[mfreak]

I want to build a new enclosure, and do it right. So...

- Does it matter which face of the enclosure the drivers and ports are
on? On my current box, the ports are on the opposite face as the
drivers. An installer here says the drivers and ports should go on the
same face, which I'd rather do if there's no reason not to.

- For a 12w3v2-d2, JL 'recommends' a 1.75 cu ft box, with a 4" port
that's 15.25" long. I've been playing with WinISD, and I can get freq.
response as low as I want my making the box bigger and bigger. A JL
techy says I can make the box slightly larger to make up for some of
the driver displacement and port volume, but not to make it make it
larger than 1.85 or 1.9. They say they build and test boxes, and 1.75
IS optimal. The JL techy and the installer I talk to, neither of em
heard of WinISD, and neither trust any of 'those goofy box programs on
the internet'. The installer said he'd build it 1.75 GROSS volume.

..75" MDF is fine, right? I was planning on 1", but home depot and
Menards only sell .75. I assume that's ok, since that's what my
existing box is. Anything better to use?

TIA,

[The Lull]

First, 3/4-inch MDF is great material.

Now - the bigger the box, the lower fequency response you can get,
THEORETICALLY. It doesn't always turn out so well. I once made a box
that had one Jensen 10-inch sub in just over 3 cubic feet (ported, of
coarse, and tuned to 26 Hz using WinISD). The specs on the sub said it
could handle 175 watts rms, and I had it hooked up to a JBL amp that
said it put out 150 watts rms. What happened? I blew that sub within
a month. It would seem that I had pushed the sub beyond it's specified
limits, and/or the sub was slightly overrated, and/or the amp was
slightly underrated. Personally, I believe it was a combination of the
three reasons.

However, I currently have a box that drive 1 10-inch JBL woofer with a
volume (after taking out port and driver volume) of nearly 2.5 cubic
feet with NO PROBLEMS whatsoever. In this case, it's a higher quality
sub rated for WELL over what the amp is rated (sub is capable of 250
watts rms, same amplifier), and I didn't try to stretch the hell out of
the subs specs (subs resonant frequency [Fs] is 26 Hz, and this box is
tuned to that number almost exactly). Remember that WinISD is not
perfect; it is simply a good guide. Do not try to stretch the limits
of your woofer too much - if you go too far you'll often ruin your sub.

All that being said, nearly two cubic feet for one 12-inch sub of,
presumably, high power and quality (which, I hear JL Audio is both) is
MORE than enough in my experience. I would venture an educated guess
that the box you described would be tuned to somewhere around 23 - 25
Hz - which is lower than most people would need. What frequency are
you trying to get down to?

~The Lull
mfreak wrote:
I want to build a new enclosure, and do it right. So...

- Does it matter which face of the enclosure the drivers and ports are
on? On my current box, the ports are on the opposite face as the
drivers. An installer here says the drivers and ports should go on the
same face, which I'd rather do if there's no reason not to.

- For a 12w3v2-d2, JL 'recommends' a 1.75 cu ft box, with a 4" port
that's 15.25" long. I've been playing with WinISD, and I can get freq.
response as low as I want my making the box bigger and bigger. A JL
techy says I can make the box slightly larger to make up for some of
the driver displacement and port volume, but not to make it make it
larger than 1.85 or 1.9. They say they build and test boxes, and 1.75
IS optimal. The JL techy and the installer I talk to, neither of em
heard of WinISD, and neither trust any of 'those goofy box programs on
the internet'. The installer said he'd build it 1.75 GROSS volume.

.75" MDF is fine, right? I was planning on 1", but home depot and
Menards only sell .75. I assume that's ok, since that's what my
existing box is. Anything better to use?

TIA,

[The Lull]

Oops, almost forgot about port position.

There are a couple of important things to think about when deciding
which way your ports are going to face.

First, you're tuning your box to a certain frequency when you're
porting it. Say you tune the box to 23 Hz, like I assumed before. As
I understand it (damn, I love having to dodge you flamers), the
notes/frequencies closest to 23 Hz (in this case) come out of the ports
more than the actual subwoofer. It's not super-important, but it's
something I always keep in the back of my mind.

Next, for a simple ported design, the ports and the sub should ALWAYS
share the same airspace - unless you are making some sort of bandpass
enclosure. This doesn't mean that the ports HAVE to be on the same
side/surface of the box as the sub, but that's usually the easiest way
to ensure that this is the case. I have had good luck in making a box
where the sub fires upward, and the ports face the rear of the vehicle.
I have had excellend luck with the sub and ports all on the same side
of the box. But if you were going to, say, create a wall where your
box is seperate from the rest of your trunk - then it would not be the
best practice to have the sub firing up and the ports leading to the
trunk side of that wall.

Big Disclaimer: The above posts are pulled directly from personal
experience and knowledge I've gained from question asked, FAQs read,
and other crap in this group. If something I said is *technically*
wrong - please correct me, but for the love of god try to be civil
about it.

~The Lull
mfreak wrote:
I want to build a new enclosure, and do it right. So...

- Does it matter which face of the enclosure the drivers and ports are
on? On my current box, the ports are on the opposite face as the
drivers. An installer here says the drivers and ports should go on the
same face, which I'd rather do if there's no reason not to.

- For a 12w3v2-d2, JL 'recommends' a 1.75 cu ft box, with a 4" port
that's 15.25" long. I've been playing with WinISD, and I can get freq.
response as low as I want my making the box bigger and bigger. A JL
techy says I can make the box slightly larger to make up for some of
the driver displacement and port volume, but not to make it make it
larger than 1.85 or 1.9. They say they build and test boxes, and 1.75
IS optimal. The JL techy and the installer I talk to, neither of em
heard of WinISD, and neither trust any of 'those goofy box programs on
the internet'. The installer said he'd build it 1.75 GROSS volume.

.75" MDF is fine, right? I was planning on 1", but home depot and
Menards only sell .75. I assume that's ok, since that's what my
existing box is. Anything better to use?

TIA,

[D.Kreft]

On Oct 18, 11:30 am, "mfreak" wrote:

- Does it matter which face of the enclosure the drivers and ports are
on? On my current box, the ports are on the opposite face as the
drivers. An installer here says the drivers and ports should go on the
same face, which I'd rather do if there's no reason not to.

I concur with your installer. By placing the ports and drivers on
different sides of the box, you open yourself up to phase issues that
may or may not lead to audible problems. Remember...those ports aren't
just there to let the subwoofer "breathe"--sound comes out of them,
too, so you want to have them on the same surface as the driver
whenever possible.

- For a 12w3v2-d2, JL 'recommends' a 1.75 cu ft box, with a 4" port
that's 15.25" long. I've been playing with WinISD, and I can get freq.
response as low as I want my making the box bigger and bigger. A JL
techy says I can make the box slightly larger to make up for some of
the driver displacement and port volume, but not to make it make it
larger than 1.85 or 1.9. They say they build and test boxes, and 1.75
IS optimal. The JL techy and the installer I talk to, neither of em
heard of WinISD, and neither trust any of 'those goofy box programs on
the internet'. The installer said he'd build it 1.75 GROSS volume.

Do *exactly* what the JL techs tell you. I can assure you that the
recommendations and instructions they give you are for your own
benefit. JL doesn't just put arbitrary box specs together and say "Hey,
let's just tell people to do this because we don't have time to sit
around and test all this junk." And especially when dealing with ported
boxes, don't add "just a little" to compensate for the displacement of
the driver and the port. JL Audio provides exact displacement specs
measured in cu. ft. for every single one of their subwoofers (0.07 cu.
ft. in your specifc case:
http://mobile.jlaudio.com/products_s...es_id=12)--use them.
Also, do a little math and figure out what the exact displacement of
your ports and bracing is going to be and take that into consideration
when building your box.

As far as trusting "those goofy box programs", there's some truth to
that. Modeling the precise behavior of a loudspeaker isn't very easy.
You can get a decent idea of whether you're in the ballpark with "goofy
box programs", but ultimately a machine absolutely cannot tell you how
good something is going to sound (or how it's going to behave under
power)--you can have two plots that look very similar and have one
sound like dog meat. Additionally, unless you have received some
technical training on how to use modeling programs and unless you have
a good understanding of the trade-offs involved in design decisions,
you could very well set yourself up for failure. Simply making a box
bigger and bigger to get "whatever frequency response I want" is not a
valid way to design subwoofer enclosures.

Lastly, modeling programs cannot tell you what the driver is going to
sound like in the car. Remember that a vehicle's "transfer function"
will add a roughly 12dB SPL/octave boost starting at the frequency
whose wavelength is half of your vehicle's interior length. For
example, a car with an interior length of 12 feet would beging to boost
frequencies below about 47Hz (a 47Hz wave is about 24 feet long at sea
level), so that if your sealed-box's f3 were at 47Hz, you'd
theoretically get a nearly flat response curve below that point.

This is why subs always sound more "meaty" in a car than they do in a
home--the acoustics of the vehicle play a huge role in the overall
response of your system. If you approach your design with the mistaken
notion that "the lower the f3 is, the better my bass will sound",
you're going to be in for a rude awakening when you fire-up the system.
A super-low f3 in a vehicle can result in really awful-sounding,
imbalanced, over-powering bass that your midrange drivers will almost
certainly not be able to keep up with.

.75" MDF is fine, right? I was planning on 1", but home depot and
Menards only sell .75. I assume that's ok, since that's what my
existing box is. Anything better to use?

3/4" is fine for most applications. Make sure you brace the box very
well--rigidity is key.

You would do well to read the JL Audio box-building tutorials:

http://mobile.jlaudio.com/support_pages.php?page_id=141

-dan

[GregS]

In article . com, "The Lull" wrote:
Oops, almost forgot about port position.

There are a couple of important things to think about when deciding
which way your ports are going to face.

First, you're tuning your box to a certain frequency when you're
porting it. Say you tune the box to 23 Hz, like I assumed before. As
I understand it (damn, I love having to dodge you flamers), the
notes/frequencies closest to 23 Hz (in this case) come out of the ports
more than the actual subwoofer. It's not super-important, but it's
something I always keep in the back of my mind.

Gee, I still use a DOS program for all my stuff. Q-box.

The port at 23 hz will have vertually all the sounds, so yes,
the position can make a difference in relation to the vehicle.
I would normally like to have the ports as far back and as close
to a rear surface as possible.

greg

[mfreak]

D.Kreft wrote:
Do *exactly* what the JL techs tell you. I can assure you that the
recommendations and instructions they give you are for your own
benefit. JL doesn't just put arbitrary box specs together and say "Hey,
let's just tell people to do this because we don't have time to sit
around and test all this junk."

Thanks for the links, that's very helpful. I will go with the
recommendation. I thought maybe they give you an optimal *practical*
enclosure. Ie, if bigger is better, then optimal would be a box that
exactly fits your trunk, but make it 1.75 cuz after that the gain is
minimal for the extra volume.. OR something along those lines. I'll
do the math and calculate volumes of ports, driver, bracing, everything
and make the box's volume exactly 1.75.

[mfreak]

The Lull wrote:
First, you're tuning your box to a certain frequency when you're
porting it. Say you tune the box to 23 Hz, like I assumed before. As
I understand it (damn, I love having to dodge you flamers), the
notes/frequencies closest to 23 Hz (in this case) come out of the ports
more than the actual subwoofer. It's not super-important, but it's
something I always keep in the back of my mind.

Thanks Lull, in fact your huge box and extremely low tuning is what
made me consider making a bigger-than-recommended box in the first
place.

JL says the box they recommend is tuned to 30.8 Hz (WinISD says 32.56
with the volume/port size), with an F3 right around 32Hz. My installer
says 31 Hz is really damn low, and I was thinking 'meh.. lull is 26
with a 10' The box I have now is not even close to recommendation, so
I'm sure it'll be a huge improvement. I'm no acoustic engineer or
anything, so I'll trust the JL guys know what they're talking about and
build to their specs.

[mfreak]

Oh, and one more thing before I forget: If the ports coming out the
front face, and they're 15.25" long, then they'll be really close to
the back face of the box on the inside of the box. I'm sure there's
some minimum clearance on the inside of the box? If it was 1/8" from
the back, then it's just about not a port at all, it's just taking up
volume correct? I'm thinking 3 or 4 inches, or do i need more? Thanks
again,

[The Lull]

3 inches would be more than adaquate, but I'm not certain there's a
hard and fast rule on this (are you beginning to see the gigantic gray
area that is sub box design?).

~The Lull
mfreak wrote:
Oh, and one more thing before I forget: If the ports coming out the
front face, and they're 15.25" long, then they'll be really close to
the back face of the box on the inside of the box. I'm sure there's
some minimum clearance on the inside of the box? If it was 1/8" from
the back, then it's just about not a port at all, it's just taking up
volume correct? I'm thinking 3 or 4 inches, or do i need more? Thanks
again,

[The Lull]

Um, I'm curious...

On your Thiele-Small parameters for the sub, what's the Fs?

I would've thought that a 12-inch JL sub would be in the 20's
somewhere.

Someone (politely) tell me if I'm wrong, but I would NEVER create a
ported box where the tuned frequency is HIGHER than the resonant
frequency of the sub........

~The Lull
mfreak wrote:
The Lull wrote:
First, you're tuning your box to a certain frequency when you're
porting it. Say you tune the box to 23 Hz, like I assumed before. As
I understand it (damn, I love having to dodge you flamers), the
notes/frequencies closest to 23 Hz (in this case) come out of the ports
more than the actual subwoofer. It's not super-important, but it's
something I always keep in the back of my mind.

Thanks Lull, in fact your huge box and extremely low tuning is what
made me consider making a bigger-than-recommended box in the first
place.

JL says the box they recommend is tuned to 30.8 Hz (WinISD says 32.56
with the volume/port size), with an F3 right around 32Hz. My installer
says 31 Hz is really damn low, and I was thinking 'meh.. lull is 26
with a 10' The box I have now is not even close to recommendation, so
I'm sure it'll be a huge improvement. I'm no acoustic engineer or
anything, so I'll trust the JL guys know what they're talking about and
build to their specs.

[Captain_Howdy]

Who in there right mind would tune a port down to 23hz and why??

[mfreak]

The Lull wrote:
On your Thiele-Small parameters for the sub, what's the Fs?

According to JL at
http://mobile.jlaudio.com/products_s...p?series_id=12 the Fs is 24.3
Hz.

I would've thought that a 12-inch JL sub would be in the 20's
somewhere.

In the owners manual for that particular sub -
http://mobile.jlaudio.com/pdfs/8681.pdf the recommended slot ported box
is 30.8 Hz. I phoned JL tech support, they said to go with 1.75 cu ft,
with a round port that's 4" in diameter and 15.25" long. I assume this
would be the equivalent 30.8 Hz, WinISD reports it's 32.5 or 32.6, I
forget and don't have it in front of me now.

Someone (politely) tell me if I'm wrong, but I would NEVER create a
ported box where the tuned frequency is HIGHER than the resonant
frequency of the sub........

Assuming the given data is correct, JL apparently would, but IDK why..
Of course IDK why you don't like that idea, cuz IDK anything about box
design... I am a good carpenter tho, given the dimensions I can build
it.. That's all I DO know,

[Eric Desrochers]

Captain_Howdy wrote:

Who in there right mind would tune a port down to 23hz and why??

What kind of stupid question is this?

--
Eric (Dero) Desrochers
http://homepage.mac.com/dero72

Hiroshima 45, Tchernobyl 86, Windows 95

[D.Kreft]

On Oct 18, 1:53 pm, "mfreak" wrote:

Oh, and one more thing before I forget: If the ports coming out the
front face, and they're 15.25" long, then they'll be really close to
the back face of the box on the inside of the box. I'm sure there's
some minimum clearance on the inside of the box? If it was 1/8" from
the back, then it's just about not a port at all, it's just taking up
volume correct? I'm thinking 3 or 4 inches, or do i need more? Thanks
again,

Read the JL tutorial on box design...there's a section (or a complete
tutorial) on how to do slot (rectangular) ports. JL Audio also used to
sell some stuff called "FlexPort" which is a flexible (yet rigid) port
material. I don't know if they still offer it, though--check their
site.

Generally speaking, you want to keep the end of the port 1 effective
diameter away from any orthogonal wall...the more distance the better,
though.

-dan

[Captain_Howdy]

What part did you not understand?


In article ,
(Eric Desrochers) wrote:
Captain_Howdy wrote:

Who in there right mind would tune a port down to 23hz and why??

What kind of stupid question is this?

[The Lull]

One of the sections within that JBL informational website link posted
above (http://mobile.jlaudio.com/support_pa...p?page_id=150), gives
a much better explanation of why one wouldn't design a ported box tuned
to a frequency above the Fs of a sub (a bit of a long read, but pay
attention to the last part):

[Quote from http://mobile.jlaudio.com/support_pa...p?page_id=150]
In a ported enclosure, there is a delicate relationship between the
volume of air in the box, the resonant effect of the port, and the
parameters of the speaker being used. When these three factors are
correctly integrated, the rear output wave of the speaker is delayed
just enough so that when it comes out of the port, it is in relative
phase with the wave being produced by the front of the speaker. The
result is constructive output from the port limited to a desired low-
frequency range.
This low-frequency reinforcement is one of the big advantages of a
well-designed ported system. Using the work of the rear of the cone in
a constructive manner means that a gain in efficiency of about 3dB over
a broad band in the sub-bass range can be achieved as compared to a
sealed enclosure using the same woofer. The other big advantage is that
the interaction of the port, the enclosure and the speaker's resonant
characteristics also reduces cone motion and, therefore, distortion at
higher volume levels in the frequency range controlled by the port. The
down side is that at frequencies below the tuning of the port, the
speaker gradually begins to act as if it were not enclosed at all...
[/Quote from http://mobile.jlaudio.com/support_pa...p?page_id=150]

Here's what that last sentence means to me: If your sub ITSELF
can/will produce frequencies of 24.3 (as you stated), then your sub
will act as though it is not enclosed at all at those frequencies
which, according to all I've been told, is bad. I'm not saying that JL
doesn't know what they're talking about - I'm saying I'm a little
confused since they seem to have some contradiction going on here....

~The Lull

P.S. Howdy - As I'm sure you're aware, there is music out there that
utilizes extremely low frequencies (techno, big beat, electronic). I
have no idea what mfreak listens to, but let's pretend for a moment
that he's not you. Let's also pretend that perhaps he listens to a LOT
of music that hits these super low notes. It might be perfectly valid
to tune a ported box to 23 Hz in that case, wouldn't it? So to answer
your question - some people, and for certain types of music. Probably
23 Hz isn't necessary, true. But that was a guess on my part, and
evidently not what mfreak is going for. Therefore yours is not a
relevant question.
mfreak wrote:
The Lull wrote:
On your Thiele-Small parameters for the sub, what's the Fs?

According to JL at
http://mobile.jlaudio.com/products_s...p?series_id=12 the Fs is 24.3
Hz.

I would've thought that a 12-inch JL sub would be in the 20's
somewhere.

In the owners manual for that particular sub -
http://mobile.jlaudio.com/pdfs/8681.pdf the recommended slot ported box
is 30.8 Hz. I phoned JL tech support, they said to go with 1.75 cu ft,
with a round port that's 4" in diameter and 15.25" long. I assume this
would be the equivalent 30.8 Hz, WinISD reports it's 32.5 or 32.6, I
forget and don't have it in front of me now.

Someone (politely) tell me if I'm wrong, but I would NEVER create a
ported box where the tuned frequency is HIGHER than the resonant
frequency of the sub........

Assuming the given data is correct, JL apparently would, but IDK why..
Of course IDK why you don't like that idea, cuz IDK anything about box
design... I am a good carpenter tho, given the dimensions I can build
it.. That's all I DO know,

[GregS]

In article .com, "The Lull" wrote:
One of the sections within that JBL informational website link posted
above (http://mobile.jlaudio.com/support_pa...p?page_id=150), gives
a much better explanation of why one wouldn't design a ported box tuned
to a frequency above the Fs of a sub (a bit of a long read, but pay
attention to the last part):

[Quote from http://mobile.jlaudio.com/support_pa...p?page_id=150]
In a ported enclosure, there is a delicate relationship between the
volume of air in the box, the resonant effect of the port, and the
parameters of the speaker being used. When these three factors are
correctly integrated, the rear output wave of the speaker is delayed
just enough so that when it comes out of the port, it is in relative
phase with the wave being produced by the front of the speaker. The
result is constructive output from the port limited to a desired low-
frequency range.
This low-frequency reinforcement is one of the big advantages of a
well-designed ported system. Using the work of the rear of the cone in
a constructive manner means that a gain in efficiency of about 3dB over
a broad band in the sub-bass range can be achieved as compared to a
sealed enclosure using the same woofer. The other big advantage is that
the interaction of the port, the enclosure and the speaker's resonant
characteristics also reduces cone motion and, therefore, distortion at
higher volume levels in the frequency range controlled by the port. The
down side is that at frequencies below the tuning of the port, the
speaker gradually begins to act as if it were not enclosed at all...

Its a little confusing or misleading about the exact things that are happening.
The port and driver have a phase mismatch at the point where each is contributing.
Below this vertually all comes from the port, and the same for the upper
range, the driver has most all the output. Ported boxes don't gain efficiency, they
gain bandpass. The efficiency is set by the driver alone. Drivers that work well in ported boxes
generall have higher efficiency than an equivalant driver designed for sealed box.

I don't hear much talk about ported box types around here. It was drummed
into me from way back There are ways to describe th eeffects
of various port tunning box size. May I quote from the Loudspeak Handbook
I'm sure if discriptions were included in the book, but things like boom, or transient response,
usually are described with each configuration.

There are at least 15
well-established alignment categories, such as SSB4 ~Super Fourth-Order
Boom Box!, SC4 ~Fourth Order Sub-Chebychev!, QB3 ~Quasi Third-Order
alignment!, and discrete alignments such as the Fourth-Order Butterworth
~B4!, Fourth-Order Bessel ~BE4!, and Butterworth Inter-Order ~IB4!.

greg


[/Quote from http://mobile.jlaudio.com/support_pa...p?page_id=150]

Here's what that last sentence means to me: If your sub ITSELF
can/will produce frequencies of 24.3 (as you stated), then your sub
will act as though it is not enclosed at all at those frequencies
which, according to all I've been told, is bad. I'm not saying that JL
doesn't know what they're talking about - I'm saying I'm a little
confused since they seem to have some contradiction going on here....

Sometime a good high pass filter is recommended above the box
tunning, to preven excessive excursion and increase power handling.


~The Lull

P.S. Howdy - As I'm sure you're aware, there is music out there that
utilizes extremely low frequencies (techno, big beat, electronic). I
have no idea what mfreak listens to, but let's pretend for a moment
that he's not you. Let's also pretend that perhaps he listens to a LOT
of music that hits these super low notes. It might be perfectly valid
to tune a ported box to 23 Hz in that case, wouldn't it? So to answer
your question - some people, and for certain types of music. Probably
23 Hz isn't necessary, true. But that was a guess on my part, and
evidently not what mfreak is going for. Therefore yours is not a
relevant question.
mfreak wrote:
The Lull wrote:
On your Thiele-Small parameters for the sub, what's the Fs?

According to JL at
http://mobile.jlaudio.com/products_s...p?series_id=12 the Fs is 24.3
Hz.

I would've thought that a 12-inch JL sub would be in the 20's
somewhere.

In the owners manual for that particular sub -
http://mobile.jlaudio.com/pdfs/8681.pdf the recommended slot ported box
is 30.8 Hz. I phoned JL tech support, they said to go with 1.75 cu ft,
with a round port that's 4" in diameter and 15.25" long. I assume this
would be the equivalent 30.8 Hz, WinISD reports it's 32.5 or 32.6, I
forget and don't have it in front of me now.

Someone (politely) tell me if I'm wrong, but I would NEVER create a
ported box where the tuned frequency is HIGHER than the resonant
frequency of the sub........

Assuming the given data is correct, JL apparently would, but IDK why..
Of course IDK why you don't like that idea, cuz IDK anything about box
design... I am a good carpenter tho, given the dimensions I can build
it.. That's all I DO know,

[D.Kreft]

On Oct 18, 2:36 pm, "The Lull" wrote:

Someone (politely) tell me if I'm wrong, but I would NEVER create a
ported box where the tuned frequency is HIGHER than the resonant
frequency of the sub........

I can't comment on this directly because I'm so rusty at this, but what
I can say
is that it's never a good idea to consider just *one* of the T/S
parameters and make
judgement calls about the performance of the driver in an enclosure or
how you'd tune
it. Unfortunately, the individual T/S parameters are not orthoganal to
one another--it's
kinda like flying a helicopter--if you alter the main rotor speed, you
have to also
fiddle wtih your pedals, or you'll start spinning like a top....very
tricky (unless the
helicopter is one of them new-fangled ones that handle all these
adjustments for you
by one of them computer things).

-dan

[MOSFET]

it. Unfortunately, the individual T/S parameters are not orthoganal to
one another


ORTHOGANAL - Cool word!!!

I had to look that one up.
MOSFET

[Eric Desrochers]

Captain_Howdy wrote:

What part did you not understand?


In article ,
(Eric Desrochers) wrote:
Captain_Howdy wrote:

Who in there right mind would tune a port down to 23hz and why??

What kind of stupid question is this?


Fine formulas were put toghether more than 30 years ago. You take the
driver's T/S parameters, put them into said formulas and the ideal box
volume and port tuning are calculated for you. If the port turn out to
be tuned at 23, 20 or even 14 Hz, so be it.

THIS IS THE CORRECT WAY to determine a box tuning, if sound quality is
your goal. 45 Hz one-note-wonder are another story.

I guess my question would be what do you find to be wrong with a 23 Hz
box?

--
Eric (Dero) Desrochers
http://homepage.mac.com/dero72

Hiroshima 45, Tchernobyl 86, Windows 95

[Captain_Howdy]

There is very little music out there in the 23hz range. The lowest tone in non
electronic instrument is the A1 note on a Piano 28hz. Music has it's heaviest
bass content in the 35-65hz range. You'll even notice that most speaker
manufactures recommend port tuning frequencies of 33-40hz and a subsonic
filter setting between 25-30hz. What makes you think that a 45hz port tuning
will give you a one-note-wonder is beyond me, it's not like the port tuning
frequency acts as a subsonic filter. With that said a box with a port tuned to
23hz would be a much better example of a one-note-wonder, What audible content
are you getting below 23hz? It's a waste of bandwidth efficiency.


In article ,
(Eric Desrochers) wrote:
Captain_Howdy wrote:

What part did you not understand?


In article ,
(Eric Desrochers) wrote:
Captain_Howdy wrote:

Who in there right mind would tune a port down to 23hz and why??

What kind of stupid question is this?


Fine formulas were put toghether more than 30 years ago. You take the
driver's T/S parameters, put them into said formulas and the ideal box
volume and port tuning are calculated for you. If the port turn out to
be tuned at 23, 20 or even 14 Hz, so be it.

THIS IS THE CORRECT WAY to determine a box tuning, if sound quality is
your goal. 45 Hz one-note-wonder are another story.

I guess my question would be what do you find to be wrong with a 23 Hz
box?

[Eric Desrochers]

Captain_Howdy wrote:

There is very little music out there in the 23hz range.

If you want a full range system, you'll want to reproduce it anyway.

The lowest tone in non
electronic instrument is the A1 note on a Piano 28hz.

Yeah, but we are surrounded by electronic music all day long. Please
download "I miss you (Photek remix) by Bjork, for thremendous amount of
content in the 25-30 Hz range. Also, some big organ have 32 feet pipes,
producing a note of 16 Hz. Such music was indeed recorded. That you
can hear it is irrelevant, you can feel it.

Music has it's heaviest
bass content in the 35-65hz range.

Most of the time, yes, but exceptions are becoming the norm now.

You'll even notice that most speaker
manufactures recommend port tuning frequencies of 33-40hz and a subsonic
filter setting between 25-30hz.

What drivers and what manufacturer. I'll give you a different example.
The 12" Dayton Titanic, a popular DIY sub, when ported, needs a 3.71
cubic-feet, a Fb of 19.52 Hz, for an F3 of 18.22 Hz. This is my
definition of a full range sub. It give a box kinda big for a car but
should do wonder in a home system.

Now, I know about cabin gain and why such a deep response is not
desirable in a car. I was just arguing about the "absolute silliness of
23 Hz box" in general. Never say never, as they say...

What makes you think that a 45hz port tuning
will give you a one-note-wonder is beyond me,

I'm not saying a 45 Hz tuning is bad. I'm saying that a driver who
would need, say 28 Hz, but you decide to tune it to 45 Hz anyway would
probably be very loud but will sound like ****.

A lot of the boom box on wheels you hear are overbearing at 45 Hz with
not much below 35 Hz. That's where the expression come. I'm sure you
have heard it before?

To each its own I guess...

--
Eric (Dero) Desrochers
http://homepage.mac.com/dero72

Hiroshima 45, Tchernobyl 86, Windows 95

[Captain_Howdy]

I personally tuned my ports to 36hz, found it to be a good area for lows and
SPL. It's sounds wild with anything that I throw at it, even with a 25hz
subsonic filter. Yet it still slams 151.6db on a term-lab playing Bass
Mekanik's Tranzmekanika with the engine off running and feeding from only two
optima yellow tops. LOL On the other end of the scale it's still loud enough
turn a few heads and trigger a car alarm from time to time rocking Kiss's I
love it loud. It's even makes ABBA and Richard Cheese slam, but I don't really
want to get into that topic. I do agree that tuning too high does sound like
ass, as does tuning to low with something like a single 10 and with 150 watts
behind it.



In article ,
(Eric Desrochers) wrote:
Captain_Howdy wrote:

There is very little music out there in the 23hz range.

If you want a full range system, you'll want to reproduce it anyway.

The lowest tone in non
electronic instrument is the A1 note on a Piano 28hz.

Yeah, but we are surrounded by electronic music all day long. Please
download "I miss you (Photek remix) by Bjork, for thremendous amount of
content in the 25-30 Hz range. Also, some big organ have 32 feet pipes,
producing a note of 16 Hz. Such music was indeed recorded. That you
can hear it is irrelevant, you can feel it.

Music has it's heaviest
bass content in the 35-65hz range.

Most of the time, yes, but exceptions are becoming the norm now.

You'll even notice that most speaker
manufactures recommend port tuning frequencies of 33-40hz and a subsonic
filter setting between 25-30hz.

What drivers and what manufacturer. I'll give you a different example.
The 12" Dayton Titanic, a popular DIY sub, when ported, needs a 3.71
cubic-feet, a Fb of 19.52 Hz, for an F3 of 18.22 Hz. This is my
definition of a full range sub. It give a box kinda big for a car but
should do wonder in a home system.

Now, I know about cabin gain and why such a deep response is not
desirable in a car. I was just arguing about the "absolute silliness of
23 Hz box" in general. Never say never, as they say...

What makes you think that a 45hz port tuning
will give you a one-note-wonder is beyond me,

I'm not saying a 45 Hz tuning is bad. I'm saying that a driver who
would need, say 28 Hz, but you decide to tune it to 45 Hz anyway would
probably be very loud but will sound like ****.

A lot of the boom box on wheels you hear are overbearing at 45 Hz with
not much below 35 Hz. That's where the expression come. I'm sure you
have heard it before?

To each its own I guess...

[The Lull]

Some asshole wrote:
I do agree that tuning too high does sound like
ass, as does tuning to low with something like a single 10 and with 150 watts
behind it.

Since I'm pretty sure that last statement was pointed at me, I must
point out that besides being a prick and trying to quantify statements
that are a matter of opinion to cover your dick-headedness, you're
completely wrong. My single 10, tuned to 26 Hz, being pushed by 150
watts rms, sounds ****ing excellent.

~The Lull

[Captain_Howdy]

In fact that last statement wasn't pointed at you, not knowing much about your
system other then it being JBL, but with all of the info just given I do agree
that it must sound like ****ing something. This is where the matter of opinion
comes in to play.

In article . com, "The Lull"
wrote:
Some asshole wrote:
I do agree that tuning too high does sound like
ass, as does tuning to low with something like a single 10 and with 150 watts
behind it.

Since I'm pretty sure that last statement was pointed at me, I must
point out that besides being a prick and trying to quantify statements
that are a matter of opinion to cover your dick-headedness, you're
completely wrong. My single 10, tuned to 26 Hz, being pushed by 150
watts rms, sounds ****ing excellent.

~The Lull

[GregS]

In article , (Eric Desrochers) wrote:
Captain_Howdy wrote:

What part did you not understand?


In article ,
(Eric Desrochers) wrote:
Captain_Howdy wrote:

Who in there right mind would tune a port down to 23hz and why??

What kind of stupid question is this?


Fine formulas were put toghether more than 30 years ago. You take the
driver's T/S parameters, put them into said formulas and the ideal box
volume and port tuning are calculated for you. If the port turn out to
be tuned at 23, 20 or even 14 Hz, so be it.

THIS IS THE CORRECT WAY to determine a box tuning, if sound quality is
your goal. 45 Hz one-note-wonder are another story.

I guess my question would be what do you find to be wrong with a 23 Hz
box?

The trouble is, there are more than one formula, and box types. The sound the box
makes after its made from one of the alignments, can be categorized
from the 15 box alignment types. A good program, will ask you what alignment
you want, or provide all the various types. It should at the least, describe
the box type the computations are derived from. There was some talk in the Speaker Builder
magazine, years ago, basically saying you can also go inbetween box
alignments and come up with infinate variations.


There are at least 15
well-established alignment categories, such as SSB4 ~Super Fourth-Order
Boom Box!, SC4 ~Fourth Order Sub-Chebychev!, QB3 ~Quasi Third-Order
alignment!, and discrete alignments such as the Fourth-Order Butterworth
~B4!, Fourth-Order Bessel ~BE4!, and Butterworth Inter-Order ~IB4!.

greg

[Eric Desrochers]

GregS wrote:

There are at least 15
well-established alignment categories, such as SSB4 ~Super Fourth-Order
Boom Box!, SC4 ~Fourth Order Sub-Chebychev!, QB3 ~Quasi Third-Order
alignment!, and discrete alignments such as the Fourth-Order Butterworth
~B4!, Fourth-Order Bessel ~BE4!, and Butterworth Inter-Order ~IB4!.

greg

That's correct, of course.

But still, a box could end up with a very low tuning, be correctly
aligned and sound good.

This sub-thread started up with an arguments that very low tuning was
*always* silly.

--
Eric (Dero) Desrochers
http://homepage.mac.com/dero72

Hiroshima 45, Tchernobyl 86, Windows 95

[GregS]

In article , (Eric Desrochers) wrote:
GregS wrote:

There are at least 15
well-established alignment categories, such as SSB4 ~Super Fourth-Order
Boom Box!, SC4 ~Fourth Order Sub-Chebychev!, QB3 ~Quasi Third-Order
alignment!, and discrete alignments such as the Fourth-Order Butterworth
~B4!, Fourth-Order Bessel ~BE4!, and Butterworth Inter-Order ~IB4!.

greg

That's correct, of course.

But still, a box could end up with a very low tuning, be correctly
aligned and sound good.

This sub-thread started up with an arguments that very low tuning was
*always* silly.

I think 9 times out of ten, most go for low tunning. The only thing
bad is the tunning is more sensitive on the lower end. If you go up a bit, the
tunning is not critical at all.

greg