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Classical String 4tet in crappy room
Old 25th May 2006
  #1
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pkautzsch's Avatar
 

Talking Classical String 4tet in crappy room

Since the good room we wanted to do it in was blocked, it's probably gonna happen in a really crappy room that normally is used for medical gymnastics...
the facts:
9ft high, 18ft wide, 18ft long (yeah, square....).
There are a few matresses (absorbers...) and a few mobile mirrors that can serve as diffusors.

I'm thinking about an overall ORTF with two Schoeps MK4 and some blanket behind it (Reflexion Filter would be nice in here - shame on me I dissed that thing in the past!), and KM184 about 2 ft away from each instrument. Probably use lots of the 184s plus some nice convolution reverb.

What would you think?
Old 25th May 2006
  #2
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mosrite's Avatar
 

In a crappy room using the plane of null that a figure of eight offers might be beneficial. You should probably also decide if you want to "fight" the room acoustics or make the best of it as this will probab;y affect your strategy in tackling the recording.
Old 25th May 2006
  #3
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Thanks for pointing out the different strategies Probably it's going to be a mix of fighting the worst of the bad acoustics and making the best of the unfightable rest.
And, of course, it's lo-budget. They're paying me, but no money for other stuff, and usually I record in appropriate rooms, cos that's the point of mobile recording, isn't it.
I'll try and improvise two sort-of-absorptive walls (matresses, blankets on mic stands) and the other two reflective / diffusive (w/ those movable mirrors and stuff). Have the musicians in the absorptive corner to avoid too early Early Reflections, and use cardioids pointing away from the reflective sides.
Maybe I'll do XY instead of ORTF for the "main" pair. I'm starting to get an idea about how it could work...
I'll put up some wavs when it's done.
Old 25th May 2006
  #4
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sedohr's Avatar
 

Quote:
Originally Posted by pkautzsch
Thanks for pointing out the different strategies Probably it's going to be a mix of fighting the worst of the bad acoustics and making the best of the unfightable rest.
And, of course, it's lo-budget. They're paying me, but no money for other stuff, and usually I record in appropriate rooms, cos that's the point of mobile recording, isn't it.
I'll try and improvise two sort-of-absorptive walls (matresses, blankets on mic stands) and the other two reflective / diffusive (w/ those movable mirrors and stuff). Have the musicians in the absorptive corner to avoid too early Early Reflections, and use cardioids pointing away from the reflective sides.
Maybe I'll do XY instead of ORTF for the "main" pair. I'm starting to get an idea about how it could work...
I'll put up some wavs when it's done.
are you recording classical music or pop ?

Kalli
Old 25th May 2006
  #5
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Classical. Bach, Haydn, Mozart, Schubert.

And Yes, I know I should use a good room. Yes, we did have a good room. And Fvck, this room was needed for another event which had priority.
Old 26th May 2006
  #6
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I think your plan will work well. I guess my first move would be to place the ORTF array somewhat lower than normal, maybe at standing head-level, to avoid hearing much of the room. If the ORTF doesn't sound good, then perhaps switch to spaced wide cardiods in straight A-B, at about 7 feet away from the front 2 instruments. This way you will get a good image to then enhance with your spot mics, without dealing with room sound.


JazzYoda
Old 26th May 2006
  #7
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Now this is interesting. I'd probably have done somewhat like the opposite of this: go high and point straight downwards...
In sort-of ear level I would probably end up right in the middle between floor and ceiling, but I'll try anyway, and get out of that center position.

Anybody done a pair of quasi-PZM (Mics lifted up on a stand or even taped to the ceiling, thus eliminating one reflexion surface)? If yes: what mics did you use?
Old 26th May 2006
  #8
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if you are using cardiod then the floor and ceiling are in the 90 degree off-axis null
Old 26th May 2006
  #9
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liuto's Avatar
 

I have used three Oktava MK012 omnis in a kind of DECCA tree lying in front of a chamber ensemble. I constructed some kind of open box to protect them from being stepped on. It sounded ok for a baroque opera documentation. There was some loss of high frequencies due to reflection effects but if I had used my diffuse field KM83s it would probably have been perfect but I did not bother to lie them on the floor . No problems also with structure borne noise.

Hermann
Old 26th May 2006
  #10
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Quote:
Originally Posted by liuto
I have used three Oktava MK012 omnis in a kind of DECCA tree lying in front of a chamber ensemble. I constructed some kind of open box to protect them from being stepped on. It sounded ok for a baroque opera documentation. There was some loss of high frequencies due to reflection effects but if I had used my diffuse field KM83s it would probably have been perfect but I did not bother to lie them on the floor . No problems also with structure borne noise.

Hermann

Try getting the DECCA tree higher, 2 metres or so should do. Those Oktavas usually have alot of high frequencies but the KM83s are better. Better still, get some Schoeps 222 or CM6, B&K, or Earthworks. The new M150 would be my mic of choice for a decca tree.
Old 26th May 2006
  #11
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Quote:
Originally Posted by JazzYoda
if you are using cardiod then the floor and ceiling are in the 90 degree off-axis null
Huh? Cardioids have only one null, and its not at 90deg, its at 180 and usually it points towards the audience in a main ortf pair.
Old 26th May 2006
  #12
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pkautzsch's Avatar
 

Yoda, you meant fig-8s, didn't you?
About the Tree: it's really difficult to get a three-mic Tree to sound good with four instruments, even in a good room. Close-miking every one will be definitely one half of the solution - so the other half will probably be some setup that is farther away than a Tree. I've been starting to tend to XY...
I still have time to try out the DIY "reflexion filter" I constructed this afternoon. It's not a lot of development, just some foam and maybe some pieces of wood taped to the back of that foam. 10 mins work...so it's worth a go.
Old 26th May 2006
  #13
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cardioid also has 90 degree rejection, just not as much as figure 8, The 180 off axis is a lobe like the figure 8 back lobe, out of phase, except it is greatly attenuated compared to figure 8. therefore the degree of rejection is much less than if both lobes were equal (bidirectional) or if they were not as different (hypercardioid)

Not wanting to either a. be an idiot(quite possible), or b. sound like one (which i was afraid i was), i did a test (one which i have performed before).

Not satisfied with the sound of directional microphones and not believing that a "true" cardiod pattern is possible, and especially upon reading other words to the effect, I performed a few tests.

First, to establish true phase relationship i auditioned a pair of matched mikes on figure 8, one facing front, one facing back, this established the "sound" of phase cancellation. This is a predicatable sound where the lower frequencies become cancelled out dramatically.

Next up, i switched to omni. On omni the microphones did not sound the same from the side as they did from their respective fronts, but the fronts were even.

Next up, I switched to cardioid. On cardioid, one would expect it to sound like a single omni. It doesn't. As you increase the gain to the "backward" mic, it begins to sound more and more like the phase cancelled pair of figure-8s, until it is strikingly similar, although the other side of the mic is now much much louder. Clearly those graphic representations of polar patterns are not showing this lobe.

On the other issue, of why an omni mic sounds like a figure 8 mic for high frequencies, I can only point to the directionality of sound waves as they gain frequency. Those teeny waves just don't cause much of a ripple in a membrane that is now showing them its profile instead of its face. But I can then also assume that no matter what pattern is selected on a dual-diaphragm condenser, it will behave this way, simply due to the capsule orientation.
Old 27th May 2006
  #14
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Everything has been dicscussed except 2 things-- the sound of the room and the mics available.

I had to record a quartet in a nasty room-- imagine an 80gal oil drum-- for a major lablel.

I wanted good imaging (eliminated omnis except with a Jecklin disc which I did not own at the time) and smooth sound in spite of the room.

Tried Royer sf12-- simply not enough transients and the imaging was too wide-- ended up with Schoeps tubes with MK21 caps.

AND good linear phase EQ and Altiverb-- both of which saved the day.

MORAL: if you must make a silk purse out of a sow's ear of a room, start with decent mics and use all the tricks!

Rich
Old 27th May 2006
  #15
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PS-- I would not get nearer than several meters to strings (even in a good room) with 184s. Preferably leave them at home.

Rich
Old 27th May 2006
  #16
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Quote:
9ft high, 18ft wide, 18ft long (yeah, square....)
Have you given any thought about the quartet's position in relation to the walls?

Position the group near the corner, but not "centered" in it (at what would be a 45 degree angle). Imagine them centered on the long side of a 3-4-5 triangle. In other words, at a 30 degree angle to one of the walls.

The room, although square, would be a rhombus in relation to the position of the group and your mics. I would use the mattresses to deaden the corner directly behind the group. Room reflections would smooth-out and be much less of a phase problem.

I would also suggest M/S mic'ing the quartet. It could give you some additional control during post.

Sounds like a tough one -- good luck!
Old 28th May 2006
  #17
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So I had them in somewhat cornerish, deadened the corner as good as was possible, had an MBHO cardioid for violins and viola and an MK4 for cello, plus a pair of MK21 overall, spaced a little more than 1ft, angled about +-10° (to keep the image stable and the reflective walls out).
Will post clips tomorrow.
Old 29th May 2006
  #18
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Here's a clip of Mozart KV 157, played by good hobby musicians and students (but no real professionals though).
A little Hi-Pass on "main" and vl/vla mics, a little TC Native Reverb.
Attached Files

sample_mozart.mp3 (4.02 MB, 441 views)

Old 30th May 2006
  #19
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The MP3 did the sound no favors-- a noticeable amount of HF artifacts.

To me it sounded like a non-standard setup with the cello and viola the opposite of the way a quartet usually sits.

That is also a compliment to the imaging, but it also is a way to say that to me it was too close. The group went from hard left to hard right-- fine for a large ensemble but a bit overly-stereo for only a quartet.

I was also hearing quite a bit of scratchiness-- the first sign that the mics are a little too close to strings.

And if you are going to add reverb I would suggest adding more so it sounds like they are actually in that acoustic. A bit more first reflection would help that.

Overall it sounds like the players should be very pleased!

Rich
Old 30th May 2006
  #20
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I found the Highs to be very unpleasant,"screechy" and overpowering, not enough mids and lows.. MBHOs are good for that, from what I know of them. why the High Pass? sounds like you took too much low out..

the spread was extreme, but I didnt notice that as much as the HF stuff.
Old 30th May 2006
  #21
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Roland's Avatar
Quote:
Originally Posted by pkautzsch
Since the good room we wanted to do it in was blocked, it's probably gonna happen in a really crappy room that normally is used for medical gymnastics...
the facts:
9ft high, 18ft wide, 18ft long (yeah, square....).
There are a few matresses (absorbers...) and a few mobile mirrors that can serve as diffusors.

I'm thinking about an overall ORTF with two Schoeps MK4 and some blanket behind it (Reflexion Filter would be nice in here - shame on me I dissed that thing in the past!), and KM184 about 2 ft away from each instrument. Probably use lots of the 184s plus some nice convolution reverb.

What would you think?

The thread seems to have drifted a bit, but on topic, I would first try and move the venue if at all possible. You are dealing with 4 musicians with "hand held" luggage, shouldn't be too much of a problem to find a better venue. If this is absolutely out of the question, you need to close mic and sort it out later. Again better if you can track all the instruments seperately. KM184's and Schoeps in this instance are capable of doing an adequate job.

Regards



Roland
Old 30th May 2006
  #22
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Just before someone tries and flames me, for clarity, when I state above tracking instruments seperately, I'm refering to one mic per player to individual track on recorder, NOT one player overdubbing at a time. You could try the ortf set-up as you described earlier in the thread, however I would still want each instrument spoted as a back-up.

Without a decent venue its always going to be a compromise, sa above will make the best of a bad job.

regards


Roland
Old 30th May 2006
  #23
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It's really interesting what mp3 does. The spot mics are panned 40%-15%-15%-40%, the main pair gives an even narrower image actually. On the WAV files, that is. Just listened to that mp3 file and found precisely what you said, sonare: a lot too wide.
I'm adding more reverb, and got the level of the spots down about 3 dB. It's good to have another few pairs of ears Thanks a lot!

Roland, I appreciate what you said about finding a better venue. We would have done that, had the musicians had the money or time. It's not easy to find good rooms for free in Germany on a Sunday morning when all churches have services. It was sort of worst case, but I feel it's not as bad as the room looked.
Old 30th May 2006
  #24
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Do you mind if I take the clip and run it through some processing and post it back in here?
Old 30th May 2006
  #25
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Yoda, try I'll definitely will have a good listen to what you make out of it and learn for the next time.
The improved version I made this morning will be the one to be released anyway since there simply isn't any more time and it's a promo CD for a medical organization to be given to donors at an event next week where the musicians play the music we recorded. Probably, nobody will actually really listen to it but only have it running as background noise...
Had it been for commercial release, we would never have done it in a sub-optimum room, and we would have had the money and the time to get an appropriate venue.
Old 30th May 2006
  #26
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Ok here's a try...

It was too many different processes to detail them in words so I took a screenshot. The room sample was the Esterhazy Haydn Hall
Attached Thumbnails
Classical String 4tet in crappy room-screen-grab-may-30-2006.jpg  
Attached Files

Mozartclip_processed_01.mp3 (2.02 MB, 413 views)

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