Hymn Crystal

Hymn Crystals (ヒュムネクリスタル, Hyumune Kurisutaru) also known by the name of Hymmne Crystals (Wave/Song Crystals in Hymmnos), are memory card-like devices that contain a program sealed with themselves. Said program always takes the form of a song (Hymmnos Extract) for the Reyvateils to sing it.

The Storage Qualities of the Hymn Crystals
Strictly speaking the Hymn Crystals are items similar to the Grathnode Crystals, but unlike them, they don't have any special qualities, and no matter how much energy or from which direction that energy comes, they can't be interfered. If one of these crystals was Installed in a Reyvateil, the wave interferences would cancel each other, and it wouldn't affect the Static H-Waves of the Reyvateil at all (in short, they have a GD Value of 0) The interferences are balanced out by the energy from the crystal, and the power center that exists within the FFT Spectrum of the crystal doesn't allow the interferences to be discharged either, allowing the crystal to keep its form eternally. The power center that keeps the FFT Spectrum constant is what allows the Hymn Crystal to record the [Feelings] = [Complete Deployment of the Static H-Waves of the Reyvateil]. The one that records the feelings in the crystal is the heart of the Reyvateil, but the balance inside of the crystal is what allows them to continue existing without allowing any loss of feelings.

GD = Grathnode Damage.

The Download Ceremony
During the chanting of the Hymmnos Spell for the execution of the Download, a perfect equilibrium is kept for the waves that are being recorded in the Reyvateil's mind in that instant, because what keeps that balance is the power that is being borrowed from the Tower. If the Hymn Crystals were Installed like the normal Grathnode Crystals, [It would be like breaking the shell of a egg of feelings], and these feelings would never go through to the mind of the Reyvateil. Because of the drawing of that preserved FFT Spectrum, and furthermore, the precise overlapping of the Static H-Waves of the Reyvateil, this is not only the act of accessing to the Cosmosphere from the Binary Field, but also the result of the execution of this command, the Download Hymmnos Spell.

The Download Hymmnos Spells varies depending on if the download is performed for an Standard Reyvateil or an IPD, and both versions are written below:

For Standard Reyvateils:

Was yea ra chs hymmnos yor. En chsee fwal fwal yor. Exec drone hymmnos XXXX Enter YYYY Was yea ra chs hymmnos yor. En chsee fwal fwal yor. Exec drone hymmnos XXXX Enter YYYY I shall be happy to turn you into a song, and into the wings I carry Execute the download of the song XXXX into the Reyvateil YYYY

For IPDs:

cEzYA hymmnos. #XXXX --x tArm azit tn='(YYYY)' es tn=>sol.infel-phira.mea cEzYA hymmnos. es tn=>sol.infel-phira.mea I shall be happy to turn you into a song, Deploy the song YYYY out from the Hymn Crystal #XXXX, and download it into me, who resides within Infel Phira.
 * 1) XXXX --x tArm azit tn='(YYYY)'

Why the Songs are Crafted Instantly?
When the download is complete, the song gushes forth by itself. This is because of the overwriting done by the FFT Spectrum that was recorded on the Hymn Crystal, expanding an entire spectrum of feelings on the time axis (in all the wave frequency zones, in all the time zones) in just an instant, and the Spectrum condition then becomes: [In process of crafting a song]. If we look at this through the perspective of the Reyvateil that downloaded the song, she feels like she had known the song from a long time ago, and within her own feelings and memories... the song is born, like an small bird.