Thought of Keene noise from AR-DV1

I own AOR digital voice receiver AR-DV1. As mentioned in my Japanese blog article, "Keene Sound" from AR-DV1 bothers me.

I'm sure that the AR-DV1 generates the audible Keene Sound itself but some people says "I cannot hear that sound". So I check the fact.


First, I could not find whether the output source of the noise is the speaker, then I plugged a stereo mini plug cable into AR-DV1's PHONES jack.

Nothing could be changed. That means that the Keene sound seems to generate internally, not from the speaker.

Second, I tried to record the noise that comes from AR-DV1 and to analyse the audio spectrum.

* test equipments
 - AOR AR-DV1 Japan Version
 - SONY ICZ-R250TV (IC Recoder, for the Japanese market only, built in stereo microphones)
 - WaveSpectra software for the audio spectrum analysis
 - PC for the audio spectrum analysis

ICZ-R250TV has 44.1kHz/16bit linear PCM uncompressed recording function and can record & playback upto 20kHz.

The test is as follows;
1) record AR-DV1 Keene noise using ICZ-R250TV
2) check the audio spectrum using WaveSpectra

And the result is here;

(at AR-DV1 shutting down)

(at AR-DV1 receiving D-CR mode)

Actually the fact that some audible high frequency noise generated from AR-DV1 as above has been found. The peaks are about 9.6kHz, 12kHz, 14.5kHz, 17kHz and 19.5kHz.

The 19.5kHz might be an aliasing distortion.

Those're high frequency and some people might not hear the sound, I think. I ain't "The man Who Cried Wolf".


Now one of my embarrassed things has just been cleared. I won..... oh, did not win because the true problem "to stop the audible noise from AR-DV1" not cleared yet.

My fight against the mosquito noise JUST begun.