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  1. #1

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    Red face New head unit!! Help please

    Well, it is finally installed:

    CD7100 :D

    But now I have some questions, as my older head unit had NO kinds of adjutments.

    I know tuning is personal, and I have to be listening to what sounds best, but I really have no idea as to how to start, for there are quite a few settings to play with, and I had nothing before. It feels like I'm being thrown into the ocean.

    But to be more specific...

    Should I let the head unit do the crossovers? Basically, should I just open up the amps to do their work?? Will the head unit actually send just the signals needed to the amps?

    Which do I tune first? The amps (gains, filters, crossovers), or the head unit (crossovers, equalizer, time alignment)??

    When it comes to the crossover... so far I have it as:

    Subs start cutting out at 125 hz with a sharp slope (24 db/oct) as I do not want it trying to make any high notes. I have 2 Infinity Kappa Perfect 10.1's

    Speakers are at 250 hz with a smallers slope (6db/oct). They are some alpine SPX177r's.

    Rear speakers I have no clue, I have the fader mostly to the front anyway, they are my oldest part of the system Polk db6500's.

    And I suppose I shouldn't mess with the speaker's crossovers right?

    Sorry if all this sounds dumb, but with so many things to adjust I would like to find a starting point. I tried looking online for some sort of guide but to no avail, if anyone knows of something it will be really helpful.

    As it is though, the CD7100 is VERY VERY nice... the sound is significantly better than my old head unit, and it looks very nice. I just need an Ipod now as their USB support majorly sucks.

  2. #2

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    First thing I do is unplug the RCAs and see what volume the radio goes up to. Say it goes up to 40, I'll tune it to where the maximum the speakers will handle will be at volume 30. This helps to ensure your radio wont send a clipped signal when youve got it really cranked.

    Next, plug the RCAs in and gains all the way down with volume at 30. (Dont plug anything into the amp, RCAs or otherwise with the radio on.) One amp at a time, turn it up until you hear audible distortion, then back it back down a notch. Same with the other amp.

    This gives you a starting point for the gain. Not the best way, but if you dont have access to a multimeter and o-scope, its pretty damn good.

    As far as crossovers go, dont put the subs at anything higher than 80. If your components dont handle a lot of bass, do 80 with a shallow slope, like 3 or 6. If they are capable of it, then id do a steeper slope, like 12 or 24.

    Components that dont handle a lot of bass, 125Hz with a 12 db slope, comps. that do handle it, 100 with a 24 db slope.

    If you ever want to really jam, it wouldnt be a bad idea to turn your comps slope back up to 250 so you dont blow em.

    As far as the rear speakers go, get a girlfriend and give them to her.
    -Cody
    Music is like candy, you have to get rid of the rappers to enjoy it

  3. #3

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    Thank you!

    I did adjust the gains in the amp first... The head unit goes to 80 so I did it at 60, which is 3/4's (same as you said). It needs to get really loud before any distortion though, so I left them both around 1v (goes from .2 to 2), even though the head unit is supposedly 8v out. Then I had to lower the gain on the sub a bit as it was a little too much for my taste.

    Anyway, that's not really my main problem. What I would like to know more is if I should trust the head unit with the crossover settings, and leave the amps with the filters off. Or should I set the crossovers in both the head unit and the amps? That's what I"mnot sure about, or whether I should set one first then the other? Or does it even matter? Haha, sorry.

    Anyway, the settings of the crossovers did help a lot. I had the speakers set for only highs. It's just hard to imagine that the speakers range is from ~125 all the way upwards 20000 hz, whereas the subs only manage from about 20-200 max?? The range for the speakers is a lot more and yet the subs require a lot more power. I'm sure it makes sense with physics, but I just didn't get it.

    Thanks again. I did read about the time delay in the manual, so I will set it the way the manual suggests and then I'll fine tune with some mono male voice from an AM station as another thread suggested.

    Demon :)

  4. #4

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    Use the crossovers in the head unit. Theyll be fine and its a lot easier to fine tune sitting in the drivers seat than having to get out and go back to the amps everytime you want to try a different setting.
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D

  5. #5

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    I use the crossovers on the head unit and the amp, just set the ones on the amp a little higher so its the headunit doing all the work. Reason being if someone ever messes with your radio and screws over your crossover settings, you dont have components and subs playing full range.
    -Cody
    Music is like candy, you have to get rid of the rappers to enjoy it

  6. #6

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    That is true, but having crossovers overlap each other can cause all kinds of phasing issues not to mention just screwing up the sound.

    Crossover settings are usually buried fairly deep in most HU menus, so its doubtful anybody could accidentally turn them off. And if you ever have anybody sit in your car and just start messing with buttons, you should slap them and instruct them in proper car audio etiquette.
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D

  7. #7

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    Quote Originally Posted by MacLeod View Post
    And if you ever have anybody sit in your car and just start messing with buttons, you should slap them and instruct them in proper car audio etiquette.
    haha, i couldn't agree more.

  8. #8

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    One thing about setting the amp gain on subwoofers. Make sure you fade out your components so that you only hear your sub. That way you can hear the distortion better when you set the amp gain. Setting that amp gain correct on subs is the life of the sub. Because when your playing your music loud. It's hard to hear a sub distorting when you have the highs blarring.

  9. #9
    stereo_luver
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    Quote Originally Posted by cam5860 View Post
    One thing about setting the amp gain on subwoofers. Make sure you fade out your components so that you only hear your sub. That way you can hear the distortion better when you set the amp gain. Setting that amp gain correct on subs is the life of the sub. Because when your playing your music loud. It's hard to hear a sub distorting when you have the highs blarring.
    Maybe set the amp gains properly in lieu of listening for distortion?

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