# Tuning a Rockford Fosgate R500X1D Amp for Subwoofers



## M_W99 (May 29, 2017)

Today I installed a MTX Terminator TNE212D loaded sub enclosure with a Rockford Fosgate R500X1D amp. Everything seems to be working as it should and all that's left is to set the amp properly. I'm using the factory head unit and have tapped into the rear stock subs for the amp input.
Many of the tuning guides out there say to turn the volume on the head until up until it distorts, back it down, then do the same with the amp gain, but that doesn't sound like a good idea in my case.
First, turning up the volume until it distorts would be extremely loud and I would fear for my speakers and ears. About 3/4 volume is as far as I can turn the head unit up comfortably. It's a premium Harmon Kardon stereo system, so I would assume that the stock stuff is already set so that it could be turned all the way up without distorting? Anyway, 3/4 volume is as much as I'm willing to go.
Second, turning the amp gain up until the sub distorts also sounds like a bad idea for the same reasons, extreme loudness and fear of damaging it.

Anyway, with all that said, I think my plan is to turn the head unit 3/4 of the way up and then increase the amp gain until it sounds comfortable.

Next comes the LPF. Being as I'm tapping into the stock subs, the LPF has already been set on them, so I'm able to turn the LPF on the sub amp all the way open unless I want to only allow frequencies lower than what the stock subs get.
Any reason I shouldn't leave the LPF on the Rockford amp all the way open like that?

Now is where I get a bit confused with the Punch EQ aka Bass Boost. There is an adjustment for it on the amp itself and a remote knob. I'd like to have everything set so that I can have the remote knob at about 1/4 to have a normal listening experience with a little added bass, and then be able to turn the knob up to make things shake. So, should I turn the Punch EQ on the amp itself to 0, set the knob to 1/4, then increase the gain until it sounds good at a normal level? Or should I set the Punch EQ on the amp itself to halfway or something, the knob to 1/4, and then adjust the gain? I guess what I'm confused about is the difference between the Punch EQ on the amp itself VS the remote knob. Do they combine together? Does the remote knob override the amp adjustment or vice versa?

Any answers I could get here would be greatly appreciated.
Thanks!


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## JH1973 (Apr 21, 2017)

Using a test tone CD or file and shooting for target voltages seems to be laughed at around here.Not sure why but I anxiously await some responses to your inquiry.


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## 1styearsi (Aug 13, 2012)

on a RF punch amp the remote over rides the amp setting and has nothing to do with the gain. again the remote punch eq is not a remote gain.i have been running punch amps for almost 20 years.
turn the remote all the way down set the gain t like 9 o'clock and when you need or want a little kick turn up the remote.


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## M_W99 (May 29, 2017)

1styearsi said:


> on a RF punch amp the remote over rides the amp setting and has nothing to do with the gain. again the remote punch eq is not a remote gain.i have been running punch amps for almost 20 years.
> turn the remote all the way down set the gain t like 9 o'clock and when you need or want a little kick turn up the remote.


Thanks, I tried this out and the results were interesting. I had previously set the gain with the remote at about 1/4 and I only had to turn the gain to about 1/4 to get some fairly flat bass going. Turning the remote up with it set like that gave things a little extra kick, but not a whole lot. Turning up the volume on the HU resulted in a lot more kick than adjusting the remote knob did.
For example, at 25% volume and the remote knob at 1/4 everything blended well, but turning up the HU to 50% or more resulted in more overpowering bass.

I re-configured the gain with the remote at 0 and had to turn the gain up to a little over 1/2 to get the same flat bass. Now turning up the remote knob really, really makes things shake.
Turning up the HU volume now maintains the bass at a more even level unlike the previous configuration.
Is this how it's supposed to function? Is there any risk or damaging something by turning the knob up all the way?

Thanks!


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## DC/Hertz (Nov 27, 2011)

That remote is bass boost. Unhook and throw it away.


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## M_W99 (May 29, 2017)

DC/Hertz said:


> That remote is bass boost. Unhook and throw it away.


How would I adjust the amount of bass on the fly then? The EQ on the Head Unit?


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## DC/Hertz (Nov 27, 2011)

You don't need to adjust on the fly. Set it and forget it. 
All that knob does is boost a limited bandwidth. 3db of boost is asking the amp to double its power. If it doesn't have to give its clipping. Straight up square wave. Toasted speakers quick.


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## M_W99 (May 29, 2017)

DC/Hertz said:


> You don't need to adjust on the fly. Set it and forget it.
> All that knob does is boost a limited bandwidth. 3db of boost is asking the amp to double its power. If it doesn't have to give its clipping. Straight up square wave. Toasted speakers quick.


Well there are times where I don't want things shaking, and there are times that I do, and I don't really want to have to reach back in the trunk every time I want to turn it up or down.


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## DC/Hertz (Nov 27, 2011)

That's not how that knob works. It's not a gain remote. 
You will want an inline bass remote like PAC has. It goes with the RCAs. Super easy and it will do what you want.


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## DC/Hertz (Nov 27, 2011)

PAC LC-1 Remote Amplifier Level Controller https://www.amazon.com/dp/B0002J226O/ref=cm_sw_r_cp_api_zTGnzb783C8M2


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## M_W99 (May 29, 2017)

Found this on the Rockford Fosgate product page:

On-board Punch EQ with +18dB boost @ 45Hz

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Remote Controls: Punch Level Control:
When connected is linked to "gain control" to provide remote output level 

According to that, it seems to me that the dial on the amp itself is the bass boost, and that the remote knob is a remote gain? Or perhaps I'm misunderstanding something...


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## DC/Hertz (Nov 27, 2011)

Yeah you are reading it right. I guess the primes are different. 
This is the one I thought it was. The powers come with it. 
45hz boost. PEQX3 - Remote Punch EQ for 3 Amps (2007+) | Rockford Fosgate®


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## M_W99 (May 29, 2017)

Ah, ok. Well then it would appear that the remote knob is indeed a remote gain control. Knowing that, I'll have to play around with it some more.


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## 1styearsi (Aug 13, 2012)

DC/Hertz said:


> That's not how that knob works. It's not a gain remote.
> You will want an inline bass remote like PAC has. It goes with the RCAs. Super easy and it will do what you want.


there is nothing wrong with setting the bass on the radio flat or neg and rocking the knob.
the punch bass eq made the old punch45 famous .
On-board Punch EQ with +18dB boost @ 45Hz
Remote PLC (Punch Level Control)----not a gain!!


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## DC/Hertz (Nov 27, 2011)

Yeah that's 45hz centered bass boost. It's bad.


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## 1styearsi (Aug 13, 2012)

oops i am wrong:surprised: it seems it is a remote gain after all sorry if i miss spoke.
to each his own......M_W99 what kind of music do you listen to???
i disagree with most everyone here on bass boost.
i think your listening taste kind of matters.
boost has it's place for instance i don't really use it if i am playing rap but when i'm rocking some lynyrd skynyrd it's nice to have.
i also use the accubass on my lc7i.i have 2 bass knobs OMG! i guess i'm a rebel LOL.:gossip:
i feel it gives me more control over my sound not more ability to shake my mirror.


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## DC/Hertz (Nov 27, 2011)

3db of boost is the same as asking the amplifier to supply 2x the power. And it's only at 45hz. If the amplifier doesnt have more power to give its clipping the output. 
Considering we already have a lot of cabin gain around 45hz all it does is sound peaky and possible burn up drivers from clipping.


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## M_W99 (May 29, 2017)

1styearsi said:


> oops i am wrong:surprised: it seems it is a remote gain after all sorry if i miss spoke.
> to each his own......M_W99 what kind of music do you listen to???
> i disagree with most everyone here on bass boost.
> i think your listening taste kind of matters.
> ...


EDM, pop, occasional rap, rock, etc. I might play around with the bass boost but I've mostly heard negative things about it (and not just from here).


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## M_W99 (May 29, 2017)

I contacted Rockford Fosgate and they confirmed that it is a gain control and that the proper way to set the gain on the amp is to either turn the knob all the way up or unplug it during setup.


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## resret (Jul 21, 2018)

M_W99 said:


> I contacted Rockford Fosgate and they confirmed that it is a gain control and that the proper way to set the gain on the amp is to either turn the knob all the way up or unplug it during setup.


Sorry to bump an older thread here, but I need to ask this question. Rocksford told you that you can unplug it during setup. Does this mean once you get the gain at the correct level for the RMS output you want, you can safely connect the knob and use any level on it (Within reason for what is being played)? My amp is certified at 641 watts and I multimetered it in at 29.15 volts with a 50hz test tone @ a measured 1.7ohms for 500 watts. Sub is a JL 12w3v3-2.


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## WilliamS (Oct 1, 2016)

The remote is a gain control, if you unhook its essentially the same as the amp turned all the way up. Set your volume to max before distortion, turn the gain knob to 75-80% range, and set you gains.

Remember if you are at low volume it wont add up to more volume unless you set the gain at the lower volume level.


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