Discussion:
Whats your preferred box type for heavy bass - sealed or ported?
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B***@spamnomore.ca
2006-01-02 02:24:08 UTC
Permalink
I've noticed a few types of boxes in use... sealed, usually with a compensating
amplifier, and ported, either with a conventional port hole or a rear horn
loaded affair... usually bigger boxes.

I'm looking at systems for anything up to gymnasium size, dance and hip-hop.

For the smallest and most economical portable system, which types would you go
with?

Thanks!
Greg Cameron
2006-01-02 02:41:41 UTC
Permalink
Post by B***@spamnomore.ca
I've noticed a few types of boxes in use... sealed, usually with a compensating
amplifier, and ported, either with a conventional port hole or a rear horn
loaded affair... usually bigger boxes.
I'm looking at systems for anything up to gymnasium size, dance and hip-hop.
For the smallest and most economical portable system, which types would you go
with?
Thanks!
Bass reflex designs (tuned port) tend to be the most economical and
compact, which is why there are so many of them on the market. For a
horn design to behave like a true sub, it has to be rather large, and
generally pretty expensive. A lot of lower cost "sub" horns don't
really go low enough to be a true sub, and often they are tuned to get
loud at one frequency and add enough distortion to create "one note
bass." Good sub horns are not cheap and not small.

Infinite baffle (sealed box) designs don't have a tuned port to augment
the bottom of their range like a reflex cabinet, so you're loosing
output in that last octave with a given amount of input power compared
to similar box with a port. I don't know of any contemporary sealed
subs for P.A. purposes.

Horns are much more efficient then a standard reflex design so you can
use less to accomplish similar output levels. The bottom line is that
you can do giant sized venues with standard reflex boxes if you have
enough of them. But you take a hit not only in number of boxes
required, but also the number of power amps which can mean higher cost.
Still, they are the most commonly used design.

Greg
Phil Allison
2006-01-02 02:51:37 UTC
Permalink
Post by B***@spamnomore.ca
I've noticed a few types of boxes in use... sealed, usually with a compensating
amplifier, and ported, either with a conventional port hole or a rear horn
loaded affair... usually bigger boxes.
I'm looking at systems for anything up to gymnasium size, dance and hip-hop.
For the smallest and most economical portable system, which types would you go
with?
** A " bandpass " box gets you the best "bang for buck" by far.

The driver is mounted on an internal baffle while dBs come out a port hole.

The box can be ridiculously small, cone excursion is at a minimum plus you
get a LPF for free.

Have you downloaded " WINisd " ????

http://www.linearteam.dk/





........ Phil
B***@spamnomore.ca
2006-01-02 06:02:02 UTC
Permalink
Post by Phil Allison
Post by B***@spamnomore.ca
I've noticed a few types of boxes in use... sealed, usually with a compensating
amplifier, and ported, either with a conventional port hole or a rear horn
loaded affair... usually bigger boxes.
I'm looking at systems for anything up to gymnasium size, dance and hip-hop.
For the smallest and most economical portable system, which types would you go
with?
** A " bandpass " box gets you the best "bang for buck" by far.
The driver is mounted on an internal baffle while dBs come out a port hole.
The box can be ridiculously small, cone excursion is at a minimum plus you
get a LPF for free.
Have you downloaded " WINisd " ????
No, I have to say I've been out of touch with live sound for quite a few years,
and have to come up to speed...

Thanks for your advice - Happy New Year to you Phil, and I hope this year things
go better for all of us!
Post by Phil Allison
http://www.linearteam.dk/
........ Phil
Peter Larsen
2006-01-02 05:11:11 UTC
Permalink
Post by B***@spamnomore.ca
I've noticed a few types of boxes in use... sealed, usually with a compensating
amplifier, and ported, either with a conventional port hole or a rear horn
loaded affair... usually bigger boxes.
I'm looking at systems for anything up to gymnasium size, dance and hip-hop.
For the smallest and most economical portable system, which types would you go
with?
Smallest: bandpass reflex as Phil suggested, most economical probably:
JBL 4520, two pairs will do for a gymnasium, best performance: front
horn.

For a simple guideline: the smaller the box(es) the bigger the amp, put
your dollars where it is most efficient for you to use them.

The 4520 is only economical if used up to 800 Hz so that you can skip
also getting low midrange boxes, not all 15" units may qualify for that
task and not all currently available midrange horns and drivers qualify.
Post by B***@spamnomore.ca
Thanks!
Kind regards

Peter Larsen
--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
Greg Cameron
2006-01-02 06:01:34 UTC
Permalink
Post by Peter Larsen
The 4520 is only economical if used up to 800 Hz so that you can skip
also getting low midrange boxes, not all 15" units may qualify for that
task and not all currently available midrange horns and drivers qualify.
Not a particularly good sounding box, especially if you cross it up
that high, though it may be loud. I for one am glad it's dead and
buried ;-) Also a beast to drag around. I hear they're still popular in
the reggae circles. What year did JBL stop making those anyway?

Greg
Peter Larsen
2006-01-02 11:00:13 UTC
Permalink
Post by Greg Cameron
Post by Peter Larsen
The 4520 is only economical if used up to 800 Hz so that you
can skip also getting low midrange boxes, not all 15" units
may qualify for that task and not all currently available
midrange horns and drivers qualify.
Not a particularly good sounding box,
Depends on build quality, on proper placement of damping and on array
construction, a pair should be on their side so that the 15" units form
a vertical column, put them side by side and midrange will suffer from
combfiltering due to interference patterns.
Post by Greg Cameron
especially if you cross it up that high,
Depends on the unit you put in it, it had better not have a midrange
problem, it is however quite correct that it is better to cross it over
at 250 Hz. In the context I think it will do just fine.
Post by Greg Cameron
though it may be loud.
Yerp, and the requirement was to fill a standard school gymnasium with
sound, 4 of those, 2 each side, and suitable tops will do that
reasonably.
Post by Greg Cameron
I for one am glad it's dead and buried ;-)
There are smaller boxes around, they just need more amplifier power.
Some of the time that will be a better choice.
Post by Greg Cameron
Also a beast to drag around.
Technique, technique, but it requires two persons to lift them, yes.
Post by Greg Cameron
I hear they're still popular in the reggae circles.
So it appears from the carneval pictures from London.
Post by Greg Cameron
What year did JBL stop making those anyway?
Mid to late 1970's, JBL's own version was btw. not a good build and did
not sound as good as they could, wood is expensive to haul around also
for the box builder. The horn design is however in my opinion good, it
just need to be built well. A sandwich board with MDF center and plywood
outer layers could be a good idea. Of course, it did take an array of 4
of them to compete with a large Duelund horn in terms of downwards
range, but that was because of horn length issues.

What did them in was mostly SPL demands, the Martin 215 bin put twice as
many 2205s in the same array area with slightly higher efficiency and
was safer to stack, but did not have the same downwards range.
Post by Greg Cameron
Greg
Kind regards

Peter Larsen
--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
Peter Larsen
2006-01-02 14:09:14 UTC
Permalink
Post by Greg Cameron
Post by Peter Larsen
The 4520 is only economical if used up to 800 Hz so that you
can skip also getting low midrange boxes, not all 15" units
may qualify for that task and not all currently available
midrange horns and drivers qualify.
Not a particularly good sounding box,
Erm, ooops, sorry about the confusion, all mine, I meant to refer to the
4530, the single 15" bin.


Kind regards

Peter Larsen
--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
shannon
2006-01-02 20:49:20 UTC
Permalink
Post by Peter Larsen
Post by Greg Cameron
Post by Peter Larsen
The 4520 is only economical if used up to 800 Hz so that you
can skip also getting low midrange boxes, not all 15" units
may qualify for that task and not all currently available
midrange horns and drivers qualify.
Not a particularly good sounding box,
Erm, ooops, sorry about the confusion, all mine, I meant to refer to the
4530, the single 15" bin.
Kind regards
Peter Larsen
The 4520 is a single 15 scoop, the 4530 is the double 15 scoop.
The 4320 studio monitor with a K140 made a decent drumfill, we had a
version that Clairs built
Peter Larsen
2006-01-02 21:08:05 UTC
Permalink
Post by shannon
The 4520 is a single 15 scoop, the 4530 is the double 15 scoop.
The 4320 studio monitor with a K140 made a decent drumfill, we had a
version that Clairs built
See:

Loading Image...


Kind regards

Peter Larsen
--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
shannon
2006-01-02 22:14:55 UTC
Permalink
Post by Peter Larsen
Post by shannon
The 4520 is a single 15 scoop, the 4530 is the double 15 scoop.
The 4320 studio monitor with a K140 made a decent drumfill, we had a
version that Clairs built
http://www.lansingheritage.org/images/jbl/catalogs/1971-pro/page05.jpg
Kind regards
Peter Larsen
mybad
I've owned them before, back in the 70s
These days I'd use 2 neo 15s in a ported cab in preference
mcsteve
2006-01-02 23:26:08 UTC
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B***@spamnomore.ca
2006-01-02 06:35:48 UTC
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On Mon, 02 Jan 2006 06:11:11 +0100, Peter Larsen
Post by Peter Larsen
Post by B***@spamnomore.ca
I've noticed a few types of boxes in use... sealed, usually with a compensating
amplifier, and ported, either with a conventional port hole or a rear horn
loaded affair... usually bigger boxes.
I'm looking at systems for anything up to gymnasium size, dance and hip-hop.
For the smallest and most economical portable system, which types would you go
with?
JBL 4520, two pairs will do for a gymnasium, best performance: front
horn.
For a simple guideline: the smaller the box(es) the bigger the amp, put
your dollars where it is most efficient for you to use them.
The 4520 is only economical if used up to 800 Hz so that you can skip
also getting low midrange boxes, not all 15" units may qualify for that
task and not all currently available midrange horns and drivers qualify.
Post by B***@spamnomore.ca
Thanks!
Kind regards
Peter Larsen
I have some boxes like that - single driver models - now have peevee BWs in
them...

Any idea how to pick a suitable replacement driver? I would guess they need low
Q speakers, around Qt = 0.38, but I don't know the Rs or Vas suitable...

I have no info here on horn loaded or band pass boxes, although Phil pointed me
to something for band pass and reflex. I already have a spreadsheet I wrote
years ago to do Small-Thiel equations.

Thanks and Happy New Year!
Bailey The Dog
2006-01-03 22:54:21 UTC
Permalink
Check out the TD218S by Community. Great sounding box for the price
<$1000.00 I use two of these with my primary system and find there to be
more than enough bottom end for even large gyms.

http://loudspeakers.net/main/index.php?option=articles&task=viewarticle&sid=46
Post by B***@spamnomore.ca
I've noticed a few types of boxes in use... sealed, usually with a compensating
amplifier, and ported, either with a conventional port hole or a rear horn
loaded affair... usually bigger boxes.
I'm looking at systems for anything up to gymnasium size, dance and hip-hop.
For the smallest and most economical portable system, which types would you go
with?
Thanks!
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