EQ'ing around the crossover frequency

EQ guys are using on their cabs/systems. A good starting place if you don't have your own RTA.
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Chris_Allen
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EQ'ing around the crossover frequency

#1 Post by Chris_Allen »

This has always got me scratching my head.

My T39's get more sensitive around 100Hz and I want them fairly flat. So, rather than boosting the lower end, I EQ down at the top end. The problem comes with the DR's. They aren't very strong at 100Hz but I pull EQ before the crossover so it makes my 100Hz on the DR200s very, very weak - compromising the crossover point. I can move the crossover point up but then I am mid band on the EQ.
  • Do I get another EQ for the subs and pull down afterward the crossover
  • EQ up below 80Hz?
  • Leave the EQ at 100Hz and move the crossover frequency lower on the subs and decrease the slope to LR12?
  • Just live with it?
Built:
6xDR200, 2xT39, 2xT48, 2xJack110, 1xOmni10.5, 1xAutotuba, 1xT18, 1xSLA Pro, 1xW8, 1xW10

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Radian
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Re: EQ'ing around the crossover frequency

#2 Post by Radian »

Chris_Allen wrote:Do I get another EQ for the subs and pull down afterward the crossover
I wouldn't. Use the LPF as your primary means of shaping the subs' response. You have to the use the filter anyway, so knock two birds out with one stone to preserve response to the maximum extent.
Chris_Allen wrote:EQ up below 80Hz?
Only if the room or source material dictates.
Chris_Allen wrote:Leave the EQ at 100Hz and move the crossover frequency lower on the subs and decrease the slope to LR12?
That's a good start, but "Where is your crossover frequency?" :confused: That's the real question.

The crossover region and the low-pass / high-pass filter settings do not share the same frequencies.

Just because a filter is set at 100Hz or 80Hz does not mean the system crosses-over there. RTA the subs, then RTA the tops to find out where each really signs off in application. It can't be stressed enough that phase has to be checked in the acoustic cross-over region, not where the filters are set.
Chris_Allen wrote:Just live with it?
:cop: Not an option. It's your gear, you built it, you get to drive it. :mrgreen:
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CoronaOperator
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Re: EQ'ing around the crossover frequency

#3 Post by CoronaOperator »

What are you using for a crossover? The Behringer DCX2496 lets you set shelving parametric eq's for each channel. One parametric eq on the subs would flatten out the subs response and would be a better tool than cutting 6 separate graphic eq's.

Like Radian said, check your phase at the crossover frequency to make sure the tops and subs are not working against each other.

Lastly, if your weak at 100hz then boost 100hz (within reason) or overlap the crossover region or lower your crossover slopes. Nobody said you have to crossover the subs and tops at the same frequency. What difference does it make if the 100hz comes from the tops or the subs or both? Experiment to see what sounds the best.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
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For best results, point the loud end of the array towards the audience

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Bill Fitzmaurice
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Re: EQ'ing around the crossover frequency

#4 Post by Bill Fitzmaurice »

Better crossovers allow for independent setting of the low pass and high pass. The way to compensate for the high sensitivity of the T39 at the upper end of its pass band is to lower the LP frequency, say to 80 or 90Hz, depending on how steep the slope. The idea is to arrive at a relatively flat summed response in the crossover region before applying any EQ.

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Chris_Allen
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Re: EQ'ing around the crossover frequency

#5 Post by Chris_Allen »

I am using the DCX and DEQ.

I cross at around 107Hz for subs and tops as I feel this is where my DR200's are happiest. I have checked phase before but not recently and both tops and subs have been taken apart and reassembled since then.

I'm perfectly happy with the sound overall but feel there is something missing around the crossover point. There isn't a null point, so I'm fairly happy that everything is in phase but I should really check anyway.

I completely forgot about the parametric EQ, good idea.
Built:
6xDR200, 2xT39, 2xT48, 2xJack110, 1xOmni10.5, 1xAutotuba, 1xT18, 1xSLA Pro, 1xW8, 1xW10

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Israel
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Re: EQ'ing around the crossover frequency

#6 Post by Israel »

im on number 3 with a little twist set the subs lpf to 80 maybe less and the slope to 12db8 but also raising the hp filter on the subs and the slope if you can will help on boosting the low end without the risk of overexcursion
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CoronaOperator
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Re: EQ'ing around the crossover frequency

#7 Post by CoronaOperator »

Chris_Allen wrote:I am using the DCX and DEQ.
I have checked phase before but not recently and both tops and subs have been taken apart and reassembled since then.
That is something I would check at every venue as the placement (distance) between subs and tops can change. Play a 100hz - 120hz tone and using the dcx2496 you can easily swap phase 180' on the subs at the push of a button and listen by ear for the louder tone.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

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