Shielded speakers - what exactly does that mean for moving?

[slmcdonald7]

Hey all,

I first came to this site approximately two years ago as I began my search for a receiver and pair of floor standing speakers. After finding some direction in this site's reviews and forums, I ended up purchasing a Denon 3805 and a pair of shielded Paradigm Monitor 11 speakers. I have been happy with them ever since, and am looking forward to taking them with me when my wife and I move from the East coast to the West coast in a few short weeks. In planning how we will transport the speakers, however, two possible issues have arisen about the safety of moving in the same car with computer equipment:

1) Our vehicle is a Toyota Prius - which obviously uses more electrical and computational equipment than does our '97 Chevy S-10; and
2) We were planning on moving our laptops in the front seat of the car, and the speakers in the back.

My issues can be resolved if someone could answer the following question: what exactly does it mean that the speakers are shielded? Do the speakers emit a magnetic field when they are unpowered? Is it safe to store these speakers within a few feet of computer equipment? If it is safe(ish), how close can they get (e.g., is the distance between the front seat and the back seat too short - or is the distance between the back seat and the electrical/computational system of the car too short). They were shielded at the factory with Paradigm's Magneshield (tm) if that helps. These speakers have quite a few magnets in them (three bass drivers, one midrange driver, see them here). In short, I want to transport them in our car (rather than the back of our truck), so long as moving them doesn’t adversely effect our computers or our car.

Any insight into what effect the shielding of speakers has on their magnetic fields when they are unpowered would be greatly appreciated.

Thanks,
Stephen

 

[JennAir]

The purpose of shielding a speaker is to allow them to be placed next to CRT style televisions.
Shielding a speaker (actually the driver(s) are shielded) typically involves using a second magnet, known as a bucking magnet, on the back of the driver magnet. This keeps the magnetic field from creating a large stray field that can affect closly placed electronic equipment. How well it does this varies from speaker to speaker. There is still a stray field, however, it is typically small enough to allow CRT monitors or TVs to be placed reasonably close. With the air space inside the cabinet providing a buffer zone a CRT can often be placed immediately next to the speaker without adverse effect. This applies whether the speaker is powered or unpowered.
Based on your description I doubt you'll experience any trouble at all moving them in your car.

 

[ruadmaa]

Magnetic Fields

Hey all,

I first came to this site approximately two years ago as I began my search for a receiver and pair of floor standing speakers. After finding some direction in this site's reviews and forums, I ended up purchasing a Denon 3805 and a pair of shielded Paradigm Monitor 11 speakers. I have been happy with them ever since, and am looking forward to taking them with me when my wife and I move from the East coast to the West coast in a few short weeks. In planning how we will transport the speakers, however, two possible issues have arisen about the safety of moving in the same car with computer equipment:

1) Our vehicle is a Toyota Prius - which obviously uses more electrical and computational equipment than does our '97 Chevy S-10; and
2) We were planning on moving our laptops in the front seat of the car, and the speakers in the back.

My issues can be resolved if someone could answer the following question: what exactly does it mean that the speakers are shielded? Do the speakers emit a magnetic field when they are unpowered? Is it safe to store these speakers within a few feet of computer equipment? If it is safe(ish), how close can they get (e.g., is the distance between the front seat and the back seat too short - or is the distance between the back seat and the electrical/computational system of the car too short). They were shielded at the factory with Paradigm's Magneshield (tm) if that helps. These speakers have quite a few magnets in them (three bass drivers, one midrange driver, see them here). In short, I want to transport them in our car (rather than the back of our truck), so long as moving them doesn’t adversely effect our computers or our car.

Any insight into what effect the shielding of speakers has on their magnetic fields when they are unpowered would be greatly appreciated.

Thanks,
Stephen

Your speakers are shielded and are safe to place anywhere, they will not affect any other electronic gear. Even with unshielded speakers the magnetic field drops off rapidly after a few feet. You can test the magnetic shielding of any speaker with a simple compass. If you pass a compass past an unshielded speaker you will see the needle move to point toward the speaker. On a shielded speaker the compass needle remains pointing north.

 

[slmcdonald7]

I thank you both for your very solid explanations and advice, I will test their flux fields with both our CRT TV and a compass shortly.

Best,
Stephen

 

[warpdrive]

Your speakers are shielded and are safe to place anywhere, they will not affect any other electronic gear. Even with unshielded speakers the magnetic field drops off rapidly after a few feet. You can test the magnetic shielding of any speaker with a simple compass. If you pass a compass past an unshielded speaker you will see the needle move to point toward the speaker. On a shielded speaker the compass needle remains pointing north.

That's not a good test, even with a well shielded speaker, a compass will be affected somewhat a couple of feet away, because compasses are extremely sensitive devices (at least the good quality ones I own)

However, I definitely would not be worried about putting them near a computer system. I wouldn't set hold a bare hard drive close to the woofer, but there is little to no chance that your hard drive will be affected if you are just moving them together.