Constant minecart sound

Please force a crash by pressing F3 + C for 10 seconds while ingame and attach the crash report here.

---- Minecraft Crash Report ----
// You should try our sister game, Minceraft!

Time: 7/19/13 3:12 PM
Description: Manually triggered debug crash

java.lang.Throwable
	at ats.k(SourceFile:1238)
	at ats.S(SourceFile:663)
	at ats.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bdf['stidder'/49, l='MpServer', x=16.70, y=38.68, z=852.30]]
	Chunk stats: MultiplayerChunkCache: 441
	Level seed: 0
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: World: (46,4,876), Chunk: (at 14,0,12 in 2,54; contains blocks 32,0,864 to 47,255,879), Region: (0,1; contains chunks 0,32 to 31,63, blocks 0,0,512 to 511,255,1023)
	Level time: 528816 game time, 30000 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
	Forced entities: 10 total; [tr['Slime'/1388, l='MpServer', x=24.78, y=33.00, z=856.44], rx['Pig'/16, l='MpServer', x=89.06, y=32.00, z=775.94], rx['Pig'/18, l='MpServer', x=83.16, y=32.00, z=777.97], ry['Sheep'/5, l='MpServer', x=3.72, y=32.00, z=779.63], bdf['stidder'/49, l='MpServer', x=16.70, y=38.68, z=852.30], sr['item.tile.oreGold'/8, l='MpServer', x=28.28, y=32.13, z=872.53], sr['item.tile.oreGold'/9, l='MpServer', x=27.88, y=32.13, z=874.72], sr['item.tile.oreGold'/10, l='MpServer', x=28.66, y=32.13, z=875.66], st['entity.MinecartChest.name'/12, l='MpServer', x=34.50, y=26.50, z=848.16], rx['Pig'/15, l='MpServer', x=78.06, y=32.00, z=784.06]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bda.a(SourceFile:284)
	at ats.b(SourceFile:1761)
	at ats.d(SourceFile:628)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.2
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 153218136 bytes (146 MB) / 364249088 bytes (347 MB) up to 1908932608 bytes (1820 MB)
	JVM Flags: 1 total; -Xmx2G
	AABB Pool Size: 9260 (518560 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.6.2
	LWJGL: 2.9.0
	OpenGL: AMD Radeon HD 6290 Graphics       GL version 4.1.10834 Compatibility Profile Context, ATI Technologies Inc.
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Default
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 257 (14392 bytes; 0 MB) allocated, 13 (728 bytes; 0 MB) used

Nothing to see in the crash report.

Confirming, happened to me a few times too. The particular circumstances usually involve a moment of lag just when the minecart (with player character inside) is starting (launched from a booster track activated by button, the lag may be of external origin, say, Firefox updating a webpage in the background and simply taking up all CPU power for half a second or so), The minecart starts moving noiselessly, while the sound source remains stuck to the location of start, independent from the minecart's fate or speed. You can hear the noise coming from some point near the origin of the track, it vanes as you go away.

Sometimes the glitch vanishes if you start the minecart anew elsewhere, more often it remains there until restart while minecart movement remains silent. I can't swear by it but I believe it survived the game restart once too.
Repeating is difficult because it depends on the game "hiccuping" (a moment of lag) while riding the cart.

This happened to me too. Even when I quit the world, and went on a new one it continued. Beyond annoying.

Thanks so much for your support this is a really annoying glitch,
it is now in the 1.7.1. pre-release change-log.
Thanks dinnerbone for fixing this issue.