The Nightingale

By Lars Mytting
02 Nov 1996

ScanSpeak 2905/9900 Revelator

The Revelator uses no ferrofluid in the air gap, making the resonance peak higher and more narrow than oil-damped tweeters. It has a copper ring around the dome, which is claimed to eliminate the electrical phase shift and reduce distortion.

This baby differs from the other 2905 drivers in having a very large, concave frontplate. According to the manufacturer, the shape is intended to improve directivity. In the official data, it also measures more linear than the 2905/9700, which essentially is a 9900 with standard frontplate.

The Revelator really sounds well, with some margin better than other softdomes I have heard. Most of all I feel that it blends very well with the midrange of the system; it does not emphasise itself; and does the tough act of "not being there" very well. I find it lighter, more weightless than the regular 2905/9000, but with the same good dynamics. It has the same "accent" as the other 2905's; a somewhat dark, easy-floating quality. The driver also has adequate linearity and good power handling capacity. The driver employs a special coating which is applied by hand.

The first set I bought of the Revelator showed quite large differences in the frequency response between the two samples. Using the Clio system, I found that one driver had a +3dB peak at 15,000 Hz. Later, I got a new set that showed far better consistency, and the performance was now remarkably smooth, with a difference of only +1/-0.5 dB in the upper octave. There are no visual change between the "old" and the "new" tweeters, but the new drivers are packed and delivered in pairs, while the former series were delivered one by one.

The impedance peaks on the new drivers were located at 507 Hz at 23.0 ohm and 501 Hz at 26.4 ohm. The impedance peaks on the old drivers were located at 522 Hz with 27.6 ohm and at 537 Hz with 25.4 ohm.

Note that these graphs show the difference between the samples, not the frequency response itself Fig. 1. Old Revelator drivers Fig. 2. New Revelator drivers.

The large front plate looks impressive, and it has a heavy, expensive feeling; very special-purpose and authoritative. It also makes a rigid mounting for the driver. But the diameter (130 mm) forces a large distance to the midrange driver, making phase- related interference patterns a larger problem than with smaller front plates.

The bolts to the magnet system are flush-mounted, and so are the mounting holes to the cabinet. Other 2905-tweeters does not have flush-mounted bolts, and I will devote some frustration to this fact. I really cannot see why ScanSpeak restrict this feature to their top model. Nearly all other tweeter manufacturers, down to the cheapest Indonesian type, flushmounts all bolts.

Neither can I understand why ScanSpeak continue to use their small, Mickey Mouse-terminals. They are far to weak, and break off after a few times with experimenting and resoldering, especially with stiff cables. Yes, tweeter soldering is a delicate art, not macho welding, but take a look at Dynaudio's terminals: Compared to ScanSpeak, they seem intended for war. Of course, neither terminals or flush-mounted bolts affects sound quality much, but why settle for a low standard on some parts of atop quality product?

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