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mirko88

System setup - attenuation and gain overlap

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I would like to get the maximum dynamic range out of my system, with a good compromise between SPL and signal-to-noise.

 

The following ingredients are there:

Audi A6 with the OEM Audi MMI system

Rockford 3Sixty.2

PG ZX-450 4 channel amp, driving:

- Focal 3 way compo set 165KRX3

- Focal 2 way compo set 165KRX2

JL HD750/1 monoblock, driving:

- JL 12W7AE

 

I have always been told to set the maximum unclipped output level on all elements in the system first, to ensure maximum dynamic range. I have an oscilloscope available, so I can determine the exact clipping levels of OEM source unit, 3Sixty and the amps.

 

Rockford Fosgate recommends to set crossover freqs, output levels etc on the 3Sixty.

 

Here are my questions:

- When set to max unclipped levels, I will likely not have system balance and will need to attenuate. Should I attenuate on the 3Sixty as Rockford recommends, or rather on the amps?

- I'm not technical enough to understand all the fysics....if I attenuate on the 3Sixty, I decrease the output level. Does that impact the input sensitivity of the amp? And does it decrease the dynamic range?

- Is there a technical difference in using the 3Sixty vs the amp vs the remote level control of the amp to attenuate? I'm fuguring 3Sixty is output control, gain on the amp is input sensitivity contol and the remote is output control of the amp..... Perhaps they all pretty much achieve the same, but is there a preference?

 

Rockford Fosgate recommends to work with a gain overlap (using the -5dB test sine being the best compromise according to their tutorials). JL recommends just using the 0dB test sine, so no gain overlap.

It does make sense that a test track is different compared to actual music, so this could speak in favor of gain overlap.

Any advise on applying gain overlap or not?

 

Thank you for any useful information and the support to help me get the maximum out of my setup!

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Once you set up your amplifiers leave them alone. Set your levels on the 360.2. An exception might be using the remote bass knob for the subwoofer amplifier, but not if your DSP has a bass knob.

 

0 gain overlap will mean if you listen to a recording that is quieter than what you used to set the gains you will run out of "room" on the volume knob. You will want it louder and there just won't be any more power. That's where gain overlap comes into the picture. Do as RF says to do in their instructions.


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This is how i do it. Set your subwoofer gain with a DD1 using a -8db overlap track. You can make it easily with audacity. You can also just use the -10db overlap track without any problems as supplied with the DD1. You  can set the 360.3 remote to subwoofer level before this and make sure is at maximum 0db zero attenuation during gain setting. This allows attenuation of the subwoofer level. Next you get a nice recording track high quality like wav or flac with a full dymamic range of the audio spectrum something like Queen Greatest Hits. You can then listen by ear how much to attenuate the subwoofer level. For me i found that for my system i have to attenuate about -9db to get a perfect sound Quality. You can check the amount of attenuation by opening the 360 UI software after you have picked the best level on the remote. Remember this position as Good SQ.

Now if you want high SPL Bass head sound you just raise the sub level all the way up to max on the remote, for me this is like setting your gain at -8db overlap.

The DSP subwoofer attenuation remote function is almost like a variable gain overlap knob.

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