Auto Agc And Manual Level Recording

[guymrob]

Hi everyone,

I'm using the MZ-RH10 to do PCM recording via optical on the Hi-MD disc and playback on my Sennheiser PX-200 headphone.

I noticed when I set to manual recording level at 23, which is actually 0dB (calibrated using a test CD), the sound is much closer to the original source. When set to Auto AGC, the highs are somehow emphasised or brighter which tends to sound a bit harsh.

Has anyone encountered this?

Guy

[dex Otaku]

I've never noted any difference in frequency response, but a difference in the overall sound is perfectly normal. AGC = compression+limiting [probably compression with a low ratio starting at a certain amplitude with its ratio increasing to infinity:1, which is limiting, at a point above it and below 0dBfs].

It's possible that:

* the compression reacts faster to high frequencies, making the compression more noticable at high frequencies, or even that

* the compressor/limiter [AGC] uses some form of equal loudness contouring [which in this case would have to be broken for highs to become more noted during loud passages], or worse yet that

* there is actual signal emphasis applied before compression

In any case, the AGC should be using a full-bandwidth compressor, which should not make any particular range louder than all others - at least, not without it being louder than all others to begin with.

Side note - your calibration is different from mine, but then - your CD player may have a lower output, or the test CD may be using a lower than 0dBfs test tone. Unity gain on my HiMD recorders [NH700 and RH10] is at the cusp of 18-19/30 using a 1Vp-p input signal as reference. According to Sony, the middle dot on the recording meters is -12dBfs, and starting from the 1Vp-p reference as 0dBfs, -12dBfs from the same source is measured precisely at the -12dBfs mark.

It's sort of interesting that 1Vp-p = 0dBfs, actually, since that follows neither of the most common [pro and consumer] calibrations for what voltage = 0dBVU [here 0dBVU is basically -12dBfs].

[ROMBUSTERS]

i have noticed that AGC does cause portions of the music to PLAY louder than others however this is just a results of the AGC compensating for the varying volume levels of the source audio

[dex Otaku]

i have noticed that AGC does cause portions of the music to PLAY louder than others however this is just a results of the AGC compensating for the varying volume levels of the source audio

←

Well, yes. That's the whole point of compressor/limiters.