Continuity mistake: Alvin pushes over a packet of Cheese Balls and they fall from the cupboard and into a bowl that is on the kitchen counter. He then cannon-balls from the cupboard into the bowl of Cheese Balls which causes a lot of them to fall out of the bowl, spilling all over the counter. However when Dave walks into the kitchen and spots the bowl, the amount of cheese balls on the counter (around the bowl) is much less. (00:11:15)
Continuity mistake: When Dave gets back from work and is lying on the couch, on the counter behind him you can see two jars (one with a green lid and the other with a white lid.) But later when Dave notices the bowls moving across the same counter, the glass jar with the white lid has now vanished. Also the magnets and papers on the fridge differ as well. (00:10:35 - 00:11:50)
Visible crew/equipment: When Dave first discovers that the chipmunks can sing, as they perform on the tree stump outside his window for him, after they sing 'Funky Town' there is a shot from outside looking through the window and to the right of Dave (through the window) you can see the long pole of the boom microphone; it is not seen in any other shots. (00:16:55)
Continuity mistake: Once Alvin has opened up two of the food cupboards in the kitchen and all three of the chipmunks are rummaging around inside of them, the items that are inside of the cupboards themselves move about and rearrange themselves without the chipmunks touching them; for instance the items of food next to Alvin as he pours out the packet of Cheese Balls. (00:10:55)
Continuity mistake: When Dave throws the muffin basket inside the garbage can there is a clothing item hanging down off of the kitchen seating area, right next to the bin. However a few shots later when we see the bin, the seating is completely clear with nothing on it. But when the chipmunks climb out the bin the item is back on the seat, hanging over the side of it. (00:09:30 - 00:10:25)
Continuity mistake: When Dave arrives at Jett Records and gives Ian his CD, we see Ian putting the disc into a Bose CD player with no speakers; and next to the CD player is a stack of CD cases. However in following shots, the CD player we see now has speakers that are actually attached to the player itself (and this is the same CD player Ian is using.) Additionally the stack of CD cases next to the player is much higher as well. (00:06:05)
Continuity mistake: Dave throws the muffin basket that he stole from Jett Records into his garbage can; and when we see the front of the can there is a handle visible on the side. However when the film goes back to the garbage can (as the chipmunks climb out of it) the handle is no longer visible on the front part of the can that we see, meaning the can itself has somehow rotated. (00:09:30 - 00:10:25)
Revealing mistake: When the chipmunks are singing 'How we roll' there is a shot of Ian with some people in a private room. The music continues to play as they listen and the stage is reflected in the glass, how ever the chipmunks, back up singers, dancers, instrument players and audience are missing. (01:17:40)
Continuity mistake: When the chipmunks are in the recording studio they are too exhausted to sing their song, so Ian comes in with plastic cups of coffee for them. Above the chipmunks heads is a large silver microphone - during this whole scene the microphone alternates from being just above their heads to being much further above their heads. (01:04:00)
Visible crew/equipment: After Dave has retrieved all of his musical equipment and instruments from the rain outside, there is a shot of him wiping his damp keyboard down with a towel. In this shot if you look in the glass door behind Dave, you can see the hands of a crewmember and the long boom microphone that he is holding, reflected in the glass hovering above Dave. (00:18:20)
Continuity mistake: When Dave and Claire are having dinner together, the amount of white wine in Dave's glass is inconsistent during the scene. In the opening shots the glass is almost full, but when he picks it up to drink from it the level is much lower. Then when he puts it back down and the scene continues, the level differs during all the shots of dialogue between the two. (00:32:50)
Plot hole: When the chipmunks finally release their first song, there is a montage showing the chipmunks rising musical success. In one shot we see a marquee promoting "The Chipmunks Premiere CD Release", and on it is a picture of the chipmunks in the clothes Dave has made them (note Alvin in his 'A' jumper.) However, Dave doesn't actually make the chipmunks these clothes until further on in the film. (00:41:50)
Factual error: When Dave hears the message on his voicemail from Claire, telling him that she will be round for dinner at 7 o'clock, he checks the clock and it is 6:30.p.m. However, bright sunlight is pouring through the windows. This film is set around the countdown to Christmas, so at 6:30p.m it should be pitch black outside, or at least slightly dark but definitely not bright sunshine. (00:30:50)
Continuity mistake: When Uncle Ian is telling the chipmunks in the dressing room that they need to lip sync along to their song, there are alternating shots, and one of them is Ian and Alvin talking whilst being reflected in a large vanity mirror. However in the shot where Alvin turns around on the vanity table and tells Simon and Theodore they 'have to lip sync', Ian is not reflected in the large mirror, then in the next shot he has appeared back to where he was standing and is once again reflected in the mirror. (01:12:55)
Continuity mistake: When Ian visits Dave's house on Christmas, bringing over all the gifts and toys for the chipmunks, he hands Dave three large gift-wrapped boxes for them. He then mentions he got Dave a CD and places the wrapped CD on top of the three boxes that Dave is holding. Then when Ian is leaving, between a couple of shots the position of the wrapped CD on the top box differs. (00:48:30)
Continuity mistake: When Dave is in the supermarket with the chipmunks, the chipmunks are in the trolley. When Dave turns his back, the chipmunks overload the trolley with boxes of toaster waffles. In the following shots during the whole scene with Dave talking to the chipmunks and then discovering that the chipmunks' song is on the radio, the amount of boxes of waffles in the trolley and the boxes' positions change. (00:40:35)
Continuity mistake: When Dave catches Alvin from off the top of his head and traps him inside a woollen hat, he quickly places the hat down on the table and holds the rim of the hat down to prevent him from escaping. However, as he is holding it down the position of the rim of the hat and the actual hat (in his hands) differs from shot to shot. (00:13:15)
Continuity mistake: In the shot when we see the chipmunks climbing out of the garbage can that Dave threw the muffin basket into, we can see an ironing board surface to the right of the screen, with just a few items on it. Later on in the kitchen scene where Dave is chasing the chipmunks through the cabinets with a spatula, a whole pile of paper sheets and addition items have appeared on the edge of the ironing board. (00:10:15 - 00:12:45)
Continuity mistake: When the Chipmunks are running through the lobby of Jett Records, trying to get inside Dave's muffin basket, Alvin and Simon get in but Theodore is still running along trying to get in. As Alvin hangs over the edge to try and grab Theodore, he is alternatively standing on or off of the white material that drapes outside the muffin basket. (00:09:05)
Continuity mistake: When the chipmunks are in the kitchen, Alvin gets on top of the microwave and opens up two of the cupboards that are full of food. He opens them up and then stands at the ledge of the cupboard in awe, but in the next wider view of the open cupboards he isn't visible at all and has vanished from the shot. (00:10:50)
Answer: No it isn't his voice.