Replay is a collaboration track and part of an evolving experiment with multi-tracked guitars revolving around cyclic patterns. More collaborations and sounds to follow.

Arjun on Bass

Sunder – Drums (Instagram and Facebook – @onlysunder)

Mini-glossary of terms in audio production

I’ve used a lot of audio engineering terms over the years and realized that a lot of them were not exactly what I was referring to/meant. While talking to a lot of experienced audio engineers, I’ve always found the below glossary useful to convey my objectives effectively. Hopefully this serves as starter boilerplate for more research with more terms to be added on.  A lot of these and more are covered in Coursera’s excellent course on the Technology of Music Production.

Nature of sound


Tracks, Files and Editing



Dynamic Effects

Filter and Delay Effects

Nature of sound

Amplitude: Size of the vibration of sound. Larger sizes (louder sound) indicate louder amplitude. Measured in decibels. Multiple places in the signal flow where we measure amplitude.

  • In the air: dBSPL or decibels of sound pressure level
  • In the digital domain: dBFS or decibels full scale

Compression: Compression is one of the most commonly used type of dynamic processing. It is used to control uneven dynamics in individual tracks in a multi track mix and also to be used in creative ways like decays of notes and for fatter sounds. Compressors provide gain reduction which is measured by metrics like Ratio control.

  • For example a ratio like 4:1 , means audio that goes above 4 dB above Threshold will be reduced to it only goes 1 dB above only.

Decibel: The words bel and decibel are units of measurement of sound intensity. Bel” is a shortening of the name of inventor Alexander Graham Bell (1847-1922).

  • A bel is equivalent to ten decibels and used to compare two levels of power in an electrical circuit.
  • The normal speaking range of the human voice is about 20-50 decibels.
  •  Noise becomes painful at 120 db. Sounds above 132 db lead to permanent hearing damage and eardrum rupture.

Frequency: Speed of the vibration which determines the pitch of the sound. Measured as the number of wave cycles that occur in one second.

Propagation: Sequence of waves of pressure (sound) moving through a medium such as water, solids or air.

Timbre: Term used to indicate distinguished characteristics of a sound. For example a falsetto versus a vibrato.

Transducer: Another term for a microphone. Converts one energy type to another. A microphone converts sound pressure variations in the air into voltage variations in a wire.

Digital Audio Workstation (DAW)

Bit Rate: Product of sampling rate and sampling depth and measured as bits per second. Higher bit rates indicates more quality. Compressed audio formats (mp3) have lower bit rates than uncompressed (wave).

Buffer Size: Amount of time allocated to the DAW for processing audio.Used to balance the delay between the audio input ( say a guitar plugged in ) to the sound playback and to minimize any delay. It usually works best to set the buffer size to a lower amount to reduce the amount of latency for more accurate monitoring. However, this puts more load on the computer’s processing power and could cause crashes or interruptions.

Sampling Rate: Rate at which samples of an analog signal are taken to be converted to a digital form Expressed in samples per second (hertz). Higher sampling rates indicate better sound as they indicate higher samples per second. An analogy could be FPS i.e Frames per second in video. Some of the values we comes across are 8kHz, 44.1kHz, and 48kHz. 44.1 kHz are most common sampling rates for audio CDs.

Sampling Depth: Measured in bits per sample indicates the number of data points of audio. An 8-bit sample depth indicates a 2^8 = 256 distinct amplitudes for each audio sample. Higher the sample depth, better the quality. This is analogous to image processing where higher number of bits indicate higher quality.

Sine waveCurve representing periodic oscillations of constant amplitude. Considered the most fundamental of sound. A sine wave can be easily recognized by the ear. Since sine waves consist of a single frequency, it’s used to depict/test audio.

In 1822, French mathematician Joseph Fourier discovered that sinusoidal waves can be used as simple building blocks to describe and approximate any periodic waveform, including square waves. Fourier used it as an analytical tool in the study of waves and heat flow. It is frequently used in signal processing and the statistical analysis of time series.


  • Wave: Uncompressed at chosen bit rate and sampling speed. Takes up memory and space.
  • AIFF: Audio Interchange File Format (AIFF): Uncompressed file format (originally from Apple). High level of device compatibility and used in situations for mastering files for audio captured live digitally.
  • MP3: Compressed Audio layer of the larger MPEG video file format.Smaller sizes and poorer quality that the formats above. Compresses data using a 128 kbit/s setting that results in a file about 1/11th of the size of the data.
  • MIDI: Musical Instrument Digital Interface – commonly defined as a set of instructions instructing the computers sound card on creating music.Small in size and control notes of each instrument, loudness, scale, pitch etc.

Tracks, Files and Editing

  • Cycling: Usually refers to musical cycles formed by a group of cycles.Useful for arrangements and re-arrangements
  • Comping: Process where you use the best parts of multiple takes and piece them together for one take.DAWS such as ProTools allow multiple takes that are stocked in a folder in a single track.
  • Destructive editing: Editing in which changes are permanently written to the audio file. Though these can usually be undone based on the DAW undo history in reverse order. Helps when you have less processing power and need to see changes applied immediately and in case where you know you don’t want to repeat that change again. Non-destructive editing uses computer processing power to make changes on the fly.
  • Fades: Fades are progressive increases (fade-in) or decreases (fade-out) of audio signals. Most commonly used when no obvious ending of a song. Crossfades are transitional regions that can bridge regions so the ending of one fades into another.


  • Controllers: Hardware or software that generates and transmits MIDI data to MIDI-enabled devices, typically to trigger sounds and control parameters of an electronic music performance.
  • Quantization: One of the more important concepts. Quantization has many meanings based on the task to be performed but in this context, it’s for making music with precision with respect to timing of notes. To compensate for human error on precision, quantization can help nail the right note at the mathematically perfect time. While great for MIDI note data, it does become challenging but a worthwhile effort to quantize MIDI tracks. Most DAWS have this built-in but this is not a magic wand to blow away all your problems. Quantization in my experience works best when Ive performed a track with acceptable level of timing.
  • Velocity: Force with which a note is played and used to making MIDI sounds more human ( or more mechanical if thats the intent). This typically controls the volume of the note and can be used to control dynamics, filters, multiple samples and other functions.


  • Automation: Process where we can program the arrangements, level, EQ to change based on pre-determined pattern. For example automation to increase the reverb just before the chorus or add delays to a particular part in the mix. 
  • Auxiliary sends: Type of output used in mixers while recording. Allows the producer to create an ‘auxiliary” mix where you can control each input channel on the mixer. This helps route multiple input channels to a single output send. A mixer can choose how much of a signal that needs to be sent to the aux channel. In Ableton, two Aux channels (Titled A and B) are created by default. Aux channels are great for filtering in effects such as reverb and delay. 
  • Channel strip – Type of preamp with additional signal processing units, similar to an entire channel in a mixing console (example).
  • Bus: Related to Aux sends above, a bus is a point in the signal flow where multiple channels are routed into the same output. In Ableton, this is the Master channel – where all the tracks merge together before being exported.
  • Unbalanced cables pick up noise ( from electrical, radio and power interference from nearby cables) and are best used for short distances, for example a short cable to connect different analog pedals with each other. Quarter inch TS (tip, sleeve) cables are used for unbalanced cables. 
  • Balanced cables: Have ground wire and carry two copies of the same signal that are reversed in polarities and they travel down the cable and cancel each other out. Once the two signals get to the other side of the cable, the polarity of the negative signal gets reversed so both signals are in sync. The noise as the signals travelled is picked up by both signals but not reversed in polarity effectively eliminating it.

Dynamic Effects

  • Downward compressor: Same as a compressor which is reducing the level of louder things. When explicitly called out , “upward compressors” bring up the volume of the quiet material. One of the most important effects in audio engineering. Compressors are used for dynamic range and compresses the signal.Expander” Expander expands dynamic range. Louder parts become louder, quieter parts become quieter. Making it louder means amplifying the signal that passes the threshold, it is the opposite of a compressor. 
  • Gate: Provides a floor level for the signal to cross to get through – if the signal is below the gate level if will be treated as silence. Used to cut out the audio when it’s quiet.
  • Limiter: Serves as a ceiling above which the signal cannot pass. It’s essentially a compressor with a very high ratio – as the compression increases, the ratio increases.

Filter and Delay Effects

  • Convolution reverb: Convolution reverbs digitally simulate the reverberation of a physical or virtual space. They are based on mathematical convolution operations and use pre-recorded audio samples of the impulse response of the space being modeled. These use an Impulse Response (IR) to create reverbs. An impulse response is a representation of the signal change as it goes through a system. The advantage of a convolution reverb is its ability to accurately simulate reverb for natural sounding effects. The disadvantage is that it can be computationally expensive. Impulse response is the recording of a real space that we are applying with this mathematical procedure called convolution. In most Convolution plugins, we can find a wide variety of audio files that are representing a large number of real spaces. So, DAWS have large selections where we can simulate different places say a small club versus a stadium.
  • Algorithmic reverb: Algorithmic reverbs are based on the settings we set in our DAW. These simulate the impulse responses. Algorithmic reverbs use delay lines, loops and filters to simulate the general effects of a reverb environment. All non-convolution reverbs can be considered as algorithmic. Algorithm reverbs are kind of like synthesizers  since we are creating the impression of a space with an algorithm of some sort of a mathematical representation. These create echoes using mathematical algorithms to simulate the delays that occur in reverb. Tradeoff is that these may sound less natural than convolution reverbs.
  • Comb filtering: Two audio signals that are playing the same signal arrive at the listeners ears at different times due to a delay. The signals look like a comb when graphed out. 
  • Dry/wet: Dry sounds that has no effects of any kinds of modifications. Raw unprocessed sound. Wet sounds are processed sounds with effects that are added while recording or after mixing.
  • Low Shelf filter: Low shelf filters cut or boost signals of frequencies below a threshold. These usually use “cutoff frequencies” to cut /boost lower frequencies mostly to ensure instruments don’t interfere with each other. Used a lot during guitar EQ mixing and vocals.

ToneWood amp review

I rarely break out my fleet of electric guitars anymore so my usual go-to is my trusty old Cordoba Iberia that’s usually within reach . Having instruments lying around the house is a huge aspect of getting to practice more. The ToneWood amp caught my eye immediately as I’ve been looking for simple amplification while playing outdoors or in places with absolutely poor acoustics where a little echo/reverb or delay can go a long way in justifying the piece I’m trying to play and even serve to feed some creativity.

3 essential knobs

Its essentially a lightweight effects unit that can be mounted on the back of the acoustic guitar to give you amplification and a few effects. There are magnets as part of the install that hook the ToneWood on the back of your guitar and the effects are amplified from the body as the amp picks up sound from the pickup on the acoustic and sends it back via a “vibrating driver” so the sounds becomes augmented with the effects. It essentially blends the natural guitar sound with the effects and comes out the sound hole as a unified sonic experience. The patent explains the concept well and is pretty ingenious.

Magnetic attachment to the back

The natural sound of the unamplified guitar coming from the soundboard seamlessly blends with the effects radiating outward via the sound hole, creating a larger than life soundscape.  All that’s required is some type of pickup installed in the guitar to provide signal to the device. You can connect the ToneWood to an external Amp/PA via the 1/4″ output port and it is iDevice interface that is great if you are on the Mac ecosystem. It also has the 1/4″ standard guitar input and a 1/8″ TRRS I/O for iDevice. The processor takes in 3 AA batteries for an average of 8 hours.

The installation took me about 10 minutes. It required me to slacken the strings, place a X-brace unit inside the guitar pointing the magnets so that the ToneWood amp could attach itself to the outside back of the guitar using the suction provided. This took some adjusting and I’m not sure i’ve dialed in the optimal most optimal position but it’s close enough.Once you stick the batteries in, it’s showtime. The display screen and knobs are intuitive and the barrier to entry here is phenomenally low.

From an effects perspective , it’s really everything you need considering you are playing an acoustic guitar. All the effects come with Gain and Volume settings.

  • Hall Reverb with Decay, Pre-delay and Hi-cut settings. These settings are accessed by pressing on the knobs on the ToneWood
  • Room Reverb with Decay, Pre-delay and Hi-cut settings
  • Plate Reverb with Decay, Pre-delay and Hi-cut settings
  • Delay with Speed, Feedback and Reverb. ( Note: you are not going to sound like the The Edge on the Skrydstrup switching system anytime soon with this)
  • Tremolo with Rate, Depth and Delay
  • Leslie style tremolo with rate, depth and reverb
  • Auto-Wah with Sensitivity, Envelope , Reverb
  • Overdrive with Drive, Filter and Reverb
  • DSP Bypass to mute the processor
  • Notch Filters to Notch Low and Notch High to filter based on the frequency

There is also the ability to save effect settings based on the tweaks you make which seems useful though I’ve not really played around with it.

I’ve largely played around with the Hall and Room effects for my purpos. You can tweak this plenty but I’d like to make sure I’m not sounding “wall of sound Spector-mode” on my Cordoba for every track.

All in all, a great addition to enhance the acoustic and more than anything else, the convenience factor is amazing. It’s much more easy to optimize practice time now without switching guitars or hooking up effects racks to my Ibanez for a 10-minute session. If you want more control over ambience and soundscapes with minimal setup or complexity, this is it.

I recorded a quick demo with the Hall Reverb with Decay and Hi-cut set to default and no audio edits off the iPhone camera. The audio needs to be enhanced and it doesn’t fully do justice to the ToneWood sound. The jam is me noodling on S&G’s cover of Anji by Davey Graham. The nylon strings don’t lend to much slack in bending at all but point was to capture a small moment of a few hours testing this wonderful amp.

Note – I don’t have any affiliation with ToneWood.

Alesis V49

Finally bit the bullet and added the Alesis v49 to my motley collection of instruments. 49 keys is enough for a novice like me. I’ve been near midi keyboards a lot when I actively played guitars for years but never really felt the inclination to own one. The piano & guitar combination is still my favourite duo when it comes to making music that feels good- think massive drum fills, shredding guitars with minor arpeggios, edgy bass, FM bells and a moody atmosphere and you got my code.

 The main goal here is to get better at programming accompaniments to instrumental guitar and to get better at arranging compositions.The 8 LED backlit pads respond OK though I haven’t really used them a lot. The sensitivity index on them seems different so it seems like a bit of bother to use them both especially for fast passages. The 4 assignable knobs are super convenient to program. I really like the Pitch and Mod wheels which let you wail so I can channel my inner Sherinian.

The 49 keys are full-sized and semi-weighted. Compared to a legit piano, they size up pretty well and feel great. The form factor is slightly more harder to press down if you do a direct comparison with a full-fledged digital keyboard but its not too far off. Alesis also allows you to alter the channel, transposition, octave and velocity curve for the keys – I did that immediately after unboxing as most of my earlier research suggested it best to fix that early before I got too comfortable with the “stiffness”.

Overall build quality seems solid. The 37-inch size of this workspace is where its appeal lies for me. I can easily place it on my workdesk without needing separate storage space for it.The package also comes with the Ableton Live Lite Alesis Edition & MIDI editor software. The activation and account creation steps were a breeze – firmware upgrade and I was good to go in 15 minutes.


Power Windows

Power Windows (1985) is the first Rush studio album I listened to and it remains my seminal Rush experience in the 80s Rush era (my other go-to’s are Hemispheres and Counterparts) . My perpetual fondness for this album is not based on any lurking nostalgia but for sheer prodigious musicianship and lyrical genius this album conveyed. Also, though my focus is more on the guitar wizardry, the virtuosity on the drums and bass together makes this album what it ultimately became.


An album forged during the height of the 80s synth boom, I’ve had numerous arguments over the years with other fans who (may rightfully) suggest this represents a low point after the grandeur of Moving Pictures/Permanent Waves or even the progressive heights of 2112 and Hemispheres.

The production quality is pristine with a landscape painted by every track that stands on its own right be it the polyrhythms of “Mystic Rhythms” or the 162 BPM synchronicity of “Manhattan Project”. The overall sound is produced and engineered to excellence.

Most rabid fans claim the CD’s re-issues are not in the same league as the vinyl ( which I don’t own ) but the remasters seem to do the original mercury recordings some justice. Incidentally, this was the first Rush album to ever be released directly to CD.

I’ve gone through a phase spending a lot of time replicating Alex’s 80s tone to varying degrees of satisfaction. Essentially they amounted to a lot of chorus and flanging delays, not ot mention tons of reverb. In some cases chaining multiple layers of chorus one over the other seemed to get the tone closer. Arguably all over the top as the 80s demanded. I plan to hopefully put up a guitar rig patch slightly closer to this tone.

Track Listing:

The Big Money (5:36) – Named after John Do Possos trilogy of the same name. A tribute to soul-less capitalism, monetary value and fame. The opener delivers a banging riff thanks to a full step tuned-up guitar and open chords with ringing harmonics. The 80s were big on racks and this was Alex on Rolands and TC Electronics racks as told to guitar magazines in that era. The live version in “A show of hands” is a worthy live companion. “

Grand Designs (5:05) – Another title from the John Do Possos trilogy. Deals with individualism and non-conformance to group-think. Being stuck in a two-dimensional life and part of the mass production scheme, it takes courage and tenacity to go against the grain. The focus on “image” in the 80s and the “form without substance” also led to a competing and overlapping music/bands that the era is known for. Classic Rush style with repetitive patterns with the drums churning out progressively more complicated parts. The Allan Holdsworth influence comes out in this track with more whammy work and sonic feedback across tonal centers creating an atmosphere towering over the synth barrage. The 7 phrase ending is another nod to the progressive roots.

Manhattan Project (5:05) – About the birth of the nuclear age with a poignant description of the time (WW2), a man (Oppenheimer) and a place ( Los Alamos). The mention of the “Enola Gay” that dropped the atomic bomb completes out the last chorus of this orchestral majesty. The powerful imagery is complemented by a barrage of synth in the foreground with the opening verse melding into a tension-filled chorus. The lyrics shine in sections that drop out bass and guitar in a rare departure from the usual arrangements.

Marathon (6:09) – More inspirational fare about pacing your life partly inspired by Ernest Hemingway’s quote, “In life, one must (first) last“. Set goals to achieve them but don’t burn out too fast. A sublime chorus is overshadowed by a bassline that sprints through the song and the song unveils a middle section in 7/4 that this song is renowned for. Ringing notes sustained by the whammy bar from Alex’s Signature Aurora kick off the song and the texture continues into a mesmerizing middle section leading into a majestic solo.

Territories (6:19) – about nationalism. Beautiful lyrics backed by modern post-punk pop style sound under a big rock foundation. The context should suit the current times well – better being proud of being a world citizen than the bloody pride of being associated with a flag that divides. The Ibanez HD-1000 rack provides the sonic delay that resonates throughout the track. The solo or lack of a true one is understated and the song does well without requiring more histrionics to distract from the lyrics.

Middletown Dreams (5:15) – Similar themes to the suburban disillusion of Subdivisions from the Signals era. The power of dreams and ability to challenge your current environment to achieve those dreams. This excerpt sums it the best. The lyrics probably resonate the most of this album with me as an immigrant and sometimes stranger in a strange land (“Dreams transport the ones who need to get out of town”). Musically, the track ups the ante with more synths and a tempo change in the middle section and shifts a key. The synth and multi-tap delays create some excellent passages making way for the vocals and a busy bassline and a grand chorus. The sequencer in the middle around the 2 minute mark does get a little tiresome especially after all the space in the previous passages but that’s a minor blip.

Emotion Detector (5:10) – Seems like not about anything particular but a bunch of messages meshed together. Key standout are lines like “Illusions are painfully shattered right where discovery starts”   – we have an illusion about who we really are. Probably the weakest track on the album – a bit too much veering to the pop side of the repertoire. The guitar tries in vain to save it with a brilliant solo accentuated by feedback and tasteful notes towards the climax of the solo. Guitar feedback in the beginning of the track washes you over with absolute sonic bliss until the synth authoritatively climbs all over it dampening it to a few notches lower. The vocals are a highlight and the standout. The synth drums have not aged well and sound a bit dated.

Mystic Rhythms (5:54) – A magnum opus to end the album. My interpretation is that this is about exploring our primal instinct about what behind the obvious and beyond and challenging our understanding about the universe. Surprisingly, this was an acquired taste for me and over the years I’ve grown to appreciate the musicianship and the poetry in this more. The guitar texture and the repetitive staccato patterns are the thread that keeps the song’s foundation as arpeggios add an air of sublime mystery to the track. Lots of vocal harmony and the imagery of the track takes you “under northern lights Or the African sun“. the guitar parts are understated but effective as they give way to layers of synth.

Despite the synth barrage and the guitar buried in the mix, the album reflects the times. The songwriting is just on another plane of existence and this evolution in their sound may probably the most accessible for the average fan if you can get past the 80s influence.

Sonic Pi

As a hobbyist musician for many years, it’s been a constant struggle to fuse the programming paradigm with musical ability. Without midi, it’s usually just a fruitless exercise trying to use some of the open source available. But with Sonic Pi ( and the power of a dynamically typed interpreted language like Ruby – this experience has just been getting better over the years. It took me less than 10 minutes to compose a piece of music (and in the process teach the inherent power of loops and iteration to my 6-year old this morning). A totally immersive experience with the power of meta-programming.

Results below ( used a tabla sample fused with e minor pentatonic piano loop in about 75 lines of code). If you use the software, consider donating to to keep SonicPi alive.