Taperssection.com
Gear / Technical Help => Microphones & Setup => Topic started by: cybergaloot on February 07, 2011, 09:36:24 AM
-
http://www.harlanhogan.com/portaboothArticle.shtml
I've wondered about using something like this to isolate mics from reflections if you are against a hard surface like a wall. Thoughts?
-
worth experimenting with but you'll probably find that it leads to a very muddy result.
i suspect it'll just have the effect of filtering out the top end reflections.
Depending on the space and the kind of reverb / reflection you have, it *will* very probably sound less reflective but on closer listening you'll find the muddy low-mid reflections are more obvious. a less desirable result over-all?
However, this may not apply if the sound source is close to the mic. eg spoken dialog
-
I think it might work for emphasising the direct sound, but I see the main problem being the akward size & shape. How often could you actually use it? If you are far back in a room, the sound reaching the mics even from the forward direction is mostly dominated by diffuse reflections and using this may not make a big difference. It could make a significant difference from a closer position that is otherwise too reverberant, but then you'd be blocking sight-lines with a giant box which ain't gonna fly.
As proof of concept, below is a HRTF binaural head with baffles to reduce reflections from everywere outside of a 120 degree forward recording angle (side wall, back wall, and ceiling reflections). It's part of an advanced four or eight channel HRTF system with additional mics behind/above the baffles to capture those reflections. The developer claims it can be placed much farther back than traditional stereo mic configs so perhaps the idea has merit.
Note: the photo is upside down, the baffle on the bottom is supposed to block ceiling reflections and the notch on the top is where the stand attaches-
(http://www.ambiophonics.org/images/New%20Ambiophone.jpg)
-
I have no current need for it, I just wondered if it would work in a situation like the photo of how I used to mount my mics at the blues club I record in most. Now I'm running them at stage lip and pulling the soundboard mix plus mixing in feeds from certain channels and even have a hyper-card aimed at the audience to capture the applause, etc. Its a pain to mix on the fly but that came around from me mixing things for their radio broadcast.
-
Nice to have that balance flexibility.
Seems your room setup in the photo is one that might benefit. but i'm speculating.
-
That's a cool and interesting setup you have in that club cybergaloot, but delaying all those sources to line up correctly probably was quite a task!
Installing some soft surfaces behind and above the mics mounted to the wall would serve a similar purpose and is much easier than trying to use a portable vocal booth. You probably get a lot of "boom" from having your mics up in the corner of the ceiling, but you can't beat the convenience of not having to setup a stand for every show.
-
I don't put mics in the location in the picture anymore but I left the mount up in case anyone else might want to use it. When I was using it I had a piece of foam behind it for a while. I can't say it really helped but then I really didn't hear much of a reflection from that wall when I didn't use it. Being that it is rough wood probably helped but I was worried about that hard metal sign you can see in the picture.
-
Here is a case where it may be better to work with the wall rather than against it. A couple of boundary layer mics mounted on the wall will effectively eliminate the wall as a source of reflections.
I think that portable vocal booth will probably only work as intended for sound sources close to the mic.
-
I was just looking for responses since I had thought about rigging one up in the past and stumbled across a ad for this one. I have no current need.
I do want to look into boundry mics. Where I record most often is a small club with a small stage. They use milk crates to support the monitors just off the stage and I usually put my mics on short stands between two monitors in a wide split omni setup. It sounds fine but the dancers are a problem because they make their funky moves awfully close to the mics sometimes. And the drunks are a problem as well. I was mixing for the radio broadcast last weekend and had my headphones on when I heard something like "ARWURARRUG" and when I looked over a drunk was bent over trying to speak into one of my mics. I jumped up and got over to him and pulled him away explaining that wasn't cool. Anyway, I wondered about maybe putting boundry mics on the ceiling (relatively low, 10' tops) and just leaving them there. I've thought about using chorus mics too. But I am in love with my ADK-tl's and would hate to loose the detail those mics can bring out.
-
Count me as a fan of both boundary mounting and the TLs. :)
-
What is a good but economical boundary mic? Do they come in matched pairs at all?
-
Something like that might make a difference. Perhaps not a good difference. But if you're near an A/C vent or other distraction it could help to make a mic a little more directional. Perhaps putting a knitted sweater over the box, or lining the outside with carpet scraps would make it better. But outside of dampening the noise from say a laptop fan that might be right next to said box, not very practical. IMO.
I've got an sE reflexion filter myself. Not that I've used it on location yet. It's just too impractical, not to mention heavy, and really not big enough to use for anything more than blocking out part of the over bearing freeway noise to your rear. If you've got some sort of platform to set it all up on great. Otherwise little more than an accident waiting to happen. As I continue to toy with DIY shock mounts and treatments myself. You really have to just use it and put it through the ringers to decide if it's of use. It could help stealth your mics if they're on stage and pointed away from the audience.
For all of my efforts, the more rigid materials seem to have most noticeable affect. Like carpet. The reflexion filter is actually some sort of wool blend type thing. and two layers, the stuff in the arc is fairly well hidden, but it's about as significant as the panels near the mic. Not to imply significant since it doesn't really protect from floors and ceilings and other stronger influences. But it does help a little... very little. The most effective use I've found for the sE reflexion filter, is if I'm talking into a headset mic, I can literally burry my head into the arch and the combination of it and my body seems to be the most difference IMO. Otherwise on cheap speakers in a noisy room you probably couldn't tell when it was in use or not. Without looking at the waveform or analyzing the frequency spectrum. Yeah it does something, but you're still not going to be able to host a party in the next room without affecting the captured results. To an almost equal degree IMO.
-
I seem to remember reading about a technique where you mount split omnis against a wall or flat surface? Anyone know about that? Is it just a matter of getting the mic(s) close enough to the wall that reflections are a non-issue? (distance shorter than the shortest wavelength in the audible spectrum, maybe?)
-
I seem to remember reading about a technique where you mount split omnis against a wall or flat surface? Anyone know about that? Is it just a matter of getting the mic(s) close enough to the wall that reflections are a non-issue? (distance shorter than the shortest wavelength in the audible spectrum, maybe?)
I've seen picture of small diaphragm mics actually taped to a wall. I can remember where or why though.
-
small omnis mounted against a hard surface = boundary mounted. Usually they are A-B spaced since they are omnis.. but they can also be closely mounted on opposing sides of a flat or wedge shaped surface.. or baffled with a sound aborbant surface like a Jecklin disk. Jecklin disk- I think that is the way to think about how things like the isolation box above would work in these kind of scenarios. I've set up baffles between and behind omnis to reduce the sound from the opposite side (J-disk like) or from the room behind. It can work well and that's what I base my speculation on about the box.
I boundary moount small omnis by gaff taping them onto the back wall, the balcony face, the inner stage lip, or directly onto the stage surface (as long as they are safe from being stepped on). I have a couple hard rubber boundary mounts for the DPA 4060s that protect the mics from being crushed, but those are only really necessary for the protection they offer. DPA also makes a dedicated boundary mounted version of the 4060 in a permanent, weighted mount. Any small omni can be used the same way. The boundary mounting technique increases the mic's sensitivity and the ratio of direct sound over indirect sound, so it can work suprisingly well on the back wall even in situations where omnis would otherwise seem too far away. The pickup pattern becomes hemispherical instead of omnidirectional, but it's that direct to indirect ratio business that 'works the magic' in reducing the room reverb and increasing the direct clarity.
I also have a single directional AT boundarymount mic in a steel casing that could probably survive a hard stomping, though I don't use it much since it is only a single mic. AT makes a bunch of different boundary mount type mics, both omni and directional- probably reasonably priced. The directional ones are like half a cardioid pattern. Crown is the originator with the PZM. There are other companies make versions too. But if you have a small pair of Church, Countryman, Core, MM, SP or other small omnis, give it a try sometime.
-
I have a pair of Church's CAFS mics. Maybe I'll try taping them to the ceiling one night and see how they work out.