DIGITAL & ANALOG CONNECTION BLOCK DIAGRAM
one of the A-DIMENSIONAL SUBATOMIC PARTICLE complete passive ACCELERATOR (ACCELERATORE ADIMENSIONALE) for SPDIF data transmission used into the audio room
double horn SUBWOOFER
DIGGING the HOLE for the SUB WOOFERS - more than 60 cubic meters
HORN SUBWOOFER: chamber building. The horns have been designd to obtain a very narrow low pass filter
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.
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
(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)
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
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
Royal Device ® - Busto Arsizio - ITALY - Tel/FAX +39 0331 351692
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