Topic: Please Help Me Build a Semi-Stealth Rig

[glennjr]

I'm hoping to get your opinions on a semi-stealth rig to build. I'm new to stealth recording and I think I'm not aware of all the options that are out there. so please let me know if I'm headed in the right direction. Any advice is much appreciated.

I'm looking to put together a semi-stealth rig for recording ambiances with people (inside train, restaurant, shopping mall, etc). So it doesn't need to be super small or truly hidden, but rather, not LOOK like a bag full of recording gear - like my DR-680 & Petrol bag looks like now!

I'd like to use my CM3's for this or something similar...maybe even my AT825 or similar one-point type mics. I don't necessarily need to use lavs for this rig. What this guy has going is probably what I'll end up with structurally:

http://thesoundmyheadmakes.blogspot.tw/2011/11/stealth-rig-prototype.html


My biggest concern is having clean preamps. If the recorder has XLR inputs, that would be great, but so far I'm wary of what I'm seeing in the handheld recorder department.

I'm considering to go with the Nagra Lino for the recorder. But not sure the best way to get a stereo signal into it. I've seen a post here saying you can cut a dual RCA to mini-jack cable and solder XLR's to it, but not sure if plugging that directly into the Lino would work. I'd probably need something to supply the phantom power, right?

What else would you recommend in the recorder department? The less 'moving parts' the better. But I'd consider something like the tinybox if need be. I'd like to spend no more than $500...maybe could go to $600.

Thanks for help and wisdom!

[acidjack]

If you are running your DR-680, the pres in it are fine.  I don't think people have many complaints about them.

If you want a smaller recorder for all-in-one, I have been running the Roland R-26 and find the preamps to be good. It also has a very good, clear display, easy level adjustments for the analog inputs, and solid battery life. And it's less than half the size of your 680.  The R-26 has XLR line-ins so you can run the CM3s straight into it.

As to mics, I haven't done the type of recording you are doing, so I may not be the best person to ask, but I would think you want some omnidirectional mics to pick up the full feel of the ambient environments you are in, if I read you correctly.  For that, it is hard to go wrong with something like the Countryman B3 (about $350 and needs to be wired up by someone, runs off plug-in power and doesn't need phantom), Nevaton MCE400 (a bit hard to find) or DPA 4060 (much more expensive, but quite easy to find). 

If your CM3s are omnidirectional, I don't see any reason not to use them. 

It would be helpful to know your budget, and exactly what you're hoping to use the recordings for.

[ScoobieKW]

The Sony M10 retails for around 200-220 USD, has great battery life, is small, and has a quiet input stage. A tinybox with 9v/48v power options would pair with it well. The comibination will come in around your 500-600 range. Alternatively, you can use skip the tinybox, the M10 has good preamps, and use a portable phantom supply like a Denecke PS-2.

As far as going from XLR to 1/8" inputs on small recorders, with most mics you use a passive adapter cable that connects pins 1 and 3 from the xlr with the signal on 2 (ask for a dual balanced XLR cable to 1/8 stereo adapter) The tinybox's active conversion from balanced to unbalanced will work with a wider range of mics, so it will depend on which mics you choose.

[Gutbucket]

A couple thoughts-

For recording spatially enveloping ambiences, I'd choose a near-spaced directional mic setup (like ORTF) or a near-spaced baffled omni setup (like a Jecklin disk), a configuration with some space between the mics instead of a coincident setup like a single point mic.

Use of relatively sensitive mics which will require less input gain should be appropriate for your indicated ambiences and reduce the need for a really clean (and more expensive) preamp stage.  That will help in keeping your signal-chain noise floor low.

If using mics which require phantom power, either the recorder or an outboard device (phantom supply or preamp) will be needed to provide it.  Take a look at the Tascam handheld [edit- I meant Roland R-26, I missed AJ's post mentioning above, I think Tascam makes one too though] with XLR inputs and phantom power capablities, the model number escapes me at the moment.  There are a few other handhelds with 48V phantom power, but not that many.

If building a cage to house the mics similar to that shown in the link you posted above, avoid attaching the recorder and power supply on the outside of the cage directly next to the mics as shown.  That position will interfere with sound pickup, blocking it from the sides, and creating reflections from the front.  Below is the combined stereo polar pickup pattern of two cardioids arranged as an ORTF pair (image from Stan Linkwitz's website, which I used previously in a thread here at TS), as you can see, there is significant pickup from the those angles.  Better to keep the mics unobstructed in the horizontal plane, and attach the other equipment above of below them.

[acidjack]

The Sony M10 retails for around 200-220 USD, has great battery life, is small, and has a quiet input stage. A tinybox with 9v/48v power options would pair with it well. The comibination will come in around your 500-600 range. Alternatively, you can use skip the tinybox, the M10 has good preamps, and use a portable phantom supply like a Denecke PS-2.

As far as going from XLR to 1/8" inputs on small recorders, with most mics you use a passive adapter cable that connects pins 1 and 3 from the xlr with the signal on 2 (ask for a dual balanced XLR cable to 1/8 stereo adapter) The tinybox's active conversion from balanced to unbalanced will work with a wider range of mics, so it will depend on which mics you choose.

I don't agree with this at all. I know it's the CW on this board, everyone owns the M10 (including me), and everyone likes to talk about how great it is.  And it is the best $200 recorder, bar none.  But having used it for quieter recordings, I would not call the inputs "quiet" nor the preamps "good" regardless of what any spec sheet says. Maybe it's a little better than other cheap recorders, but assuming the recording being done is critical (i.e., needs to be free of obvious hiss), I think someone doing nature or ambient recording would need to look elsewhere.  YMMV and all that, just speaking to my own experience.

[F.O.Bean]

I would run ca14 omnis on an ORTF or NOS bar or something like that, and use a ca 9200 preamp into an m10s mic/line input

[glennjr]

Thanks everyone for the quick replies. You guys are awesome!

For the mics, I'm probably going to stick with the CM3's (Cards), and will be ordering a pair of Line Audio's OM1's (omni). I've tried the CM3's in ORTF and felt they sounded pretty nice. I'm still open to other mic options, so I'm happy to hear any suggestions.

If building a cage to house the mics similar to that shown in the link you posted above, avoid attaching the recorder and power supply on the outside of the cage directly next to the mics as shown.  That position will interfere with sound pickup, blocking it from the sides, and creating reflections from the front. 

Thank you for bringing that up. I hadn't thought it through to that point. Definitely above and beyond on that one!

About the pre's....low noise and uncolored for sure. I got the Busman mod for my 680 and they sound great. I was hoping to have something comparable with the smaller rig. I was thinking I would likely have to buy an external pre to get to (or beyond) that level. Then just use the recorder for AD conversion and functionality. Lino seemed to fit that bill. But maybe not. Again, the simpler the better; but maybe I can't get what I want with the pre's on today's current offering of handhelds.

It would be helpful to know your budget, and exactly what you're hoping to use the recordings for.

$600 tops for everything.

The recordings will have no particular use for now. But my hopes are in XX number of years I'll have a decent library of ambiance, foley and general sound fx to offer as a sound effects library. I've been recording the usual suspects in my home studio and more recently out and about with the dr-680, but have been falling short capturing anything where people are involved. Being a white guy in Asia gets enough stares as it is...but when you're carrying a bag with wires, boom and mics to boot, it kind of kills the "natural-ness" of the space. So here I am.

Thanks again

[acidjack]

About the pre's....low noise and uncolored for sure. I got the Busman mod for my 680 and they sound great. I was hoping to have something comparable with the smaller rig. I was thinking I would likely have to buy an external pre to get to (or beyond) that level. Then just use the recorder for AD conversion and functionality. Lino seemed to fit that bill. But maybe not. Again, the simpler the better; but maybe I can't get what I want with the pre's on today's current offering of handhelds.

If you only need two channels, I would look at an Oade Modded PMD661.  Smaller than the 680 by a lot and you can still do all-in-one. This would appear to be what you need, though it is slightly above your  $600 budget.
http://www.oade.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=OBA&Category_Code=PMD661FET  Of course, an M10/tinybox will be about $500-550 depending on options, too.

[Gutbucket]

You might consider wearing the mics some how.  That can actually often get them in a better location than some sort of box on a floor or table unless you need to remove yourself from the location, and your one's works very well as a baffle between omnis.

I would run ca14 omnis on an ORTF or NOS bar or something like that [snip]

Not enough spacing between the mics, omnis on a ORTF or NOS bar could work with a baffle in the middle though.

[Gutbucket]

$600 tops for everything.

The recordings will have no particular use for now. But my hopes are in XX number of years I'll have a decent library of ambiance, foley and general sound fx to offer as a sound effects library.

Here's maybe a far out idea for you.. and is what I would do, but I'm biased to this direction.  Two variants:

1) Use your existing DR680 and buy 4 or 5 miniature omnis with decent sensitivity and self-noise.  Buy phantom power adapters to step the 680's 48V down to PIP for the miniature omnis.  Alternately you could use Plug In Power battery boxes or preamps to power the mics.  You can do all that within your budget.  Attach the omnis to each side of a 3-dimentional baffle like a box or cylinder, with them facing all horizontal directions.  You can put the recorder and battery inside the box.  That arrangement would be no more bulky than the cage with mics you linked to.

I regularly use 4 or 5 miniature omnis that way, powered with Niant PFA adapters (Niant = Jon Stoppable) into the DR-680.

2) Use four of the same miniature omnis with decent sensitivity and self-noise as above. Buy a Tascam DR2d (recent recurring deals has is new for ~$100), which can record 4 channels as two stereo pairs simultaneously, but provides no phantom power. Power the miniature omnis with two battery boxes or small preamps. I use Church Audio CA-UGLY preamps (build by another small vendor who is a member here) which are very small and provide gain.  The entire rig will fit in a small shaving kit or in pants pockets.  I do this with DPA omnis, which are outside your price range, but you could do all this with less costly mics.  Jon may build a suitable low cost diffuse field type omni which would allow you to buy the recorder, mic preamps and mics, all within budget.   

Then record your ambient sounds and spaces in 4 or 5 channel surround.  You can always discard the extra channels and have two channel stereo, but the material you mention will really benefit from surround playback immersion and having it in 4 or 5 channel format will give you more options for doing interesting things with it, even if you can't listen to it that way now.  I record music that way so I obviously think it’s a valuable and highly rewarding way to record, yet I’m sort of the odd man out around here on that account.  Yet for what you are doing, recording in surround is an even more well suited match.  Consider it.

I wish I had such a setup when I was in Asia.

[glennjr]

Thanks everyone for your further responses. I'm a bit at odds at how to tackle this. And to make things "worse" Gutbucket's suggestion of recording in surround has never crossed my mind. I don't know how much demand there is for properly recorded surround material, but it has piqued my interest! I'm going to research this further. I'll be sure to point my wife to this thread when several new mics show up from the fedex guy. She'll need someone to yell at after I've locked myself in a room. 

I'm still open for more suggestions until I've figured out what I'm going to do.

My next question would be:  Which mini-mics can you recommend that have a near table flat response at a max of $200 each? I couldn't find a freq response chart on Church Audio's mics; would I be lucky enough for them to be pretty flat? Maybe at that price point I'm asking too much. But gotta ask!

thanks!

[Church-Audio]

Thanks everyone for your further responses. I'm a bit at odds at how to tackle this. And to make things "worse" Gutbucket's suggestion of recording in surround has never crossed my mind. I don't know how much demand there is for properly recorded surround material, but it has piqued my interest! I'm going to research this further. I'll be sure to point my wife to this thread when several new mics show up from the fedex guy. She'll need someone to yell at after I've locked myself in a room. 

I'm still open for more suggestions until I've figured out what I'm going to do.

My next question would be:  Which mini-mics can you recommend that have a near table flat response at a max of $200 each? I couldn't find a freq response chart on Church Audio's mics; would I be lucky enough for them to be pretty flat? Maybe at that price point I'm asking too much. But gotta ask!

thanks!

CA-14 CARDS + - 10 dB from 40hz to 20khz.
CA-14 OMNI +- 4 dB 20hz to 20khz
Accuracy of my measurements + - 20%

Don't ever go by frequency response alone with any manufacture unless its DPA because every single one of them is not 100% correct. Frequency response of microphones is a guessing game at best for most manufactures. Its very hard to measure microphone frequency response accurately. Especially in the free field. Its extremely easy to measure the response of a speaker by comparison.

We all do our best to make things accurate in the end its only as good as the source we are using. And placement of the mic in the field of that source. And most company's fudge the plots anyway using smoothing. So go by sound not specs when choosing a mic.

Google Church Audio ca-14 and listen to samples on the interweb.

[F.O.Bean]

Youre a beginner, stick with the 2 channel stuff for now. Surround is very difficult and could turn you off of taping real quick.........Invest in Church Audio CA14 mics and either a Church Audio Battery Box or CA Preamp And get a Sony M10, and you will thank us later

[rjp]

Another worthwhile choice for omni mics would be the Naiant X-X. You can get them phantom powered (9-52V) with XLR connectors, or terminated in other ways such as a miniplug, suitable for plug-in power. Mine have the XLR plugs for phantom power; the other options weren't yet available when I ordered them, and I actually prefer the XLRs for my own purposes.

I've run X-X (clipped to eyeglasses) > Littlebox > Olympus LS-10 with wonderful results.

[glennjr]

Youre a beginner, stick with the 2 channel stuff for now. Surround is very difficult and could turn you off of taping real quick.........Invest in Church Audio CA14 mics and either a Church Audio Battery Box or CA Preamp And get a Sony M10, and you will thank us later

Thanks for the suggestion. I do like to get in over my head with things; then wonder why my life is so difficult!

At my budget I'm certainly not about to ask for Shoeps or DPA quality, but I'm curious how Church Audio and Naiant mics compare? (not based on overall value: cost vs quality, but based solely on quality) If properly placed, will they hold up to a professional's expectations, say a post production engineer looking for ambience for a movie? It's not something 10 years later I would listen back to and say, damn I need to go back and re-record that park with my Shoeps, is it?

There seems to be a good amount of love for these two mic companies here--which does say a lot about their quality--so I hope I didn't offend by asking. I just wouldn't feel right if I didn't follow due diligence. Hence, gotta ask.

From what I'm reading here I think I know the answer. But if need be, I could always save up the extra if it's worth it. (Sure wish I would have done that with my turntable purchases back in my DJ days. Wasted too much money on inferior turntables when I should have just bought the industry standard right off the bat)

Thanks!