(Page 01)
Construction of Raal JKN 01 MTM
Speakers
Design by Mr. Aleksandar Radisavljevic
Constructed by : Jiri
NOTE: updated on 10_12_2011
Speakers has been change to MT from MTM setup .Top PHL driver 1220 has been disconnected the bottom driver has been replace with PHL1370 (16 Ohms)
This speaker project has been in progress for some time now close to 2 years in fact but finally
the
construction is going ahead.
Firstly a brief note how JKN 1 came to reality. The idea was to construct
a MTM design with a ribbon tweeter. The system is based on a active setup
using DEQX no passive crossovers. Sealed box enclosures was a must (MTM) crossing at
80HZ where my Whise acoustic profunders 624 (modified) Subs takes over
Tweeters
I was looking for a good Ribbon tweeter some time back and my choices were
Raven R1
Raven R2
Raven R3
Aurum Cantum
Raal 140 15D
I have tried some Ribbon drivers before but was looking for some which could be crossed around 2000 HZ the contenders were R2 and R3. R3 was too expensive and R2 was still in my mind.
I have talked to a guy from Czech Republic and he recommended trying the Raal 140 as it is good. I did check the Raal website see the (pictures) graphs and all was looking good crossing at 1600HZ "well" .I did take the plunge and ordered these drivers and now I'm happy that I did, as I'm really happy with it's performance
Raal Details
FEATURES:
- Special FLATFOIL® pure Aluminium ribbon
- Special SYMMLEAD® low inductance signal path
- Special EQUAFIELD® NdFeB magnetic structure
- Special “non-wave-guide” INOX front plate
- Exceptional vertical dispersion
- Super-fast settling time
- Flat frequency response
- Low nonlinear distortion
- High signal power handling
- Highest reliability
SPECIFICATIONS:
- Ribbon material: aluminium
- Ribbon dimensions: ( 140 x 15 x 0.004 ) mm
- Ribbon mass: 0.022 g
- Ribbon area: 21 cm sq.
- Gap induction ( mean value over gap width): 0.51 T
- Frequency response: 500 Hz ~ 100 kHz
- Sensitivity: 95 dB / 1 m / 2.83 V
- Impedance: 8 Ohm
- Program power handling: 200 W*
- *Recommended crossover: 4th order L-R @ 1600 Hz
SPL VS FREQ.& Horizontal Dispersion
SPL VS FREQ.& Vertical Dispersion
Impulse Response
Impedance
Harmonic Distortion
Spectral Decay
Here is a link for Australian distributor
MID/BASS Driver
For Mid/bass I have been recommended to use some of these companies
PHL
Accutons
AudioTechnology
In the end I decided to go for the PHL.
It is suppose
to be a good match with Raal 140 D15
I brought the PHL 1220 which I'm happy with, but the new 1360 are suppose
to be better drivers. I am thinking of replacing them in the near future.
Note that all the Mid/bass Phl's drivers have the same (dimensions) and
mounting configuration, so they are very easy to upgrade. I would also like to mention that
PHL 1340 have been recommended to me as well, particularly with MTM setup.
|
TYPICAL CHARACTERISTICS |
|
|
|
|
Rated impedance |
Z |
W |
8 |
|
Half space sensitivity (1W@1m) |
- |
dB SPL |
93 |
|
Usable freq. range |
- |
Hz |
50-4000 |
|
Power handling capacity (AES) |
- |
W |
100 |
|
Max Sound Pressure Level |
SPLmax |
dB SPL |
109 |
|
Min. impedance modulus |
Zmin |
W@Hz |
6.6 @ 360 |
|
Voice-coil inductance @ 1kHz |
Le1k |
mH |
0,64 |
|
Voice-coil inductance @ 10kHz |
Le10k |
mH |
0,23 |
|
BL product |
BL |
N/A |
8,30 |
|
Moving mass |
Mms |
kg |
0,012 |
|
THIELE-SMALL PARAMETERS: TYPICAL (QC LIMITS) |
|
|
|
|
Resonance frequency |
Fs |
Hz |
45(±6) |
|
DC Resistance |
Re |
W |
6.1(±0.6) |
|
Mechanical quality factor |
Qms |
1 |
3,1 |
|
Electrical quality factor |
Qes |
1 |
0,27 |
|
Total quality factor |
Qts |
1 |
0,25 |
|
Mechanical suspension compliance |
Cms |
10-6.m/N |
1000 |
|
Effective piston area |
Sd |
m2 |
0,0143 |
|
Equivalent Cas air load |
Vas |
m3 |
0,030 |
|
Max linear excursion |
Xmax |
±mm |
3,5 |
|
Linear displacement volume |
Vd |
10-3.m3 |
0,050 |
|
Reference efficiency |
h0 |
% |
1,0 |
|
Unity load volume |
Vas.Qts2 |
10-3.m3 |
1,8 |
|
ABSOLUTE MAXIMUM RATINGS |
|
|
|
|
Short term max. input voltage |
Vmax |
V |
60 |
|
Max.excursion before damage |
Xdam |
±mm |
8 |
|
Ambient operating temperature |
Ta |
°C |
-10 to +50 |
|
Storage temperature |
- |
°C |
-20 to +70 |
|
Environemental withstanding Q |
- |
- |
Outdoor + |
|
APPLICATION INFORMATION |
|
|
|
|
Air volume occupied by the driver |
- |
10-3.m3 0,5 |
|
|
Speaker net mass |
|
kg |
2,15 |
|
Recommended reflex box |
Vb/Fb |
Lts/Hz |
15 L / 45Hz |
Here is a link for Australian distributors
WA - Australia
QLD - AUSTRALIA
The next step was to find the right design (enclosures.) I did not want to just make a simple box.I was looking for something different. I have to mention that at the same time a friend of mine Mark was after some enclosures for his 3 way design using the same drivers etc. MT enclosure (Raal 140 15D and 1 off PHL 1220)and for his bass he decided to used Peerless. Mark has been contacting Alex from Raal for any ideas. As a matter of fact it turns out Alex is a designer himself and he sent us some of his designs that he has done in the past. We had a look at his designs and it was clear to us that Alex is the man for our projects. Mark had some of his ideas, and let Alex know what he would like. It took some time as it turned out to be a more complicated design than originally planed. I won't explain how Marks 300KG each speakers design came to life. I will concentrate on my MTM 110 KG bookshelf.
Brief summary of my MTM's
It is a sealed box design with 2 closed transmition lines for both mid/bass
drivers
Click here if you interested at close TL design
(Hi-Fi World April 2009)
The box is constructed from 2 separate Ply's (909 subdue 24mm external and 28 hardwood ply (armor 34f) for internal and bracing. Note that 909 Subdue ply is a specialy made ply used in boating, aero industries and especially used as a soundproof partions' around engines and so on. The 909 ply is basically 2 pieces of 12 mm ply and in the middle a 5 mm wave bar is pressed and glued.
The box is going to be 50 mm thick all around.
Here is the Drawing
Links: