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kirkprovine

Need help with cross over frequencys

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Hi. I Just bought a FiQ12 and am waiting for it to arive. But right now I have a Clarion cz702 hu with focal polyglass 165 vb front speakrs and focal polyglass 165 cvx back speakers and a alpine pdx-f4 amp running the speakers and one memphis mojo 12 and memphis amp in the back. Im replacing the mojo with the fi. When i turn the head unit all the way to max, the speakers clip. I have the amp turned all the way down and the amp in the headunit off. I have the system set to normal right now because i dont understand the 2 way and 3 way set ups options and what all the numbers mean. I dont know what all the corss over numbers are or what i should have running through my speakers and im kinda scared to mess with them so i dont mess them up. Am i putting to much power to the speakers? Or do i have something else wrong. I tried looking online, but i couldnt find anything really describing any of this. Its very frustrating. Please help.

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I'm not exactly sure I understand your question.  However, I will try to offer what assistance I can.

 

Just about any head unit will clip if you turn it all the way to the max.  Just don't do it.  You should set your gain on your amps properly.  You will need a test disc with pink noise on it, and a multi-meter.  There are many articles out there on how to do it.  I'm not going to get into it in this post, just do a search and you will find it.

 

As far as crossovers go, does your head unit have it built in?  It sounds like it from your description, but I just want to be certain.  If so, use your owners manual and follow the directions on how to get to it and how to set it.  As far as WHAT it should be set to, you should check the specs on your speakers.  Check out their frequency response.  I'm not saying that's where you should set it, but it's a good starting point. 

 

If you have any more specific questions, please just ask and I will do everything I can to assist.

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Turn everything off.

Disconnect the RCAs on the sub amp.

Turn the gain all the way down on both the speaker amp and sub amp.

Turn headunit on, set everything to zero or flat. Bass 0, treble 0, bass boost off, etc.

Play some music, and gradually turn the volume up on the head-unit until it distorts, then back it up until it sounds normal again. IE: volume 25/35 This is about your max volume for the HU.

Leave the volume at that max volume, IE: 25.

Turn the gain up on the speaker amplifier until it distorts, then back it up until it sounds normal.

 

Turn everything off.

Reconnect the RCAs on the sub amp.

Disconnect the RCAs on the speaker amp.

If your enclosure is sealed than you don't need to mess with the SSF (sub sonic filter) now. If your enclosure is ported than adjust the knob for the SSF until it's a few hertz below your enclosure's tuning.

Set the LPF (low pass filter) to 80hz.

Turn the headunit on, go to max volume, ie: 25

Play some music with bass you're familiar with / play test tones around 30,40,50hz, doesn't matter much.

Turn the gain up until it sounds distorted, and back it up til it's normal again.

 

Turn everything off.

Reconnect the RCAs on the speaker amp.

 

Now your speaker amp and sub amp have their gains adjusted to play to their max around that max volume, ie: 25.

 

You'll find that on some music you'll only be able to turn it up to 22, and on others you may go above 25 a bit. Just depends on the recording level of the music. You'll also notice that on some songs the bass may be a bit much, or too little, so you can use the bass level on the head unit to adjust a few clicks up or down.

 

Next thing I would do is confirm that the SSF is correctly set as sometimes the silk screen printed labels are off in relation to the gain adjustment.

To set the SSF to a specific frequency, turn the filter all the way down (10hz) and disconnect the sub.
Turn the volume on the HU up to some arbitrary level (the volume level itself doesn't matter), and play the 33hz test tone (if that is what you are trying to set your SSF to).
Measure the voltage output of the amplifier with a DMM. Then multiply this voltage by .707. So if you measure the voltage output and it's 2V, then you would multiply 2 * .707 = 1.414.
With the test tone still playing and your HU at the same volume level, turn the SSF knob up until the voltage drops to your calculated voltage, in my example that would be 1.414V.
This will set your SSF to 33hz.

 

If your enclosure is sealed than this isn't very important--I'd probably set it around 20hz. If your enclosure is ported, than I'd set a few hz below tuning.

 

Next I would play with the LPF setting, and see if it sounds better lower than or above 80hz. Personally with all the subwoofer drivers I've used I was always happy crossing over in the 50hz range.

 

 

------------------------

 

Your front speakers have passive inline crossovers already, so you probably won't need any of the filters on the speaker amp, so make sure the filters are either OFF, or the LPF is turned all the way up, and the HPF (high pass filter) is turned all the way down.

 

Next you can mess with the treble, mid settings on the headunit if you feel you need it.

 

There's a crash course on making a setup sound half way decent. smile.png

Edited by stefanhinote

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I have the same HU and it has a fantastic set of controls with it's crossovers, eq, DTA etc. but it can be a bit overwhelming if you're not familiar with what all that does or how to use it.

 

In the NORMAL mode it will run the crossovers in the most basic way they can be set.  It will only allow high pass filtering for the front and rear speakers and low pass for the sub at 60hz, 90hz, and 120hz.  MOST people run their components at around 90hz on the high pass filter, depending on the speakers and amp you may even be able to get by with 60hz.  It's no big deal to turn them on and play with which frequencies give you the best sounding response as in your case in that mode it won't do much and you don't have to worry about hurting anything with it.  When you turn on the filters it's going to reduce the amount of bass/midbass that plays through the Focal's, plain and simple.  The frequency you set it to determines what frequency in the bass/midbass it starts to filter.  Not much more to it than that, just keep in mind it's not a shelf or an instant reduction that NOTHING below that plays.  It has a roll off, like a hill, and if you think of the frequency setting being at the top of the hill, the frequencies below that setting are gradually reduced in strength as you go farther down the hill.

 

 

Hope that helps to make some sense of it.

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Kudos to Stephan and alton. fantastic advice to op. I have even learned a little. SSA equipment AND forum ftmfw!!

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hey thanks that helped a lot. Im not sure it was clipping or what not. the speakers were bottoming out i guess? any ways i set the headunit to pass through and let the amp do the filtering and it fixed the whole problem. then i set the gain and now the speakers play amazingly. im not sure what i was doing, but i guess i was trying to set the frequency range on the headunit and i had it set to 100 on the amp and maybe they were fighting each other? i have no idea. i just took the head unit out of the equation and let the amp do the work and now its awesome. and yes, the headunit is confusing as all hell. thx for the responses though.

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Sweet--Glad it sounds better. :)

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