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Stallion 05-23-2009 07:18 PM

New System New Problem
Dear AV Members HELP,

We just built a new santuary and installed a new sound system. I have a ZED428, QSC RMX2450 (1 for FOH Speakers, 1 for Monitors, 1 for subs), 3 FOH Speakers are EV SX300 in cluster, 6 Monitor Speakers are EV ZX1-90, 2 Subs Yamaha SW115, 5 Wireless Sennheiser EW135 G2, 4 Wired Sennheiser E835, CD/Cassette Player.

The Subs are Bridged and sounding great, The Monitors are split currently on amp channel 1 & 2 ( 3 on each) and sound great. My problem is with the FOH Speakers, I have have them Bridged on one Amp which is bringing my Ohm down real low. They were supposed to have run 3 lines to the amps for each speaker, but didn't and they have enclosed the sanctuary with firewalls, so I couldn't immediately pull new lines. We have only a temp occupancy until they put in correct fire doors. After we have permanent occupancy we will put in 2 more runs and separate each speaker.

Here's the real problem, only with the FOH Speaker, the others are great: The CD player will redline and distort if you get the volume where you need it. The same thing happens with the Wireless. I'M ASSUMING MY PROBLEM IS TO MUCH ON THIS ONE AMP, IF SO IS THERE ANYTHING I CAN DO UNTIL WE GET PERMANENT OCCUPANCY (APPROX 1 MONTH).


rbinck 05-24-2009 07:46 AM

Re: New System New Problem
You might try disconnecting one of the speakers to see if it is the problem for sure. If that works then some impedance matching transformers may work for you. I have used impedance matching volume controls for this type application just for the impedance matching with the controls set all the way up. Finding 300w units could be a problem.

The other possibility is the single amp may not deliver enough power to drive all three speakers. If that is the case you would need a larger amp. You do have the amp bridged? If not that would probably help a lot.

What is the wire size and length of the run?

Finally, there could be a lot of losses through the run if you are using low impedance output from your amp, 2 to 16 ohms say. Using a 70v line would probably correct that issue. If your amp has a 70v output, then get some 70v transformers for the speakers. If your amp does not have a 70v output then you would need a 8-16 ohm to 70v transformer for the amp end. I'm not sure it would be worth this option though because high power units are expensive.

stevign 11-22-2009 10:01 AM

Re: New System New Problem
I have a new sytem:
VTL tube amp
VTL pre-amp
Adcom CD/DVD Player
I'm still using my 2C Vandersteen speakers

I have my TV hooked up to the Pre-Amp and I get a buzz (not loud, I can only hear it when the sound is turned down) from both speakers. The high-end company who installed it has tried everything, even small in-line filter between the cable and the TV Cable box but nothing works.

So here's the question:

Although Power Conditioners are not "made" to correct ground problems I'm wondering if they ever do? The company that sold me this new stereo system suggests I buy the Furman - Elite 15PF - i - Power Conditioner anyway and it just "might" get rid of the buzz as well.

Any experience, opinions or comments?

rbinck 11-22-2009 10:50 AM

Re: New System New Problem
It really depends on the source of the buzz. If it is internal to the TV then the power conditioner probably won't. If it is a ground loop issue with your electrical system, possibly.

I assume from your equipment you are using analog outputs from your TV, if so:

To troubleshoot I would use a battery operated amp like a auto amp or headphone amp and see if the buzz was still present and if it is then the buzz is probably being induced internally in the TV. Use of an external ATSC tuner could then be an answer.

If you are using an optical or digital coax sound output:
The buzz would almost certainly be introduced by your TV. Again an external ATSC tuner may be the solution.

An ATSC tuner would probably be cheaper than the power conditioner as well.

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