Question on Setting amplifier gains

[BroncosNeverDie]

Hello,

I have a question about setting gains. I have a 94 Bronco with an aftermarket 200A alternator. I have the 7" Denovo Audio Anarchy midbass woofers in the doors powered by a Alpine GM-D8604, Alpine hiend 28mm tweeters powered by another GM-D8604 and a 1Ohm 12" 750W Image Dynamics subwoofer in a ported box in the back powered by a 1200W Rockford Fosgate amp. A JL Audio Bluetooth receiver gets signals from my phone and feeds into a JL Audio TWK88.

Anyway, I tried resetting the gains this weekend because last time I did so I somewhat rushed it. But I am encountering odd problems, specifically clipping at very low levels. For the subwoofer, I set the "Bass Control" of the Fosgate amp all the way up, the volume knob of the TWK88 about 75% up and the phone volume 75%. I have done my due diligence and made sure my phone and the TWK88 do NOT clip at these levels, so the 0dB 40Hz tone is clean coming into the amplifier. But on the other side of the amp, with Gain set to lowest setting and all the other things (Bass boost) turned all the way down, I get clipping. Look at the waveform below. I was a bit baffled. The install is good, last time I checked there was a 0.2 Ohm drop between the rear ground connection and the battery negative terminal. I had to lower the volume to about 66% and the bass control knob of the fosgate to about 50% to get a clean waveform. Again, this is all at Gain 1. How is this possible? Should I be doing this with -5dB or -10dB test tones? Similar problems occured for the two Alpines. Clipping very early and I was using 0dB 1kHz, 4kHz and 8kHz tones. The sound is clean when I play music but it's several magnitudes quieter than before, when I set my gains quickly.

Any help appreciated!

EDIT: I just reread the Rockford Fosgate Prime 1200W amp manual and noticed that the "Bass Control" I have on my dash is this:

REMOTE PUNCH LEVEL CONTROL
When connected, the “Gain Control” is linked and allows you to remotely control the output level of the amplifier from the dash or center console.

So is this basically a remote gain control? If so then there's just two gain controls working against each other. How do I go about setting the actual gain knob on the amplifier itself?

BND

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[mat3833 10+ year member]

If I'm not mistaken you need to treat the bass control on the amp as the gain and the remote controls the gain from zero up to that point.

Matt

 

[Bassthoven]

So is this basically a remote gain control? If so then there's just two gain controls working against each other. How do I go about setting the actual gain knob on the amplifier itself?

I personally would probably set the remote knob to half it’s range (so you can turn the sub down or up based on how the song was mixed) and then start from the minimum level on the onboard gain and turn up until it’s where it needs to be.

I’m also new to car audio, but I do live sound for a living, and we usually use pink noise (not test tones) to balance out a system: run pink noise from your source, then balance the various amp gains to get as flat a response as possible, then use dsp (peq, geq, dynamic eqs) to take you the rest of the way.

 

[macsdad 10+ year member]

If it is a true gain knob, then set your gain with the knob at the max setting, then it is just an attenuator as it is meant to be. With that being said, again if it is a true gain knob, wherever your amps gain is set at, the knob will not surpass that setting.

 

[Jeremy11]

Hello,

I have a question about setting gains. I have a 94 Bronco with an aftermarket 200A alternator. I have the 7" Denovo Audio Anarchy midbass woofers in the doors powered by a Alpine GM-D8604, Alpine hiend 28mm tweeters powered by another GM-D8604 and a 1Ohm 12" 750W Image Dynamics subwoofer in a ported box in the back powered by a 1200W Rockford Fosgate amp. A JL Audio Bluetooth receiver gets signals from my phone and feeds into a JL Audio TWK88.

Anyway, I tried resetting the gains this weekend because last time I did so I somewhat rushed it. But I am encountering odd problems, specifically clipping at very low levels. For the subwoofer, I set the "Bass Control" of the Fosgate amp all the way up, the volume knob of the TWK88 about 75% up and the phone volume 75%. I have done my due diligence and made sure my phone and the TWK88 do NOT clip at these levels, so the 0dB 40Hz tone is clean coming into the amplifier. But on the other side of the amp, with Gain set to lowest setting and all the other things (Bass boost) turned all the way down, I get clipping. Look at the waveform below. I was a bit baffled. The install is good, last time I checked there was a 0.2 Ohm drop between the rear ground connection and the battery negative terminal. I had to lower the volume to about 66% and the bass control knob of the fosgate to about 50% to get a clean waveform. Again, this is all at Gain 1. How is this possible? Should I be doing this with -5dB or -10dB test tones? Similar problems occured for the two Alpines. Clipping very early and I was using 0dB 1kHz, 4kHz and 8kHz tones. The sound is clean when I play music but it's several magnitudes quieter than before, when I set my gains quickly.

Any help appreciated!

EDIT: I just reread the Rockford Fosgate Prime 1200W amp manual and noticed that the "Bass Control" I have on my dash is this:

REMOTE PUNCH LEVEL CONTROL
When connected, the “Gain Control” is linked and allows you to remotely control the output level of the amplifier from the dash or center console.

So is this basically a remote gain control? If so then there's just two gain controls working against each other. How do I go about setting the actual gain knob on the amplifier itself?

BND

How did you find the clipping point on your phone?