Zapco, founded over 30 years ago by Robert Zeff, was one of the original manufacturers of what we all now know to be "high-end" car audio. While Zeff has moved on, the heritage of Zapco remains true. This can be heard in their amazing amplifiers and electronics. But they have yet to tap into one key element of this industry: speakers. Thatis all changing. Zapco recently teamed up with its sister company, ESB, a high-end Italian speaker manufacturer (both brands are owned by parent company, Skyway Corp.). The result of this partnership is the CK-16.2 component set.
The components feature some interesting technology, including some even more interesting claims in the literature. The woofer for example is in a cast "parabolic" frame that is said to offer minimum air resistance behind the cone. To me it looks like an ordinary four-spoke basket-or to be more precise a cast basket that looks like a stamped basket. I don't understand why you'd tool an expensive basket to make it look like a cheap stamped basket. That aside, the woofer features a non-pressed paper cone with the rough side out. This makes an interesting cosmetic statement, and a very rigid cone-maybe too rigid, though. The edge is parabolic in shape with a very distinct peak. The literature says that this increases the cone area compared to a traditional speaker; however, I did some comparisons to other speakers I have around and found that the difference is insignificant or, in some cases, the Zapco is smaller.
The rest of the set consists of two crossovers and two very nice tweeters utilizing high-quality silk domes and neo magnets. Unfortunately, the mounting options are pretty limited, allowing them to only be flush mounted in panels that are thinner than 1/4". Otherwise, you'd have to do something very custom. The attractive crossovers use high-grade capacitors and coils. Two easily accessible switches allow you to reverse the tweeter phase and select between three levels of tweeter output. The crossovers are also bi-amp capable; however, there is no bypass for wiring 2-channel operation, so you need to make your own jumpers.
OK, so I am not too impressed by the cosmetics or feature set, but if it can perform, who cares? So on to the testing...
Parameter Testing
My testing starts with "Small Signal Parameters" for the woofer. If you have been following the reviews this year, you know that I actually measure "Small Signal" at a more realistic level than traditional tests. Small signal for the Klippel system can be measured as the highest voltage before the speaker starts to become nonlinear. For the Zapco woofer this was at 4.5 watts, which is a pretty good starting point for the operating range of the speaker. The key parameters are listed in the chart below.
So how do these stack up?
The efficiency of the woofer is pretty low. However, the larger voice coil (1.5") means higher power handling, so this isnit too bad. The low mass and low Qts mean that it will have pretty decent bass up to the limits of its excursion. The combination of low efficiency and low Fs and Qts are not my ideals though-especially considering the recent series of very high-efficiency component sets I have tested in this price range.
Klippel testing has giving us a way to look at the ability of a speaker to produce bass. The non-linear Motor Force (BL [X] and Compliance (Cms [X] are graphical representations of what the speaker is doing while it is playing. They reveal if everything is balanced and working together. Both of these curves should be centered on the X(mm) 0 line and have essentially the same shape on either side of this point. The dashed lines on the graphs are the mirrors of the actual test and make it easy to see if the curves match the ideal.
The Bl (X) (Graph 1) curve for the woofer shows a pretty awful response. The motor for the speaker is biased about 2mm, which means that it will be running out of room for travel at lower frequencies. This won't be critical if you are using these with a subwoofer however.
The Cms(x) (Graph 2) curve shows the same bias in the same direction. This typically means the suspension is forcing the coil out of position. However, in this case the spider is flat and in the correct position. It possible that the offset is caused by the unique edge shape or the progressive spider.The Bl (X) and Cms (X) curves can also be used to predict the maximum excursion for the speaker (Xmax). It is defined by Klippel as the point at which the compliance or Bl nonlinearities create 10% harmonic or intermodulation distortion. For Bl this happens when the Bl has dropped to 82% of its x=0 value (XBl) and Cms has dropped to 75% (Xc). For the Zapco woofer the XBl point is 3.3mm and the Xc point is 2.4mm. My guess is that if the suspension bias was corrected these numbers would be closer to 4.5mm.
So the question is, "How will this sound?" There is a lot of debate about this subject in the audio engineering community. How bad does distortion sound and what kinds of distortion sound the worst? Many engineers are starting to think that the kind of distortion that will be created by this type of problem canit be easily heard. In fact, in this case it may be virtually inaudible. There are suggestions for better tests that follow how we perceive sound quality, but for now there is no standard. Linear is still better, of course, and a perfectly centered coil and suspension is still our ultimate goal.