The bass-reflex enclosure differs from the closed chamber by the presence of one or more vents. The bass-reflex uses the principle of the Helmholtz resonator consists of an internal volume and a vent that opens to the outside, in its simplest form.
The principle of the bass-reflex is to recover the sound waves inside the load by the depression in the rear of the boomer (equivalent to the forward pressure) to return them in phase with sound waves issued frontally.
The bass-reflex name comes from the English reflect, the idea being to reflect the sound that is inside the box like a mirror that reflects the original image. It adjusts the agreement of the vent (to avoid important phase shifts) over a frequency region where the displacement of the membrane is kept, almost zero, the sound radiation is then relayed through the vent so as to best reduce the bass distortion in the vicinity of the resonance frequency.
The volume of the enclosure and the agreement of the vent (depth, diameter) are determined by the characteristics of the speaker. The work of Thiele & Small have identified a number of technical parameters used in calculating the loads of all types ... All speakers are indeed not suitable for bass-reflex. To clear roughly, we say that a speaker with a QTS between 0.25 and 0.45 works in Bass-reflex, but it is possible to use speakers with a QTS smaller than 0.25 if the VAS is high.
• Input impedance : 8 Ω
• Rated power : 100 W
• Maximum power : 150 W
• Sensitivity (for 1 W at 1 m) : 93 dB
• Rated frequency range : 50 to 20 000 Hz
• Cutoff frequency : 5000 Hz
- Tweeter : Piezo + acoustic lenses
- Boomer : 27 cm 3A - W150
Caractéristiques
Unités
Valeurs
Puissance nominale
W
150
Puissance maximale
W
200
Bande passante
Hz
25-2000
Niveau d'efficacité caractéristique
dB
93
Diamètre nominal hors tout
mm
295
Diamètre bobine mobile
mm
38
Diamètre ouverture baffle
mm
234
Introduction dans l'entrefer
gauss
14 200
Flux dans l'entrefer
Maxwells
102 000
Énergie magnétique du moteur
WS-1
0,620
Facteur de force
NA-1
11,87
Hauteur du bobinage
mm
14
Hauteur de l'entrefer
mm
6
Masse de l'aimant
g
850
Masse équipage mobile
g
18
Masse du haut parleur
g
2 800
Impédance nominale
Ω
8
Fréquence de résonance
Hz
40
Facteur de qualité mécanique
Qms
3,43
Facteur de qualité électrique
Qes
1,77
Facteur de qualité total
Qts
0,42
Compliance de la suspension
10-3 MN-1
-
Température max de bobine mobile
C
180
• Dimensions (H x W x D) : 65 x 38 x 31 cm
• Unit weight : ?
The « Pro » series has been studied for mobile discos and musical instrument amplification.