Building
the
DELTA 4R5 speaker system
(a.k.a.
Audiolab
DELTA 4.5)
(web
page under work)
Introduction
Here will be described my construction of the Audiolab Delta 4.5
speaker system.
The original project is by Renato Giussani a worldwide recognized
italian loudspeaker system designer.
Delta 4.5 is a top-level quality system with a
very original
and good looking
design. It is an up to date version of the Audiolab Delta 4, one
of the first Giussani's designs that still now, after more than 30
years, is considered a very good sounding product.
The picture below is a rendering done during the project phase.
The total budget to build this system is around 1100-1200
€.
This is only to cover parts and materials. I think that
a commercial version of this system will cost more
than 6000
€, but it sound is worth even a lot more than that!
I tried to follow the original project (no longer freely available) as close as possible.
Project
Speaker components
This is a 4-way speaker system.
These are the drivers used in the system.
Woofer
The woofer is the 4 ohm NHT 1259, a 12 inch made
by Foster now discontinued.
And these are manufacturer's specifications:
| NHT
1259
Specifications |
| Fs |
16.5Hz |
| Nominal Impedance |
4 ohm |
| Mmd |
128.0 Grams |
| Cms |
696.48 m/n |
| Vas |
238.4 Liters |
| Rscc |
3.52 W |
| Leap Krm |
3.277 mW |
| Leap Kxm |
10.063 mH |
| Leap Erm |
0.772 |
| Leap Exm |
0.743 |
| vcL |
1.06mH @1K |
| Bl |
9.574 Tm |
| Qms |
2.680 |
| Qes |
0.533 |
| Qts |
0.445 |
| Voice Coil Height |
34 mm |
| Air Gap Height |
8 mm |
| Xmax |
13.0 mm Peak |
| SD |
0.0491 m 3 |
| Surround |
Rubber |
| Cone Material |
Polypropylene |
| Magnet |
59 oz. |
| Voice Coil |
50 mm |
| Music Power |
300 Watts |
| Sensitivity |
90 dB 2.83V/1m |
| Price |
$150.00 |
Low-Mid (planar)
The low-mid is a planar component, the Bohlender Graebener's Neo8.
You can find it on Parts-Express
catalog code
264-712.
Here is the link to the datasheet.
High-Mid
It is a Scan-Speak: D3806/820000.
Tweeter
It is another Scan-Speak:
D2010/851300.
System enclosure
The cabinet is composed by a prism-shaped closed base for the
woofer and an
upper panel for the remaining 3 components. Two tall frames
covered with fabric hide all the inner parts giving the entire system a
monolithic look like an electrostatic system.
This is an exploded view from the original drawing of arch.
Massimo Massetti.
The Final Result
This is one of the completed speaker ...
Acoustical Measures
Here are some room measures.
The mic was positioned in the listening position 2.8 meters from the speaker and 110 cm from the ground.
The first one is pink noise response 1/3 octave. Single speaker (red right speaker, black left one).
The second picture is still pink noise 1/3 octave but both speaker together.
Note the expanded scale.
Last one is MLS reponse, right speaker only.
Project © 2004-2005 Renato Giussani;
This page © 2005-2006-2013 R. Lorello
Page last updated onTuesday, 01-Oct-2013 22:54:26 CEST
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