Principe
Le logiciel BBOX! est un outil gratuit, il permet de synthétiser les filtres actifs, passifs et les enceintes acoustiques.
Les filtres passifs
-
- Passe-bas: 6db, 12db, 18db et 24db
- Passe-haut: 6db, 12db, 18db et 24db
- RC, RLC, Compensation d’impédance, etc.
Filtres R-C
Filtres R-L-C
Simulateur des filtres passifs
Filtres actifs
Enceintes
-
- Enceinte ventilée et fermée
- Passe-bande
- Dimensionnement du basshorn en forme: Conique, exponentiel ou hyperbolique
- Ligne de transmission
- URPS (Under Resonance Principle Subwoofer): Châssis de haut-parleur égalisé électroniquement dans un boîtier fermé
- Etc.
URPS
CHP/VHP
Formules
Calaulations on ventilated systems :
- fb = Sqr(fL^2 * fH^2 * fC^2) : fsb = (fL*fH) / fb
- Rm = Ro/Re
Attenuation of Chassis in db :
- X = 20 * LOG( Qts )
Systemresonance ( for closed Systeme ) :
- fc = SQR( VAS / VB + 1 ) * fs * 0.9
Level on Systemresonance :
- Spl(db) = 20 * LOG( Qtc ) ==> ( 0db = reference )
Efficiency ( % ) :
- no = ( PI^2 / c^3 ) * ( fs3 * VAS ) / Qes
Theor. Idealvolume :
- Vb/id = VAS / ( 0.707^2 / Qts^2 – 1 )
System Q :
- Qtc = Qts / SQR( VAS / VB + 1 )
Chassis Q
- QTS = QMS * QES
Lower -3db frequency :
- f3 = SQR( VAS / VB ) * fs
For optimal attenuation of resonator :
- Resonator-Minimumprofile = ‘Ar/min’ = (( 0.1 * ( Vb * fb ) ^.5 ) / 2 ) ^2 * PI
Theor. optimal Resonator-Tuningfrequency :
- fb = ( 0,42 * fs ) / ( Qts^0,9 )
Resonator :
- L = ((30000 * a) / (f ^ 2 * v)) – (Sqr(pi * a) / 2)
- a = ((Vb * f3) ^ 0.5 * 0.1) ^ 2 * 3.14 /
Akkustic Power » Pak » :
- Pak = ( 9,7 * 10^-7 * fs * VAS * Pel ) / Qes
Membrane movement » W » =
- W = ( .35 / r^2 * fs^2 ) * sqr(Pak)
Prime mover :
- Ka = B*L*I => drivefactor = B * L
Brake force:
- Kb = (( B * L )^2) * Re
Ripple :
- R = 20 * Log(2.6 * Qts * Y ^ 0.35)
Tunefaktor » h » :
- h = fb / fs
To avoid Partial oscillations :
- f/max = 344 / d
Wavelength of sound ( m ) :
- Lambda = 344 / f
- f3\Low = c / ( 2 * Roomlength )
Lowest frequency in relation to Membranediameter :
- Fg = c / ( d * 4 )
Qes/new = (( Re + Rsf ) / Re ) * Qes/old
- ==> Qts/new = ( Qms * Qes/new ) / ( Qms + Qes/new )
- ==> Qtc = Qts / SQR( VAS / VB + 1 )
Notations
- fs = Resonancefrequency Speakers ( Hz )
- VAS = ?quivalent Volume Speakers ( ltr )
- Qts = Q of Speakers
- Qes = elektric Q of Speakers
- Qms = mechanic Q of Speakers
- Qtc = System Q
- QL = Leck Q Box
- z = Speaker-Impedanz ( Ohm ) – compensated !
- Re = DC resistance Speakers ( Ohm )
- Le = coil inductance Speakers ( Millihenry )
- fc = System Resonancefrequency ( Hz )
- fb = Tuningfrequency of Resonator ( Hz )
- Vb = Nettovolumen der Box – 10% ( ltr )
- Spl = acoustic pressure ( db )
- Rsf = DC resistance /Filter ( Ohm )
- no = attenuation ( db )
- c = sound velocity ( c = 343 m/s bei 20?C\0m)
- f = Frequency ( Hz )
- d = Membrane diameter ( m )
- P = power( W )
- f3 = -3db frequency