You make me look again at SB Acoustic website because I didn't know this unit. I see indeed they sliptted the 12" units in two class , the woofers and the subwoofers. I do not know what is the upper cut-off limits of their sub though ? 100 hz ? The Mms is indeed very heavy for the SW marked units.
If the SB34RNX-L has the edge with HD numbbers and motor as relative low weigth cone, perhaps for most in a 3 ways, just a sub is needed with 6.5 midwoofs units ? (cut off between 100 to 200 hz ?). After @profiguy input, I used that online spreadsheet and saw the 34NRX-l could have even lower sealed than 50L : around 40 L with a little boost.: F3 around 40 hz. that doesn't say the equilibrium is better at 40 L though.
| Enceinte close pour tous les usages, pour le SB ACOUSTICS SB34NRXL75-8 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Qtc | Vb | Fc | F3 | Ft = Fc / 1.32 | Formules de calcul | Clos pour graves F à -3 dB | Transformée de Linkwitz à Ft | Clos pour bas-médium filtre passif à Fc | Clos pour médium filtre > 4*Fc |
| L | Hz | Hz | Hz | Hz | Hz | Hz | Hz | ||
| 0.300 | 2231.3 | 22.3 | 67.8 | 16.9 | Vb = Vas/((0.300/Qtsb)2-1) Fc = 0.300*Fsb/Qtsb | 67.8 | 16.9 | 4*Fc=89 | |
| 0.350 | 421.7 | 26.0 | 65.5 | 19.7 | Vb = Vas/((0.350/Qtsb)2-1) Fc = 0.350*Fsb/Qtsb | 65.5 | 19.7 | 4*Fc=104 | |
| 0.400 | 217.8 | 29.8 | 63.0 | 22.6 | Vb = Vas/((0.400/Qtsb)2-1) Fc = 0.400*Fsb/Qtsb | 63.0 | 22.6 | 4*Fc=119 | |
| 0.450 | 140.7 | 33.5 | 60.3 | 25.4 | Vb = Vas/((0.450/Qtsb)2-1) Fc = 0.450*Fsb/Qtsb | 60.3 | 25.4 | 4*Fc=134 | |
| 0.500 | 100.8 | 37.2 | 57.8 | 28.2 | Vb = Vas/((0.500/Qtsb)2-1) Fc = 0.500*Fsb/Qtsb | 57.8 | 28.2 | 4*Fc=149 | |
| 0.541 | 80.4 | 40.3 | 56.0 | 30.5 | Vb = Vas/((0.541/Qtsb)2-1) Fc = 0.541*Fsb/Qtsb | 56.0 | 30.5 | Fc=40.3 | 4*Fc=161 |
| 0.577 | 67.5 | 42.9 | 54.7 | 32.5 | Vb = Vas/((0.577/Qtsb)2-1) Fc = 0.577*Fsb/Qtsb | 54.7 | 32.5 | 4*Fc=172 | |
| 0.618 | 56.4 | 46.0 | 53.6 | 34.8 | Vb = Vas/((0.618/Qtsb)2-1) Fc = 0.618*Fsb/Qtsb | 53.6 | 34.8 | Fc=46.0 | 4*Fc=184 |
| 0.707 | 40.5 | 52.6 | 52.6 | 39.9 | Vb = Vas/((0.707/Qtsb)2-1) Fc = 0.707*Fsb/Qtsb | 52.6 | 39.9 |
Last edited:
50 to 60 ltrs sealed is the sweet spot for the NRXL. You're at roughly critically dampened mode, which is ideal for EQ assist sealed. Any bigger and you waste excursion, any smaller you start impacting transient response, plus excessive power input to reach lower cutoff. You can go smaller than 50 and aperiodically dampen it, but it trades off lowest F3 capability and increases HD exponentially with excursion limits reached early.
If you had the money for 2 drivers per side, a total of 80 ltrs net with magnets back to back would work great. I prefer this arrangement for narrow baffled 3 ways with low xover points to mids. This requires a larger midbass or even a 4 way. Id use a 6 - 7 inch midbass and WG tweeter to push down the tweeter cutoff. This arrangement improves power response, while the narrow baffle helps with imaging and improved depth, given your baffle step and xover is optimized.
If you had the money for 2 drivers per side, a total of 80 ltrs net with magnets back to back would work great. I prefer this arrangement for narrow baffled 3 ways with low xover points to mids. This requires a larger midbass or even a 4 way. Id use a 6 - 7 inch midbass and WG tweeter to push down the tweeter cutoff. This arrangement improves power response, while the narrow baffle helps with imaging and improved depth, given your baffle step and xover is optimized.
You'll likely only notice the difference in character between all versions of the SB34 above 100 - 120 hz. The only exception is power handling and max output, but under realistic circumstances it won't be so noticeable, especially factoring in the room modes.
In a fullrange step response you see driver behaviour wide outside of it's used bandwidth! So put your filter in front and have a look what it is doing in your application.