Recording Accessoiries

[Emmathom]

Hi Folks

I thought that a topic on the microphone and recording accessories that we make (or adapt in the case of purchases) could be interesting. We could share our "tips".
Most often we are led to make these accessories which cannot be found in stores or at prohibitive prices. In French (and rather in the cinema) we call all of these personal accessories with which we work and which belong to us "our jewelry".

I will start with a problem that I encountered during my last recording. The alto violin was quite close to the piano and the piano was bleeping into the violin track. (see photo). No need to ask the violinist to move: the musicians are used to their positions and are reluctant to change them. And the mic has to be quit far away from the violonist (60cm at least) because she wanted to be free to move her bow without risking hurting it on the mic (bows can coast hundred of euros and even much more).

So I thought of making a kind of "cap" which could reduce the bleed (while knowing that it would not eliminate it completely). But each dB gained is important.

So I started with a base made of a plastic binder that I cut so that it encompassed the microphone at 180°. In fact, 180° is not necessary and I reduced the curve.
I chose to use an aquarium filter to dampen the recorded sounds hitting this cap and which could bounce and create unwanted artifacts. These filters exist in different densities: I chose a very low density and therefore a rather airy and large mesh. I glued it with neopren on the plastic cap.
The cap is held on the microphone suspension by small document clips. You can see some picts below.

I haven't made audio tests for now but will do asap and let you know how much unwanted sound it can reduce.

 

[Emmathom]

Since I'm alone to do some tests, I will proceed so (see pict) :

Without cap :
- I will play some acoustic guitar in axis 60cm from mic
- I will then move off axis (by ~ 90°) but still 60cm from mic (as if another musician was playing aside)

And do the same with the cap, of course without changing a thing between the 4 recordings.

I will be able then to compare the bleed (in dB) with and without the cap in the 2 recordings off axis AND also how the cap may influence the sound in the axis mode.

 

[zamproject]

Hey

That's my personal thoughts... don't take it as absolute fact or discouragement for your try...

I don't think your panel assembly will work that well, too close from the mic (possible comb) and probably useless at mid to low freq. I suspect you won't have that much overall rejection (especially from a big omnidirectional instrument like piano), but filtered bleed that may give you an even worst piano sound in that mic.

Don't you have mobile acoustic panel to place behind the alto ? seem there is room , and alto player already turn the back to the piano so no constant eyes contact required.

In situation where there is no placement option and obvious bleed unavoidable, I'll try to make the bleed nice, by mic choice and orientation according to polar pattern and -natural- rejection.

 

[Emmathom]

Hey

That's my personal thoughts... don't take it as absolute fact or discouragement for your try...

I don't think your panel assembly will work that well, too close from the mic (possible comb) and probably useless at mid to low freq. I suspect you won't have that much overall rejection (especially from a big omnidirectional instrument like piano), but filtered bleed that may give you an even worst piano sound in that mic.

Don't you have mobile acoustic panel to place behind the alto ? seem there is room , and alto player already turn the back to the piano so no constant eyes contact required.

In situation where there is no placement option and obvious bleed unavoidable, I'll try to make the bleed nice, by mic choice and orientation according to polar pattern and -natural- rejection.

Hi @zamproject ! Thank you. Your observations are wise and certainly true. I believe your are used to these situations... You're right saying that the piano is loud and omnidirectionnal and so I won't get a lot of rejection... That was impossible to put some screen on stage because I was shooting a vidéo clip. I also recorded live this orchestra with an audition, so no way to put an acoustic screen on stage, unfortunately.
About the filter comb I'll make some tests and post them. Once again the goal is to try to win a few dB's

 

[ubxf]

Could a piezo mic on the viola help adding a bit of direct sound in the mix ?

 

[Emmathom]

Could a piezo mic on the viola help adding a bit of direct sound in the mix ?

Or a dedicated miniature SDC on flexible, yes, but I do with what I own for the moment...

 

[Emmathom]

I think about posting an excerpt of the recording concerned : the main mix and the same part with the alto violin in solo, which means :
- we can ear the level of the instrument solo vs the whole mix level
- we can ear the bleeding in the mic
Will do that quickly...

 

[Emmathom]

Here we are...
The orchestra was composed by a piano, a violin, an alto violin and a cello.
Below an excerpt of the whole instruments together and one of the alto track in solo (in where we can ear qiet much bleeding of piano & lead violin).
In the same time, we must not forget that this recording is destined to be heard with all instruments in together ! If the balance is satisfying, then the result is ok...

Alto solo

All instruments

 

[zamproject]

Ho ! I don't get it was a concert recording...so nothing we can help afterward unfortunately.

Transparent panel are frequently used, which are good for audience and video capitations, but this add high reflective surfaces

I suppose you uses one or two ambient pair (whatever type) in addition to close mic ?
I'll probably use them as a first layer, assuming it's pro musician that have a good global balance.
Then open close mic if needed to add little precision...

Could a piezo mic on the viola help adding a bit of direct sound in the mix ?

Don't know where is the technology around piezo today, but in my mind that's not the sound I'll expect to have from a
-classical- performance

 

[Emmathom]

I suppose you uses one or two ambient pair (whatever type) in addition to close mic ?
I'll probably use them as a first layer, assuming it's pro musician that have a good global balance.
Then open close mic if needed to add little precision...

Unfortunately I should have done so (and I regret). I hadn't enough mics to add an ambiance couple... but effectively a good ORTF pair in front of the orchestra would maybe have provided better results.
I did so on a cello quartet with one SDC omni pair + a LDC M/S + an SDC ORTF (for choice) and I chose the omni pair (but the ORTF was very interesting too).
I should stick now to ambiance pairs as it's the most academic way to record classical music (any acoustic music in fact)

 

[zamproject]

Here we are...
The orchestra was composed by a piano, a violin, an alto violin and a cello.

Very informative !

In fact I don't find the bleed on alto mic that problematic ...considering the recording condition...
And to my ear the piano sound good on it (better than the violin but this one is less prominent)
I'm sure you'll find the proper balance to mix this recording, musician seem good, which is the most important part...
If this job is not for a very demanding classical label you'll be fine I suppose.

Unfortunately I should have done so (and I regret)

Lesson learned

At this point you should reverse your mind and look at the crosstalk/bleed as a chance !!!
To give you some space an the natural sound you miss without ambient mic.

By the way what is the name of the quintet ?

 

[Emmathom]

The quintet is composed by musicians which play here and there, with other musicians, in duo, trio, etc...

No it's not for a classical label but for my pleasure and to train myself. I began "outside recordings" 2 years ago in my region and since then "follow" the cello player in his different bands & recitals. He plays classical, baroque and sometimes eastern music, film music... so it's interesting & challenging since he never plays the same works twice.

I planned to set-up my pro Facebook page this winter to post my photo shootings, vidéo recordings and (of course) audio recordings and will add it to "my signature" here in diyaudio.

 

[Emmathom]

While waiting for me to record my guitars with the cap, I'm posting the solo tracks of the violin and cello to ear the level of bleed in these mics. You have already access to the full quartet track (not a quintet sorry I mixed up my mind) and the alto violin solo track...

Also a picture of the whole thing to visualize the placement of each one. The violin player has a difficult approch with micking and recording and she demands the mic to be far from her, even on top, or from behind > a kind of nightmare (but she's kind and plays well)

The problem with strings players is the bows. Their movements can be very large and they fear about their (expensive to very expensive) bows.

The piano mic is a Superlux S-502 ORTF (which I really like / coupling capsule caps - 680pF - have been replaced by polystyren-cooper caps). The cello mic is a DIY tube mic (based on 6AK5 / EF95 tube > I've posted on thread on it). The violin mic is a modified t.bone SC1100* (original capsule but completly diff. circuit > also a thread on it). The violin mic is a Warm Audio WA-84.

* the t.bone SC1100 capsules (got a pair) will be soon replaced by Arienne K47 flat

Cello solo

Violin solo

 

[ze marcelo]

Felicitations!!! even with some problems you managed to achieve a good result, in the end that's what matters.
As already said, I would have also tried a classic stereo pair like A/B, XY, ORTF to record the ambiance. If you don't have enough microphones for the instruments and the room you can opt to use just one microphone for this, in this case I think the DIY tube microphone will probably record very well. That's my two cents.

 

[Barry Hufker]

I don't mean the following to be critical. Please don't take it as such:
In my experience with classical music, unless there is some special reason to multi-mic a small ensemble, I suggest a simple pair (possibly with a spot mic). The spot mic might be for either the piano or the cello, to give them a little clarity, but only if absolutely needed.

A simple stereo pair is what ze marcelo recommended and I agree completely. Multi-mic'ing creates more problems than it's worth here. In my experience, a good, matched stereo pair of mics (personally I use spaced omnis) placed above the players will give you the sound and the balance you need. They shouldn't be too close. You may have to play with the height, as well as the front/back position, as you want to capture an even balance between the instruments with a "good sense of hall." Depending, a second stereo pair of some sort can be used to pick up the room and blended in as needed.

A spot mic might be used for the piano (although shouldn't be needed for "level," just for "presence."The level of the piano's contribution should be adjusted by placing the piano on the short stick or full stick, with the spot mic used if neither of those work. The pianist can play softer or louder. A large part depends upon the quintet's ability to balance themselves and spot mic'ing isn't going to save that, but it can help when carefully used.
The piano doesn't need to be "huge," just realistic in its size compared to the rest of the instruments.

If the cello needs a spot mic for "definition" or "clarity," it should not be the main contributor to its sound, but just slightly mixed in in case it gets lost in the mix. But you shouldn't really need it, and you most likely will not need a spot mic on two instruments (but I concede one never knows until the situation arises).

Acoustic instruments need room for the sound to bloom, so space is your friend. My thought is never to put up one mic more than you need, but also never put up fewer.