Re: [MLUG - DISCUSSION] Teen Repellent

["Vern Green" <EMAIL:PROTECTED>]

Actually a correction is in order here.

You can create lower tones with a smaller driver with a properly tuned
cabinet. I read an article where guys were taking the smallest drivers
they could find and porting them into the floors of their homes in
order to produce sub-hearing frequencies.

While you do not need a very large driver to create low frequencies
you do need a properly ported enclosure.

I built some sound enclosures with dual 15 inch speakers in them where
I ported the cabinet to reproduce down to 30hz. The wave-form rolls
off very quickly below 30hz. The idea again is to really shake the
foundations more than actually hearing anything that low, but using
the smaller speakers made the bass you did hear sound tighter.

This is the idea behind using 10 inch speakers on bass guitar
cabinets. The sound of the ten inch speakers is very tight even when I
play a low B note.


On 6/7/06, Mark Rages <EMAIL:PROTECTED> wrote:
> On 6/7/06, Mike Miller <EMAIL:PROTECTED> wrote:
> > On Wed, 7 Jun 2006, Jerry Gamblin wrote:
> >
> > > You could try it on this webpage I think:
> > >
> > > http://www.phys.unsw.edu.au/~jw/hearing.html
> >
> > That is a pretty cool web page, but there is a major difficulty with using
> > it to measure your hearing, even informally, because your speakers might
> > cut off at the low and high ends so that they don't even make the sound
> > you are trying to hear.
> >
> > I can't hear anything at 60 Hz on my system, nor at 16 KHz.  This doesn't
> > make sense to me though because the low A on my guitar is at 110 Hz, so
> > the low A on a bass is at 55 Hz and I can hear that just fine.  I'm sure
> > the overtones help me to hear it, but still.  There's also the famous "60
> > cycle hum" that I can hear just fine.
> >
> > That is a very cool page though.
> >
> > Mike
> >
>
> You need a physically large driver to make sound at 60 Hz.  Nowdays,
> it's more common to put a rise in the bass response at about 150Hz,
> and cut off entirely around 80Hz, and let the ear/brain fill in the
> lower two octaves.  This is what all the dinky "satellite / sub"
> combos do. I think Bose was first to popularize this acoustic hack.
> But when you hear a system that accurately makes the lower bass, you
> feel it as much as hear it.
>
> All this to say, I'm sure your computer speakers aren't producing much
> output at 60Hz.
>
> Re: 60 cycle hum.  In electronics, the sine wave is frequently
> rectified into a 120Hz wave with a lot of overtones.  A pure 60Hz size
> wave has a deep, pure sound like an organ pedal.  The powerline buzz
> that you hear when you touch your dinger to a live guitar cord is
> almost entirely overtones.
>
> Regards,
> Mark
> EMAIL:PROTECTED
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--
Thanks
F Vernon Green

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