Topic: Acoustic Concert Recording

[celtic]

Looking for some advice on acoustic concert recording. The gear I use is a Sony M10 -sound professionals key fob battery box SP-SPSB-20 - Church Audio CA14 Cards Mics. I plan to record a few acoustic concerts in a 1000 capacity venue. I recently recorded acoustic concert at same venue with same equipment and there is quite a bit of noise on the recording. The level was set at 5.5, Mic in , sensitivity switch set to LOW, Low cut OFF / Limiter OFF etc. Anybody use similar gear and what recording level do you set the recorder to get the best results for acoustic concerts.
Also is there anyway to remove the noise from a recording without ruining the recording?

[voltronic]

You might get more traction on this post on the Acoustic Recording Techniques thread.

I used to have almost the same gear when I was starting out, and your settings sound correct on the M10.

When you say 'acoustic concert recording' are you referring to a performance where there is no PA amplification, and you are out in the audience? If so, I'm sorry to tell you that you will never get decent results unless you're within the first few rows, very close to the performers. I made some very nice acoustic recordings with your gear, but I was set right at the stage. If you go any significant distance back, you're easily going to be outside the 'critical distance', meaning you are picking up more diffuse reflected sound than you are direct sound from the voices and instruments. This also means the ratio of music to room noise is going to be poor. The self-noise of the M10 isn't terrible, and Church doesn't publish specs, but you're also going to be up against the noise floor of your recording chain when recording acoustic music at a large distance.

iZotope RX is amazing for noise reduction, but it's not going to save you. You need to be very close.

[Gutbucket]

Volt said what I was thinking.  Get close. Put the rig on stage if you can. If not sit in the front row.  That's the acoustic recording technique that is required.

Set the recorder to record 24bit files. Set gain so as to peak around -6 dBFS.. on applause, which is almost certain to be the highest SPL content, particularly if you are wearing the rig.  Test clap loudly at home to check that (and perfect your silent stealth clap for use at the concert). If your peaks were relatively low on the previous recording, more clean gain is the first thing to try to reduce noise-floor. Use an external preamp in place of the battery box if you have one.  A Church Audio preamp or the equivalent will work fine and will power the mics instead of the battery box.  Without a preamp, if you are unable to get sufficient gain for loud claps to peak at about -6dBFS with the M-10 set to Low Sensitivity, switch to High Sensitivity (this is generically correct advice, but any M-10 users reading please correct me if its not applicable to the M-10 specifically for some reason).

There are some software noise-reduction tools, some of which are good, but doing more good than harm takes some skill and a careful ear.  It's always better to start with the least noise possible on the recording, and the process above will do that as much as possible with the gear you have.  There are a few threads around TS about this.

A deeper take on noise-

Things contributing to the noise-floor are (from difficult to easier to do anything about) :
1) The venue itself (HVAC, outside road noise, etc) - probably nothing you can do about that.
2) The self-noise of the microphones - improvement requires upgrading to mics that have a lower self-noise.
3) The recorder and how it is set - improvement may just require adjusting settings.
4) The analog input gain stage of the recorder up to the ADC - an external preamp may help here.

The last two are the ones to focus on in the short term.

FYI- In addition to the quality of the ADC (analog to digital converter) used in the recorder and the analog circuit path ahead of it, the dynamic range capability of the recorder itself is determined in part by the bit-depth at which you are recording.  Set the M10 to record 24bit files instead of 16bit, although M-10 probably only achieves an actual dynamic range of the equivalent of 19-20bits when set 24bit mode.

[kuba e]

I also have Chris Church microphones. I like these microphones a lot but I think they are not suitable for recording acoustic music. These microphones are modified to handle a high SPL which are at concerts with PA, so they have lower sensitivity and probably there are lower noise demands. I wasn't successful when I recorded acoustic music with them. On the other hand, I have to admit that I do not know if the noise was from the microphones (Chris's ca11), a preamp (Chris's preamp) or a recorder (DR2D).

The noise removal software will definitely help. I used a very simple plugin from Isotope VoiceDeNoise. I bought it a few years ago in some Christmas discount for 10USD. The name of the plugin pack was RX Elements. Now, I see that the normal price of this pack is 100USD. That seems a lot to me. Wait for Christmas or there should be better alternatives or maybe there is some free AI trained for removing the noise.

[celtic]

Thanks for the reply's.

What I'm talking about is a performance where there is PA amplification. Artists like Jason Isbell or Ryan Adam's solo etc. etc.

[grawk]

What level did your recordings peak at?  With devices like the M10, you'll want to set the levels such that you're peaking around -12db to allow for sudden volume changes.  The lower the peaks, the higher the noise is relative to the music.  If you're already peaking at -12 or higher, then you're doing what you can do, and the next step would be to upgrade equipment. 

[celtic]

The last recording with the noise, at recording level 5.5, when the artist was singing peaking around -21 or -18. Then when crowd was clapping / shouting etc. in between songs it was peaking -3 or over.

[grawk]

So it sounds like you're at the limit of what your gear can do.  I would recommend RX for noise removal if it bothers you. 

If you're wanting to stay "low profile", your next logical upgrade is probably the DPA 4061 microphones using the same battery box.

I'd also try and record some room noise either at the beginning or end of the show, so you'll have something to profile the noise with.

[celtic]

So it sounds like you're at the limit of what your gear can do.  I would recommend RX for noise removal if it bothers you. 

If you're wanting to stay "low profile", your next logical upgrade is probably the DPA 4061 microphones using the same battery box.

I'd also try and record some room noise either at the beginning or end of the show, so you'll have something to profile the noise with.

Ok, thanks.

[grawk]

It also probably wouldn't hurt to turn the limiter on and turn up slightly, so that the crowd screaming got limited, but the music didn't, but that takes some trial and error to figure out if it is worth it.

[Thelonius]

If there is a difference of 15db between crowd noise and the peak of the music then the limiter approach is probably worth it.

The only other thing I would consider is the positioning that both Volt and Gutbucket mentioned earlier (even though I think that was based on no amplification where it becomes even more critical). Getting the mics closer to the sound source (closest stack) would improve the signal to noise (i.e., music to crowd) by boosting the volume of the music and looking at options to get away from the screamers and "loud clappers" will also make a big difference. I recognize that this is not easy to do once you're at a show with an assigned seat but, as someone who records a lot of shows where the audience is a LOT louder than the music, the journey starts with seat selection. Buying a seat closer to a stack, or in the front row of the balcony as an example, can help with reducing crowd noise and allow a higher recording level. Additionally, mounting the mics in a way where your body is a baffle from these positions can help further. A limiter, above the level of the music, is also an option but, as grawk pointed out, this requires experience to ensure you don't limit the dynamics of the show.

DPAs would certainly help but they are an investment.

Good luck with your pursuit. Live acoustic music is amazing but much harder to make great recordings than electric music for the reasons you are discovering.

[Gutbucket]

^ Location, location, location.

Need to record from the right location to make a good PA-reinforced recording too, it's just a different and often easier than with a fully acoustic performance with no PA helping push a lot more direct sound out to the audience.

Front row might still work best if you can position directly in front of a stage fill speaker pointed out at the audience.. assuming that fill speaker is being used.. and used correctly.  Such a position can be best of all worlds, getting good direct sound and live transients from the instruments and backline on stage, reinforced with the PA content from the close speaker directly in front of the recording position, and the audience behind.  Otherwise you may need to back up enough though the "dead zone" in PA coverage up front until you get far enough back to be within the good coverage pattern of the PA.

If you are able to walk around prior and select your spot, carefully listening the house music through the PA or soundcheck can reveal where there is a clarity drop off.  Sometimes helps to give up the perfect stereo center and move to one side or the other to get closer and more in direct line of one of the PA stacks.  If the PA is not active, do the same while looking at the high-frequency horn section of the PA.  You want to be able to see fully down into the horn throats.  If all you can see is horn edge or walls and not down into the throat you are probably too far off-axis from the PA.  Good to get in the habit of doing both of those things whenever possible, whether taping or not, since after doing it for a while it will inform better seat selection even when all you have available are photos and seating charts.

[Gutbucket]

How much the sound of limiting bothers you is going to somewhat subjective.  Personally, I have a higher tolerance for a hissy noise floor than for obviously squashed applause between each song.  Constant low lever hiss I can perceptually ignore after a while, but heavily limited or clipped applause just smacks me in the face each time and pulls me out of the illusion.

Grawk's suggestion of recording some room noise before and/or afterward for use in training the noise reduction routine is a good one.  Just try to get only room noise without much of anything else in there such as audience chatter or instrument checks.  A few clean seconds worth is probably enough.