WIDE-BAFFLED
SIDE-VENTED
REAR-LOADED BACK-HORN
FULL-RANGE-SINGLE-DRIVER
SPEAKERS
using the http://creativesound.ca
FR125S
"PAWO"
The http://creativesound.ca
FR125S
is a smooth, detailed, spacially accurate driver that can successfully
cover the full range from treble to bass. The FR125s is especially
successful at conveying musical emotion as communicated by the
gradiations of soft and loud dynamic nuances. In the "Pawo" cabinet, the bass is very robust, yet without
a midbass emphasis. One may click on the plan picture for a larger presentation.
For professionally drawn design plans with metric conversion http://www.planet10-hifi.com/tom-zHorn.html
(thank you Dave Dlugos! And for other designs using the CSS FR125S http://www.planet10-hifi.com/boxes.html). I have also adding a wider base to the cabinet for greater stability and
in order to raise the speaker to desired height.
This PAWO design has been used by others with a variety of drivers,
some reported to sound better in this cabinet than the FR125S--which is
said to be hollow in the upper midband. The drivers mentioned are some
4 inch drivers by d'Charles Audio and the Fostex FE127. See:
http://fullrangedriver.com/forum/viewtopic.php?id=573 I
personally have not tried these and have since moved on to prefering
OPEN BAFFLE speakers.
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***The following experiences have been employed in the design of"PAWO" speaker cabinet.***
THE HORN PATH: A longer path makes for a deeper roll off, a deeper
emphasis in the bass. Think of the slide of a trombone. It is doubtful
that rounded curves in the path make a difference, since the sound
waves are long & wide bass frequencies.
THE HORN MOUTH (THE VENT): A bigger mouth makes for a louder bass. But
if the mouth is located near the floor, side wall or back wall, these
junctions become part of the mouth.
THE MOUTH'S POSITION: If venting to the rear, the bass is reinforced by
the back wall, but if the speaker is too far out from the wall, the
bass can sound disconnected and distant. If venting to the front, there
are phase problems that are heard as blurred midbass when the drivers
front and rear (after passing through the path) wave are propagated
together. If venting to the side, there is a compromise that can make
use of side or back walls; this is my preferred position.
THE CHAMBER BEHIND THE DRIVER: If the chamber is shallow, as in
all Fostex designs as well as the Jordan VTL, much of the treble can
bounce back through the driver, so some damping material is called for.
If the chamber is deep, more of the midrange can bounce back. I've
tried a funnel shape as a compromise, but now think that the shallow
chamber with damping material might be best. The sound bouncing around
in this chamber does come back out through the driver (unless the
driver is mounted in an open baffle), and this sound takes on the shape
of the chamber, sometimes with musical image that is often described as
boxy. Presently, I like a shallow & wide chamber with little, if
any parallel sides. If little damping material is used the sound is
bright and lively, or if much damping is used, dull; thus the amount
must be adjusted to match the sound of the amplifier etc.
THE BAFFLE: The baffle to which the driver is mounted can be narrow or
wide. Having employed a couple of drivers into extremes of both, I hear
a narrow baffle as projecting a more precise image location, but if the
speakers are not located well away from side and back walls (more than
a yard), the melodic line suffers. It suffers because the musical
pitches are distorted as they reflect from room furnishings. Thus I
prefer a wide baffle of at least a twelve inches. With a wide baffle,
musical pitch is more stable--especially true of center stage sounds
that emanate from both stereo speakers. With a wide baffle, the music
comes through smoother, more accurate, easier to listen to. With a wide
baffle more of the sound energy is directed to the listener, thus the
volume control can be turned down a notch. Finally, with a wide baffle,
room positioning is not very critical, allowing for placement very near
to a rear wall.
