when setting gains...

[bluemarvin3030]

OK, this should be an easy one. When setting gains where do you have sub level on head unit, flat (0) or maxed out? And why.

I've always had mine flat then tune amp accordingly. Just wondering which is better

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[Polar]

flat

 

[wew lad 5,000+ posts]

flat or it's max setting depending on the scale. my hu goes from 0 to 8 with 0 being off, so i set mine with it on 8

 

[nauc 10+ year member]

maxed if you want to insure no clipping. lower if you want some headroom for songs that dont have a lot of bass

 

[bluemarvin3030]

OK, how would using a bass knob factor into the equation?

 

[Umbra]

If it's a bass knob that ties into the amp it's basically adjusting gains on the fly. I'll assume you're talking about something like the PAC LC-1, which basically attenuates the RCA signal from the HU to the amp. When such a knob is all the way up it's getting roughly 100% of the signal, as if the knob weren't there. It can only reduce the signal, it can't boost it.

I have three such knobs (for the front, rear, and subs). I can adjust these values from the HU, but I like the simplicity of three physical knobs.

Set your gains with whatever settings you adjust normally at their highest setting. I don't listen to my music with a flat EQ, I go through my HU's presets (which have settings for bass/mids/treble on a scale of -8 to +8). I often use the "Powerful" EQ setting for Hip-hop/trap/dubstep, etc. which goes something like (+8 bass, +3 mids, +2 treble). There's another setting (Top 40 or Pop - something like that), that I don't use as often that has the treble at +8. I think the highest any of the presets goes to for mids is +6. So, when setting the gains I put the bass to +8, mids to +6, treble to +8.

I have bass boost off and my subwoofer set to 0 (on a scale of -15 to +15). I never turn up the subwoofer setting here. I then turn the volume up all the way (many people suggest 3/4th of max to prevent HU clipping, this is a good idea, just be sure not to stray beyond that, you'll still get max power). I use a -5dB test tones (from a test tone generator app) and an oscilloscope.

The reason I turn everything up before setting gains is that way I can do that way I can have those settings when listening to music and know it shouldn't be clipping. If you set your gains with a flat EQ and then use the EQ to boost certain bands you'll easily enter clipping territory.

 

[trumpet 5,000+ posts]

OK, how would using a bass knob factor into the equation?

Set the gain with the knob turned to its lowest setting, then turn it up with care while listening to music, treating it like a single band of EQ to adjust the bass to taste. If the amplifier is capable of making a lot more power than the sub is rated to handle you may want to skip the bass boost knob for daily listening. The pre-outs on the head unit and the amplifier should both be checked with an oscilloscope and trusted test tracks to see when clipping begins.

 

[bluemarvin3030]

Thanks everyone

 

[Jeffdachef 5,000+ posts]

If it's a bass knob that ties into the amp it's basically adjusting gains on the fly. I'll assume you're talking about something like the PAC LC-1, which basically attenuates the RCA signal from the HU to the amp. When such a knob is all the way up it's getting roughly 100% of the signal, as if the knob weren't there. It can only reduce the signal, it can't boost it.
I have three such knobs (for the front, rear, and subs). I can adjust these values from the HU, but I like the simplicity of three physical knobs.

Set your gains with whatever settings you adjust normally at their highest setting. I don't listen to my music with a flat EQ, I go through my HU's presets (which have settings for bass/mids/treble on a scale of -8 to +8). I often use the "Powerful" EQ setting for Hip-hop/trap/dubstep, etc. which goes something like (+8 bass, +3 mids, +2 treble). There's another setting (Top 40 or Pop - something like that), that I don't use as often that has the treble at +8. I think the highest any of the presets goes to for mids is +6. So, when setting the gains I put the bass to +8, mids to +6, treble to +8.

I have bass boost off and my subwoofer set to 0 (on a scale of -15 to +15). I never turn up the subwoofer setting here. I then turn the volume up all the way (many people suggest 3/4th of max to prevent HU clipping, this is a good idea, just be sure not to stray beyond that, you'll still get max power). I use a -5dB test tones (from a test tone generator app) and an oscilloscope.

The reason I turn everything up before setting gains is that way I can do that way I can have those settings when listening to music and know it shouldn't be clipping. If you set your gains with a flat EQ and then use the EQ to boost certain bands you'll easily enter clipping territory.

you really got everything backwards man. You want the bass EQ to be flat. You are literally bass signal boosting your stuff right now. You rely on the sub level to get you to proper pre-out voltage not your bass eq AKA another form of bass boost. I would not suggest turning up the volume all the way to any head unit unless you've put it on an oscilloscope and actually monitor the signal because most cheaper units clip before max volume.

 

[Umbra]

you really got everything backwards man. You want the bass EQ to be flat. You are literally bass signal boosting your stuff right now. You rely on the sub level to get you to proper pre-out voltage not your bass eq AKA another form of bass boost. I would not suggest turning up the volume all the way to any head unit unless you've put it on an oscilloscope and actually monitor the signal because most cheaper units clip before max volume.

Well that's unsettling to hear. I'll have to try it again with the subwoofer output all the way up.

So do you just listen to the EQ flat all the time?

 

[Jeffdachef 5,000+ posts]

Well that's unsettling to hear. I'll have to try it again with the subwoofer output all the way up.
So do you just listen to the EQ flat all the time?

bass EQ flat, mids and highs, you can do what you want to a certain extent. My head unit is completely different from yours so my EQ curve is rather different with 16 bands controlling individual set frequencies I normally cut frequencies where there are peaks in the sound spectrum for my loud listening custom EQ curve, I have a different one on my custom SQ curve. If I play around boosting any of the bass frequencies on the EQ, the signal starts distorting a lot quicker even though the bass sounds clean, the signal is not. Keep in mind with EQ boosts, you are adding musical information thats not supposed to be there in the first place in the recording. Thats constant with most people's setups. Thats why there's an established orthodox safe way of setting gains+head unit settings.

 

[hispls 5,000+ posts]

Avoiding any kind of "boost" "EQ", or similar on a head unit is a good way to avoid clipping from the source. To be safe, EQ should never be used to boost, but only to cut problem peaks.