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Discussion Starter · #1 ·
With as much lurking as I do, you'd think I'd have learned something by now, but it's not looking like it.

I just installed a PDX-5 and PXE-H650 last night, primarily for staging (Had a 500/5 and no processing) and to hopefully tame brutal harsh sibilance from some Seas Neo Alums. Instead I wind up with horrible noise the second you click to Acc without the HU on (factory). I have the Imprint and Amp grounded to different points, very solid there. How would you start diagnosing? Oh yeah, I'm not flush with time in the evenings, either.

Lot of cables in one general area, but it's real tight in the amp mounting location. What causes that noise? That all said, the Imprint hasn't done a thing for the sibilance and in fact it sounds considerably worse, but I'm not giving up. Tonight I'll reset the system and start again. I've read npdang and others' threads on the 650 so I know what's worked for others, just not for me thus far. And as reported, I get hardly anything from the sub through the 650 at this point and what I do get is sloppy.
 

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So, as I understand, your getting whine when the key is switched to ACC through the speakers?

Which ones, all of them, one of them?

Is the amp on at that point (I doubt it since you stated the head unit is off)...

Anytime I've had noise, its always been a ground loop somewhere. I've had cases where I needed to ground everything together, and cases where moving the ground 6 inches in either direction worked....

How do you have your head unit harness wired? This has helped some folks that get ignition (starter) whine on their vehicles....(However, only if that is your problem)


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All you can do is go step by step until its gone... Its no fun, but when its fixed, it will be worth it..
 

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Are you using the "auto sense signal power on" feature of the H650? I never got that to work right. Even with the factory head unit, I had to wire the remote turn on wire.

Also how did you set your gains on the amps?
 

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Discussion Starter · #4 ·
Well, it's the factory HU so I haven't touched that ground. I wired the remote turn on for the 650 and I have the amp gains very low, haven't tuned them up any so less than 1/3 for all three currently. Of course, the tweets scream with that much power. birthsheet has 123 x4 + 418 so I didn't want to go up too high.

Yes, hiss is clear with key to Acc, but can't localize which speaker. Seems all over somehow. Will do more testing tonight and common ground the two as well. Grounds are about 4" apart currently.
 

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Discussion Starter · #5 ·
Okay, spent the evening toying with things and yes, it was the tweet channel on the amp that was mistakenly overgained. Turned down it's fine. Now onto other things.

I tuned the H650 and adjusted gains and I think everything sounds quite good, but I'm not sure if I lucked into it or if I have things set wrong.

I can't really tell when I should up the gains on the amp and when I should up the signal gain on the 650. It wasn't real loud, but I upped the 650 aux and it's good, but I can't tell if I reversed things. Thoughts?
 

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Glad the gains solved it, could've been a lot more work :)

Make sure you raise the PXE-H650 volume using the remote to max. Just hold the vol+ button til it stops getting louder. I find this makes a huge difference in output. I'm not sure why Alpine sets the default volume so low. I like to do this before calibrating, too (when it says "Adjust Amp Gains + Xovers" on the display). Greatly increases the calibration loudness and seems to help improve calibration results IME.

If it still seems too low, you can also raise the H650 output signal by going into settings -> presets -> crossover and then increase the Front 2 levels equally left/right, as well as the sub.
 

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Discussion Starter · #7 ·
I have the vol to max on the imprint and the aux tuned pretty high, but I get distortion/clipping at 21/30 on the HU. Doesn't get as loud as one would like. Gains on the amp are higher than I think they should be, too.

Also did the 'low gain' on sub during imprint, then turn up and the bass is still wimpy. I'll play with it next week, stacked this week.
 

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If you're using the RCA inputs, check the little switch labelled "Aux Primary". It adjusts the allowable voltage range for the aux inputs. IIRC correctly its up to 2.5V with it on and only 1.5V with it off. If you have this switch incorrectly set and/or haven't set your gain structure properly, its pretty easy to clip the input--you might be clipping it and thinking you're actually clipping on your head unit or amp.
 

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Discussion Starter · #9 ·
I have the switch selected, yes. I haven't seen the green clipping on the 650, but I likely didn't set everything up correctly prior to calibration. Just set the amp gains pretty low and and aux level to maybe 10 oclock. Selected the beefiest bass curve as well. I'm sure another calibration will help.
 
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