Τονικός ρυθμός / Accent-based rhythm

Here is the definition of this type of rhythm by Angelos Boudouris (taken from this translationof his Introduction to Byzantine Music),

§306. In fast Heirmologic pieces, there rarely is regular rhythm. In such chants, the "tonikos" [accent-based] rhythm is appropriate ("prosidiazei"), which is based on the accents of the words and therefore renders clearly the words and helps [the listeners] in following the meaning of troparia.

§307. In Heirmologic pieces, the grammatically emphasised syllables are represented by characters (signs) carrying one of the quality signs, like psephiston, vareia, omalon in particular, and those syllables become the beginning of a bar. Mainly such chants are chanted in monosemos [single chronos] also known as chronos aplous [simple chronos].

Here is an example of true accent-based (irregular) rhythm, as described by Boudouris, from a live recording from the Patriarchate:

Heirmos "Efrikse Paidon Evagon"

Leonidas Asteris
[mp3,80 Kb]
(from mpa.gr)

Now here is an example of "chronos haplous" where each syllable is emphasised to an extreme degree:

The same piece chanted by the
Choir of Theodoros Vasilikos
[mp3,200 Kb]

Here is another example of accent-based rhythm

Prosomion Olin apothemenoi

Leonidas Asteris
[rm, 275 Kb]
(from ec-patr.net)

Compare the Patriarchal style as expressed by L. Asteris to the following example with irregularities and softer stresses

Harilaos Taliadoros
[wma,320 Kb]

Here is another example of an accent-based rhythm

Idiomelon of the Holy Week Simeron o Christos

Leonidas Asteris
[mp3, 320 Kb]
(Live from the Patriarchate)

and another interpretation

Konstantinos Bilalis and Athanasios Papathanasiou
[mp3]

Compare these to the following example of the haplos chronos where each syllable is emphasised

Charalampos Karakatsanis
[mp3,800 Kb]

Now compare the above examples to the following one, where frequent instances of speeding up/slowing down affect the rhythmic structure of the piece

Fotis Ketsetzis
[m4a]
(from archondes.com)

Here is another example of a haplos chronos

Apolytikion Tou lithou sfragisthentos

Georgios K. Michalakis
Extracted version in haplos chronos
[wma,200 Kb]
Whole teaching session
[wma,6 Mb]

For more examples and comparisons see the general performance comparison page [html].