Satori MW13P-4 measurements.

[5th element]

Time for some loudspeaker porn.

I bought a pair of these Satori drivers to have a little fun with. Here in the UK Falcon Acoustics has very good deals on most SB Acoustics drivers and has sales on them too from time to time. Unfortunately these were not on sale at my time of purchase, but compared to the average price across Europe Falcon is quite a bit less expensive anyway.

First up a picture of the front of the little guys. Some dust is still on the frame and dustcap so ignore that as I'd been working on the cabinets to put them in.



Next up a couple of rear shots...





These are very well built drivers. Incredibly solid with a very open rear to the cone. Pole and voice coil venting is provided via perforations in the voice coil former itself. Most drivers only use one of these methods for controlling under dust cap pressure changes but both end up creating a driver that is virtually free from any chuffing, even at high excursions. One thing that isn't readily apparent from screen shots is the rubber 'boot' that these have on the motor structure. As you can see the main struts on the basket are actually separate from the continuation that is present on the motor. The continuation isn't made from cast metal but is made of soft rubber. This is a nice touch as it not only looks good but will help to dampen any vibrations or resonances that could otherwise occur.

Now here is a picture where I have bastardised the Satori :E

Some will probably think I am mad but here is the driver with the dustcap removed.



As you can see, and as I would have expected from some of the cutaways I've seen of the series, there is a heavy copper ring/cap on top of the pole piece. Certainly these are going to be responsible for the excellent distortion performance that the series is known for, but the shape of the copper here also appears quite similar to the SD motor and balanced driver motor that scanspeak and wavcore use respectfully. As far as I am aware SB use copper below the gap to further increase linearity too.

Finally here is an image of the test box and box they will actually be used within.



These were an old set of boxes that I had used W15CY001s in as a midrange driver previously. So I whacked a new front on and recycled them. Here is where the very open basket really helps. As we've seen from other narrow cabinet designs compromised airflow around the back of the driver can add impedance wiggles/bobbles and FR shelves.

[5th element]

P.S does anyone know why the image attachments towards the bottom of the post are full size? This is rather odd.

Next up though is some actual data.

First up the frequency response.



This is a gated response taken at about 1 meter away in the cabinet illustrated above. As a result bafflestep and diffraction effects are present. Either way the response is workable. Nice and smooth up to about 5kHz where breakup really kicks in. Certainly this drivers cone has not been optimised anywhere near as well as the 6" versions has, but that is likely to be of little concern to those designing with it. The dip at around 1.6kHz is present but not to any severe degree.

Here is the distortion performance at 1vrms, 2.8vrms and then 5.9vrms.







First of all ignore the huge spike in distortion in the 5.9vrms test where the cone goes through breakup, this was due to the system clipping.

As can be seen the Satori is ridiculously linear and its performance is only marred by the presence of the high second order peaks due to that pesky resonance. Otherwise there is nothing to complain about and a 2nd order peak isn't going to be particularly objectionable anyway. The third order is class leading indeed. If SB ever decide to make an aluminium coned version of the Satori with their notched cone for a higher frequency breakup you'd have one of the lowest distortion drivers around as that second order peak would be completely absent. It reminds me of the SEAS magnesium vs nextel drivers as the nextel exhibit a similar 2nd order issue too that the magnesium do not.

Note also that in a larger cabinet the driver would show lower overall bass distortion too as these only have about 1.5-1.7litres to work in.

Finally here is an impedance plot magnified to show any midrange anomalies and as can be seen, even in the small constricted cabinet there is very little to speak of. The only thing that really shows up is the expected glitch around the cone edge/surround resonance.

[Jonasz]

Good work! :P Always nice to see some new driver testing, these threads are sadly few and far in between nowadays.