¥ 29,800 (around 1982)
This graphic equalizer checker (characteristic measuring instrument) combines a wobble tone generator with a sound level meter and a condenser microphone.
The measurement frequency can be set to 31 points in 1/3 octave steps in the 20 Hz to 20 kHz band with a rotary frequency selector switch and a push-type 3-stage range selector switch that emphasize accuracy and operability.
Warble tone is used as the signal for measurement.
A wobble tone modulates the frequency of an oscillating signal with another low-frequency signal. Because the phase of the wobble tone changes constantly with time, the phase relationship between the direct sound from the speaker and the reflected sound changes constantly. This averages the relationship between enhancement and cancellation, preventing the occurrence of standing waves.
In addition, stable measurement is possible even in the low frequency range, and sound field measurement can be carried out in a condition close to music signal.
Equipped with a protect switch to prevent damage to the tweeter due to excessive input when measuring in the high frequency range (10 khz or more).
Five sound level switches (50, 60, 70, 80 and 90 dB) and a level meter (± 15 dB scale) enable direct reading of sound pressure over a wide range from 35 dBSPL to 105 dBSPL with an accuracy of 1 dB per scale.
In addition, the meter response speed can be switched between slow and fast. When the meter is in the slow position, it is indicated on the average for the warble tone, and stable measurement is possible.
A back electret condenser microphone (non-directional) is used as the microphone for measurement. The diaphragm is made thin by charging the fixed electrode at the rear of the vibrating piece.
Equipped with a battery check switch.
Comes in a portable carton box.
|Type||Audio Frequency Analyzer|
|Oscillation signal||Wobble Tone (modulation frequency : 8 Hz)|
|Oscillation frequency||20, 25, 31.5, 40, 50, 63, 80, 100, 125, 160, 200, 250
315, 400, 500, 630, 800, 1k, 1.25k, 1.6k, 2k, 2.5k, 3.15k
4k, 5k, 6.3k, 8k, 10k, 12.5k, 16k, 20 kHz
(Measuring point : 31)
|Frequency accuracy||+ / - 6 per cent|
|Rated output / output impedance||70mV/1k Ω|
|Sound pressure measurement range||35 dB to 105 dB SPL (0 dB = 2x10-4Microbar)
(50 dB ~ 90 dB 10 dB step 5 range switching)
|Meter response speed||FAST : 350 msec rise, 400 msec fall
SLOW : rise 550 msec, fall 2 sec
|Pwer||9 v Battery (S-006Px1)|
|Battery life||10 hours (continuous operation)|
|External dimensions||Width 430x Height 53x Depth 158 mm|
|Type||Back electret condenser type|
|Front sensitivity||-72dBV / μ bar at 1 kHz|
|Frequency characteristic||20 Hz to 20 kHz|
|Maximum input sound pressure||110dB SPL(0dB=2x10-4Microbar)|
|Output impedance||600 Ω unbalanced type|
|Battery life||1500 hours (during continuous operation using National High Top)|