Topic: Acoustic Recording Techniques

[Thelonious]

^Absolutely. Travelling right now and my personal hotspot seems inadequate for we transfer but will upload and share a fresh link on Friday when back on wifi…

[Thelonious]

Here is a fresh link to the big band file as requested. It should be good for 3 days. I will investigate an alternative to WT over the next couple of weeks as I saw a good thread with options.

https://we.tl/t-1GiantHcme

I also added a file from two nights later (Pastor T) as this was an all acoustic show, no PA whatsoever, in a tiny venue. Trumpet, sax, drums bass and guitar. For this one I hadn't arranged in advance and used CSHEB (DPA4060) into my R07. I mounted the mics on my glasses at my temple to use my head as a baffle. I was very happy with the outcome for such a simple set up. Very immersive image on headphones. I have added a picture to give a sense of the band/room. Note my feet in the foreground of one of the pics for a sense of my location.

[Gutbucket]

^ Love that.

Thanks for the link.  Will grab it this weekend.

[Gutbucket]

^ Enjoyed them both - sounded like I was sitting there.  Love recording music that doesn't need PA amplification.  So much more real when hearing the sound generated directly from the instruments themselves.  Makes getting a "good and real sounding" recording easier in a few ways as long as we can position the rig in the right location, which becomes even more important than when most of the content is through the PA

[Thelonious]

Thank you for the feedback on the previous recording.

I have the opportunity to record this same band (Ed Lister Group, not the Big Band) this Friday at the same venue. The only difference in instruments will that there will also be a keyboard which I am assuming will be amplified directly as there was nothing going through a PA at the previous show other than a SM58 for stage announcements.

My last recording was from the front row, in a large padded chair that went up above my head height drastically reducing the audience from directly behind me. The only crowd noise I had was from the other side of the room parallel to the stage from my seating position, which was only noticeable during the quiet passages.

In case you are interested as a frame of reference, and didn't hear those samples, please find 2 tracks below. These are different tracks than shared last time but the recording.

https://samply.app/p/Ga5WbtzNargjM4rqsvTD

I believe it is possible to scroll down and stream lossless but not sure as this is my first samply share. It is definitely possible to download them lossless.

I have gotten permission in advance to record on Friday and am looking to take my recording up a level.

What I liked about my previous recording was:

• Very good sense of immersion and soundstage with headphones (in particular the audience behind me vs. the band in front and all instruments seemed to be in the "correct" placement relative to my experience at the show
  Solid bass extension, mix was a little bass light at the show, and overall tonality. I do listen with a bass boost on certain headphones to fill in the bass and midrange a bit which I find sits beneath the highs with the 4060s with (small) grills.

What I'm hoping to improve with the recording this week is:
More full lower midrange
Increased direct to reverberant (and audience) sound
Better imaging on stereo speakers. I recognize/expect this will come at the expense of the headphone imaging.

I have reviewed the on stage thread again and would like to take my first step towards that style of recording by going to stage lip.

My current plan is to:
Set the (table top) mic stand just off stage such that the mic capsules themselves would be just over the stage lip ~8-12" above the stage surface, angled upwards (I will use the snare as an approximate height target). I may also be able to clamp to stage lip but not sure based on the lip itself being rounded.
My thinking is either a modified NOS or modified ORTF, dependent on the stereo angle I establish when I get there, with mk22s as I really like the sound of these up close. I tend to change the spacing slightly to optimize the SRA based on the fixed angle using an SRS mount for either of the two standard mic configurations.

I am not planning on adding additional mics this time as I want to be able to mount this all on a single stand, F3 clamped to the stand's base, so I can move it into and out of position before/between sets. This is a tiny space and cramped stage and I am very conscious not be in the musician's, or audience's, way. It is my goal, however, to add DPA 4060s mounted to the stage once the boundaries I ordered arrive in ~1-2 months. At that point I would switch the centre mics to hypers in X/Y but, again, that's next time out.

I will also probably record with the binauralish configuration with my 4060s and R07, as used last time, to have the option for a headphone mix should I have the same seating opportunity again and to mitigate risk (drums overloading analog inputs, though I suspect this is unlikely given the nature of the gig).

I have two questions that I am hoping to get perspective on.
1) Is there a minimum distance from the stage I need these capsules to be located to avoid any issues with reflection and
2) Are there any other considerations that could significantly influence the success of my approach that I may not have thought of here.

Thank you as always for any advice.

[Gutbucket]

1) Is there a minimum distance from the stage I need these capsules to be located to avoid any issues with reflection and

Not really.  The difference in path length between the direct line from source to microphone verses a secondary path of a strong reflection off the floor surface arriving momentarily later can manifest as a timbral shift, due to the first notch of the comb-filtering that occurs between the two shift shifting in frequency as the height is changed, but that's unlikely to be noticed as such unless listening while actively moving the microphone.  If you get a chance, play around with height while monitoring on headphones prior to starting recording, or call out height while actively changing it while recording soundcheck or whatever so that you'll be able to associate any change in sound with the change in height while listening later.  Decreasing or increasing height will shift the first cancelation notch up or down in frequency and may land somewhere within the low mid region.  Same applies to the spacing between two omnis as well as their distance away from a reflective surface.  That timbral shift is much more perceptually apparent when moving the mics while listening.  With the mics fixed in position the response remains constant and is not likely to be noticed.

The only distance at which there is no pathlength difference between the direct sound arrival and a reflection off a surface is with the microphone mounted right up against the surface itself.  At all other heights the paths are somewhat different lengths and will interact to various degrees causing some shift in timbre.  That's not necessarily a bad thing if it works to advantage.

I generally like my on-stage mics positioned low.  Directional mics placed low and angled upward toward the sources reduces pickup of the reflection somewhat.  You can place the 4060s directly on the stage surface without using the boundary mounts if you like, just make sure they won't get stepped upon.  I've sort of stuck them down in a crack between floor boards for trample protection a few times.  Some stuff does need the mics up higher just to get them closer to the source. But with standing musicians playing loud horns you may achieve a better balance of them and the less loud instruments when the mics are low to the stage.

Unlike a studio recording, as concert tapers we typically don't get the chance to play around with these setup tweaking subtleties since we usually need to just get setup and roll without the ability to make careful listening tests and adjust things based on what we hear.


2) Are there any other considerations that could significantly influence the success of my approach that I may not have thought of here.

We may have talked about this, but aim for a clean line of sight to the mics from instruments that are featured, or play in a more staccato way and thus do best when cleanly articulated- drums, percussion, vocals..  More legato instruments such as the horns wont won't suffer as much from a higher ratio of reverberant sound.  Sometimes its more about what instrumentation will be best translated as sounding "out in front" verses playing a more supporting roll.  Piano and drums can be that way, sometimes they need to be clear and upfront, other times its okay for them to be more buried in back in a supporting role.


What I'm hoping to improve with the recording this week is:
More full lower midrange
Increased direct to reverberant (and audience) sound
Better imaging on stereo speakers. I recognize/expect this will come at the expense of the headphone imaging.

Lower midrange- Influenced primarily by mic choice, mic placement, EQ.
Increased ratio of direct sound to reverberant pickup- Get the mics closer, Use a more directional mic pattern angled toward the source, Use things like that chair back as a baffle to favor sound arrival from the desired source. (Note- playback over headphones can support a somewhat higher level of reverberance than playback over speakers)
Better imaging on stereo speakers- Try a bit more spacing or angle between mics than whatever is optimal for headphones.  Playback over speakers involves some crosstalk between channels occurring in the space between the speakers and your head (each ear hear both speakers) which isn't present in headphone listening where each ear hears only one channel. So reducing the stereo cross-talk in the recording by altering the mic configuration somewhat may optimize a bit more for speaker playback.  I find speaker playback is improved while headphone playback doesn't suffer when using dummy head recording techniques with mic spacings greater than typical ear spacing.   A coincident pair of X/Y hypercardioids in the center + a pair of wide spaced omnis will help provide good imaging over both speakers and headphones IME.

[Thelonious]

Thank you very much for the thoughtful and detailed response. In terms of takeaways for this week:
The height of the mics from the floor can impact timbre. As there isn't a sound check, for this week I'll focus on making sure that the mics are equidistant from the floor to ensure they sound similar. One of the things I am considering is angling the mics and one outcome could be that one mic is over the stage floor and the other is off stage, resulting in about an additional 8" in distance to the main floor. I will definitely try to avoid this and can experiment in the future with optimal height when able to manually adjust during a sound check or performance.

I will use the mk22s this week, positioned low and angled up as they help me to achieve both the better overall frequency response (the mics themselves) and the distance to the music vs. audience and directionality should improve my direct  sound to audience ratio.

I am going to wait for the boundary mounts before putting the 4060s on stage. The stage is small and this week there will be another person on it (with a keyboard) and I am concerned about them being stepped on in the locations that I would like to use them. That said, I will have the boundary mounts and my hypers ready for a recording in the next couple of months and can graduate to that. It also allows me to run the 4060s binaural on Friday as a backup recording in case I run into a challenge with the main pair.

I should be good for direct line of sight to the sources, except the horns where you mention it may be least important. The drums being stage left will have a mic pointed just to their left and the amps are positioned around the outside of the stage so line of sight should be ideal for those sources. What I am learning is that, unlike recording from a PA, with acoustic sources it's more difficult to keep that line of sight as people move around the stage etc. whereas, with a PA, you can just get your mics up high to avoid any obstructions.

Thank you again for the advice, I will report back with results.

[Gutbucket]

Don't worry about height too much. Mic height is most important with regard to pickup of nearby audience members, and how close and on-axis or not the mics are to the sources. Place the mics where you want them but not where they will be in the way, managing pickup of nearby audience, respecting sight-lines. The effect on response from reflections off the floor is likely to be subtle and secondary to all that, most likely heard on more steady state sounds, bass lines bass drum.  Mostly know that keeping them low to the stage surface can work nicely when the situation calls for it.

[morst]

Don't worry about height too much. Mic height is most important with regard to pickup of nearby audience members, and how close and on-axis or not the mics are to the sources. Place the mics where you want them but not where they will be in the way, managing pickup of nearby audience, respecting sight-lines. The effect on response from reflections off the floor is likely to be subtle and secondary to all that, most likely heard on more steady state sounds, bass lines bass drum.  Mostly know that keeping them low to the stage surface can work nicely when the situation calls for it.

Remember, people are water bags which absorb sound.
Nearby reflections will be sucked up by their flesh and clothing, at the cost of the noises they make!

[Gutbucket]

Remember, people are water bags which absorb sound.
Nearby reflections will be sucked up by their flesh and clothing, at the cost of the noises they make!

A useful new acoustics measurement index!  AAE = The ratio of an Audience's sound Absorption / sound Emission.  Colloquially known as the Fonz index. "Ayyy"

"Hey, keep it down over there!" can now be used in reference to an unruly audience member's effect on the AAE index.

[grawk]

I've heard there are party favors that help that ratio quite a bit.

[rocksuitcase]

Don't worry about height too much. Mic height is most important with regard to pickup of nearby audience members, and how close and on-axis or not the mics are to the sources. Place the mics where you want them but not where they will be in the way, managing pickup of nearby audience, respecting sight-lines. The effect on response from reflections off the floor is likely to be subtle and secondary to all that, most likely heard on more steady state sounds, bass lines bass drum.  Mostly know that keeping them low to the stage surface can work nicely when the situation calls for it.

Remember, people are water bags which absorb sound.
Nearby reflections will be sucked up by their flesh and clothing, at the cost of the noises they make!

You must have taken "physics of acoustics" from the same professor I did. This was his EXACT phraseology when starting the discussion about room acoustics and "physical dampening".
+T for water bags, as we all mostly are. 

[morst]

Remember, people are water bags which absorb sound.
Nearby reflections will be sucked up by their flesh and clothing, at the cost of the noises they make!

You must have taken "physics of acoustics" from the same professor I did. This was his EXACT phraseology when starting the discussion about room acoustics and "physical dampening".
+T for water bags, as we all mostly are. 

I learned it in the field... FoH / audio dept knowledge base...
 

[rocksuitcase]

Remember, people are water bags which absorb sound.
Nearby reflections will be sucked up by their flesh and clothing, at the cost of the noises they make!

You must have taken "physics of acoustics" from the same professor I did. This was his EXACT phraseology when starting the discussion about room acoustics and "physical dampening".
+T for water bags, as we all mostly are. 

I learned it in the field... FoH / audio dept knowledge base...
 

My great Uncle, Merchant Marine, would say: "We went to the same school together, the school of life". 
Rock On brother morst! 

[Thelonious]

I recorded the band on Friday using the advice here as a guide. I ended up running the following mics.
1) CMC122 @+/-55°, 24"
2) CMC641 @+/-45°, XY
3) DPA 4060 @24" taped to stage

My thinking is that this would give me the option to mix supers/open cards or super/omnis depending on the recording.

Unfortunately, the audience absorption factor is very low on stage, and the 4060 recording had an excess of treble which had an edge to it. Even after EQing the omni pair (~-5db above 2khz) there was still a quality to the sound I found "hard" for lack of a better term.

Luckily, I was very happy with the 22/41 mix. The only thing I would probably do differently, other than having the band set up with the drummer in the centre if I was formally recording, would be to raise the angle on the far right mk22 to bring the trumpet up in the mix as it moves around the right side of the stage. I don't think the music stand helped here either as it was often between the trumpet bell and the mics. Still, as GB pointed out, the horns work quite well with reverberant sound making this less of an issue than it would have been with guitar or drums for example.

I was really happy with the outcome overall. Direct to reverberant sound, music to audience ratio and soundstage were all greatly improved over my ~binaural set up. Obviously this came at the expense of set up time and work in post which, it appears, scales exponentially with the addition of mics. I had 3 distinct mixes I went back and forth on before selecting the one I thought sounded best overall.

The advice on pointing the XY at the level of the snare was super helpful and I think the drum sound anchors the recording quite well, even if the drums are slightly loud in the mix which seems kind of unavoidable on such a small stage.

I put a couple of samples up here if anyone is interested.

https://samply.app/p/FqcMuOjiLELXeu9AHMPo