Question about SDA SRS and subwoofer phase
msg
Posts: 10,020
Hey guys,
I'm reading up a little on the SDA SRS/CRS and Monitor speakers, just learning a bit about how they work, etc.
Something occurred to me the other day - with the way the sub-bass radiator works in speakers like this, since they're sealed and seem to operate under action from the 6.5" drivers, it seems to me that the subwoofer would be out of phase? What's the story here?
Are the SDA drivers isolated from the regular drivers in the enclosure or is that all free air back there?
I'm reading up a little on the SDA SRS/CRS and Monitor speakers, just learning a bit about how they work, etc.
Something occurred to me the other day - with the way the sub-bass radiator works in speakers like this, since they're sealed and seem to operate under action from the 6.5" drivers, it seems to me that the subwoofer would be out of phase? What's the story here?
Are the SDA drivers isolated from the regular drivers in the enclosure or is that all free air back there?
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Post edited by msg on
Comments
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SW operates out of phase with MW's. The MW's don't have the cone area to produce sound below about 50 Hz so they are efffectively "off" below that frequency. The SW sarts working below 50 Hz so even though it's out of phase per se, it's not out of phase acoustically since it has no competion.'65 427 Shelby Cobra
'72 Triumph TR-6
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The SDA drivers and the Stereo drivers do not have separate air chambers in the cabinet. On the later-generation SDA speakers, both the SDA and the Stereo drivers work together in the bass region to power the passive radiator.
I'm taking a guess that the passive radiator--or tuned vent, in a ported design--phase is variable depending on frequency. -
As with a ported box the passive radiator will be in phase with the midbass drivers for a limited bandwidth around it's tuning frequency.It becomes progressively more out of phase as frequency decreases.Thats why it has a steeper rolloff rate at low frequencies (approx.24db per octave) vs the shallower 12 db slope for a sealed box.
