Am I Preparing My Speakers for their funeral?

djblyden · **Joined:** Sat Apr 14, 2012 6:50 am **Posts:** 18

I have 4 Eminence Delta Pro 12 A Drivers with the Nominal Impedance* 8 ohms
Power Rating**
Watts 400W
Music Program 800W

I'm currently running 2 Drivers off of 1 channel from my CS 3000. The problem is that when i start to crank up the alternators to 1/2 way the speakers get really loud and start pushing hot air. Is it that i'm providing the speakers with more that they can handle? this was done indoors. i have a gig coming up and would like to play all four off of the CS 3000. (2 per channel). Should this be done? All advice would be appreciated.

In addition i have 4 Eminence Omega Pro 18 A Drivers with Nominal Impedance* 8 ohms
Power Rating**
Watts 800W
Music Program 1600W
and would like to know which CS amp to buy to power all 4 Omega Pro 18 A from one single amp (2 drivers per channel)??/

SemperFiSound · **Posted:** Sun Apr 15, 2012 12:23 pm

djblyden wrote:

I have 4 Eminence Delta Pro 12 A Drivers with the Nominal Impedance* 8 ohms
Power Rating**
Watts 400W
Music Program 800W

Is this in a guitar cabinet? And since your moniker is djxxxx, I am going to assume not, what cabinets are these in? Are there horns?

IF the speakers are wired in parallel, that would be a 4 Ohm load and the CS-3000 will push ~1000 Watts per channel into a 4 Ohm load, so each speaker can get 500W - that should be fine.

djblyden wrote:

The problem is that when i start to crank up the alternators to 1/2 way the speakers get really loud and start pushing hot air.

I am also going to assume that you mean "attenuators" and not alternators - unless that is some new DJ box I am unfamiliar with.

Here's a better way to start:
Read this paper on Gain structure:
Gain Structure:
viewtopic.php?f=28&t=20293&p=153715&hilit=gain+structure+paper#p153715

Paper too complex? Here's an abbreviated version, but I have no way of knowing what else is on your system, so take proper caution.
- Turn down EVERY mixer & slider and Gain knob and attenuator you have to the least position.
- Turn the CS-3000 gain knobs (attenuators) to Max.
- Do you have a crossover or an EQ between the mixer and amp? If so, adjust those to 0 dB (usually 12 o'clock.
- Anything else between the mixer and the amp? Set it to 0 dBu.
- Set you music source (iPod, computer, whatever) to halfway.
- Raise your Master slider slowly until the volume is correct for the venue. Not enough volume? Get a bigger rig.

djblyden wrote:

In addition i have 4 Eminence Omega Pro 18 A Drivers with Nominal Impedance* 8 ohms
Power Rating**
Watts 800W
Music Program 1600W
and would like to know which CS amp to buy to power all 4 Omega Pro 18 A from one single amp (2 drivers per channel)??/

Again, it depends on the cabinet they are in, are there other drivers? For just two per channel, wired in parallel, a CS-4080 at 2040 per side into a 4 Ohm load isa good pairing. An IPR-7500 would also be a good pairing.

These are as good a recommendations that can be made with the info you have provided.
A complete system listing will aid any further recommendations.

Cheers,
Steve

djblyden · **Joined:** Sat Apr 14, 2012 6:50 am **Posts:** 18

Thanks SemperFiSound. i'll upload a pic later to show the cabinets that they are in. The Omega Pros are in cabinets designed like scoops and the Delta are placed 2 in 1 cabinet. Does wiring in parallel mean that one signal comes from the amp to one speaker and then from the one speaker to the other? The speaker wire is set so that one Speakon output from the amp send two signals to the speakers.

SemperFiSound · **Posted:** Mon Apr 16, 2012 8:46 am

djblyden wrote:

Does wiring in parallel mean that one signal comes from the amp to one speaker and then from the one speaker to the other? The speaker wire is set so that one Speakon output from the amp send two signals to the speakers.

Parallel wiring means that the + from the amp is attached to the + of the speakers and the - from the amp is attached to the - of the speakers.
Serial wiring means that the + from the amp goes to the + of the first speaker, then the - from the first speaker goes to the + of the second speaker and then the - from the second speaker goes to the - on the amp.

One speakon connector (or any connector, for that matter) can feed the cabinet BOTH ways - depending upon how the cabinet is wired internally.

The wiring affects the impedance and reliability.
If wired in series, the impedances are merely added. Two 8 ohm speakers combine for a 16 Ohm load. If one speaker goes south, the other speaker will not play either.
If wired in parallel, the impedances are inverse additive, (1 / ( 1/x + 1/y)) so two 8 Ohm speakers would be (1 / (1/8+1/8)) => (1/ (2/8)) => (1/ (1/4)) = 4. Obviously, if you have different impedance drivers this gets more involved. If one of the speakers goes pffft, the other one will still play.

Hope this helps,
Steve

djblyden · **Joined:** Sat Apr 14, 2012 6:50 am **Posts:** 18

k. thanks.
this is what the cabinets look like. i inherited the cabinets and would like to add more later on. is the Eminence drivers good?

djblyden · **Joined:** Sat Apr 14, 2012 6:50 am **Posts:** 18

Would a G Sub cabinet with two 18 inch drivers sound better than 2 scoops with 18 18 inch drivers?

SemperFiSound · **Posted:** Mon Apr 16, 2012 2:21 pm

Okay, got it. What crossover are you using and what do you have it set for?
And like I asked for above....we need a complete lisitng of everything in the signal path.

Cheers,
Steve

djblyden · **Joined:** Sat Apr 14, 2012 6:50 am **Posts:** 18

Don't have a cross over as yet. Intend on getting the pv35xo later in the month. I'm going out of a laptop to a old Sony 8 Channel Audio Mixer (MXP -290) out of the mixer to the CS 3000.

SemperFiSound · **Posted:** Mon Apr 16, 2012 2:56 pm

Is the CS-3000 driving ALL those cabinets?

djblyden · **Joined:** Sat Apr 14, 2012 6:50 am **Posts:** 18

it was only driving 1 of the mids (2 delta pro 12A) and the Lows (1 Omega Pro 18 A) as in the pic. I have a next one of the mids and would like to drive the two from the CS 3000 alone. I'll buy the CS 4080 to power the four Lows that i have.

djblyden · **Joined:** Sat Apr 14, 2012 6:50 am **Posts:** 18

I meant to ask Would a G Sub cabinet with two 18 inch drivers sound better than 2 scoops with 18 inch drivers? sry about 18 being repeated.

Marty McCann · **Joined:** Mon Oct 27, 2008 3:50 pm **Posts:** 3491

YOU NEED AN ELECTRONIC X-OVER!

djblyden · **Joined:** Sat Apr 14, 2012 6:50 am **Posts:** 18

thanks for the advice Marty. I'm getting the pv35xo later in the month. i live in Guyana, South America and to get gear u have to ship it from the US or pay double the price of it locally. (if it's available).
I would like to know if i should change from the scoop design to the G sub design? Would 2 LF drivers in 1 cabinet deliver more punch that2 LF drivers in two scoop cabinets?

I inherited the stuff that i currently have and plan to invest as time goes bye into equipment to provide small sound reinforcement.

Am I Preparing My Speakers for their funeral?

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