CONNECTING AND GETTING STARTED
If you have a reasonable quality cassette deck, connecting to your computer is quite easy. You will just have to connect the LINE OUT of your cassette machine to the LINE IN of your sound card. This connection is done in general by a simple lead having two CINCH male connectors on one end and a 3.25 stereo jack on the other. The red Cinch corresponds to the right channel and the white one to the left channel. This sort of connectiong cable can also have a 3.25 stereo jack on each end.
In fact you only have to look at the connectors at the back of your cassette deck and the connectors at the back of your sound card, and buy the right one. They can be found in many stores. ( Don't forget that one can also find diameter adaptors for varios connectors. )
The signal voltage comming out of a cassette deck does not need to be amplified. So no extra preamplifier.
One then only needs to transfer the audio signal from the cassette to your hard disk in the same way that was mentioned for transfering LP's.
AUDIO CASSETTE RECORDINGS
There are two types :
Private audio recordings.
These are recordings made by oneself from radios, microphones, other audio cassettes, CDR's or from LP's .... In this last case, one may operate on the audio file in the same way one does with LP copies. ( Noise reduction, pop and click elimination , normalization ... )
Commercial audio cassettes
These are the prerecorded things found in shops.
These two types of cassettes have something in common : Hush and Hiss.
Hush depends of course upon the quality of the electronics used but also depends upon the intrinsic quality of the tape used.
And as one could guess, the worst quality is very often found amidst the commercial cassettes.
This defect gets even worse if we are in presence of a copy of another tape.
With Cool Edit one can try to make things sound better.
NOISE REDUCTION
Noise reduction consists of subtracting from an audio signal any constant noise. This background noise can be a fixed frequency like hum. This procedure can be usefull to eliminate 50 or 60 Hz.
On the screen graph of Cool Edit select a portion which does not contain any music, bur only hum or hush. You'll need a selection of a few seconds (if possible)
Then in the menu :
Transform
Noise Reduction
Noise Reduction
Snapshots in Profile 100
Reduce by 40 db
Precision Factor 7
Smoothing Amount 1
Transition Width 0 db
FFT Size 6000
Click on Get Profile from selection
Eventually record this profile with Save Profile
Click on Close
Select a musical zone on your graph
And the once again :
Transform
Noise Reduction
Noise Reduction
Select Remove noise
Click on Preview
You should be able to hear the music with noise reduction.
By sliding the Noise reduction level you will be able to change the amount of noise reduction.
Full left : No noise reduction.
Full right : Noise reduction but with effect on the music.
It is up to you to find a "happy medium" and chose the amount by which the "Hush" will be reduced.
Once this is chosen, click on Close and remove any selection that may be still on Cool Edit's graph. Return to Noise Reduction and click on OK to apply to the whole graph.
Hush is a sort of "white noise" containing all the frequencies of the audio spectrum. So noise reduction may have a too great effect on the musical material. If this happens, you will have to change the default settings mentioned above. These settings in fact depend upon the type of content in the musical data.
Another way to evaluate the alteration of the music, is to select Keep only Noise before clicking on Preview. This time you will hear the noise removed with also small bits of music sounds. These must not be too loud.
On the two following graphs, one can see the effect of noise reduction on a audio signal.
 |
 |
|
| With Noise | Without Noise |
This simple noise reduction may be satisfactory in many common cases.
Example :
| Before Noise Reduction (174 Koct. mp3) |
After Noise Reduction (174 Koct. mp3) |
And nothing is to stop you in using this method to reduce surface noise in Vinyl recordings.
HISS REMOVAL
This function removes all frequencies under a given threshold. Signals of a higher level than this threshold will remain untouched. On the other hand, signals under this value will be cut. This threshold, as one could guess, is not a constant, but varies depending upon the frequency.
This methode is also useful for the elimination of hush.
As in the "Noise Reduction" method, one must select a portion the graph that has no music in it, and then,
By the main menu :
Transform
Noise Reduction
Hiss Reduction
Light Hiss Reduction
Standard Hiss Reduction
High Hiss Reduction
depending upon the hiss level.
Click on " Get Noise Floor ". The noise floor appears
( It is possible to modify this curve by pushing the little squares around with the mouse. )
Click On Close
Select a representative part of music on Cool Edit's graph.
Then by the main menu :
Transform
Noise Reduction
Hiss Reduction
Select Remove Hiss
Click on Preview
You should then hear the music with the hiss reduction function.
By sliding Noise Floor adjust , you will apply more or less hiss reduction.
Full Left, no hiss reduction.
Full right, total his reduction, but with musical alteration.
It is up to you to find the right level.
Once found, click on Close and deselect any selection on the graph. Come back to Hiss Reduction, and click on OK.
Another way to evaluate the musical alteration is to select Keep only Hiss before clicking on Preview. You then hear the hiss that will be removed.
It is up to you to adapt the general settings to your tape. The FFT Size seems to be the most important.
In the same way, you can also record the sound track off your Video tapes. Ideal for putting a live concert on a CDR !
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