Part 3 : spectrum comparisons

Spectrum

The Spectrum allows to check the tonal balance of the music (balance between treble, medium and bass sounds) and to detect process that may have been carried out during the recording, the mixing, mastering or manufacturing phases. It is also possible to detect frequency interference issues.

The curve represents the average frequency distribution over the sample “Oxygene 2”.

The interesting features on this curve Ed1 vinyl are the following:

The two curves representing vinyl and CD are very similar
We can see an increase of the treble above 10 kHz compared to the CD version (Ed2) (yellow arrow).
The red arrow shows the frequency limit at 22 kHz due to a sampling of 44.1 kHz as for the CD. We can conclude that the vinyl was made with a digital master in 44.1 kHz

Spectrum Ed1 Vinyl (white) vs Ed2 CD (blue)

For the spectrum of Ed2 CD (white) vs Ed3 Bluray PCM stereo (blue) the characteristics are:

The two curves are slightly different on the whole spectrum, this is due to the different mixes between the album version of the CD and the concert video version of the Bluray.
The yellow area shows the difference in the bandwidth limit between CD in 44.1 kHz which cuts at 22 kHz and Bluray in 48 kHz which cuts at 24 kHz.

Spectrum Ed2 CD (white) vs Ed3 Bluray PCM stereo (blue)

The graph below shows the difference between the bluray concert video PCM (Ed3) and the vinyl (Ed1). As you can see, we notice differences on the whole bandwidth, with more treble for the vinyl (yellow arrow) and the red arrow which shows that the vinyl has been mastered in 44.1 kHz.

Spectrum Ed3 Bluray PCM stereo (white) vs Ed1 Vinyl (blue)

The graph below shows the difference between Streaming Amazon Music (Ed7) and the vinyl (Ed1). As you can see, we notice differences on the whole bandwidth, with more treble for the vinyl (green arrow) and the yellow area which shows that the streaming cut off at 20 kHz.

Spectrum Ed7 Streaming Amazon Music (white) vs Ed1 Vinyl (blue)

The graph below shows the difference between the binaural (Ed6) and the CD (Ed2).

The binaural processing plays on the frequencies to give the sensation of volume, which explains the differences between the frequency curves.
The yellow arrow shows that in spite of a 48 kHz sampling frequency, the limit is similar to the CD in 44.1 kHz.

Spectrum Ed6 Binaural (white) vs Ed2 CD(blue)

The spectrum representation of the 5.0 editions in Dolby and DTS are similar, the use of the lossless encoding of these two formats allows to have a great fidelity with the original.