|
HORN SUBWOOFER
The SUBWOOFER efficiency is 120dB/ 1 Watt/1
meter.
So the need of external regulation to adapt
to the remaining audio system. The total electrical capability of the
16 x 48 cm woofers is about 400 W peak power per woofer that means about 400 x 16 =
6400 W peak total (practically uselss). Each woofer features a 100 mm coil. The real maximum power
fed to both subhorn measured with an oscilloscope at the highest musical
peak was 6 watts per channel when a pair of tube amps were used to drive the
16 LAuras, while up to date the electric power can reach 60 watts per
channel using the 4 x 50watts/ch BLU EYES amps. In this conditions, peak
levels are much higher and undistorted than any live concert at all. Walls
and ceiling seems to fall down, but fortunately don't. The sound pressure is
concentrated at the listening point and stopped by a 2 meters high woolglass
anechoic wall on the back of the listening position. We should remember that
the total diaphragm surface of the woofers is 2.89 square meters (8.67
square feet) and with the drivers horn loaded (not direct radiating),
distortion at 60 watts is practically negligible. If for instance the real maximum rated power (6400
watt) would be used the pressure level would reach 160 dB, but I wonder who
could survive. Not even the house built in steel & concrete maybe would
stand up.
SUB-WOOFER
Compression chamber closure ( 120 Kg on 3,6 mq) are held
and reinforced by an extra weight of 600 Kg. Total closure
weight 720 Kg.
double horn SUBWOOFER
DIGGING the HOLE for the SUB WOOFERS - more than
60 cubic meters
SUBWOOFER
chamber building
HORN SUBWOOFER: chamber building. The horns have been designd to obtain a
very narrow low pass filter
HORN SUBWOOFERS MADE IN BRICKS
In Italy all the houses
are made in bricks and not in wood as normally made in other
countries so it is easier to do and sometimes cheaper. But out of
this the very big problem is the compression chamber of the horn.
The pressures here are very high and the compression chamber
itself will resonate and the same is for the back volume of the
SUB Woofers. This will give big problems. You could surely ear a
BOOM BOOM coming out there instead of coming from the mouths (with
its own coloration) and this is not controllable unless you are
able to hold and fix steady everything. With very very big SUB
horn this is quitly impossible.
Where we did put wood (the
closures of the compression chambers) 2" thick multilayers
reversed one to the others and 2 " anti resonating material
fixed on the wood itself plus everything fixed on the 6 mm metal
borders also fixed into the concrete borders with N.16 X 8 mm
screws per each closures ( 4 closures) plus a fixing in the in
the center of each closure towards the underneath floor, well we
had problems. To make the closures not moving ( nearly at all or
let's say no more earable) and remove resonances we had to put
700 Kg staff on it, it is the pink pavement you see in the photos
with a carpet on the top.
Remember this and be
careful in building big sub horns.
10 Hz FULL POWER
An error normally made is
to consider the speaker by itself (or the amp or the cable).
There is people that do not sleep at night because still is not
satisfied of what he has made or bought. The final result of an
audio system is proportional not to the money spent to make it,
but to the amount of thinking and research one does consider
from the start as the all lot of components he must at the end stuck
together. As normally HI-END Audio manufactures do not provide
everything and people likes to put "this" connected
to "that" because " have read here and there"
or "heard from somewhere else" still the problem to get a
very good final result is far away to achieve.
Many times to build bass
horns everybody follows manual and books (and thats good to do,
theory always teaches, experience is something else), we also
have books but experience is much more worth and in this case the
horn MUST not be seen by itself.
Talking about a BIG HORN
SUBWOOFER there is something that I think people normally forget
or do not take into consideration (and maybe books do not explain) that is the dimension of the room and the position of the
horn mouths toward the listening point plus the shape of the room.
The second thing is that the bass or sub horn calculations are
normally valid (as usual) in open air and that the room itself,
if correctly used and shaped, can be considered part of the total
horn below frequencies as 20 Hz.
Due to these factors a sub-horn
that is designed on paper to have the low frequency cutoff at 30
Hz could reproduce also 10 Hz as well or even better than 30 Hz ( I
mean in amplitude), if the mouth of the horns are placed in a
correct way (we are talking of sub horn not bass horn - a bass
horn is normally designed to be placed where the loudspeaker is,
reproducing all the bass frequency range and cut in the range
of 350 - 600 Hz. A sub horn instead will reproduce starting from
"as low as possible" up to 50- 80 Hz only and can be
placed sometimes where you like (if you can of course). The room dimensions are effectively important in the very low range, so it
is for the mouth positioning. If you try to calculate (for our
Audio Room) the lenght of the wave starting from the throat of
the SUB horn to the listening point you will understand what I
mean. If you have been looking seriously at the final photos of
the Audio room, maybe you will also have noticed that the frontal
exponential panels of the frontal speakers are placed where the
horn mouths are. These panels effectively continue the horns
after sound comes out from the floor at frequencies below 25 Hz.
On the ceiling (on the top of the mouths) there is another
folding too. On the listening position there is the last folding
on the top of the sofa (maybe this is not visible on the photos).
Other foldings are in the back corners.
It is important to get the
maximum from the room. In our room, when you play Jurassic park
cinema track, when there is the dynosaurous coming, you orribly
feel all the walls crashing down (many people got scared, now I
normally ask if they are ready to be scared) is something that
you cannot even get in a cinema show, this is because all the
frequencies (low bass also) are focused all to the listening
point, while in any cinema show you normally are not able to do
it. The full 10 Hz frequency response depends on this. 5 Hz we
cannot measure, but you can feel them easyly on your body. 30 Hz
is lower in amplitude because of the phase of the emission made
by the frontal speakers bass horn. Nothing in this Audio room has
been done by a case and this is one of the topics that has been
well thought before building it.
If you have a look to the
room again you will notice that it looks like that horns are
continuing after the sub horn mouths for 10-20 Hz frequency range.
The room itself as it has
been shaped is a horn below 20 Hz, then actually the holes in the
floor are not really the final mouths below this frequency and
the length from the throat to the listening position is half of a
wavelength of 10 Hz. That is why we are getting response down to
10Hz better than 30 Hz.
SUBWOOFERS: one section shown
SUBWOOFERS: two
sections shown
SUBWOOFERS: one section shown
top view
- before making the floor
The RD Audio Room during
set-up in the year 2000
The AUDIO room is 6.95 x 8.70
meters
Woofer mounting phase into the SUBHORN
compression chamber
The compression chamber of the SUBHORN: Subwoofer connection
Into the compression chamber of the SUBHORN with the 16 woofers
assembled
(1.0 meters deep + 20 cm concrete floor on the top)
 
View of the right & left side
woofers
HORN SUBWOOFER:
Into the compression chamber of the
SUBHORN
ONLY one SECTION SHOWN - in the front: the
horn throat - View of the left side woofers (partial)
The UPTODATE Royal Device Audio and AUDIO-VIDEO room
the AUDIO ROOM has been completely reviwed since sept. 24
- 2010
and upgraded to the
AMPLIFICATORI
QUANTICI in March April 2011
on
the top
DAC
QUANTICO (with internal
DELTA POST
ACCELERATOR),
CD
PLAYER witn internal PRE ACCELERATOR for SPD-IF
data transmission
Frontal channels (LEFT + RIGTH) 8
LAURA
speakers
stereophonic tridimensionality on 3
different planes
springs (molle) underneath the Royal Device player and air vacuum (camera
d'aria)
3 x DAC QUANTICO, 3 x
A-DIMENSIONAL ACCELERATORS and QUANTIC amplifiers
The volume regulation is obtained
by passive motorized and sincronized potentiometers
block diagram
view of the 3
A-DIMENSIONAL SUBATOMIC PARTICLE
ACCELERATORS invented by Roberto Delle Curti, connected
between the SPD-IF output of the DVD /CD player and the DAC VERO
ASSOLUTO digital to analog converter
LAURA MK3 made in pear tree solid wood -
Italian fashion for the real sounding music stage
The STEEL & GLASS preamplifier today is
used only for SUB connection
|
|
the
A-DIMENSIONAL
SUBATOMIC PARTICLE
ACCELERATORS invented by Roberto Delle Curti, is connected
between the SPD-IF output of the DVD /CD player and the DAC VERO
ASSOLUTO digital to analog converter. It is a TIME MACHINE that returns back
in time, restoring completely the recording by eliminating all the
distortion accumulated by the recording processing. It is completely
passive, no power feeding.
Any type
of talking is useless. It has to be heard.
The AUDIO
obsolescence is where this is not used.
 |
|
|
|
full tri-dimensional SOLE
stereophonic set-up, on 3 different deep vertical planes (SUBWOOFER included) on
AUREA section distances withou using any electronic effect or dolby surround
|
SUB
SUB
LF LF
LF LF
LF LF
RF RF
L
R
A
listening point
|
|
4 traces oscilloscope as monitor UP and DOWN (left & right) |
the 2 internal traces are the SUBWOOFER monitors |
 |
 |
Royal Device 100+100 WATT solid state using subsonic passive analog
filter 5 a 30 Hz 24 dB/slope
PREAMPLIFICATION:
NO PREAMPLIFIER USED at
ALL.
CABLES:
SUPER EPIGENETIC CABLES
MONITORS:
1 x 4 traces
Hitachi 100 MHz Oscilloscope
1 x Pioneer SPECTRUM
ANALIZER .
2 X DAC QUANTICO
internal digital OSCILLOSCOPES
|
|
View of the
TOTAL HORN
It
has to be considered also CEILING FOLDINGS and SIDE WALLS FOLDINGS plus BACK
WALL as last folding. For this purpose on the ceiling angle toward the
vertical walls we have some wood air folders (see figure).
At the
listening point (sofa) air pressure is stopped by 2,2 meters high and 1 meter thick glass wool cubes to avoid
sofa to vibrate too much. Antivibrating foam cubes also under the sofa. The
2 LAURAs in the middle of the room are for TRI-DIMENSIONAL STEREOPHONY. They
are positioned at half lenght from the frontal and central speakers. The 4
Lauras speakers used as central channel are placed on the back of the two
internal wood side panels (see next figure where they are indicated by the
"C" letter and 2 arrows) |
|
 |
 |
|
|
|
 |
 |
|
The TOTAL HORN
hope to
have given interesting material by drawing also the underneath horn design (only
one section shown)
TOTAL
LENGHT OF THE HORN is roughly 9,3 + 2,7 + 6 + 2,5= 20, 5 meters (61,5 feet:
the full waveleght of the 16 Hz sound wave, half the wave of 8 Hz) - click
for the
COMPLETE TOP VIEW - lette C
indicates the 2 speakers of the left central channel |
|
 |
|
