Peavey SP 118X Description, Frequency Response, Architectural and Engineering Specifications

Description

The SP 118X 4 Ohm is an add-on subwoofer designed to make it easy to add more low end to the SP X Series or other full-range speaker systems. Other uses include bass guitar and drum monitoring.

The enclosure is constructed of 3/4" high density OSB and MDF, and covered with a heavy-duty black carpet and reinforced with polymer corners. A black metal grille covers the front of the enclosure. Recessed handles on either side provide portability.

This low frequency system consists of an 18" BWX Black Widow® woofer with Kevlar® impregnated cone, mounted in a vented enclosure along with a passive crossover. This design provides strong bass extension and high power handling to complement a full-range sound system.

The SP 118X 4 Ohm includes a passive subwoofer crossover, set at 125 Hz. This crossover supplies both a low-pass output to the 18" woofer in the enclosure, and a high-pass output to a 1/4" panel jack. For biamp / direct input use, a Neutrik® jack is also provided.

Frequency Response

This measurement is useful in determining how accurately a given unit reproduces an input signal. The frequency response of

the SP 118X 4 Ohm is measured at a distance of 1-meter using a 1 Watt (into the nominal impedance) swept-sine input signal. The solid line represents anechoic filtered response; the dotted line is anechoic direct input; and the dashed line shows typical room response through the filtered input. As shown in figure 1, the selected driver in the SP 118X 4 Ohm combines to give a smooth frequency response from 50 Hz - 128 Hz.

The impedance response in Figure 2 shows the impedance curve for filtered response as a solid line, and direct input as a dotted line.

Power Handling

There are many different approaches to power handling ratings. Peavey rates this loudspeaker system’s power handling using a full-range form of the AES Standard 2-1984. Using audio band 20 Hz to 20 kHz pink noise with peaks of four times the RMS level, this strenuous test signal assures the user that every portion of this system can withstand today’s high technology music. This rating is contingent upon having a minimum of 3 dB of amplifier headroom available.

Harmonic Distortion

Second and third harmonic distortions vs. frequency are plotted in figures 5 & 6 for two power levels, ten percent (10%) of rated input power and either one percent

(1%) of rated input power or one watt, whichever is greater. Distortion is read from the graph as the difference between the fundamental signal (frequency response) and the desired harmonic. As an example, a distortion curve that is down 40 dB from the fundamental is equivalent to 1% distortion.

Architectural and Engineering Specifications

The loudspeaker system shall have an operating bandwidth of 50 Hz - 128 Hz. The nominal output level shall be 98.0 dB when measured at a distance of one meter with an input of one Watt. The nominal impedance shall be 4.0 Ohms. The maximum continuous power handling shall be 500 Watts, maximum program power of 1,000 Watts and a peak power input of at least 2,000 Watts, with a minimum amplifier headroom of 3 dB. The outside dimensions shall be 32.50 inches high by 20.75 inches wide by 29.97 inches deep. The weight shall be 125 pounds. The loudspeaker system shall be a Peavey model SP 118X 4 Ohm.

3 + 2 YEAR LIMITED WARRANTY

NOTE: For details, refer to the warranty statement. Copies of this statement may be obtained by contacting Peavey Electronics Corporation, P.O. Box 2898, Meridian, Mississippi 39301-2898.

		Amplitude Response				(1W 1m On-Axis)
	120
Pa)	110
20	100
(re
dB SPL	90
	80
	70	50	100	200	500	1k	2k	5k	10k	20k
	20
	Figure 1				Frequency (Hz)

					Impedance
	100
	50
	30
	Z 20
(	) 10
	5
	3
	2
	1	50	100	200	500	1k	2k	5k	10k	20k
	20
	Figure 2				Frequency (Hz)