TAD TD-4003 on ES-450 Biradial No.2184

TAD TD-4003 on ES-450 Biradial No.2184

In this blog post I test the TAD TD-4003 on ES-450 Biradial No.2184. Horn model No.2184 is specially designed for the TD-4003 which uses a 39mm diameter throat. The ES-450 biradial normally has a 50mm diameter throat which is model No.2183 for reference. 

In this blog post I will conduct a full set of test data including some brief listening impressions. 

TAD TD-4003 Features

  • 10 cm diameter pure beryllium diaphragm
    • vacuum evaporation technology
  • 39mm throat diameter for wider off-axis coverage in the treble 
  • Neodymium magnet
  • 16ohm voice coil 
  • 600 Hz to 20 kHz
  • 112dB sensitivity (2.83v) (I measured +1 dB higher than this) 
  • Straight slit phase plug (see below)

Impedance Sweep 

The impedance sweep shows the FS centered at 376Hz with no breakup until around 18kHz.

Frequency Response

I measured the frequency response at 1m with a 3.2ms gate. I spiced the ungated response in at 1kHz using a 1/3 octave smoothing below 1kHz. Above 1kHz is 1/24 smoothing. The driver measures 110dB sensitivity at 1w/2v. 


Showing the same data but with the graph extended out to 50kHz is shown below.

This is one of the smoothest frequency responses I've measured. We see linear behavior across its bandwidth until 18kHz.

Horizontal Off-axis Behavior 

I measured the response at 5 degree increments to produce the following graphs. 

Below is the settings used in ARTA for the maps. As you can see, I've used 1/12 smoothing in order not to embellish the results. This is the most revealing setting within ARTA.

Time Domain


I measured harmonic distortion at 85dB and 95dB SPL at 1m. I inserted a 3.3uF capacitor to protect the driver. The microphone was placed at the horn mouth. 

Intermodulation Distortion 

I then tested IMD at the same 85dB and 95dB test signal levels. 

Measuring Gedlee Distortion Gm is shown below for the 85dB test signal level. 




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