The photograph on the left is a picture of the Am-Com ClearSpeech Speaker model CSS-1 .
This is a speaker that incorporates audio digital signal processing(DSP) and is designed to remove static, steady tone noise such as carriers, and other interference. The ClearSpeech Speaker is a digital speaker that removes up to 95% of the background noise from the receive side of any two-way radio communication for greater intelligibility of the incoming conversation. The speaker has an on off switch and requires a 12 volt power source. If you do a lot of HF work while mobile then this speaker may be just what the doctor ordered.
The photograph on the right is a picture of the Icom SP-20 speaker which is designed for use with a wide variety of communication equipment. The SP-20 is equipped with four separate audio network filters for maximum control of the audio characteristics of received signals. The SP-20 rear panel features two audio input jacks (3.5 mm mini jack). Input A or B may be selected from a switch on the front of the speaker. There is also a Speaker On/Off switch and a 1/4 inch headphone jack on the front panel.
The internal speaker Size is 5 inches(12 cm) and the rated input power is 3 watts. The impedance of the speaker is 8 ohms and the maximum rated power is 5 watts. It has a frequency response of 100Hz to 9000Hz. The filters on this item have the following cut-off frequencies,
* High Pass filter 1 300 Hz
* High pass filter 2 600 Hz
* Low pass filter 1 2400 Hz
* Low pass filter 2 800 Hz
The filter response is an impressive -6dB octave.