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HU's - AMP's and Xovers , noob needs Xover advice
HU's - AMP's and Xovers , noob needs Xover advice
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Old 21st January 2009, 01:26 AM   #1
metaverse is offline metaverse  United States
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Question HU's - AMP's and Xovers , noob needs Xover advice

Hey All ,

I've been messing around with my new deck and mixed Factory system with a 15" in the trunk in IB setup and trying to understand the Xovers better and was wondering if you could offer some insight for a beginner.

Here's some info:

The Bose system [stock amps - 1 for each speaker wired directly into the deck preamps]:

- Front = 2x tweets and 2x 6"s in the doors by the kickpanels

- Back = 2x 6"inches just below the rear windshield above the back seats.

- Added to that I have an earthquake 700w bridged mono to a Dayton 15" IB subwoofer attached to a plywood and mdf baffle in the trunk.

- Clarion DXZ785USB deck [5.8 volt preamps]

::: :::

On the amp i've got it set to level 2 out of 7 on the gain.
The treble is all the way down and the bass is turned to 6 out of 7.

Do the treble and bass dials act as High pass filters and Low pass filters ??

... ...

With the deck I have the options of both a HPF and a LPF for my "highs/mids/sub" ... what are some good settings to begin with ??

I tend to listen to alot of aggressive bass music with dreamy atmospherics and vocals but generally also listen to most genre's of music.

But overall i'm just trying to get the most SQ out of my system ...

anything helps
~ eric
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Old 21st January 2009, 02:47 AM   #2
ppia600 is offline ppia600  United States
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The bass and treble aren't crossover dials, just for bass boost and treble boost. I would turn the treble all of the way down and then play with the bass level after setting the crossover on your deck to about 80hz.
Don't worry... you can always turn the gain down!
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Old 21st January 2009, 01:30 PM   #3
metaverse is offline metaverse  United States
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Join Date: Sep 2008
Location: Massachusetts
Hey ppia ,

Thats kind of what I thought but I figured i'd rather make an *** out of myself and ask the question than mess something up

Also ...

I actually just had someone tell me that a good basic rule of thumb for my ranges is to set:

HPF for my tweeters at around 4khz or higher

HPF for my mids at 150hz and the LPF at 4khz

LPF for my sub would be at 150hz ...


I also heard that I should just put my sub LPF at 80hz ??

And just to clarify I can set both a HPF and a LPF for each of the 3 sections [highs, mids and sub] making 6 possible filters.

I'm guessing either I wasn't clear on this OR you guys aren't commenting on anything because its more of a system specific thing ??

If thats the case would you say the above ranges are a good Basic starting point or something different ??
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Old 21st January 2009, 04:23 PM   #4
ppia600 is offline ppia600  United States
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I usually try around 80hz at first because of the differences in crossover slopes some decks or amp crossovers have. If its a steep sloped crossover you may need to move it up to a higher frequency. If the crossover has a low db per octave slope you may need to use a lower frequency. In the end you don't want to "hear" anything coming from the rear of the vehicle. The goal is to focus the sound in front of you usually, and while its difficult to make good midbass sometimes, you can do a lot of tweaking and get close. Depending on your mids capabilities I would use a lower hp than 150hz, otherwise you may hear the music coming from the trunk instead of around you in the cabin.

The frequency selection you're describing would work well on a home theater setup with seperates directly in front of you, but will draw your attention to the trunk when there is a lot of midbass information in the music if in a vehicle.
Don't worry... you can always turn the gain down!
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Old 21st January 2009, 06:01 PM   #5
jol50 is offline jol50  United States
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I always end up running lower LP with IB, say 35-50Hz, and changing the slope if I can to tune. It depends on the sub some will make a lot of ~100Hz IB (efficient ones) and some will cut themselves back. I often run mids down to 80 give or take, and would run them lower when I can with a higher slope.

IB often works better with lower LP and not as sharp a slope, then the subs will play reduced above the LP....or you have to EQ them that way. Many of them will become powerful midbass otherwise and you don't get any ~30Hz. Also tends to blend better into mids that way. I also like strong bottom <35Hz that gives me. You might need a subsonic if they move too much, and will for sure if you want to power them up hard IB. Most subs only take about half RMS rating when IB, so keep your eyes on xmax if you beat on it.
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Old 22nd January 2009, 06:15 AM   #6
tsmith1315 is offline tsmith1315  United States
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I agree with ppia600 and jol50, and yes it is a bit of a system specific thing.

Your factory speakers will last longer with the highest HP crossover point that sounds good.

Your woofer will be less muddy and obtrusive with the lowest LP crossover point that sounds good.

Your musical tastes will also be a large factor. Ideally, the subwoofer would blend naturally with the rest of the system. Some folks like the sub to dominate the rest of the system.

The main thing is to do adjustments systematically. Some general tips that work for me:

-Start with ALL tone and gain controls flat. That includes bass, treble, EQ, etc in the head unit, bass and treble on the Earthquake, gain control on the amp at minimum, and sub gain on the head unit at 0.

-After each adjustment, listen a bit to hear the results of what you've done.

-Adjust the LP crossover frequency for the sub down to ~40Hz and adjust the HP to around 100Hz for the stock speakers. This will leave a bit of a gap, but that will allow you to hear what the stock speakers are doing. Crank it up pretty loud and move the HP down as far as you can without straining the stock speakers.
I wouldn't go below ~70 Hz HP. If you can adjust front and rear independently, you may find they like different HP points.

-Next work the sub LP frequency up until it blends well.

-Next, work the Earthquake's gain control up until the level is where it sounds best to you.

-Now take a while to listen to different types of music and at different volumes to make sure what you've done so far is working well.

It may be hard, but try to avoid fiddling with the Clarion's EQ and tone controls during this process. The Bose speakers are already equalized pretty well for the car, and boosting the bass on the head unit will affect the HP characteristics for these speakers. Let the subwoofer and its amp do the hard work down low.

Next, work the Earthquake's bass EQ up little by little and repeat the last listening session.

Your personal taste will dominate the end result, so only rules of thumb apply. Chances are you can find a happy place in what you've done so far, and leave the head unit's tone, EQ and Sub levels pretty much flat. Hopefully, they can be reserved for minor adjustments while driving.

And BTW, you may find yourself tweaking these adjustments for a long time to come.

Still got that warm place to work?
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