Features include a neodymium magnet motor structure, copper foil-clad pole shorting ring (Faraday shield) vented to a damped rear chamber, a compact injection-molded 70mm (2.6”) diameter faceplate and rear cavity, a 4Ω 22mm diameter voice coil with a vented aluminum former wound with copper-clad aluminum wire (CCAW), built-in cavities beneath the dome surround, a foam mounting gasket, and gold-plated terminals.
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Testing commenced using the LinearX LMS analyzer to produce the 300-point impedance sweep shown in Figure 1. The tweeter resonance occurs at a moderately low 670Hz. With a 3.13Ω DCR (Re), the minimum impedance for this tweeter is 3.5Ω at 3.2kHz.
Following the impedance test, I recess mounted the Wavecor tweeter in an enclosure with a baffle area of 12" × 5" and measured the on- and off-axis frequency response using the LoudSoft FINE R+D analyzer (provided by LoudSoft) and the GRAS 46BE 1/4” microphone (courtesy of GRAS Sound & Vibration). I set up the equipment to measure from 200Hz to 40kHz (using a 192kHz sampling rate) at 2V/0.5m normalized to 2.83V/1m. Sweeps were performed at 0°, 15°, 30° and 45°. Figure 2 shows the on-axis response, which measured ±2.5dB from 1kHz to 20kHz, with the response extending to 30kHz.
Figure 3 gives the TW022WA09’s on- and off-axis response. Figure 4 shows the off-axis curves normalized to the on-axis response. Figure 5 provides the CLIO 180° polar plot (measured in 10° increments with 1/3 octave smoothing). Figure 6 shows the two-sample SPL comparison of the Wavecor TW022WA09, indicating the two samples were closely matched to within 0.8dB throughout its operating range to 30kHz.
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For the final test group of tests, I initialized the Listen, Inc. SoundCheck analyzer along with the Listen SCM 2 1/4" microphone (provided courtesy of Listen, Inc.) and measured the impulse response with the tweeter recess mounted on the 12” × 5” test baffle. Importing this data into the Listen SoundMap software produced the cumulative spectral decay (CSD) waterfall plot shown in Figure 7. Figure 8 shows the Short Time Fourier Transform (STFT) displayed as a surface plot.
For the last SoundCheck test procedure, I set the 1m SPL to 94dB (3.87V) using a noise stimulus, and measured the second and third harmonic distortion at 10cm, depicted in Figure 9.
Wavecor’s build quality is typical of the high-end two-channel /home theater OEM driver market, and has remained consistently so for a number of years. The TW022WA09 is well configured and a good alternative to blend with 3.5" to 5.25" drivers in two-way applications, and as Wavecor suggests, it should be able to work in most applications intended for 1" domes. For more information, visit www.wavecor.com. VC
![](https://cdn.xingosoftware.com/audioxpress/images/fetch/dpr_1,w_765,h_497,c_fit/https%3A%2F%2Faudioxpress.com%2Fassets%2Fupload%2Fimages%2F1%2F20210412204051_Figure7-WavecorTW022WA09DomeTweeter.png)
![](https://cdn.xingosoftware.com/audioxpress/images/fetch/dpr_1,w_765,h_473,c_fit/https%3A%2F%2Faudioxpress.com%2Fassets%2Fupload%2Fimages%2F1%2F20210412204050_Figure8-WavecorTW022WA09DomeTweeter.png)
![](https://cdn.xingosoftware.com/audioxpress/images/fetch/dpr_1,w_765,h_823,c_fit/https%3A%2F%2Faudioxpress.com%2Fassets%2Fupload%2Fimages%2F1%2F20210412204050_Figure9-WavecorTW022WA09DomeTweeter.png)
This article was originally published in Voice Coil, January 2021.