The Collaborative International Dictionary of English v.0.48:

Sepulchral \Se*pul"chral\, a. [L. sepulcralis: cf. F.
   s['e]pulcral.]
   1. Of or pertaining to burial, to the grave, or to monuments
      erected to the memory of the dead; as, a sepulchral stone;
      a sepulchral inscription.
      [1913 Webster]

   2. Unnaturally low and grave; hollow in tone; -- said of
      sound, especially of the voice.
      [1913 Webster]

            This exaggerated dulling of the voice . . . giving
            what is commonly called a sepulchral tone. --H.
                                                  Sweet.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sepulchral
    adj 1: of or relating to a sepulchre; "sepulchral inscriptions";
           "sepulchral monuments in churches"
    2: gruesomely indicative of death or the dead; "a charnel smell
       came from the chest filled with dead men's bones"; "ghastly
       shrieks"; "the sepulchral darkness of the catacombs" [syn:
       charnel, ghastly, sepulchral]
    3: suited to or suggestive of a grave or burial; "funereal
       gloom"; "hollow sepulchral tones" [syn: funereal,
       sepulchral]

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "sepulchral":
   baritone, bass, cavernous, cinerary, contralto, deep, deep-echoing,
   deep-pitched, deep-toned, deepmouthed, dirgelike, dismal,
   epitaphic, exequial, feral, funebrial, funebrious, funebrous,
   funeral, funerary, funereal, grave, heavy, hollow, low,
   low-pitched, mortuary, mournful, necrological, obituary, obsequial,
   reverberant