Need an advise about mics.

As a home player, I have used only cheap dynamic and large diaphragm condenser. I guess people here have experience with other.
 
I try to build more or less functioning internet conference system. And I have not seen even half way acceptable solutions. The only usable devices I could observe was from Polycom, with one extender per table. And custom build systems with personal mics.
 
What I want is sound pickup from the whole room. For the moment ~6x8m but next project is for ~8x15. The is not for music. It just has to pick the speech with constant level on output.
 
I currently test 2x large diaphragm condensers throw DM for gate, EQ and compression. The result is almost satisfactory, remote end get acceptable signal from any position in the room.
 
But there is one aspect I want to improve: the upper part of the room is almost covered by metal tubes, the room was constructed as a labor... Not only that horribly resonate and produce echo, the cooling system is super noisy (air moving throw uncovered metal tubes), especially at warm days.
The mics I use (at the moment not covered at all) take all sounds, including the noise, corridor, steps. So I am thinking about a possibility to limit the direction and/or distance.
 
I will appreciate any advise. May be another mic type, may be some kind of caves for existing. Modifying the room (I mean cover tubes and beton walls)  unfortunately is not an option.

Thank you for the reply. I will try high positioning mics.
Which polar pattern would you recommend for my scenario? I am using cheapest mics just to check the concept is working in general.
 
 

Is everyone sitting at a table or is this an open room with just chairs?  If everyone is sitting at a table, you might try boundary microphones.  They are designed to pick up the sound hitting the surface and are common in conference type settings.  For the smaller room you might need 2 or 3.  For the larger room you will need more depending on the size/layout of your table.
 
Also, I believe the Polycon type systems use boundary mics.

If the room was less problematic, the simple solution would be a LDC with "omni" polar pattern.  (Boundary mic would be similar)
 
Since the room itself is full of reflections and negatively affects the sound, you don't want to capture the "room as a whole". 
 
Given your circumstances, I'd look toward what radio stations use when dealing with multiple individuals in a room.
RE-20, RE-320 (modern take), and SM7b are very popular for this purpose.
All are large diaphragm Dynamic microphones... and will capture less of the room.
The RE-20/RE-320 are popular because they're extremely rugged... and don't color the sound a lot if the source is off-axis.  If you want to capture as little of the room as possible, go with the SM7b.
 
Many folks (in less than ideal home studios) use the SM7b precisely because it doesn't capture much of the room.
 
All three mics are useful for many recording tasks (vocals, kick, guitar/bass cab, etc).

The RE-320 is similar to the RE-20... but uses a Neodymium magnet (hotter output than the RE-20) and has an upper-mid presence boost. 
 
The SM7b was used for the vocals on MJ's Thriller.  

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...
 

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.

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

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.
 

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.
 

To be fair I see the predicament with lapel mikes. Batteries need to be changed regularly if they are wireless and people are rough with them sometimes or don't know how to use them. If done correctly any number of setup could still work though.
The place I work has several large teleconference rooms. I haven't looked at the gear there closely, but it looks as if they use some kind of gooseneck microphones on the table.50 people seems a very large number compared to the teleconferences I have seen. There usually aren't more than 15 people at any one locating.
 
Anyways...good luck. Maybe someone else will chime in with another idea.

I use a Samson UB1 for conferencing. Can't recommend it enough - it's been perfect for me.

azslow3

msmcleod
I use a Samson UB1 for conferencing. Can't recommend it enough - it's been perfect for me.

Thanks. An interesting device to try a boundary mics. Do you use it with Samson Sound Deck?
 
After the test yesterday, my conclusions is that not personal mics is the way to go in my case:
* 2 speakers was using lavalier mic, both have decided to not attach it to out neck, one had the transceiver in the same hand, effectively having the mic ~30cm away from the head (with obvious result). Another has fixed the transceiver on body, but still had the mic in hands. Articulating, so with 10-30cm distance.
* 2 speakers was using dynamic mic. Both was handling it strict vertical, so pointing toward ceiling. One ~10cm from the mouth, another ~20cm.
* the fact other could speak without giving mics or thinking into which direction to turn the head has improved the experience and the speed of discussions.
* almost everything was recognizable on remote end.
 
What was not good:
* central conference processing (so outside of my tweaking possibilities) was handling mode switch with cracks/several seconds too loud or almost not audible signal. I guess I have to balance the total input signal better (I currently just mute room mics, without adjusting personal mics levels)
* the natural room hall effect and the noise are on the very border of acceptable level. I definitively have to improve that (will try placing, caving mics, if that does not work other mic types).
 
During the next test I am going to try ReaFIR as real time noise reducer. If that works better, I will need to replace DM with a computer. But these days that is even cheaper then good quality mics..
 

I use it directly into my work laptop via USB. I use it mainly with Skype when conferencing with my colleagues in the US. It's way better than the conference mics we have in the office.
 
The best thing about it is it seems to have a built in compression and/or AGC, so matter where you are in the room, you get a fairly even level.