Selenium D220Ti OMF

1" Titanium Compression Driver



Apr 20, 2013

Selenium D220Ti OMF with Pyle PH715

The D220Ti is a popular compression driver in the DIY community. The OMF is the 2/3 hole bolt version. According to the manufacturer's specs, it has an extended frequency bandwidth covering 1,000Hz-21,000Hz, making it an ideal candidate for Hi-Fi.

Fig 1 below is the Impedance Sweep of the D220Ti OMF with the Pyle PH715. The D220Ti resonance frequency (Fs) is about 680Hz.

Fig 1 - Impedance Sweep of D220Ti with Pyle PH715 horn

Frequency Sweep

The Black trace in Fig 2 is the response of the D220Ti/PH715 combo with the Synergy crossover at 1,000Hz.

It appears the combo can in fact be crossed as low as 1,200Hz. With the resonance peak at 680Hz, it is likely that a conjugate network would be necessary.

The Red trace is with the Synergy at 1,750Hz. At this frequency, there's no need for the conjugate network to damp the resonance. Power handling is obviously improved too.

Lastly, the Violet trace is with a 8.2uF capacitor inserted in series with the combo. This corrects the dipping response of the higher frequencies.

Fig 2 - D220Ti/PH715 Frequency Response


Selenium D220Ti / PH715 in use

There are two designs of the D220Ti with the PH715.

The Nightingale-III is a Bass Reflex using a Dayton RS-180s, a 7" mid-woofer.

The Nightingale-IV is a Closed Box design using HiVi"s M8a 8"mid-woofer.

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