Topic: Low hum on recording

[divamum]

Hi!

Got to run the JB3 (superstealth, somebody in the audience carried it for me since I was onstage). Am running AT831>sp pre>JB3.

Was initially really happy with the recording but thennoitced that there is a constant low-frequency hum throughout. And there sure is - NASTY. Have NO idea what it could be.

I had the rig set up in a smallish ladies handbag - I cut holes between the compartments to run the wires so had the pre zipped into one section and the JB3 in another, and then pinned the mics into a 3rd compartment, with the actual heads just peeping out at the edges of the zipper so they couldn't be seen but were in "clear air".

Could the mics have picked up the noise of the JB3 itself?  Alternatively (assuming it isn't an external noise, and I can't for
the life of me imagine what that could be in a 2500 seat theatre) what COULD it be? I'm completely clueless!

Thanks for any suggestions of things to try and/or diagnostics to figure out where the problem is etc.

[Karl]

Could you post a short sample?  You can attach short mp3's to your posts.

[divamum]

Sure - how do i attach? I found insert image and insert link, but no insert object or attach... where's the command?  Tx
(Sorry if this is Stupid Q 101 - despite being set for HTML viewing, for some reason this puter won't display the icons on the "compose" screen, so I'm having to kinda guess what's where!)

[divamum]

DUH!  Found it (additional options - didn't see that at the bottom!)  Here it is:)

[Karl]

Hmm, interesting.  My first thoughts are that it's either from the venue's A/C, or from the soundsystem.  Even though it may not be loud enough to be noticeable/bothersome as an audience member, mics sometimes have a way of making a sound like that become bothersome.

The sound is sitting right at 70 Hz, and it's not in mono.

For this particular recording, running a high pass filter on it through a sound editing program will help it become listenable.  With opera, there's not a whole lot of wanted sound down in that range anyways.

[divamum]

Hmmm... I suppose heating system is possible; "sound system" highly unlikely since the performance is entirely acoustic.

Interesting (if annoying!).  I'm sure I can tweak it out, although this recording is for my own archival purposes only so it's not that big a deal.  The main thing is whether or not I need to address a problem in the equipment (everything except the mics is pretty new to me - that's only the JB3's third outing and the pre's 2nd, so I'm still getting to know what I've got and how best to use it).

Thanks for the input - further comments certainly welcomed....

[Karl]

I was going to mention--try taking that recording set up and do a recording in your home, then outside.  That'll be a good way to see if that hum is there or not.  If it's not, then it would support the notion that it was something from your performance.

Entirely acoustic?  I've been to opera/theater type stuff where they do some minimal amplification by either hanging mics overhead or attaching them to performers lavaliere style.

[Brian Skalinder]

The main thing is whether or not I need to address a problem in the equipment (everything except the mics is pretty new to me - that's only the JB3's third outing and the pre's 2nd, so I'm still getting to know what I've got and how best to use it).

Yeah, maybe HC system.  To rule out your gear, simply run some tests at home - record with your gear set up the same as you would in the field, and see if the problem occurs again.  If not, it was probably an environmental issue like the HC system.  If it DOES occur again in a controlled field-simulated environment, then we'll have to attempt to start ruling out each discrete piece of gear.  My money's on not being able to repeat it and the problem being the HC system.  Let us know how it goes!

Oh, never mind - what Karl said.   

[divamum]

Entirely acoustic?  I've been to opera/theater type stuff where they do some minimal amplification by either hanging mics overhead or attaching them to performers lavaliere style.

Musical theater/Theater - yes.

Opera - NO  (with the exception of a couple of houses  - eg New York City Opera - which are known to use sound enhancment). I can guarantee FOR SURE that there is no stage amplification of any kind in the house I'm singing.   

Also, often the mics you see onstage in opera are for recording/broadcast etc, not for individual mic-ing and live sound enhancement. 

BTW, this is a HUGE can of worms in opera-land, and NYCO caused a major furore when it admitted it had started mic'ing singers. 

Just to put the record straight. 

In the meantime, I'll try some other recordings and see what I get; maybe can get something tonight, in fact.  I'll post back!