18 Sound XT1086 with Radian 450PB

Fig 1 – 18Sound XT1086 with Radian 450PB RAW Frequency Response.

The Radian 450PB is my favorite compression driver. I am excited that it matches fairly well with the 18 Sound XT1086. The response is not as pretty as the previous Peerless DFM2535 but it’s totally acceptable for me. What I gain is the sound quality of this Radian and a lower crossover of 1.8kHz.

Fig 2 – 18Sound XT1086 with Radian 450PB Impedance

It appears that I will need to use a conjugate network (Fig 2). The 2nd, smaller peak is right where my crossover is at. I probably do not need to flatten the larger peak for it’s far enough from 1.8kHz.

Fig 3 – Spectrogram of 18Sound XT1086 with Radian 450PB

The Wavelet in Fig 3 shows minimal artifacts. It recorded very minor ones at 4kHz and 9kHz. They don’t last long to affect the sound, less than 1 msec.

Fig 4 – Waterfall of 18Sound XT1086 with Radian 450PB

The Waterfall plot in Fig 4 is a 3D view of the Wavelet. The artifacts at 4kHz and 8kHz ~ 9kHz are seen.

Fig 5 – ToneBurst Energy Storage of 18Sound XT1086 with Radian 450PB

Comparing the Toneburst plot (Fig 5) to that of the Peerless DFM2535, the Radian 450PB shows some excess energy from 7kHz~13kHz. This is inaudible as they don’t last more than 4 cycles. One cycle of 10kHz is 100usec. 4 cycles is 400usec. That converts to 0.4msec. This correlates to the Wavelet in Fig 3.

Fig 6 – Harmonic Distortion of 18Sound XT1086 with Radian 450PB

The Harmonic Distortion shows no anomaly. 2nd Harmonic is a low of 0.184%. 3rd is at 0.211%. 2nd to 9th is at 1.85%

Summary

I have no problems using this Radian 450PB with the XT1086. On paper, the Peerless DFM2535 is better but it’s really academic. No humans can hear anything at 0.4msec.

What is more important is the power handling. The Radian compression drivers are designed for the pro industry and as such, they can withstand tougher demands. I am confident I can cross it at 1.8kHz with the XT1086.

The icing on the cake is the sound of these Radian compression drivers. They are exceptionally “sweet”. Close to the venerable JBL2440. The other driver I have that shares the same sonic signature is the Emilar EC-175.

Unless otherwise stated, all measurements were made in Full Space (4 pi) with the mic at 36 ins, tweeter axis. Impulse Window=5ms. No smoothing applied.