| DAAD (Diffusion Absorption
Acoustic Devices) |
| Building “Acropolis” at home and
how I learnt a lesson |
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|
April 2007 |

Like most audiophiles who’ve been in this
hobby for many years, I too, have tried a lot
of equipment. From vintage tube gear from
Dynaco and C-J to solid-state electronics from
NAD, Tandberg, Krell, Nakamichi, EC, etc. I
have owned large speakers from Infinity, small
Dynaudio`s, Proac`s, different Peak-Consults
etc. I have also changed more cables than I am
willing to admit, believe me.
All these years my focus has been on the
equipment and investing money where I thought
it made the largest impact on the sound. What
I have learned is that the sound changes
every time I swap gear, but that change
wasn’t always better. But of course, my system
at present communicates the music on a high
level and before my journey into the mysteries
of acoustic room treatment began I was very
pleased with the sound.
After redecorating my house and my listening
room this winter, I thought that it was time
to “get the job done” and make the last
investments into the system. Therefore, I
started to read about room acoustics on the
internet and in magazines. Previously I have
taken, as I am sure that many others have,
shortcuts as far as room acoustics are
concerned. Carpets, drapes, pillows, plants
etc. I’m not saying that such devices can’t do
anything for the sound. They may help, but
nothing can replace good theory and well
crafted products. I can say this now because I
know. There are no cheap ways to get really
good sound at home in general and room
acoustics are no exception to that rule.
This review could only happen because the
Norwegian importer Base-Technology made a lot
of efforts. That said, I have to confess that
this was a difficult review to write. One
reason was that the sound changed every time I
made any adjustments. Not much, but enough so
that I had to concentrate and play the same
cuts over and over again to verify my
findings.
One other issue here was the theory behind the
products, most of them new to me. Yes I have
heard about echoes, standing waves etc., but
never really bothered to investigate them
further. I feel like a fool now for not having
taken the time to learn more about acoustics
earlier. Well, it’s never too late.
When I contacted the importer the first time,
he asked me for a drawing of my listening
room. This is standard procedure at Acoustica
Applicata, and what I got back from them
really told me that they are serious about
what they are doing. I got three drawings, all
from different angles with placement
recommendations and indications of the
reflective patterns from the speakers. Let me
say this at once; what they recommended proved
to be very close to the perfect placement in
my room. Even the angle on where to point the
reflective and absorbing (it is marked on the
DAAD`s) sides were right. Not bad when all
this was based upon my primitive drawing. So,
trust these people, you are in good hands.
The DAADs (Diffusion Absorption Acoustic
Devices) have a wooden plate on the top and
bottom and their fit-n-finish is very good.
They come in three different colors (white,
grey, and black) and sizes:
The DAAD 2™ is for resonances at 120Hz and
over, and for early lateral and back
reflections.
The DAAD3™ is for resonances at 70Hz and over,
and for all kinds of early reflections.
Finally, the DAAD4™ is for resonances at 50Hz
and over, and for early anterior reflections.
On their website I found a very enjoyable
article about how these Italian enthusiasts
created the DAAD products. The following text
is taken directly from this article. I mean,
who could better describe their theory and
products than themselves?
“In order to get what we wanted, we had to
experiment with other materials and
thicknesses that allowed air to penetrate the
trap quickly and get out again after a given
time. These new materials shouldn’t create
excessive friction to the air passing through
them, in order not to slow down the
functioning of the entire acoustic device with
regard to the timing of music transients that
follow each other. What we wanted was a ‘fast’
trap!
After some substantial additional research we
finally found a satisfactory combination of
two materials. At that point (we were in
1998), we had found two important ingredients:
the micro-pressed reticulate for the cover
grille and an interesting combination of
materials for the resistive layer inside.
Apart from being extremely interesting from an
acoustic point of view, these two materials
offered other important practical advantages.
The micro-pressed metal sheet looks better and
is easier to clean than the cloth covering
Tube Traps. The new resistive material inside
doesn’t dust and, therefore, doesn’t need to
be wrapped in a protective mantle like glass
wool in Tube Traps. So all we had to do now
was to define the final shape of our new
acoustic device.
The shape of a lobe seemed the most suitable
one, for the following reasons:
“The shape of a lobe seemed the most suitable
one, for the following reasons:
1. its internal volume being equal to a
cylinder, a lobe-shaped device ‘penetrates’
the corners of a room more deeply, thus
capturing the resounding frequencies more
easily;
2. its shape facilitates the simultaneous
use of different materials for the resistive
layer of the device;
3. like a cylinder, but unlike a flat panel, a
lobe device allows one to have an inner volume
with air and a thickness able to create
‘acoustic shade’. In other words, it provides
a very good ratio between the space used and
the results that are reached;
4. like a cylinder, but unlike a flat panel, a
lobe device can be rotated on itself. Having
lobes with different diffusion characteristics
allow one to position them in several ways and
to change room acoustics according to one’s
personal needs or tastes”.
All we had to do now was to find the right
ratio between the thickness of the resistive
material and the degree of ‘permeability’ to
air of the pressed metal sheet. Listening
tests and further changes to our prototypes
followed each other at a very fast pace. We
focused mainly on some specific issues: the
quality of the reproduced voice, which had to
be open and clear, without halos (and here the
rendering of vowels was particularly
important); the sensation of air, freedom, the
opening of the soundstage; the lack of boomy
low frequencies and of muddy sound in the heat
zone (100-300 Hz)”.
If you are interested you can read the whole
article
here:
Building
Acropolis at home

I have a dedicated listening room and can
really do what I want in it. And that’s a good
thing because setting up a lot of DAAD`s in a
room certainly makes a visual impact. That
said, they blended very well into the room,
though I still wasn’t sure if I really want to
have this kind of product in my living room.
Well, let me be honest with you: My wife would
not allow it either!
My room is about 5.5 meters long and 4.5
meters wide. The ceiling is 2.3 high. I have a
massive wooden floor with a large oriental
carpet in front of the system. The walls are
made of wood and the only furniture I have is
my listening chair, a CD rack and some low
bookshelves. I have some plants behind the
speakers, for decoration purposes.
The ideal listening room needs a touch of
reverb to prevent the room sounding
unnaturally dead. I know. I have experienced
this once with an overdose of acoustic
treatment in combination with heavy
wall-to-wall carpet. The sound was absolutely
lifeless. So keep in mind that all things
acoustical must be done with some help from
experts. By all means, try it for yourself,
but do not expect a miracle.
The
importer brought eight DAADs to my house. We
followed the instructions given to us by the
manufacturer and the result was visually
somewhat “Acropolistic.” In the corners,
behind the speakers, one DAAD 3 was stacked on
top of a DAAD 4 and reached from the floor to
the ceiling. On both sides of the rack we
placed one DAAD 2 and two DAAD 2s directly
behind the rack, again from the floor to the
ceiling. Remember that this is by no means a
full treatment. For that you need also to
treat the sides of the room and of course the
area behind the listening position. With a
full treatment my guess is that the results
are even better than what I got in my room
during the review period. I will try to do a
follow up later. But if you can afford (and
can live with) the full package, go ahead!
The
lesson
The first thing I noticed when we finished the
set up and fine tuning was that human voices
sounded much more natural and soft. This was
clear right from the outset when I talked to
the importer who helped me with the
installation. Being unaware of my acoustical
problems this was a real surprise. I thought
that my room was ok (but by no means perfect)
because the room is rectangular, has some
angels, a big carpet on the floor, plants and
so on. Well, I was wrong and somewhat naive.
Echoes, bass issues, standing waves and a
somewhat uneven balance proved to be areas
where the biggest challenges were.
When I started playing music, it was amazing
how the soundstage got wider and deeper, the
highs became more extended and natural, and
bass became fuller and better defined. Much
better that is. With the DAADs in place the
bass had terrific extension; it was tighter
and more controlled throughout the entire bass
range and as transparent, articulate and quick
as I've ever heard in my room.
The midrange was more natural and transparent
than ever before. Not too much, not too
little, just right. Everything was delivered
with a particular neutrality and ease. Voices,
speaking and singing, were also improved. Some
female voice can be very intense. With the
DAADs installed voices were still very
present, but better sounding without any ruff
edges. The sound of a piano when played hard
and loud was much better because of the
improved room acoustics. All in all,
everything sounded more convincing than
before. And that is what we aim for right? The
amazing thing was that I got improved sound in
all parts of the frequency range.
As I said in the beginning of this story the
advice given by the manufacturer was spot on.
I tried to turn the DAADs just a few degrees
left or right, lift them up from the floor and
tried different locations. I always ended up
like I started.
With all the DAADs I had on hand in the room
the improvement in the sound was very easy to
hear with all kinds of music, no need to
bother you with any more “audiophile jargons”,
you know them too well. So, I realized that I
had to buy some myself but I did not
want the full package. The next project was to
find the smallest amount of DAADs to get a
significant improvement in the sound without
having to fill up the room. And to drain my
bank account completely. It has suffered
enough over the last few years.
Therefore,
app. 2 weeks into the review period I started
to experiment with placements and the
reduction of DAADs. The question was this: Do
you have to buy the full package or can
improvements in room acoustics also be had by
a smaller number of columns? The answer is
fortunately; yes, you can. To try to see what
was possible for a smaller investment I
removed 2 of the DAAD 3 I had on top of the
no. 4 in the corners behind the speakers. Then
I removed one of the DAAD 2 I had behind my
rack and both DAAD 2 that stood against the
back wall.
Now I had (and still have!) the following: One
DAAD 3 in each corner behind the speakers, one
DAAD 2 directly behind the rack and one DAAD 2
on the left wall to deal with early
reflections. On the right side of the system I
have large drapes so the DAAD 2 on the left
side helps to balance the sound and stabilize
the soundstage.
I came to this set up after I had carried
DAADs in and out of the listening room for
hours playing the same 3 pieces of music.
Interesting it may have been, but boy was I
happy when I finally came to the end result.
With this “light” set up I got about 80 % of
the performance for 50 % of the price. I got
improvements all over, but of course to a
somewhat lesser degree. It is with audio as it
is in life, you have to compromise. I found a
solution that works fine in my room at
present, maybe I will take it to the next
level later on.
This experience tells me that it is important
to have an open mind about all things in
audio. Never take it for granted that you have
got the most out of your system before you
(within your limits) have tried different
options. Every audiophile that invests time
and money into a system MUST treat the room
properly, it is that simple.
“Every
listening room should have some”.
The DAADs are great tools for the fine tuning
of a system. Much unlike what happens when you
change electronics these products really make
the sound better, not just different. Be
humble enough to let the experts (in this case
from Acoustica Applicta) help you make your
system sound better. I feel I have squeezed
out what I can from my system as it is now,
and that is a good feeling. These products are
highly addictive. Consider yourself warned!
Jan Petter Egidius
__________________
Manufacturer info:
Acustica Applicata
Via Roma, 79 – 55027
Gallicano (LUCCA -ITALY)
Tel. +39 0583 730322
Fax +39 0583 730914
E-mail
info@acusticaapplicata.com
Website
www.acusticaapplicata.com
Norwegian importer:
Nordic Sound Design
Norway
Website
www.base-technology.com

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