Lecterns and Pulpits

[Solstace]

Greetings!

 

Something playing on my mind for several months... For someone talking at a podium, some events seem to have two mics (one mounted on each corner of the podium, pointed effectively upwards and through the centre of the podium). Others seem to have just one mic, mounted centrally and (hopefully) just in front of the speaker's mouth.

 

Question: Why use two mics? What bothers me about this approach is that due to the angle of the mics, there are phasing/timing issues between the signals appearing at different times to either mic, the mics will likely have more of the FOH mix in "hearing range" and probably are less direct with regard to the person speaking.

 

So - I'd prefer one central mic in that situation - it'd dead obvious to the speaker where the mic (and pickup zone) is, also a single point source reduces timing/phasing issues coming into the PA from the source itself.

 

While I can come up with plenty of things to try that would probably work very well in the contexts I have in mind, it's something that many of my engineers have divided or ill-formed opinions about. I therefore just wondered whether anyone out there has any better-defined/explained thoughts on how and why either approach could be used, and whether any other equipment (gates/automixers/compressors) ought to be used to get the most out.

[benweblight]

Sometimes one is used as a backup in critical applications (I.e VIP).

Also I believe some people mix between them as the speaker moves (which they do apparently).

 

Recently discussed here: http://www.soundonsound.com/forum/showflat...;fpart=1#501452

[Bryson]

I thought this was pretty obvious. In any sensibly shaped room, the audience will be too wide for the speaker to get them in a single eyeshot, and so will sweep his head from side to side to make eyecontact with them all at some point. With a single mic, that's going to be a problem. With two, you have a much larger area of pickup that works.

 

Don't make the mistake of assuming that the speaker knows anything about mics and will talk into it!

[Simon Lewis]

The two mic scenario satisfies the redundancy criteria, and the "we've seen this on TV so it must be the right way to do it" criteria. It almost meets the "cover the person speaking across a wide lectern" criteria, but if the 3:1 rule is broken (distance between mics to distance to person) then it's likely that you will experience comb filtering.

 

The more savvy engineer realises that two mics is a good backup, so he ties the two capsule together at a central point, and ensures the pickup pattern is wide enough to cope.

[Shez]

I ride the levels on them so they're never both on at the same time. If the lectern is at one side of the stage, the speaker will predominantly speak towards the middle of the audience which is off centre - the mic on that side will see the most action. And yes, the person speaking will move around lots and pay no regard whatsoever to whether they're anywhere near a mic or not...

[griffter]

Hi,

 

I would agree about trying to keep the two mics fairly close for phase coherence. Sometimes a technique I use is to Ring out one of the lectern mics and keep the other one flat, Mixing in a bit of the flat one can give you some fullness and warmth back into the speech.

 

Regards

 

Griff

[mac.calder]

I have had clients complain when they have only had one mic on a lecturn (we use 412's and 418's on Lectrum L100's so every time they see this style of lecturn on TV, they are used to seeing two mic's).

 

It is a bit of a "Monkey see, monkey want" scenario.