Even though a recording on tape may have been made at studio quality, tape speed was the limiting factor, much like bit rate is today. Decreasing the speed of analog audio tape causes a uniform decrease in the linearity of the frequency response, increased background noise (hiss), more noticeable dropouts where there are flaws in the magnetic tape, and shifting of the (Gaussian) background noise spectrum toward lower frequencies (where it sounds more "granular") "regardless" of the audio content. An MP3 of a noisy rock band at a low bit rate will have many more artifacts than a simple flute solo at the same bit rate, whereas either on low-speed tape will have the same uniform background noise profile and high frequency saturation (weakened high end response). A recording on magnetic audio tape is linear; unlike today's digital audio, not only was jumping from spot to spot to edit time-consuming, editing was destructive—unless the recording was duplicated before edit, normally taking the same amount of time to copy, in order to preserve 75-90 percent of the quality of the original. Editing was done either with a razor blade—by physically cutting and splicing the tape on a metal splicing block, in a manner similar to motion picture film editing—or electronically by dubbing segments onto an edit tape. The former method preserved the full quality of the recording but not the intact original; the latter incurred the same quality loss involved in dubbing a complete copy of the source tape, but preserved the original.