Friday 05/18/2018 by phishnet

FROM THE TAPERS' SECTION: PART 1 (4/2/98)

@wforwumbo applies machine learning to binaural hearing theory, and is putting the finishing touches on his doctorate in architectural acoustics this summer. His research focuses on the effects that a room has on performed music and how we perceive sound in space – he does so by building computational models that simulate and extend human hearing. He is also a classically-trained musician and an electrical engineer with a keen interest in digital audio signal processing; he designs and implements filters and transforms to manipulate audio, which he brings to his studio production and mixing engineering work. His obsession with audio doesn’t end there though, as he has recently ventured into the tapers’ section to record live music. Thankfully for us at Phish.net HQ, @wforwumbo is a huge fan of Phish and Phish.net, and has begun contributing to the site, both working to expand and improve the Jam Charts and helping to craft (and remix!) Mystery Jam Monday puzzles. Today, he will kick off a new regular blog series, “From the Tapers’ Section,” wherein he will draw from several different parts of his massive toolkit to not only bring Phish fans brand new mixes of audience recordings from classic Phish shows, but he’ll also share both his deep technical knowledge and discerning musical perspectives of the shows and the recordings thereof. - @ucpete


Drawing from my experience as both a live taper and a studio production engineer, I frequently manipulate my back catalog of live Phish tapes to my personal preference on reference listening systems. I have spent lots of time working with studio tools; it’s a labor of love, always trying to craft and sculpt sound - to let the tape get out of the way between me and the music. I do want to make one thing explicitly clear here: I am not the definitive voice. I am not touting that these are the “correct” way to listen to shows. I’m not even claiming that these will be preferable to your current tape of a show. Because at the end of the day, the sole rule of “good” audio is that only YOU can decide what sounds best. In fact, that’s the most important bit of advice I give to everyone when they ask me about audio: trust your ears. My tastes may not be the same as yours, and that’s okay - there’s plenty of room for all of us in the fan base.

Now with that being said, one intent of this taping series is to encourage the distribution and usage of audience-recorded tapes (“AUDs”). Tape trading has an incredibly rich and storied history, and is a large part of why many of us are into Phish. One of my favorite endeavors in digging through my catalog of tapes is comparing two different recordings and correlating their strengths and weaknesses to my personal preferences. This furthers my taping and production work by thinking about how to capture and manipulate sound, including the layouts, techniques, and gear that I use. To me, it’s lots of fun to think about and understand the intricacies of a given microphone and preamp, the recording location inside of a venue, or what experience I want from a tape (immersion? stereo image? frequency balance? more Mike? etc.). This blog series is in part an attempt to share my notes and thoughts on specific tapes to highlight different aspects of a show that you might not have heard before.

I am approaching this as a novel method for you to hear audience tapes in a new light with a refreshed perspective on what they are capable of, and allow you to decide if AUDs are truly for you. At the very least, I hope to introduce you to jams and shows from the back catalog that may fly under your radar; at best, I hope to share with you the wonderful and immersive world of AUD tapes.

The first tape we have is in honor of its recent 20th anniversary: 4/2/98, Island Tour night one. This is a show many of you are already intimately familiar with; it’s my personal favorite show from Island Tour, and it happens to fall smack dab in the middle of my favorite era of Phish (1996-2000). I’ve heard many of the tapes in distribution, including the LivePhish soundboard, countless times throughout the years – this particular recording is the one I keep returning to.

This 4/2/98 tape, created by Craig Hillwig, came onto my radar about a year ago. Craig focused his recording techniques on getting an accurate soundstage; after seeing countless Phish shows over the past 20+ years, he has an internal expectation of where the musicians should be located around his head during playback. His approach gives an extremely balanced and startlingly pleasant perspective of how things sounded in the room, from where his microphones were set up. Craig, like myself currently, was a member of “Team Schoeps” using the Schoeps Colette system of small diaphragm condensers; he has since retired from the taping circuit, though he kindly offers his wisdom on sound to me on a nearly-daily basis. For this show specifically, he used a pair of mk41 supercardioid microphones, which are highly directional and help to cut down on both audience chatter and room reflections, but don’t exhibit the same bass response as less-directional microphones. What this means practically is that you get less of the low-end thump from Mike’s bass and Fish’s kick, but you also have a clearer stereo image of the recording and significantly reduced audience chatter - with crisp and accurate transient response on the whack of Fish’s snare, the air of Fish’s cymbals, the pick attack of Trey’s guitar, and the top end of Page’s piano.

In Craig’s own words: “From what I remember, the official tapers’ section was on the floor, I remember there was a roughly 10-15 foot buffer of open floor between the front of a three-sided cage and the soundboard riser. I got into the venue later than I wanted to; I found someone I knew in the front row of the tapers’ section and clamped onto them. Since I was late to the venue I was the lowest mic pair on the stand, so my microphones were maybe 7 to 8 feet off the ground, tops. I started with 103 degrees and 10 inches between the mics, then I narrowed it down to roughly 90 degrees based on sight lines and intuition. Whatever that resultant spacing was is what I went with; let’s call it DIN [editor’s note: DIN, an old German radio standard, refers to 20 cm spacing and 90 degree angling between microphones]. From listening to the raw files afterwards I suspect that the stand was off-center, slightly stage left.”

There are a number of features about this specific tape that make it my favorite recording of 4/2/98. All instruments are presented with a solid soundstage: each band member is easily separable from his bandmates in the stereo image. When I close my eyes, I can hear Page hard left, with Trey just to his right, Mike approaching center, and Fishman filling out the center and right side of the image. This separation is further enhanced in the frequency spectrum where individual instruments do not bleed into each other, instead remaining crisp and distinct. The band used lots of stereo effects in this show, as evidenced in the “Twist”’s official soundboard - Page had a stereo tremolo on both his Rhodes and his synthesizer, and Trey had multiple passages of his rotary speaker. In Craig’s mk41 tape, this mixes very pleasantly with the room effects to create a listening experience that pulls you out of the tape and drops you right into the room on that cool spring evening in Nassau County two decades ago...

The first set bursts out of the gates with a groovy and funky eight-and-a-half minute “Tube” that competes with some of the song’s Fall ‘97 outings, but the real gem of this first set is “Stash.” This “Stash” climbs like the fiery ‘94 versions, but instead of breaking back to the main riff to end the song, Phish instead opts for bliss jamming in A mixolydian, throwing their cow funk skills at the tune and proving that the jam style could drop at any time, in any song. The “Chalk Dust Torture” that ends this set is high-energy and serves as an exclamation point on the first of the eight sets from this mini tour while still leaving everybody wanting more.


Phish | Thursday April 2nd, 1998 | Nassau Veterans Memorial Coliseum | Uniondale, NY
Set 1: Tube, My Mind's Got a Mind of its Own, The Sloth, NICU, Stash > Horn > Waste > Chalk Dust Torture
Set 2: Punch You In the Eye > Simple > Birds of a Feather, Wolfman's BrotherSneakin' Sally Through the AlleyFrankie Says > Twist > Sleeping Monkey > Rocky Top
Encore: Guyute

This show marked the debut of Birds of a Feather and Frankie Says. After NICU, Trey commented on the brief “Island Tour,” remarking that the band was getting bored at home and wanted to play some shows. Stash was unfinished and contained Frankie Says quotes at its end. The final chord of Chalk Dust included a "Charge!" tease from Page. Fikus was teased by Fish before Wolfman's. Sneakin' Sally did not contain a vocal jam. Twist included Star Trek theme teases from Mike. This show is available as an archival release on LivePhish.com.


The second set kicks off with a solid (albeit straightforward) “Punch You In The Eye” that yields to a breathtaking “Simple.” The opening pairing of the second set leaves the band loose and ready to continue their exploration. To provide some context for the few fans that may be unfamiliar with this historic run, the band had been hard at work in the studio working on Story of the Ghost, and they were anxious to share the fruits of their labor with the fans. The next 50+ minutes of the second set feature a mix of promising debuts and some cathartic jamming: after a solid debut of “Birds of a Feather,” they jump right into the funky end of the pool with “Wolfman’s Brother” → “Sneakin’ Sally through the Alley” → “Frankie Says,” the latter being another new tune debuted in this set. Alas, these were just table setters for the evening’s finest offering: “Twist.”

It’s hard for me to decide where to start on this “Twist.” It’s cerebral and effortless – a super slick groove. It’s a clear and marked evolution from the thicker cow funk grooves of ‘97, finding spacier pastures on the back of Page’s Rhodes and synths and Trey’s Leslie speaker. At the 6:28 mark, the band takes a deliberate step away from the G Dorian vamp typical of Type I “Twist” jams (G-Bb-C-D – the main “Twist” theme) and jumps headfirst into a faster, darker G-based groove, which Mike uses as a springboard to lead the band into Bb. Trey and Page play around with the mode, with Page eventually settling on Bb mixolydian.

This is a curious choice, because the Bb analog of G Dorian would be Bb lydian, but the seemingly insignificant mode switch to Bb mixolydian completely shifts the modal tonic and root of the composition. Lydian would give a more Byzantine or Arabian feel to the groove, but mixolydian lends itself more readily to bliss jamming; the band opts for the latter. You can hear this tension play out and eventually resolve from 7:17-7:33, when Page plays an Eb as opposed to an E to complete the mode shift. Despite the foundational change to the jam, it isn’t the slightest bit jarring – Trey immediately picks up on what Page is playing and follows his lead. Mike and Fishman lock down a steady groove that allows the melody to stretch its legs, and the jam propels itself toward the stars. This yields to an extremely patient, careful, detailed, and gorgeous passage of music.


NOTE: per @wforwumbo's comment, the SoundCloud link is provided here for convenience, but given their own proprietary (and general purpose) compression algorithms should not be used to judge overall quality.

The next segment of this “Twist” jam contains the most standout feature of this tape to me – it’s what makes it my favorite tape by a sizable margin over others. Listen to the segment starting at the 10:52 mark, where Trey accentuates his pick scratches with his wah pedal. Prior to listening to this tape, I always assumed Trey just wanted to add rhythmic complexity to Fish’s locked-down pattern to generate polyrhythms. But on this tape I hear and interpret Trey using the wah pedal to tune his scratches to different resonances in the room, allowing them to hang around the audience’s head and further push your perspective out of the tape, into the psychedelic wormhole he created in the room that evening. Craig’s tape is the only source I have ever been able to hear this, with an amazingly refined level of detail and clarity.

Page and Trey continue using a slew of stereo effects throughout, producing a truly immersive, ethereal experience. Eventually the band settles into a “Riverport Gin”-esque riff that provides the final view from above, before giving way to dissonant and chaotic noise that simmers down into a murkier swamp that almost begs for a deep “2001.” Alas, they settle on the classic encore pairing of “Sleeping Monkey” > “Rocky Top” to finish the set, before bringing out the ugly pig for a “Guyute” encore.

The tape is not perfect, both as it stood in its raw form and in my remaster of it - my own caveat emptor, if I may. The stereo image sounds shifted towards the left, likely a function of the mic stand being stage left. This is a consistent challenge tapers have to face: we don’t always have the luxury of setting up precisely where we’d want to, so we make do with the hand we are dealt when we arrive at the venue and set up accordingly. There is a lack of Mike on this tape which is a function of using supercardioid microphones. This is compounded by the fact that the capsules picked up a small amount of what I call “room mud,” which causes bass and some guitar tones to sound a bit washy and undefined at times. And finally, the mk41 capsule has a characteristic upper-midrange spike which causes piano, sharp attacks on guitar, and cymbals to have a slightly “shout-y” quality to them.

All of these factors contributed to how I approached post-production work on this tape. I applied some extremely mild panning to try to counterbalance the fact that the stand was off-center, and that one channel was consistently louder than the other. In equalization, the easiest and most obvious change to make was to bring Mike further up in the mix. Here, a careful balance has to be struck, as bringing Mike further up also increases the dreaded “room mud.” I found where the room mud was worst and was able to isolate it from the rest of the mix by bringing down a specific frequency region by just a few dB; this was done by ear to “clear the haze” without ruining the careful balance of instruments. Next, I dealt with that characteristic mk41 upper-mid spike; I found the resonant spot and pulled it down accordingly. This helped to further stabilize the stereo image, while also allowing the midrange to breathe without as much resonance. As a final touch, I raised the treble just a touch in order to allow the air around Fish’s cymbals to breathe and shine through with ease and refinement.

This process was a challenging one to organize, as the decisions I outlined can tend toward an overall “scooped” signature, where the high and low ends dominate. This can cause recordings to sound a bit hollow and lacking in the meat-and-potatoes of rock music: the midrange. The key here was moderation - I had to make my edits aggressive enough to accomplish the task at hand without making any one change overly noticeable. In Craig’s own words, when he compared his original raw files with my edits: “this mix certainly delivers in terms of loudness with no obvious loss of headroom, and the EQ seems pretty tasteful in that I can’t really point to any one thing as the difference but the result is overall more pleasing.”

A quick note about the file sets for those of you grabbing these: a common technique used in production is audio compression. This reduces the dynamic range of a recording by making the loudest portions of the waveform quieter, and allows the overall volume to be raised without inducing clipping. One reason I love AUD tapes is that they preserve the details - the subtlety between quiet and loud - with pristine quality, and often remain uncompressed to give you the full dynamic range of the original performance. For the FLAC file sets, I did not touch this tape at all with any sort of compression; I wanted to preserve the detail and subtlety of every nuance of this tape. However, for the mp3 file set I have added some very mild studio compression techniques in order to raise the overall volume just a bit, expecting many of you to use the mp3 version on your phones, tablets, and other mobile devices where space is a premium and fidelity isn’t a luxury to be afforded. I recommend that you judge the mix on a decent sound system or pair of headphones you know well with the FLAC file sets, however the mp3 files should still sound quite good for your on-the-go cloud library with inexpensive earbuds.

I leave you here to spin the tapes at your leisure. I recommend you hit the play button and just get lost in this gorgeous music. Until next time, everyone!


FLAC and MP3 file sets can be found at this link (Google Drive): DOWNLOAD HERE

If you liked this blog post, one way you could "like" it is to make a donation to The Mockingbird Foundation, the sponsor of Phish.net. Support music education for children, and you just might change the world.


Comments

, comment by Mshow96
Mshow96 This is fantastic! Thanks @wforwumbo! Such a great show to start with. I can't wait to give this a spin and I look forward to more installments in this series.
, comment by Wombat_en_Fuego
Wombat_en_Fuego Wow. I feel a tad bit smarter just because of reading this. I am so clueless about music (keys, methods of taping, etc.), so I love reading this stuff simply to gain some appreciation for what the community does for us. I always assumed the tapers' section was just a bunch of dudes putting microphones in the air. Boy, was I wrong, and gladly so.
, comment by wforwumbo
wforwumbo @Wombat_en_Fuego said:
Wow. I feel a tad bit smarter just because of reading this. I am so clueless about music (keys, methods of taping, etc.), so I love reading this stuff simply to gain some appreciation for what the community does for us. I always assumed the tapers' section was just a bunch of dudes putting microphones in the air. Boy, was I wrong, and gladly so.
Glad to discuss any and all of the things contained within this post (and more!) in-depth. Give me the time of day and I'll keep ranting on and on about Phish and why I love the music so much. Though again, I want to highlight I'm not necessarily correct - these are just my thoughts and notes, open for critique and discussion.

Taping for me is part science, part art - I have the science side down, and I'm actively developing the art of taping. One reason I called out Craig in this post, is he's been teaching me LOTS about taping as an art form and how to use intuition rather than equations to dictate taping methods, though he isn't the only one to do so (hint hint - stay posted for the second installment in this series!). We tend to be a pretty friendly bunch, so long as you respect our (admittedly scarily expensive) gear, silence, and dancing space in the section while we're trying to record the show.

We all want to provide a service to the fanbase and produce stellar recordings for you, the community at large, to enjoy.
, comment by wforwumbo
wforwumbo Oh, and a note for all of you out there - the soundcloud link, while definitely convenient, applied an extra layer of both dynamic range and data compression to the file set, which to me is highly audible; feel free to listen there, but please do not judge the quality or depth of the recording or remix/master based on the soundcloud link.
, comment by Gutbucket
Gutbucket Excellent writeup, which encouraged me to register at phish.net just today (having followed the evolution of the band since '91). Will be keeping my ear to the rail for your future posts here!

~a random taper
, comment by TheHeadsChoice
TheHeadsChoice I love everything about this. please do more of these writeups!!
, comment by Wombat_en_Fuego
Wombat_en_Fuego @wforwumbo said:
@Wombat_en_Fuego said:
Wow. I feel a tad bit smarter just because of reading this. I am so clueless about music (keys, methods of taping, etc.), so I love reading this stuff simply to gain some appreciation for what the community does for us. I always assumed the tapers' section was just a bunch of dudes putting microphones in the air. Boy, was I wrong, and gladly so.
Glad to discuss any and all of the things contained within this post (and more!) in-depth. Give me the time of day and I'll keep ranting on and on about Phish and why I love the music so much. Though again, I want to highlight I'm not necessarily correct - these are just my thoughts and notes, open for critique and discussion.

Taping for me is part science, part art - I have the science side down, and I'm actively developing the art of taping. One reason I called out Craig in this post, is he's been teaching me LOTS about taping as an art form and how to use intuition rather than equations to dictate taping methods, though he isn't the only one to do so (hint hint - stay posted for the second installment in this series!). We tend to be a pretty friendly bunch, so long as you respect our (admittedly scarily expensive) gear, silence, and dancing space in the section while we're trying to record the show.

We all want to provide a service to the fanbase and produce stellar recordings for you, the community at large, to enjoy.
I absolutely love your passion for it. I feel like such an idiot when I can't "discern" the start of Maze from Bowie or the start of Rift from Scent. I can listen to them against each other a thousand times and I still get it wrong live. I also can't seem to hear teases unless they are super obvious. And I'm not exactly new to Phish, as I've been listening since '97. How you all can talk about it how you do amazes me, and I love hearing/reading it. I will definitely look for more future installments!
, comment by mdphunk
mdphunk This is great! I've been frustrated for years with "remasters" of tapes that circulate with no info at all regarding what was done the tape to improve sound (and often achieve these results using compression or limiting, as far as I can tell).

Would you be willing to share what frequencies you cut, or are you trying to keep that as your own "secret sauce"?
, comment by wforwumbo
wforwumbo @Wombat_en_Fuego said:
@wforwumbo said:
@Wombat_en_Fuego said:
Wow. I feel a tad bit smarter just because of reading this. I am so clueless about music (keys, methods of taping, etc.), so I love reading this stuff simply to gain some appreciation for what the community does for us. I always assumed the tapers' section was just a bunch of dudes putting microphones in the air. Boy, was I wrong, and gladly so.
Glad to discuss any and all of the things contained within this post (and more!) in-depth. Give me the time of day and I'll keep ranting on and on about Phish and why I love the music so much. Though again, I want to highlight I'm not necessarily correct - these are just my thoughts and notes, open for critique and discussion.

Taping for me is part science, part art - I have the science side down, and I'm actively developing the art of taping. One reason I called out Craig in this post, is he's been teaching me LOTS about taping as an art form and how to use intuition rather than equations to dictate taping methods, though he isn't the only one to do so (hint hint - stay posted for the second installment in this series!). We tend to be a pretty friendly bunch, so long as you respect our (admittedly scarily expensive) gear, silence, and dancing space in the section while we're trying to record the show.

We all want to provide a service to the fanbase and produce stellar recordings for you, the community at large, to enjoy.
I absolutely love your passion for it. I feel like such an idiot when I can't "discern" the start of Maze from Bowie or the start of Rift from Scent. I can listen to them against each other a thousand times and I still get it wrong live. I also can't seem to hear teases unless they are super obvious. And I'm not exactly new to Phish, as I've been listening since '97. How you all can talk about it how you do amazes me, and I love hearing/reading it. I will definitely look for more future installments!
There’s a quote from one of my favorite tv series, 30 Rock. Tracy Morgan asks Alec Baldwin: “you like Phil Collins?” To which Baldwin responds with “I have two ears and a heart, don’t I?” My opinions on Phil Collins’ music non-withstanding, this succinctly summarizes how I feel about the greater picture of Phish’s music. We can try to intellectualize it as much as humanly possible - and I fear much of what I write may end up coming across as such, which really isn’t my intent - but at the end of the day, we all love this band and the music. The jams make us *feel* a certain way, and that feeling and experience are unique to every single one of us. And that’s one of a number of things that brings us together, is the fact that despite our difference in perception and experience, we are all still here at the end of the day for the music. Some of my writing is an attempt to explain how I feel, and correlate anything I can to why I feel the way I do when I spin Phish jams. But that doesn’t make me any smarter or dumber than anyone else that’s also into this band. You LOVE this band, and at the end of the day that’s all that matters.

To quote a group consuming *lots* of my stereo time for the past few months, the Dead: “If you get confused, listen to the music play!”
, comment by wforwumbo
wforwumbo @mdphunk said:
This is great! I've been frustrated for years with "remasters" of tapes that circulate with no info at all regarding what was done the tape to improve sound (and often achieve these results using compression or limiting, as far as I can tell).

Would you be willing to share what frequencies you cut, or are you trying to keep that as your own "secret sauce"?
I *could* share them, but I don’t feel that will help much. What works for this tape, won’t work for another. I do everything by ear, based on my experience as a producer and mixing engineer. My fear if I explicitly state my settings is that people would use the same values I did here, and try to apply that to every tape which is 100% the wrong way to go about it. That might contribute to EQ jobs I feel don’t actually improve the tape. That’s one of my top criteria when doing work on tapes: if my end product doesn’t sound better to my ear than the original, leave it untouched as-is.

The best advice I can give you is to practice on your own, mix and EQ as much as you possibly can. Learn what tools work best for you in different environments and workflows. Like I said in the blog post: trust your ears, let them guide you and the end product will benefit in the long run. There will be lots of trial and error, especially as you make mistakes, but that’s how we learn.

I couldn’t distill my experience in mixing and producing succinctly enough for a blog comment, or even a blog post - it would take years of hands-on demonstration to show you how I approach mixing. Which I am not opposed to, but limited time sadly restricts me from being able to do this.
, comment by Capt_Tweezerpants
Capt_Tweezerpants Great writeup, especially the part about the pick scratches in Twist. I'm listening to around 10:30 to 13:30 over and over on the LivePhish version and the wumbo version. Looking forward to this blog series!
, comment by mcgrupp81
mcgrupp81 Thank You @wforwumbo 4/2/98 Twist was one of the first Phish jams I became obsessed with. For a few months, I would play it as I fell asleep. When collecting, I only thought in terms of the microphones (Schoeps, Neumann, AKG) but, obviously, there is a lot more that goes into the final product. I appreciate your efforts. SBD is great, but if you truly want to replicate the feel of a show, you have to play a solid AUD.
, comment by GrantBrown
GrantBrown Thanks @wforwumbo for your work on this. Acoustics is a hobby of mine also. I'd like to mention that after years of tinkering with playback equipment and setups, using a minimum-phase response resampler has made the biggest difference in terms of warmth and authenticity. Any thoughts from you (and others) about this topic? By the way, for anyone interested, Foobar 's SOX resampler has a minimum phase setting, which is what I use. Thanks.
, comment by CleverRuse
CleverRuse @wforwumbo

Interested in the machine learning aspect of your research - will you be writing and pieces on that in the future? Thanks for the interesting read.
, comment by wforwumbo
wforwumbo @mcgrupp81 said:
Thank You @wforwumbo 4/2/98 Twist was one of the first Phish jams I became obsessed with. For a few months, I would play it as I fell asleep. When collecting, I only thought in terms of the microphones (Schoeps, Neumann, AKG) but, obviously, there is a lot more that goes into the final product. I appreciate your efforts. SBD is great, but if you truly want to replicate the feel of a show, you have to play a solid AUD.
The three most important factors of ANY recording, in the studio or in live taping: location, location, and location. There are MANY different tapes I’ve heard from the same venue with the same microphone capsules (granted the downstream preamps/converters also impact the end product...) in different spots and they sound radically different. There’s more to a tape than just the mic brand.

In the studio, I’ve made great recordings with just a pair of cheap beat-up SM57s, and recordings I wasn’t happy with using AKG 414s. The price disparity is huge, but it’s all about where you stick the microphone at the end of the day.
, comment by wforwumbo
wforwumbo @GrantBrown said:
Thanks @wforwumbo for your work on this. Acoustics is a hobby of mine also. I'd like to mention that after years of tinkering with playback equipment and setups, using a minimum-phase response resampler has made the biggest difference in terms of warmth and authenticity. Any thoughts from you (and others) about this topic? By the way, for anyone interested, Foobar 's SOX resampler has a minimum phase setting, which is what I use. Thanks.
Yes I can talk about resampling quite a bit, given my bread-and-butter is audio DSP.

Before digging into that, a brief note - there are two types of approaches to designing digital filters and layouts: finite impulse response (FIR) and infinite impulse response (IIR). FIR when designed right gives you a linear phase distortion, with the downside being that by nature of its design it requires additional computation power and induces an inherent lag into your signal path (which is fine for post or offline work, but for things like live mixing or trying to actively change parameters on the fly during tracking/mixing can prove problematic). IIR filters are immediate in their response, however it is impossible to generate a truly linear phase response with them; so we instead design systems that mitigate the phase distortion - so-called “minimum phase systems”.

Why do we care about this? Let’s analyze what I mean by “distorting the phase” first. Going back to basic waves, envision a sine wave for a moment. Clean, starts with value 0 at time t=0 and completing its cycle in some period T, extending (for all intents and purposes, for analysis at the periodic cycle from 0->T) infinitely long in either direction. If we have a system that allows it through with no attenuation or gain, but shift its phase in either direction and then add it back to the initial sine wave, we get destructive interference. Which is all fine and dandy if you have just a single tone you are analyzing because you can compensate for that delay, but in IIR systems the phase distorts in a non-linear fashion across different frequencies, making it impossible to correctly compensate across the board. This is what we call “phase distortion” and can affect things such as stereo imaging and will additionally produce a comb filter effect in the frequency magnitude.

For filters in particular, we additionally analyze something called “group delay,” which is computed by taking the negative derivative of the phase of the system. From this we can analyze how the filter will respond to different tones in the steady state (long, sustained vowel tones). Accordingly, we can also compute an approximation of an idealized de-warping filter to compensate for phase distortion, however those de-warping filters will induce inherent lag and will never truly de-warp the phase fully. Likewise, for impulsive sounds (drums, or the pluck of a guitar string, for example), all transients get smeared non-linearly by this system and the attack sounds both softened by the spread-out and decorrelated phase; it’s possible to try and fix this but I’ve yet to hear any minimum phase algorithm that gets anywhere close.

Resampling as a practice isn’t usually something I recommend. Depending on the conversion process and calculations used (for audio, sigma-delta is usually the best), there is always an inherent Gaussian error induced in the signal. Basically, you are trying to approximate information that wasn’t there to begin with, and it’s very rarely going to be 100% accurate for real signals that aren’t pure sines or 100% linear functions (which, I’d note, sines and cosines are not linear). So then why do it? Well there are actually sometimes benefits to doing so. For one thing, output converters are usually for cost reasons designed to be optimized at a very specific sampling frequency. They have reduced “jitter” (basically, how far they deviate from being on time - which if not true can induce further phase distortion) at these specific sample rates. For another, digital filters will be more accurate in their computations when the sample rate is higher. This can produce a perceived “better sound”.

At the end of the day there’s no right answer. Trust your ears and do what you think sounds best when listening.
, comment by wforwumbo
wforwumbo @CleverRuse said:
@wforwumbo

Interested in the machine learning aspect of your research - will you be writing and pieces on that in the future? Thanks for the interesting read.
I’m happy to discuss that, but feel it’s not in the scope of the topics at hand here. Drop me a PM and I’ll happily discuss and answer questions privately. Same goes for everyone on here that’s interested in what I’m doing with my doctoral dissertation/research.
, comment by breslinp
breslinp This looks to be a great series. Thanks so much for taking the time to write this up. Do you have a good resource for musical theory such as when you write "A mixolydian". I've seen you write this on reddit and Anatomy of a Jam on Youtube uses it too. I did google it and a bunch of sites turn up. Do you have favorite?
, comment by chillwig
chillwig actual footage of @wforwumbo judging my audience tapes

, comment by StanleeMouse
StanleeMouse This is wonderful THANK YOU and I thought the Island couldn't dO more for entertaining. I really look forward to future releases. This island tour was one of the better runs I experienced... Great start THANKS AGAIN...
, comment by wforwumbo
wforwumbo @breslinp said:
This looks to be a great series. Thanks so much for taking the time to write this up. Do you have a good resource for musical theory such as when you write "A mixolydian". I've seen you write this on reddit and Anatomy of a Jam on Youtube uses it too. I did google it and a bunch of sites turn up. Do you have favorite?
What you are seeking, is a writeup on musical modes. It can be a bit daunting, but the wikipedia page on modes is a semi-decent overview.

Part of the problem that comes with understanding modes, is you really need to hear and then play them to understand what they’re all about. I learned about modes in an advanced music theory course on tonal harmonic modulation, where we all had to be constantly writing new music on our respective instruments to demonstrate understanding of them; and even still, I didnt really “get” modes until I started playing in lots of bands, especially jazz bands.

So the best resource I think, given it’s been my personal experience with them, is to learn them as scales on your instrument of choice and then playing with other jazz musicians. Because music theory means very little without the context of using the tools in a theory “toolkit” so to speak.
, comment by djphrayz
djphrayz Great job, wforwumbo! Not only do you carefully articulate and share your knowledge depth, but you do so with an approachable tone, which is awesome. I look forward to future installments, and I hope our taping paths will cross again someday! Also, that's quite an accomplishment you did there.. getting gutbucket to register a phish.net account just to give you kudos! Keep up the great work!
, comment by jmitchell
jmitchell @mdphunk said:
This is great! I've been frustrated for years with "remasters" of tapes that circulate with no info at all regarding what was done the tape to improve sound (and often achieve these results using compression or limiting, as far as I can tell).

Would you be willing to share what frequencies you cut, or are you trying to keep that as your own "secret sauce"?
Are there any particular shows or sources you are curious about? I know the transfers that I do, I don't alter anything at all. I may normalize and adjust if the recording was made with emphasis, but that would be it. The fellow that I work with on the transfers has the same approach. The idea is that what was captured is what should be presented.
You must be logged in to post a comment.
Support Phish.net & MBIRD
Phish News
Subscribe to Phish-News for exclusive info while on tour!


Phish.net

Phish.net is a non-commercial project run by Phish fans and for Phish fans under the auspices of the all-volunteer, non-profit Mockingbird Foundation.

This project serves to compile, preserve, and protect encyclopedic information about Phish and their music.

Credits | Terms Of Use | Legal

© 1990-2018  The Mockingbird Foundation, Inc. | Hosted by End Point Corporation