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Old March 24th, 2006, 04:29 PM   #1
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What mics do I need?

Mostly my footage is of Seminars and Corporate Events i.e. Speeches, Interviews, and the occasional Banquet afterward (where there is live music and some on-the-fly interviews etc. etc.).

I would also like to try and cover some of these events in 5.1 Surround using 5 mics to get 5 distinct audio tracks (following the layouts that I got from the Schoeps website due to responses from an earlier posting of mine).

I will in the future be shooting some live band and concert footage (staged) and would also like to try my hand at recording these events in 5.1 Surround with 5 mics.

What Sony mics could I / should I use to cover all of the above possible scenarios???

I had a look on the web and found a Sony F-740/9X mic that appears to be sort a sort of 'general purpose' unidirectional cardiod mic. Anybody have any experience with this range?

Regards,

Dale.

Last edited by Dale Paterson; March 25th, 2006 at 07:06 AM.
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Old March 25th, 2006, 07:08 AM   #2
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I don't have any direct experience with Sony's mics so I can't help much with specific recommendations but just a couple of general comments...

First, it may just be that your new mics are more accurate than the consumer mics. A lot of people tend to associate lots of bass with "good, full, sound." Just go over to your local big-box electronics chain and watch how so many people crank the bass all the way over when "auditioning" a new stereo. Could be Sony made a conscious marketing decision to emphasize the bass on the consumer mics and the new ones are in fact smoother. If you want bass emphasis in particular situations you could use equalization in post to shape the curve

In the venues you describe where you're recording I'd suggest you give careful thought to using directional mics such as cardioids or hypercardioids instead of omnis. You're going to be in an environment with potentially a lot of incidental background noise - glasses tinkling, conversations, music, etc, and more directional mics would help reduce its interference.

If you're going to be recording stereo, remember that a lot of stereo video ends up being viewed in mono. Stereo recording using omnis is done with spaced arrays where the stereo sound field is created by the arrival time differences, ie phase differences, of the sound wave at the two mics. This is fine in stereo but when you collapse the two channels together to make a mono signal, those phase differences can cause some real problems as sounds reinforce and cancel each other. OTOH, coincident mic techniques such as the X-Y and M-S techniques rely on intensity differences and use directional mics with their diaphrams placed as close together as possible so phase differences are minimized. This is much more readily mixed down to mono without problems.

Regarding surround, re-read that Schoeps white paper. First, with the exception of a couple of examples where omnis are used to fill in low bass response, those various surround sound arrays are done with directional mics - cardioids, hypercardioids, or figure-8s - and not omnis. Also, you don't need to record 5 or 6 channels on locations for a 5.1 surround track. The LFE (the ".1" part) is usually created in post from FX plus low bass from the other tracks. You also don't need to record the centre channel either since it's a blend of the left and right fronts it too can be created in post. All you really need is 4 mics on 4 channels and in fact using the Double M-S technique all you need is 3 mics recording to 3 channels - a cardioid for the the front mid, that also doubles as the mono centre channel, a cardioid for the mid rear, and a figure-8 in between that serves as the side channels for both front and rear.

Seems to me that you need 2 omnis, 2 cardioids and 2 hypercardioids to do the various things you want. If it were me, I'd add a figure-8 to the kit as well.
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Old March 25th, 2006, 10:50 AM   #3
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Hi,

I cannot thank you enough for that reply.

I spent most of the night and the whole day today testing with the F112's (all six of them) and I think that you are quite right - they are indeed a more accurate and uncoloured representation of the actual sound (although they may not be suited for my intended purposes).

You will notice that I edited my original message as I felt that it was unfair to trash a Sony product without giving it a real chance - I was just so frustrated and tired in the early hours of this morning. It really does seem that the F112's are great mics so sorry for anyone that read my original message - I was wrong.

There is a possibility that I can get a hold of a Sony F-740/9X on Monday to test and see how this shapes up against the F112's (although I am not really going to be comparing apples with apples).

Anyway - if the truth be told - these F112's for interviews and speeches and the like are just perfect - exactly what they are designed for.

I'm thinking that what might happen is that I hang on to one or two of them for interviews and the like and get some F-740/9X's for general recording and to try out my 5.1 OCT recording.

Anyway - thanks again for the reply - much appreciated.

Regards,

Dale.
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Old March 25th, 2006, 11:06 AM   #4
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Actually - on a lighter note - I know about the mixture of mics that Schoeps recommends for the OCT setup - but I had already ordered the F112's.

I have a disease called 'Sonylitis' - if Sony makes it - I have to have it!

Believe you me - this disease really is 'like no other'!

Regards,

Dale.
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Old March 25th, 2006, 12:49 PM   #5
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Quote:
Originally Posted by Dale Paterson
Actually - on a lighter note - I know about the mixture of mics that Schoeps recommends for the OCT setup - but I had already ordered the F112's.

I have a disease called 'Sonylitis' - if Sony makes it - I have to have it!

Believe you me - this disease really is 'like no other'!

Regards,

Dale.
Except that Schoeps recommends those mics for a reason - on each channel being recorded you need to emphasize the sounds coming from one general direction over those coming from other directions and omni mics don't do that. That's what omni means - equally sensitive in all directions <grin>. You need to have a directional pickup pattern so you can aim the mics and omnis pick up in a round, balloon-shaped pattern with the mic in the centre. Also, the F112 is a dynamic mic designed as a hand-held mic for news standups and interviews, positioned within a vfew inches of the speaker. I would expect it to be less satisfactory for recording music compared to small-diaphram condenser mics.
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Old March 26th, 2006, 02:56 AM   #6
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While we are on the subject I would just like to bounce something else off you:

First, I know that 'Omni' is supposed to be equally sensitive in all directions but I can tell you that this is not strictly true (with the F112's anyway). When speaking off axis i.e. not facing the mic directly there is a definite drop in signal strength and it just sounds 'different'. Is that what you meant by '<grin>' i.e. 'supposed to be' but 'not really'?

Second, I was told not to have two of these mics close together as sound from one 'will cancel the other one out'. Being forever the optimist I put two of them side by side on a mic stand and made a speech and I can tell you that either I can't hear this 'cancelling' or I don't know what it would sound like if it was 'cancelling' but I got a fantastic stereo track with no problem at all.

If I'm not mistaken the effect that I should have / could have got is known as 'phasing' or 'phase cancellation'? What would it sound like if this was happening? This may sound like a supid question but the stereo sound that I got was phenomenal. Was I just lucky with my mic placement or what or is it because both tracks were being recorded seperately as mono using a mixer and then played back as stereo (although logic tells me that this should be no different than recording a straight stereo track at once using the camera for example).

Regards,

Dale.
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Old March 26th, 2006, 07:10 AM   #7
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Quote:
Originally Posted by Dale Paterson
While we are on the subject I would just like to bounce something else off you:

First, I know that 'Omni' is supposed to be equally sensitive in all directions but I can tell you that this is not strictly true (with the F112's anyway). When speaking off axis i.e. not facing the mic directly there is a definite drop in signal strength and it just sounds 'different'. Is that what you meant by '<grin>' i.e. 'supposed to be' but 'not really'?

Second, I was told not to have two of these mics close together as sound from one 'will cancel the other one out'. Being forever the optimist I put two of them side by side on a mic stand and made a speech and I can tell you that either I can't hear this 'cancelling' or I don't know what it would sound like if it was 'cancelling' but I got a fantastic stereo track with no problem at all.

If I'm not mistaken the effect that I should have / could have got is known as 'phasing' or 'phase cancellation'? What would it sound like if this was happening? This may sound like a supid question but the stereo sound that I got was phenomenal. Was I just lucky with my mic placement or what or is it because both tracks were being recorded seperately as mono using a mixer and then played back as stereo (although logic tells me that this should be no different than recording a straight stereo track at once using the camera for example).

Regards,

Dale.

The <grin> was because I was pretty sure you already knew what omni meant.

You recorded two mono channels, left and right, and this is exactly what a stereo recording is. Sounds like you inadvertently stumbled on a common stereo mic placement known as "A/B micing" where two omni's are used. They're more commonly placed spaced some distance apart, in proper A-B micing they are spaced about 3 feet or so. There's a closer together version of a spaced pair called ORTF where they're 10-12 inches apart but this is usually done with cardioids. For a point source like an individual speaker centred on the mic your arrangement is perfectly fine for stereo and there's no reason they can't be close together. For music, however, the wider spacing is needed to help localize the various sound sources in the stereo field. Listening in stereo you're not going to hear any phase issues with your arrangement.

Phase cancellation problems do not occur in the microphones during recording unless you're also mixing to mono at the same time. Instead it's going to be most pronounced when you mix the L and R stereo channels down into a single mono channel. This can occur either intentionally as a mono mix when you prepare your final soundtrack or as a centre channel mix when you set up a 5.1 soundtrack, or it can occur later in the distribution chain after the material leaves your hands. Though you might have provided a stereo track on your final video, broadcasters and cable operators may for their own reasons collapse that into a single mono track for broadcast or the receiver or cable box may do that when it arrives in the viewers home. If your video is going directly to home or corporate clients, remember that an awfully lot of the TVs and VCRs where your video will be played are mono. Even some "stereo" TVs are actually pseudo-stereo, with mono circuitry feeding two dinky speakers on either side of the cabinet. A stereo VCR might have stereo audio outputs on the back panel yet only provide mono audio if connected to the TV through the RF out and TV antenna connection. Even if everything stays in stereo all the way down the line, phasing issues can occur in the air during playback as the sounds mix it up between the speakers and the listeners ears. You can hear this yourself by playing back some music on your stereo or home theatre, then reverse the polarity of the feed wires on ONE of the speakers and listen to the same music over again. You should hear a distinct difference between the two. To hear an extreme example, load a mono track into your audio editor (if you don't have one, you can download a copy of Audacity for free) and duplicate it. Invert the phase on one of them, pan them both to the centre so they mix, and play them back. You should hear .... nothing, silence. Now slip one of them back and forth a tiny hair with respect to the other and listen. The weird sound you are likely to get is caused by phase interactions reinforciing and cancelling sounds selectively. All this is why what might be good techniques for recording music destined for CDs might be less good when recording audio for broadcast and film or video soundtracks, and vice versa. For example, the A-B placement discussed above is fine for stereo but doesn't collapse well into mono while coincident placement such an X-Y arrangement where directional mics are placed one over the other with their diaphrams spaced as closely as possible can be easily mixed to mono.
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Old March 26th, 2006, 03:57 PM   #8
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Thanks very much for the detailed reply - it is really much appreciated.

If you don't mind maybe you could comment on the following test that I did today and maybe just give me some feedback (I have already ordered a book as recommended by DSE on Surround Sound Techniques but it has not arrived yet).

Today I took 5 of the F112's and arranged them carefully according to the Shoeps document detailing the 'OCT Surround' setup (paragraph 2 if you have the document). I know that these are not the right mics for this test but thought I would give it a try anyway until I can arrange to test different mics tomorrow. Having said this I don't think that the use of different (correct) mics would affect your answers to my queries or your input.

Basically I recorded 5 mono tracks (using the Schoeps mic placement method above) and got someone to read some lines standing in front of the center mic.

All input levels on the mixer for each channel were set equally i.e the physical settings were equal on the mixer for each input i.e. all gain knobs and sliders were in the same position for each mic. In other words it was not the actual input levels that were matched.

As one would have expected the level of the center mic was quite high (normal), the front left and front right levels were slightly lower, and the rear left and rear right levels were CONSIDERABLY lower.

I'm not quite sure what terms to use but in edit I then panned each of the channels to their extreme i.e. 'center' mic input (track) was panned sort of 'hard center', 'front left' mic input (track) sort of 'hard front left' etc. etc. In other words when mixing I 'placed' or 'forced' each track to play back out of its associated channel not allowing any channel to 'mix' itself with another channel.

First - is this the correct way to pan 5 individual mono tracks for surround. I just assumed that by leaving each track 'playing' or 'balanced' from center this would not create a surround mix i.e. all you would have would be 5 mono tracks each playing out on all channels just with different levels and the ouput of all of these channels would then just be 'summed'?

Second - is the reason that the rear channels were ALMOST not audible because I had tried this with a person delivering a speech i.e. it was not music - so the persons voice (unless they were shouting) was barely audible to the rear mics (they were facing backward as in the Schoeps document). Could this also be because I tested in an acoustically 'dead' room i.e. thick carpets and drapery, etc. etc. so there would be very little reflection of sound off walls and ceiling etc. etc.

Third - given the above result i.e. low rear levels - would one normalize each individual track prior to panning (or alternatively ensure that the levels of each track were individually bumped up to equal levels on the mixer during recording) i.e. so that each of the 5 mono channels were 'forced' to the same levels prior to mixing or panning? I would think that this would be defeating the object would it not i.e. to me the idea of surround sound is to recreate the sound stage for the listener just like it was when originally recorded.

The very low rear levels are the reason that I said that using the 'correct' mics for this purpose would not affect your response i.e. even with rear facing cardiods there just was not enough audible or reflected sound to be recorded.

I was a little dissapointed with result i.e. because of the low rear levels I did not get that 'theatrical' sound or 'live ambience' that I was expecting so either I do not understand this surround sound thing at all or I'm partly on the right track but am missing something in the details or concept.

Sorry - I know there are a lot of questions above but I really would like to nail this down.

Regards,

Dale.
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Old March 26th, 2006, 04:06 PM   #9
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Hi Steve,

I just read your responses to my questions again (for the tenth time or so) and also would just like to clear something up from your first response:

You say that you do not even need to use 5 mics for surround recording.

Will the way I am trying to do it not result in a far more 'accurate' representation of the 'live' sound i.e. sort of 'pure 5.1 surround' as opposed to 'electronically recreated' surround?

Just need to know if I'm going overboard (as I tend to do).

Regards,

Dale.
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Old March 27th, 2006, 06:22 AM   #10
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You were talking about panning the mics to one place or another. I have to ask the obvious. How were you recording all these channels? Were you mixing them all down to a 2 channel stereo output or what? That's what you discussions about panning in the mixer sort of sound like you're doing. To record that mic arangment you're going to need a multi-track recorder or a laptop with a multichannel audio interface and recording software that can lay down all 5 channels at once as separate tracks.

With one speaker close to your mic array delivering lines to an empty room I wouldn't expect much to be on the rear channels, or much stereo on the front channels for that matter. After all, what is there to record except room tone and some reverberence? If someone ran into the back of the room and took a shot at the speaker, now THAT would give you something for the rear channel LOL!

You don't need 5 mics because you don't always need to record the centre channel separately - a stereo mic arrangement pointed forward and another pointed rearward, mixing the Left Front and Right Front to form the centre channel in post, is a way to do surround using 4 mics. You can also do it with 3 mics if you use the "double M-S" array with two cardioids, one facing front and the other rear as the "mids" and a single figure-8 serving as the side channel for both mids. The Front Mid (FM) by itself is the Centre channel, the FM+S is the Front Left channel, the FM-S is the Front Right, the RM+S is the Rear Left, and the RM-S is the Rear Right. If you really set on recording surround on location in a field production such as you're doing, this "MSM" arrangement seems to me to me to be a very practical approach, far less intrusive than other multi-mic arrays and less "fiddly" to set up.
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Old March 27th, 2006, 07:42 AM   #11
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Hi Steve,

Sorry - I did not say how I was actually recording the stuff.

I have an Alesis FireWire MultiMix 16 Mixer so each mic is assigned a channel on the mixer and each channel is then recorded seperately as a mono track with Sony Vegas.

I think I'll try to get someone to shoot the speaker - coming from the direction of the rear mics - I'll let you know how realistic the sound was! :)

As far as using 5 mics - you are right - it is quite a pain to set them up - and for most of my events it would not be possible. However - at the end of the year all of these events culminate in a grand gala type of event i.e. huge auditorium, lots of 'cavernous' space, natural reverb (all my favourite effects) etc. etc. and I would like to have this setup working and properly tested before then.

I was thinking about renting an empty hall somewhere and getting a budding band or two to do their thing and record using the 5 mics - I think that this would be a good test.

Regards,

Dale.
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Old March 27th, 2006, 10:39 AM   #12
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Quote:
Originally Posted by Dale Paterson
Hi Steve,

Sorry - I did not say how I was actually recording the stuff.

I have an Alesis FireWire MultiMix 16 Mixer so each mic is assigned a channel on the mixer and each channel is then recorded seperately as a mono track with Sony Vegas.

I think I'll try to get someone to shoot the speaker - coming from the direction of the rear mics - I'll let you know how realistic the sound was! :)

As far as using 5 mics - you are right - it is quite a pain to set them up - and for most of my events it would not be possible. However - at the end of the year all of these events culminate in a grand gala type of event i.e. huge auditorium, lots of 'cavernous' space, natural reverb (all my favourite effects) etc. etc. and I would like to have this setup working and properly tested before then.

I was thinking about renting an empty hall somewhere and getting a budding band or two to do their thing and record using the 5 mics - I think that this would be a good test.

Regards,

Dale.
How are you monitoring? I glanced at the Alesis manual and it sound like it only has a 2 track return from the computer. To hear your rear channels you'll need have more than that going to your speakers.

As I read your mixer's manual, each input strip acts as a direct out when you assign it to a channel to record in Vegas. The settings of the pan left and right would affect the track's position in the 2 track mix but as far as I can tell they don't have any affect on the direct outs when recording each channel through firewire. I suggest you experiment and see what happens to the signal in one channel recorded directly into vegas when you swing the pan from one side to the other
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Old March 28th, 2006, 12:13 AM   #13
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Hi Steve,

Listen - I really appreciate all of your input and advice and having this discussion with me - especially going to the trouble of having a look at the Alesis manual which I can only assume you had to download.

Thanks.

You are right - the stereo pan on the mixer has no effect on the direct outs to the workstation. You can monitor individual channels or inputs using headphones plugged directly into the mixer and soloing the channel you wish to monitor (or obviously you can monitor the stereo mix).

It works well though - I just need to sort out these mics.

I tried to source the Sony F-780/9X mics here (in South Africa) yesterday but apparantely the earliest I can get these mics from Sony is at the end of May and, according to Sony here, the rest of the series i.e. the F-710, F-720, and F-740 have been discontinued.

Unfortuantely this has become a far more pressing issue since yesterday.

I had a long talk to the client yesterday and suggested that we do the sound for these events as well - which they agreed to. The main reason for my suggestion is that at all of the previous events the sound guys rock up with their Shure mics, PA, and mixing desks and it has been a concern of mine that this is a duplication of equipment to start with and I can just see us eventually running into problems between our Sony UWP Series and the Shure systems i.e. interference. They always offer me a mix from the PA which I always decline - mainly because of the snap, crackle, pop, and hum coming out of their PA - but they don't perceive this as a problem!!!

In addition to the above - for the next event (which is next week Thursday) - there will be four guests sitting at a table and each of them has to have a mic - I can't picture eight mics on the table - one each for the public address and one each for the video!

Anyway - any input on my problems is always greatly appreciated.

Regards,

Dale.

Last edited by Dale Paterson; March 28th, 2006 at 04:26 AM.
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Old March 28th, 2006, 04:54 AM   #14
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Quote:
Originally Posted by Dale Paterson

....
In addition to the above - for the next event (which is next week Thursday) - there will be four guests sitting at a table and each of them has to have a mic - I can't picture eight mics on the table - one each for the public address and one each for the video!

Anyway - any input on my problems is always greatly appreciated.

Regards,

Dale.
You might investigate using a boundary mic placed in the centre of the table. You didn't say if the table was round or rectangular but one or two boundary mics might do it. Depends on whether there are table cloths, etc, as well of course.
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Old April 12th, 2006, 01:38 PM   #15
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Double MS

Steve,

I've been listening in on this conversation and have learned alot from your comments. Thanks.
Is there a diagram of a Double MS arrangement that you can point me toward? A complete arrangement from mic to recording device is what I am serching for.
I do alot of outdoor documentary work and would like to be able to find the simplest way of doing 5.1.
I use an XL2. Can I go directly to that? Or should I use a separate audio recorder? If so which one would you recommend?

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