PA Systems & Speakers

Hi, new to this - just had my pacemaker fitted 3 weeks ago today - problem is I've been told to avoid heavy duty speakers.
Now I'm a musician & I use a compact PA system which comprises 2 x Peavy PR10 speakers (200w each peak 400 each) 1 x KME 12 in stereo bass bin - (2x 12in bass speakers in 1 cab max 600 watts ) & a 750 watt pa amp. which gives me all I nees for the venues I am doing as a one man band.

Now does anybody who is in the know have any idea am I safe to use this gear, is there a 'safe' distance to be from the speakers ie. 2 or 3 feet away - there must be some other musician out there who has faced the same problem - I'm 56 & just got my mojo back & I'd like to use it !! -Thanks

5 Comments

Do you have a harmonica ...

by donr - 2012-06-06 06:06:15

...in your one man band?

Dunno if there are any other hard rock musicians herebouts, but lemme give you my take on magnets. There is a member named Electric Frank who knows more about magnets than old Gauss, himself. (which doesn't take much because he was a mathematician, not a Fizzicist. They just named the field strength thingy after him.)

We are all different when it comes to sensitivity for magnets. Also, you did not say WHY you have the PM. Sometimes that can make a big difference.

My first guess is that unless you back up every speaker you own so that they nearly touch you w/ the back (where the humongous magnets are) you are safe. The magnet's strength does no vary w/ ear shattering volume you use, so that is not a variable for you.

Here's what you do: Since you are Irish, get a pint of Guiness. Set up your rig in stages, just like if you were going to perform. No wires, no other gear - JUST the speakers. Set up the one w/ the biggest magnets first. If you don't know which one it is, just guess! Start walking around within the area centered on the speakers. See if your PM & heart tell you anything. (Have you had an interrogation yet? What you are looking for is the feeling that you get when they hold the hockey puck like magnet over your PM to test it.) You'll feel it when the magnets affect your PM. If they affect you, move away from them. Add speakers one or two at a time & repeat the process. Do this till you have walked around inside the volume (Physical, not aural) defined by your speakers.

After you pass this test, which I'm sure you will, hook up the Amp & put in your ear plugs (You DO wear them while performing, don't you?) & crank that sucker up sloooooooowly to see if it affects you. It should not unless you pick it up & hold its output transformers right next to your chest. You'll probably get burned from the heat output before you feel any magnetic effect. BTW: You probably burn 750 watts as waste energy from the amp if its output is 750 watts. (Is your amp a relic from the stone age with BIG matched tubes for the output stage? I have a Harmon Kardon 120 watt amp that is so bleeding heavy I can't pick it up by myself. Lotsa steel in the output transformers.)

As a piece of trivia - the field strength of a magnet falls off as the square of your distance from it. How close to your speakers do you have to be for the magnets to give you any sensible force on a light piece of iron or steel? Bet you don't know, because there isn't that much attraction outside the speaker boxes - & it's probably 6 inches from the outside the box to the magnet. So - if you are 3 feet from the box, the field strength is !/36 of the strength it is at the box - which we have already guessed isn't very much.

I think you are safe anywhere, but the only way to know is to run this little experiment. Besides, what else are you going to do while recovering your ability to twang the guitar? (And it's a good excuse for a pint!)

Don

distance

by Tracey_E - 2012-06-06 07:06:22

As don said, 6" is about as close as you'd probably have to get to cause problems so it should be fine. Get near them and see how you feel. Even if it does have an effect, and odds are it won't, it doesn't do any damage. The thing that they put over it to test it is a magnet. The magnet pulls a switch closed and puts it in the test mode so it'll have limited function and you may feel strange. As soon as you move away from it, it opens back up and is fully functional again.

Much appreciated

by bazzac - 2012-06-07 05:06:19

Thanks guys - I was hoping that it should be ok, just that the the surgeon nearly took a turn when I told him I used speakers capable of taking 1000 watts rms.
The set up I use has a bass bin (sub woofer) which is placed on the floor always at least 6-7 feet away from me & the mid & high range are about head hight again 6-7 feet away minimum. All the equipment is fairly new - the top speakers (mid & high -brand new)
Not due PM test 'til 17th July & am still at the stage of not being allowed to raise my left arm over my head but feeling great & NOW looking forward to gigging again with renewed energy - reason for PM was slow/irregular heartbeat ( around 32bpm) - so much appreciated & best of luck
Barry

A different outlook

by ElectricFrank - 2012-06-07 10:06:09

It doesn't seem like much, but I never take the approach that I'm not allowed to raise my arm over my head. I say I have chosen not to raise it. When the doc writes in his records that I refuse to take statins for my chloresteral I tell him to write that I have chosen not to take them.

Using this language continually reminds that he recommends and I listen and then chose. I am in charge. It feels so much better.

frank

From Old Gaus Frank Himself

by ElectricFrank - 2012-06-07 12:06:54

Actually at my age 82 I'm pretty de-gaused.

The others said it. The most likely affect would be from the magnets in the speakers, and only then if they are real close. The thing to keep in mind is to avoid carrying the speaker real close to your body.

Don't pull my stunt. I bought a used Jeep with a custom audio system. I had no use for carrying it around when I was driving ledge roads so narrow that a good bass boom would likely put me over the side into a canyon and ruin my whole day. Anyhow it had a monster woofer behind the rear seat. So I took it out and without thinking carried it against my chest into the shop. No problem, but later when I was answering a question like yours I realized what I had done. By the way I'm 100% paced so would have noticed if anything had happened.

There's no problem with radiated electrical fields from you speakers. Depending on what your condition is and how your pacer is adjusted you could have an option called Rate Response which senses the movement of your body. It is used to determine the optimum heart rate to pace at. It isn't always needed though. The doc can tell you if it is turned on. The issue with RR is that it could sense the vibration of your body from heavy bass. This is sound pickup, not electrical. All that will happen is that your HR may increase without there being a need for it. You can either move away from the bass speaker a bit, or you can tell yourself that your music is intense you are just getting emotional.

Have at it and enjoy. My approach is that I would rather be found dead with a smile on my face than sitting in a rocker with a scowl.

frank

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