Re: Microphone for recording a round table discussion
 

I work mainly in theatres, and without any doubt at all, the most common mic for picking up the actors on stage is the boundary type, usually PCC rather than PZM. For conferences I have a kit of table mount condensers - 12, on vibration reducing mounts. So each person, or perhaps a side by side pair of people have their own, and then the sound op is kept busy identifying who is speaking and reducing the level of all the others - never to zero to cover interruptions, but low enough to stop the nasty comb filtering effects that creep in with multiple mics close together. Where groups sit around the table - either circular, oval or rectangular or square, boundaries work again - and on long tables, one omni boundary per four people facing each other works, adding another for each extra 4 people. Boundaries are less prone to comb filtering, but it still can happen. With a recording, you can sort this in post - so not really an issue. For group work - with minimal kit, you can't beat them.

Re: Microphone for recording a round table discussion
 

One thing to keep in mind with a boundary mic would be to avoid papers and typing if at all possible. Any sound right on the table will be loud.

We have a Bartlett stage mic for an annual young kid drama camp. The first year we used it, there was a western theme. They put straw all over the stage. Crunch, crunch, crunch. The director didn't think much of our mic choice. This summer, the concrete stage was clear, and people were very happy with the results. (I didn't hear the performance either time, so the results are hearsay.) The other improvement was that the loudspeakers were allowed to be in a better position this year, so we could use more gain.

Fortunately, you don't have a PA system and feedback to worry about. You can turn the thing up until it clips. (FWIW, the Bartlett mics have very low noise.) But you do have to worry about papers, typing, finger tappers, etc. But whatever method you use, you can bet a panel member will figure out a way to mess it up.

"Hi. I'm Chris. And I'm mumbling quietly into my hands while crunching on potato chips with my accent from the old country. I've now turned my back to the mic to walk far away from it where I will read an important and very long poem while performing a brisk physical activity with the cellophane potato chip bag. Also, sorry, I have this really bad cold. Sniff. Cough. Crunch..."

Re: Microphone for recording a round table discussion
 

Ya know, a few of us have mentioned separately-tracked lavs, and of course that's an impractical amount of complexity. But here we are advocating using two boundary mics, which are more or less one mic for a group of four people. (Of course each mic will pick up all eight people, just at different levels.)

In reality, it would not be any worse to combine four lavs into one channel, and four more lavs into a second channel. Each channel would have four people {fairly close} and four other people {fairly distant and inaudible}. The final "four into one" mix would certainly be no worse than a boundary mic. And you'd end up with closer micing, a lot less tabletop noise, and less noise from mechanicals in the room.

You could probably get acceptable results from relatively inexpensive lavs ... some specific models have been recommended in other threads in this forum. Of course you'd end up with everyone plugged in and tethered, with wires to get tangled. I'll bet the audio would be as good or better compared to boundary mics ... even if it's a fairly unconventional setup.

Oh, wait ... did someone rule out lavs back at the beginning of this exercise? We still don't know the intended final use for this recording, either.

Re: Microphone for recording a round table discussion
 

Re my post above:

Before someone mentions phasing issues between the lav mics, the setup I described should not violate the "three to one" rule. When a given person is speaking, his mic would be about 8" from his mouth. The mic on the person seated next to him would be at least 24" from the speaker's mouth.

You could improve on this if you distributed the mics on alternate channels. Then, when a given person is speaking, the mics nearest to him would be on the opposite channel, so they'd be potted down in the final mix. The nearest mic on the same channel would be at least 48" away from the speaker's mouth. That should make phasing issues non-existent.

I think the audio would be a little better than with boundary mics, because any given speaker would be picked up by a mic about 8" from his mouth, rather than at arm's length. Still, the complexity, and the tangle of visible wires in the shot, probably do not make this a better overall solution.

Meanwhile, I think Kathy's shoot was last night, so I'm eagerly awaiting her report on the results.

Re: Microphone for recording a round table discussion
 

Thank you everyone for your help. The shoot happened on Friday and I was just able to look/listen to the recording this morning. It seems that the mics picked up everyone OK, everyone is intelligible but as everyone knew the acoustics of the room were horrible. The client was aware of all of this so no surprises there and they were OK with it. I put the mics on the rubber mousepads but they still picked up noises such as rustling paper etc.
They have asked me what could improve the acoustics in the room without destroying the look of the place. I suggested filling the bookcase with books, getting a big rug and what else can I suggest? The windows can't be covered and anything "ugly" that I add would have to stay out cameras sight. Would renting acoustical panels and placing them on the side where the camera is bring any significant improvement? The windows do not have vertical blinds. They have a mesh curtain which has very big holes in it, about 0.5inch squares.
What can I suggest?

Re: Microphone for recording a round table discussion
 

It's a tough nut to crack. They want a room that looks stark and harsh ... it is going to sound stark and harsh. I'm glad they are at least aware of the problem and willing to contemplate some improvements.

You have to think in terms of surface area. Treating just one of the short walls, which is a very small percentage of the room's total surface area, will have a minimal impact on the room's acoustics.

Given that they aren't willing to change the long glass wall, I think the other long wall is the first candidate for change. There are various acoustical treatments that could be used. Certainly acoustical panels could be hung on the wall. Because of the amount of glass I'd suggest covering that long wall as completely as possible ... end to end, floor to ceiling. This could be done with something that is somewhat removable, like OC 703 panels. Or it could be a complete architectural refurbishing, by installing something like one of the Tectum products. Or it could be covering the wall with sound-absorbing ceiling tiles (properly spaced from the wall, with proper absorption behind them) but those are not as maintenance-free as a proper wall covering.

The next biggest area is the ceiling. It could also be covered with absorbing tiles with proper spacing and absorption, or with a Tectum product.

Of course either of the above will make some change in the room appearance, but some of the choices would at least keep the look of "a big white expanse."

Carpeting would help, but of course would not look like that beautiful wood floor. They may be very resistant to changing that. (I would be, if it were my floor!) Remember, surface area is key. Adding a 9' x 12' rug on that huge floor will make only a very small difference. If they keep the wood, that just makes it all that much more important to address the ceiling.

Treating one or both of the short walls would help somewhat, but again, they probably won't want to change the wood. They could install treatment on the wall between the bookshelves. That could be something like 1" thick 703 panels, manufactured to fit. It would not be immediately obvious, unless you looked closely. If the shelves are deep enough, there would still be ample room for books. (But they need to treat more than just this one wall!)

There is a lot of existing data for these various building materials, and a lot of formulas to help calculate reverberation time, etc. For that level of complexity you want to talk with an acoustician.

Of course any change is likely to involve building codes, fire and smoke ratings, etc. By all means make "recommendations" but don't put yourself in the position of giving them "specifications" because if you inadvertently violate some local building code that could come back to haunt you in a very big legal way. Before they make any permanent changes to the room they really should consult someone familiar with the regulatory aspects.

Re: Microphone for recording a round table discussion
 

Thanks Greg. I know the glass wall is one of the biggest issues here. I'm pretty sure they just want to add/change decoration that would help with acoustics and not change any walls etc. This is a historical building and they will not alter it's original design.

Re: Microphone for recording a round table discussion
 

There are a number of curtain and blind styles that would be quite sheer and translucent, to preserve the view but would cut down on acoustic reflections off the windows.

And/or, they could consider some wall-hangings on the opposite wall. Even some pure-white quilts would maintain the stark ultra-modern look, but soak up a lot of acoustic ambient reflections.

Re: Microphone for recording a round table discussion
 

I can suggest acoustic sheer curtains but as for the opposite wall, hanging pure white quilts would be an issue because they project on that wall. They will not install projection screen.

Re: Microphone for recording a round table discussion
 

I'm a little puzzled here. They asked you for suggestions to improve the sound, but they are essentially unwilling to make any changes? Where would they put the "decorations" you mention, except on or in front of the walls? Certainly hanging two or three paintings (where, if not on the walls?) would not make a gnats bit of difference.

You've got three pairs of parallel reflective surfaces: a pair of long walls, a pair of short walls, and the floor/ceiling pair. You need to put absorption on at least one surface of a given pair. Again, since the long walls are the most surface area, that's the logical place to start.

Or you might try a triple-diffusion vacuum pump. If you suck all the air out of the room, the acoustical problems would disappear.

Re: Microphone for recording a round table discussion
 

Richard, could you please be a little more specific about these curtains. I'd like to educate myself a little bit on these specific materials. I'm a bit confused by your description. I thought "translucent" meant something like waxed paper, which lets light through but does not allow you to see objects on the other side ... to my way of thinking that would not preserve the view of the outside. Perhaps if you could refer me to some specific products I could understand what you're talking about. ... Thanks.

Re: Microphone for recording a round table discussion
 

I'm meeting with them shortly to find out what the heck they want.

Re: Microphone for recording a round table discussion
 

There are some acoustical materials that would still look like a stark white wall ... but perhaps with a slightly different texture. They would probably be adequate as a visual projection surface. They could still end up with a stark white ceiling (a few inches lower than the present height), again with a slightly different texture. It's a question of what "appearance" they are trying to retain, and what they are willing to change, in order to gain intelligibility.

Sorry I'm no longer in New York. I would love to attend that meeting with you. Good luck!

Re: Microphone for recording a round table discussion
 

She wouldn't get a recording then, sound doesn't travel through a vaccuum! :-)

Re: Microphone for recording a round table discussion
 

Exactly! That's why the problems would disappear!

Re: Microphone for recording a round table discussion
 

The discussion keeps going around room modification and that seems to be very arduous, expensive, and a lot of work. Back in post #43 Greg said:
So, question: Why wouldn’t something like this work? Separate lav mic for each person and run into a mixer/recorder or mixer then into a recorder. Instead of having a person running the mixer, just set it up with the pots adjusted based on a test run ahead of time (asking each person to talk more or less like they would during the meeting and assuming the discussion would be cordial) and hide it under the table.

For the mics, on Amazon there is an Audio-Technica ATR3350 for $29 and there are many other lavalier mics out there. This was the first one I came across.

For recording, and this is where (for me) things really go into unknown territory. If mics like this would work (don’t know if phantom powered mics would be required), there are a couple options: an 8-channel mixer/recorder or, say, a 12-channel mixer where the recorder would be separate. There is a Tascam DP-03SD for $299.99 new/$199.89 used on Amazon. Search for “Korg D8 Digital Audio Multi Track Recorder” and there are several other multi-track recorders listed under “Customers who viewed this item also viewed”. There are ads for various Behringer models such as the 1202fx 12-channel mixer starting in the $110 -$120 range.

Would there be a problem with one person’s lav picking up the neighbor person speaking?

With regard to the room, the book shelves appear to be a room divider and not a wall. Looks to me like the divider doesn’t go all the way across the room and there is an extension of this room on the other side.

Re: Microphone for recording a round table discussion
 

You're right, this conversation has taken a few twists and turns.

Kathy, the OP, originally said she had only two recording channels; she later increased that and was willing to record at least three separate tracks. At one point she said there would be between 6+1 ppl, and 8+1; at another point she said there would be 13. But she clearly did not have enough capability to mic everyone separately.

That led to discussion of the "best of the worst" solutions (kind of like this year's US Presidential election). I think most of us agreed that boundary mics would be better than other "simple" options.

We then digressed into what effect the room acoustics would have on the result. Many of us felt the room would be "very challenging" at best, but Kathy seems to feel her recent recordings were at least usable for some purpose.

We are left with some unknowns here. We don't know the actual dimensions of the room. We don't know how many ppl were ultimately involved. And Kathy has never told us (despite being asked more than once) what the end purpose is for these recordings. Apparently the client is now thinking about improving the room; again, we don't know why! Does the client want better conference space? Does the client want to make more recordings? Etc.

Would actual multi-track recording be an option in the future? It would certainly be costly for Kathy. She'd have to buy (or rent) a slew of mics and some sort of multi-track recording machine. It would cost a heck of a lot more than her present outlay. So there's the financial question: it is worth it, in terms of how much she can earn from this client?

Also, does she want to deal with this much complexity, and mixing down a zillion-channel master? Is the added complexity worthwhile, again in terms of potential income?

How does the client feel about having a gazillion wires snaking all over the table? How many participants will be involved the next time? What if there will be 24 ppl? 30 ppl? 36ppl? Etc. etc. It starts to become physically and financially unwieldy.

To answer your specific question: every lav will pick up every sound in the room. A given lav will pick up its respective person the loudest, and everyone else at progressively decreasing levels as the distance increases. But in the final mix, you would use only one lav/track at a time, so that's as good as it gets.

Yes, clearly the book shelves are a partition between the room in question and the rest of the building. That appears to be the only visible walkway to get to the rest of the building interior.

In my opinion, the real problem is the room. If they want to record frequently in that room, I feel they really need to fix the room. Then it will be possible to get a more reasonable recording without one-for-one micing every participant. That will involve, at the least covering a lot of the long wall in some way ... either with permanent panels, change in construction, folding portable panels, etc. That will at least somewhat change the appearance of the room ... either for the duration of the shoot, or permanently. "Ye canna defy the laws of physics."

Re: Microphone for recording a round table discussion
 

Perhaps not a viable solution to Ms. Smith's situation, but I remember a discussion in one of the audio forums I frequent (possibly this one, but probably another one). One of the people who produced this documentary on Thorium reactors as a clean and safe power source recounted how he hacked a bunch of little dirt-cheap audio player/recorders to serve as self-contained clip-on mic/recorders. They were apparently cheap enough that he put two on each person (for backup redundancy) and just let them run all day. Then he had a complete dialog recording from each person that could be downloaded and dropped into the timeline of his NLE.

You can see in many shots in this video the little audio gadgets that he hacked. They are clipped on to the shirts/pockets/lapels/collars of the subjects. To my ear, the audio from this very ad-hoc documentary is quite above average in quality despite the "cheap as chips" (BrEnglish) or "dirt-cheap" (AmEnglish) audio solution. Does anybody remember this discussion of how they did audio for this doco?

https://youtu.be/xIDytUCRtTA?list=FL...4X_6kqWtVYE4kQ

Re: Microphone for recording a round table discussion
 

I'm sorry that I didn't say but I still don't know what the final purpose of this recording is. I don't think they know themselves. They were 13 people. At first I was told there would be 8 but then they said 13.
None of them have seen or heard the recording. I set their expectations really low. In the end they said as long as they get something that would be good enough!!! So, the fact that they want to improve things is based solely on the fact that I told them that the sound is not good. They just wanted to know if they could make little changes to make things better. They are not hoping to convert this space into a sound recording studio. They will not be holding conferences in that space. It's meant for occasional, intimate conversations over drinks, which will most likely end up on the web.
They are willing to buy a rug, hang stuff on the walls and perhaps hang a curtain on the glass wall but that's pretty much it. In the future, if they find themselves doing more and more events in that space they might rethink things but for now that's it. And yes the bookshelf is a half wall. They will not consider altering the space as it's a historical house.
As for using lavs on every person, it would be hard for me to do by myself. The way things are organized it's not a conference where everyone shows up and they start on time. This is more like people come and go in the middle of the conversation they get up to get drinks etc.
I will try to post a sample of the recording later.

Re: Microphone for recording a round table discussion
 

Nobody needs to worry about turning that space into a recording studio! They'd need treatment on all four walls and the ceiling to achieve that goal! Right now the reverberation time is longer than ideal even for conference room use. (By the way, can you give us the approximate dimensions of the room? I'm guessing about 30' x 15' x 10' high.)

There is a type of wood (or metal) trim called "picture rail." It comes in various contours, one of which is shown in these photos:
http://abeautifulmess.typepad.com/.a...81ef490970d-pi
https://s-media-cache-ak0.pinimg.com...a06820459f.jpg

You'll see it in a lot of art museums and galleries. Note the metal hanger shown in that photo, which can be hooked onto the rail at any point. The process is that you install the picture rail permanently on the wall, pretty near the ceiling, and paint it to match the wall. Then you use the hooks to hang things temporarily, without needing to make any further wall penetrations.

If your client mounted picture rail, at least on the long wall, and then got enough 6' x 2' acoustical panels to pretty nearly cover that entire wall, it would help a great deal. They could get custom panels with a color of their choice ... either to blend with the wall, or to complement it. And if they wanted to project an image at some point, they could just take down a few of the panels, to create a "projection screen" area of the wall.

Depending on the weight of the panels, they could be hung from the hooks using nylon monofilament, or braided wire, or paracord. If art museums and art galleries aren't offended by this hanging procedure, surely your client could stand to hang some *temporary* panels. Be sure to stress the "temporary" part ... get them away from their fear of "disfiguring" the room. When you take away the panels (and hooks), all that's left is a very unobtrusive piece of molding that pretty much looks as if it belongs there anyway.

They could also get some matching folding acoustical panels, which you could stand in a zig-zag pattern in front of the short wall behind you when you're shooting. Setup would be quick and easy, and it would look as unobtrusive as possible.

All in all, this might be less than the ideal amount of treatment that this room needs, but it's the best compromise I can think of at the moment.

Re: Microphone for recording a round table discussion
 

That's a Sansa Clip. I love them and have used them on and off for several years. I'm pretty sure I've recommended them on this forum, and have recommended them to other folks as well. You can literally clip one on the mic wire of a podium mic, for example. You can clip one inside a shirt or suit-coat pocket, and it will be barely visible; yet the mic is on top, peeking out of the pocket, so you get good audio.

I'm not sure what mod would have been done (or how) unless he installed the Rockbox third-party firmware which does make some improvements. Out of the box, they record mono, WAV, 16bits/sample, 24kHz sampling rate. There's no recording level metering, but they're pretty hard to overload with normal conversational voice levels. You would not want to use one at a sporting event with a shouting crowd.

Unfortunately the original Clip (internal memory only), and the Clip+ (which accepted a microSD card) have been discontinued. I got a handful at great price from the local RatShack when they closed. I wouldn't mind having a few more. Some later versions of the Clip (e.g. the Clip Zip, Clip Sport, etc.) are in current production.

BTW I never saw this video before, and I've followed this forum regularly for several years, so I suspect you originally found it elsewhere, rather than here. It's a great find ... thanks for sharing!

Re: Microphone for recording a round table discussion
 

For a temporary relief with a non-permanent installation, reasonably easy to deploy and demob, here are some thoughts for any surfaces that are out of shot:

Glass area: one could use re-useable suction cups with hooks:
Mudder 45mm Bathroom Kitchen Suction Cup Wall Hooks Hangers, 12 Pack for $7.98
Find some used curtains, maybe shears to let some light through if necessary.

Walls: If smooth, one could use more suction cups, if textured then use a backdrop system.
Neewer Pro 10x12 feet/3x3.6 meters Heavy Duty Adjustable Backdrop Support System Photography Studio Video Stand with Carrying Bag for $69.99
A backdrop system is very portable and reasonably easy to set up.

Floors: spread out some old blankets where they don’t walk because they could be slippery. Blankets would be easy to move and take up minimal storage.

For shots that inadvertently get a bit of the sound treatment in view then use the Ken Burns effect.

Re: Microphone for recording a round table discussion
 

the room is 40'-20'
I'm interested in hearing more about the curtains Richard mentioned. Richard do you have any specific info?

Re: Microphone for recording a round table discussion
 

Yikes, that's bigger (therefore worse) than I had guessed. I'll bet the reverb time in there is several seconds.

Re: Microphone for recording a round table discussion
 

It is quite literally a trade-off between what the owners of the space will allow (aesthetically), what the decorator can provide, and how much acoustic absorbance you can squeeze out of it.

I had in mind something like this "Austrian balloon curtain". In a sheer colorless fabric, it would still let in a lot of light and not "block" the open feeling of the window wall. But all that semi transparent fabric is also semi-transparent to sound, and the spaces created by the folds would absorb some of the ambient sounds both traveling on their way to bounce against the glass, and as they reflect off the glass and back into the room (and your microphones). The rounded, uneven patterns would make an interesting contrast to the stark design/decor of the rest of the room. I am not a decorator, nor do I play one on TV, but I know what I like. :-)

And I would lobby hard for hanging some kind of fabric feature (even if it is all white) anywhere on the opposite wall that isn't being use for protection. And for some of those big thick shaggy faux-fir carpets.

Re: Microphone for recording a round table discussion
 

Richard, that's a very interesting curtain. I've never seen anything like that. Of course I don't get out much. ;-) It does appear fairly transparent, especially at the top where it's just one layer. Actually a rather nice effect: it lets you see the sky, yet somewhat blocks out the view of "man-made stuff" at the lower part of the curtain, especially if it hangs all the way to the floor.

I doubt that it would do much at the low end of the spectrum (which makes the room boomy), but it might help a tiny bit with the higher frequencies, and those are the ones that affect intelligibility. Still, the fabric looks very light in weight. Do you have any published acoustical specs for that kind of hanging?

Re: Microphone for recording a round table discussion
 

Richard,
These Austrian sheers are very nice and an nearly every home uses them. The help to reduce the amount of stark daylight while still allowing for a view out the window.
I don't know why homes in the US don't use them more. Here is a listing of shears on an Austrian web site similar to Craigs List in the US: https://www.willhaben.at/iad/kaufen-...ne+wei%DFer%2C

Don't know if just clicking on the URL will or if it has to be cut-'n'-paste.

Re: Microphone for recording a round table discussion
 

Thanks Richard for showing the curtain. Unfortunately this design doesn't go with the original design of the house.
What a bout something like this?
curtain

Re: Microphone for recording a round table discussion
 

Kathy, those are very nice looking, and would certainly look appropriate in that room. Based on the graphs shown in the .pdf file, they are surprisingly good acoustically, especially the Formoza fabric. If your client would be willing to cover the entire window area with Formoza, that would certainly be an improvement over bare glass.

Of course they could cover the long wall with the same fabric, and get twice the improvement. The look would then be consistent. And if they needed some projection area, they could just open the wall drapery in the middle.

Re: Microphone for recording a round table discussion
 

That would likely help the lighting as well by defusing the harsh outside light. Though I'm not a lighting or camera person but I usually work with some really good folks.

Re: Microphone for recording a round table discussion
 

Is this just one of those situations where the solution is a lav mic on everybody, and multitrack the audio to edit later? I can't see even that expensive solution being more than treating the room and using distant techniques. Close in or nothing, I guess?

Re: Microphone for recording a round table discussion
 

I agree that the absolute best sounding solution is probably separate lav on separate tracks. But the OP has explained in detail (last paragraph in post #59) why that is not an option in this situation.

Besides, it would come down to a choice between the client spending some money to improve their own problematic room, vs. the recordist spending money to solve the problems created by the client's room. The client has asked the OP (post #45) for suggestions on improving the room. If the client is willing to improve their room, by all means take that approach first!

So yes, "in the best of all possible worlds" (as Candide would say) go with separate lavs on separate tracks ... but in reality, from what the OP has said, that ain't gonna happen.

Re: Microphone for recording a round table discussion
 

Here are 2 audio samples from the recorded conversation. The first one is someone who was sitting a bit closer to the mic than the person in the second recording.

https://www.dropbox.com/s/t1gfiwb0oc...o%201.wav?dl=0
https://www.dropbox.com/s/jlt55ew5wf...o%202.wav?dl=0

Re: Microphone for recording a round table discussion
 

Also, I came across interesting looking acoustic panels, what's your take on these:
Snowsound USA Acoustic Panels |

Re: Microphone for recording a round table discussion
 

The "Oversize" product looks most appropriate for soaking up sound and minimizing reflections in your echo-chamber room. The other products that BLOCK sound from one cubicle or area to another are not really as effective in your space.

Many people have made simple "shadow box" open frames, covered them with one of dozens of colors of double-knit polyester (solids, patterns, etc.) and put loose-fill absorbent material (fiberglass, polyester, etc.) inside. By choosing a fabric color the matches the wall color, the visual impact is minimized and only adds a subtle geometric feature to the otherwise big blank wall.

But it could make a huge difference in acoustics. Note that it will not only improve acoustics for recording, but it will also increase the intelligibility of speech in the room for all the participants.

Re: Microphone for recording a round table discussion
 

Thanks Richard. Yes, I didn't think any of the cubicle things would be effective in this case. I'm wondering about those ceiling panels. Would they be better than nothing on the ceiling?

Re: Microphone for recording a round table discussion
 

The two recordings sound exactly like they are - distant mics in a room with hard surfaces. Are either acceptable to you? If they are not, then you have to spend money. On equipment, treatment, people to work the kit etc.

We seem to be looking at a magic bullet to solve the problem, in any place the people are in the room.

If you treat the room, and turn it into an anechoic dead room - then you still have level changes to deal with if you have multiple sounds sources, each with different speaking voice levels.

Are we talking hundreds or thousands?

Re: Microphone for recording a round table discussion
 

A boundary mic 1/4 of the way along each table ( so 4 mics or one between 2 participants ) and fed into an Audio Technica Smart Mixer which will automatically open and close individual mics as required .

http://www.audio-technica.com/cms/mi...e0f0833b22a45/

These 4 channel units can be daisy chained if more microphones need to be added . Any good hire company will have them for modest daily charge - I used to use them to record conferences and they work really well .

Edit - they can be picked up used

http://m.ebay.com/itm/112166413659?_mwBanner=1

Re: Microphone for recording a round table discussion
 

I have a couple of Shure Fp-410's which can do an Automix. They have been replaced by this model .

https://www.bhphotovideo.com/bnh/con...C&A=details&Q=

I have used matching Lavs, booms, and table mics depending on whether you can mic individuals or just need general coverage.

Re: Microphone for recording a round table discussion
 

That looks almost like a clone of the Smart Mixer !