Here is the excerpt from the article "Russian phonology" in Wikipedia Voicing Russian features general regressive assimilation of voicing and palatalization. In longer clusters, this means that multiple consonants may be soft despite their underlyingly (and orthographically) being hard. The process of voicing assimilation applies across word-boundaries when there is no pause between words. Within a morpheme, voicing is not distinctive before obstruents (except for /v/, and /vʲ/ when followed by a vowel or sonorant). The voicing or devoicing is determined by that of the final obstruent in the sequence: просьба [ˈprɵzʲbə] ('request'), водка [ˈvotkə] ('vodka'). In foreign borrowings, this isn't always the case for /f(ʲ)/, as in Адольф Гитлер ('Adolf Hitler') and граф болеет ('the count is ill'). /v/ and /vʲ/ are unusual in that they seem transparent to voicing assimilation; in the syllable onset, both voiced and voiceless consonants may appear before /v(ʲ)/: - тварь [tvarʲ]) ('the creature') - два [dva] ('two') - световой [s(ʲ)vʲɪtʌˈvɵj] ('of light') - звезда [z(ʲ)vʲɪˈzda] ('star') When /v(ʲ)/ precedes and follows obstruents, the voicing of the cluster is governed by that of the final segment (per the rule above) so that voiceless obstruents that precede /v(ʲ)/ are voiced if /v(ʲ)/ is followed by a voiced obstruent (e.g. к вдове [ɡvdʌˈvʲe] 'to the widow') while a voiceless obstruent will devoice all segments (e.g. без впуска [bʲɪs ˈfpuskə] 'without an admission'). /tɕ/, /ts/, and /x/ have voiced allophones ([dʑ], [dz] and [ɣ]) before voiced obstruents, as in дочь бы [ˈdɵdʑ bɨ] ('a daughter would') and плацдарм [pɫʌdzˈdarm] ('bridge-head'). Other than /mʲ/ and /nʲ/, nasals and liquids devoice between voiceless consonants or a voiceless consonant and a pause: контрфорс [ˌkontr̥ˈfors]) ('buttress').

Привет! Мы не решаем этот вопрос сами, а знаем, что существуют парные согласные. Например: б-п, в-ф, г-к, д-т,ж-ш, з-с, где первая согласная звонкая, а вторая глухая. Ваши примеры: 1) солДат орГан гороДа стуДент Ответ: звуки Д и Г звонкие. 2)асТра ленТа оркесТр Ответ: звук Т глухой 3)синТаГма ( Т- глухой, Г- звонкий ) оДумТься ( Д- звонкий, Т- глухой) Надеюсь, что смогла объяснить :)

In short: Russian has regressive voice assimilation in obstruent clusters (= stops and fricatives clusters). The voicing or devoicing is determined by the final obstruent in the cluster (some foreign borrowings could be exceptions). Voice assimilation can occur within a morpheme, across morpheme boundaries, as well as (inconsistently) across a word boundary (stress, speech tempo and individual variations can play the role here). Vowels and sonorants ([m], [n], [l], [r]) don't usually trigger voice assimilation neither in word-initial nor in word-medial stops: солдат [sal'dat] орган [ 'orɡan] города [ɡora'da] студент [stu'dʲɛnt] астра ['astrə] лента [lʲ'entə] оркестр [ɐrkʲ'estr] синтагма [sʲin'taɡma] одуматься [a'dumat͡st͡sa]

I can demonstrate. I don't know how to describe a sound. Visit some lessons?

What is "stop consonants"? From your examples I don't understand :( All writed by big leeters consonants are pronounced as writen.