Yamaha NS1000M - Tweaks

[Qwin]

I didn't take this picture, but it's of the Scanspeak 30W/4558T00 12" Subwoofer.
It's featured in my sketch and I think it would make a good replacement for the Yamaha 12" Woofer and add some missing depth to the bass.
It's a fairly substantial driver as can be seen.




I think, because it has a low Fs of 17Hz, a reasonably large XMax and power handling, Scanspeak decided to place it in the Subwoofer category, it certainly gets used a lot for that application. But DIY builders including Troels Gravesen have used it as a straight Woofer in a three way. Below is Scanspeaks own frequency sweep for this driver.

Edit: It's worth pointing out this would be best implemented in an active set up, as this driver is 4ohm and also 4dB less sensitive than the 8ohm mid dome.




Don't be too alarmed by the peaks and troughs in the lower section, Scanspeak plots always look like this. Where most manufacturers use smoothing on the plot, or include nearfield response at the lower end, to make it look better, Scanspeak prefer to give you the true results warts and all, they have to be applauded for doing so.

The thing that struck me about this plot, was how flat it is in the upper bass and how far it extends up the range, definitely a response more like a Woofer than a true Sub, with its typical hump back curve.

This driver has an Efficiency Bandwidth Product (EBP) of 49 making it best suited for a sealed enclosure.

Taking the standard Qtc figure for a flat response of 0.707 this computes as an F3 of 38Hz in an ideal 55L (Net) sealed box.

So, by keeping the same footprint for the cabinet, it would only be around 100mm taller than the 50L NS-1000M. It would probably perform well, if not ideal, in the Yamaha cabinet. Sealed cabinet pairings are less fussy about exact volumes, compared with tuned ported cabinets.

It certainly ticks a lot of boxes for the Yamaha's, so not surprisingly, the spec grabbed my attention when I was checking out drivers for my other project.