2014年9月29日星期一

RIAA curve (曲線) ....音樂在聽RIAA是啥!

Recording 是指現場錄音麥克風收錄的音壓曲線.
1khz 以下很差大致是錄音麥克風低頻響應靈敏度差也就是性能差之故.
再此意指播放還原音壓低頻響應曲線要拉高之故.

Reproduce (也就是 playback curves)是指播放音樂時 LP放大器, 前極, 後極, 分音器, 喇叭 ....還原音壓曲線(profile)的總和. 


2014年9月25日星期四

Magic 2 MONO equalizer design ---這DIY怎校驗ㄚ?

 LP playback curves equalizer  AKEQ-2 mono
Tube in shielding case.

LP playback curves equalizer  AKEQ-2 mono
Front view.

LP playback curves equalizer  AKEQ-2 mono
front panel


below only ....WiKi explain what's FFRR78

78rpm playback curves

Usage


These EQ curves are presented as a table of "Bass Turnover Frequencies" and "10 kHz Gain Rolloffs". EQ Curves for Audacity can be generated from these Frequency and Rolloff values using the experimental Nyquist plug-in "78 RPM EQ Curve Generator". This plug-in is obtainable from the top of this Forum topic and requires Audacity 1.3.13 or laterPlease give feedback on this plug-in, or ask for help if you need it, by replying to that Forum topic.

  1. Extract 78EQCurveGen.ny from the zip file downloaded from the above Forum topic.
  2. Place 78EQCurveGen.ny in the "Plug-ins" folder inside the Audacity installation folder, then launch or restart Audacity. For more help installing the .ny file to the correct location, click here.
  3. Click Generate > 78 RPM EQ Curve. You can find help inside the plug-in by choosing one of the Help options in "Select Function or Help".
  4. Choose the curve you want from the list below.
  5. Enter the values for your chosen curve for
    • "Bass Turnover Frequency (Hz)"
    • "10 kHz Gain Rolloff (dB)"
    • "LF Shelving Frequency (Hz)" (if a value is given)
    in the equivalent boxes in the plug-in dialogue.
  6. Click "OK" in the plug-in to save the .xml file to your chosen location.
  7. Select some audio and choose Effect > Equalization.
  8. Choose "Save/Manage Curves...".
  9. Choose "Import...", navigate to the location where you saved the .xml file from 78EQCurveGen.ny, then "Open".
  10. Click "OK".




Now ...Equalization (EQ) Curves Explained


When phonograph records are made, the sound being recorded is deliberately distorted by reducing the volume of the low frequencies and increasing the volume of the high frequencies. This process, known as 'pre-emphasis', allows the low frequencies to be accommodated in the limitations of the record groove and reduces the effect of high frequency surface noise. If pre-emphasis was not carried out, the bass notes in the music would create a groove in the record that oscillated so wildly that the stylus could jump out of it on playback, and the treble notes would be drowned out by the surface noise of the stylus in the groove.
On playback, the pre-emphasis must be reversed in order to restore the original sound. This is known as 'de-emphasis' or equalization (EQ).
Modern vinyl records use a method of pre-emphasis and de-emphasis adopted by the Record Industry Association of America (RIAA) in the 1950's, and the EQ curve used is known as the RIAA curve. However, before the RIAA curve was adopted, each record label used its own EQ curve for recording and, for these records (78rpm and early vinyl), the correct EQ curve must be used for playback.
Each 78rpm EQ curve is a combination of two filter characteristics; a bass boost curve, defined by a 'Bass Turnover' (or 3dB) frequency, and a treble cut curve, defined by a '10 kHz Gain Rolloff' parameter, i.e. a defined level of treble cut at 10 kHz.
As an example, Figure 1 below shows the characteristic of the bass boost curve defined by a 500Hz Bass Turnover, and Figure 2 shows the characteristic of the treble cut curve defined by a 10 kHz Gain Rolloff of -13.7dB. These two curves, when combined, give the characteristic shown in Figure 3.




The EQ curve may also include a Low Frequency Shelving filter, (although it is absent from the definition of most 78 rpm EQ curves). This addition reduces the effect of the bass boost at very low frequencies (typically 50 or 100 Hz) in order to attenuate low-frequency noise such as turntable rumble. Figure 4 shows the effect of a 50 Hz LF shelving filter being added to the curve in Figure 3. This is in fact the RIAA standard EQ curve.

EQ Curve List

Table 1: 78rpm Playback Equalisation Curves
LabelSeriesBass Turnover
Frequency (Hz)
10 kHz Gain
Rolloff (dB)
LF Shelving
Frequency (Hz)
Source
Acoustic Recording
(such as cylinders, etc..)
0 (or as required)0 (or as required)1
AESstandard400-121
AFRS Transcriptions5000 or -51
Allegro750-161
Allied500-161
American Recording Society500-12 or –13.71
Angel500-121
Arizona400-121
Artist500-161
Atlantic500-161
Audiophile300-81
BBC Transcriptions1949500-51
BBC Transcriptionsmost250-3000 to -51
Bach Guild501-529500-750-161
Banneradjust as required500-161
Bartok629-161
Bartok301-304, 309, 906-920700-161
Berlinerspeed = 71.29 RPM001
Blue Bird800-101
Blue Note Jazz400-121
Blumlein2500502
BostonCOL*-161
Brunswickrare1000-8.51
Brunswickfrom 1946300-161
Brunswickearly300-5000 or -161
Brunswick50003
BSI 78353-10.550 [2]1, 2
Caedmon629-111
Caedmon1001-1022700-121
Cameoinconsistent, adjust as required1
Canyon400-121
CapitolFDS400-121
Capitol-Telefunken50001
Capitol500-121
Capitol1942400-123
Cetra Soria400-12 or -161
Cetra400-111
Coliseum400-121
Columbia*1925200-71, 3
Columbia*1926250-51
Columbia*1938-most300-161, 3
Columbia*variousCOL*-161
Columbia*European300-51
ColumbiaEnglish25003
Concert Hall400-121
Contemporary400-111
Cook Laboratories500-111
Cook Laboratoriesbinaural inside band50001
Coral400 or 750-12 or -161
Deccaearly150 or 3000 or -61
Decca 78150-92
Decca1946-400 or 500-121
Decca FFRR1949250-51, 3
Decca FFRR1951300-141
Decca1934400-123
Deutsche-Grammophone300-51
Dial500 or 750-161
Disc300-161
Ducretet-Thomson450-111
EMI193125001, 3
EMI33 LP500-121
EMS375-121
Edison001
Electrola800-101
Elektra629-161
Epicthru 1954COL* or 750-161
Esoteric400 or 500-121
European28001
Festival750-161
FFRR 78300-5402
Folkways629-161
Good Time Jazz400-121
Gramophone300-101
HMV1925-194625001, 3
HMV1946400-101
HMV1946-1954500 or 800-161
HMVAmerican400-121
Handel Society750-16 or -171
Haydn Society750-16 or -171
Harmony Acousticsthru 8/29300-161
Hit of the Week500-51
Kapp700-161
Kendall629-161
King500-161
Linguaphone30001
L’Oiseau-Lyre500-101
Londonearly30001
Londonup to LL846500 or 750-10.51
London FFRR1949-250 or 280-51
London FFRR1949250-53
Lyrichordearly400 or COL*-161
Lyrichordnewer629-161
Mercurythru 10/54400-121, 3
MGM5000 or -121
MGM500-123
Montilla500-121
Musicraft750-141
NABstandard500-161
New Records750-161
Nocturne400-121
OceanicCOL* or 750-161
Odeonearly electricals70001
Odeonpre-1947300-8.51
Oiseau-Lyrethru 1954COL*-8.51
Okehelectricals3000 or -8.51
Orioleinconsistent, adjust as required1
Orthoacoustic Transcriptions500-161
Overtone400 or 500-161
Oxford750-161
Pacific Jazz400-121
Parlophonevaries with era300 or 5000 or –8.51
Parlophone50003
Patheinconsistent, adjust as required1
Period500-161
Polydor300-8.51
Philharmonia400-121
Polymusic500-161
Polymusicbinaural inside band50001
RCA Victorearly acoustics 71.29 RPM001
RCA Victorlater acoustics 76.59 RPM001
RCA Victor1925 78 RPM250 or 3000 or -51
RCA Victor1931 LP only700 or 8000 to –10.51
RCA Victor1933375-8.51
RCA Victor1935300 or 50001
RCA Victor1938500-51
RCA Victor1938 – 19485000 to -121
RCA Victor1938 – 1947500-73
RCA Victor1948500-10.51
RCA Victor1949-500-12 or -131
RCA Victor1947 - 1952500-123
Rachmaninoff Society750-161
Radiofunken40001
Remington500-161
Renaissance750-121
RIAAstandard500-13.7501
Riverside400-121
Romeoinconsistent, adjust as required1
Schirmer1000-241
Stradivari750-161
Supraphone40001
Technicord800-121
Telefunken40001
Transcriptionsvarious, typical500-161
Ultraphone40001
UraniamostCOL* or 750-161
Uranianewer400-121
Vanguard411-22, 6000-18,
7001-7011, 8000-8004
COL* or 750-161
Velvet Toneacoustics to 8/29300-161
Victor1925 (see RCA Victor for 1929-)200 to 500-73
Vitaphone950-18.51
Vitaphonemotion picture30001
Vocalionelectricals30001
VOX500 or 750-161
War Department12” Special Services700-51
Western Electricearly transcriptions30001
Westminsterpre-1956500 or 750-161
Westminster“AES” printed on jacket400-121
Westrex20001, 2
Westrex (later)300 or 50002
Zonophoneearly 71.29 RPM001
Zonophonemost30001
  • COL - Some recordings require a Bass Turnover of 300 Hz or 500 Hz, a 10 kHz rolloff of -16 dB and a LF Shelving filter at 100Hz.
This is often referred to as a "Columbia curve".


Table 2: Pre-1955 LP Playback Equalisation Curves

LabelSeriesBass Turnover
Frequency (Hz)
10 kHz Gain
Rolloff (dB)
LF Shelving
Frequency (Hz)
Source
Angel500-123
Audio Fidelity500-163
Bach Guild501-529500-163
Bartok301-304, 309, 906-920629-163
Boston500-163
Caedmon1001-1022629-163
Capitol400-123
Capitol-Cetra400-123
Cetra-Storia(a)500 or (b)400(a)-16 or (b)-123
Colosseum(a)400 or (b)500(a)-12 or (b)-163

2014年9月22日星期一

西電低頻(profile)掉很多...驚艷的很誇張.




1928 Western Electric cinema speaker


2011 High End Show in Munich
WE16A each channel  Mid.WE555x2 Tweeter WE597A x1



Play music ...Max Bruch .... Scottish Fantasia, op.46 ...1.Grave-Adagio cantabile




















K2HD reversion











2014年9月11日星期四

2014年8月18日星期一

G.I.P. 勵磁式號角喇叭

G.I.P Laboratory 是以復刻WE西電-勵磁式號角喇叭的公司,是在日本 YL Acoustics 復刻WE西勵磁式號角喇叭之後才開始全部單體的磁鐵都是勵磁式設計,也就是需要額外供應電源才能產生磁力勵磁喇叭號角另接

8吋全音域喇叭原是以復刻WE755A(鈷磁Alnico)為樣本 ,另補高音GIP-597A


G.I.P Laboratory 三音路設計,高音單體原廠編號是GIP-597A Model 2,它是以W. E.經典的597A高音單體為樣本復刻而成。中音則是GIP-D5015A (原WE594),前方擁有開口頗大的號角 低音單體則是GIP-W4601A,深埋在箱體裡面,以woofer horn 設計是所謂低音號角。箱體採用美松夾板製成,兩側金屬方形外殼是額外供應電源才能產生磁力勵磁式喇叭電源,採定電壓定電流源設計


這是分音器,金屬方形外殼的是電容,是油質電容,兩側木板(線軸)中復刻古時的電感,無電阻。全部以搭棚製作,紅色線材是WE的布線。

2014年7月20日星期日

走過咖啡店早年歲月

咖啡店從無到有... 從有到無... 歲月的流逝 ,剩下的祇有記憶.

從無到有--- 舊店設立.
從有到無--- 拔營....牧咖啡的咖啡人.....移址, 啡客...........的遷徙.

咖啡店=咖啡+音樂

咖啡=日式咖啡+美式咖啡
日式咖啡=日式單品+日式花式咖啡
美式咖啡=美式單品+美式花式咖啡
.........."請不要找茶".

音樂=古典音樂+真空管