Celestion TF1225 with Eminence PSD2002 + SST1

Celestion TF1225 with Eminence PSD2002 + SST1 horn
Active Bi-amped

Having tested out the TF1225 with the Pioneer PD-40 horn, it is time to design a 2-way for PA. Base on sound quality, my woofer of choice is the TF1225. If more power is required, I can always redesign it with a Dayton PA310 or the Peerless FSL 1225R02-08.

The horn combo section is the Eminence PSD2002 with the SST1 horn. I opted for this horn because of it’s constant directivity properties. This will be an advantage when the speaker is used in a church or outdoors. The PSD2002 compression driver is noted for it’s robustness in pro use. I am quite confident it will tolerate being crossed at 1.6kHz.

Fig 1 – Blue plot=Celestion TF1225 Low Pass  |  Red plot=PSD2002+SST1 High Pass  |  Black plot=Summed

Fig 1 is the Celestion TF1225 (Blue plot) with the Eminence PSD2002 + SST1 (Red plot). The Black plot is the summed response. Electronic crossover is a Linkwitz-Riley 24dB/oct set at 1.6kHz with CDEQ activated. Frequencies below 500Hz includes reflections in my room. Disregard the notch at 125Hz. That’s caused by a floor bounce. 

Fig 2 – Null response

The Violet plot in Fig 2 is the null response when I reversed the phase of the PSD2002. I am surprised by this null because no delay is used. The sharpness and depth of the null indicate the TF1225 and the PSD2002+SST1 combo are almost time-aligned.

Fig 3 – Summed Response

Fig 3 is the summed response of the TF1225 with the PSD2002/SST1 combo. After listening to it with various genres of music, I found this is the best tonal balance. Just 1dB more on the PSD2002 and the speaker will sound bright. I will use this response when I design the passive crossover.

Sound Quality of Celestion TF1225 with PSD2002 + SST1

I have no regrets choosing the Celestion TF1225 with the Eminence PSD2002/SST1 combo. The sound quality is fantastic. It’s even up to Hi-Fi level. With it’s enormous headroom, this speaker is ideal for Home Theater and tube lovers as well. 

For home use, I would replace the SST1 horn with perhaps a FaitalPro STH100 but I’ll leave that for another project. Most important is for pro use, I have a speaker that is superior to those run of the mill PA 2-ways in the market. My next step is to design the passive crossover.

Unless otherwise stated, all measurements were made with the mic at 36 ins, tweeter axis. Impulse Window=5ms. No smoothing applied.
Celestion TF1225 mounted onto a 53 liters test box of 14-1/2″ width. Port Diameter=3″. Length=1-3/4″.