CD Horn Equalization

djock12

In reading the posted info on CD Equalization, is this something that the drive rack pa+ can do and if so would it be set automatically using the RTA Mic or is it something that must be configured by the user?

Gadget

It's only used when bi-a,ping or tri amping a speaker.. as in active speaker crossover...Are you running fullrange?
G

djock12

I am considering biamping my peavey sp2's.

Gadget

Ok, then follow this thread...
viewtopic.php?f=60&t=1080
as for the CD horn EQ...
http://www.peavey.com/support/technotes ... orn_eq.cfm

and essentially what the article says is...

Since the CD horns are now able to direct the high frequencies off axis, the amount of high frequency energy formally available directly on axis is less. Therefore the CD horn no longer measures flat directly on axis without its needed signal processing in the form of a special high frequency equalization that is designed to be the reciprocal or mirror image of the horn/driver high frequency roll off response. This is what is meant by constant directivity horn equalization (CD EQ). All CD horns roll off the higher frequencies at about -6 dB per octave, and the CD horn EQ is usually in the form of a +6 dB per octave boost beginning at about 3 or 4 kHz.

set a set a 6 db/octave hi shelf starting @ about 3-4khz...

More questions?
G

djock12

I may have more questions, but I need to study all of the info that you provided just to make sure that I understand. Thanks again for your help!

djock12

ok, I think I have most of my specs and configs on how I want to run my system. I understand the section on sp2 biamping and what preset to use. What would be the proper preset to choose if I am tri-amping with a mono sub?(The amp that I am using for the sp218 sub would be run in parallel mode with subs wired directly +1 -1 for the top sub and +2-2 for the bottom sub).

Gadget

What would be the proper preset to choose if I am tri-amping with a mono sub?

Why not set up a custom preset? Then you can configure the thing the way you want.. the Wizard will take you through the setup...

The amp that I am using for the sp218 sub would be run in parallel mode with subs wired directly +1 -1 for the top sub and +2-2 for the bottom sub).

That's a bad idea... NL4's are typically wired ...
1+1- lows
2+2- hi's
So,

Biamp the tops using the above,
and use 1+1- for the subs...build a jack panel if you have to that way you can't use the wrong wire for the wrong speaker...

For any further clarification we need much more info..
G

djock12

Gadget wrote:

That's a bad idea... NL4's are typically wired ...
1+1- lows
2+2- hi's

Biamp the tops using the above,
and use 1+1- for the subs...build a jack panel if you have to that way you can't use the wrong wire for the wrong speaker...

I am working on a jack panel now, I should have all of my cables and connectors by Friday. The 1+1- and 2+2- was how i was going to biamp the sp2 tops, but for the sp218 bottoms, they are dual 18 inch bass speakers. Here is a pic of the rear speaker panel of the sp218's.

Dennis

This panel offers you the option of running your dual 18 sub off of one amp channel at 4 Ohms OR running each individual 18 driver off of one amp channel at 8 Ohms. The second option will require more amp channels...do you need to run each 18 individually?

Dennis

djock12

I wanted to run each one individually. From doing additional research, it seems that the sound quality is better when each driver is run separate.

Gadget

I wanted to run each one individually. From doing additional research, it seems that the sound quality is better when each driver is run separate.

Well.. that all depends on the power available... you would NOT have the same output if you have a pair of 8 ohm woofers on a 3000 watt Behringer EPX amp (4 ohms 1500 watts per driver) and 8 ohm stereo (500 watts per speaker...) that's a pretty big improvement...

If you have the NL4 cables that are wired properly...(4 conductors...VERY expensive) there is no problem because they are wired properly...

G

djock12

thanks for the reply Gadget.

I am using 4 strand 10awg for my sub and it is powered by a peavey cs4080 (1250 watts per channle at 8ohms). I have the amp running in parallel with both speakers wired directly via the NL4 at the speaker end (all 4 wires). On the amp end 2 wires are the 1+1- and wired to one NL4 and going to channel B and the other 2 wires 2+2- going to the amp channel A.

Dennis

It looks to me like you can connect a 4 wire NL4 cable to channel A of the amp and pick up both the A and the B channels (A - 1+/-, B - 2+/-)

Dennis

djock12

Dennis wrote:

It looks to me like you can connect a 4 wire NL4 cable to channel A of the amp and pick up both the A and the B channels (A - 1+/-, B - 2+/-)

Would the amp see a 4ohm load or 8?

Dra

The "A" channel "#2" pins are permanently wired to the "B" channel outputs... so each channel operates as if (it actually is) connected separately. Just NEVER plug into a bi-ampable top cab.

DRA

Dennis

Dra wrote:

Just NEVER plug into a bi-ampable top cab.

Why? As long as the inputs are configured for the biampable cab, it should be fine. It looks to me like djock can set up the entire system(with biamped tops) with 4 amps and 4 NL4 cables.

Dennis

Dennis

I have just reread the thread and see there is only a single sub so all that is needed is 3 amps and 3 NL4 cables.

Dennis

Dra

Dennis wrote:

Dra wrote:

Just NEVER plug into a bi-ampable top cab.

Why? As long as the inputs are configured for the biampable cab, it should be fine. It looks to me like djock can set up the entire system(with biamped tops) with 4 amps and 4 NL4 cables.

Dennis

If connecting to the same amp with the same input (sub) signal.

DRA

Dennis

Now I understand your point and I will STFU

Dennis

Dra

A clarified misinterpretation is actually very useful. Though I should have been more clear to begin with.

DRA

djock12

thanks to all that have replied. It is all good info for me as I am still learning the drive rack as well as the pro sound nuances. Maybe one day when I grow up I can be a sound engineer

djock12

Ok, so I have all of my cables and have hooked them up to their respective amps. In the drive rack I did a custom 2x5 setup to start with and just doing some minor tweaks to see how things sound. The amp that I am using for the highs is receiving the proper signal and is driving the horns in the speaker, the same for the mid amp and the amp driving the subs.

When I try and do a separate configuration just for the bi-amped speakers without the sub, I cannot get the drive rack to utilize the mid amp for the mids of the bi-amped cabinet. What am I doing wrong? I don't want to use the amp that I am using for the lows to run the mids in the bi-amped cabinet. Is there a config that I can use that will recognize the bi-amped speaker configuration?

I have found that I can use the 2x5 and just turn off the third amp that runs the bass, but not sure if this is the correct thing to do. Please advise.

Dra

I would set up another 2x5 and configure the mid output (for lows)with the lower hi pass. That way you never have to deal with changing cables and risking oops's.

DRA

djock12

thanks for that Dra. Can you suggest a good crossover point and filter between the highs and the mids? I am struggling with that a little.

Dennis

djock12 wrote:

Can you suggest a good crossover point and filter between the highs and the mids? .

Peavey suggests 1800Hz xo point BW12 or LR12. Delay the high output 0.48ms.

djock12

I will give it a try.

thanks Dennis