Este assunto está definitivamente bem explicado noutro blog meu, mais específico e sem necessidade de buscar sites em inglês: O blog é o http://sonsultrassonicosnovinil.blogspot.com onde é demonstrado que o Vinil atinge normalmente de 7 hz (média) até 48 kHz, e com freqüências esporádicas ultrassônicas denominadas transientes até 100 kHz, mais ou menos, não há como "fincar" medida exata, podem estes transientes terem 99.056 kHz ou 102 kHz. Para termos de comparação, o melhor disco digital não passa de 48 kHz (SACD, Blue-ray e DVD-A, etc.). E o CD, não passa de 20.050 Khz. Em mídias digitais, vale dizer, CD, DVD-A, o corte é abrupto em 20.050 kHz para o CD e 48 kHz para as mídias de sofware - DVD-A, SACD, etc.
E não dizem que o Vinil tem um "ruído de fundo", que prejudica? Estalinhos esporádicos, mesmo num vinil bem conservado? Leiguice. O Vinil, de 7 hz até 500 hertz tem uma relação ruído inferior a do CD, que é de - 88dB SPL, mas cujos graves mais encorpados superam e fazem sumir logo quando começa a música. E a partir dos 500 hertz do espectro sonoro, eles SUPERAM qualquer mídia digital com o alcance da relação sinal-ruído em - 96 dB SPL (SPL = Sound Pressure Level ou nível de pressão sonora) e com a banda frequencial total espetacular de 100 kHz levando em conta os transientes ditos "exagerados" pela australiana, Doutora em Ciências da Computação, Christine Tham. Vejam gráficos belíssimos e vídeos do You Tube demonstrando isso no blog acima mencionado, o http://sonsultrassonicosnovinil.blogspot.com onde a questão é muito bem fechada.
Pessoal, a bem da verdade escamoteada por certos engenheiros. Este texto prova como eu estava certo e certos inescrupulosos ficam espalhando "engenheirês" falso para confundir quem não é da área e escamotear ou esconder a verdade.
Leia o comentário do especialista em gravações e mixagens digitais CLÁUDIO HENRIQUE PICOLO, com tarja em amarelo, logo após o texto em inglês.
Segue o anexo original. O PDF. está à disposição de quem quiser. E-mail:
Leitores, o texto abaixo está cheio de erros de digitação feitos pelo digitalizador do livro (Página 30), erros que são distâncias incorretas entre caracteres; vírgulas "coladas"; iniciais sem maíuscula e outros vários erros que quem tem o antigo curso de datilografia (Como eu tenho) e os atuais cursos de digitação em computador - Redação, sabem do que estou falando. Mas isso em nada prejudica a essência do saber contido.
This is a follow-up to the author ’s “LP Transfer to CD,” published in the Oct.’01 issue of aX (Pg.30)—Eds.
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high-resolution audio formats onto DVDs. The secret was to open my AIFF sound files in QuickTime Pro and save them as self- contained movies.I needed to be careful to use BIAS Peak to insert markers at the beginning of each track in a file before making them into movies (.mov files). Because I now had movies with soundtracks but no video tracks,and Toast 6 Titanium was supposed to author DVD videos,I just told it to make a DVD video and use the movie files as content.This it did happily.Each AIFF file be- came a movie title,and I was able to add more than one movie title to a DVD,limited only to the f ree space on the DVD.The markers in a file became access points for starting the movie and for accessing individual audio tracks within the file,such as individual tracks on one side of an LP.Apparently I became the first person to use Toast Titanium to author high-resolution audio onto DVDs.Figure 1 shows a screenshot of the Toast user interface for producing a DVD-Video with the four sides of the 2-LP London album of The Mikado on it.The black rectangles indicate that the file has no video,so that there are no keyf rames to display.Figure 2 shows the window shade that drops down when you click on the “More ” button in the left-hand drawer in Fig.1 .This is where you select the PCM audio format of 96kHz/24 bits in Toast 7 Titanium. At 24-bi t/48kHz resol uti on,the DVDs sounded better than any of my LP to CD trans- fers.I sent the instructions to the website “Ma- cintouch,” and you can find them in the archives at www.macintouch.com/audiorecord5.html . I also burned a DVD with samples of classical and rock music on it and sent it to Adam Fingerman,the Director of Product Develop- ment at Roxio,so that he could hear the differ- ence between this and 16-bit recordings.Their engineering team was totally unaware that Toast could record high-resolution audio,and was not convinced initially that more bits were necessary. But they listened to the DVD and to other users,and eventually they added the ability to author high-resolution audio onto DVDs with the release of Roxio Toast 7 Titanium.Roxio went whole hog and settled on 24-bit/96kHz resolution,calling the discs “Music DVDs.”I burned a few more DVDs by recording at 48kHz and upsampling in software to 96kHz, but curiosity got the better of me and I pur- chased a Mark of the Unicorn “Traveler ” record- ing and playback interface so that I could make true 96kHz transfers with higher-quality A/D conversion.This is not a consumer-priced prod- uct at $849 –$899,but neither is it consumer quality —it is professional grade,and the im- proved quality is worth the money to a serious sound restorer.
At this point I had the Traveler running into the G5 via Firewire,using Apple ’s SoundTrack Pro to control the hardware.The sound files now had the best quality I had obtained so far,and I needed to work out a procedure for cleaning up ticks and making the vinyl sound more present- able in the digital domain. One day the Macintouch website announced new shareware called ClickRepair,written by Dr.Brian Davies,a mathematics professor at the Australian National Universit y in Can- berra.SoundTrack Pro has a nice click removal tool that is pretty much automated,relieving the editor of most tedious waveform repair by hand.It is good but not great software. ClickRepair,on the other hand,can do a really deep cleaning of an LP track —or even a badly damaged shellac 78 track —so that the sound becomes truly beautiful to hear.It does so by changing only those samples that are part of a click,so that the overall f raction of samples modified is ver y small.Unfortunately,it only worked on sample rates up to 48kHz. I bought ClickRepair and fed it some truly difficult files to work its magic on.It stumbled on a few by making unneeded “repairs.” I estab- lished e-mail contact with Brian Davies so that he could work out the deficiencies and I could persuade him to make up the sample rate gap between ClickRepair and Toast 7 Titanium.At one point he had me send a CD with sample AIFF files on it to the Center for Nuclear Re- search and Modeling in Cedex,France,so that it could meet Brian and his colleague there to help them work on the problem of click discrimina- tion during trumpet pieces. Happily,ClickRepair is now a sophisticated and effective program,and it works with 96kHz files.
THE TRANSFER PROCEDURE
What follows is the workflow that I developed using my own software suite for transferring audio f rom vinyl LPs to DVDs.I explain my rationale for the procedure,so if your software differs f rom mine,you can work out a sensible workflow of your own.
FIGURE 1:Toast Titanium for authoring video DVDs with sound only.FIGURE 2:Choosing 4-bit 96kHz linear encoding (PCM)for video DVDs.
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Before you commit your vinyl disks to the digi- tal medium,you should consider measuring the f requency response of your playback chain using a test LP.My collection contains an old Soundcraf tsmen test LP with all pink noise on side B.I have written software for measur- ing pink noise,so I used the PowerMac 8600 to measure the pink noise playback.This test signal is believable only between 100Hz and 10kHz because of the limitations of the General Radio pink noise generator of the time,but that is sufficient.Figure 3 shows the f requency response of SuperFreq,a parametric equalizer in BIAS Peak,when it is set to flatten out a peak in the ratio of the right-channel response divided by the left-channel response (right minus left on a DB scale).I apply this correction only to the left channel of a file to make both channels have identical response.This solidifies the stereo image remarkably,subtle though the correction may be.Figure 4 shows the f requency response of SuperFreq when it is set to equalize out the remaining phono cartridge response error com- mon to both channels.It is applied to both channels in a stereo recording.The result- ing sound is as neutral as a modern movie soundtrack.Note that there are no peaks or dips to be corrected at the RIAA corner f requencies of 500Hz and 2122Hz,indicating a fairly faith- ful RIAA preamplifier.Both of the f requency plots show a dip of 2dB on a scale that is ±18dB.
It doesn ’t do any good to have a perfect RIAA preamplifier if you don ’t also correct for the cartridge ’s f requency response errors,so I recommend finding some way to measure your own setup.Whenever I get a new computer or A/D converter,I check it for polarity inversion at the input with a flashlight battery,or a bat- tery plus a 1:10 attenuator in the case of mike preamp inputs.The PowerMacs 7200,8600,and G5 all invert polarity,so you must correct this during editing.The MOTU Traveler preserves polarity,bless its heart.
The Traveler connects to the PowerMac G5 via a FireWire cable,which also powers the box. I run my turntable and analog electronics f rom a TrippLite LC1200 AC line conditioner to remove AC hash and act as a ground isolater. I clip a ground wire between the phono pre- amp chassis and the PCI card opening area of the G5.This is to eliminate hum f rom ground loops.My old CRT monitor needed its own isolation transformer,but my new LaCie CRT monitor doesn ’t. When you set up SoundTrack Pro for re- cording via FireWire,you can check the record- ing level meter to see whether your background noise is acceptably low.
SET YOUR RECORDING LEVEL
You can find the peak levels by recording sam- ples of the LP during the loudest parts of the music.The meters in SoundTrack Pro are not
100%infallible for this purpose,so you should stop the recording process and examine the waveform in the file to determine the head- room.After fighting to get good sound f rom 16 bits,I am fanatical about achieving only 1 –2dB of headroom in a transfer.I prefer this to leav- ing more headroom and then amplifying the file in the digital domain,because this wastes resolution. When you finish a track,you can review the waveform for clipping.SoundTrack Pro and BIAS Peak can each help you with an automat- ed procedure for this.If I have clipping,I reset the level and re-record.If your phono cartridge has large dips in its response requiring a peaked equalization in sof tware,you might need to leave more headroom than I do.
SAVE YOUR FILE
Apple ’s OS X has a facility called “Core Audio ” that programmers can tap into when producing sound editing programs.One facility that most use is the ability to save a sound file in 32-bit floating-point format.Apple considers this the native format for sound in OS X.I recommend using this format to preserve your sound quality during subsequent processing. Because 32-bit floating-point numbers have a 24-bit f ractional part and an 8-bit exponent part,you might wonder how this can be better than 24-bit integers.By a trick in how f ractional parts are stored in binary form,the f ractional part actually provides 25-bit precision.The extra bit,along with the scaling properties of floating
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point numbers,will preserve your sound quality during editing,and it will be recovered when you finally requantize back to 24-bit integer format using noise-shaped dither,for disk au- thoring.
EDIT YOUR FILE IN SOUNDTRACK PRO
When I use SoundTrack Pro,I always de-click the entire file in STP as a first step.Another operation is to remove the LP ’s lead-in groove and substitute two seconds of silence.To keep the sof tware ’s speed up while de-clicking,I make the click detection threshold about equal to the local signal amplitude;for example,a full-amplitude signal will use a 100%detection threshold.Sometimes STP makes many false positive decisions in large-amplitude sections,so I may skip de-clicking those sections.Figure 5 shows the waveform editing win- dow in SoundTrack Pro,where the music is the beginning of a Vivaldi mandolin concerto. You can zoom in on the time axis to resolve the waveform and enable use of the pencil editing tool.You can also zoom in on the vertical (am- plitude)axis so weak signals will be much larger and easier to touch up accurately.You hope you won ’t need to do very much of this. If a track seems to have a lot of inf rasonic recording lathe rumble in the waveform,I run a “linear phase ” high-pass filter on the file,set for 20Hz most of the time,or for 30Hz if the rum- ble is worrisome.This eliminates woofer cone breathing.This class of filter has a time-sym- metric impulse response ripple,so you would only use it where it will be inconspicuous.It is handy to use on “thumps ” as long as the music has little content at the thump f requencies and you can discriminate between them.
In some cases lathe rumble is intrusive dur- ing low-level music,even after filtering out in- f rasonics.STP has a broadband denoising func- tion that is effective with background noise.You must take a noise sample where there is no sig- nal,and then set the discrimination threshold by listening only to the noise removed.I preserve tape/vinyl hiss with this filter so that its use will not be conspicuous. If you listen to the many pop music selections during a feature film presentation,you will hear some that seem to be devoid of low-level detail. This is a sign that they were restored f rom vinyl instead of tape,and that broadband noise reduc- tion was used too aggressively. Be sure to process your editing actions to flatten the file occasionally,because STP is not 100%stable.When you save the file after edit- ing,it will be ready for attention f rom BIAS Peak.
EDIT YOUR FILE IN BIAS PEAK
The real beauty of BIAS Peak is the SuperFreq equalizer feature pictured in Figs.3 and 4 .As mentioned,I use it religiously to equalize out the phono cartridge imperfections.The main editing window is shown in Fig.6 .Note that the headroom is 2.5dB,as stated in the lower left corner of the screen:“Max –2.5dB,” where the sampling resolution is also given.I added a marker at the head of the file called “Track 01.”If you make Video DVDs as I do,the track markers provide the access points for the tracks in a title.You need at least one marker per title. If you use Roxio ’s Music DVD format instead, then you will use the markers to help you sepa- rate the tracks into individual files in order to produce a track list in Toast. Next,I use the “Gain Envelope ” DSP operation in Peak to produce a two-or three- second fadeout at the end of the LP side.I use exponential decay,applied to the tail of the file where the music has just faded out by itself,and I continue the fadeout into the “silent ” runout groove.This produces a natural-sounding fade to silence.I am not a fan of linear fadeouts. You have the option of adjusting the file ’s amplitude,if you desire to maximize the volume. But you must check the headroom on both sides of the LP before doing this so that you can treat both sides equally.Obviously the same goes for two-LP albums or more. Now you can save the file to preserve your 32-bit master.It takes a short wait for Peak to render the edits and write the new file. To produce a 24-bit file for DVD authoring, choose “Save As ” f rom the File menu,and select the 24-bit depth.Also,you need to turn on dith- ering at this point.I always give a saved file a suggestive name,such as “Vivaldi_Side_01_24_ 96.” Peak will add the .aif filename extension.
DE-CLICK YOUR FILE IN CLICKREPAIR
To avoid contention for resources,quit all other sound-related programs and start up ClickRe- pair.You have the option of listening to just the noise,which is easier if you have an external interface such as the Traveler to boost the weak headphone signal up to audible levels in this situation.You start the click repair and then ad- just the sensitivity,and check for music content being removed which you would rather keep in the file. If you find that ClickRepair has difficulty with certain parts of your file,you can break it up into smaller files and de-click each one sepa- rately.Then you reassemble the files.This would
FIGURE 5:SoundTrack Pro ’s waveform editing window.FIGURE 6:BIAS Peak ’s waveform editing window.
only happen in an extreme case. To be conservative,you can reopen the re- paired file in BIAS Peak and audition it,taking care to turn the headphone volume back down first.Software is not able to detect all vinyl flaws,so this is your chance to find them by listening and correct them with the pencil tool. Peak ’s pencil tool acts like a “healing tool,” in that logic helps blend your correction into the rest of the waveform to avoid audible artifacts. This is much more effective than Peak ’s auto- mated click repair facility. If you now open your file in SoundTrack Pro, modify it and close it,you will lose all of your markers.STP won ’t even save its own markers when you close and reopen a file.
AUTHORING A DVD IN ROXIO ’S TOAST 7 TITANIUM
You have your choice of authoring a Video DVD as I do,or a Music DVD as Roxio sup- ports officially.The window for producing a Music DVD is shown in Fig.7 .This Playlist consists of two songs,each one an entire side of a George Wright LP.If I had broken each side into individual files corresponding to the tracks, there would be many more songs in the Playlist. You may add artwork to take the place of the generic musical note picture in the window.You will see your artwork on the monitor when you play the DVD.In general,I don ’t have a screen connected to my DVD player.I only use it for audio.I use my computer for playing DVDs because of its superior scaling and interpolation algorithms.Once you l earn how to access tracks i n
Apple ’s DVD Player software on your computer, or in your con- sumer DVD pl ayer wi t h a s c r een,you needn ’t bother using the screen after that for your audio-onl y DVDs. I always tell Toast to save the formatted DVD file as a Disk I mage.Thi s way I don ’t need to sacrifice any blank DVD-Rs to find out whether I have made errors in the DVD authoring setup.Toast is not quite a What-You-See-Is-What-You-Get program yet, so you can ’t see how your DVD will look until it. COPYRIGHT INFORMATION - Macintosh, PowerMac, Final Cut Studio, and SoundTrack Pro are registered trademarks of the Apple Computer Corporation. Pro Tools is a registered trademark of the digidesign corporation. Oxford Plugin and PlayStation 3 are registered trademarks of Sony Corporation.SuperFreq.,
BIAS Peak and BIAS Peak LE, are registered trademarks of Berkley Integrated Audio Systems. Toast ,Toast LE, and Easy Media Creator are registered trademarks of Roxio, a division of Sonic Solutions.
Other product names mentioned here in are the property of their respective owners and authors. AIFF: Audio Interchange File Format —An Apple- Developed file format for audio files that are interchangeable between different editing software suites — supported by many software developers. Disk Image:a file on a hard drive that has the same data layout as (for instance)an optical disc to be recorded. DSP: Digital Signal Processing —the method of modifying digital sound data — it ’s all done by multiplying sample values by stored coefficients and summing them into registers. DSP Farm: A PCI card containing many DSP integrated circuits for processing many channels rapidly. Exponential Decay:the decay of the amplitude of a signal,where the percentage reduction in remain ing amplitude is the same for each time interval. Sound in nature decays exponentially. FFT: Fast Fourier Transform — A fast numerical algorithm for expressing a complex wave as a sum of its frequency components — Known among mathematicians as the Tukey-Cooley algorithm. File Flattening: When editing audio or video, this refers to the process of rendering all of the changes stored in an Edit Decision List to permanently modify the content in the audio or video file. FireWire: a cable and transmission protocol that achieves 400 or 800Mb/sec transfer rate, also known as the IEEE 1394 standard. Floating Point:a way of storing numbers in a word of computer memory.The number 1 = 3.1415926 and is written as 0.3141593 × 10 1 in decimal notation.In a binary word,the fractional part (3141593)and the exponent (1)are expressed as binary digits,with 24 bits for the fractional part and 8 bits for the exponent.The leading non-zero binary digit after the decimal point (the “radix ” ina binary word) is always 1,and is not stored.It is always replaced when moving the data to anarithmetic register for a math operation. Keyframe:originally a single frame of animated film artwork that defined the subject ’s motion. It was a complete frame drawn by a senior artist. The frames in between keyframes were drawn by junior artists called “in betweeners ” in an animation studio.In the language of data compression for video,a keyframe is a complete digital representation of a frame that does not rely on information from preceding or following frames. Linear Phase: The characteristic of a filter transfer function where it acts as a pure time delay, or as no delay at all.Otherwise,the delay varies with frequency and the phase is not linear. Marker:a piece of metadata inserted into a sound file that is not included in the sound data itself. It consists of the sample number where it is inserted, plus any text information that the sound editor wants to associate with the marker.Markers are
displayed in the waveform view of a sound editing window,along with the text.The editor uses them
as reminders,as beginning and end points for a selection of sound,and for telling QuickTime Pro
where the chapter markers are in a movie file. PCM: Pulse Code Modulation — refers to the linear
encoding method of digitizing audio,where the spacing between all voltage levels is the same, and
there is no data compression.Also called LPCM for Linear PCM. Polarity:the characteristic of an electronic signal where a positive pressure pulse in a sound wave is represented as a positive voltage in an analog elec-
tronics chain,or as a positive number in a digital system.Most listeners can hear a difference when
the polarity is inverted. QuickTime:Apple ’s software architecture for sound, video, and movies on the Mac and PC platforms. QuickTime Pro: An optional $30 upgrade that adds editing and playback enhancements to Quick- Time.WYSIWYG: "What You See Is What You Get". GLOSSARY OF TERMS. FIGURE 7: Toast Titanium for authoring music DVDs. Six (6) audioXpress 2007 www.audioXpress.com has been authored. After Toast has finished wr iting a Disk Image file of your new DVD onto your hard drive,you can double-click on the file “myfile- name.toast,” and Toast will come to life and mount the image.Then DVD Player will start up and put your nifty interface on the screen. This is where you check that all of your track markers,titles,and artwork are in good shape. When you are satisfied at this point,you can burn a DVD in Toast by copying the Disk Image onto a blank DVD-R.Generally,two vinyl LPs will fit onto one DVD at 24-bit/ 96kHz resolution.Your mileage may vary.You have the option of applying Dolby data com- pression to squeeze more music onto a DVD, but I always opt for linear encoding (PCM)for best sound quality.
POSTLUDE: THE FFT DISPLAY (Fast Fourier Transform display):
To check your file visually for ticks,you can use SoundTrack Pro ’s FFT display,which presents a voiceprint of the music with the time axis running left-to-right,and f requency f rom bot- tom-to-top.Amplitude is represented by the brightness of the virtual oscilloscope display. Apple likes phosphor green,for some reason. A click will be visible as a vertical bright spike in this display because of its extended high-f re- quency response. I found that music with flute soloists,or dominant flute sound,and brass showed promi- nent tick-like artifacts at note changes.Some looked bad enough,or occurred between notes, so that I pencil-edited them out.But it seemed as though transients were a natural part of note changes in these wind instruments. An e-mail to Brian Davies cleared up this issue.He replied that he had spent much time with a James Galway flute recording to make the logic in ClickRe- pair discriminate be- tween vinyl clicks and f l ut e not e changes . Once Click Repairis done with a file, about all you can do is check for pops and thumps,and not for clicks.The real clicks are gone.Figure 8 s hows an FF T di s pl ay of the beginning of the Vivaldi Mand olin concerto, expanded in time so that individual notes are visible.I believe that frequency components much beyond 22.050 kHz are processing artifacts. This file was recorded at a sample rate of 48 "kHz" (A.s).
HIGHER-END HARDWARE AND SOFTWARE
If you have the budget of a feature film pro- duction at your disposal,you can invest in a digidesign Pro Tools setup,consisting of a Pow- erMac G5 or Mac Pro tower containing DSP farm cards and interface cards,plus an external interface,control surface,and the Pro Tools software itself.For LP restoration you will add Sony Oxford plug-ins for equalization and noise removal.Think about spending around $10,000 for this setup. If all you want to do is transfer LPs,and not make feature films,you can purchase the Apo- gee Digital Rosetta 200,a very tasty two-chan- nel A/D-D/A box.You will need to add the FireWire interface card so that you can connect it to your computer.This will run about $2160 at street prices.You may wish to add the Big Ben clock for another $1350 for the ultimate in low recorded sample jitter.Other high-end mastering boxes are in this same price range.
REAL WORLD HARDWARE AND SOFTWARE
According to Tomlinson Holman ’s book,no “24 bit ” A/D converter actually attains full 24-bit resolution,and since he completed his book I think that this is still the case.So if you are shopping for a more mid-priced converter box,you want to read the reviews concerning sound quality rather than con- centrating on the signal-to-noise number. You can find converters in the $200-$900 range with qualit y and versatilit y prett y much proportional to price.
Rod Paine, a stalwart Macintosh user and occasional contributor to Macintouch,found that the E-MU 1820 card met his require- ments for recording at the 192kHz sample rate.But it only works in a PC.So he bought a cheap PC for the purpose of making LP transfers,and he uses Disk-welder Bronze to author DVD Audio disks.He sent me some AIFF files,which sound very nice.I needed to downsample them to 96kHz to play them.DiskWelder Bronze now also runs on the Macintosh platform,and many external converters work at 192kHz. DVD Audio disks require special players, but you can play DVDs authored with Toast Titanium,with only music on them,on any type of DVD player.If you want to go the bargain route,you can use the A/D converter built into your computer in conjunction with shareware to do the editing.Here is a list of appropriate resources that supports vinyl (damage) restoration:
Ray-Gun, for Mac and PC:
Amadeus II for Mac: www.hairersoft.com
SoundStudio 3 for Mac:
Audacity for Mac, f ree:
ClickRepair for Mac and PC:
BIAS Peak LE for Mac:
BIAS Peak for Mac: www.bias-inc.com
Roxio Toast 7 Titanium for Mac:
Roxio Easy Media Creator for PC:
Discwelder Bronze for Mac and PC:
Final Cut Studio for Mac:
E-MU 1820 PCI audio card for PC:
Mark of the Unicorn Traveler:
Tomlinson Holman,5.1 Surround Sound —Up
and Running, Focal Press, 2000.
George Towner/Apple Computer Inc.,Discovering QuickTime —An Introduction for Windows and
FIGURE 8: SoundTrack Pro's FFT (Voiceprint) display.
1 - O tal do Superfreq (BIAS Freq4) não passa de um equalizador paramétrico de 4 canais semelhante ao Waves Q10 que uso no Wavelab... com 10 canais (vide anexo).
Repara que o cara abaixa pontos de "alta frequência mas nem tanto" de modo a fazer parecer que tem mais sinal de médios e graves. (Confesso... já tive de usar esse artifício em algumas digitalizações. Não tem jeito... o mundo digital vive de maquiagem na cara-dura MESMO!)
2 - Ele cita o velho SoundEdit 16 (que usei durante anos e que na época era muito bom, mas que hoje, concordo com ele que está obsoleto), mas ele tinha uma coisa de bom: desencorajava certas "pragas" como compressão dinâmica multibanda que o povo abusa adoidado hoje em dia.
A limitação do SoundEdit é ele suportar só até 16 bits x canal.
3 - Ele também cita o Toast Titanium (software para autorar CDs, equivalente ao Nero no PC, com as mesmas vantagens e desvantagens, diga-se de passagem).
4 - Após ler a matéria, vou continuar digitalizando meus discos com um sinal proveniente de um bom pré de phono analógico a 24bits x 48000 amostragens por segundo (que o povo insiste em chamar de 48kHz, o que é incorreto, já que não ocorrem "ciclos" ou "ondas" e sim "amostras de amplitude" das mesmas), com o máximo de sinal possível sem "clipping" (o que muitas vezes corresponde a refazer o trabalho do zero).
Durante meus testes e experiências, acabei reprovando a de-ênfase RIAA dentro do domínio digital. Adivinha por quê... Excesso de perdas, lógico!
5 - Depois, só depois de digitalizado, editado, etc. aí sim, faço o downsampling para o limite da mídia destino. (Ex.: CD = 44100 amostras por segundo a 16 bits por canal)
6 - A saída as cápsulas podem até não ser lineares, mas pelo menos entregam o sinal inteiro, não um "lego" dele.
Só para completar: Não tenho nada contra o armazenamento digital de áudio não. Aliás, considero até uma solução muito boa para democratizar referências e uma boa alternativa para preservar algumas gravações sem cura. O que eu discordo é a mania de tratarem o áudo digital como "perfeito" (o que nenhum sistema de armazenamento de áudio é), bem como a sua má-utilização, ou mesmo as tentativas desesperadas de tentar faze-lo parecer melhor do que ele é na realidade. O áudio analógico também não é perfeito, mas pelo menos tem se comportado de forma bem mais honesta nesse sentido.
C. H. Picolo.
Concordo Picolo. Já falo isso no meu blog Vinil Na Veia, logo na apresentação, quando uso o termo "mídia honesta". Não se pode, por mais pureza de som que tenha, comparar uma cópia digital de sinal eletrônico com o próprio sinal original produzido a partir do som real de uma banda ou orquestra. E já se sabe porque isso ocorre: A digitalização (Informatização do sinal) de um sinal elétrico para sua posterior reconversão novamente em sinal elétrico fica extremamente prejudicada pela limitação da "copiação" digital que só atende a valores inteiros: 0, 1, 2, 3, 4, 10, 20 etc. e daí por diante; e, sabemos que um sinal elétrico tem níveis "quebrados" como 1,35 milivolts que na conversão digital é "perdido" (Convertido) para o valor "zero", assim como o valor (nível) 1,54 é "arredondado" para o valor 1, já que os valores binários são 0 e 1, apenas. Desta forma, você terá uma onda só com valores inteiros o que não corresponde com a realidade do sinal elétrico da gravação inicial (Analógico) que é especializadíssimo, tendo valores como 0,1; 1,33, 2,45, 2,73 e 4,31 milivolts e assim por diante. Isso traduzindo para um sinal elétrico digital (reconvertido, óbvio, para analógico, pois não escutamos zeros e uns), seriam 0, 0, 2, 2 e 4 milivolts.