Advice on mic placement etc

[bruce]

Looking for some advice on mic placement etc.....

 

The scenario. An amateur panto in small village hall. Cast of adults and kids. Adults voices can project (a little), but kids struggle.

 

Hall seats a couple of hundred. Relatively wide, almost square, with very low ceiling. Stage is a small "box" insert in one wall,about 12 feet deep, with a platform which extends about 8 feet in front of the curtain into the hall, raised about 12" from main floor level. Stage extension is home-made, and rather noisy when people walk on it. No installed sound or lighting systems.

 

No radio mics and no budget.....

 

Not a very encouraging start, is it :-)

 

 

So what's the best way to mic this lot then? It sounds like it shouldn't be too difficult, but the venue seems very prone to feedback. It's apparently not just me - I know of a band who played there recently and had similar problems.

 

I did a quick test using 3x cardioid condensers - can't remember whether I used AKG CK91s or Samson C02s - about 3 feet off the ground, along the front of the stage. Speakers were a pair of Celestion SR-1s , positioned at either side of the hall, about 12 feet from front wall, so they were about 4 feet in front of and 9 feet to the side of the nearest mics.

 

But I had real trouble getting any reasonable gain without feedback. Tried moving the mics and speakers a little, and tweaking the EQ, but no real improvement.

 

As I said, this was a very quick test - I only had access to the venue for about an hour, most of which was spent setting up, so I only had about 10 mins to experiment. What do you reckon would be the best way to proceed?

 

Changing mic placement? Changing mics? raising them? hanging them? Moving speakers? Additional speakers further back in hall, so less gain required?

 

The mics I have available include half a dozen cardioid condensers (Samson C02s and AKG C91s) and a couple of AT871R boundary mics, running through a Mackie CFX desk. I also have access to a Behringer feedback destroyer and a pair of Roland AF-70 feedback exterminators.

 

All advice welcome!

 

Bruce.

 

ps - any comments on the relative merits of the behringer vs roland feedback destroyer? I've not had a chance to do a side-by-side comparison. Which would you prefer?

[IanG]

Not a very encouraging start, is it :-)

 

It's not too bad - we all have to start somewhere and it sounds like what you have should be enough to give a workable solution.

 

I did a quick test using 3x cardioid condensers - can't remember whether I used AKG CK91s or Samson C02s -  about 3 feet off the ground, along the front of the stage. Speakers were a pair of  Celestion SR-1s , positioned at either side of the hall, about 12 feet from front wall, so they were about 4 feet in front of and 9 feet to the side of the nearest mics.

 

 

My attack with your setup would be as follows, but it depends a bit on the exact setup of the hall so play about a bit if you can.

 

Stick your AT871R boundary mics on the front lip of the stage, about 10cm in and with a bit of foam or similar underneath them to reduce the sound of footfalls. If you have a band on the floor at the front of the stage it may be worth building a small screen with MDF or perspex to place behind the mics. Engage the high-pass filter on the desk if it has one.

 

As you have three feedback destroyers, use them all :-)

 

I'd put the two Rolands on the insert points for the two boundary mics as they are the same. I'm not familar with them but if you can set them in one-shot mode - then before the show begins crank each of the boundary mics up in turn and let the feedback destroyer lock on to the frequencies. This should give you 3-5dB of additional headroom.

 

Have a look at what the feedback destroyers have done - if you have 6 filters all set at about 2kHz (for example), take a bit of 2kHz out with the desk EQ and re-do the destroyers - they're generally better at doing narrow cuts than wide ones and it makes sense to do one wide cut on the desk than multiple narrow ones over the same range on the destroyers.

 

Have someone stand on the stage and speak - if it sounds too 'airy' (as boundary mics sometimes do) turn down the HF EQ.

 

Then I'd make the most of a pair (or three on a wide stage) of your condensers and rig them further upstage above the stage, angled slightly so they'd be pointing at the cast's mouths rather than the top of their heads. Resist the temptation to put all 6 up there - the more open mics you have the less gain before feedback you can use.

 

Route those to a subgroup on the Mackie and put the remaining feedback destroyer in there, and repeat the process above.

 

You then should have 4/5 mics which should give reasonable results. Try to stick to using as few as possible at any one time as the more that are open, the more chance of feedback.

 

Additional speakers further back in hall, so less gain required? 

 

That's a trick I use sometimes, especially when there is a thrust before the front of the stage and there may be action in front of the main speakers. If your second set of speakers are any more than 10m (ish) in front of your first set you might need a compensating delay.

 

ps - any comments on the relative merits of the behringer vs roland  feedback destroyer? I've not had a chance to do a side-by-side comparison. Which would you prefer?

<{POST_SNAPBACK}>

 

I've used neither so can't comment - however I do use the Behringer DEQ2496 for system EQ, parametric (ie. anti-feedback) EQ and delay and I think it's the mutt nuts :-)

 

Hope this helps.

[Just Some Bloke]

The Behringer feedback destroyer should be useful if set up correctly. It needs to be patched in over the mic sub-group and pushed so one frequency at a time feeds back. It will then destroy that feedback. Having let it find the first frequency then push the level higher so a second appears and let it find and destroy that, and so on until it's found 12 or so frequencies. This should be done before you start any other soundchecking.

 

Mics wise, most theatres use narrow angle mics (called rifle mics or shotgun mics) to go along the front of the stage rather than cardiods as they'll stand less chance of picking up the sound from the speakers, and thus less chance of feeding back. If the apron stage is noisy, don't put anything on the apron itself, use stands in front of it. The boundary mics might work well on the real stage, though, to pick up sound from the people behind that front row of mics.

 

Speaker placement is, at least, in front of the mics which is good. Perhaps you need to angle them out a bit? Make sure you don't lose sound to people in the middle, though. If you're only putting the mics through the speakers, don't forget that the front few rows of audience will probably hear the live sound quite well and won't need amplification, so maybe you could move the speakers further into the room, ignoring those front few rows. This wouldn't work if music or sound effects are also amplified.

 

Hope you have better luck second time!

 

JSB

[bruce]

Thanks for the advice chaps..... It reinforces what I had been thinking....

 

I've used the roland feedback exterminators (http://www.roland.co.uk/prodcatdetail.asp?id=AF-70) before, and they seem fairly effective. In standard mode, you hook them up, push the gain up until feedback is threatening, press the "Start" button, cover your ears and let it train... It has ( I think) 8 filters. The manual is also much more understandable than the behringer :-) Putting them on the boundaries seems sensible.

 

One interesting feature is that they have XLR inputs with switchable mic/line gain, and phantom power! So you can either use them on an insert, or connect a mic directly to it. Most unusual....

 

The Mackie CFX desk that I'm using has 4 subgroups, but it doesn't appear to have any proper inserts on the subgroups! There are inserts on the individual channels and on the main out, but not the groups. I reckon I can get round this by routing the non-boundary mics to (say) group3/4, and not routing this to the main mix. I would then take the group outputs, via the FB destroyer, back in via a FX return, routed to main... tedious, but it should work.

 

Mic positioning - I'll experiment....

 

Thanks for the advice.

 

Bruce.

[James]

What are you trying to do?

 

Why is re-enforcement necesary.

 

If the children are as bad as you make out at projecting then the best rung out boundary mics in the world cant help them.

 

If this is for re-enforceing dialouge that cant be heard then I would

 

1) reduce all ambiant noise, music, fans etc.

 

2) work out how far down the hall the un re-enforced dialouge carries.

 

3) I would recomend placing your speakers at this point, remember that the further you can place the speakers from the stage the better GBF you get.

 

4) KIS

 

Good Luck

 

James

[Paul J Need]

I have to agree with James 110%

 

Little voices are just that - little. Start off with a small sound being produced at the same time as a louder sound - and you end up with the same differential. Adults being heard - kiddies not!

 

As James says......... go figure where the natural sound reaches to, then install your first speakers a little in front of this position. (A DDL would be handy at this point.) As the speakers are now so much further away from the microphones - your GBF problems are reduced. Don't forget also. the more mics you use the more problems you create. Forgot the exact sums, but adding a second mic reduces the overall gain by 3dB etc etc........ So use the minimum amount of mcirophones required.

 

A combination of Delay, graphic and subtle re-inforcement is your best option.

[Ellis]

Before questioning the need for reinforcement, don't forget that when you get amateurs and kids trying to compete with a band (or sometimes even just a piano) you often find that the singers loose! Especially when the musicians are amateur too.

 

If the music is from just an electronic piano, try taking control of the piano level. That way, you can get a good balance by reducing the pianists level. Give the pianist foldback on headphones and you can give them whatever level they require.

 

You could even ask the band to play quietly (all pigs fed and ready to fly).

 

good luck

 

Ellis

[bruce]

Resurrecting an old thread where I asked for some advice on mic placement, I thought I should report back - and thank everyone for their advice!

 

After some trial and error with boundary mics and hanging mics, I eventually went with a very simple setup. Sometimes less is more :-)

 

I found that 3x condensers across the front, about 4' high, feeding a pair of Celestion SR1s FOH and a second pair of speakers further towards the centre of the hall made the stage dialogue audiable for all of the audience, except for when the 2 quieter-voiced kids were speaking. So I gave them a pair of radio mics.

 

Distance between front and centre speakers wasn't enough to require a DDL, but did mean I could drop the gain on the front pair significantly.

 

The advice about keeping the band under control is good. Fortunately, all of the music was pre-recorded, so that was easy :-)

 

.... and it all worked. Got lots of good feedback (pardon the pun!) afterwards. Cast happy, audience happy, and somewhere in the region of 1500 quid on it's way to the tsunami appeal....

 

Bruce.

[Bobbsy]

Glad it worked for you...and happy to hear where the money went!

 

One thing you might like to consider for next time....although you got away without a delay unit, if you'd managed to obtain one you might have found that it did improve the intelligibility and sense of "direction" in your reinforcement.

 

In "back of the envelope terms", each foot of distance the speakers are in front of the original sound source adds about 1 ms delay. In a small hall, this might not result in objectionable "echo", but, due to a psycho-acoustic trick called the Haas Effect, if you can delay your speakers to arrive slightly after the non-amplified sound from the stage, the speakers seem to disappear and all the sound appears to come from the original source.

 

As I say, the 1ms per foot rule is only a rough guide...you'd tend to make this adjustment by eye/ear using the calculation only as a starting point. However, as you dial in the delay, the effect when you hit the right point can be quite startling to behold.

 

....and if I'm being over simplistic for you or pushing my nose in where not wanted, I apologise!

 

Bob