Speaker installation

Don't put the holes through the hull below waterline.

Just a thought

jofra
 >> Stay informed about: Speaker installation 

"Jofra" <jofra RemoveThis @es.co.nz> wrote in message
news:cvdf53$mvt$1@lust.ihug.co.nz...
 > Don't put the holes through the hull below waterline.
 >
 > Just a thought
 >
 > jofra
 >

I hope he doesn't put hole through the hull anywhere on the boat for this
speaker installation. <!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

Might be a good idea to determine what's behind the bulkhead before
drilling and cutting. If you cut the hole accurately, you can use SS
wood screws in correctly sized holes to attach them.
JR
Jay wrote:

 > So I finally found a set of speakers that seemed like a good enough deal and
 > they came in last week. I'm wondering if anyone has any input/experience
 > installing speakers. They aren't flush mount which needs I'll need to be
 > cutting a few holes... some of my curiosity lies in wondering if there's any
 > certain saw blades one should use for cutting fiberglass.... I was going to
 > just drill a few holes to start a hand jig saw... maybe tape up the area
 > with duck tape to avoid scratching.. other than that I didn't really know if
 > there was anything one should take precaution with.
 >
 > Also, though they weigh a couple pounds each, should I worry much about
 > providing some of support to the backing... like a brace to dissipate weight
 > on the fiberglass walls?
 >
 > TIA
 >
 > -j
 >
 >


--
--------------------------------------------------------------
Home Page: <a style='text-decoration: underline;' href="http://www.seanet.com/~jasonrnorth" target="_blank">http://www.seanet.com/~jasonrnorth</a><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

Basic physics: take note of the distance sound leaving the rear surface of
the speaker has to travel through the air to reach the front of the speaker.
Any sound with a wavelength longer that this distance will cancel itself out
as the sound from the front is perfectly out of phase with the sound from
the rear. No bass in other words. An enclosure effectively creates an
infinite distance from front to rear as the two out of phase sound waves
can't get to each other. they are blocked form meeting by the walls of the
enclosure. If the enclosure is too small the speaker ends up using up most
of its power trying to compress the air inside the enclosure resulting in
little low bass as well. So the enclosure has to be both well sealed and
big enough to be effective. It is possible to vent an enclosure with a
tuned port (often called bass reflex) allowing a smaller enclosure but that
isn't simple physics any more...
--
Ken Heaton
Cape Breton Island, Canada
kenheaton AT ess wye dee DOT eastlink DOT ca


"Jay" <nono.TakeThisOut@noneforyou.com> wrote in message
news:18pSd.15405$zA7.124@fe06.lga...
 > The birch idea sounds good..
 > Can't say I gave enclosures much though.. sounds like I need to though. ..
..
 >
 > -j
 >
 >
 > "Doug Kanter" <ancientangler.TakeThisOut@hotmail.com> wrote in message
 > news:yfeSd.9798$Fl4.2848@news02.roc.ny...
  > > "Jay" <nono.TakeThisOut@noneforyou.com> wrote in message
  > > news:eqaSd.5953$cx3.1503@fe04.lga...
   > >> Sorry, that was a bit uninformative..
   > >> They weigh about 2 or 3 pounds/piece. They didn't come with back
braces,
   > >> and they would probably mount ok... my concern is the shock of slamming
   > >> over wakes over time, cracking the perimeter...
  > >
  > > Get yourself a piece of 3/4" birch ply. Cut a square for each speaker,
  > > about 2" bigger than the speaker. Cut your holes in the fiberglass. Make
  > > them perfect. Put the birch ply behind the holes you've made, trace the
  > > holes onto the plywood, and cut holes in that, too. Actually, do that
  > > ***BEFORE*** you've cut it into squares. The big piece of ply will be
  > > easier to clamp to a work surface than the smaller squares. Mount the
  > > speakers with the wooden squares as bracing from behind.
  > >
  > > One thing you didn't mention: What will be the enclosure BEHIND the
  > > speakers? For any speaker, there's a very small range of correct
enclosure
  > > size. Get far from that range and the speaker becomes all but useless in
  > > terms of bass response. Trying to get decent bass by dicking around with
  > > tone controls will just overdrive your radio or amplifier, and blow up
  > > your speakers in short order. Hint: In even the quietest cars, you need
  > > about 75 ***CLEAN*** watts per channel to overcome road noise. If you
  > > intend to run this stereo in a boat while the engine's running, you need
  > > about twice that much power. Otherwise, you'd better be a big fan of
  > > distortion and blown speakers.
  > >
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

Ken Heaton wrote:
 > Basic physics: take note of the distance sound leaving the rear surface of
 > the speaker has to travel through the air to reach the front of the speaker.
 > Any sound with a wavelength longer that this distance will cancel itself out
 > as the sound from the front is perfectly out of phase with the sound from
 > the rear. No bass in other words. An enclosure effectively creates an
 > infinite distance from front to rear as the two out of phase sound waves
 > can't get to each other. they are blocked form meeting by the walls of the
 > enclosure. If the enclosure is too small the speaker ends up using up most
 > of its power trying to compress the air inside the enclosure resulting in
 > little low bass as well. So the enclosure has to be both well sealed and
 > big enough to be effective. It is possible to vent an enclosure with a
 > tuned port (often called bass reflex) allowing a smaller enclosure but that
 > isn't simple physics any more...

Good explanation. It also helps to know the wavelengths. Sound travels
about 1127 ft/second in air and wavelength = velocity/frequency so...

freq. wavelength
(Hz) (ft)

20 56
40 28
80 14<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

"-rick-" <nobody RemoveThis @home.com> wrote in message
news:6rGdnZJFp5ngOYffRVn-1g@comcast.com...
 > Ken Heaton wrote:
  >> Basic physics: take note of the distance sound leaving the rear surface
  >> of
  >> the speaker has to travel through the air to reach the front of the
  >> speaker.
  >> Any sound with a wavelength longer that this distance will cancel itself
  >> out
  >> as the sound from the front is perfectly out of phase with the sound from
  >> the rear. No bass in other words. An enclosure effectively creates an
  >> infinite distance from front to rear as the two out of phase sound waves
  >> can't get to each other. they are blocked form meeting by the walls of
  >> the
  >> enclosure. If the enclosure is too small the speaker ends up using up
  >> most
  >> of its power trying to compress the air inside the enclosure resulting in
  >> little low bass as well. So the enclosure has to be both well sealed and
  >> big enough to be effective. It is possible to vent an enclosure with a
  >> tuned port (often called bass reflex) allowing a smaller enclosure but
  >> that
  >> isn't simple physics any more...
 >
 > Good explanation. It also helps to know the wavelengths. Sound travels
 > about 1127 ft/second in air and wavelength = velocity/frequency so...
 >
 > freq. wavelength
 > (Hz) (ft)
 >
 > 20 56
 > 40 28
 > 80 14
 >

All good points. If he can't build a perfect enclosure, a good ballpark
figure (at least with my experience) is that most car doors are a "pretty
good size" for decent 5" to 6" speakers, assuming they've got at least 10-15
watts of CLEAN power driving them.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

"-rick-" <nobody.DeleteThis@home.com> wrote in message
news:6rGdnZJFp5ngOYffRVn-1g@comcast.com...
 > Ken Heaton wrote:
  >> Basic physics: take note of the distance sound leaving the rear surface
  >> of
  >> the speaker has to travel through the air to reach the front of the
  >> speaker.
  >> Any sound with a wavelength longer that this distance will cancel itself
  >> out
  >> as the sound from the front is perfectly out of phase with the sound from
  >> the rear. No bass in other words. An enclosure effectively creates an
  >> infinite distance from front to rear as the two out of phase sound waves
  >> can't get to each other. they are blocked form meeting by the walls of
  >> the
  >> enclosure. If the enclosure is too small the speaker ends up using up
  >> most
  >> of its power trying to compress the air inside the enclosure resulting in
  >> little low bass as well. So the enclosure has to be both well sealed and
  >> big enough to be effective. It is possible to vent an enclosure with a
  >> tuned port (often called bass reflex) allowing a smaller enclosure but
  >> that
  >> isn't simple physics any more...
 >
 > Good explanation. It also helps to know the wavelengths. Sound travels
 > about 1127 ft/second in air and wavelength = velocity/frequency so...
 >
 > freq. wavelength
 > (Hz) (ft)
 >
 > 20 56
 > 40 28
 > 80 14
 >

Holy cow. This ain't rocket science folks.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

"JimH" <Me DeleteThis @aol.com> wrote in message
news:cJidnaKWvI7YuYbfRVn-tg@comcast.com...
 >
 > "-rick-" <nobody DeleteThis @home.com> wrote in message
 > news:6rGdnZJFp5ngOYffRVn-1g@comcast.com...
  >> Ken Heaton wrote:
   >>> Basic physics: take note of the distance sound leaving the rear surface
   >>> of
   >>> the speaker has to travel through the air to reach the front of the
   >>> speaker.
   >>> Any sound with a wavelength longer that this distance will cancel itself
   >>> out
   >>> as the sound from the front is perfectly out of phase with the sound
   >>> from
   >>> the rear. No bass in other words. An enclosure effectively creates an
   >>> infinite distance from front to rear as the two out of phase sound waves
   >>> can't get to each other. they are blocked form meeting by the walls of
   >>> the
   >>> enclosure. If the enclosure is too small the speaker ends up using up
   >>> most
   >>> of its power trying to compress the air inside the enclosure resulting
   >>> in
   >>> little low bass as well. So the enclosure has to be both well sealed
   >>> and
   >>> big enough to be effective. It is possible to vent an enclosure with a
   >>> tuned port (often called bass reflex) allowing a smaller enclosure but
   >>> that
   >>> isn't simple physics any more...
  >>
  >> Good explanation. It also helps to know the wavelengths. Sound travels
  >> about 1127 ft/second in air and wavelength = velocity/frequency so...
  >>
  >> freq. wavelength
  >> (Hz) (ft)
  >>
  >> 20 56
  >> 40 28
  >> 80 14
  >>
 >
 > Holy cow. This ain't rocket science folks.
 >

Actually, it's *is* science, although it's not always possible to apply it
accurately in cars & boats. You just do the best you can, using the rocket
science as a guideline. And even if you're building freestanding speaker
cabinets for home or stage use, the science assumes a perfect speaker cone
which doesn't add color of its own, which is pretty much fiction. Even so,
the science works.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

On Tue, 22 Feb 2005 12:55:24 GMT, "Doug Kanter"
<ancientangler.RemoveThis@hotmail.com> wrote:

 >
 >"JimH" <Me.RemoveThis@aol.com> wrote in message
 >news:cJidnaKWvI7YuYbfRVn-tg@comcast.com...
  >>
  >> "-rick-" <nobody.RemoveThis@home.com> wrote in message
  >> news:6rGdnZJFp5ngOYffRVn-1g@comcast.com...
   >>> Ken Heaton wrote:
   >>>> Basic physics: take note of the distance sound leaving the rear surface
   >>>> of
   >>>> the speaker has to travel through the air to reach the front of the
   >>>> speaker.
   >>>> Any sound with a wavelength longer that this distance will cancel itself
   >>>> out
   >>>> as the sound from the front is perfectly out of phase with the sound
   >>>> from
   >>>> the rear. No bass in other words. An enclosure effectively creates an
   >>>> infinite distance from front to rear as the two out of phase sound waves
   >>>> can't get to each other. they are blocked form meeting by the walls of
   >>>> the
   >>>> enclosure. If the enclosure is too small the speaker ends up using up
   >>>> most
   >>>> of its power trying to compress the air inside the enclosure resulting
   >>>> in
   >>>> little low bass as well. So the enclosure has to be both well sealed
   >>>> and
   >>>> big enough to be effective. It is possible to vent an enclosure with a
   >>>> tuned port (often called bass reflex) allowing a smaller enclosure but
   >>>> that
   >>>> isn't simple physics any more...
   >>>
   >>> Good explanation. It also helps to know the wavelengths. Sound travels
   >>> about 1127 ft/second in air and wavelength = velocity/frequency so...
   >>>
   >>> freq. wavelength
   >>> (Hz) (ft)
   >>>
   >>> 20 56
   >>> 40 28
   >>> 80 14
   >>>
  >>
  >> Holy cow. This ain't rocket science folks.
  >>
 >
 >Actually, it's *is* science, although it's not always possible to apply it
 >accurately in cars & boats. You just do the best you can, using the rocket
 >science as a guideline. And even if you're building freestanding speaker
 >cabinets for home or stage use, the science assumes a perfect speaker cone
 >which doesn't add color of its own, which is pretty much fiction. Even so,
 >the science works.

Ahem - cough, cough... :>)

The science is only a guide. Sound, and fidelity which is a concept
that seems to have escaped into the ether these days, is entirely
subjective. Being subjective, what may sound good to you will not
sound good to me.

Having perfect pitch and sensitive hearing, it's one reason I don't
attend movie theaters unless I'm dragged kicking and screaming.

Later,

Tom<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

"Short Wave Sportfishing" <emaildisguised.DeleteThis@askme.com> wrote in message
news:4ebm11thp5spts980jail5shmru39r776j@4ax.com...
 > On Tue, 22 Feb 2005 12:55:24 GMT, "Doug Kanter"
 > <ancientangler.DeleteThis@hotmail.com> wrote:
 >
  >>
  >>"JimH" <Me.DeleteThis@aol.com> wrote in message
  >>news:cJidnaKWvI7YuYbfRVn-tg@comcast.com...
   >>>
   >>> "-rick-" <nobody.DeleteThis@home.com> wrote in message
   >>> news:6rGdnZJFp5ngOYffRVn-1g@comcast.com...
   >>>> Ken Heaton wrote:
   >>>>> Basic physics: take note of the distance sound leaving the rear
   >>>>> surface
   >>>>> of
   >>>>> the speaker has to travel through the air to reach the front of the
   >>>>> speaker.
   >>>>> Any sound with a wavelength longer that this distance will cancel
   >>>>> itself
   >>>>> out
   >>>>> as the sound from the front is perfectly out of phase with the sound
   >>>>> from
   >>>>> the rear. No bass in other words. An enclosure effectively creates
   >>>>> an
   >>>>> infinite distance from front to rear as the two out of phase sound
   >>>>> waves
   >>>>> can't get to each other. they are blocked form meeting by the walls
   >>>>> of
   >>>>> the
   >>>>> enclosure. If the enclosure is too small the speaker ends up using up
   >>>>> most
   >>>>> of its power trying to compress the air inside the enclosure resulting
   >>>>> in
   >>>>> little low bass as well. So the enclosure has to be both well sealed
   >>>>> and
   >>>>> big enough to be effective. It is possible to vent an enclosure with
   >>>>> a
   >>>>> tuned port (often called bass reflex) allowing a smaller enclosure but
   >>>>> that
   >>>>> isn't simple physics any more...
   >>>>
   >>>> Good explanation. It also helps to know the wavelengths. Sound
   >>>> travels
   >>>> about 1127 ft/second in air and wavelength = velocity/frequency so...
   >>>>
   >>>> freq. wavelength
   >>>> (Hz) (ft)
   >>>>
   >>>> 20 56
   >>>> 40 28
   >>>> 80 14
   >>>>
   >>>
   >>> Holy cow. This ain't rocket science folks.
   >>>
  >>
  >>Actually, it's *is* science, although it's not always possible to apply it
  >>accurately in cars & boats. You just do the best you can, using the rocket
  >>science as a guideline. And even if you're building freestanding speaker
  >>cabinets for home or stage use, the science assumes a perfect speaker cone
  >>which doesn't add color of its own, which is pretty much fiction. Even so,
  >>the science works.
 >
 > Ahem - cough, cough... :>)
 >
 > The science is only a guide. Sound, and fidelity which is a concept
 > that seems to have escaped into the ether these days, is entirely
 > subjective. Being subjective, what may sound good to you will not
 > sound good to me.
 >
 > Having perfect pitch and sensitive hearing, it's one reason I don't
 > attend movie theaters unless I'm dragged kicking and screaming.
 >
 > Later,
 >
 > Tom

Add to that the fact that the guy is installing a $30 pair of speakers in an
open cockpit of a boat.

Nope, it ain't rocket science.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

"Short Wave Sportfishing" <emaildisguised.RemoveThis@askme.com> wrote in message
news:4ebm11thp5spts980jail5shmru39r776j@4ax.com...
 > On Tue, 22 Feb 2005 12:55:24 GMT, "Doug Kanter"
 > <ancientangler.RemoveThis@hotmail.com> wrote:
 >
  >>
  >>"JimH" <Me.RemoveThis@aol.com> wrote in message
  >>news:cJidnaKWvI7YuYbfRVn-tg@comcast.com...
   >>>
   >>> "-rick-" <nobody.RemoveThis@home.com> wrote in message
   >>> news:6rGdnZJFp5ngOYffRVn-1g@comcast.com...
   >>>> Ken Heaton wrote:
   >>>>> Basic physics: take note of the distance sound leaving the rear
   >>>>> surface
   >>>>> of
   >>>>> the speaker has to travel through the air to reach the front of the
   >>>>> speaker.
   >>>>> Any sound with a wavelength longer that this distance will cancel
   >>>>> itself
   >>>>> out
   >>>>> as the sound from the front is perfectly out of phase with the sound
   >>>>> from
   >>>>> the rear. No bass in other words. An enclosure effectively creates
   >>>>> an
   >>>>> infinite distance from front to rear as the two out of phase sound
   >>>>> waves
   >>>>> can't get to each other. they are blocked form meeting by the walls
   >>>>> of
   >>>>> the
   >>>>> enclosure. If the enclosure is too small the speaker ends up using up
   >>>>> most
   >>>>> of its power trying to compress the air inside the enclosure resulting
   >>>>> in
   >>>>> little low bass as well. So the enclosure has to be both well sealed
   >>>>> and
   >>>>> big enough to be effective. It is possible to vent an enclosure with
   >>>>> a
   >>>>> tuned port (often called bass reflex) allowing a smaller enclosure but
   >>>>> that
   >>>>> isn't simple physics any more...
   >>>>
   >>>> Good explanation. It also helps to know the wavelengths. Sound
   >>>> travels
   >>>> about 1127 ft/second in air and wavelength = velocity/frequency so...
   >>>>
   >>>> freq. wavelength
   >>>> (Hz) (ft)
   >>>>
   >>>> 20 56
   >>>> 40 28
   >>>> 80 14
   >>>>
   >>>
   >>> Holy cow. This ain't rocket science folks.
   >>>
  >>
  >>Actually, it's *is* science, although it's not always possible to apply it
  >>accurately in cars & boats. You just do the best you can, using the rocket
  >>science as a guideline. And even if you're building freestanding speaker
  >>cabinets for home or stage use, the science assumes a perfect speaker cone
  >>which doesn't add color of its own, which is pretty much fiction. Even so,
  >>the science works.
 >
 > Ahem - cough, cough... :>)
 >
 > The science is only a guide. Sound, and fidelity which is a concept
 > that seems to have escaped into the ether these days, is entirely
 > subjective. Being subjective, what may sound good to you will not
 > sound good to me.

I agree, for two major, recent reasons:

- As good as they are at testing some products, Consumer Reports refuses to
acknowledge that "testing" speakers is impossible. A friend of mine who
remained in the audio biz after I left says people still get excited about
Japanese speakers made of 1/4" plywood, because CR said they were a "best
buy".

- Any time you read about tests of cell phones, they're focused on network
coverage, and phone features that absolutely nobody needs, unless they
absolutely no other qualities which recommend them as a worthwhile person.
Never any mention of the audio-related design of the phones themselves. So,
we have cell phones with noise cancelling systems that play havoc with your
voice.

But, I disagree about one thing: You can come closer to theoretical
perfection with the bass frequencies than you can with higher frequencies.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

On Tue, 22 Feb 2005 14:05:41 GMT, "Doug Kanter"
<ancientangler.DeleteThis@hotmail.com> wrote:

~~ snippage ~~

 >But, I disagree about one thing: You can come closer to theoretical
 >perfection with the bass frequencies than you can with higher frequencies.

Ok, why?

Later,

Tom<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation 

"Short Wave Sportfishing" <emaildisguised.RemoveThis@askme.com> wrote in message
news:nafm11lssjaons4474ic2sjmqkcv456brr@4ax.com...
 > On Tue, 22 Feb 2005 14:05:41 GMT, "Doug Kanter"
 > <ancientangler.RemoveThis@hotmail.com> wrote:
 >
 > ~~ snippage ~~
 >
  >>But, I disagree about one thing: You can come closer to theoretical
  >>perfection with the bass frequencies than you can with higher frequencies.
 >
 > Ok, why?
 >
 > Later,
 >
 > Tom

I'll get back to you in a little while on this. My phones are ringing.
Damned customers don't understand that they're getting in the way of our
discussion here. <!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Speaker installation