speaker noises

[highendtron]

I have a client that has two large speakers around his big screen TV 52" that thump when he cycles power on them. He ran twisted pair speaker wires along the back of the wall for the length of the room and has the speakers at both room corners. Both speakers are powered by wall receptacles along the same wall.
I had him run an extension cord from a different room (different circuit than the one in the TV room) and the speakers still made a noise when power was cycled. I thought that the speakers may have been picking up an induced field with the room conductors/circuit. I also told him that we might try running a pair of twisted wires in shielded cable. The floor above and below are finished ceilings so running wires perpendicular to the wall receptacles is not cost-effective . Any other ideas would be appreciated.

 

[mxslick]

What make and model are these speakers? What are they connected to, the TV or an a/v receiver?

If he is leaving the speakers powered up and is turning the a/v receiver off first/on last that can produce the thumps.

What kind of input connectors do the speakers have? If it's RCA, Phone (1/4") or XLR, then he should be using shielded wiire to connect them, NOT twisted pair. (Twisted pair of what, BTW is he currently using?)

More info would be helpful here..

 

[highendtron]

The speakers are "Definitive", model BP-206, hooked to an A/V "Denon model 8avr-3303. The speakers are hooked to the A/V using twisted pair non-shielded wires under compression terminals.

 

[hbiss]

How's powering up the speakers going to affect the wiring you have running to them?? It's the crummy speakers. Betcha even if you disconnect the inputs to them they still thump when power is applied. Well designed amps (and the amps in powered speakers) have circuitry to eliminate the turn-on thump. Many times it's as simple as a delayed relay that connects the speaker after the amp powers up.

-Hal

 

[MichaelGP3]

This statement is confusing to me....

This statement is confusing to me....

...... Both speakers are powered by wall receptacles along the same wall.......

Since I don't believe that these are 'powered' speakers.

 

[highendtron]

"Since I don't believe that these are 'powered' speakers"...
Well, maybe they are not "powered" speakers but they both have a 110 volt cord cap attached that plugs into 110 volt receptacles in the wall.

 

[LarryFine]

The speakers are "Definitive", model BP-206, . . .

As a Definitive Technology speaker system owner myself, I can tell you a few things:

The model is the BP-2006tl, not BP-206's.

Yes, they do contain powered sub-woofers.

The amplifiers do thump a bit at turn-on.


A quick test is to disconnect all of the wires, both speaker wires and the RCA cables if you're using one, and see if the same thing happens.

The odds are that it will, and your system wiring has nothing to do with it. It's a function of the design of the built-in amplifiers.

Side note: If you use RCA cables for the subs, do not also use the lowest speaker-terminal links, which feed the sub-amps also.

 

[electricalperson]

i have an SWR 500 watt bass amplifer going to a 4x10 cab and those speakers thump a bit when i turn the amp on. im guessing that its normal for that to happen

 

[fishin' electrician]

i have an SWR 500 watt bass amplifer going to a 4x10 cab and those speakers thump a bit when i turn the amp on. im guessing that its normal for that to happen

I hope that it thumps a ton after you turn it on