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November 2005 Editorial

Kids and HiFi - Survival guide - Part II

Author: Lucio Cadeddu
Published: November, 2005

Here's the second part of our Survival Guide that should help audiophiles to save their systems from aggressive children. Summarizing, in the first part of the Guide, I concluded that leaving the kids FREE to experiment is the safest way to prevent serious problems with our HiFi systems. Anyway, uncontrolled freedom might lead to dangerous situations. I'll try to suggest some strategy to avoid the worst cases.

That volume knob...

Being the most visible knob in any amplifier or preamp, it is also the most attractive. Leaving that unprotected while the system is playing might be dangerous. Turning clockwise is one of the first learned movements of a child :-)
Once they learn that turning clockwise that knob increases the listening level, be sure they'll try to repeat that movement again and again ad libitum. Kids like high pressure sound levels. Don't ask me why. They can make some big noise by themselves, perhaps this is the reason why they like "loud" Music so much. If you've ever been into a kids classroom you may have an idea of the noise level they can bear without experiencing listening fatigue :-) Even a seasoned heavy metal band roadie might find it unbearable.
To scientifically prove my thoughts I asked my daughter to make the loudest cry she could. With a digital SPL meter, put at 1 meter of distance from the (lovely) source, I started measuring the intensity of her cries. Believe it or not, the SPL meter reached peaks of 115 dB (Weighted A) and stayed above 110 dB for most of the time (we made several attempts :-)).
Now you could just imagine what 115 dB of sound pressure mean when concentrated in a narrow area of the mid-high region of the audio spectrum. Unbearable is the closest description of the effect. Very few HiFi systems can produce such a sound pressure in that frequency range. Just to give you an idea, we're talking of something that is close to the sound of an airplane during take off. You may have a look at our Table of frequency and sound pressure related to musical instruments and normal life noises.
It is quite natural that little kids can make some extreme noise: they MUST be able to be heard by the parents in case of need (think at the early days of mankind...).

Perhaps for the same reason, they tend to prefer loud listening levels. This is not dangerous per se...but it may become so if you forget to have a look at the volume knob before turning on your HiFi system. It happened to me at least a couple of times to find the volume knob rotated fully clockwise!!! Kids can also be faster than you may imagine so, when they're around and close to the preamp or amplifier, be sure to keep the CD player remote handy, so to immediately stop the Music in case of extreme need. There exists a radical solution to the problem: a preamp (or amp) with a digital step by step volume control. Unfortunately these are not so widely popular as audiophiles tend to prefer the feeling of a real volume knob (me included).

Cables' nest

Banana connectors are very user-friendly and widely accepted by audiophile because they can be plugged/unplugged in a snap...you can imagine what this ease may produce when kids are around. A second of distraction and voilà, speakers cables can be unplugged from the speakers while the amp is on. Several problems may occour: first of all, many amps don't like having one or both channels without load; secondly, once unplugged, the positive and the negative poles can accidentally have a contact, creating a short circuit that may destroy the amp power stages.
In view of this potential problem, bare wire and/or forks are much safer as unplugging requires some extra work...and if you tighten the binding posts firmly it is almost impossible for a kid to unscrew them and unplug the cables.
For interconnects we have quite the same problem. Unplugging an interconnect while the amp is on may produce a shock to the amp and a loud THUMP on the speakers. The solution, in this case, is represented by locking RCAs (or XLRs) that can be tightened firmly on the female connectors, making the unplugging procedure a bit complicated.
As for mains cables, I admit the IEC inlets we love so much (because we can experiment different mains cables easily) are not the best choice in terms of safety and are potentially very dangerous, especially for kids. Be extremely careful with mains cables. Even if an "electric anti-hazard" device is fitted in your house...it is better to be safe than sorry.

Perhaps I've been lucky since, despite the number of HiFi components that crowd my house, I've never had problems with cables when my daughter was/is around.

The decay and fall of....loudspeakers

This is, by far, the darkest fear of any audiophile: the damage kids can do to a loudspeaker. For this reason many audiophiles hang the speakers high, so that kids can't reach them. BIG MISTAKE, and for two reasons: speakers should be placed so that the tweeter is in axis with listener's ears and secondly kids learn to use chairs quite early. Even when chairs are not enough, they can add piles of books till they can reach their target ;-)
The solution is not to put the speakers far away from children's reach, the solution is to make both coexist friendly!
The most kids-friendly loudspeakers are floorstanders: if heavy enough (or supplied with a large footprint) they are not easy to "rock". Kids tend to consider those as just another piece of furniture and hence their interest is, normally, low.
Bookshelf loudspeakers, installed on stands, might be dangerous and extremely attractive: they can fall, harm the kid and self-destroy during the process :-)
Also, many stands and speakers are installed on spikes and this might add extra danger. I'd avoid spikes whenever possible and use blue-tac instead. Four small blobs of the tacky substance and you're done! The whole structure (be it a tall floorstander or a flimsy stand) gets glued to the floor and it is almost impossible to make it fall. Actually, moving speakers once they've been blue-tac'ed isn't a straightforwrad task and may require a couple of minutes. The good news is that blue-tac isn't aggressive on wood finishes: it detaches without damaging the finish, with no stains, also.
So use it confidently. Furthermore, you may even discover that using blue-tac (or any similar device like plumbers putty) is beneficial to sound, sometimes producing better (sonic) results than spikes.

In order to save the speakers drivers from kids' fingers you can glue a metallic grid on the underside of the dust covers. If the grid is strong and "tight" enough it is virtually impossible to damage the drivers, even using pointed objects (yes, kids can be cruel).
When all else fails and you discover one of your precious tweeters has been pinched down by small lovely hands...don't panic! 99% of the times this isn't a real problem. You can try restoring the dome's shape with one of the following techniques:

I strongly suggest the first two procedures...while the third...well, be sure nobody's watching while you kiss the tweeters. For your neighbourhoods it might be the final proof of your insanity.
Anyway, as said, it is not easy to seriously damage a tweeter. Normally, if it sounds as before, no damage has occourred. If you aren't 100% convinced, contact the dealer or the manufacturer and ask for a replacement unit. You'll be surprised to learn how inexepensive tweeters can be ;-)

That's all, folks! Kids and HiFi could happily live together, without damaging each other.

© Copyright 2005 Lucio Cadeddu - www.tnt-audio.com

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