Dear Troels,
after a few months I managed to finish the construction of the
Faital3WC-12 kit.
I'd like to tell you a story with a happy ending ...
As already written, I have been following you for many years and I got
to appreciate a couple of your projects built by my friends. Another
important premise is that I am a poor man and that my listening room is
small. I live in an apartment in a big and noisy city like Rome.
My latest speakers, called Funspeaker, are a two-way with 10-inch
professional midwoofer. The system featured 93-94 dB of efficiency and
an easy impedance modulus, min. 6.4 Ohm.
This is why I wrote to you that the Faital3WC was the speaker I wanted
to design. For me, my small room and my poor budget a definitive
speaker.
I managed to make the boxes very cheaply and using 18 mm birch plywood,
in sheets of about 150x150 cm. Wood and cuts (a friend helped me with a
CNC machine) cost only € 200.00, assembly and finishing are my work.
I made a floor version with a net volume of 75 liters for the woofer.
Complying with my laziness (even if I try to ennoble it by telling
myself that it is Latin otium) and the desire to use as few resources as
possible, the joints are simple and I have eliminated the routing for
the woofer. This did not produce any bad tweeter diffraction. The cuts
for each box entered a sheet of plywood with a waste of less than 10%.
And only one hour of cutting machines in operation. From my point of
view, attention to our planet ...
Once the work was finished, the speakers entered my small listening
room.
First impact: exciting. The virtues of medium-high efficiency speakers
combined with a simple load I already knew and I found them intact. But
the quality and quantity of low frequencies and the great detail excited
me.
Days and days go by of running in and listening. I put the 1 Ohm
resistor to the tweeter, better.
But in the long run there remained a feeling of too much energy in the
mid-high and high range (3,000-5,000 Hz).
I resist and go on listening. Nothing, I begin to feel a little
discouraged. Strings often strung, strident harpsichord, drum cymbals
too forward and aggressive. In my room a similar result was given by a
pair of Yamaha NS-10s, very (too much) mixing monitors, with mid-high
range forward. It's been a month now and I start to regret the balance
of my Funspeakers and the pleasantness of their sound.
Action: I take my limited measuring tool, a Umik-1 mini dsp microphone,
and open RAW.
Measuring distance 50 cm, at midrange height, both on axis and at 10
degrees. As you know, this instrument does not simulate an anechoic
measurement, so in addition to direct radiation I also measure part of
the energy present in the room.
Although the room has good acoustic treatment, the measurements say that
in my small room there is an excess of 2,500 to 4,000 Hz. I imagine that
in better (larger) rooms, with other setups or perhaps with another
listening culture, the speaker is perfect.
I start to study the crossover better. I analyze the effect of the 68
Ohm resistor in parallel to the midrange 1mH inductor (it has to stay
there, its linearization is simple and effective), I measure the
midrange and tweeter responses separately.
I decide to try a small simple variation on the 8,2uF capacitor present
in the low pass of the midrange. I try and measure 10 and 12uF.
Wow! In my case, with 12uF, I get better linearity in the measures and
total naturalness when listening. The aggressive and too forward image,
also due to the proximity of the listening point, has disappeared,
leaving room for a nice depth and a big soundstage. The height of the
previously flatter scene has also improved. Finally, here is the
excellent speaker I was expecting! I rediscover the naturalness that I
had perceived with the Seas 3WC, a project of yours that I had listened
to in my room. But with a feeling of greater detail, speed and physical
impact.
Maybe I could add a little bit of energy from 3,500Hz upwards again. I
try to reduce the resistance of the tweeter from 1 to 1/2 Ohm, very
little stuff, but the result is perfect, more air and speed.
I'm aware that I've opened the crossing between midrange e tweeter,
modifying in a small part not only the frequency response, but also
impedance modulus and phase.
I consider this simple modification a small sartorial adjustment to
better adapt the speakers to my room, my setup, my tastes. I hope that
for you it does not represent an upheaval or a betrayal!
I just know that now I spend hours of pure enjoyment listening to these
speakers that I consider a masterpiece, sweetness combined with speed
and impact. A poor man like me now has his dream speakers to enjoy the
days left to him. Thank you with all my heart!
With regard
Giacinto
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