Become a Site Supporter and Never see Ads again!

Author Topic: Improved PAS technique - better imaging with good clarity  (Read 44829 times)

0 Members and 2 Guests are viewing this topic.

Offline fobstl

  • Trade Count: (4)
  • Taperssection All-Star
  • ****
  • Posts: 1629
Wow Gut, this new chart is awesome. Thanks for taking the time to put it together! I look forward to trying the PAS method moving forward.

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (15)
  • Needs to get out more...
  • *****
  • Posts: 15698
  • Gender: Male
  • "Better to love music than respect it" ~Stravinsky
Hey, I hope it helps!

A few comments on the previous revised table which I removed, and the new one-
The only thing the older table included which the new one does not was a choice between four different Stereo Recording Angles (SRA's) for each PAS angle.  The four choices provided were SRA = PAS angle -10°, SRA = PAS angle , SRA = PAS angle +10°, and SRA = PAS angle +20°.   Solving for each of these was acknowledgement of what I see as the primary subjective variable of the Improved PAS method and of the Stereo Zoom itself (as mentioned by Michael Williams in the paper)- What is the most appropriate SRA?. I originally included the four choices so that after using Improved PAS a number of times and trying those different variations, folks could home in on their prefered PAS SRA.  My thinking being that after a while we may be able to come to a consensus on which is most prefered.  But taping isn't some rigorous methodical scientific study and I realized it's just not realistic to expect much reporting back of which SRA option folks used along with how they felt about the imaging derived from it, much less reach any general consensus.

So for this table I just solved for SRA = PAS angle +10° for all entries (approximately, with a tolerance of ~ +/- 1°).  This is what Williams suggests as probably most appropriate for orchestra sources, is what I suspect is close to optimal for PA taper recording, is sort of the intent behind pointing-just-outside-of-stacks (although generally not what that really does, which is partly the reason for doing all this), and was the suggested starting point in the old table represented by the highlighted row entries.

A few implications of SRA = PAS angle +10° are-
The microphone spacing for any given PAS angle are slightly narrower than they would be for SRA = PAS angle.  Improved PAS tends to suggest spacings much wider than tapers generally use for traditional PAS, so a slight reduction in suggested setup spacing is probably a good thing in a practical sense.  It's difficult enough setting up wider spacings to begin with, and I suspect the spacings Improved PAS suggests may seem overly wide to many tapers simply because they differ from the traditional norm.  In defense of the wider spacings, I'll stay that most common near-spaced setups (ORTF, DIN, DINa, NOS) etc fall within a range close to what the SZ suggests, and by extension what the Improved PAS method suggests.  What is difficult for some tapers to accept is the basic implication that narrower angles between microphones require wider microphone spacings to compensate, or rather the extent to which that relationship pushes the configuration wider rapidly as the angle grows smaller.

Another interesting implication can be seen by looking at the fig-8 column.  Note that "Standard Blumlein" (fig-8's @ 90° / 0 cm) isn't represented there.  Instead, the coincident fig-8 arrangement occurs at PAS angle = 80°  (and this tends to correlate with my own experience running Blumlein from an audience perspective).  Narrower PAS angles between microphones begin to push the fig-8 microphones further apart, but less so than any other pattern. Since many tapers are constrained to using relatively narrow mic bars, either by the equipment they have on hand or by setup constraints, it may be advantageous to consider using figure-8s in Improved PAS.  Not only do fig-8's tend to sound "natural" (somewhat in a similar way to omnis, not falling into what I sometimes call the "cardioid compromise"), they include a "built-in low-cut" as a result of their bi-directionality which will be appropriate for many indoor AUD situations.  Break out your old LD's which have a switchable 8 position and give it a try.

Back to the SRA = PAS angle +10° thing- Anyone using this table and wishing to experiment further and tweak the method, can do the following (quoting myself from one of the earlier explanatory posts in the thread)-

Tweak it to your liking if you want- Play it back and listen.  If you prefer a more narrow-image presentation with the on-stage and PA sound more tightly grouped in the middle between the speakers, use a slightly narrower microphone spacing next time (which corresponds to a wider SRA squeezing more between the speakers on playback).  If you’d prefer a wider-image presentation, use a wider microphone spacing the next time (narrower SRA stretching things out to the width between speakers).  Once you determine your personal preference you can use this table as a guide to get close then bump the spacing one way or the other as you like.
^
If anyone reading this does that a few times and ends up finding a consistent preference for modifying the suggested spacing in a particular direction, please let me know.
« Last Edit: January 29, 2019, 02:31:03 PM by Gutbucket »
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (15)
  • Needs to get out more...
  • *****
  • Posts: 15698
  • Gender: Male
  • "Better to love music than respect it" ~Stravinsky
Oops, brain fart.  Minor detail but perhaps, but will revise the chart and repost it, removing the ORTF reference.  The non-highlighted box is not close to ORTF (110º / 17cm).. I somehow saw 7cm, thought ORTF and added that last-minute.

[Edit- corrected table now posted.  Apologies to the 18 of you who already viewed/downloaded since last night]
« Last Edit: December 13, 2018, 01:56:46 PM by Gutbucket »
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (15)
  • Needs to get out more...
  • *****
  • Posts: 15698
  • Gender: Male
  • "Better to love music than respect it" ~Stravinsky
Noah, Stereo Zoom data isn't available for the Schoeps mk22 "open cardioid" pattern specifically.  Yet since it's pattern falls somewhere between cardioid and subcardioid, so should the optimal spacing for a pair of them in PAS.  So with regards to applying the Improved PAS technique to your mk22's, you can at least use the new table to determine the appropriate range of spacings, fine-tuning from there by ear.
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline noahbickart

  • phishrabbi
  • Site Supporter
  • Trade Count: (33)
  • Needs to get out more...
  • *
  • Posts: 2554
  • Gender: Male
  • So now I wander over grounds of light...
Noah, Stereo Zoom data isn't available for the Schoeps mk22 "open cardioid" pattern specifically.  Yet since it's pattern falls somewhere between cardioid and subcardioid, so should the optimal spacing for a pair of them in PAS.  So with regards to applying the Improved PAS technique to your mk22's, you can at least use the new table to determine the appropriate range of spacings, fine-tuning from there by ear.


Thanks so much. If only schoeps made a mk22v capsule, my 50cm Bar would be perfect.
Recording:
Capsules: Schoeps mk41v (x2), mk22 (x2), mk3 (x2), mk21 & mk8
Cables: 2x nbob KCY, 1 pair nbob actives, GAKables 10' & 20' 6-channel snakes, Darktrain 2 & 4 channel KCY and mini xlr extensions:
Preamps:    Schoeps VMS 02iub, Naiant IPA, Sound Devices Mixpre6 I
Recorders: Sound Devices Mixpre6 I, Sony PCM m10

Home Playback: Mac Mini> Mytek Brooklyn+> McIntosh MC162> Eminent Tech LFT-16; Musical Fidelity xCan v2> Hifiman HE-4XX / Beyerdynamic DT880

Office Playback: iMac> Grace m903> AKG k701 / Hifiman HE-400

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (15)
  • Needs to get out more...
  • *****
  • Posts: 15698
  • Gender: Male
  • "Better to love music than respect it" ~Stravinsky
I *always* run a pair of mk22 no matter what.

Do you have a standard way of positioning them? I just got a pair of Neumann KM143's, their Wide Cardioid condensers, and have only used them a few times, and all but once, on stage. Very interested in practical experience with the Hypocardioid (!) pattern!!

I try to use the PAS theory with them. I've found that a 35cm spread at 70 degrees tends to work well from the OTS at MSG. FOB, I've used them with a NOS setup with good results. Onstage I've used them at 21cm and 110 degrees.

Basically apply the stereophonic zoom, knowing that you'll always want a little wider spacing than regular cardioids.

I just checked the figures Noah states above against those suggested in new table.  Indeed, the values fall pretty much in line with either the cardioid or subcardioid range.  Might want to try a touch more space between them next time at MSG if easily doable.

Edit- Noah, I just remembered you are using a dedicated-width bar, so probably not easily doable without a new bar.
« Last Edit: December 07, 2018, 03:04:49 PM by Gutbucket »
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline Chuck

  • Trade Count: (42)
  • Needs to get out more...
  • *****
  • Posts: 10810
  • Gender: Male
  • time between the notes...
    • My recordings on the LMA
I just read this thread. Here is a phone app that may be useful for this application.

https://play.google.com/store/apps/details?id=air.com.neumann.recordingtools
Reality is merely an illusion, albeit a very persistent one.

Microphones: AKG C 480 B comb-ULS/ CK 61/ CK 63, Sennheiser MKE 2 elements,  Audix M1290-o, Micro capsule active cables w/ Naiant PFA's, Naiant MSH-1O, Naiant AKG Active cables, Church CA-11 (cardioid), (1) Nady SCM-1000 (mod)
Pre-amps: Naiant littlebox, Naiant littlekit v2.0, BM2p+ Edirol UA-5, Church STC-9000
Recorders: Sound Devices MixPre-6, iRiver iHP-120 (Rockboxed & RTC mod)

Recordings on the LMA: http://www.archive.org/bookmarks/ChuckM
Recording website & blog: http://www.timebetweenthenotes.com

Offline voltronic

  • Trade Count: (40)
  • Needs to get out more...
  • *****
  • Posts: 4104
I just read this thread. Here is a phone app that may be useful for this application.

https://play.google.com/store/apps/details?id=air.com.neumann.recordingtools

I have used that app, and while it is pretty good for SZ calculations, it doesn't do much else.

Recently I have been using this one instead.  It has been removed from the Play Store for some reason, but is still available elsewhere:
https://apkpure.com/neoduction-tools/com.neoduction.tools
I am hitting my head against the walls, but the walls are giving way.
- Gustav Mahler

Acoustic Recording Techniques
Team Classical
Team Line Audio
Team DPA

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (15)
  • Needs to get out more...
  • *****
  • Posts: 15698
  • Gender: Male
  • "Better to love music than respect it" ~Stravinsky
Not to knock these sorts of apps. But a simple screen shot of the Improved PAS table on one's phone (or old-school scrap of paper in the recording bag with the table printed on it) will be faster, easier and more straight-forward as a reference for applying Improved PAS. 

Since these apps are likely to use the same or similar underlying data sets, they will likely generate similar answers given the correct input.  However, in order to find the appropriate solution they will require input of the variables as follows: select polar pattern, select microphone angle (same as PAS angle), select desired SRA (PAS angle +10 degrees).. to have the app generate the required microphone spacing dimension.  That is assuming these apps can work in this direction from that particular set of variables.  If they require inputting the microphone spacing first to derive the SRA, they will require going back and forth to home in on the spacing number in an iterative way.   That's both clunky and requires one to be aware of the correct procedure, whereas one can find the solution from the table quickly at a glance, and also get a better feel for where the solution falls in the continuum of pattern/angle/spacing combinations in case one needs to modify the setup.

My primary intent with Improved PAS is keeping it super-simple and easy for non technically-minded tapers to use.  These apps are certainly useful, but I suspect they will be more useful for finding Stereo Zoom answers that are not PAS-specific.

musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline voltronic

  • Trade Count: (40)
  • Needs to get out more...
  • *****
  • Posts: 4104
Not to knock these sorts of apps. But a simple screen shot of the Improved PAS table on one's phone (or old-school scrap of paper in the recording bag with the table printed on it) will be faster, easier and more straight-forward as a reference for applying Improved PAS. 

Since these apps are likely to use the same or similar underlying data sets, they will likely generate similar answers given the correct input.  However, in order to find the appropriate solution they will require input of the variables as follows: select polar pattern, select microphone angle (same as PAS angle), select desired SRA (PAS angle +10 degrees).. to have the app generate the required microphone spacing dimension.  That is assuming these apps can work in this direction from that particular set of variables.  If they require inputting the microphone spacing first to derive the SRA, they will require going back and forth to home in on the spacing number in an iterative way.   That's both clunky and requires one to be aware of the correct procedure, whereas one can find the solution from the table quickly at a glance, and also get a better feel for where the solution falls in the continuum of pattern/angle/spacing combinations in case one needs to modify the setup.

My primary intent with Improved PAS is keeping it super-simple and easy for non technically-minded tapers to use.  These apps are certainly useful, but I suspect they will be more useful for finding Stereo Zoom answers that are not PAS-specific.

I'm sure you are correct.  I don't do stack taping; I use these apps for SRA exactly as you say.
I am hitting my head against the walls, but the walls are giving way.
- Gustav Mahler

Acoustic Recording Techniques
Team Classical
Team Line Audio
Team DPA

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (15)
  • Needs to get out more...
  • *****
  • Posts: 15698
  • Gender: Male
  • "Better to love music than respect it" ~Stravinsky
Partly speculation as I've not used the apps, but certainly some of that rings true.

Just trying to clarify and don't mean to be pedantic-
Most folks here use the term "stack taping" to refer to making a recording from directly in front of a PA speaker in close proximity to it, such that the PA is effectively close-coupled to the recording position and dominates entire recording for the most part except for audience reaction between songs.  That arguably has more in common with a straight SBD patch than recording from a central audience position using PAS.

I do recognize that you record non-PA amplified material for the most part, which is what I think you intended to convey.

« Last Edit: January 30, 2019, 10:41:11 AM by Gutbucket »
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline fobstl

  • Trade Count: (4)
  • Taperssection All-Star
  • ****
  • Posts: 1629
My plan was to aim the mics at the stacks, use the Neumann app to show me what angle I just aimed them in, then go to Gutbucket's chart to show me how far apart to space them.

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (15)
  • Needs to get out more...
  • *****
  • Posts: 15698
  • Gender: Male
  • "Better to love music than respect it" ~Stravinsky
That makes good sense and alternate angle-finding apps will also work.  Determining the PAS angle is the fuzziest step in the process when estimating the angle by the fist-viewed-at-arm's-length method.
musical volition > vibrations > voltages > numeric values > voltages > vibrations> virtual teleportation time-machine experience
Better recording made easy - >>Improved PAS table<< | Made excellent- >>click here to download the Oddball Microphone Technique illustrated PDF booklet<< (note: This is a 1st draft, now several years old and in need of revision!  Stay tuned)

Offline dyneq

  • Trade Count: (12)
  • Taperssection Member
  • ***
  • Posts: 821
Agreed on KISS for this particular method being a strength. For those on Android, I've been using this Protractor app:

https://play.google.com/store/apps/details?id=com.keuwl.protractor&hl=en_US

I like this app because you can point your camera at the stage from your stand and hit the 'Pause' button which freezes the image. Then, drag the angle lines to wherever you plan to point each mic on each stack to get your angle. I have a printout of the PAS angle/distance chart and use that to look up the distance between mics for my measured angle.

Offline voltronic

  • Trade Count: (40)
  • Needs to get out more...
  • *****
  • Posts: 4104
Agreed on KISS for this particular method being a strength. For those on Android, I've been using this Protractor app:

https://play.google.com/store/apps/details?id=com.keuwl.protractor&hl=en_US

I like this app because you can point your camera at the stage from your stand and hit the 'Pause' button which freezes the image. Then, drag the angle lines to wherever you plan to point each mic on each stack to get your angle. I have a printout of the PAS angle/distance chart and use that to look up the distance between mics for my measured angle.

I do a similar thing with AP Bearing Compass:
https://play.google.com/store/apps/details?id=com.appyhand.bearingcompass
I am hitting my head against the walls, but the walls are giving way.
- Gustav Mahler

Acoustic Recording Techniques
Team Classical
Team Line Audio
Team DPA

 

RSS | Mobile
Page created in 0.145 seconds with 44 queries.
© 2002-2024 Taperssection.com
Powered by SMF