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View Full Version : how to test voltage at headunit?



2002XLT
08-10-2007, 05:35 PM
im curious if this might be the reason why my sub is not as loud as i would like. I really dont like turning up the volume as much as i have to at this point to get the voltage i need at my amp, i have to turn it up to 21, and i really dont want to turn it above 18, also this is with my amps gains pretty much all the way up, so im curious if sincei have a 2V headunit, that might be my problem? And im not sure how to match up my amp with my headunit since there is a setting for input level, which goes from 0db up to 24 db, not sure how that translates inot the voltage, because it says its .5 - 8.5V ready. Im thinking i might need a line driver to boost the input level? or am i way off?

wesl56
08-10-2007, 05:38 PM
hey on that alpine, under the subwoofer level settings, do you have that all the way up? the deck only puts out full preout voltage to the woofer when that setting is at max, and the voltage just goes down as you adjust it from there

95BlackGA
08-10-2007, 05:39 PM
A line driver/new headunit with higher preamp voltage WOULD help you. This is my problem. I have a cheap headunit with low headunit out put voltage, so my gain has to be up if I want it to be loud, luckily, for now, I don't want to be loud. Once I get a new headunit, or line driver, I will be.

95BlackGA
08-10-2007, 05:41 PM
I didn't even see what headunit you have. But I agree with the statement above mine.

2002XLT
08-10-2007, 05:43 PM
ya it goes up to +15, and i have to max the HU out, and the gains on my amp just to see around 44 volts at the sub..

wesl56
08-10-2007, 05:43 PM
9853 in his siggy

2002XLT
08-10-2007, 05:43 PM
and max the volume to 21, if i go to 22 i get up into the 54-55 volt area, which is too much.

2002XLT
08-10-2007, 05:44 PM
soo line driver would help? Id really like to keep the volume at about 18 max right now, since i have stock speakers and they start to distort any higher.

2002XLT
08-10-2007, 05:58 PM
where did you guys go....

2002XLT
08-10-2007, 06:09 PM
............

SRim23
08-10-2007, 06:29 PM
do you have the media xpander on? i have the 9855 and with it on the volume is quieter and after like 19 on the volume it stops getting louder all together. try turning it off and see how it sounds. when everything is tuned correctly everything sounds better anyway

2002XLT
08-10-2007, 06:33 PM
well in all honesty, im having some trouble getting the hu tuned as well, got any tips on what i should be setting all the levels to? ill check the media xpander, not sure if its off or not.

2002XLT
08-10-2007, 07:00 PM
soo line driver?? or no....

trunks9_us
08-11-2007, 10:37 AM
i would get a line driver not sure your alpine makes one but it not look into phoenix gold.

dipitydoo
08-11-2007, 11:41 AM
What's the maximum volume setting on the HU? Something like mid to high 30's maybe, if I remember correctly? Why do you not want to go past 18? The volume range is there on your HU, use it. Judging by the fact that you get close to your max desired output at vol number 21, I suggest you turn your gain down, if only to minimize noise and gain a more subtle change in volume per click. If you don't have audible noise already, a line driver won't audibly help.

2002XLT
08-11-2007, 11:48 AM
after 18 my stock speakers distort. Max setting on hu is 35.

2002XLT
08-11-2007, 11:49 AM
oh, and anything above 21 and the voltage on my amp (gain) starts going down, not up.

dipitydoo
08-11-2007, 07:49 PM
after 18 my stock speakers distort. Max setting on hu is 35.

Do you have a highpass crossover on the stocks? If not, that's one reason for the distortion. Another could be too much power, if driven by an amp.

dipitydoo
08-11-2007, 08:06 PM
You should turn your gain down. A line driver will definitely not be of use in this case. In fact, with most modern decks, they will be of no use for typical setups.

fratch69
08-11-2007, 08:21 PM
I have an Alpine 9857 and my system didint come alive until i added an Audio Control 3.1. Stupid 2v preouts. Get the 3.1 it worked wonders for me :)

wvufootball
08-11-2007, 08:27 PM
make sure media xpander is off. at least for me the media xpander really cut off the midbass. And i run a 9853 and i dont have a problem with the 2volts.

dipitydoo
08-11-2007, 10:32 PM
Before you start buying new things, I would diagnose the problem properly first. I re-read your original post, you seem to be having problems with output from your sub? Could be several things. One, you might be expecting too much out of it. Two, there may be setting on your HU that might be misadjusted. Doublecheck all signal processing on the HU. Also, you said the stock speakers distort. Are you saying that you can't turn the volume up any higher than 18 or 21 because of this? If so, you need to high pass your mids. Better yet, get an amp that has a built-in crossover for them. 1kw to a 15" sub with stock speakers and HU power is a bit much. High passing the mids will limit bass frequencies from overdriving the small mids, therefore, allowing you to turn up the volume higher without distortion. Whatever is the case, a line driver isn't your solution.