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Discussion Starter · #1 ·
This is my 'backup' headunit. Figured I'd get the oscope and DMM out to test the headunit preout voltage at it's clipping point. I used a 1khz test one at 0dB.

Results:
To my surprise, this headunit doesn't clip, or come even close seemingly, even at full volume (35/35).
At that point, measured preout voltage is 4.14V. Pretty dang nice.

Pics:















And, yes, those are Dog the Bounty Hunter DVDs. :D
 

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Hey I got ones of thems to go wth my H700...to bad it won't spit out my CD...not happy that I'm gonna have to send it back to Alpine for a fixin...
 

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Discussion Starter · #4 ·
see, all that work to get an h700 so it'll match your 7996 and now look. :eek:


FWIW, my 7996 works just fine. It's the least that could happen for me after the 7990 showed up with a busted cd mech. Been over a month and am still waiting on parts from Japan. :mad:
 

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that's the way it was designed .... 4V preouts with no clipping at full volume
 

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Discussion Starter · #6 ·
What happens when you boost that area with EQ or tone controls?
Don't really have many options on this deck regarding tuning, so you're limited to bass/treble tuning. 10khz is the lowest you can go on the treble.


Boost 10khz +7dB:
No clipping.
Preout voltage increases to 4.32V

Turning on MX only (user EQ flat):
Still no clipping.
Preout voltage goes to 4.67V
 

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Don't really have many options on this deck regarding tuning, so you're limited to bass/treble tuning. 10khz is the lowest you can go on the treble.


Boost 10khz +7dB:
No clipping.
Preout voltage increases to 4.32V

Turning on MX only (user EQ flat):
Still no clipping.
Preout voltage goes to 4.67V
That's pretty good, I guess 4 volts for that deck actually means "4 volts".
 

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Discussion Starter · #11 ·
No idea. Was actually thinking about posting that question. If there's a way to somehow check THD from a preout like that? No idea, man. Wish I knew. Would've done it already. ;)
 

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No idea. Was actually thinking about posting that question. If there's a way to somehow check THD from a preout like that? No idea, man. Wish I knew. Would've done it already. ;)
Sure is, Rightmark audio analyzer (free) with a soundcard that has at least as good an input stage as the equipment you are testing. your rig should be adequate for the task

You burn a cd with the two track used by it, set you output from the headunit to match the needed amount of the software and let her rip.

You will however be limited to a certain volume setting before you clip the software so you'll need a high quality potentiometer (or a preamp voltage divider network to attenuate the max 4 volt output to a 1 volt max (i think) for that test. Or you can run the output from the head to a processor that accepts whatever strength signal and always outputs the same voltage through use of its volume control.
 

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Sure is, Rightmark audio analyzer (free) with a soundcard that has at least as good an input stage as the equipment you are testing. your rig should be adequate for the task

You burn a cd with the two track used by it, set you output from the headunit to match the needed amount of the software and let her rip.

You will however be limited to a certain volume setting before you clip the software so you'll need a high quality potentiometer (or a preamp voltage divider network to attenuate the max 4 volt output to a 1 volt max (i think) for that test. Or you can run the output from the head to a processor that accepts whatever strength signal and always outputs the same voltage through use of its volume control.
Just DL'd this....thanks for that T3sn4f2

Heres the link:

RightMark Audio Analyzer 6.1.0 Free Download RMAA suite is designed for testing quality of analog and digital paths of any audio devices, be it a sound card, an MP3 player, a 33573

Now I will get a good soundcard so I can play with this.

I've used RAE 2.0 but this one looks much better.
 

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Discussion Starter · #14 ·
i've got the m-audio mobile pre... that should suffice I would think.

might tinker with it this weekend if I get a chance. coolness.
 

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These older Alpines were the shiz...

I wonder how my newer DVA-9860 would fair.
 

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I'd love to see how the FR plots look at different head unit volume settings. See if there is any EQ or volume dependent EQ they don't mention in the manual or in single FR plot reviews.

One thing to note, the signals used for testing are -3dB and not full scale. Can't remember why they do this but everything I've seen tested uses that default setting.
 

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I'd love to see how the FR plots look at different head unit volume settings. See if there is any EQ or volume dependent EQ they don't mention in the manual or in single FR plot reviews.
QUOTE]

ditto!!!!!
 

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