Checking gain adjustment

[audioholic 5,000+ posts]

Thats what I dont understand. The formula doest can what pre out voltage you have

That equation is simply quantifying/verifying amplifier output, where your gain knob ends up to reach that voltage is based on the h/u signal voltage. I understand what you are saying, the equation somewhat bypasses your need to know signal voltage, but that doesn't mean your h/u has nothing to do with setting your amplifier gains.

 

[LosIsATool 5,000+ posts]

I mean it does play a role. Its sending the signal.

 

[grocery getter 10+ year member]

I have my lpf set to about 80hz, I dont set it higher cause I don't like the higher bass notes. Subsonic is about 40hz, thats about where my box is tuned to. I'll play with the 2 and see where it gets me on speaker output voltage, thanks for the advise. About gain, my understanding. Is to set it to the hu so your amp doesn't start sending a clipping signal. I know the max speaker output volts would be the highest I would want to set the gain by checking with a dmm. An oscope is suppose to be the best way to set cause you can actually see at what point the amps starts clipping. Now, my hu says 2v max to the outputs. But thats with all levels turned up, I could barely reach half vol without distorting the highs and mids. So would it be beneficial to get a line driver to set out put volts to amp higher and not have hu levels so high? Would it help me get max volt output from amp with out having to turn gain up so high? I should of commented earlier that when my hu levels are all at max my amp output volts can reach 28.28, but the hu amp is distorting highs and mids way early in vol. Line driver? It sounds good how I have it set now, but only getting 20v on amp output. That only equates to 200watts. I paid for 400watts, I want to use all of it. Plus my sub is rated 200rms to 600rms watts.

 

[bubbagumper6 5,000+ posts]

I mean it does play a role. Its sending the signal.

The gain knob's final position depends on the HU pre-out voltage. Granted you don't need to know the voltage to set the gains, but saying it has nothing to do with the gains is in no way correct.

Think of it this way, if your HU preout voltage is very low, like 1V, then when you set your gains with a DMM it's going to be on the high side, but if your preout voltage is 6V, the gain will end up being a lot lower. Understand? You don't need to know it to set the gains but it does have an affect.

 

[Haunz 10+ year member]

what does 2v/45k with the ohm sign mean?

It means your deck's RCA outputs can output 2V into 45 thousand ohms.

 

[vaiboy 10+ year member]

I have my lpf set to about 80hz, I dont set it higher cause I don't like the higher bass notes. Subsonic is about 40hz, thats about where my box is tuned to. I'll play with the 2 and see where it gets me on speaker output voltage, thanks for the advise. About gain, my understanding. Is to set it to the hu so your amp doesn't start sending a clipping signal. I know the max speaker output volts would be the highest I would want to set the gain by checking with a dmm. An oscope is suppose to be the best way to set cause you can actually see at what point the amps starts clipping. Now, my hu says 2v max to the outputs. But thats with all levels turned up, I could barely reach half vol without distorting the highs and mids. So would it be beneficial to get a line driver to set out put volts to amp higher and not have hu levels so high? Would it help me get max volt output from amp with out having to turn gain up so high? I should of commented earlier that when my hu levels are all at max my amp output volts can reach 28.28, but the hu amp is distorting highs and mids way early in vol. Line driver? It sounds good how I have it set now, but only getting 20v on amp output. That only equates to 200watts. I paid for 400watts, I want to use all of it. Plus my sub is rated 200rms to 600rms watts.

The filter settings I suggested were only to set the gain, but you should have your subsonic 5-10 hz below the boxes tuned frequency. Those dials aren't very precise so it's possible to have them set to a frequency other than what you intended. If either of the filters are set too close to the test tone frequency it will reduce the output, so to remove that possibility while you set the gains turn them to a position where you are certain they aren't the problem.

Since you are using the head unit for mids and highs. Set the volume to the highest level you can before the speakers start to distort and use that level to set your gains. Don't get too caught up on the lack of a full 2v signal since that is a peak measurement anyway. Your real limiting factor is the head unit amp or your mid/high speakers, the best solution would be a second amplifier and possibly a set of components. If your mids and highs were properly filtered and able to be driven at the same level as your subs you would easily get your 400 watts. A line driver will get you a 400 watt output, but it will most likely introduce more noise to the system too, it's more of a band-aid.

 

[grocery getter 10+ year member]

Yeah I thought about an amp for the highs and mids. I know I could better match everything. This jvc arsenal is a little monster for what it is. Didnt know jvc had it em.