The VHS format was a workhorse for everything from recording sporting events and TV shows to capturing family movies on full-sized and compact VHS camcorders. But the Achilles heel of this format, and Sony's Betamax for that matter, was the audio quality on VCRs and camcorders from the mid 1970's through the early 1980's. During this time period, machines had a mono linear audio track that was a small stripe on the bottom edge of the VHS tape. A few models had a linear stereo feature with the mono track split in half delivering worse fidelity than the mono sound and VCR manufacturers resorted to using Dolby to keep the noise levels down. Movie studios started to release VHS titles with Dolby-encoded linear soundtracks in 1982 but linear stereo never caught on with VCR makers or consumers.
For Extended Play/Super Long Play (EP and SLP) recordings, audio was even worse. Signal-to-noise ratio dropped significantly and frequency response peaked at a very low 4 kHz on EP/SLP tapes. In non-technical terms, the sound was pretty awful. JVC introduced VHS HiFi sound in 1984 and the sound quality was comparable to CD audio. Unfortunately, the quality of HiFi audio degraded quickly because of the design physics (narrow tape, rapidly
spinning helical tape head) so the very good HiFi audio often didn't sound the same 5 or 10 plays later. For backward compatibility, VHS HiFi machines had both HiFi audio heads and linear audio heads so that a HiFi recorded tape would also play back in a VCR that only had mono sound.
So what does this mean for audio on your VHS, S-VHS or compact VHS tapes? It depends on how the sound was recorded on the camcorder or the VCR. For a camcorder with HiFi sound capability, tapes recorded in Standard Play (SP) mode and you have the original camcorder tapes, the audio should be pretty good. But if you had a mono sound or linear stereo camcorder or you recorded in EP mode (or both), then the audio could benefit from some help. Also, if your camcorder tape was recorded in HiFi audio but you made a copy to a mono sound or linear stereo VCR, then the VCR tape you have digitized will have mono or linear stereo sound - not HiFi sound.
Audio cleaning software is one way to improve sound on your VHS tapes. If you have already digitized your tapes, the video files will contain both the audio and video tracks. Otherwise, you will need to transfer your tapes to one of the file formats used by video and audio cleaning tools (.mov, .mp4, .mpeg, .avi).
Unlike years past, software for cleaning sound tracks on your video tapes no longer requires
an engineering degree. If you can use Photoshop Elements or Excel, you will be able to learn most audio cleaning programs. Current software such as SOUND FORGE Audio Cleaning Lab 2 is menu driven with graphic dials to quickly apply filters to your audio. Before and After buttons let you hear the original video tape audio and the 'fixed' version. Once you're happy, click the 'Export' option and save your new video file with the improved sound track. A few of the problems audio cleaning software can fix include:
Removing camcorder motor noise
Eliminating electrical noise
Removing tape hiss
Reducing wind noise
Lowering train or car noise
Eliminating voice 'clipping'
Lowering hum or rumbling noises
Removing clicking or crackling sounds
Providing equalizer settings for voice, music or venue
For digitizing vinyl and audio cassettes or using a background song for your video, filters for record pops and tape hiss will dramatically improve your sound. And audio improvements will be noticeable even with video taken from phones, digital cameras and camcorders. One common issue in video taken with SLR cameras is the microphone location being too close to the zoom lens motor. Software filters can remove or drastically reduce this motor noise.
Advances in ease-of-use with audio enhancement software allows non-technical consumers to make noticeable improvements to the audio tracks on their video tapes, audio cassettes, digitized vinyl records and Super 8 sound films. If you don't feel like learning new software, then check with a video editing vendor to see what programs they have to let your audio tracks reach new heights.