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View Full Version : Where Should My HU EQ Settings Be Set At When I Set My Sub Amp Gain?



heimsothe
01-26-2014, 06:27 PM
I have a Pioneer AVH-x2600bt with an 8 band EQ. I'm confused as to where I should set my EQ bands when I set the gain for my sub amp. My thought was to set them at max (12db) when I set the gain, but I've read that the EQ settings should be at 0d or flat when setting the amp gain, it has me confused. I know that my subs aren't going to be playing tones above 120hz so I was thinking the 40-200hz bands would be the ones I focus on when setting my amp. So should I; A) Set the amp gain with the EQ bands at max (12db), B) Set the amp gain with the EQ Bands at flat, or C) Set the amp gain with the Eq set to how I normally have it set? Also if I set it at flat (or anything below max for that matter) is it safe to then bump the individual bands up to get the personalized sound I want? My gut says that would cause clipping. I'm really confused hahah :laugh:

I'm using a 50hz tone to set the gain. Either 0db or -3db, not sure yet.
My HU has 8 customizable EQ bands: 40hz, 80hz, 200hz, 400hz, 1khz, 2.5khz, 8khz, 10khz.

Thanks,
Eli

Chromatic
01-26-2014, 06:48 PM
Been through this -- Can answer this with 100% confidence :)

Set your EQ flat. I'd suggest resetting the Headunit to Default/Factory settings (remove power if you need to for a minute).. Then double check your EQ, make sure it's flat.

Set your Volume on headunit to 75-80% . For example, if your headunit goes to say 40,.. set it to 30 (which would be 75%).

If you have a bass knob,.. hook it up,.. and set it to MAX.

What else.. hrmm.. Keep everything essentially at Zero (defaults) on the headunit.

You know all of this .. But then have your speaker wires OUT of the amp.. so you don't drive your self nuts setting gains -- I like to put my Pos and Negative leads from my DMM into the Pos and Neg terminal(s) of the speaker I am setting (actually lightly screw them in) -- Makes it so much easier to manipulate things without the leads falling out, etc.

Obviously, slowly turn the gains till you reach the voltage you have calculated (RMS Voltage = Sqrt(OhmsxWattage)) -- Or, just use this calculator (it's my favorite one... you input the Ohms (ie: 4) and the RMS rating you are seeking.. then click calculate and bam there's your voltage!

This is my favorite Voltage Calculator:
Voltage current resistance and electric power general basic electrical formulas calculations calculator formula calculating energy equation power watts understandimg general electrical pie chart electricity calculation - electrical voltage power form (http://www.sengpielaudio.com/calculator-ohm.htm)

After you get your gains set to proper voltage,.. THEN tweak the headunit up.. Most people agree with this method.

Something to consider though.. Many headunits have a Subwoofer "level" on them -- I'd go ahead and push that to max on the headunit before setting the sub gain -- As I've found when it's not at the max level on headunit, the RCA pre-outs for the sub tend not to push the full 4v (or whatever yours are rated at) YMMV.

Also, on the tone -- Use what tone you want.. Anything will work as long as you aren't actively attenuating it via X-over.. I used 40hz -0dB initially.. but switched to 79hz -0dB and got a better result from it (I listen to rock, no rap).. Though it really shouldn't matter.. voltage is voltage.

Here's a great set of test tones (I'm sure you have them.. but what they heck):

Realm of Excursion (http://realmofexcursion.com/downloads.htm)

Have fun with it!

heimsothe
01-26-2014, 06:57 PM
Thank you! Most of that made sense to me, but what I'm just not getting is if I set my gain with the eq flat and turn the gain up until i reach my desired voltage, wouldn't then tweaking the eq and turning the bands up cause me to clip? I'm not saying I don't trust your answer, I'm just trying to understand:D also when you say tweak, how much do you consider tweaking.... for example tweaking it from 0db flat to to +3db... or tweaking it from 0db flat to say +10db?

Chromatic
01-26-2014, 07:46 PM
Thank you! Most of that made sense to me, but what I'm just not getting is if I set my gain with the eq flat and turn the gain up until i reach my desired voltage, wouldn't then tweaking the eq and turning the bands up cause me to clip? I'm not saying I don't trust your answer, I'm just trying to understand:D also when you say tweak, how much do you consider tweaking.... for example tweaking it from 0db flat to to +3db... or tweaking it from 0db flat to say +10db?

I get your questions.. I do. Someone else can probably explain the technical side of it a bit better -- But the EQ itself is just enhancing the levels across the band from 40hz to 20,000Hz -- You bump those "levels".. but it's not the same as turning the gain knob. So no, you won't be clipping .

And, to the BEST of MY understanding -- Setting it with the EQ flat essentially is keeping you from doing so. Why? Because it's giving you ROOM to play with the eq up or down. That's why "flat" or right in the middle is the way to go. You go down on some settings in the EQ, and up on some.. you know? So it sort of balances out. I promise you won't be clipping with a flat EQ setting gains, then tweaking the EQ by ear with real music.

Personally.. My amps have plenty of power -- And this is the way I do it to be as "Sure" as I can without an O-scope or DD-1 to ensure I'm not clipping (inaudibly) -- I set the voltages.. let's say the Calculator tells me to set X speaker to 34volts (random number) -- Well I'll dial the gain up to 34volts with the DMM,.. THEN, I'll back it down half a volt to 1 volt. (That's just me) -- but that gives me ample room that I'm not pushing the speakers at their "edge" essentially.. dam.n close (as say 0.5v isn't going to make a real audible difference) -- but it gives that little headroom.

Further,.. Gains, as you know, don't go to max.. they shouldn't anyway. IE: Say you have 4V pre-outs,.. Well.. even if your amp does 70x4 -- But your 4 speakers are 80watts RMS -- Well,.. as you turn that Gain dial you aren't going to get close to 100% on the dial even when you are getting to "max" voltage and RMS wattage for the channel.

Example -- I use a PPI 900.5 (5 channel amp) -- Which at 5 channels and 4 ohms.. is rated at 70w RMS x 4 and 270w RMS x 1. I run all 4 of my mids/tweets at 70watts RMS (but back them off by 0.5v ish) -- And My gains are at 45-50% on the amp. SO many people think the gain knobs are literal volume controls and if you need to use ALL of the rated power you are going to need to turn to max.. but it's just not the way it works.

For the Sub (which the sub is rated at 300w RMS) -- The amp will push 270w RMS x1 (Rated) -- And that gain at the FULL 270watts (I didn't back the sub down at all) -- is at 55-60%. You'll see this when you are setting your gains.. Now you may end up at 70% or 25-30% on your gains.. it's just increasing that 4v pre-out (or whatever your pre-outs are).. at 12-14.4v typically to your calculated voltage which will equate to the needed Watts RMS. (Peak is of no consequence.)

This is part of the reason people argue and debate about using 0dB test tones.. -5dB test tones and so on.. due to clipping potential (how clean the signal is.. and it gets much more complicated).

but you really don't need to overthink this (Hypocritical coming from me) -- but I researched the He.ll out of this.. And I promise,.. Setting your EQ flat.. and just as I said in previous posts will net you SAFE results.

You have to work with what you have -- Most of us don't have O-scopes or DD-1's.. So we have to work with calculations and Multi-meters.. which will get you pretty darn close.. Some people don't even use a meter, they turn it up till they AUDIBLY hear clipping then back it down a touch and that's that. But if you've ever watched an O-scope.. there is clipping you have a really hard time audibly hearing.. so this method , imho, (of turning gains till Clip/distortion is audible, then back down a tad..) is one I wouldn't personally use.

Others will chime in here.. But I literally JUST did mine with this method, and everything turned out beautiful!

Setting your gains is the FUN part of the install ;)

trumpet
01-27-2014, 02:31 PM
wall of text

The gain or input sensitivity knob is only there to match the voltage of your input signal to the input section of the amplifier. There is no additional voltage created at this stage of the amplifier. It just needs to know roughly what it's working with. Is this signal strong? Is it weak? Set the gain too low and the amplifier never clips, but it may not sound loud enough. Set the gain too high and it clips often and it may clip hard with a very squared off wave.

The challenging part of understanding gain is that everything changes once you play music. A sound system can have gains set by ear by one or two trained people in a few minutes using music. In a properly designed and tuned system, there is no need to be afraid of a little clipping. If you're not clipping the transient peaks of music you're leaving good power unused. This is the #1 (http://www.caraudio.com/forums/usertag.php?do=list&action=hash&hash=1) reason to not tune for 0 clipping. If you're applying massive amounts of continuous power to speakers or subwoofers then yes, tuning to allow clipping is asking for trouble.

Chromatic
01-27-2014, 04:21 PM
What I said.

Plus "clipping is ok" in some circumstances.

Look.. It's about you, and your knowledge and setting your system. You haven't asked any more questions, so I'm going to assume you are set. Don't let different peoples opinions make you question your own firm beliefs in how things should be done. Consider them, keep what you think is rational and can back up with other research,.. throw away the rest. Part of the learning process.

Post some pics of your setup.

heimsothe
01-27-2014, 04:27 PM
Will do when I get it tweaked to my satisfaction