mettelus
Dynamic mics are great for noise reduction, but that also includes the front. When you say "constant level" from a room, you can literally scream into a dynamic and not peg it at 1m, so at 3-4m things can easily drop off the radar.

That was my theoretical deduction from the experience with "normal" cheap/mid priced dynamic mics.
 
But I guess Wren's choir is unlikely within 1m from the mic. And I interpret Jim's proposal as not giving every person in the room personal SM7b, more like covering some area (not the whole room, but also not 20cm) with it.
 
Both systems already have 3 personal (dynamic) mics, one wireless for the talking person, another wireless for questions and additional wired for the convener. The problematic is discussion part, when several persons say something, sometimes in parallel sometimes as a dialog.
 
* Moving the mic every time does not work (and also dangerous not only for people but also for mics... we have glued them several times already, after "hot" discussions  ).
* one directional mic per person and activation buttons (we have such system at one location, with ~50 mics) require fixed tables position and still does not work well during discussions (people forget to press the button or turn away from the mic)
* Policom with 2-5 satellites works ok, but again require fixed tables, inform remote end about "typing" on any notebook near the satellite  and  when someone turns a bit or sit in the "second row", the game is over.
* in addition I have observed several commercially installed custom systems which do not work at all (including one with mics positioned 1m in front of large speakers LOL)
 
The result: at least a half of any discussion is not audible remotely, introducing major inconvenience and misunderstanding (taking into account international nature of participants, including people which barely speak/understand English).
 
It seems like this area has big gaps between pro-audio scene like Radio/TV, where the quality has priority over money and required personal,  commercial "high level" conversations with just several participants in dedicated specially prepared rooms  and Teamspeak/Skype like systems to call parents and play on-line games.
 
And so I have decided to re-invent the wheel using music equipment, with a possibility to connect several types of mics and shape the signal with EQ/Comp.  So construct mid-priced system specially for our purpose.
F.e. rack mixer without physical controls is a life saver since "participants" tend to turn/push everything they can when something does not work as they expect (obviously without any idea about consequences).
Fixed mics on the wall/ceiling are also important. If something is laying on the table, people will sit on it and put coffee inside it. And for sure it will be on the floor when tables are moved. 
That sound unbelievable assuming all participants have (or moving toward) Dr. / Prof. prefix in there names, but that is reality...
 

If you are trying to build a conferencing system then you probably want several microphones, and a DSP that includes "Acoustic Echo Cancellation". Microphones from A-T, Shure, Clock Audio, and others are all usable, polar pattern will depend on the room and the placement of the microphones in the room. Polycom makes a ceiling microphone that works really well, especially in spaces that are not properly treated. And if you have the budget Shure has a ceiling microphone that is steerable - incredibly cool, but not for the budget conscious.

For DSP you should probably consider Polycom SoundStructure, QSC Qsys, Biamp Tesira, and BSS Blu, not in that  order. My current favorite for straight conferencing is the Polycom (although I really wish they'd add AES-67 or even Dante as an input), and Qsys for more complex projects.

You can find used Biamp Audia processors on eBay for very little money. If budget is a concern (and when isn't it?) that is a very good solution. While they are discontinued, we built the AV system for an entire convention center using Audia. It was really pretty cool!

Hope this helps!

That sounds interesting, but I have failed to find any prices for MXA... which usually means they are outside the budget
The communication platform is in fact fixed: https://www.vidyo.com/ . They have forced and not tunable processing.
 
I understand there are top hardware solutions. But I do not think colleagues will understand me in case one end point will cost more then $1-3k (total). Usual connections are just with headsets, Logitech usb mics or ~$500 Policom points. People here would like to have something a bit better, but they do not immediately ready spend 20x more for that. I have also mentioned bad constructed systems (~$5k), I mean there is in general no confidence the money are not for nothing. Over $10k is definitively no go, even in case it works for sure.

Have you considered lapel mics? A decent lapel mic with either a built in gate or gated in software should allow everyone to be heard. I'm not sure how loud the sounds in the room are or the dimensions of the room. This could all affect the outcome. In most situations lapels work well. Some wireless lapel mics share a common channel so you might not need to mix multiple channels.

Starise
Have you considered lapel mics? A decent lapel mic with either a built in gate or gated in software should allow everyone to be heard. I'm not sure how loud the sounds in the room are or the dimensions of the room. This could all affect the outcome. In most situations lapels work well. Some wireless lapel mics share a common channel so you might not need to mix multiple channels.

I am not sure I understand you right. Are you writing about wireless personal Lavalier mics?
We already use such for the speaker (the room size, the number of persons and current devices in use I have already mentioned before).
But how that can be applied to a room with 10-30 persons inside?
I have mentioned that ~50 stationary mics more or less work at one place. But not for rooms I try to equip now.

azslow3
That sounds interesting, but I have failed to find any prices for MXA... which usually means they are outside the budget

 
I believe the MXA line of microphones is only available through distribution, you'd need to contact a local integrator to purchase. And yeah, they are probably beyond your budget, among other things the use Dante or AES67 for audio, so you'd need a DSP that speaks Dante or AES67, or you'd need D/A converters.
 

azslow3The communication platform is in fact fixed: https://www.vidyo.com/ . They have forced and not tunable processing.

My condolences - I spent three years supporting their VTC solution, and it was a nightmare. I think they have a great idea (somewhere between soft codec and codec) but their implementation was anything but stable and reliable. Good luck!

azslow3

Starise
Have you considered lapel mics? A decent lapel mic with either a built in gate or gated in software should allow everyone to be heard. I'm not sure how loud the sounds in the room are or the dimensions of the room. This could all affect the outcome. In most situations lapels work well. Some wireless lapel mics share a common channel so you might not need to mix multiple channels.

I am not sure I understand you right. Are you writing about wireless personal Lavalier mics?
We already use such for the speaker (the room size, the number of persons and current devices in use I have already mentioned before).
But how that can be applied to a room with 10-30 persons inside?
I have mentioned that ~50 stationary mics more or less work at one place. But not for rooms I try to equip now.

Yes, what you call lavalier mics. 10 to 15 people might be possible. 30 would begin to require a lot more and make things complicated. Not impossible just more complicated. The reason I mention this type of mic is they usually have a built in squelch/gate circuit and if you notice these are used with perimeter mics a lot in television broadcast interview situations because they are good at rejecting the wrong sounds you don't want to hear. Also used frequently in drama stage acts so you don't pick up the person coughing from the stage. Another advantage is the user can get up and walk around to a display board and you won't lose their audio.
As you may know there are different grades of these mics, some work better than others. Unless I misunderstand multiple people want to speak in a group meeting.  If it works for one speaker, why not for everyone else since they are all speaking at one time or another? The main issues here being to make sure there is no interference with adjacent frequencies.
Another option would be PTT mics.
 

wst3

azslow3The communication platform is in fact fixed: https://www.vidyo.com/ . They have forced and not tunable processing.

My condolences - I spent three years supporting their VTC solution, and it was a nightmare. I think they have a great idea (somewhere between soft codec and codec) but their implementation was anything but stable and reliable. Good luck!

That is nothing I can change... They have found the "back door" to https://home.cern/ and have replaced previous (telephone only, but working well) provider. First 2 years many meetings was just cancelled... But they have improved with time, no more "funny meetings" (like 50 people connected to the same conference ID was in 2 different rooms... someone had to connect multiple times from different computers to join both rooms and "bridge" the audio :) ).
 
Thanks to the "agreement" with MS, all software should be compiled also for Windows (which make no sense). Thanks to Vidyo we do not use anything else for conferences
 

Starise

I am not sure I understand you right. Are you writing about wireless personal Lavalier mics?
We already use such for the speaker (the room size, the number of persons and current devices in use I have already mentioned before).
But how that can be applied to a room with 10-30 persons inside?
I have mentioned that ~50 stationary mics more or less work at one place. But not for rooms I try to equip now.

Yes, what you call lavalier mics. 10 to 15 people might be possible. 30 would begin to require a lot more and make things complicated. Not impossible just more complicated.

The one for the speaker is already one more then I would prefer... May be you have not seen what people can do with mics if they have a possibility to touch them 
 

  Another advantage is the user can get up and walk around to a display board and you won't lose their audio.

That is the target of my new system! But without giving the person any mic... And as I have written at the beginning, that is working. Just not perfect.
 

If it works for one speaker, why not for everyone else since they are all speaking at one time or another? The main issues here being to make sure there is no interference with adjacent frequencies.

Apart from probably replacing at least one cable per day... Accu in half of them will be empty at the beginning of every day. For 2x wireless mics we use 4x sets of accus + batteries laying around, just in case. And still there are times when there is one working mic only, the one which is wired.
 

OK azlsow I tried. My advice was free and maybe that's how much it's worth to you. You know what doesn't work. Now maybe you can narrow what might work.
There are only so many different kinds of mics and ways to mic people. We have covered most of them here and none of them will seem to work. What now?
I mentioned PTT mics. These only work when you push a button. All mics either have cables or batteries. No getting away from that one.
I wonder if the space could be changed..seems like a very bad place to hold a long distance video conference
I don't know all of the fine details. I do know this-
A. There is noise in the space
B. You don't like people touching mics
C. The space is smallish for a larger number of people
D. There is no magic wand
 
The outside noise can only be tamed with polar pattern, mic design, less noise, gates, or a combination of those.
 
 
I use mics all the time both in the studio and in live performance so yes, I know what happens when people touch mics.
 

Starise
OK azlsow I tried. My advice was free and maybe that's how much it's worth to you. You know what doesn't work. Now maybe you can narrow what might work.
There are only so many different kinds of mics and ways to mic people. We have covered most of them here and none of them will seem to work. What now?
I mentioned PTT mics. These only work when you push a button. All mics either have cables or batteries. No getting away from that one.
I wonder if the space could be changed..seems like a very bad place to hold a long distance video conference
I don't know all of the fine details. I do know this-
A. There is noise in the space
B. You don't like people touching mics
C. The space is smallish for a larger number of people
D. There is no magic wand
 
The outside noise can only be tamed with polar pattern, mic design, less noise, gates, or a combination of those.

There are several interesting approaches in this thread. And am going to try them.
Your proposals also make perfect sense, we already use lapel and PTT mics with success. I have just mentioned the reasons why I think that is not scalable for my current wishes.
You are right, all mics either have cables or batteries. But that is why I want to cover the room (complete or as in some proposals just small areas). That approach use wired mics without fixing them on the table nor on people.
 

I use mics all the time both in the studio and in live performance so yes, I know what happens when people touch mics.

I hope in the studio and on stage people do not do the following:
* using a mic like a peak, so pointing it away from himself; attempting to lay down round mic on table (so it rolls and at some point fall); forgetting they have mic in the hand (with all possible consequences)
* continuously grab lapel mic; refusing to attach it and its transceiver, attempting to hold all that in one hand, which also tries to do something else in parallel
That sounds like a joke. But I know several people which chair several meetings per week, years long, yet they still can not handle personal mics correctly.