Cat in the Hat

Let's see what's happening in the midrange.

First, the usual 300, 700 and 1100 Hz three tone tests.

Boy, it's hard to interpret the above. With the exception of the XG18, they all do quite well. There is no dominant clear winner. The SS and Usher just have a slightly noisier spectrum, interestingly. The Peerless is my pick for overall winner, actually based on overall performance, price, personal bias. The even order products are much better for the Peerless in the midrange.

But I wouldn't argue if you picked the Seas, Usher, SS, or RS. Just not the XG18.

Alright, let's look at 700 Hz.

Well,  the Usher is the winner. It's a closer spread between the others. The SS has second and third order distortion numbers as good or better than the Usher, but it's spectrum is a bit noisy. The Peerless is ahead of the RS, marginally, and tightly clustered with the Seas. Again, all are very good to excellent, but I think I can put the Usher on top in this one.

Alright, 1100 Hz.

Well, again, the Usher is on top. The SS and Peerless are probably next. The Seas and RS, being metal cones, are starting to get some distortion products amplified by cone breakup, but it's still very small, and really, these are all again tightly grouped/close. The XG18 is starting to improve...

One more set of tests.

Jon Risch sent me his AES paper a while back. You can find the link at http://www.geocities.com/jonrisch/PhiSpectral1.htm

So, I decided to try this sort of test signal on the drivers. Basically there are two sets of 4 tones, one set between 100 and 200, and another between 1000 and 2000 Hz.

Above, you can see the Peerless is cleaner than the RS180. Now, it's a bit of an unfair test to the metal coned drivers, which are getting extra distortion from the cone breakup. See the extra Seas graphs below.

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As you can see, a fair chunk of distortion between 3k and 6k that isn't present in the Peerless.

So, let's drop the last 2k stimulus. A 7 tone stimulus results.

The 3-5k distortion improves quite a bit. Now I don't have a corresponding 7 tone for the Peerless. But you get the idea. Moral-don't cross the W18 series or RS180 at 2k or above to minimize distortion.

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Both the SS and Usher are excellent, with the Usher being on top, the SS and Peerless in the next group. The metal cones are at a disadvantage in this test. If you're crossing them at or below 1.8k, these results probably don't apply. If you're crossing your metal cone w18 or rs180 at 2k or above, maybe you should rethink that...

And, of course, the XG18...respectable, though not class leading.

Conclusion

Despite all the graphs, I don't think the nonlinear distortion ranking has changed

1. SS 18W4531 and Usher 8945P

3. RS180,  Peerless HDS exclusive, W18EX, W18E

7. XG18

The Seas performed better than my original tests of the W18. Depending on your specific needs, any in the third rank is good. The revelator and the Usher are clearly in the top group overall, considering low end performance. As a dedicated midrange, the ranking is less clear. The Peerless probably becomes the price/performance leader for a midrange driver. The RS180 is a bit noisy unless crossed very low. (Hey, I think that there is a lot to be said for using a 7" as a mid, but that's another story.)

One issue I did not address is linear distortion. Go over to Zaph's site and look at the FR curves. The Usher is somewhat blemished by a pronounced dip in the 1-2k range. Many drivers have this, but it's a bit worse, or so it appears, in the Usher. The SS would be easier to work with in the crossover region based on Zaph's measurements. If it wasn't there, I'd say it would be the high end price/performance leader.  Is it worth paying an extra $200 a pair for a smaller midrange FR dip? Hmmm.

Blanket summary

RS180. Budget leader. Excellent low frequency even order distortion performance at any price and respectable odd order numbers.

Peerless HDS exclusive midrange price/performance leader. Has a bit of that 1-2k dip, otherwise, it might be crowned the midrange ultimate king. Those Peerless engineers must have engineered the dip back in so as to not steal the limelight from the revelators...;)

SS 4531G rev high end cost no object winner as used in a stand alone 2 way.

Usher 8945P high end price performance leader

I'm not meaning to marginalize the Excels. Actually, they did better than when I originally looked at them. But, they are not the leader at the low end, and they can't really pull away from the HDS in the midrange. Plus, they have to be crossed lower and steeper as you can see from the multitone tests as above.

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