The Collaborative International Dictionary of English v.0.48:

Blare \Blare\, v. i. [imp. & p. p. Blared; p. pr. & vb. n.
   Blaring.] [OE. blaren, bloren, to cry, woop; cf. G.
   pl[aum]rren to bleat, D. blaren to bleat, cry, weep. Prob. an
   imitative word, but cf. also E. blast. Cf. Blore.]
   To sound loudly and somewhat harshly. "The trumpet blared."
   --Tennyson.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

blaring \blar"ing\ adj.
   harshly or unpleasantly loud (in sound intensity); -- used
   mostly of electronic entertainment devices, such as TV,
   radio, or phonograph.
   [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

blaring
    adj 1: unpleasantly loud and penetrating; "the blaring noise of
           trumpets"; "shut our ears against the blasting music from
           his car radio" [syn: blaring, blasting]
    n 1: a loud harsh or strident noise [syn: blare, blaring,
         cacophony, clamor, din]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "blaring":
   atmospherics, blasting, blatant, blatting, blind spot, blustering,
   boisterous, brassy, brawling, brazen, clamant, clamorous,
   clamoursome, clanging, clangorous, clattery, crawling, creeping,
   drift, earsplitting, fade-out, fading, interference, mafficking,
   noise, noiseful, noisy, obstreperous, piercing, rackety, reception,
   rip-roaring, roaring, rowdy, static, stentorian, stentorious,
   strepitant, strepitous, tumultuous, turbulent, uproarious,
   vociferous