Topic: High Frequencies In Outdoor Recordings

[chris319]

I recently recorded a string ensemble in an outdoor venue. I tried eight different mics (I was shooting out mics that day). For some reason, all the recordings sound like they have the highs sucked right out of them. They sound wooden. They sound rolled off at 8 kHz, kind of like AM radio. I was seated in the front row, about eight to ten feet behind the conductor, with the mics about waist height (the height of an unextended floor stand).

The mics were:

CAD e70, omni capsule
MXL 991 with capacitor mod, omni capsule
MXL 991 unmodified, omni capsule
Studio Projects B-1
Heil Sound PR40
E-V RE27
E-V RE55
E-V 655C

Here is a clip from the Studio Projects B-1 recording, one of the least worst:

http://www.miclisteningroom.org/MSLMYSO/SP_B-1_short.wav

Why do my recordings sound so deficient in the highs? Is it the outdoor venue? The position of the mics? I have swept my system and I know it is flat to 20 kHz.

[boojum]

Waist height?  Sounds like a problem right there.  What was in front of the mics if anything.  Waist height is awfully low.  They should normally be 10 - 12' up and aimed into the group.  Could they have been facing backwards?

For a test mount one and walk all the way around it while the recorder is running to see how the sound changes as you move.

[raymonda]

I will take a listen and also look at the wave but if you were only recording strings I wouldn't expect much information beyong 8,000.

[raymonda]

The wave looks fine and overall it would have sounded fine but you have low frequency wind noise that causes a lot of problems. You should have used a wind screen or a more beefier one at least.

The primary frequency of strings do not extend that far. That is why you don't see much information up top.

Try your shoot out again but use screens or move it in doors.

[chris319]

For a test mount one and walk all the way around it while the recorder is running to see how the sound changes as you move.

You can't do that during a live performance in front of an audience

The wave looks fine and overall it would have sounded fine but you have low frequency wind noise that causes a lot of problems.

I know about the wind noise. Moving it indoors was DEFINITELY not an option. I'm talking about the sound of the instruments. Listen to the violins. There is no high-frequency detail.

[chris319]

if you're in the front row in a normal auditorium then you are below the orchestra

This was outdoors, not in an auditorium. The audience and musicians were on the same flat surface. Waist height means waist height to the conductor. Sorry, I should have been clearer.

the B1 is gonna drop high end detail over 13kHz or so by a function of being a large diaphragm mic

I did not know that. Now how do you explain the other seven mics? They don't sound any better. The B-1 was the only LDC among the eight. Must be the height.

[raymonda]

A violin's frequencies fall within 200 to 3.5khz. The table attached should help you out a bit on why there is little information above 6,000 hz on your recording.

Sure, getting your mics up about the instrument is the way to go. But what I hear as your primary problem is the accessive wind noise causing large low frequency rumble. Do you have full range speakers, or subs, that go down to 20 hz (-5dbs) or so. If not, it may explain why this is not obvious to you. But with woofers and speakers flapping like this it is hard for them to reproduce other frequencies reliably.

BTW, I wasn't suggesting that you ask the performers to move inside, but rather, try you rshoot out in at an indoor concert event.
Frequency Range of Vocals and Musical Instruments        Typical Sound Pressure Levels         

Vocal Woodwind Brass Strings Keyboards Percussion               

VOCAL   Approximate Frequency Range   Sound Pressure (N/m2)   Sound Pressure Level (dB)   Environment   Description
Soprano   250Hz - 1K   200   140   Military Aircraft Taking Off   Intolerable
Contralto   200Hz - 700Hz   63   130   Pneumatic Drill   Very Loud
Baritone   110Hz - 425Hz   20   120   Ships Engine Room   
Bass   80Hz - 350Hz   6.3   110   Factory   
WOODWIND   Top   6.3 X 10-1   90   Heavy Lorry (6m)   
Piccolo   630Hz - 5K   2 X 10-1   80   Busy Road (kerbside)   Loud
Flute   250Hz - 2.5K   2 X 10-2   60   Restaurant   Noisy
Oboe   250Hz - 1.5K   6.3 X 10-3   50   Conversational Speech   Quiet
Clarinet (B flat or A)   125Hz - 2K   2 X 10-3   40   Nightime (residential area)   
Clarinet (E flat)   200Hz - 2K   2  X 10-5   0   Normal Hearing Threshold   
Bass Clarinet   75Hz - 800Hz            
Basset Horn   90Hz - 1K   Reverberation Targets      
Cor Anglais   160Hz - 1K         
Bassoon   55Hz - 575Hz      Reverb time   Function
Double Bassoon   25Hz - 200Hz   Only Speech   0.6 - 1.2 secs   Lecture/Conference Halls
Soprano Saxophone   225Hz - 1K   Speakers (trained)   1.0 - 1.4 secs   Theatres
Alto Saxophone   125Hz - 900Hz   Reproduced Sound   0.8 - 1.2 secs   Cinemas
Tenor Saxophone   110Hz - 630Hz   Multi-purpose use   1.0 - 1.5 secs   Multi- purpose Halls
Baritone Saxophone   70Hz - 450Hz   Opera   1.0 - 1.6 secs   Opera Houses
Bass Saxophone   55Hz - 315Hz   Solo Instruments   1.2 - 1.6 secs   Recital Halls
BRASS   Top   Orchestras   1.6 - 2.2 secs   Concert Halls
Trumpet (C)   170Hz - 1K   Choirs/Organs   2.0 - 4.0 secs   Churches
Trumpet (F)   300Hz - 1K         
Alto Trombone   110Hz - 630Hz   Musical Range and Frequency       
Tenor Trombone   80Hz - 600Hz         
Bass Trombone   63Hz - 400Hz   (Piano Keyboard Equal Temperament)      
Tuba   45Hz - 375Hz         
Valve Horn   63Hz - 700Hz   Note   1   2   3   4   5   6   7   8
STRINGS   Top   A   28Hz   55Hz   110Hz   220Hz   440Hz   880Hz   1.760K   3.520K
Violin   200Hz - 3.5K   B   31Hz   62Hz   123Hz   247Hz   494Hz   987Hz   1.974K   3.949K
Viola   125Hz -1K   C   33Hz   65Hz   131Hz   262Hz   523Hz   1.47K   2.093K   4.186K
Cello   63Hz - 630Hz   D   37Hz   73Hz   147Hz   294Hz   587Hz   1.175K   2.350K   
Double Bass   40Hz - 200Hz   E   41Hz   82Hz   165Hz   330Hz   659Hz   1.318K   2.637K   
Guitar   80Hz - 630Hz   F   44Hz   87Hz   175Hz   349Hz   698Hz   1.397K   2.794K   
KEYBOARDS   Top   G   49Hz   98Hz   196Hz   392Hz   784Hz   1.568K   3.136K   
Piano   28Hz - 4.1K                           
Organ   20Hz - 7K                           
PERCUSSION   Top                           
Celeste   260Hz - 3.5K                           
Timpani   90Hz - 180Hz                           
Glockenspiel   63Hz - 180Hz                           
Xylophone   700Hz - 3.5K                           

[raymonda]

I love the comment about strings having no highs; try having three daughters learning violin and get back to me on that    Please consider the difference between fundamental tones and overtones--strings have a LOT of overtones).[/size]  So most of the highs are going over your head, especially if your mics are at waist level.

I believe I stated the primary frequency, I was not discussing overtones or upper harmonics, e.g 2nd, 3rd, 4th, or 5th, etc.......  Any bowed string instrument played by a novice or beginner can sound annoying. Relative to a paino a violin does not cover nearly rhe same range. Sorry, but that's just a fact.

[mfrench]

I regularly record a violin that aurally disappears at 14.5k, and is probably still making waves above where my cloth ears can hear them.

[raymonda]

I regularly record a violin that aurally disappears at 14.5k, and is probably still making waves above where my cloth ears can hear them.

Overtones my friend, overtones. It does not have any fundimentals up there. And, it should be relatively low in nature when copared to the primary note. 3,500 second harmonic is 7,000.... 3rd harmonic is 14,000 and 4th is 28,000.......etc...... If you are getting the db level as high as the fundimental note, there are some problems which will obscure the timbre.

[raymonda]

If you look at the frequency graph of he sample provided you will notice a 15-20 climb going down from 175 to 11hz. This is all wind noise muddling up things. Because of this, the conditions the recording was made under provides limited information regarding the mics and the shoot out.

[boojum]

Chris, pardon me for making a wild assumption.  I thought you might test the mics some other place or before the performance.  I guess I should have spelled that out for you.  Next time.

[raymonda]

raymonda, please, that table is really a joke.  Citing a fundamental frequency range of an instrument has 0% to do with the overtone series and therefore the high-frequency content of an instrument.  Many, many instruments have a LOUDER first overtone than fundamental.  Some of them have second, third, even fourth as strong as the fundamental.  The general rule of full-range recording is it tends to follow a "pink-noise" distribution with descending amplitude at increasing frequency.  There are many exceptions that rule, but the recording in question clearly shows a rolloff above 4kHz that exceeds the norm significantly.

Trust me, I have studied the overtone series of a violin.  To be blunt, you don't have any idea what you are talking about.  I can arrange a quick demonstration of many instruments here in my studio tonight that will prove this conclusively.


I would say that I have a bit of an idea of what I'm talking about and I stressed primary and fundimentals from the onset. I obviously have a good understanding of overtones and the effects it has on timbre and tone. Close mic'd in a studio will certainly provided a different frequency plot than far field, outdoors with an ensemble.

The decay of the note close mic creates very interesting changes. Pluck any string under a strobe an you can see the effects. I don't really see where we part thoughts, other than I think the recording is more effected by being recorded out doors with significant wind problems. Absolutely, having the mics up would be ideal. But with this recording it is secondary to the wind problem.

[raymonda]

Chris, pardon me for making a wild assumption.  I thought you might test the mics some other place or before the performance.  I guess I should have spelled that out for you.  Next time.

  Yes, there are always exceptions.

[mfrench]

this is a frequency scan of a short solo - that had some backing ensemble accompaniment - note the sharp spike at 20k+ :)

[chris319]

Not to pile on raymonda, but all you have to do is listen to the recording. It sounds like crap. It is unacceptable by any standard. In that regard, discussing the subject in terms of Hertz is not very meaningful.

[mfrench]

hz is of plenty of value.
Every one of those peaks above 10k is well above the suggested maximum high frequency that might be expected to be captured (paraphrase).
And every one of those peaks above 10k is a held sustained note, all of which have the possibility to be brought to far above the human hearing range.

[raymonda]

Not to pile on raymonda, but all you have to do is listen to the recording. It sounds like crap. It is unacceptable by any standard. In that regard, discussing the subject in terms of Hertz is not very meaningful.

I'm not sure how you are piling on. I agree that there were problems. I agreed from the onset and stated why I thought there was a major problem. However, we disagree as to what the primary problem is. Not that the other problems are not significant but rather predictable when considering it was recorded outside and far field, i.e., ambient (Omni), first row, head level.

Also, some of the wind actually increases the low end frequency by 30-40 dbs from 175-11hz, not just 15-20. Are folks really arguing that this is not a problem that would have a significant impact on the frequency plot and sound of the recording? Not to mention the challenge the electronics and speaker would have replicating this noise.

To me this so obvious that I find it amazing that others don't agree or at least acknowledge there is a problem and that my statement is correct.

My final comment, albeit, "stupid and ignorant" is, harmonics are not reinforced in open air as they are in a reverberant environment. A reverberant environment will/can cause peak and nodes depending on the demensions and reflectivity, or lack or reflectivity of the room. Thus, in open air, at a distance, you will not get the same frequency plot that you will get indoor. You usually get more fundimentals than harmonics.

Yeh, I'm sure I sound like I saying the world is flat but hey, I'm ignorant and my 30 years of recording and 40 years playing has taught me nothing but to be ignorant. 

[mfrench]

its violin torture to bring them outside anyway.

[raymonda]

Overtones my friend, overtones. It does not have any fundimentals up there. And, it should be relatively low in nature when copared to the primary note. 3,500 second harmonic is 7,000.... 3rd harmonic is 14,000 and 4th is 28,000.......etc...... If you are getting the db level as high as the fundimental note, there are some problems which will obscure the timbre.

WRONG.  An overtone louder than the fundamental could BE the timbre of the instrument.  Extremely common for example on piano in the bass register, especially for an upright.  And a 3.5kHz fundamental is very atypical on violin.  That would be one of the highest harmonics (playing technique terminology) that you'd hear from the soloist in a violin concerto, not quite what we have here.

Since you persist, a demonstration is pending.  Please note I don't play violin or piano, so the emphasis will be on frequency measurement, not performing skills.

I'm not sure what you are arguing. I think we agree. Many variables will effect the harmonics and harmonics effect the timbre and some harmonics can exceed the fundimental....very common in percussion........ So, where are we disagreeing.

Are you saying that there is no difference in the sustain of a note or the amplitude of the harmonics in a reverberant environment vs open air, far field recording. If so, then I guess we disagree. But I would assume your knowledge would agree with this.

Please see my other prvious last comment regarding my thoughts on this recording. 

[raymonda]

Anyway, before I post them, you have made another fundamental  error I didn't catch before:  the overtone series of a 3.5kHz fundamental is 7, 10.5, 14, 17.5, 21, 24.5, 28, etc., not merely 7, 14, 28, and further 2x.  That would be octaves, not all of the overtones.  Big difference in timbre, would you agree?[quote author=raymonda

True, those are octaves. In my attempt to simplfy I just mention them. But sometimes I quess it is important to be padantic. Thank you for pointing this out.

[raymonda]

Mshilarious,

Other than argue the fine points of my earlier sweeping generalization and make that the central theme of your next thesis, you have yet to comment on what I have indicated as the primary problem with this recording and its implecations. Do you agree or not?

[raymonda]

Then I quess that is where we part. Without the wind noise the recording would have had the typical sound of a two point, outdoor farfield recording. "Dry and lifeless" but acceptable to most novice recordest.

BTW, my generalization where not incorrect in the context of this recording, which I was relating to.

I stand by my statement that you do not often see much high frequency information recording this type of music outdoors. To me, looking at the wave, this is what I would expect and what I saw. Fundementals usually standout and dominate under these conditions. Harmonics get lost. (Please name the great orchestra recordings that were made outdoors. How about, none!!!! Oh yeh, that's a generalization, too.

The problem is not in the mic but rather the outdoors and the wind. I could listen to this recording without the wind problem, would it be great, no. It would capture the moment but not win a grammy for sound engineering. And for this recording i assume Chris was trying to capture the moment and not do a professional job.

If he is trying to do a professional job, then, as I stated, he would best be served with by using appropriate windscreens and or a high pass filter if screens alone won't do the job.

[raymonda]

Well how am I supposed to know what you are arguing when you keep changing it?

Your first comment:

Quote
I will take a listen and also look at the wave but if you were only recording strings I wouldn't expect much information beyong 8,000

Ray Clarify (under these conditions. I would have assumed that would have been understood. Of course it would be differant under other condition.)

And then:

Quote
The primary frequency of strings do not extend that far. That is why you don't see much information up top.

Ray Clarify (Under these condition overtones/harmonics will not be reinforced much, thus the fundemental will dominate)

and again:

Quote
A violin's frequencies fall within 200 to 3.5khz. The table attached should help you out a bit on why there is little information above 6,000 hz on your recording.

So your persistent original argument was that the violin has little information in the harmonic series above 6 to 8kHz.  Do you still maintain that position, or have you modified it?

Ray Clarify ( I never said that but rather was saying that under these conditions it wouldn't. Again, under ideal condition or other conditions the harmonics/overtones would extend but we were discussing this recording not recordings in your studio)

And then:

Quote
Relative to a paino a violin does not cover nearly rhe same range. Sorry, but that's just a fact.

It's true of the fundamental range but very untrue of the overtone series.

Ray Clarify (I was discussing fundimentals not overtones.)

and then:

Quote
If you are getting the db level as high as the fundimental note, there are some problems which will obscure the timbre.

Now an argument that an instrument's fundamental frequency must be louder than its overtones.  But wait, you modified that:

Quote
Many variables will effect the harmonics and harmonics effect the timbre and some harmonics can exceed the fundimental....very common in percussion........ So, where are we disagreeing.

Ray Clarify (Over simplification on my part. I should have said that differant environments will effect overtones in differant ways. If the environment alters the overtone dramtically it will create problems with the timbre. Try playing your violin in the shower.)

So I haven't the slightest clue what you actually think, but what you have posted is misleading because it contains very basic errors in understanding of how instruments generate sound.

Ray Clarify (It appears that you took my comments about this specific recording and made a sweeping generalization to include that it was absolute under all conditions. Now that is silly and explains your padantic responses. I would have assumed that you understood that I was commenting about this recording and the conditions it was made under, since that is what the topic is). 

Stay tuned for recordings . . .

Ray Clarify(I have hundreds and hundreds hours of my own recordings that I can reference and that I feel support my understanding of sound).

So, go to your church and record a violin from the first row and then go to the nearest playground and record the violin from 10 feet. If you think the frequency response and timbre is going to be the same well............ I think you will be surprised that there will be a difference.

[raymonda]

Now piano, a crap out of tune upright.  Sorry about that, the out-of-tuneness shows as a bit of warbling in the peaks, but I have young kids who bang on it, stand on it, color on it, etc., so tuning is not a real high priority.

Low G and high E, same fundamentals as the violin example, on the same chart.  Note the difference in the overtone series.  Which instrument has a higher possible fundamental (not shown)?  The piano (actually I managed a 3.5kHz fundamental playing a harmonic on violin, but it sounded really bad so I didn't record it.  I digress . . .)  Which instrument has more high-frequency content?  You tell me.

What are you arguing. That mic position will change the way the intruments timbre is percieved. (Well, of course) That your upright is crappy (or both)? I don't think you ever had an argument with me on either of these issues.

[raymonda]

(Well how am I supposed to know what you are arguing when you keep changing it?)

I wasn't arguing but rather stating my observations. My main statement was that 20-40 db wind noise is the most distubing problem with this recording, not the lack of overtones or reverb. Sure, you could EQ the wind out but he cure might be worse than the illness. And finally, the truncated high end is what I would expect under these conditions.

[chris319]

And for this recording i assume Chris was trying to capture the moment and not do a professional job.

Raymond, you're not even paying attention. Here is what I said in the O.P.:

I tried eight different mics (I was shooting out mics that day).

To put it in more explicit terms, I'm trying to figure out why my recordings, whether recorded indoors or out, lack sparkle and brilliance. They range from dull to sounding like sh*t. This was the first time I tried omnis and there were six of them.

If moving air currents are blowing the high frequencies away from the mic, fine, but I would like to see proof of the acoustical phenomenon behind it.

[chris319]

mshilarious -

Thank you very, very much for doing that. It is very revealing and I think it pinpoints my problem. I am even going to send your gifs to our conductor.

First recording was standing with a mic at seated waist level, about four feet away.  Second recording is sitting with the mic about 6' up, also four feet away.  That yields about a 6' difference in placement height with respect to the instrument.

I'm having a little trouble following your description. Let's try it another way. What would you estimate the angles were between the mic and the instrument? Let's use as our reference 0 degrees for pointing straight down, 90 degrees for pointing horizontally, and 180 degrees for pointing straight up.

[raymonda]

And for this recording i assume Chris was trying to capture the moment and not do a professional job.

Raymond, you're not even paying attention. Here is what I said in the O.P.:

I tried eight different mics (I was shooting out mics that day).

To put it in more explicit terms, I'm trying to figure out why my recordings, whether recorded indoors or out, lack sparkle and brilliance. They range from dull to sounding like sh*t. This was the first time I tried omnis and there were six of them.

If moving air currents are blowing the high frequencies away from the mic, fine, but I would like to see proof of the acoustical phenomenon behind it.

Chris,

I was paying attention. I guess you didn't make it clear whether you meant "do they lack sparkle under the condition you were recording" or "in comparison to a professional recording under ideal recording conditions". I took it to mean under the condition you were recording, e.g. far field, outdoors and windy conditions. And, I stated they are as I would have expected considering the conditions. Dry, no reverberent trails and lacking in overtones.

I'm sorry if my answer didn't appeal to the broader question.

But to answer the broader question, of course it doesn't sparkle, you were recording outdoors, far field in windy conditions, how did you expect it to sound.

And, as I have stated over and over, which apparently is not problematic for others, the biggest problem is the 20 to 40dbs of wind blasts coloring and distorting the low end and entire recording.

What does it matter if it doesn't sparkle, if you have all these problems in the low end. Damn, you can at least boast the high end 1.5 to 2db's @ around 10K to make it brighter but you can't correct the wreck that is going on down in the bottom.

[chris319]

I have SDC and dynamic mic recordings I can post. For your convenience here is the mic list again:

CAD e70, omni capsule
MXL 991 with capacitor mod, omni capsule
MXL 991 unmodified, omni capsule
Studio Projects B-1
Heil Sound PR40
E-V RE27
E-V RE55
E-V 655C

[raymonda]

Mshlarious,

According to your recordings, I stand corrected regarding my statement on the effect of outdoors and overtones reducing the high end in this recording. Apparently, it is more due with off axis position of the mic.

Thanks for your time, effort and correcting this mistake.

How about going back 20 feet and recording the violin and see how the overtones and fundimentals compare. Which most likely may replicate the recording situation.



 

[chris319]

mshilarious -

Could I ask you to post the spectral analysis plots for the low mic and high mic separately, rather than overlapping them (a total of four gifs)? Thanks.

[newplanet7]

Even though a lot of what is
displayed in this thread goes over my head,
I love these threads.
I can grasp a chunk of it at a time, so thanks
for your time fellas.
+t

[chris319]

Lemme do a rerecord and then I'll post the .wavs later today.

Well?

[boojum]

I am just dumber than a box of rocks so I cannot posit; I have to test.  Try the same mics indoors and see how they capture sound.  If they work fine, it is the venue when recording outside.  If not - which I doubt - it is some other thing.

One test is worth a thousand opinions.     

[chris319]

Again, I would like to know what acoustical phenomenon makes air such an effective low-pass filter when recording outdoors. Right now I am subscribing to the notion that it was mic position. I will have another shot at these strings on Monday night, but they will be indoors and my mics will be up high. Still, I am keeping in mind about the shortcomings of a LDC at high frequencies.

[boojum]

My guess is that the "acoustical phenomenon makes air such an effective low-pass filter when recording outdoors" is cockpit error.  If it were anything else it would be well known and the mic manufacturers or field users would have a ready fix for this.  The almost non-existent reporting of this problem makes me think it is what I have suggested.  Review your procedures.

If it is something else, as you believe, I sure hope you can clue us in on it.

[chris319]

If it is something else, as you believe, I sure hope you can clue us in on it.

You haven't been paying attention, either. The current theory is mic placement/angle relative to the instruments.

[Brian Skalinder]

You haven't been paying attention, either. The current theory is mic placement/angle relative to the instruments.

FWIW, that's my take, too.

Out of curiousity, what mic configurations were you using for omnis?  cardioids?

Edit to add:  How big / wide was the ensemble?  Proximity to lower frequency instruments may have contributed to their more dominant sound in the recording.  DSatz addresses "too close", including a nifty napkin diagram:  http://taperssection.com/index.php?topic=100121.msg1333662#msg1333662

[chris319]

The mics were:

CAD e70, SDC, omni capsule
MXL 991 with capacitor mod, SDC, omni capsule
MXL 991 unmodified, SDC, omni capsule
Studio Projects B-1 - LDC cardioid
Heil Sound PR40 - dynamic cardioid
E-V RE27 - dynamic cardioid
E-V RE55 - dynamic omni
E-V 655C - dynamic omni

One mic at a time, outdoors, waist-height to a standing person, front row on the same level as the ensemble, mono, pointing directly at the ensemble with the diaphragms perpendicular to the ground. As you can hear, I was just a little bit closer to the bass fiddle than to the rest of the strings.

The clip I posted is the Studio Projects B-1

[mfrench]

could it be that you're using tools better suited for near-field, in a diffuse field circumstance?
I don't want to sound like a mic snob, but, none of the mentioned mics stand out to me as being really good in the diffuse field.

[Gutbucket]

could it be that you're using tools better suited for near-field, in a diffuse field circumstance?
I don't want to sound like a mic snob, but, none of the mentioned mics stand out to me as being really good in the diffuse field.

I'm not familiar with those microphones (and haven't listened to the recording sample), but my thoughts are similar.  I suggest trying some mics with more of a diffuse field eq high end boost. If your recording is clean enough to support it you can also eq an appropriate boost after the fact.   Last night I recorded several chamber ensembles and a string quartet from audience height, 15' back (just a couple feet above stage height) with very nice results and plenty of harmonics.. granted that was indoors.  I did dial in about 1db of treble boost when I listened back later at home.

[edited for clarity and miss spelin']

[chris319]

The question is not how to rehabilitate the clip you heard. The question is why eight mics all have HF rolloff. The consensus is that the mics were physically too low and being outdoors, there was nothing to reflect the harmonics.

I suggest trying some mics with more of a diffuse field eq high end boost.

Look at the freq resp curve for the Heil PR40, one of the mics on the list. If that doesn't have HF boost I don't know what does. The PR40 was actually the most promising sounding of the bunch.

[mfrench]

I'll call malarky on being too low.
I can't recall all the times I've blown off concensus with very satisfying results.
One of my last recordings of a chamber orchestra  that I record (from last years seasons last performance), had my main pair at ~3'; also with a spaced omni pair taped to the side of a pair stage monitors less than 6" off the stage floor (monitors were muted - acoustic performance). They were spaced 5' and ~6" high off the stage floor (maybe 4"?), and set up as an experiment (control and test recordings). Great results, both pair.

[Gutbucket]

The consensus is that the mics were physically too low and being outdoors, there was nothing to reflect the harmonics.

I really doubt that those harmonics are being significantly reinforced by reflections indoors, most of the airy top is going to be dissipated before it even gets to a ceiling or wall boundary and then absorbed once it does.  The reflections off those boundaries will pretty much contain all frequencies except the topmost. 

I regularly record classical quartet type music with mics in the first audience row at or just above stage height.  The mics I most often use are sdc condensers with about a 3db boost up top that extends from somewhere below 7khz to above 20khz.  I may dial in a few more db at times to taste.

I also record plenty of fiddle heavy bluegrass and americana music outdoors from instrument height or below and it's not the top end that goes missing compared to indoors, it's the midrange and bass range early reflections and ambience.

I suggest trying some mics with more of a diffuse field eq high end boost.

Look at the freq resp curve for the Heil PR40, one of the mics on the list. If that doesn't have HF boost I don't know what does. The PR40 was actually the most promising sounding of the bunch.

 

Go where your ears are pointing you.  Try out some small diaphragm condensers with a top end rise if you can.  My experience is with Mike on the height thing being marlarky.

[mfrench]

I don't want to read all the pages again - so bear with this if its already been addressed - I do not see it addressed in your OP (which I did reread):
How were you rigged for wind protection?

[chris319]

Many of the mics listed have rising responses/HF lift, especially the PR40.

If not height then what? Wind would account for LF rumble but not for the loss of HF.

Here is the Heil Sound PR40 dynamic cardioid which has quite a rising response. It was the most promising sounding one of all. This clip is unequalized:

http://www.miclisteningroom.org/MSLMYSO/Heil_PR40_NR.wav

[mfrench]

Wind phasing could easily sweep frequencies. It happens all the time with strongly driven (strongly amplified) PA recordings,... to blow an acoustic impulse around would be easy.
I'd blame it on the Night Winds.

But more seriously, what was your wind protection arrangement?
OEM foams, upgraded thick foams, DeadRats, zeppelins??

[chris319]

Wind phasing could easily sweep frequencies. It happens all the time with strongly driven (strongly amplified) PA recordings,... to blow an acoustic impulse around would be easy.

Sounds plausible.

But more seriously, what was your wind protection arrangement?
OEM foams, upgraded thick foams, DeadRats, zeppelins??

None, and intentionally so. Eight different mics being compared. Remember, the intent was to compare the various mics. I didn't want windscreens, etc. altering the sound of the mics.

[boojum]

So far all we have us guessing.  Can you reproduce the effects?  Have you tried recording with this setup elsewhere?  This is a fine thread for theories but theories have not fixed the problem.   ;o)  Doing will fix the problem.  Try something different.   We all know what you have done is not working.   

[chris319]

I will be recording them again this very evening, but indoors. This time the mics will be up high.

[Gutbucket]

Quick example of low mic position on a string quartet recorded last night is attached, warts and all*

Microphones were positioned in the front row, ~15 feet from quartet, height was about even with the performer's shoes.  The 1st file marked 2009-10-11 sample (LR 4060).mp3 is the Left/Right stereo pair. Also attached is a second file which is the Center/Back pair recorded simultaneously marked 2009-10-11 sample (CB 4060).mp3.

*untouched raw recorded files: no eq is applied (L/R could use a slight presence bump and some top end air boost as the mics are slightly muffled by fabric over them, the Center mic even more so), levels are low, guy falling asleep to the left croaks audibly and the girl behind squeaks her seat.. yet they do it at the start of this clip so perfectly in time with the slight pauses in the music that I find it rather humorous.  If you listen to both clips you'll hear both the grunt and squeak on the left in the L/R file and the grunt in the left (front channel) and squeak on the right (back channel) of the C/B file.    Yet for a less than perfect recording at ankle level though fabric, the L/R pair sounds relatively balanced frequency wise I think.

[chris319]

Just got back from rehearsal which was held indoors. Mics were positioned immedately to the left of, and approximately two feet behind conductor at a height of approximately 6 1/2 to 7 feet. It made all the difference in the world! The high registers of the violins come in loud and clear. The only thing to deal with now is a slight hum from a fluorescent light fixture.

Back to editing.

[Gutbucket]

Sweet.  Now you just need get them to only play in the key of B and tune to that 60hz pitch. 

[chris319]

Disappointingly, the PR40 seems to have a shielding problem. They paint the thing with non-conductive paint and there is no electrical continuity between the wire mesh and ground. I hold it up to a light dimmer and I hear buzz, but the buzz is not audible to the ear. I must add, however, that I did a Joly-inspired modification by removing the inner layer of wire mesh which made an audible improvement in clarity. Still, I don't see how the grille was electrically bonded to ground.

I have a pair of AKG Perception 150s which sounded nice and sweet.

The conductor also discovered that she has a tone-deaf violinist (these are high school kids)! Oh my. She's going to have a talk with him.

[raymonda]

Chris,

If I'm understanding you, try scraping away the paint where the mesh and the body meet and soldering them together. The body should be grounded and that should solve your grounding problem.

Ray

[chris319]

If I'm understanding you, try scraping away the paint where the mesh and the body meet and soldering them together. The body should be grounded and that should solve your grounding problem.

There are two pieces of mesh: one on the end and one which goes around the inside of the cylinder. It is impossible to test the grounding through the non-conductive paint. I was going to bond the end mesh to the cylindrical mesh and then bond them both to a point inside the mic body. This will require a considerable amount of paint scraping.

[chris319]

mshilarious -

Did you ever re-record those violin samples?