What the information means - Images

 

This page has links to images captured from a wav editor. They demonstrate some of the conditions described and terms used in the flaw notes for a recording version. These are just examples. When the conditions are mentioned, they vary in magnitude and style from recording to recording. Some images are in wav view, which shows volume level over a segment of music. Other images are in spectral view, which shows the relative strength of frequencies over a segment of music.

 

• a nice full warm sounding dat recording

 

• a cassette recording. Notice the drop off in frequency above 18k compared to the dat. Above 18k is noise where a dat recording is usually cleaner.

 

• a mini-disk recording. Notice the “lego parapets” which are the castle like parapets or notches carved out of the music. The software used to reduce the file size steps through each increment and decides whether to remove everything above a given frequency. So at one increment it may remove everything above 16k and the next remove everything above 17k and then back to 16k. This leaves the “lego parapets’ or notches. The result is a less full or hollow sound when compared to the original dat if one exists.

 

• floating parapets. This is another method sometimes used to carve up the music to save disk space like with mini-disk or mp3 or internet streaming audio.

 

• 32k dat. These have nothing above 16k and do not have lego parapets.  Recording at 32k allows for twice as much music on a dat. The result is a less full sound when compared to the original 44k or 48k dat if one exists.

 

• Digital clipping. The tops of the wavs are just cut off horizontally. This happens when on a digital recorder the levels are set too high and go over the maximum of -0db. It also happens when someone later amplifies the recording digitally so that the peak that would go above -0db is just cut off. If a lot is cut off, then the sound can get harsher and distorted. It is especially bad when the peaks of the wavs of the vocals are clipped.

 

• Limiting. Either the hardware in the recorder or later applied software is used to avoid digital clipping when the levels would otherwise cause digital clipping. This tends to round out the wav top instead of  just cutting it off with the digital clipping. In the first example the bottom of the wavs are limited to -6db and the tops at -3db in an asymmetric pattern. In this second limiting example the wavs are limited at about -5db and may also include some brickwalling. If a lot is limited, then the sound can get harsher and distorted.

 

• Brickwalling. On this site, this term describes when the volume level of the music is beyond the limit that the hardware (usually a recorder pre-amp) was designed to handle. It becomes unable to pass on an accurate representation of the music and just sort of breaks up the signal. (The term “brickwall” is also used elsewhere to describe clipping and limiting, but on this site it only refers to the above since they have their own terms.) Limiting and clipping are a distortion caused on the peak of the wav by flattening it. Brickwalling may also have the peaks flattened but also has the flattening of the sides of the wavs as the hardware loses its ability to capture the music’s detail. In wav view one sees a diagonal or slightly curved line between peaks where detail is missing. The first brickwall example shows curved lines connecting the peaks while a second brickwall example and third brickwall example show more diagonal lines between the peaks. If a lot is brickwalled, then the sound can get harsher and distorted.

 

• Compression. This shows heavy compression of a recording and then the original recording. Much of the dynamic range has been removed and the recording was made louder and harsher. This is before the heavy compression.

 

• Digi-pops. These are a misplaced sample that can be heard as a pop. These happen generally in transfers that did not go right. Usually from a bad cdr rip.

 

• Discontinuity pop. Happens in a bad transfer where some samples are lost. Usually from a bad cdr rip.

 

• Square wav static. This happens when a dat has errors on playback. Sometimes if it is noticed, it may play correctly on a subsequent try.

 

• Digital Drops. These are horizontal lines in wav view. These happen generally in transfers that did not go right. Usually from a bad cdr rip. An analog drop is similar but because there is more noise in analog the drop is more curved and fuzzy.

 

• Between track gap. Usually caused by poor methods copying cdr to cdr and not correcting for sector boundary errors.

 

• Mic Hit. Sometimes caused by the mic or cable getting moved or brushed while recording. They usually sound like a thump.

 

• TV band. When an analog signal is recorded near a tv or computer monitor, the cathode ray tube sends out a frequency near 16k that gets recorded. This forms a band of varying density when viewed in spectral view. These cannot be heard by most people.

 

• High end streaking. This refers to in spectral view that the spectral density just streaks upward to the limit at 22k. It also looks noisy and usually one can hear more hiss. It is usually caused by a transfer of a dat through a non-professional quality soundcard. Here is a later transfer of the same dat through a professional soundcard without the high end streaking.

 

 

 

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