Converting tape to digital: muffled sine wave effect on tape

[richardr]

Hello. I am working on a project to convert all the music tapes I have to digital format. So far it's going ok. My set up is using a stereo cable from the headphone jack of a tape player to the line in on my built in sound card. I usually can edit out the noise and the quality is ok. However I have some tapes that have an effect I cannot explain in a single word. The effect is like taking a pillow and putting it up against the output, then take it away, and put it back, etc., etc., like a muffled sine wave. This sound is heard on play back on tape decks so it's not my pc, windows or audacity. So I am wondering if any one knows what filter effect I could use to fix it? or maybe something i can do to the tape itself?

[waxcylinder]

Are you playing these problem tapes on a different tape deck to the one on which they were recorded - or maybe you have had the deck serviced?

Tapes can be sensitive to the alignment of the record/replay tape heads - so it is often best to play them back on the machine that recorded them.

WC

[richardr]

The music tapes were bought years ago from music dealers even before CD was invented lol. So they aren't some specially recorded ones. I just have a few that have the sine wave muffle sound. Like for example Barron Cross: Atomic Arena the last song (and best song to some people) has it the worst compared to the rest of the tape. So I guess I could try to clean the tape headers and rollers to see if that helps (doubt it, since i think the tape is warped).

[waxcylinder]

Yup cleaning the drive of the deck will likely help. But if you have had the deck for some time then the rubber parts may have perished or hardened (I had my Nakamichi professionally overhauled before I tackled digitizing my tapes).

Good luck - hope you get it to work

WC