i have a pioneer avic z2 head unit that is accompanied by a pair of alpine mrd-m1005, powering aa pair of 4 ohm kicker 15" L7s. i read somwhere that you want to match the volts coming from head unit to the amp. ex i z2 puts out 4 volts, i can set the amp at 4 volts, but when i turn it to the next lower 2.5 volts it pounds way harder and so on when set at 1.5 volts. but am i wrong thinking that this is damaging my subs. is it bad idea to not match the volt gains?
Your question portrays some typical assumptions and is exactly why setting the gain properly is so important for a successful install. You cannot rely on published data when surmising voltage output, and you cannot rely on the markings around a gain knob to tell where to set the gain position. So, it doesn't matter that the head unit is rated to deliver a 4 volt output, nor does it matter that the amplifier's gain knob has markings around it.
The fact is, the deck may not put out a full 4 volt output in a clean, non-clipping state at any frequency. And it certainly wouldn't be putting out its highest rated voltage at the low sub freqs. So disregard output voltage ratings and set your sights on learning how to set the gains.
Use the Google search of the12volt.com found on this page to find how to properly set the gain on the amps. This search used only the word "gain". You can also type "setting gain" or "gains" or other phrases to get some different hits, but you'll come to see that the actual gain-setting process has been discussed many times. In no authoritative statement will you see that you should read the manual to find out deck voltage output or that you should set gain position according to markings. Here's an earlier thread on the subject that includes some other threads that I linked to get you started on the right path.
I suggest you use the listening procedure to find clipping levels at both the head unit and the amplifier. It doesn't rely whatsoever on equipment ratings or position markings, and you can do it with your eyes closed. And, you do not need to use a voltmeter to set gains this way. You should, however, use recorded sine wave tones as described in some of the gain setting threads.
]i can wrote:
set the amp at 4 volts, but when i turn it to the next lower 2.5 volts it pounds way harder
That's called "turning up" the gain. You are positioning the amplifier to respond to a different signal than if it were at the different voltage input. If the gain's position ends up at or near that point after you've successfully followed the steps in the proper gain setting procedure, then that is where it should be and should remain.
]but a wrote:
i wrong thinking that this is damaging my subs
No, you are not wrong to be mindful of creating a situation that could damage your equipment. The real danger, though, is in not knowing how to properly set the gain.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.