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Bronze Member Username: JronPost Number: 33 Registered: Jul-05 | i just installed an mrd-m605 amplifier in my car with a 1242 type r alpine 9847 is the head unit i am running. The question i need answered is how to adjust the input sensitivity. I have had several opinions but due to your car audio experience i would like your input. the sensitivities run from 0.2-8v on the setting of the amplifier.all this is in a sealed box, I also wanted to know what you think is the best setting to run it at 50-80hz. i think the pre-amp output is rated at 2v max. any input would be greatly appreciated man. thanks. |
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Gold Member Username: GlasswolfWisteria, Lane USA Post Number: 8882 Registered: Dec-03 | about one quarter turn, closest to the .2 position. half way is 4 volts. so you want about one-quarter of the way for 2 volts. try about 60Hz for starters |
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Bronze Member Username: JronPost Number: 35 Registered: Jul-05 | thanks for the info man. the setting on this amp is a digital one. i either have a choice of 1.5 or 2.5, i think i am going to go with the 1.5v. and take it from there, I think the hu would clip first anyways. Let me know if you think my decision is wrong. once again thanks for the advice. |
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Bronze Member Username: Cnc837Norman, OK USA Post Number: 20 Registered: Jul-05 | I just ordered that same amp. What do you have your other settings at? Is your input sensitivity set based on how many volts your hu puts out? |
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Bronze Member Username: JronPost Number: 37 Registered: Jul-05 | man it is the weirdest thing. when i turn the gain up to 1.5v or 2v i get all this distortion, at a low volume, say around 12. the hu supposedly puts out 2v max, but it sounds like crap at 2v distorted, but the distortion goes away if I drop it down to .1v-.3v kind of like it reversed or something. and another thing this amp only really kicks if i turn the bass unit setting on the head up, havent screwed around with the bbe function on the amp, i wonder if that could possibly be the problem. I hear that if everything is adjusted correctly you can turn the bass up if needed through the deck, and the subwoofer adjustment is turned up pretty high too. gain adjustment takes place with the defeat on. but even with tweaking and everything at 1.5 to 2.5v there is no 2 setting on the digital readout it sounds like crap. i am in okc too man graduated from OU go sooners! |
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Bronze Member Username: Cnc837Norman, OK USA Post Number: 22 Registered: Jul-05 | Have you tried calling the Alpine Help Number? Its 1-800-421-2284. What year did you graduate from OU? I will be a senior this year, but still have 2 years left. |
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Bronze Member Username: JronPost Number: 39 Registered: Jul-05 | 2002 man, thanks for the number. |
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Bronze Member Username: JronPost Number: 41 Registered: Jul-05 | just called them man not much help. i may just go ahead and turn the gain to 1.5 and use the bbe on the amp and take it from there. in theory i do believe that you want to be as close to the output of the hu as possible though. i think that i even read somewhere that once your settings in the hu go past 0 that even adds another volt so instead of turning the gain to 2v, you could turn it to 1v, because the head unit would clip before the amp. anyways man whatever you do let me know how it turns out. |
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Bronze Member Username: Cnc837Norman, OK USA Post Number: 23 Registered: Jul-05 | Try this website: http://www.bcae1.com/gaincon2.htm I found it in another thread. Glasswolf is the one who posted this. It sounds like you're right about matching the head unit to the amp voltage. The one thing I noticed though, that the lower the voltage you set it at, the higer the gain is. You'll see what I mean in that link, hope it helps. |
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Bronze Member Username: JronPost Number: 42 Registered: Jul-05 | thanks man i am going to set it at 1.5 because i cant find a 2v setting on it. i am also going to use the bass boost function on the amp and see how it sounds. |
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Bronze Member Username: JronPost Number: 43 Registered: Jul-05 | yeah man i have been asking around and for some reason that amp sounds best at .1 v. I talked to a guy at best buy, one of their installers, with the same set-up as me, and he told me he runs his at .1v too. He said it's weird, but that he guesses thats just the way alpine made that particular amp. I have mine at .1v and 60hz, and it hits pretty hard man. I am going to turn it up to 80 hz next and see how it sounds. I adjust everything through the head unit, and once you get your hands on the bass equalizer that's when the subwoofer really shines. Once again I tried the gain at 1.5 and there is basically no way i could compensate for the distortion, maybe hitting the bbe function on the amp is the only way. drop it to .1v-.2v and it sounds awesome with no bbe. Let me know what you did man, as the guy at best buy didnt explain things well to me about the gain reasoning. peace. |
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Bronze Member Username: Cnc837Norman, OK USA Post Number: 24 Registered: Jul-05 | I'm still waiting for mine to come in the mail. It should be here saturday. Do you know if there is any risk at running it with the gain turned up that high? Do you still have the Bass Boost on the amp at 0? |
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Bronze Member Username: JronPost Number: 47 Registered: Jul-05 | man i have no clue. usually when people run the gain too "high" it is turned all the way up clockwise, really all the way down, i think that is when you run into the most trouble. i am running it on the lowest setting, so i do not know. yeah the bass boost is at 0, i adjust it through the head unit. |