller and not a gain . 

Everyone I know grew up on Rockford amps , and knows that 12db boost at 45 is classic Rockford punch sound and what there known for. 

If you don't want to use bass knob and punch eq crank up gain a bit more and should have your 1200w. Otherwise go with it . 

If your listening to rap you may not need the bass boost , if your listening to edm or pop a bit of boost ain't bad ...


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## lackdog (Feb 4, 2009)

This amps "bass knob" isnt really a bass knob. Its a Prime amp not a Punch amp. Whatever i have my gain set to on the amp....the knob, when fully turned to max, goes to the setting i have my gain set to. And when turned all the way down is a -20db decrease in the gain. 

I can make my sub pound, but according to the math and ohms law.... its set way to high for output voltage. I do have an oscillsocope, but its like 30 years old and something stopped working on it earlier today when i was using it. 

The manual doesnt say anything about what voltage to set it too. I chose that number for a starting point and according to ohms law it should be 1200 watts at that voltage but its not.


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## oabeieo (Feb 22, 2015)

lackdog said:


> This amps "bass knob" isnt really a bass knob. Its a Prime amp not a Punch amp. Whatever i have my gain set to on the amp....the knob, when fully turned to max, goes to the setting i have my gain set to. And when turned all the way down is a -20db decrease in the gain.
> 
> I can make my sub pound, but according to the math and ohms law.... its set way to high for output voltage. I do have an oscillsocope, but its like 30 years old and something stopped working on it earlier today when i was using it.
> 
> The manual doesnt say anything about what voltage to set it too. I chose that number for a starting point and according to ohms law it should be 1200 watts at that voltage but its not.



You could try unloading that prime amp and getting a better amp. Lol

Either way punch eq works same across all RF amps , it's a boost at 45hz 
The prime amp has to have the LPF turned on for punch eq to be a bass boost, full range or HP punch eq is a wideband boost at 18khz IIRC .

I have a prime amp in my van and I hate it . I have it hooked up to be scan tweeters and some dynaudio 182s and it's complete garbage.

The T series amps are the good ones. Any way to get a deal on one of those?

Maybe the prime amps lower gain by 18db when punch eq is engaged automatically. Maybe a way to idiot proof the amp? 

Not sure that's wired tho .


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## lackdog (Feb 4, 2009)

Thanks for the reply. But let me re explain. Head unit distorts at about 39 out of 40 volume. Tested with a dd-1 that i dont have access to anymore. Hu flat eq. Turn to 39 volume. Play a 40hz tone. Dmm at speaker terminals. Bass eq zero. Adjust gain to 34.64 volts. Ohms law says that should be 1200 watts. Hook speaker back up. Adjust HU eq.....Play music at 39 volume. Bass is super weak. 

Turn bass eq to just less than halfway and the bass is flexing my doors. But ofcourse voltage has also gone up. And more than likily clipping even though it sounds great and no clipping i can tell of... 

So why does the math say it should be 1200 watts (and pounding) and it sounds quiet until i introduce bass boost?


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## oabeieo (Feb 22, 2015)

lackdog said:


> Thanks for the reply. But let me re explain. Head unit distorts at about 39 out of 40 volume. Tested with a dd-1 that i dont have access to anymore. Hu flat eq. Turn to 39 volume. Play a 40hz tone. Dmm at speaker terminals. Bass eq zero. Adjust gain to 34.64 volts. Ohms law says that should be 1200 watts. Hook speaker back up. Adjust HU eq.....Play music at 39 volume. Bass is super weak.
> 
> Turn bass eq to just less than halfway and the bass is flexing my doors. But ofcourse voltage has also gone up. And more than likily clipping even though it sounds great and no clipping i can tell of...
> 
> So why does the math say it should be 1200 watts (and pounding) and it sounds quiet until i introduce bass boost?



That is weird .

Probably has something to do with measuring voltage at output and no load on the output. 

Just a guess


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## lackdog (Feb 4, 2009)

Yah it is. And if i throw a amp clamp meter on it before the bass boost is introduced. And do the math its only like 200 watts. Thats whats making me crazy. The math isnt adding up. I know im over thinking all this but i am particular with stuff like this. When the bass boost is introduced and I clamp it its about 600 watts. I dont want to go further yet till i understand what might be going on. Im trying to figure out whats up with my O scope but its so old im sure a capacitor somewhere is dried up. Might just get a DSO nano and call it a day. Any more input is appreciated.


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