Mono Encoding error ?

[Ilya]

when i encoding in mono mp3 my stereo wav file wav pcm 16 bit stereo (ref 16.5), i can choose 2 options: 1) put the "channels" in mono and 2) add the keys "-m m" in the line Additorial CLI. I always did 1). But yesterday I tried 2), putting the channels in * as sourse * Bitrate 128. As a result, I got twice the file size (compared to 1)) and a voice like a monster from the underworld. You did not foresee such a situation for Lame? The same question about the frequency of sampling. "Frequency"?

[Ilya]

Re: Mono Encoding error ?

And I noticed that your regular Lame conversion of mp3 stereo in mono mp3 raises the volume of the output file. And the lame does not do this through the command line.

[Spoon]

Re: Mono Encoding error ?

You are best using DSP effects to reduce to mono, such as 'Channel Count'

[Ilya]

Re: Mono Encoding error ?

thanks for the hint about the dsp effect. Although this effect also increases the volume of the resulting file. Unlike the command line.

And why all the same there is no such effect of normalization, that is, that it occurred before compression in mp3, and not after? After all, this is considered more correct (or is it not, and there is no difference)?

[Spoon]

Re: Mono Encoding error ?

Going 2 channel to 1 should increase the volume, it is standard practice to do this, because if you have properly stereo separated audio then going 50% + 50% of each channel would be overly quiet if there was only audio in one channel.

You can use the DSP effect 'Channel Mapper' to map 50% + 50% of L + R if you so wish, however it is not optimal.

[schmidj]

Re: Mono Encoding error ?

The amount of "gain" you get when combining two audio sources of equal amplitude (like stereo to mono) depends on the characteristics of the audio in the two channels. If the audio in the two channels is identical and coherent, you will get 6dB higher level in the sum. Examples: the same tone (from the same source) in each channel, the same mono program material in each channel. The voltages add, and since they are identical, you get twice the voltage, which is 6 dB. If the material is of equal level but not coherent, you will get three dB of increased level. Examples, two different sources of white noise, two different pieces of music, anything where the audio in one channel has no relation to the other. The voltages still add, but statistically, they won't be equal at any given point. If you have two identical sources that are of reversed polarity, you will get zero out, they will cancel.

At ABC where I designed audio systems for many years, we padded mono sums of stereo audio by 6 dB, as the source material was often speech that was coherent or nearly so in both channels, and would sum by 6 dB. And if it was music that wasn't coherent it would be a little soft, better than having the music sum matching the source channel loudness, but having speech so loud it ended up in clipping.

One side effect of this is if you have a pop music recording where the vocalist is panned center, but the instruments are "spread" to the two channels, the mono mix will have noticeably more vocal in the mix, as the vocal gains 6 dB in the sum, but the instrumental music only 3 dB. There are various ways to avoid this, best at the time when the music is mixed by shifting the phase of the vocal differently in the left and right channels, but also at summing time by playing with the phase of the left and right channels before mixing them.

some better audio consoles and most software editors give you the choice of the summing gain, often part of the "pan laws" setting.

[Ilya]

Re: Mono Encoding error ?

2 Spoon: Many thanks. Your last advice is exactly what I wanted to achieve with the help of the program. I set: Set channel count: "1 mono" , Channel 1: from channel 1 (0dB, 100%) . Now I do not need an intermediate program that turns the stereo wav file into mono. The method works equally well with both the lame encoder and FhG and Helix. And even if I submitted a mono wav file to the input, I do not need to reconfigure and disable the dsp effect. After setting up and using. Simply super. Thanks again.

2 schmidj: Thank you, too. I have two dictophones. One can customize the recording format. and I put mono wav. The other one always writes in stereo. Although the microphone is mono. And it is because of the second voice recorder that the question arose. He simply writes 2 absolutely identical tracks. Also I will add that such programs as Sound Forge, Adobe audition, Nero Wave editor, the LAME itself (cmd) and helix (cmd) from the command line keep the stereo wav in mono mp3 without increasing the volume. Increases the volume only the "Kanz Software sound normalizer". Well and dbpoweramp )