Slope

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Thread: Slope

Mr_Kebo

Silver Member

Username: Mr_kebo

Albertville, Al
USA

Post Number: 536
Registered: Nov-04

Posted on Wednesday, September 27, 2006 - 03:54 am:

i see people saying 12db slope and 24db slope. How do i set this? I have an eD NINe.2x amp for the focal 165K2P componets. How would i set the amp for the best performance?

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mixneffect

Gold Member

Username: Mixneffect

Orangevale, Ca.
USA

Post Number: 1093
Registered: Apr-05

Posted on Wednesday, September 27, 2006 - 11:36 pm:

Crossover slopes are the rate that the frequency will drop above or below the crossover point.

12 dB slope will drop 12 dB per octave.

From 20 Hz to 40 Hz is one octave. 40 to 80 Hz is another octave. 80 to 160 is another and so on... So basically upwards you double and downwards you cut in half.

Now,

At 12 dB, the crossover will start to reduce volume 12 dB per octave.

At 24 dB, the crossover will start to reduce volume 24 dB per octave.

Use the 12 dB slope if you want to get a gradual reduction, and still be able to hear some of the frequencies past the crossover point.

Or,

Use the 24 dB slope if you want a sharp reduction of frequencies past the crossover point.

Personally I would use the 24 dB slope because it protects the mid-bass driver from bottoming out at low frequencies. :-)

Mr_Kebo

Silver Member

Username: Mr_kebo

Albertville, Al
USA

Post Number: 549
Registered: Nov-04

Posted on Thursday, September 28, 2006 - 07:02 am:

how do i set this on my amps?

bob impact

Silver Member

Username: Bobimpact

Danbury, CT
US

Post Number: 169
Registered: May-06

Posted on Wednesday, October 04, 2006 - 11:53 pm:

It depends on the amp, many have a set slope, some allow you to select the slope with a switch. It appears that your amp (from a quick check online) only runs a 12dB per octave slope. I have had good success with the K2Ps running a variety of settings.
The 165 K2P's are unique in that their frequency response is 70Hz-22KHz. Comparing this range to a competitors you see that it is narrow (JL Audio's ZR650's run 48Hz-25KHz). Focal believes (In my opinion correctly) that a 6 1/2 shouldn't be playing lower than 70Hz.

Because of this, and the fact that your amp cannot run a 24 dB down crosover I would set your crossover around the 140Hz range. Your situation is certainly not ideal as you cannot set a more aggresive slope for these woofers. You would be well served to get an EQ that can run at least a 24 dB down slope.

Most good EQs can run at least 12 or 24, and many include settings for 6,12,24 and 30 db slopes.

PS: I apologize to the audio purists on this forum for the numerous subjects I gave lip service to, it was a pink noise day at the shop today and I'm shot.

Mr_Kebo

Silver Member

Username: Mr_kebo

Albertville, Al
USA

Post Number: 591
Registered: Nov-04

Posted on Thursday, October 05, 2006 - 09:02 am:

What good eqs do you recommend? A guy that works at tweeter i met is going to help me tune my system once im done building it. He recommended Audio Control but which model would you get? I will be running those focals off a JL 300/2 and 1 FI Q 12" off a JL 1000/1

bob impact

Silver Member

Username: Bobimpact

Danbury, CT
US

Post Number: 172
Registered: May-06

Posted on Thursday, October 05, 2006 - 11:32 am:

If you're running the 300/2 you will have a 12/24 selector on the amp. Run an EQ if you want to fine tune the sound from there, but if your only concern is the crossover point the JL will do it for you. Having a Tweeter guy helping out sound like a good idea to me. :-)