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JBL VRX Series Speakers

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Danny Baies:
Here's the scenario i stumbled upon...

Few years back i moved to another state and to another church. I got involved with the audio department.
Ever since i was there i noticed that the sound is not right in the church. They remodeled this church and totally overhauled the sound system.

We have JBL VRX932LA and JBL VRX918S. These speakers are mounted in ceiling in array . In front we have 4 VRX932LA and 1 JBL VRX918S. All this speakers are interlinked, so the output from a speaker goes into the input on the next speaker.

The info i got from the ones that installed them is that they connected 2 speakers per pair.

From what i figured out is that these speakers are connected in parallel and they get output from a Crown CE2000. The problem is that is not enough power that comes out of those speakers. They are not loud enough.

The specs on the Crown CE2000 are that they can take load of 2,4,8 Ohms. Since the 2 (8 ohms) speakers are connected in parallel that get a 4 ohms input.

What can be wrong? Anyone any ideas ?

Thank you.

Ivan Beaver:
Danny Baies wrote on Tue, 28 December 2010 16:07
Here's the scenario i stumbled upon...

Few years back i moved to another state and to another church. I got involved with the audio department.
Ever since i was there i noticed that the sound is not right in the church. They remodeled this church and totally overhauled the sound system.

We have JBL VRX932LA and JBL VRX918S. These speakers are mounted in ceiling in array . In front we have 4 VRX932LA and 1 JBL VRX918S. All this speakers are interlinked, so the output from a speaker goes into the input on the next speaker.

The info i got from the ones that installed them is that they connected 2 speakers per pair.

From what i figured out is that these speakers are connected in parallel and they get output from a Crown CE2000. The problem is that is not enough power that comes out of those speakers. They are not loud enough.

The specs on the Crown CE2000 are that they can take load of 2,4,8 Ohms. Since the 2 (8 ohms) speakers are connected in parallel that get a 4 ohms input.

What can be wrong? Anyone any ideas ?

Thank you.

It could be anything, based on your limited description of the problem.  Stating that the sound is "not right" does not tell us anything at all.

Possibilities; Damaged loudspeakers- wrong aiming-not setup properly-wrong design for the room-FOH mixing skills-wiring error and on and on.

More details would help A LOT

Danny Baies:
well, the speakers are not damaged, aiming maybe, room size not proper for sound but it seems not loud as it should be and anything that gets close to 0db amplified it turns into feedback.

The speakers are rated for 800W, at 8ohms. The amp outputs 400W at 8ohms but because we have 2 speakers in parallel at 4ohms the amp outputs 660W and there is no feel at all of 600w from the speakers. My surround system at home is more powerful that the speakers at church. I will make a diagram to explain more on this subject.

Thank you.

Arnold B. Krueger:
Danny Baies wrote on Wed, 29 December 2010 01:59
well, the speakers are not damaged, aiming maybe, room size not proper for sound but it seems not loud as it should be and anything that gets close to 0db amplified it turns into feedback.



If you are saying that the loudness of your system is limited by feedback (howling), then amplifier power is most certainly not the problem.

Before I go on, is your system limited by howling feedback?

Dick Rees:
Danny Baies wrote on Tue, 28 December 2010 20:59
well, the speakers are not damaged, aiming maybe, room size not proper for sound but it seems not loud as it should be and anything that gets close to 0db amplified it turns into feedback.


What does that mean?  The statement "0dB amplified" is meaningless.  What are you trying to say?

Quote:

The speakers are rated for 800W, at 8ohms. The amp outputs 400W at 8ohms but because we have 2 speakers in parallel at 4ohms the amp outputs 660W and there is no feel at all of 600w from the speakers.


Yes, if there is only one power amp the speakers would be underpowered.  That does not mean that they won't get "loud", though.  From the first part of your post it would seem that the output of the system is limited by the onset of feedback, not by the speakers and amp(s).

Quote:

My surround system at home is more powerful that the speakers at church.



Your system at home does not have open microphones, so you can turn it up as much as you like.  The system at the church has open microphones and the feedback loop from them is what is limiting the output of the system, not the equipment itself.

It is obvious from your attempts at delineating the problem that you have little experience with live sound and a preconceived notion of what's "wrong" with things. That's two strikes right there.

Just exactly what is your role in your church?  Are you officially in charge of anything, part of a team/committee or just a critical listener?  Have you been tasked with assisting with the "problems" or are you just posting here for sympathy and corroboration of your opinions?


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