romikgosai/squad_modified huggingface dataset:
The mid-1970s saw the introduction of dbx-encoded records, again for the audiophile niche market. These were completely incompatible with standard record playback preamplifiers, relying on the dbx compandor encoding/decoding scheme to greatly increase dynamic range (dbx encoded disks were recorded with the dynamic range compressed by a factor of two in dB: quiet sounds were meant to be played back at low gain and loud sounds were meant to be played back at high gain, via automatic gain control in the playback equipment; this reduced the effect of surface noise on quiet passages). A similar and very short-lived scheme involved using the CBS-developed "CX" noise reduction encoding/decoding scheme.

Questions and answers:
['
Q: What was required for quality playback of DBX recordings?
A: automatic gain control', '
Q: When were DBX recordings released?
A: mid-1970s', '
Q: How compatible were DBX encoded recordings with prior technologies?
A: completely incompatible with', '
Q: What was the intention of DBX encoded recordings?
A: reduced the effect of surface noise on quiet passages', '
Q: What did CBS develop in order to reduce outside noise?
A: "CX" noise reduction']
ELPJ, a Japanese-based company, sells a laser turntable that uses a laser to read vinyl discs optically, without physical contact. The laser turntable eliminates record wear and the possibility of accidental scratches, which degrade the sound, but its expense limits use primarily to digital archiving of analog records, and the laser does not play back colored vinyl or picture discs. Various other laser-based turntables were tried during the 1990s, but while a laser reads the groove very accurately, since it does not touch the record, the dust that vinyl attracts due to static electric charge is not mechanically pushed out of the groove, worsening sound quality in casual use compared to conventional stylus playback.

Questions and answers:
['
Q: What company out of Japan offered laser turntables that read vinyl discs optically?
A: ELPJ', '
Q: What was a benedit of laser read discs?
A: eliminates record wear', '
Q: What was a drawback of laser read discs?
A: degrade the sound', '
Q: What was the primary use of laser read discs?
A: archiving of analog records', '
Q: What was a major issue for laser read discs?
A: dust']
In some ways similar to the laser turntable is the IRENE scanning machine for disc records, which images with microphotography in two dimensions, invented by a team of physicists at Lawrence Berkeley Laboratories. IRENE will retrieve the information from a laterally modulated monaural grooved sound source without touching the medium itself, but cannot read vertically modulated information. This excludes grooved recordings such as cylinders and some radio transcriptions that feature a hill-and-dale format of recording, and stereophonic or quadraphonic grooved recordings, which utilize a combination of the two as well as supersonic encoding for quadraphonic.

Questions and answers:
['
Q: Who is Irene?
A: scanning machine for disc records', '
Q: Where was IRENE developed?
A: Lawrence Berkeley Laboratories', '
Q: What is the primary use of IRENE?
A: retrieve the information', '
Q: Can IRENE read vertically modulated information?
A: cannot read vertically modulated information', '
Q: Does IRENE require the  ability to touch the media?
A: without touching the medium']
Terms such as "long-play" (LP) and "extended-play" (EP) describe multi-track records that play much longer than the single-item-per-side records, which typically do not go much past four minutes per side. An LP can play for up to 30 minutes per side, though most played for about 22 minutes per side, bringing the total playing time of a typical LP recording to about forty-five minutes. Many pre-1952 LPs, however, played for about 15 minutes per side. The 7-inch 45 rpm format normally contains one item per side but a 7-inch EP could achieve recording times of 10 to 15 minutes at the expense of attenuating and compressing the sound to reduce the width required by the groove. EP discs were generally used to make available tracks not on singles including tracks on LPs albums in a smaller, less expensive format for those who had only 45 rpm players. The large center hole on 7-inch 45 rpm records allows for easier handling by jukebox mechanisms. The term "album", originally used to mean a "book" with liner notes, holding several 78 rpm records each in its own "page" or sleeve, no longer has any relation to the physical format: a single LP record, or nowadays more typically a compact disc.

Questions and answers:
['
Q: What terms are used for recording with more than one track?
A: long-play" (LP) and "extended-play" (EP', '
Q: What is a typical max playing time of an LP?
A: forty-five minutes', '
Q: Which format is cheaper, LP or EP?
A: LPs', '
Q: Which format held recordings ranging from 10 to 15 minutes?
A: 7-inch EP', '
Q: What was a normal play time per side for LPs?
A: 22 minutes']
In March 1949, as RCA released the 45, Columbia released several hundred 7 inch 33 1/3 rpm small spindle hole singles. This format was soon dropped as it became clear that the RCA 45 was the single of choice and the Columbia 12 inch LP would be the 'album' of choice. The first release of the 45 came in seven colors: black 47-xxxx popular series, yellow 47-xxxx juvenile series, green (teal) 48-xxxx country series, deep red 49-xxxx classical series, bright red (cerise) 50-xxxx blues/spiritual series, light blue 51-xxxx international series, dark blue 52-xxxx light classics. All colors were soon dropped in favor of black because of production problems. However, yellow and deep red were continued until about 1952. The first 45 rpm record created for sale was "PeeWee the Piccolo" RCA 47-0147 pressed in yellow translucent vinyl at the Sherman Avenue plant, Indianapolis Dec. 7, 1948, R.O. Price, plant manager.

Questions and answers:
['
Q: Which colors of 45 were available as late as 1952 before being discontinued?
A: yellow and deep red', '
Q: PeeWee the Piccolo was what?
A: The first 45 rpm record created for sale', '
Q: What significance does Dec 7/ 1948 hold?
A: The first 45 rpm record created for sale', '
Q: How many colors were 45s available in when first released?
A: seven colors', '
Q: When did RCA release the 45?
A: March 1949']
The normal commercial disc is engraved with two sound-bearing concentric spiral grooves, one on each side, running from the outside edge towards the center. The last part of the spiral meets an earlier part to form a circle. The sound is encoded by fine variations in the edges of the groove that cause a stylus (needle) placed in it to vibrate at acoustic frequencies when the disc is rotated at the correct speed. Generally, the outer and inner parts of the groove bear no intended sound (an exception is Split Enz's Mental Notes).

Questions and answers:
['
Q: In which direction does the groove in a normal disc run?
A: outside edge towards the center', '
Q: How is sound encoded on a commercial disc?
A: by fine variations', '
Q: Does it matter at which speed a disc is spun?
A: correct speed', '
Q: Do all grooves bear data?
A: no']
Towards the center, at the end of the groove, there is another wide-pitched section known as the lead-out. At the very end of this section the groove joins itself to form a complete circle, called the lock groove; when the stylus reaches this point, it circles repeatedly until lifted from the record. On some recordings (for example Sgt. Pepper's Lonely Hearts Club Band by The Beatles, Super Trouper by Abba and Atom Heart Mother by Pink Floyd), the sound continues on the lock groove, which gives a strange repeating effect. Automatic turntables rely on the position or angular velocity of the arm, as it reaches the wider spacing in the groove, to trigger a mechanism that lifts the arm off the record. Precisely because of this mechanism, most automatic turntables are incapable of playing any audio in the lock groove, since they will lift the arm before it reaches that groove.

Questions and answers:
["
Q: What is a 'lead out'?
A: wide-pitched section", '
Q: What is the center where the data joins to complete a circle?
A: lock groove', '
Q: Do turntables play music on lock grooves?
A: most automatic turntables are incapable', '
Q: What do most automatic turn tables do when they meet a lock groove?
A: lift the arm', '
Q: Where do you find a lead out?
A: Towards the center, at the end of the groove']
When auto-changing turntables were commonplace, records were typically pressed with a raised (or ridged) outer edge and a raised label area, allowing records to be stacked onto each other without the delicate grooves coming into contact, reducing the risk of damage. Auto-changers included a mechanism to support a stack of several records above the turntable itself, dropping them one at a time onto the active turntable to be played in order. Many longer sound recordings, such as complete operas, were interleaved across several 10-inch or 12-inch discs for use with auto-changing mechanisms, so that the first disk of a three-disk recording would carry sides 1 and 6 of the program, while the second disk would carry sides 2 and 5, and the third, sides 3 and 4, allowing sides 1, 2, and 3 to be played automatically; then the whole stack reversed to play sides 4, 5, and 6.

Questions and answers:
['
Q: Where were records made with raised label areas?
A: reducing the risk of damage', '
Q: Are longer recordings, as found in operas, made for use with auto-changing systems?
A: interleaved across several 10-inch or 12-inch discs for use with auto-changing mechanisms', '
Q: Do grooves on records touch when stacked?
A: allowing records to be stacked onto each other without the delicate grooves coming into contact', '
Q: Do records touch when in auto changers?
A: Auto-changers included a mechanism to support a stack']
New or "virgin" heavy/heavyweight (180–220 g) vinyl is commonly used for modern audiophile vinyl releases in all genres. Many collectors prefer to have heavyweight vinyl albums, which have been reported to have better sound than normal vinyl because of their higher tolerance against deformation caused by normal play. 180 g vinyl is more expensive to produce only because it uses more vinyl. Manufacturing processes are identical regardless of weight. In fact, pressing lightweight records requires more care. An exception is the propensity of 200 g pressings to be slightly more prone to non-fill, when the vinyl biscuit does not sufficiently fill a deep groove during pressing (percussion or vocal amplitude changes are the usual locations of these artifacts). This flaw causes a grinding or scratching sound at the non-fill point.

Questions and answers:
['
Q: What is the most used material for modern audiophile vinyl releases?
A: New or "virgin" heavy/heavyweight (180–220 g) vinyl', '
Q: What is the material preference of collectors?
A: heavyweight vinyl', '
Q: How does the manufacturing process differ between heavyweight and normal vinyl?
A: Manufacturing processes are identical', '
Q: Would would a non filled area in a vinyl press cause when listening to a record?
A: grinding or scratching sound', '
Q: Which pressing of vinyl require more attention to detail, lightweight or heavyweight?
A: lightweight records requires more care']
The "orange peel" effect on vinyl records is caused by worn molds. Rather than having the proper mirror-like finish, the surface of the record will have a texture that looks like orange peel. This introduces noise into the record, particularly in the lower frequency range. With direct metal mastering (DMM), the master disc is cut on a copper-coated disc, which can also have a minor "orange peel" effect on the disc itself. As this "orange peel" originates in the master rather than being introduced in the pressing stage, there is no ill effect as there is no physical distortion of the groove.

Questions and answers:
['
Q: What is an effect of using worn molds when casting records?
A: The "orange peel" effect', '
Q: What is the expected finish of a vinyl record?
A: mirror-like', '
Q: On what frequencies is an orange peel effect most noticeable?
A: lower frequency range', '
Q: What is the effect on a copy if a master as an orange peel effect?
A: there is no ill effect', '
Q: What material is on a direct metal mastering disc?
A: copper']
Breakage was very common in the shellac era. In the 1934 John O'Hara novel, Appointment in Samarra, the protagonist "broke one of his most favorites, Whiteman's Lady of the Evening ... He wanted to cry but could not." A poignant moment in J. D. Salinger's 1951 novel The Catcher in the Rye occurs after the adolescent protagonist buys a record for his younger sister but drops it and "it broke into pieces ... I damn-near cried, it made me feel so terrible." A sequence where a school teacher's collection of 78 rpm jazz records is smashed by a group of rebellious students is a key moment in the film Blackboard Jungle.

Questions and answers:
['
Q: What was a known issue of using shellac to make records?
A: Breakage was very common', '
Q: In which novel does \'Whiteman\'s Lady of the Evening" record get broken?
A: John O\'Hara novel, Appointment in Samarra', "
Q: In Blackboard Jungle what record breaking mention is made?
A: teacher's collection of 78 rpm jazz records is smashed"]
Vinyl records do not break easily, but the soft material is easily scratched. Vinyl readily acquires a static charge, attracting dust that is difficult to remove completely. Dust and scratches cause audio clicks and pops. In extreme cases, they can cause the needle to skip over a series of grooves, or worse yet, cause the needle to skip backwards, creating a "locked groove" that repeats over and over. This is the origin of the phrase "like a broken record" or "like a scratched record", which is often used to describe a person or thing that continually repeats itself. Locked grooves are not uncommon and were even heard occasionally in radio broadcasts.

Questions and answers:
['
Q: What causes clicks and pops on vinyl records?
A: Dust and scratches', '
Q: What is the cause of lock grooves on vinyl records?
A: Dust and scratches', '
Q: Where does the saying "Like a broken record" originate?
A: locked groove', '
Q: How easily do vinyl records break?
A: Vinyl records do not break easily', '
Q: What is a common damage to vinyl records?
A: easily scratched.']
Vinyl records can be warped by heat, improper storage, exposure to sunlight, or manufacturing defects such as excessively tight plastic shrinkwrap on the album cover. A small degree of warp was common, and allowing for it was part of the art of turntable and tonearm design. "wow" (once-per-revolution pitch variation) could result from warp, or from a spindle hole that was not precisely centered. Standard practice for LPs was to place the LP in a paper or plastic inner cover. This, if placed within the outer cardboard cover so that the opening was entirely within the outer cover, was said to reduce ingress of dust onto the record surface. Singles, with rare exceptions, had simple paper covers with no inner cover.

Questions and answers:
['
Q: What causes warping in vinyl records?
A: heat, improper storage, exposure to sunlight, or manufacturing defects', '
Q: What is a cause of once per revolution pitch variation?
A: warp, or from a spindle hole that was not precisely centered', '
Q: What method was used to protect a vinyl record?
A: place the LP in a paper or plastic inner cover', '
Q: What were often found with a paper outter cover and no inner cover?
A: Singles', '
Q: What happens if a vinyl comes with a bit of warp?
A: A small degree of warp was common,']
A further limitation of the gramophone record is that fidelity steadily declines as playback progresses; there is more vinyl per second available for fine reproduction of high frequencies at the large-diameter beginning of the groove than exist at the smaller-diameters close to the end of the side. At the start of a groove on an LP there are 510 mm of vinyl per second traveling past the stylus while the ending of the groove gives 200–210 mm of vinyl per second — less than half the linear resolution. Distortion towards the end of the side is likely to become more apparent as record wear increases.*

Questions and answers:
['
Q: When is distortion most common on a gramophone record?
A: Distortion towards the end of the side', '
Q: What happens as a record wears?
A: Distortion', '
Q: What is a drawback of using gramophones?
A: fidelity steadily declines as playback progresses', '
Q: How much vinyl can be found at the start of an LP?
A: 510 mm', '
Q: Where can you find only 200-210mm of vinyl?
A: ending of the groove']
Tonearm skating forces and other perturbations are also picked up by the stylus. This is a form of frequency multiplexing as the control signal (restoring force) used to keep the stylus in the groove is carried by the same mechanism as the sound itself. Subsonic frequencies below about 20 Hz in the audio signal are dominated by tracking effects, which is one form of unwanted rumble ("tracking noise") and merges with audible frequencies in the deep bass range up to about 100 Hz. High fidelity sound equipment can reproduce tracking noise and rumble. During a quiet passage, woofer speaker cones can sometimes be seen to vibrate with the subsonic tracking of the stylus, at frequencies as low as just above 0.5 Hz (the frequency at which a 33 1⁄3 rpm record turns on the turntable; 5⁄9 Hz exactly on an ideal turntable). Another reason for very low frequency material can be a warped disk: its undulations produce frequencies of only a few hertz and present day amplifiers have large power bandwidths. For this reason, many stereo receivers contained a switchable subsonic filter. Some subsonic content is directly out of phase in each channel. If played back on a mono subwoofer system, the noise will cancel, significantly reducing the amount of rumble that is reproduced.

Questions and answers:
['
Q: What would be a cause of low frequency sounds when listening?
A: warped disk', '
Q: What is a feature many stereos contain to fight back against unwanted noises?
A: subsonic filter', '
Q: What is a sounds commonly heard when listening to a vinyl that is unintentional.
A: Tonearm skating', '
Q: Which frequencies are you most likely to hear tonearm skating?
A: frequencies below about 20 Hz', '
Q: Are there any visual signs of tracking when listening to a record?
A: cones can sometimes be seen to vibrate with the subsonic tracking']
Due to recording mastering and manufacturing limitations, both high and low frequencies were removed from the first recorded signals by various formulae. With low frequencies, the stylus must swing a long way from side to side, requiring the groove to be wide, taking up more space and limiting the playing time of the record. At high frequencies, hiss, pops, and ticks are significant. These problems can be reduced by using equalization to an agreed standard. During recording the amplitude of low frequencies is reduced, thus reducing the groove width required, and the amplitude at high frequencies is increased. The playback equipment boosts bass and cuts treble so as to restore the tonal balance in the original signal; this also reduces the high frequency noise. Thus more music will fit on the record, and noise is reduced.

Questions and answers:
['
Q: What is a limitation of low frequency recordings?
A: limiting the playing time', '
Q: What kinds of unwanted sounds are often heard at high frequencies?
A: hiss, pops, and ticks', '
Q: What is done during recordings to help reduce unwanted sounds?
A: amplitude of low frequencies is reduced', '
Q: What is a benefit of using equalization devices?
A: problems can be reduced', '
Q: What is done to high frequency  sounds to lessen sound issues?
A: amplitude at high frequencies is increased']
In 1926 Joseph P. Maxwell and Henry C. Harrison from Bell Telephone Laboratories disclosed that the recording pattern of the Western Electric "rubber line" magnetic disc cutter had a constant velocity characteristic. This meant that as frequency increased in the treble, recording amplitude decreased. Conversely, in the bass as frequency decreased, recording amplitude increased. Therefore, it was necessary to attenuate the bass frequencies below about 250 Hz, the bass turnover point, in the amplified microphone signal fed to the recording head. Otherwise, bass modulation became excessive and overcutting took place into the next record groove. When played back electrically with a magnetic pickup having a smooth response in the bass region, a complementary boost in amplitude at the bass turnover point was necessary. G. H. Miller in 1934 reported that when complementary boost at the turnover point was used in radio broadcasts of records, the reproduction was more realistic and many of the musical instruments stood out in their true form.

Questions and answers:
['
Q: Whom found that they can make musical instruments sound more natural with an amplifier boost at the turnover point?
A: G. H. Miller', '
Q: What is found when a complementary boost is used at the bass turnover point?
A: reproduction was more realistic', '
Q: When frequency in the treble increases what happens to the recording amplitude?
A: recording amplitude decreased', '
Q: What happens when frequency decreases in the bass?
A: recording amplitude increased']
West in 1930 and later P. G. A. H. Voigt (1940) showed that the early Wente-style condenser microphones contributed to a 4 to 6 dB midrange brilliance or pre-emphasis in the recording chain. This meant that the electrical recording characteristics of Western Electric licensees such as Columbia Records and Victor Talking Machine Company in the 1925 era had a higher amplitude in the midrange region. Brilliance such as this compensated for dullness in many early magnetic pickups having drooping midrange and treble response. As a result, this practice was the empirical beginning of using pre-emphasis above 1,000 Hz in 78 rpm and 33 1⁄3 rpm records.

Questions and answers:
['
Q: Whom found Wente-style condenser microphones helpful?
A: P. G. A. H. Voigt', '
Q: How were Wente-Style condenser microphones helpful?
A: pre-emphasis in the recording', '
Q: When was a pre-emphasis most useful?
A: above 1,000 Hz', '
Q: On which recording types were pre-emphasis used most in the 1920s?
A: 78 rpm and 33 1⁄3 rpm', '
Q: In which Era was this finding most significant?
A: 1925 era']
Over the years a variety of record equalization practices emerged and there was no industry standard. For example, in Europe recordings for years required playback with a bass turnover setting of 250–300 Hz and a treble roll-off at 10,000 Hz ranging from 0 to −5 dB or more. In the US there were more varied practices and a tendency to use higher bass turnover frequencies such as 500 Hz as well as a greater treble rolloff like −8.5 dB and even more to record generally higher modulation levels on the record.

Questions and answers:
['
Q: What was the industry standard in Europe for record equalization?
A: there was no industry standard', '
Q: In which country was the treble roll off greater?
A: US', '
Q: Which country prefers a bass turnover setting of 250-300 Hz?
A: Europe', '
Q: What was the industry standard on equalization practices?
A: there was no industry standard', '
Q: Which country used the most varied equalization practices?
A: US']
Evidence from the early technical literature concerning electrical recording suggests that it wasn't until the 1942–1949 period that there were serious efforts to standardize recording characteristics within an industry. Heretofore, electrical recording technology from company to company was considered a proprietary art all the way back to the 1925 Western Electric licensed method used by Columbia and Victor. For example, what Brunswick-Balke-Collender (Brunswick Corporation) did was different from the practices of Victor.

Questions and answers:
['
Q: How far back did records show the art of sound recordings?
A: 1925', '
Q: How was standardization prior to 1942?
A: considered a proprietary art', '
Q: Around what time period was there an attempt made to standardize recordings?
A: 1942–1949']