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Gear / Technical Help => Microphones & Setup => Topic started by: ArchivalAudio on April 17, 2013, 01:44:59 AM
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So I made me a DIY spaced omni bar out of 3' aluminum tube. for my Busman BSC2's [Active caps]
Should work for any active style system.
I made this for myself, and no I won't make any for sale.
Someone could easily follow this pictorial and make their own easily, all parts were purchased at Lowes... except the RODE shock mount and the K&M clamp.
--Ian
Enjoy: ;D
Parts:
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file.jpg.html)
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file.jpg.html)
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-2.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-2.jpg.html)
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-3.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-3.jpg.html)
End with Wedge Bolt inserted:
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-4.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-4.jpg.html)
Shrink tubing on center:
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-5.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-5.jpg.html)
PVC Hot melt glued in place over shrink tube:
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-6.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-6.jpg.html)
Spray paint, first flat back then the (toxic) textured paint:
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-7.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-7.jpg.html)
Final assembled with BSC2's:
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-8.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-8.jpg.html)
Measures = about 41" spread:
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-9.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-9.jpg.html)
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-12.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-12.jpg.html)
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-11.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-11.jpg.html)
41" end with tape measure:
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-10.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-10.jpg.html)
Final all assembled in RODE Shock on stand:
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-13.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-13.jpg.html)
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very nice!! I have a weekend project. Thanks
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Nice work!
If you have the capability to record more than 2 channels and another microphone, give it a try with a single directional mic in the center facing forward. A cardioid or supercard with a rolled off bottom end works well for that. You could simply clamp it to the supporting stand directly under the omni bar and best if your clamp allows you to place that mic about 8" to 20" forward of the omnis.
The setup pulls heat from music with ruthless efficiency like a good-cop/bad-cop interrogation team shaking down a perp. The omnis contribute the spaced omni goodness- openess, naturalness, deep dimensional bottom-end and evelopement. The directional mic brings out the clarity, details, and presence from the direct sound and solidifys the imaging. Since it is pointing directly ahead it maximally excludes ambience and leaves that to the omnis, and instead focuses on the sound arriving from dead ahead. It's a complementary match like sweet & sour, chocolate & peanutbutter, rock & roll.
Pull up the the omnis and pan them hard left/right, adjust balance (and EQ if you do that), then pan the directional mic to center and bring it up until it blends best and brings out the "oh yeah!" in you. Also try going louder than you think the center directional should be and bring it down to what sounds good. Play with it a bit and be amazed.
Avoid the strong temptation to add a typical near-spaced stereo pair in the center unless that's just for comparison. If you feel you simply must use four mics instead of three, run the two in the center as X/Y or M/S.. or point the fourth one directly away from the stage opposite to the center one and gain creative control over front/back depth, audience reaction and ambience.
Achieve mastery over the outdoor ampitheater, Ian, like a taper god.
Or just enjoy running two split omnis. ;)
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Below is a link to a Michael Williams diagram for a cool mic config using 3 cardioids with the same Left-Right mic spacing as your bar. It produces a recording angle of ~110degrees total (typical for the usual setups used around here), and leverages that spaced 3-mic goodness.
It's a Stereo Zoom 5-channel setup, but if you ignore the rear facing mics and mix the 3 forward facing mics to 2 channel stereo, you'll smile widely and feel the sun shining down on you like it was that gorgeous day you made the recording.
http://www.mmad.info/MAD/5Ch/5ch_Surround/Card/All/FTC55/B60/BPC40/Plan%20A.pdf (http://www.mmad.info/MAD/5Ch/5ch_Surround/Card/All/FTC55/B60/BPC40/Plan%20A.pdf)
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Nice work AA! will u please make me one :P ;D JK. I am using the large AB NolaBar and old tv rabbit ears for my ca14 omnis
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How far do you have to be from the stage to use omnis and how far apart should you put them?
I too have CA-14 omnis and wanted to use them but wasn't too sure how to set them up. I can set up on a table 8-10 ft dead center in front of the stage w/ no problems.
Thanks,
SW
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How far do you have to be from the stage to use omnis and how far apart should you put them?
I too have CA-14 omnis and wanted to use them but wasn't too sure how to set them up. I can set up on a table 8-10 ft dead center in front of the stage w/ no problems.
Thanks,
SW
You will want the omnis much higher than a table surface to avoid chatter and make them sound as good as possible. Splitting them more than 1 foot is what most people do
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Nice work!
If you have the capability to record more than 2 channels and another microphone, give it a try with a single directional mic in the center facing forward. A cardioid or supercard with a rolled off bottom end works well for that. You could simply clamp it to the supporting stand directly under the omni bar and best if your clamp allows you to place that mic about 8" to 20" forward of the omnis.
The setup pulls heat from music with ruthless efficiency like a good-cop/bad-cop interrogation team shaking down a perp. The omnis contribute the spaced omni goodness- openess, naturalness, deep dimensional bottom-end and evelopement. The directional mic brings out the clarity, details, and presence from the direct sound and solidifys the imaging. Since it is pointing directly ahead it maximally excludes ambience and leaves that to the omnis, and instead focuses on the sound arriving from dead ahead. It's a complementary match like sweet & sour, chocolate & peanutbutter, rock & roll.
Pull up the the omnis and pan them hard left/right, adjust balance (and EQ if you do that), then pan the directional mic to center and bring it up until it blends best and brings out the "oh yeah!" in you. Also try going louder than you think the center directional should be and bring it down to what sounds good. Play with it a bit and be amazed.
Avoid the strong temptation to add a typical near-spaced stereo pair in the center unless that's just for comparison. If you feel you simply must use four mics instead of three, run the two in the center as X/Y or M/S.. or point the fourth one directly away from the stage opposite to the center one and gain creative control over front/back depth, audience reaction and ambience.
Achieve mastery over the outdoor ampitheater, Ian, like a taper god.
Or just enjoy running two split omnis. ;)
Ahhh sounds very nice, indeed. similar to the nakamichi 3 mic blend, in the 550 or the 350 decks...
I have always thought ( in my mind) that 4 mics in stereo are better than 3, but I may try that set up, since I am trying to get stereo why have one mono and 2 syereo. Why not 2 pairs.
or 3 for that matter...
Ideally I'd mix the omnis and a pair of cards in post.
I do like the way MS can acheive a wide or narrow stereo image, So I liken the one center mic and 2 omnis in a similar fashion.
Yes I have a DR-680
I do resemble this statement:
Achieve mastery over the outdoor amphitheater, Ian, like a taper god.
I can relate....
now to get to an amphitheater.
Thanx for the ideas...
--Ian
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very nice!! I have a weekend project. Thanks
Go for it!
Took me longer than a weekend... but that was from concept to getting parts, then to making then later painting. I also took time to sand and steel wool the bar and PVC.
Had assistance from my heat gun for the shrink tubing, and hot met glue.
Including heating the assembly slightly before coats of paint, and to aid the the evaporative off-gassing process to achieve the quality texture I desired...
please share your results and improvements...
--Ian
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Nice work AA! will u please make me one :P ;D JK. I am using the large AB NolaBar and old tv rabbit ears for my ca14 omnis
Bean... you could make one of these for your schemps easily...
easy ;D ;D ;D
--Ian
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PS I used the RODE shock because I had it and it was wider then the Nady (busman) mounts
(http://www.nadypro.com/prod_images_large/ssm5_clip1.jpg)
or the Joe Meek's (http://cachepe.zzounds.com/media/quality,85/p27378h-fd9778cc1dd48d4462ff40c7c7bc8042.jpg,)
that I own.
The Bar seemed to have less side to side sway with the wider shock mount. with this RODE mount:
(http://www.sweetwater.com/images/items/1800/SM4-xlarge.jpg)
at $49.95 I thinks it's over priced, But I got this a number of years ago and only use occasionally, as I like more lower profile shock mounts.
For this purpose it works very well.
--Ian
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Below is a link to a Michael Williams diagram for a cool mic config using 3 cardioids with the same Left-Right mic spacing as your bar. It produces a recording angle of ~110degrees total (typical for the usual setups used around here), and leverages that spaced 3-mic goodness.
It's a Stereo Zoom 5-channel setup, but if you ignore the rear facing mics and mix the 3 forward facing mics to 2 channel stereo, you'll smile widely and feel the sun shining down on you like it was that gorgeous day you made the recording.
http://www.mmad.info/MAD/5Ch/5ch_Surround/Card/All/FTC55/B60/BPC40/Plan%20A.pdf (http://www.mmad.info/MAD/5Ch/5ch_Surround/Card/All/FTC55/B60/BPC40/Plan%20A.pdf)
Yes Yes Yes!
if you ignore the rear facing mics and mix the 3 forward facing mics to 2 channel stereo, you'll smile widely and feel the sun shining down on you like it was that gorgeous day you made the recording
I am sure this would be very fun to do!
than you
--Ian
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How far do you have to be from the stage to use omnis and how far apart should you put them?
You can put them directly on-stage. I try to stay say 3' or so away from the instrument souces (although last night I had three supercards in an equilateral triangle about 2' from the drums of an organ trio in a small room). I'd suggest spacing omnis at least ~15" apart at a bare minimum unless you have a Jecklin disk or some other form of acoustic baffle between them, in which case they can be closer together. ~2' apart is typically a good safe bet, but 3' or even 4' may be better in some cases.
Outside from farther back ~3' (1m) spaced omnis are typically a safe bet for straight 2 channel. Using three channels that spacing works too, but with the addition of the third mic in the center you can go much wider with the Left/Right omnis without getting typical over-wide problems. For the past year or so for outside festival recording, I've doubled my omni spread on multichannel channel setups to 6' apart and the results are twice as good. :)
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That is very nice man.
I may cop something like this for a lightweight portable omni bar..
It needs to easier to transport than just borrowing Skaggs's, and wider.
Right now I use a slightly beefier homemade 72" aluminum bar (also painted black!) for my regular gig.
I clamp my mics to it though, and your end-mount idea is a great way to shrink footprint.
The telescoping rabbit ears seem a little light for dangling expensive Schoeps caps on..
May also try out the non-phase aligned mid-forward config, see how that sounds compared to what I've been doing lately which is: omnis at 68" or so and centre-mounted XY hypers, all lined up exactly in an attempt at phase cohesion.
Blending those together is definitely better than the sum of its parts - though I'll let Lee decide whether that's because of Gestalt theory, Aristotle, or Bucky Fuller :)
-Cheers!
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Aristotle is out, it's either Gestalt or Bucky!
Ahhh sounds very nice, indeed. similar to the nakamichi 3 mic blend, in the 550 or the 350 decks...
I have always thought ( in my mind) that 4 mics in stereo are better than 3, but I may try that set up, since I am trying to get stereo why have one mono and 2 syereo. Why not 2 pairs.
or 3 for that matter...
Ideally I'd mix the omnis and a pair of cards in post.
I do like the way MS can acheive a wide or narrow stereo image, So I liken the one center mic and 2 omnis in a similar fashion.
Yes I have a DR-680
It took me a few years to fully realize this and work up the guts to really commit to it, but I think one of the most important things I’ve come to understand about multi-mic stereo recording (and by that I don’t mean close-mic’d, mixer panned recording like a typical studio setup or FOH stage-PA, but rather recording using a stereo array of more than 2 microphones) is that there tends to be less value in doing the multiple mic thing if simply adding additional pairs to known good 2-channel stereo configurations.
The problem is that aside from mixing highly separated pairs, such as stage-lip mics + room mics, which is more like mixing AUD + SBD and often works well if done right, most tapers go about experimenting with more than 2 channels by tying to combine stereo pairs which are placed too close together. In short, problems can arise when two pairs of mics optimized for stereo on their own are placed too close to each other and mixed.
Doing it that way is common because it is safe, practical, seems obvious, and others do it- people know their usual 2 channel stereo configurations (ORTF, DIN, Spaced omnis, or whatever) work well and their hope is to improve things by simply adding another pair and mixing them. Unfortunately that doesn’t work well consistently. For it to be more fruitful, one ideally needs to throw out the safety net of the original two channel setups and re-think things as a 3 (or 4 or more) channel setup from the start. Otherwise, with some exceptions, it may be a better bet to simply run the two stereo pairs placed on the same mic-bar or mic-stand as two separate stereo rigs with the idea of simply comparing them against each other. If it works out that mixing those pairs together is an improvement that’s great, but if it doesn’t there is no letdown from unfulfilled expectations.
Good exceptions are the ones I’ve mentioned previously, namely using a single center mic or a coincident X/Y or M/S pair between omnis spaced at least 3’- which works for both the omni pair alone, the coincident pair alone, or both mixed together even though that would probably be better if the omnis could be placed wider. I think that’s because in those cases you have 4 mics but only 3 different mic locations (the coincident center pair counts as a single location) and end up with three different phase relationships between those three points instead of the far more complex phase relationship situation of four different locations with a total of six different phase relationship combinations.
Having 6+ channels available on the 680 opens up lots of options. Sometimes I’ll run a standard stereo pair in addition to a dedicated 3 or 4 channel setup to compare them, just because it makes it easy to do so and keeps me on track with a good reference. And sometimes those intentionally separate recordings made simultaneously into the same recorder mix together nicely, even though that wasn’t really the idea.
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One way which might be helpful in thinking about the "4 mics too close together complexity problem", is to consider the concept underlying the well known 3-to-1 rule, even though that rule is meant for multiple microphone placement when those mic feeds are to be mixed to mono or pan-pot stereo (close mic'd PA or studio recording stuff) and doesn't apply to stereo mic arrays.*
The 3-to-1 rule is usually stated something like this: If two or more microphone sources will be mixed together, the microphones should be at least 3 times as far apart from each other as they are from the source they are supposed to pickup.
The intent of the rule is to minimize phase interactions between more than one mic picking up each source. Non-coincident stereo microphone configurations are parlty based on intentional phase interactions between the micophones. In standard stereo setups those phase interactions are carefully balanced against level differences. That's the basic priciple behind the Stereo Zoom idea. When more mics are introduced in close proximity, the phase interactions get complicated fast and the potential for problems increases radpidly.
*The 3-to-1 rule is actually physically impossible to apply to to stereo mic arrays.
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Very timely thread. Thanks guys! I'll try making a bar and I've been thinking about the three mic setup too. Some fuzzy fur for dead rats and I'm in business!
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One way which might be helpful in thinking about the "4 mics too close together complexity problem", is to consider the concept underlying the well known 3-to-1 rule, even though that rule is meant for multiple microphone placement when those mic feeds are to be mixed to mono or pan-pot stereo (close mic'd PA or studio recording stuff) and doesn't apply to stereo mic arrays.*
The 3-to-1 rule is usually stated something like this: If two or more microphone sources will be mixed together, the microphones should be at least 3 times as far apart from each other as they are from the source they are supposed to pickup.
The intent of the rule is to minimize phase interactions between more than one mic picking up each source. Non-coincident stereo microphone configurations are parlty based on intentional phase interactions between the micophones. In standard stereo setups those phase interactions are carefully balanced against level differences. That's the basic priciple behind the Stereo Zoom idea. When more mics are introduced in close proximity, the phase interactions get complicated fast and the potential for problems increases radpidly.
*The 3-to-1 rule is actually physically impossible to apply to to stereo mic arrays.
This makes sense. Thank you
I still try to wrap my head around stereo = 2 channels so 4 divided by 2 is 2 or stereo. and 3 divided by 2 is 1.5 not two. but then again 1.5 is more than one whole so if 2 is one whole than 1.5 is more than one whole.
yeah... I think I am getting that. I suppose I am attached to pairs....
But I do see the how 3 is more than 2.
--Ian
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Very timely thread. Thanks guys! I'll try making a bar and I've been thinking about the three mic setup too. Some fuzzy fur for dead rats and I'm in business!
glad to help.
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That is very nice man.
I may cop something like this for a lightweight portable omni bar..
It needs to easier to transport than just borrowing Skaggs's, and wider.
-Cheers!
Thanks - happy to inspire others...
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I was drawing little diagrams yesterday to see how complicated the interactions get as more mics are added. Drew a dot for each mic then counted how many lines were needed to connect them all to each other-
1 mic = no phase relationship
2 mics = 1 phase relationship
3 mics = 3 phase relationships
4 mics = 6 phase relationships
5 mics = 10 phase relationships
6 mics = 15 phase relationships
Complexity doesn't mean it can't work, only that things get complicated and the potential for problems becomes greater.
Didn’t mean to sidetrack your DIY omni bar thread, but you got me rolling.
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I'm a little confused; a question about the third (middle) mic: how do I assign it to be neither left or right, but middle? I use Audacity or Audition in post.
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Depends on the software program used. I've never used Audition and havent used Audacity in many years.
Some use the paradigm of an analog mixing board/desk with channel strips for each inidvidual mono or stereo input. In that case you pan that channel's output (routed to the main 2channel stereo output bus) to center, just like you would on a physical mixer. That's probably the easiest to grasp.
On other editors, you click boxes to select the desired output bus(s) for each channel. In that case if you select both the Left and Right main output buses, you route the identical channel output signal to both of them, which is effectively the same as panning to center in a mixer.
Aparently on other editors, one needs to make a duplicate copy of the channel and assign one copy to the Left channel bus and the other to the Right channel bus. Again, as long as the two channels are otherwise identical except for the output routing, that's the same as panning to center.
I see many people on this board talking about duplicating channels to effectively pan things to the center (like the Mid channel in a Mid/Side pair) but I always wonder why they do it that way. It works but is a rather cludgy work around. Their software must have some way to pan a mono input from left to right. If not they couldn't pan things slignty one way or another without major effort.
Most editors allow you to do things in several different ways. If those programs you mention allow you to use a mixing console interface, that's probably the most straightforward way to go about it.
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Interesting question. In audacity you can break a stereo pair into individual tracks panned left and right and/or make a channel mono in the same drop down. Is a mono channel not panned left or right the same as a center panned channel? I would have assumed so but want to make sure I'm not misconstruing it.
I've gotten mono board feeds before and thought about duplicating and then panning each to make it reinforce the mic image a bit but haven't tried it so don't know what the result would be like.
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Interesting question. In audacity you can break a stereo pair into individual tracks panned left and right and/or make a channel mono in the same drop down. Is a mono channel not panned left or right the same as a center panned channel? I would have assumed so but want to make sure I'm not misconstruing it.
We need an Audacity user to answer that.
I've gotten mono board feeds before and thought about duplicating and then panning each to make it reinforce the mic image a bit but haven't tried it so don't know what the result would be like.
Duplicating a single mono channel to two seperate mono channels and then panning those to any position is equivalent to a single mono channel panned center as long as the levels of each are the same and the pan positions are symetrical regardless of their position. If the pan positions aren't symetrical (or if the levels are different), that will pan the mono image over towards one side or the other from center.
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actually happen to be an Audacity user, I just wanted to be sure I understood what center panning equated to. Playing a little with Audacity right now and I say the answer is YES.
Ok, yes, it seems obvious now but two mono channels panned to opposite directions is indeed identical to the single mono channel not panned.
I'm a little confused; a question about the third (middle) mic: how do I assign it to be neither left or right, but middle? I use Audacity or Audition in post.
So in Audacity, choose "mono" in the drop down where you can name the track and make sure to keep the panning in the center. You have a stereo track for the omnis and a single mono track for the middle. My R-44 is usually set to record a stereo pair so in Audacity I choose "split stereo track to mono" in the same drop down and then delete the empty track.
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actually happen to be an Audacity user, I just wanted to be sure I understood what center panning equated to. Playing a little with Audacity right now and I say the answer is YES.
Ok, yes, it seems obvious now but two mono channels panned to opposite directions is indeed identical to the single mono channel not panned.
I'm a little confused; a question about the third (middle) mic: how do I assign it to be neither left or right, but middle? I use Audacity or Audition in post.
So in Audacity, choose "mono" in the drop down where you can name the track and make sure to keep the panning in the center. You have a stereo track for the omnis and a single mono track for the middle. My R-44 is usually set to record a stereo pair so in Audacity I choose "split stereo track to mono" in the same drop down and then delete the empty track.
Thanks a bunch!!! That clears it all up for me. Now, it's off to my shop to fabricate an omni bar...
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How did you insert the wedge bolt into the bar?
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How did you insert the wedge bolt into the bar?
easy... they are made to do this.
one end of the ~ hollow tube ~ (not bar) was a bit dinged up so I used a dremel to widen the end - or flange it open slightly.
see tube label in photo: Abbreviated on the label : ALUM - TUBE (RND)
(http://i272.photobucket.com/albums/jj172/ArchivalAudio/DIY%20Spaced%20Omni%20Bar%202013/file-2.jpg) (http://s272.photobucket.com/user/ArchivalAudio/media/DIY%20Spaced%20Omni%20Bar%202013/file-2.jpg.html)
Then I placed both wedge bolts in as best as I could push them in by hand.
Placed one end on concrete and used a dead blow hammer to hammer one end then the other until they were snugly in place. I tried to rotate the bar to each end, similar to tightening lug nuts on a wheel ~ not too much of one or the other.
Then by the way they are designed I placed the washer and 3/8" nut on the bolt and tightened with a wrench. I used a channel lock "pliers" in the center of the tube where the shrink tubing would go.
I didn't really care if it was roughed up there.
The action of tightening the nut spreads the "wedge" on the bolt.
if you get a set of these and read the instructions it likely would make sense.
Hope that helps
--Ian
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I was drawing little diagrams yesterday to see how complicated the interactions get as more mics are added. Drew a dot for each mic then counted how many lines were needed to connect them all to each other-
1 mic = no phase relationship
2 mics = 1 phase relationship
3 mics = 3 phase relationships
4 mics = 6 phase relationships
5 mics = 10 phase relationships
6 mics = 15 phase relationships
Complexity doesn't mean it can't work, only that things get complicated and the potential for problems becomes greater.
Didn’t mean to sidetrack your DIY omni bar thread, but you got me rolling.
This all does make sense and applies here.
Not really a diversion but applicable.
thanx again
--Ian
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Well done, Ian! Between you, Gutbucket and the suggestions of others in this thread, I'm getting some tantalizing ideas for the outdoor concerts this summer.
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I'm curious about the angle you have your mics at; playing around with the "Visualization of stereo microphone system" at http://www.sengpielaudio.com/Visualization-AB60-E.htm
It seems like you'd have the about the same stereo effect with the omnis at 0° as you would at 90° or 110°.
Does it really matter?
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Even omnidirectonal mics get somewhat directional at high frequencies. The extent to which that happens, and the shape of that pattern is determined by the design of the microphone. Generally the smaller the mic is, the higher in frequency it will retain it's omnidirectionality. It's enough to hear a difference with many omnis.
In general its a good idea to point the mics at the source if you want to get those highest frequencies on your recording. Sometimes people point them straight up for measurement purposes so the respose is uniform from all horizontal directions, or to pick up less of the highest frequencies from the source if that's what they want.
The virtual microphone configuration programs usually model an ideal omni, which doesn't take that aspect into account. It would be difficult to display the relavant data anyway if they did, since it varies by model and doesn't make a difference for most of the audible frequency range.
So in terms of Stereo Recording Angle it doesn't really matter how you point the omnis, only how much you space them. How you point them is more of a timbre / high-frequency response thing.
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Even omnidirectonal mics get somewhat directional at high frequencies. The extent to which that happens, and the shape of that pattern is determined by the design of the microphone. Generally the smaller the mic is, the higher in frequency it will retain it's omnidirectionality. It's enough to hear a difference with many omnis.
In general its a good idea to point the mics at the source if you want to get those highest frequencies on your recording. Sometimes people point them straight up for measurement purposes so the respose is uniform from all horizontal directions, or to pick up less of the highest frequencies from the source if that's what they want.
The virtual microphone configuration programs usually model an ideal omni, which doesn't take that aspect into account. It would be difficult to display the relavant data anyway if they did, since it varies by model and doesn't make a difference for most of the audible frequency range.
So in terms of Stereo Recording Angle it doesn't really matter how you point the omnis, only how much you space them. How you point them is more of a timbre / high-frequency response thing.
That helps a lot, thanks. I built an omni bar using an aluminum bar, not a pipe, and drilled holes in the ends to clip my mics into (painted the obligatory black, of course); so, I can only have my mics at 0° with it like it is. Of course, I could go up like you mentioned.
Simple, but it will do for now.
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Ian, thanks for the inspiration to do this. I like doing this kinda stuff. Now I just need to go to some shows.....
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That's the standard A-B spaced setup- mics parallel, pointing straight ahead. You would probably only want to point them upwards if you are using omnis which have an accentuated high-frequency response and have them positioned rather close to the source, where they might sound overly bright if on-axis.
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Thanks for all the omni info. Just got a DR-680 and finally can do a comparison tonight (AKG ck32 3' split and ck61 PAS), and then I want to try the 3 mic (2 omnis and 1 cardioid) configuration.
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Thanks for all the omni info. Just got a DR-680 and finally can do a comparison tonight (AKG ck32 3' split and ck61 PAS), and then I want to try the 3 mic (2 omnis and 1 cardioid) configuration.
I think we need to have a bastardized name for this, like DINa. I nominate "DTCC" (Decca Tree with Center Cardioid). :P
Seriously, though, I'm gonna try it out this summer--thanks Gut.
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Here's my GAKbar with a Busman CK-1 center...
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Here's my GAKbar with a Busman CK-1 center...
Shields up! All stop. Open a hailing channel.
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:lol:
Tribbles.must.die.
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I like this idea so much I bought the parts to make one today.
I've had good luck with 24 - 28" spacing with my Audix Micro series omnis. So, I'm going to make mine shorter.
I'm wondering if I can grind down the bumps on the Wedge Anchors so the aluminum rod doesn't get so dis-formed when tighting the nut after it's inserted into the tube.
Do you keep the nuts on the ends after you tighten it? I might even pour some epoxy into the tube before inserting the anchor, just to make sure it won't come out again.
Thanks for posting this project. I can make good use of a lightweight spaced omni bar.
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I have materials laying around that would allow building a bar that has approx, half the spacing (about 20 inches). Is this width not adequate to do spaced omins with? I could build it with zero outlay, but am I wasting my time? Is there any advantage to trying spaced omnis at this distance? TIA
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I've made nice recordings with the 24" spacing using Audix Micro omnis.
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I made mine out of a 30" solid aluminum bar with holes drilled in the ends. I clip my omnis in the end. I used a piece of PVC that I epoxied in the center, and have that in a shock mount. I haven't used it yet for music.