Friday, April 30, 2010

408 Production Synopsis 9

This week our group spent most of our lab time setting up the tracks for the mixing process. This was done by creating group sums for each prominent section of the songs (drums, vocals, bass, rhythm and sometimes others.) We spent some time tracking gang vocals for one song in room 100 using a 414 in cardioid. We decided to not use baffling so that the sound would be more spacious sounding and not dead. We had a piano part that we recorded last week and used it as the vocoding instrument for a vocal line. It took us around an hour for us to tweak the vocoder to sound like what we were envisioning, but we are really happy with the sound now. Earlier today we spent most of our time doing drum replacement and vocal comping. We have the kick and snare sounds dialed for about half of our songs now and we are all getting really fast at the replacement process. We also did a few background vocal takes for Neon Cannonball and Chad feels that everything is completely tracked for the song. We are planning on meeting up in the next couple of days outside of class to complete the rest of the drum replacements.

Wednesday, April 28, 2010

EQ for Cyndi HeadLauper

On MTA 980 board

N/A = 12:00, 0 boost/cut

Kick: Lo EQ-10:00, +3; LoMid EQ-11:00, -10; HiMid EQ-N/A; Hi EQ-12:00, +3
Snare: Lo EQ-N/A; LoMid EQ-11:00, -5; HiMid EQ-N/A; Hi EQ-11:00, +3
Drum L: Lo EQ-N/A; LoMid EQ-11:00, -5; HiMid EQ-N/A; Hi EQ-11:00, +3
Drum R: Lo EQ-N/A; LoMid EQ-11:00, -5; HiMid EQ-N/A; Hi EQ-11:00, +3
Bass: Lo EQ- 1:00, +3; LoMid EQ-11:00, -3; HiMid EQ-12:00, +3; Hi EQ-12:00, +1
Guitar: Lo EQ-11:00, -4; LoMid EQ-11:00, -4; HiMid EQ-N/A; Hi EQ-N/A

Tuesday, April 27, 2010

Structural Phenomena As Observed in ‘All Along the Watchtower’

The song ‘All Along the Watchtower’ was written by Bob Dylan and is featured on his album entitled John Wesley Harding which was released in December of 1967. The track only took 5 takes to record and in the end take 3 and take 5 ended up getting spliced together for the master. When listening to the recording, it is obvious that very minimal instrumentation was used. This is due to the fact that Dylan was trying to get back to his folksy roots and move away from the sound of his 3 previous electric albums. The song has an ABABAB structure where the Verse section (A) lasts for 16 bars, or 2 phrases of 8 bars. The Channel section (B) last for 8 bars and features Dylan on harmonica. The actual instrumentation of the song consists of Dylan’s vocals, acoustic guitar and harmonica with bass guitar and drum accompaniment. The feel of the song creates a forward movement with a fairly simple steady folk drum beat (that only changes once throughout the whole song, bass drum pattern changes at 1:30) and the bass playing the root and function notes of the chord. The song starts with a 4 bar intro of guitar, then drums, electric bass and harmonica come in to support the main focus of the song, which happens to be Dylan’s lyrics. The song is unique in that the lyrics never repeat themselves and there is no chorus. Also, the main chord progression, C#m-B- remains the same throughout the entire song, which also reflects how important the lyrics are intended to be understood.
In contrast, Jimi Hendrix’s version of ‘All Along the Watchtower’ was released on the album ‘Electric Ladyland’ in September of 1968. Hendrix actually heard Dylan’s version of the song on January 21, 1968 when he was starting the recording process of the album at Olympic studios in London. Jimi’s engineer for the album, Eddie Kramer, noted that Jimi started working on recording the song soon after he heard it. Session player Dave Mason was in the studio and played the acoustic rhythm parts for the song. During the session, Jimi’s regular bass player at the time, Noel Redding, had some issues with how things were being handled and ended up leaving. Jimi took up the electric bass and played the part for the recording we hear today. Kramer’s final mix of the song happened 5 days later, but when Jimi listened back to it, he felt that it needed something more. Jimi went on to overdub guitar parts during June, July and August, at a studio on New York called the Record Plant. The master tapes of the song moved from the original 4 track to a twelve track, and finally to a sixteen track recorder. This allowed Hendrix the time and opportunity to swap out solo and go back and forth between takes.
Jimi’s version contains an extended solo section, a revision of the guitar rhythm from the one Dylan had created, dense instrumentation and many more differences. The rhythm motif of the piece happens a little differently in Hendrix’s version, with a slower half time feel with the second chord landing on the second beat, while the Dylan rhythm emphasizes the the change on the ‘and’ of 3. This difference creates a much heavier feel. Along with the big drum fills, Jimi practically playing solo bass lines, newly invented guitar tones, auxiliary percussion, and many overdubs, the whole sound is plain huge and heavy sounding.
Many of the sounds Jimi had in his mind when producing and composing songs such as ‘All Along the Watchtower’ can be traced back to the principals of African music. Many of these same principals can be used to explain theoretically what Jimi was hearing when he chose the rhythms and voicing he used in his songs.
Much like what is heard in African music, Jimi uses interlocking pitches and rhythms as individual parts; when these parts are joined together, we get the powerful sound that we hear in songs such as ‘All Along the Watchtower. An example of this can be heard in the into of the song when the vibra-slap is used to fill the quarter note rests. The song keeps the energy moving forward in a much more consistent manner, rather than letting the momentum drop with space in between the rhythmic hits. Joined with
Buddy Miles playing tom fills between the rests, the prominence of the two percussion instruments create a very powerful effect. The giant sound is then continued with tambourin panned to the opposite side of the vibra-slap, consisting of constant eighth notes to make an even denser mix.
The next quality of sound that can be traced to African music is the songs ‘buzzy’ timbre. Hendrix was one of the first to use very high amp levels when recording electric guitar which caused harmonics to be produced which are very pleasing to the human ear. The performance that we are hearing is very clean, though most of the audio is overdriven to the point where it sounds sweet and inviting. I think that the reverb and delay that was used in the song helps to accent the overdriven sound because it feels like the dirtyness continues throughout the whole song as every instrument is super wet as though it is being sustained. Jimi’s solos never seem to end with this type of mixing treatment.
During the extended improvisational period of the song, each phrase of Jimi’s solos seem to be independent of each other. There is a call and response type feel to what the guitar is playing. The guitar is being panned from left to right and then back again to embellish the technique and create an open rhythmic sound similar to that of a hocket, or a back and fourth melody line between instruments. In the case of Jimi and his virtuosic guitar playing, he can do it by himself.
Throughout the entire Hendrix version, the same 4 bar chord progression is heard for the whole song. Though it might seem redundant on paper, the song is kept on its ‘toes’ by including tasteful variations of the ostinato rhythm throughout. The way that the chord progression starts out in the song is very different as the song progresses. Right away at 10 seconds in, the acoustic guitar strumming pattern expands from the rigid hits that we hear in the beginning. Jimi also does strong electric guitar strums in between vocal phrases to add emphasis and continuation to the lyrical line. I believe that the guitar solos that separate the verses could actually be considered choruses when related to pop music. They serve as the hook to the song as the same tone is introduced every time, other than during the extended guitar break (which would be where the conventional guitar solo section would be anyways).
That leads to the discussion of the solo section and how each 8 bars introduces a unique guitar tone and feel. During the first 8 bars, Jimi plays a solo that is in the form of a minor pentatonic and in context, is a fairly straight forward sound for the time. This set up Jimi to go in numerous directions; he decides to bring in a slide (“METal on METAL”) to create an open and wandering feel. This leads to a wah explosion where the back and forth panning occurs. The last phrase is when the instrumentation comes together as Jimi chugs out chords in an acceding manner to reach the climax of delivering the last verse.
The last point that is worth a mention is how the tempo fluctuates and changes throughout. The song has a very ‘alive’ feel in that the song seem to ‘breath’ faster and slower, wavering around a stead beat. The beginning of the song starts out somewhat slow, and when the guitar part comes in, it is sped up slightly until it winds back down during the verse sections. Every section where the guitar is a focus point, the drums and rhythm section speeds up as if to keep up with Jimi and also try and hold him back. I believe that in relating this to the theory of music and that of African Culture this can be tied to a type of community participation. The repetition of the chord progression further exploits the example of community participation because as the song moves along, the more momentum it gains. Every band member is feeding off someone else and you can hear the energy though out the recording.



Works Cited

Bjorner, Olof (May 7, 2000). "Still on the Road: Bob Dylan Recording Sessions". Olof Bjorner.
McDermot. Kramer. “Setting the Record Straight.” 1992. Grand Central Publishing.
McDermot, Kramer & Cox. “Ultimate Hendrix.” 2008. Hal Leonard Corporation

Friday, April 23, 2010

408 Production Synopsis 8

This week all the main lead vocal parts were finished for the album. We used the same set up and settings as we have been using for the previous weeks: CM7, Neve, Distressor. Everything has been going fairly smoothly with the exception of myself getting a little frustrating with my singing takes...I just need to practice and get better. We met twice outside of our scheduled lab time this week in order to rough in mixes so that we will be one step closer once mixing OTB time comes around. The first step that we are trying to accomplish is to use replacement on a lot of the snare hits. We also have been messing and playing with guitar tones as we tracked almost all the guitar parts dry and have been figuring out what tones we want coming out of the sansamp plugin. There are so many choices! On top of that, now that we know how to use elastic audio, it seems like we will never be able to work on the mixes enough to how we could ideally make them sound. Other than the snare replacement, we are working on cleaning up the drum sections, making the bass fit in the middle with the kick and snare, as well as getting the vocals to sit appropriately. We plan on finishing up all recording with a few auxiliary sounds such as wood block, tambourine, piano, vocoder, backing vocals and gang vocals.

Thursday, April 22, 2010

techniques of 408 6

4 Independent Headphone Mixes

  • Create 4 Stereo Aux tracks.
  • Create independent bus mixes from each instrument track and send to any of the stereo aux outputs.
  • Send the 4 HP aux tracks to B1, B2, B3, B4. These are now mono summed HP outputs.
  • Go to the I/O menu to name each buss HP mix is going to be for each player (drum hp, bass hp, vox hp, guitar hp).
  • Send TT out of B1, into HP 1 amp, out into A of room 100 HP patchbay.
  • For multiple outputs of the same mix, create a send under the send section from an already outputted HP mix.
  • Stereo In, Aux mono out; otherwise only 1 side of HP will work.
Memory Locations
  • Apple, 5 on numeric keypad. Memory location menu comes up of all memory locations.
  • Press Enter to pull up memory location dialog box. Select 'no time properties' (none). Under general properties, track show/hide, zoom settings, track heights, group enables.
  • Erase everything you don't want to see (all except drums).
  • Name 101 and select what you want (drums).
  • Vocals 102...ect.
  • To recall memory location, on keypad press . 101 . or 'period 101 period'.
OTB Compression
  • Line 1 inputs
  • Unity gain all faders
  • Pan positions set
  • Activate line 1 buttons
  • Line 1 pot fully counter clockwise
  • Engage mix button for each track
  • Take off 2 track and mix button on master
  • engage group 3-4 and take out mix button (after initial settings, sums to stereo)
  • Put up group 3-4 monitor level almost full and pan hard left and right.
Parallel
  • One dry, one compressed...mix to taste.
  • Engage group 5-6 for compressed sound.
  • Group insert send, to compressor.
  • Group insert return, from compressor.
  • Bring up dry drums, then mix up compressed drums underneath to taste.
2 Stage Compression
  • Take group 3-4 and make insert send to Millennia.
  • Instead of going back to insert return on group, send to 2 new channels on board.
  • Use the 2 new channels on the board and group to 5-6.
  • Now Millennia compression is going into Distressor and then out. Adjust to taste.
Drum Replacement
  • Doing by hand is the most efficient approach.
  • 1st create new audio track.
  • Select drum section that you would like to use and copy.
  • Make sure the tab to transient button is engaged.
  • Press tab to go to transient.
  • Press semi colon to go to blank audio track below.
  • Press V to paste audio.
  • Press P to go back up to original track.
  • You should you the version that is the latest copied version so that it is the closest to the unadjustable threshold of the tab to transient.
  • Apple + or Apple - is right hand side of region adjustment (on keypad).
  • Option + or option - is left hand side of region adjustment (on keypad).
  • Adjust the grid resolution to fine tune region selection.
  • + or - to nudge region back and forth.
Elastic Audio
  • Used to tweak performances.
  • 2 modes of analysis.
  • 5 different plugins.
  • Polyphonic - for guitar, voice, orchestras.
  • Rhythmic - drums and percussion.
  • Monophonic - for bass, violin.
  • Varispeed - affects pitch and acts like a tape deck.
  • X - form - renders audio before playback so that CPU isn't utilized.
  • To affect Vocals: Choose Polyphonic, go to analysis, protools selects markers for regions (event markers).
  • Assign markers in analysis view.
  • Option click to subtract markers.
  • Double click to add markers where needed.
  • Or remove by select selection, delete.
  • You can also right click audio for elastic audio menu (when is analysis mode).
  • Adjust sensitivity of event markers.
  • For long sustained sound, don't use a lot of markers.
  • Usually at start of transient.
  • Add a bunch for glitchiness sound.
  • After analysis, create warp markers .
  • In order to change things, use 3 types of warp.
  • Telescope - default setting - good for long phrases.
  • Accordion - Shift click for 3 warp markers.
  • Range
  • Use the trimmer tool (time compression expansion tool or TCE) to adjust and warp region.
  • Monophonic is just used for a different sound.
  • Varispeed changes pitch and time.
  • Most elastic audio plugs have window selection - window acts as a gate, while 'follow' is how the plug handles the regions dynamics.
  • In rhythmic, 'delay rate' in window adjusts the gate time reaction.
  • To fit bass and kick together, use monophonic. Assign analysis points. Put the bass transient slightly behind the kick (up to 15 milliseconds) so that tone sounds like it is coming from kick and EQ/Compression of the both instruments don't conflict.

Friday, April 16, 2010

408 Production Synopsis 7

During the last few weeks of tracking, finishing vocals has been the main objective. We have been using the Wunder CM7 in the midilab with the vocal booth walls as baffling. The main signal path has been CM7-Neve Pre-Distressor-PTs. The purpose of the Distressor has been to slightly even out vocals so that they are a little closer to being ready for final mixing down. Depending on the material, the parameters for the Distressor have been as follows: ratio either 3:1 or 6:1, input 5, attack 5, release 4, output 4, high pass engaged. We have finished vocals for 4 songs and are well on our way to being done with tracking. Other than vocals, we have been utilizing our time to complete a ton of auxiliary sounds. For the first song on the album, Caught Up, we have a military march sound happening. A marching snare was double tracked with a 57 in room 100 with a small amount of baffling. Marching bass was also recorded, though we have already talked about it not being necessary. Many tracks of stomping on the wood floor has been recorded, as well as chanting. Toms were also recorded with a single 414 in omni, they sound super open and huge. Toms and claps were also recorded for Neon Cannonball. A kaos pad was used on Neon Cannonball as well.
One of the coolest effects that we have recorded thus far has been achieved by using the roland vocoder. It took a lot of getting used to, as the signal path was quite confusing, but we were able to get the hang of it. We created an auxiliary track in PT for the guitar track that we wanted to use as the vocoder music input. Sends were created from the guitar tracks to the new aux and sent out to the patch bay. From here, a TT to TS was used to send the signal into the vocoder's line level at 0dB. We used a 57 and plugged it into the microphone input on the vocoder to act as the vocoders 'voice trigger.' The microphone level was set to approximately 10 o'clock. The wet/dry mix was set to fully wet to ensure only the vocoder's sound was being heard and not what I was speaking. The volume was set to approximately 3 o'clock. The frequency adjustment had the biggest boost in the mid range, or between the 6 and 7 knobs. The lows were almost nonexistent and tapered off below the 6 knob. Above 7, 8-9-10 were around 0dB, while the knob 11 was fully 'off.' We used the 'Vocal Amp' output with the level selector at high. A quarter inch was taken from the vocal amp and into the millennia; from here the signal was routed through the patch bay and back into PT. A new 'voco' audio track was then made in PT to record what we were hearing from the vocoder.
It took quite a while to get used to tracking with the vocoder, as the guitar part that we were recording with was very syncopated, which isn't an ideal sound. In the end we used a couple of short phrases that went along with the lyrics of the song for a powerful birdge section.

Techniques of 408 5

This week we learned about detailed automation approaches. There are two ways to understand automation; through real time recording, or through graphic editing.

Real Time:
  • Bring up automation window by apple, 4 (on keypad) or under automation, in the window tab.
  • You can 'suspend' all automation if you want for all tracks.
  • Click plug-in to automate plug in.
  • When automation tab is red, it is enabled.
When looking at a track
  • Go to write mode, put up volume level so you can hear what you are doing.
  • Record and move fader to apply automation.
  • Write mode overrides any previous automation points.
  • Make sure selection is enabled in automation window.
There are 7 modes for automation
  • 'Off' can be enabled to turn off any automation.
  • 'Touch' mode only adds automation when you touch fader and then returns to what is already has been automated.
  • Can be used to combine old automation with new adjustments.
  • Under preferences, mixing, automated time (for setting up how slow/fast you want the touch mode to return to previous automation.)
  • 'Latch' mode plays back automation that has been made, and once you move the fader, it stays in place and moves only when you adjust.
  • 'Trim' function tweaks automation only slightly, creating a composite of both old and new automation.
  • Trim can be enabled with the other functions as well.
Viewing and Editing Automation
  • Use the grabber tool to create break points.
  • Option, Click to erase break points.
  • Apple, Click to add break points.
  • The little arrow at the bottom left of each track can be used to show automation of specific automation. Click the '+' for other independent automation views to be opened.
  • Double click to select entire track.
  • Highlight section and Press Delete to get rid of all viewable automation.
  • Use pencil tool to draw in automation.
  • Select Wave type under pencil tool and select the resolution (bars and beats, and 1/8 or other appropriate beat type).
  • Edit, Copy Special to send automation of volume, to pan as well, or whatever other automation you choose.
  • Make sure to un-group to do automation for 1 track of group.
  • Use selection tool to highlight and move automation.
  • Hold Command key to fine tune automation.
Plug In automation
  • Control, Option, Apple, Click pot button and select automation option.
  • Go to latch mode with the plug in automation selected and edit in real time with the plug in.
Automation, things to keep in mind
  • Write mode is destructive.
  • Latch mode only applies to one automation.
  • Use Escape key to scroll through edit menu tools.

Friday, April 9, 2010

Digital Audio

by James Meder


History - Audio’s Transformation from Analog to Digital


1976 - “The first 16-bit digital recording in the US was made at the Santa Fe Opera on a handmade Soundstream digital tape recorder developed by Dr. Thomas G. Stockham.” (Pohlmann)

1982 - “The first digital audio 5-inch CD discs marketed, merging the consumer music industry with the computer revolution.” (Pohlmann)


1988 - “For the first time, CD sales surpassed LP sales, leaving CD and cassettes as the two dominant consumer formats...” (Pohlmann)


1998 - “Jonell Polansky produced the first 24-bit 48-track digital recording session at Ocean Way on Nashville's Music Row.” (Pohlmann)


2001 - “Apple Computer introduced on Oct. 23 the iPod portable music player. (solid-state iPod released Jan. 11 2005).” (Pohlmann)


Digital Audio Basics


“At its most elementary level, it is simply a process by which numeric representations or analog signals(in the form of voltage levels) are encoded, processed, stored, and reproduced over time through the use of binary number system.” (Huber)


Digital Music Systems use a Binary (2 base) System which is encoded in media as: 1 or 0, On or Off, Voltage or No Voltage, Magnetic Flux or No Flux, and Optical Reflection Off of a Surface or No Reflection.

Sample Rates, Bit Depth and Resolution


In Analog, continuous signals are passed, recorded, stored, and reproduced as changes in voltage levels (change over time).


Depending on the sample rate, periodic periods of time are processed by creating a binary word that represents the signals level and waveform. These binary words are stored and can later be recreated during the D/A process.


A sample rate of 48 kHz represents a sample every 1/48,000th of a second.


The higher the sample rate, the higher bandwidth of signal is available. This results in the ability to clearly represent higher frequencies of a digitally recorded sound (higher resolution).


“During the sampling process, an incoming analog signal is sampled at discrete and precisely timed intervals (as determined by the sample rate). At each interval, this analog signal is momentarily ‘held,while the converter goes about the process of determining what the voltage level actually is, with a degree of accuracy that’s defined by the converter’s circuitry.” (Huber)


A binary encoded number is then given to the computer (hard drive or storage device) that represents the analog level.


From here, the audio can be stored and referred back to in the future when the timed interval is reassembled with the binary word during the D/A process.


The converter then continues the process by quickly moving on the the next sampling period.


“The Nyquist Theorem states that in order for the desired frequency bandwidth to be faithfully encoded in the digital domain, the selected sample rate must be at least twice as high as the highest frequency to be recorded. If you wish to record and capture a frequency of 20 kHz (upper level of human hearing), the sample rate must be at least 40 kHz.” (Huber)


‘Quantization’ represents the amplitude level in relation to the sampling process. Voltage levels of the signal are processed and stored as binary digits so that they can be stored and later recreated.


Currently, the most common binary word length for consumer audio is 16-bit (cd quality).

Added internal headroom at the bit level, helps reduce errors in level and performance at low-level resolutions.

Also, the higher the bit level, the more headroom is allowed, creating less of a chance for clipping and digital distortion to occur. In the near future, system of 32- and 64-bit resolution will become the norm.

Analog-to-Digital and Digital-to-Analog Conversion

“In its most basic form, the digital recording chain includes a low-pass filter (or anti-alias filter), a sample-and-hold circuit, an analog-to-digital converter, the circuitry for signal coding (or multiplexor), and error correction.” (Huber)

Low pass occurs in order to block frequencies that are greater than half the sample rate frequency from having to be converted.

A Sample-and-Hold (S/H) circuit holds and measures the analog voltage level for the duration of a single sample period, its length is dependent on the sample rate.

For the next step, A/D conversion happens by encoding the signal into a binary a word. This is the most important step because the converter has to efficiently create the binary word from a DC voltage ? level that is correctly quantized to the nearest step level, very quickly in order to move on to the next sample.

The digital data then needs to be sent to storage, but before that happens, more processing and conditioning takes place, which includes: data coding, data modulation and error correction “(synchronization and address information)”. Rather than just keeping the data raw, it is coded into a form that can be easily and accurately stored and found.


An important process of digital audio data coding is pulse-code modulation (PCM).


“The density of stored information within a PCM recording and playback system is extremely high.” (Huber) In order to compensate for any problems in the audio due to the large amounts of audio data, many forms of error correction is used.


A mathematical pattern is used with PCM and error correction, where the binary word is sent in random order to be stored in a binary bitstream. This process also allows for the corrupted audio to become available later when a ‘puzzle piece’ of the bitstream is regenerated during the D/A conversion process.


Without this part of the coding process, digital audio would be close to useless because it ultimately saves the quality of the audio.


The digital reproduction chain (D/A) for recreating the binary word in order to be heard, is much like the A/D conversion happening in reverse.


The recorded data is restored to its modulated binary state and into pulse code form.


Next up is the digital-to-audio conversion where the analog voltage levels are reinstated from the binary word.


A sample-and-hold happens to distinguish the most-significant to least-significant bit.


The final step is a low pass filter so that the signal doesn’t distort due to high frequency harmonics.


Within every step of the digital ‘reproduction chain,’ summing each 1 or 0 together determines the voltage output.



Digital Audio Transmission


“When looking at the differences between the distribution of digital and analog audio, it should be kept in mid that, unlike its counterpart, the transmitted band with of digital audio data occurs in the megahertz range...” (Huber)


Digital audio is very susceptible to errors and signal irregularities due to the large bandwidth that is required.


Useable transmission of digital audio signals include: AES/EBU, S/PDIF, MADI, ADAT Lightpipe, TDIF, and mLAN.


AES/EBU (Audio Engineering Society and the European Broadcast Union) audio transmission is used between professional audio devices and is capable transferring two channels of interleaved audio through a single XLR cable. This is possible by having pin 1 of the XLR acting as the ground and having pin 2 and 3 carry the two signals.


S/PDIF (Sony/Phillips Digital Interface) is used to connect consumer grade 2 channel audio devices to professional interfaces and the like. Can be used with a single conductor unbalanced phono (RCA) cable, as well as an optical ‘Lightpipe’ connection. Can work as a link between multichannel data devices like that of a surround sound system.


ADAT Lightpipe uses the same optical Lightpipe cable as S/PDIF, but is capable of handing up to 8 channels in one direction. The 8 channels can link multiple audio devices and with two cables, is also able to handle 8 In/Outs simultaneously.


TDIF (Tascam Digital Interface) uses a 25 pin D-Sub cable that is able to send and receive 8 digital audio signals bidirectionally. This is the Cable system that is used to run audio from the 192’s to the HD PCIe audio cards in the Mac.


A digital distribution device can be used to route audio devices together to prevent jitter and wordclock errors.


Word clock and Jitter


“Jitter is a time base error...It is caused by varying time delays in a circuit paths from component to component in the signal path. The two most common causes of jitter are poorly designed Phase Locked Loops (PPLs) and waveform distortion due to mismatched impedances and/or reflections in the signal path.” (Katz)


Jitter occurs when long cables are used with incorrect impedances or the source impedance is not correctly matched at the load. It can lead to sound waves that were initially square to become round, fast amplitude times can become slow, and the zero crossing point of the waveform can be less accurate.


However, when looking at the binary word of a square wave that is encountering jitter, it would be the same as the original ‘unjittered’ binary number. The only way you would be able to hear the difference is through obvious distortion; which usually is clicks or tics in the audio.


During D/A conversion, the process where jitter occurs is during the sample and hold period. If this process isn’t stable, then the digital audio won’t be able to return to an analog signal quickly enough and result in “loss of low-level resolution caused by added noise, spurious (phantom) tones, or distortion added to the signal.” (Huber) With a jitter problem, a digital converter can shrink the dynamic range of a recording by a lot. When listening back to such a recording, it can sound grainy, have loss of definition, have loss of stereo width, and obvious signal loss.


The purpose of Wordclock or a Master Clock is to reduce jitter and to link multiple converter devices to the same sample rate times, as well as the same sample-and-hold periods.


Only one Master Clock can be used at once so that each devices’ internal clock can run “within a connected digital distribution network.” (Huber)


A wordclock is only necessary when using systems with various conversion devices.


Sound Quality


Tech Side...

There are ups and downs to both analog and digital audio. In analog recording, the tape is able to capture a continuous signal. If this same signal were to be captured in digitally, a bit depth would have to be chosen and the signal would need to be quantized.


The introduction of bit depth and quantization brings about the signal-to-noise issue and how accurately a signal can be reproduced. In a similar manner, when recording in analog, a signal-to-noise (S/N) ratio is introduced and can cause the dynamic range of a recording to suffer.


Dither is another component that separates analog from digital. The digital process of sampling and quantizing can create a ‘squared off’ understanding of a waveform and when recreated, low level harmonic distortion can be heard due to the ‘square wave’ sound of a sampled and quantized piece of digital audio. This happens during the A/D process when the Least Significant Bit (LSB) is encoded into the binary word. It can be avoided by adding dither, which is a small amount of noise. When noise is added, a converter has an easier time encoding, or deciding whether to use a 1 or 0 as the LSB.

Ultimately, the low level harmonic distortion is a lot more obvious when recording at a lower bit depth.


When converting from a higher bit depth (24) to a lower bit depth (16), it is a good idea to use dither. The converter will have an easier time deciding the LSB for the 16 bit signal, thanks to the dither.


If you are transferring an analog recording to digital, you don’t need to worry about dither because the tape noise will naturally decide the LSB.


Opinion Side...

Some engineers like recording to tape because they believe that it will yield a warmer, more natural and vintage sound compared to the sterile sound of digital. Other engineers like recording digitally because the S/N ratio is important to them and they feel that it will give a more exact rendition of the performance. Digital can be a lot more dependable and can be a lot more portable. If you like the sound of analog, there are many tape emulators on the market; hardware and plugin.



Works Cited



Huber, David Miles. 2005. Modern Recording Techniques. Massachusetts: Focal Press.


Katz, Bob. 2002. Everything You Always Wanted To Know About Jitter But Were Afraid To Ask. Mastering Audio, The Art and The Science. Massachusetts: Focal Press.


Pohlmann, Ken C. 1995. The Digital Revolution. New York: McGraw-Hill. Retrieved from http://history.sandiego.edu/gen/recording/digital.html

Recording Presentation Week 2 Notes

Sound Reinforcement (Live)

Electricity and sound physics: volts, electromotive force; Ohms, resistance in DC; current flow, AC/DC ground; direct current, electrons go one way (sound cables); alternating current, electrons (both ways). Articulation loss happens when 15% of consonants are lost, poor speech is heard. Make sure proper gain structure is kept. Different types of mics used: Piezo mics, wireless systems, lapels (lavalieres), boundary mics (PZM's), Shotgun mics. When mixing for live mix, take into consideration of frequency response curve, proximity effect, unbalanced mic cables, distortion and dynamic compression (clipping). You can use limiters on all speaker s to make sure feedback level isn't reached. Noise Gates are useful if mic isn't always being used. Loudspeakers never have flat frequency responses so use an EQ to carve out resonate frequencies. Crossovers are used to send certain frequencies to certain speakers. Horn speakers are used for high frequencies (tweeters). Passive Crossovers send signal to all speakers while active crossovers choose what frequencies are sent where. Large speakers sometimes use tweeters in the back to compensate for high frequency loss. It is important to have mixing board off-center in venue so that every position can be taken into account when mixing.

California Studios

Gadgetbox Studio - Andy Zenczak - Started out with 4 track, plays drums and piano, inspired by John Mcentire from Tortoise. His studio has 5 inches of space between walls and floors. Also used bamboo for some baffling.
M.A.R.S. Studio - Ken Capitanich - One room for live tracking and mixing. Started out recording live shows. Likes Digital Performer and loves using tube equipment.
Indigital Studio - Brody Bergholz - started out in a band and has learned through school and master classes.
Suspect Studios - David Gakle - Large live room in studio. Also a drummer.
7 South - Steve Powell - Invested in studio with some friends. Established in the 80's in Santa Barbara.
Conway Studios - Buddy Brundo - Uses an SSL XL console.
Common Factors of Studios: tube mics and analog gear, comfort in appreciated, most owners teach, freelancing is important, started by buying a building and starting to record, know a lot about the technical side of things.

Microphones

Basically a transducer that turns air pressure to an electrical signal. Alex Bell widespread the use through the invention of the telephone. Though the telephone mics used used carbon diaphragms which have a narrow frequency range. Dynamic mics use a voice coil to achieve electromagnetic induction. Requires a large physical movement, which is why it is best for drums, transients become softer. Ribbon mics use an aluminum 2-3 micron thick ribbon. Condenser mics are based on the electrostatic principal. Created by a circuit between 2 plates (1 which is moveable). Speakers can be used as microphones, though a limited frequency response is represented. XLR cable sends signal via Pin 2 (positive) and pin 3 (negative) and pin 1 is ground.

Phil Spector

Phil was born a Russian Jew and possibly inbred by cousin as parents. His mom was very overprotective and demanding. He became a natural at the guitar and started taking lessons with Barny Kessel. After high school he worked as a court room scribe. Began writing songs and went to Fold Star Studios to record the song, 'To Know Him was To Love HIm,' which reached 88 on the billboard charts. Phil is introduced to Brill Building and Phil's first production 'Corrian for Hill and Range' went to #9 on the billboard charts. Started using Gold Start as main studio and produced 'I Love How You Love Me.' Ronnettes 'Be My Baby' charted at #1 and is claimed to be Phil's best interpretation of the wall of sound. Often times he started the recording process by using a guitar track. He was know to mess with drums a lot and was very particular in how they sounded. All of his sessions costed tons of money because of how long it would take to record and get everything right. His dad committed suicide when he was young and it affected him greatly though out his career. Hired karate instructors to become his bodyguards. The song 'Mountain High, River Deep,' by Tina Turner was the beginning of the end for his wall of sound sound. The general public started to follow artist who they could follow as they developed there sound such as Dylan and The Beatles. When working with the Ramones, Phil forced them to record with strings and session musicians instead of the actual band members.

Chess Records

Chess was a record company founded by Leonard and Phil Chess which primarily focused on monopolizing and popularizing blues music. Notable artists included: Muddy Waters, Bo Diddley, John Lee Hooker, Eddie Boyd. A lot of songs that were written by Chess artists were taken by popular white artist of the time and turned into big hits (Bob Dylan, Elvis, The Doors, Beach Boys, Led Zeppelin). Many female artists were made popular by the label: Jackie Ross, Koko Taylor and many others. In the late 50's, Chuck Berry joined the label and was a big part of getting the word out about Chess.

The Beatles

The Beatles formed in 1960 and had their first EMI session on June 6th, 1962. Their first proper session happened on September 4th, 1962 when Ringo was part of the session. For the song 'Love Me Do,' a session player was brought in to play drums. Please Please Me was released in 1963 and was recorded in a single day. It was engineered by Norman Smith, who encouraged instrument leakage for a live feel. It was recorded with a BTR-3 twin track machine. The record went to #1 of UK charts for 30 weeks. Mics for the record included: drums (2 mics) STC 4038 ribbon mic for OH 4033 - A dynamic and ribbon for kick. Vox AC 30 amps for guitar, miced with U47 or U48 set to cardioid. The U48 set to figure 8 was used for vocals. By January 1964, The Beatles used a 4 track, overdubs were done without headphones. A standard mix consisted of track 1, panned hard left, track 2 and 3 in the middle, and track 4, panned hard right. Half speed overdubbing was done on 'In My Life' with the piano solo. Ken Townsend developed Automatic Double Tracking, which was used quite often.

San Francisco Recording Studio's In the 1960's

Original Coast Reocrders was purchased by Bill Putnam, who was the first to use artificial verb, multiband EQ and stereo recordings. Commercial Recorders was a studio that did mainly voice over and worked a lot with SF Giants commercials. Columbus recorders was part of the sentinel building and worked with artist such as The Grateful Dead and Credence Clearwater Revival. The dead session were very disorganized and one engineer mentioned that it was like 'trying to organize a school of fish.' Golden Gate Records did a wide range of projects, from big bands to orchestras. The Great Society recorded there and 'Somebody to love' was done there. Roy Chen Recording featured recording on a budget and was located in China Town. This recording studio used a bunch of high end gear and eventually went out of business due to the low amount of income they were making. Pacific High Recording featured an indie, experimental, and a laid back atmosphere.

Gates, Compression, Expanders, Limiters

Gates were originally used as noise gates for analog recordings. Gated Verb was discoverd during a Peter Gabrial session using a SSL 4000 board while Phil Collins was playing drums and heard the sound of the drums through the talk back. The source snare was sent into a reverb unit and then to a gate. Limiters are used to prevent over modulation. Analogy for compression: ratio=gravity. The greater the radio, the greater the amount of gravity, where the signal can jump up as high. A limiter is also used as a maximizer. The Fairchild is considered the holy grail of limiters and compressors. Famous compressors include, Urei 1176, Teletronix LA2A, Anamod 670 and ADL 670 (fairchild clones), and a Dramwer DSS201. An expander is used to make loud parts louder and quieter parts softer.

Beginning of Trident Studios

Trident studios opened in 1967. Hey Jude was recorded there with an 8 track recorder. The studio was once home to a very famous Bechstein Grand Piano which was lost sometime later. Malcom Toft started making consoles because he couldn't find a console which he thought had the right requirements for what he needed. When making the first board, he took into account the S/N ratio and Equivalent Input Noise (signal level gain). Started his own console company in 1971 where business was made by word of mouth.

Abby Road Studios

Abby Road Studios is located in London at what used to be a 9 bedroom town home. Now it is broken into 3 different studios. Studio 1 is used for orchestra recordings. Land of Hope and Glory was its first recording in 1931. During the 1940's it was used to create propaganda for the BBC and the war. 'Oh Mein Papa' was the first song recorded at Abby Road to reach #1. The Beatles used it as main studio and perfected controlled feedback to use for recordings. Flanging was also a new technique to be used at Abby Road. Many films and famous albums have been recorded there including: Return of the Jedi being mixed at Abby Road and Radiohead recording The Bends and OK Computer there.





Friday, April 2, 2010

Recording Presentation Week 1

The two presentations that were given this week featured two widely know producers: Butch Vig and George Martin. Early in his career, Butch is know for his work with bands such as Nirvana and the Smashing Pumpkins. He was able to create the heavily grunge rock sound that created a new direction in popular music in the early 90's. He was able to trick Kurt Cobain into double tracking all the guitar parts twice by telling him, "John Lennon double tracks." This lead Butch to be able to sculpt the heavy and raw sound that was heard on the early grunge records. Another interesting fact is that Butch made Billy Corgan play almost all the instruments on the Smashing Pumpkin debut, Gish. On that record, the drum mic set up is identical to the go to set up that we have at the school studio. A d112 and RE20 on the kick, a 57 on the top side snare, 414's as OH's and 421's on the toms.
George Martin is sometimes referred to as the fifth Beatle. He was born on January 3rd, 1927 and began playing piano and eventually realized that we had perfect pitch. He found his way into working at Parlaphone (a division of EMI) records as a lead engineer. It was the littlest branch of EMI and he didn't always get to work with the biggest acts. He was always looking for band that had a unique sound that he could put his 2 cents on. At the age of 29, George took over Parlaphone and was in search of an artist that could be featured to create hit songs. Brian Epstien, the manager of the Beatles, met with George and agreed to listen in on a practice session. George was really excited with what he heard, other than the fact that drummer Pete Best, wasn't really the best... At the consent of George, Pete was replaced by a guy named Ringo Star and the rest is history. The first Beatles album was made in 12 hours at Abby Road Studio 2. The Beatles and George always were looking for ways to push the musical evolutionary envelope, which is heard in all of the Beatles material, especially the during the latter years. Automatic Double Tracking was created with the help of Ken Townsend during an experimenting session where the idea came up to barry the top of the playback head speed on the tape machine. In songs such as 'All You Need Is Love,' a mixture of Bach's Greensleeves and 'In the Mood' can be heard among other Beatles tunes. George went on to help the Beatles reach the top and keep them there by continuing to pursue the greatest sounds and performances that were possible, and of course composing all the background orchestrations and ideas.

408 Production Synopsis 6

This week group C was able to finish up electric guitar parts with our usual set up and continue on to vocals and a few auxiliary sounds. We tracked stand up bass sections for 2 songs in room 100 using a 414 a few inches away from the f hole, as well as 122 about 3 feet back for some added depth. Additional lead lines were done in one of Chad's song with a whammy pedal to give a unique feel. We did some textural experimentation with 3 delay pedals to give some background excitement and drive. The delays were all on different setting and once we had a good sample we just started turning knobs to the rhythm of the songs and it turned out super cool and spacey. Acoustic guitar was tracked for 2 songs in the midilab with a bunch of baffling set up. A 414 was used about a foot away from the neck joint. A shaker and clave part was recorded for a latin section that we have in one song. We used a 57 in the center of room 100 to give a bigger sound, considering the depth that we were able to capture in the big, open room. Vocals were tracked for one song so far using a a 421 and the CM7 in the midilab with heavy baffling. We ran the two mics through the neve pres and into the distressors in opto mode before protools. When listening back to the vocals, its obvious that we need to pay more attention to the compressor settings. All the vocals are definitely useable, but some of the phrases sounded a little lopsided because of the effect that the compressor had on them. Luckily, I was happy with the performance I gave, which rarely happens, and I think it will be easy to salvage the takes. One thing that we need to remember is to engage the high pass filter on the distressors because I think it pulled down the level awkwardly at some points.