by ramiller » Fri Apr 01, 2005 4:36 am
Hi Stan,
I have also noticed this burbling noise with the hiss filter. Its not unique to wave corrector--I have two other programs that also do noise sampling and filtering with about the same results with the exception that I can do less than -8db (which sometimes helps). I mostly convert lp's to cd, but have done a few open-reels and cassette's and have found this to help....
Get a noise profile from a blank, never recorded on tape. (an unbiased tape is usually quieter than an erased tape, the erase head, even on a blank tape can add 2 to 3 db noise... Sometimes a blank is actually noisier (rare) if it has been exposed to a magnetic field so be aware).
On a cassette use a high quality blank tape like tdk or maxell and record noise samples at 120 microseconds eq (normal) then 70 microseconds (chrome and metal) with dolby off, then repeat with dolbyB on. If you have an open-reel same applies but playback eq is 50 microseconds at 15 and 7.5ips and 90 at 3.75. Some late open-reels had EE settings (chrome tape) and eq is 35 at 7.5 and 50 at 3.75. The higher playback eq's give more hiss.
This will give a good noise profile for your tapedeck that will be added to anything you play on it. This works best if you always use same output level when you record. Also make sure everything is as clean as possible to get smooth tape travel. Different brands of tape will vary slightly, The quietest cassette tape is BASF true cromium dioxide according to a cross reference I once owned. Tdk and Maxell are cobalt treated ferric tape and about 2 db noisier (but can take about 3 db more above 0db therefore have a better sn ratio).
Append an appropiate profile to your wav file and use it for the filter profile. Usually this gives a more steady-uniform hiss that has less of the burbling noise, but I admit this doesn't always work--Tape scape on old worn tapes (especially open-reels) tends to be masked by the hiss, and brought out by the filter.
Randy
Randy