Become a Site Supporter and Never see Ads again!

Author Topic: Improved PAS setups - better imaging with higher direct-sound/reverberant ratio  (Read 9231 times)

0 Members and 1 Guest are viewing this topic.

Offline MIQ

  • Trade Count: (0)
  • Taperssection Regular
  • **
  • Posts: 194
  • Gender: Male
    • Stereo Mic Tools
Cardioid
Supercardioid
Hypercard patterns

Offline MIQ

  • Trade Count: (0)
  • Taperssection Regular
  • **
  • Posts: 194
  • Gender: Male
    • Stereo Mic Tools
80 deg angle
28cm spacing w each pattern
You lose about 5 degrees off each side if the Recording Angle going from Card to Super to Hyper

Offline MIQ

  • Trade Count: (0)
  • Taperssection Regular
  • **
  • Posts: 194
  • Gender: Male
    • Stereo Mic Tools
90 degrees
20cm spacing
Losing slightly larger amounts off each end of the Recording Angle as you move from Card to Super (9 deg)
and Super to Hyper (6 deg)

Offline MIQ

  • Trade Count: (0)
  • Taperssection Regular
  • **
  • Posts: 194
  • Gender: Male
    • Stereo Mic Tools
110 deg
17cm spacing
Losing similar amounts off each end of the Recording Angle as the DIN styles. Card to Super (9 deg) and Super to Hyper (7 deg).

Smaller angles between mics and bigger spacings lead to less difference between the different patterns. The Recording Angle becomes more dependent on time differences (mic spacing) and less on intensity differences (pattern shape) as the mic angle is reduced.

-Miq

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (13)
  • Needs to get out more...
  • *****
  • Posts: 11414
  • Gender: Male
For concert recording as done around here in situations where the taper chooses to use PAS, wide angles of 80 degrees or more are rare.  Angles narrower narrower than that will be far more common.
volition > vibrations > voltages > numeric values | numeric values > voltages > vibrations > virtual teleportation time-machine experience

Offline MIQ

  • Trade Count: (0)
  • Taperssection Regular
  • **
  • Posts: 194
  • Gender: Male
    • Stereo Mic Tools
Sure, the further back in the room you get from the stacks, the less of an angle you'll need between the mics.  Like your table shows and you've discussed, the angle is getting small and the distance between mic is getting big. The Recording Angle becomes dominated by the arrival time difference and not the level differences caused by the mic patterns. 

Here's Card, Super, Hyper for 60deg mic angle and 50cm spacing

Offline MIQ

  • Trade Count: (0)
  • Taperssection Regular
  • **
  • Posts: 194
  • Gender: Male
    • Stereo Mic Tools
Here is 40 deg mic angle with 90cm spacing
Hardly any change in Rec Angle between them now.

Offline MIQ

  • Trade Count: (0)
  • Taperssection Regular
  • **
  • Posts: 194
  • Gender: Male
    • Stereo Mic Tools
How do you feel about the imaging you perceive when using configurations that rely mostly on arrival time differences (small angle with big spacings)?  To me the image created by widely separated mikes is spacious, but the individual positions of the performers is not well defined.  The other thing that keeps me from wanting to use narrow mic angles is that this often means you are too far back in the room. I realize that we don't always get to pick where we record, but if you get stuck too far back in the room, you get beyond the critical distance and there is not enough direct sound. Too much of the room usually just sounds bad to me. Who wants a recording from a bad seat at the show?

I think some of what has made DIN, NOS and ORTF style configs so popular is that they often work well from places in the room that sound good.  If the performers are spaced 80 to 100 degrees in front of you, you have a good chance at being in a spot that has a favorable direct to reverberant mix. Does that change substantially when the direct sound is coming mainly from the stacks? 

Another reason the semi-coincident configurations are popular is that they combine both arrival time and level differences to determine the image location.  This seems to provide a good compromise between a spacious sound and accurate image placement.

There are places where there is just no choice and you have to deal with a narrow recording angle, or a spot where you want to record with more directional mics to get less room and more direct sound, even when you are not beyond the critical distance. Applying the PAS table you provided or the Stereo Zoom concepts in general will give you a better chance at getting a recording you like.

Miq
« Last Edit: August 19, 2014, 04:11:41 AM by MIQ »

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (13)
  • Needs to get out more...
  • *****
  • Posts: 11414
  • Gender: Male
The critical distance for most rooms is much closer than people generally think. Unless setup on stage, pretty much any recording position from out in the audience is going to be further than the critical distance.  That's certainly true at for unamplified music, a PA will have a somewhat different critical distance due to it controlled directionality, which extends the critical distance further into the room.  This improved PAS technique helps makes the best of normal taping positions which are pretty much always farther away than the critical distance.

The common problem with most PAS setups is not enough spacing between microphones, not too much.  That's due primarily to the limited size of commonly available mounting bars and the practical difficulties of spacing the microphones farther apart when doing so is appropriate, which is most of the time when recording from out in the audience due to the microphone PAS angles involved.  It's easy and common to use a standard narrow bar regardless of microphone angle.  Although it may also be less than ideal to use a wide bar with wide microphone angles, that error simply isn't very common or as much of a problem, certainly not in practical terms.

Some sound preferences are generally objective and agreed upon for most listeners, others will always be more personally subjective.  Much of the driving force behind this PAS stuff is objective as determined by listener testing (the Williams curves and those of other researchers), although within that personal subjective preferences appear in subtleties of degree at the margins.  On a personal level, I really dislike imaging which may be sharp if I hold my head perfectly still but is unstable and moves between the speakers when shift around on playback.  I find that trait more common with coincident setups, those that don't use sufficient spacing, and those which are overly monophonic.  That aspect doesn't bother some listeners as long as the imaging is sufficiently sharp.  It ruins the illusion for me.  I prefer a good balance of imaging, spaciousness, envelopment and ambience, with a stable soundstage.  I really like a good spaced omni recording or Decca tree (three omni) recording in a good room.  Personally I find the faults of wide, stable and immersive but fuzzy far less objectionable than flat, unstable, and overly dry, with pin-point sharp imaging.  It's much closer to what I hear and enjoy at a live performance and is more musically satisfying to me.  It’s the far less egregious error to my ear. 

Stereo is all an illusion.  There are always faults, but with the right knowledge at least the recordist can choose their own lesser poison.  These are just tools to help achieve the desired result, rather than a rules dictating what the results should be.
« Last Edit: August 19, 2014, 11:59:57 AM by Gutbucket »
volition > vibrations > voltages > numeric values | numeric values > voltages > vibrations > virtual teleportation time-machine experience

Offline carlbeck

  • Trade Count: (14)
  • Needs to get out more...
  • *****
  • Posts: 2790
  • Gender: Male
My own recent experimentation has brought me in complete agreement with what was said above. For years I had been running the standard coincident & near coincident patterns, almost to a fault actually. Recently with my new microphones since they weren't actives, ie able to use in an active bar I've experimented with the PAS technique. I've been reading & re-reading the stereo zoom paper which makes a little more sense every time I read it before & after recording a show. For me the PAS technique has made better recordings, as a control factor I've still been running my actives on the same stand in Din or DINa which has been my usual configuration for the last decade. On every occasion I've preferred the PAS recording, it may be a matter of new microphones possibly but I try to focus on the imaging aspect, the feel of the room & overall listening pleasure. I've found the imaging to be just as good if not better with PAS, It's more than likely related to the rooms I record in but the point is that it is working for me. I don't find image quality to be less vs DIN which was my original fear plus I've had the added bonus of picking up more direct sound vs room reverb. Again, I think for what I do, recording rock & roll shows usually FOB within 50ft of the stage PAS is a better fit, if I ever run on stage then I will revert back to DIN, DINa or ORTF but I rarely record on stage. As with everything it's a personal preference, if it works for you & you're pleased with your recordings then it's a win-win in my book.
I know you like, tape for people's approval and stuff, and wave your tapes around like they're your dick...  but even you can't actually think section tapes from philips sound good.  



Mics: Telefunken Elam 260, 61, 62, MBHO KA200, KA500 > Niant PFA's, AKG C34L-MS
Preamps: Grace Lunatec V2, Shure FP24
Decks: Tascam DR-2d, Zoom F8

Old rig: Recording: AKG C34 & AKG CK1X or CK2X > MK46 > 460 > Aeta Mix2000 > Sound Devices 702

Playback: Thorens TD125, Denon DVD-2900> Bel Canto DAC-1 > Audible Illusions 3B > Rogue Atlas >ZU Wax Shotgun> Hyperion 938
ALL TUBES BABY!!!

Offline MIQ

  • Trade Count: (0)
  • Taperssection Regular
  • **
  • Posts: 194
  • Gender: Male
    • Stereo Mic Tools
Thanks for the great replies.  :)

The critical distance for most rooms is much closer than people generally think. Unless setup on stage, pretty much any recording position from out in the audience is going to be further than the critical distance.  That's certainly true at for unamplified music, a PA will have a somewhat different critical distance due to it controlled directionality, which extends the critical distance further into the room.  This improved PAS technique helps makes the best of normal taping positions which are pretty much always farther away than the critical distance.

I probably should have written "well beyond the critical distance".

Carlbeck, in your recent experiments do you recall the recording/PAS angles you used?  Were they less than 60 deg? 

I like and think I understand the advantages of capturing as much of the direct PA sound using directional mics pointed on axis at the stacks.  I'm still wondering what the venues are like that have really narrow recording/PAS angles but still have a nice direct to room sound at the mics. The rooms I've taped in aren't huge and have a square or rectangular floor plan with the stage along the long side of the rectangle.  I'm usually able to get fairly close to the stage with my mics. I guess I could imagine and think I have seen a few pics here of narrow rooms that might require narrow mic angles and still have a good balance of direct and room sound.  The times I've had to record more narrow recording angles have been from places in the room that had too much room sound and I have not liked the recordings.

For people applying the PAS technique or the Stereo Zoom techniques in general, what kind of recording/PAS angles are you using?  What are they for the recordings you think sound the best?  What is the range of "normal" recording angles for the kind of taping most people are doing around here? 

Miq

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (13)
  • Needs to get out more...
  • *****
  • Posts: 11414
  • Gender: Male
The times I've had to record more narrow recording angles have been from places in the room that had too much room sound and I have not liked the recordings.

Making the best of those kinds of less than ideal situations is the primary goal of this technique.  That and simplifying setup.

At the critical distance in a good sounding room, a pair of omnis are likely to get a good balance of direct and reverberant sound. From far away, pointing directional mics directly at the source makes the most of the direct sound reaches that position.

When recording closer to the critical distance in good sounding environments, the Stereo Zoom concept on which this technique is based still applies, but it becomes less and less necessary to point highly directional microphones right at the PA to maximize the pickup of whatever direct sound is available reaching the recording position.  So alternate Stereo Zoom solutions may be prefered which provide different flavors of imaging, different perceptions of depth, and different balances of room sound and distribution of that reverberation in the playback image.  At some point when moving closer (remaining on-axis to the PA, not moving into the "too close, off-axis dead zone" of the PA, which is a different issue), the sound will get overly dry using this technique and choosing another setup which doesn't emphasize the direct PA sound maximally will be a better choice.  But that's far less common for most tapers than being in a less than great sounding room and/or recording from farther back.
volition > vibrations > voltages > numeric values | numeric values > voltages > vibrations > virtual teleportation time-machine experience

Offline carlbeck

  • Trade Count: (14)
  • Needs to get out more...
  • *****
  • Posts: 2790
  • Gender: Male
Thanks for the great replies.  :)

The critical distance for most rooms is much closer than people generally think. Unless setup on stage, pretty much any recording position from out in the audience is going to be further than the critical distance.  That's certainly true at for unamplified music, a PA will have a somewhat different critical distance due to it controlled directionality, which extends the critical distance further into the room.  This improved PAS technique helps makes the best of normal taping positions which are pretty much always farther away than the critical distance.

I probably should have written "well beyond the critical distance".

Carlbeck, in your recent experiments do you recall the recording/PAS angles you used?  Were they less than 60 deg? 

For people applying the PAS technique or the Stereo Zoom techniques in general, what kind of recording/PAS angles are you using?  What are they for the recordings you think sound the best?  What is the range of "normal" recording angles for the kind of taping most people are doing around here? 

Miq

I've been between 60 & 70 degrees on average, it's not that different than a standard DIN in most cases but I've been focusing on achieving better distance between the capsules. Quite frankly unless you're an imaging nut like I am most wouldn't tell the difference. The benefit has been easier set up (for me at the time of the show) with a noticeable improvement in direct sound. Last night I taped in a small bar setting & we had the opportunity to clamp on a beam that was two feet from the stacks (speakers actually) so I ran DIN, it made sense being on top of the sound source & less than three feet off the stage. Imaging is of course superb but I attribute that more to the location of soundsource than standard configs.
I know you like, tape for people's approval and stuff, and wave your tapes around like they're your dick...  but even you can't actually think section tapes from philips sound good.  



Mics: Telefunken Elam 260, 61, 62, MBHO KA200, KA500 > Niant PFA's, AKG C34L-MS
Preamps: Grace Lunatec V2, Shure FP24
Decks: Tascam DR-2d, Zoom F8

Old rig: Recording: AKG C34 & AKG CK1X or CK2X > MK46 > 460 > Aeta Mix2000 > Sound Devices 702

Playback: Thorens TD125, Denon DVD-2900> Bel Canto DAC-1 > Audible Illusions 3B > Rogue Atlas >ZU Wax Shotgun> Hyperion 938
ALL TUBES BABY!!!

Offline MIQ

  • Trade Count: (0)
  • Taperssection Regular
  • **
  • Posts: 194
  • Gender: Male
    • Stereo Mic Tools
Gut, nice explanation of the application of different mic techniques to different recording locations, and the transition from wanting to capture as much direct PA sound as possible to applying the Stereo Zoom concepts to optimize for, or flavor with, other recording attributes.
 
Quite frankly unless you're an imaging nut like I am most wouldn't tell the difference.

I'm definitely an imaging nut too.    ;D

Thanks

Offline Gutbucket

  • record > listen > revise technique
  • Trade Count: (13)
  • Needs to get out more...
  • *****
  • Posts: 11414
  • Gender: Male
Try figure 8's in PAS outdoors.  They require the least spacing between mics of any pattern.  See here- http://taperssection.com/index.php?topic=177050.0
volition > vibrations > voltages > numeric values | numeric values > voltages > vibrations > virtual teleportation time-machine experience

 

RSS | Mobile
Page created in 0.223 seconds with 37 queries.
© 2002-2017 Taperssection.com
Powered by SMF
Website Design by Foxtrot Media, Inc., a Baltimore Website Company