Home |
Search |
Today's Posts |
#1
|
|||
|
|||
Decca tree size - related to room size?
Is there anything resembling a formula or basic guidelines for sizing
a Decca tree? I know the proportions (2X from left to right, 1.5X from front to back) as described in the New Stereo Soundbook: but can the overall scale be related to the size of the facility somehow? What guidelines would someone use when designing a tree assembly? Is there a smallest practical size or could I rig up 3 Schoeps mini mics into a palm-sized tree? Seriously, what are the tradeoffs for smaller vs larger and could the size be somehow related to how live/dead the room is, or ??? steve |
#2
|
|||
|
|||
Decca tree size - related to room size?
hollywood_steve wrote:
Is there anything resembling a formula or basic guidelines for sizing a Decca tree? I know the proportions (2X from left to right, 1.5X from front to back) as described in the New Stereo Soundbook: but can the overall scale be related to the size of the facility somehow? Not really. It relates to the size of the stereo image you want, and the directionality of the microphones. The standard proportions are about right for M50s. What guidelines would someone use when designing a tree assembly? Is there a smallest practical size or could I rig up 3 Schoeps mini mics into a palm-sized tree? I don't think you can do Decca miking with something as omnidirectional as the Schoeps. The whole point of the system is that it takes advantage of the top end directionality of a large diaphragm omni. Seriously, what are the tradeoffs for smaller vs larger and could the size be somehow related to how live/dead the room is, or ??? The more you pull them apart and toe them out, the more separation you get and the wider the image there is. If everything is clustered in the center, pull them apart. If there's a hole in the middle, move them together. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#3
|
|||
|
|||
Decca tree size - related to room size?
"Scott Dorsey" wrote in message
... I don't think you can do Decca miking with something as omnidirectional as the Schoeps. The whole point of the system is that it takes advantage of the top end directionality of a large diaphragm omni. I agree with this assessment to a point. I've used B&K 4006s in a decca tree and wasn't thrilled with the result. I've used Schoeps but with the MK21 capsules and had pretty good luck there. I like them as they tend to approximate the response of an M50... While I haven't personally tried it, there are also folks that will drill out balls to put on the outside of the capsule and get good results that way... --Ben -- Benjamin Maas Fifth Circle Audio Los Angeles, CA http://www.fifthcircle.com |
#4
|
|||
|
|||
Decca tree size - related to room size?
Is there anything resembling a formula or basic guidelines for sizing
a Decca tree? I know the proportions (2X from left to right, 1.5X from front to back) as described in the New Stereo Soundbook: but can the overall scale be related to the size of the facility somehow? The Decca tree was designed for orchestras. You can scale it down when working with smaller ensembles. Some of the best imaging I've ever heard on Kronos was a smaller Decca tree arrangement set up for a film scoring date they did at Todd-AO. Direct to room ratio was incredible. I'm sure there's a point where downscaling the tree makes it stop working & the imaging falls apart, & I suspect that point will be determined by the pattern of the mics you use. The standard proportions are about right for M50s. Bobby Fernandez, an ace Hollywood orchestral sound track engineer, told me he's converted from M50s to Sennheiser MKH20s. Says he gets the same overall sound, but with a lot less self-noise. I don't think you can do Decca miking with something as omnidirectional as the Schoeps. The whole point of the system is that it takes advantage of the top end directionality of a large diaphragm omni. It may be a stretch to even use the term "Decca tree" in this context, but I heard a system using Coles 4038s in a tree arrangement for the PBS "Sessions" series. Sounded very good, but was really a bit more like 3 spot mics over the band than a coherent stereo image. Might have worked better if they were pulled in together more, but this is a preset flown overhead arrangement, a sort of one size fits all thing for that show. Scott Fraser |
#5
|
|||
|
|||
Decca tree size - related to room size?
David Satz wrote:
Scott Dorsey wrote: I don't think you can do Decca miking with something as omnidirectional as the Schoeps. The whole point of the system is that it takes advantage of the top end directionality of a large diaphragm omni. The Neumann M 50 and its successors aren't large-diaphragm--they're small- diaphragm pressure microphones with the transducer embedded in the surface of a Lucite sphere. The sphere makes the response above a few kHz more strongly directional, and bumps up the on-axis response slightly. Okay, I'd call the M50 a large diaphragm, in that it's large enough for off-axis response effects to exist, but that's just me. I'd say the same for the 1" B&K as well. But yes, it's true that the sphere is where most of the beaminess comes from. What that description doesn't convey is the greatly increased focusing ability of the microphones at a distance from the sound source. This amazed me when I worked with M 50s at RCA Studios (they were a favorite of our late head producer, Mr. Jack Pfeiffer). I recorded a CD of the Tokyo String Quartet with M 50s under his supervision--the microphones were over twice as far from the quartet as I would ever have placed any pair of normal omnis, yet the sound is highly detailed without being the least bit screechy. Yes, this is true. You can also use the same mikes, incidentally, in a baffled configuration and get a lot of that. To mimic this setup with conventional pressure (omnidirectional) capsules, both Schoeps and Neumann sell accessory spheres that can be slipped over the ends of their respective small microphones. Schoeps even offers two different sizes of sphere, each with a slightly different effect. Details can be seen on http://www.schoeps.de/E/ka40-50.html which also gives a set of frequency response graphs that show that aspect of the spheres' effect. Neumann's Web site shows the polar response graphs of their current models "M 150 Tube" and TLM 50, both of which use this type of construction; see http://www.neumann.com/infopool/mics...?ProdID=tlm50s and click on the tiny word "Diagrams" near the top of the page. B&K also sells them, and I have never been able to get anything even approaching the general sound of the M50 with them. It does increase the high frequency directionality and I like using them that way with baffled miking configurations, but I never could make them (or at least the B&Ks) work in a Decca tree anything like the M50. I've recorded only a little with Schoeps KA 40 spheres on MK 2S capsules. It was a useful and pleasant experience; the effect of the spheres was definitely quite noticeable. I mostly work with directional microphones but if I were to use omnis again, I think that I would use the spheres on them. The ability to back the microphones away from the sound source and still maintain good focus helps to solve one of the real problems of spaced-omni recording, which is the undue extra clarity given to sound sources that are at the front of the ensemble as opposed to those which are located farther back. There should be a difference--but when omnis (or any other pattern of microphone to some extent, but omnis especially) are close to the front edge of the ensemble, the players in back may be literally ten times as far from the microphones as the players in front. Reducing that from 10:1 to, say, 3:1 is a real improvement to my ears. I agree, and I like the spheres a lot in general, but I still can't make them work with a Decca tree and I haven't seen anyone else do it to my satisfaction either. There's a local fellow here who uses MKH-20s with the balls and it just doesn't sound like what I hear in the hall at all. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#6
|
|||
|
|||
Decca tree size - related to room size?
|
Reply |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Question on Room Size | High End Audio |