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How recordings are restored

How can your recordings sound better than new? Records can have scratches and rumble noise removed. Tapes can have hiss removed. The restored recordings will sound better than the original source!

Prior to recording, records are cleaned with a soft microfiber brush and mild cleaning solution to remove dust and dirt lodged deep in the grooves, then vacuumed dry. So your records are cleaner than when they came out of the shrink wrap!

The original recording is played on audiophile-quality equipment into the computer and saved in a lossless file format at CD quality settings. (44,100 samples per second, 16bit stereo sound)

Warped records or cylinders that will not play at their rated speed can be recorded slow and speed corrected to sound normally. 78rpm records can be recorded at 45rpm or 33rpm. 160rpm blue amberol Edison cylinder records can be recorded as slow as 40rpm.

Skips and locked grooves (skips jump forward, locked grooves jump back and repeat) may be repaired using a microscope, fine tools, patience, and a modest fee.

Encoded recordings are run through the appropriate decoder: CX, Dolby B and C, and dbx can be decoded.

Tapes go directly into the computer. Records go through a custom low noise preamplifier with an active rumble cancellation circuit and variable equalization settings. The variable equalization is required because the RIAA playback eqalization curve (red line) was standardized only in the 1950s.

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Prior to that, there were numerous "standards" employed, (blue lines) and acoustic records used no equalization at all. (purple line)

Listen to a Bob Hope transcription record played back using the correct equalization,
and using the wrong equalization (RIAA).
Note the boomy bass and missing highs in the RIAA playback.

Software then examines the audio files and removes clicks, pops, scratches, and tape hiss, leaving the original audio untouched. It not only removes the big clicks, but it goes after the little ones you can barely hear.

When it detects a click, (red line) it looks at the surrounding waveform, and replaces it with what it thinks it should look like. (blue line)

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The above image is an actual screenshot of the declick software doing it's thing.

Analog click suppressors just blank out the offending click and your brain fills in the blank spot, if it's not too big. (If it is too big, you'll hear it.)

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The image above is a simulation of what would happen with the same audio sample.

This process takes some time, due to the complex computing necessary.

All tracks are faded in and out to eliminate the noise inbetween tracks. This is done by hand, since many automated track dividers put them in the wrong places.

The software also has it's own rumble filter to further quiet the recording.

although the software handles clicks, pops and dust very well, what it doesn't like is long scratches made by damaged or contaminated grooves.

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Artifacts from these will remain after processing.



The cleaned audio files are burned to CDRs that are playable on almost any home or car CD player, or an MP3 CD can be made for uploading to your smart phone. The CDRs used are the silver/silver phthalocyanine type estimated to last 100 years. The audio files can also be recorded to a cassette or reel to reel tape deck using Dolby B or C, or dbx noise reduction.
Jacket art is scanned and printed for the jewel case inserts and a label is printed on the CD itself, as paper labels can peel off or jam some CD players.
Custom charicatures, cartoons and illustrations can be made for the CD labels and jewel case inserts.

picture For ultra-analog purists, any recording can be run through an analog blanking type click supressor, avoiding the use of the computer, and recorded to cassette or reel to reel tape. This will of course remove most, but not all, clicks. Very small ticks will be heard, and very large click artifacts may be heard.


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Mail recordings to:
Precision Audio Restoration
14419 Greenwood Ave. N., Suite A, Box 321
Seattle, WA 98133
Call 206-387-5662 or email to receive
directions to drop off recordings personally.
By appointment only.

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http://www.precision-ar.com/proc.htm