SB65WBAC25-4
As the pictures above suggest this is a very well built driver with excellent attention to detail.
The basket is open in all the right places giving good air flow behind the spider/around the voice coil and behind the cone. SB also chose to add in voice coil ventilation via perforations in the coil itself. This accomplishes what a pole vent normally does but should not suffer from the resonance issues that they can sometimes present with. Indeed to help suppress any issues with resonances SB have also placed a felt plug on top of the pole piece and you can just about see this in the above image. Adding to the nice touches is a foam gasket on the rear of the mounting flange. For the price, indeed at any price, there isn't anything here to complain about.
The basket is open in all the right places giving good air flow behind the spider/around the voice coil and behind the cone. SB also chose to add in voice coil ventilation via perforations in the coil itself. This accomplishes what a pole vent normally does but should not suffer from the resonance issues that they can sometimes present with. Indeed to help suppress any issues with resonances SB have also placed a felt plug on top of the pole piece and you can just about see this in the above image. Adding to the nice touches is a foam gasket on the rear of the mounting flange. For the price, indeed at any price, there isn't anything here to complain about.
The drivers far field frequency response in the SBBT cabinet.
No surprises here really. A rising response towards the treble followed by the main cone breakup. A depression centred around 1kHz and some diffraction related stuff around 6.5kHz. Most of this follows SBs datasheet, which is always nice to see.
No surprises here really. A rising response towards the treble followed by the main cone breakup. A depression centred around 1kHz and some diffraction related stuff around 6.5kHz. Most of this follows SBs datasheet, which is always nice to see.
A near field shot in the same enclosure shoing the high Q alignment with the driver in the small box.
Here we can see the drivers distortion when driven with 2.83 VRMS.
This is a very low distortion driver and given its aluminium cone, shows absolutely no trace of distortion amplification from the cones resonance. This is most likely due to the ribbed nature of SBs cone but it's definitely effective! Many have tried all sorts of cone treatments in combination with metal coned drivers but with relatively little success. Where others have failed...
This is a very low distortion driver and given its aluminium cone, shows absolutely no trace of distortion amplification from the cones resonance. This is most likely due to the ribbed nature of SBs cone but it's definitely effective! Many have tried all sorts of cone treatments in combination with metal coned drivers but with relatively little success. Where others have failed...
The first of the above two graphs shows the drivers performance at 10dB below 2.83 VRMS and the latter shows 10dB above. As we can see the driver performs exceptionally well. These are exceptionally low levels of distortion. Given the drivers low price there is absolutely nothing to complain about and just too many projects that one could potentially include them in!