18 Sound XT1086 with Eminence PSD2002


where robustness takes priority

For users that demand their compression drivers to withstand hard use, there’s no other better than the Eminence PSD2002. This driver is a brute. It has a power rating of 80W (AES) and is stipulated to be able to cross at 1.2kHz (12dB). It is so rugged and affordable that hidden inside many pro loudspeakers are these PSD2002. My Community XLT46, a 15″ 3-way, uses this PSD2002 for the highs. It was re-labeled as a Community HFE2 but I’m certain it’s the same driver.

Fig 1 – 18Sound XT1086 with Eminence PSD2002 RAW Frequency Response.

The response in Fig 1 is of the PSD2002 bolted onto the XT1086. No crossover is used for this measurement. Microphone was at 2FT, horn axis and no smoothing applied.

The first thing that struck me are the two peaks, one at about 3kHz and the other at 9kHz. Furthermore, there is a light notch at 5.5kHz. This does not look flat at all but in the pro world, the peak at 3kHz can easily be equalized flat by use of EQs. What is interesting is it appears no CDEQ is necessary. All one has to do is to flatten the 3kHz peak and the working bandwidth from 1.5kHz ~ 10kHz is flat. In olther words, you get constant directivity without sacrificing sensitivity. This has significant implications for passive crossovers.

The downside of using this PSD2002 is the highs falls off the cliff at 10kHz. For users that insist the bandwidth extends all the way to 15kHz, there is an abundance of super tweeters available today that can easily be added. My favorites are the JBL2404 followed by the Peavey HT94.

Fig 2 – 18Sound XT1086 with Eminence PSD2002 Impedance

The Impedance of this combo is shown in Fig 2. The peak at 1750Hz must be tamed otherwise the crossover will be affected. The one at 500Hz can be left as it is. The lowest impedance is at 8Ω. This confirms that my PSD2002 is indeed an 8Ω version.

Fig 3 – Spectrogram of 18Sound XT1086 with Eminence PSD2002

The Wavelet in Fig 3 shows artifacts at 5kHz and some at 10kHz. They dissipate by 1msec, so nothing to worry about.

Fig 4 – Waterfall of 18Sound XT1086 with Eminence PSD2002

The Waterfall plot in Fig 4 is a 3D view of the artifacts at 5.5kHz and 10kHz. They don’t last long, about 1msec only. 

Fig 5 – ToneBurst Energy Storage of 18Sound XT1086 with Eminence PSD2002

The Toneburst plot in Fig 5 shows excess energy at 5.5kHz and 10kHz. Looking at the RAW response in Fig 1, the notch is exactly at 5.5kHz. So what we’re seeing is diffraction caused by cancellation at this frequency. I won’t lose sleep over this as they are inaudible.

Fig 6 –  Harmonic Distortion of 18Sound XT1086 with Eminence PSD2002

The Harmonic Distortion shows no anomaly. 2nd Harmonic is at 0.518%. 3rd is at a low of 0.187%. 2nd to 9th is at 1.77%. Generally, the distortion is about 50dB~55dB below the fundamental. 

Summary

I am pleased to find that this Eminence PSD2002 can be used with the XT1086. This is an important discovery because there are plenty of PSD2002 in the market.

For users that are not satisfied with the sound of their horns, don’t waste money buying a new speaker. Simply replace the horn with the XT1086 and re-use the PSD2002 that came with the speakers. It will elevate their speakers to a whole new level.

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.