Test Bench: Wavecor TW030TU03 30mm Graphene-Coated Soft Dome Tweeter

This latest Wavecor soft dome tweeter is specifically intended for car audio applications. Voice Coil has featured several of Wavecor’s 30mm tweeters over the past several years including the TW030WA08 (December 2009), the non-cavity low-resonance version TW030WA09 (August 2012), the TW030WA12 30mm waveguide version (January 2015), the TW030WA13/14 (April 2015), and last, the TW030WA23/24 in the October 2023 issue. This month Wavecor sent the TW030TU03, its latest 30mm incarnation.
  Like the TW030WA13/14 and the TW030WA23/24, the new TW030TU03 includes a 30mm wide surround with a precision-coated graphene-reinforced cloth diaphragm optimized for high-frequency cutoff above 20kHz, internal chambers below the dome and surround edge, dual neodymium magnets vented into a damped rear chamber, copper-clad aluminum voice coil winding with a vented voice coil former, flexible lead wires for large excursions with crossovers below 3kHz (2kHz to 20kHz range), 92.5dB sensitivity, black machined and anodized aluminum housing for advanced cooling, a copper-clad pole piece (shorting ring), minimal mounting area for car audio applications, and 200mm leads for connecting to car audio amplifier wiring (see Photo 1 and Photo 2).
   Testing commenced using the LinearX LMS analyzer to produce the 300-point impedance sweep for the TW030TU03 4Ω version illustrated in Figure 1 (an 8Ω is not available). The resonance for the TW030TU03 occurs at a moderately low 716.5Hz. Factory quoted Qts for the TW030TU03 high-frequency transducer is 1.03. The measured DCR for the TW030TU03 was 3.4Ω with a minimum impedance above resonance of 3.65Ω at 2.95kHz.
  Next, I recess mounted the Wavecor graphene-coated dome tweeter in an enclosure that had a baffle area of 11”×7” and measured the horizontal on- and off-axis at 2.0V/0.5m (normalized to 2.83V/1m) from 0° on-axis to 45° off-axis using the Loudsoft FINE R+D analyzer and GRAS 46BE microphone (supplied courtesy of Loudsoft and GRAS Sound & Vibration).

Figure 2 shows the on-axis response for the TW030TU03, which exhibited a ±3.45dB response from 2kHz to 20kHz with the response out to 31kHz. Figure 3 depicts the on- and off-axis response of TW030TU03, with the off-axis curves normalized to the on-axis response shown in Figure 4. Figure 5 shows the 180° horizontal polar plot (in 10° increments with 1/3 octave smoothing applied), generated by the CLIO Pocket analyzer and accompanying microphone (courtesy of Audiomatica SRL).
 
Last, Figure 6 gives the two-sample SPL comparison showing the two Wavecor TW030TU03 samples to be closely matched within ≤1dB throughout the drivers’ operating range to 30kHz.
  For the next test procedure, I again used the Listen SoundCheck software and AudioConnect analyzer and SCM ¼” microphone to measure the impulse response with the tweeter recess mounted on the test baffle. Importing this data into the Listen SoundMap software produced the cumulative spectral decay (CSD) waterfall plot given in Figure 7. Figure 8 depicts the Short Time Fourier Transform (STFT) displayed as a color-variegated surface plot.
 
For the final test procedure, I set the 1m SPL to 94dB (3.48V for the TW030TU03) using a pink noise stimulus and measured the second and third harmonic distortion at 10cm, depicted in Figure 9.
  As with the entire series of 30mm tweeters, Wavecor has fielded another nice high-end product, this time intended for the car audio market. While this tweeter is intended for car audio applications, I think it would also be applicable for other applications where a minimal footprint is required. For more information about the TW030TU03 graphene-coated soft dome 30mm tweeter and other Wavecor drivers, visit www.wavecor.com.

This article was originally published in Voice Coil, April 2025