Problem solving - microphone selection or placement

[Thomas W. Bethel]

As I posted in a different post in this section I am doing a radio show and the star of that show is a 1928 Wurlitzer Pipe organ. The organ console sits in a hall and all the pipes are located in the basement. The sound arrives at the hall though grates in the floor of the hall (2.5 feet wide and about 20 feet long) . At present I have my organ pickup microphones located about six feet above the grates on both sides of the organ console. The current microphone of choice is the AKG C-3000. It records the organ well but there is, as you can imagine, a lot of wind and chest noises from the pit where the pipes are located. I am using the microphone in the cardioid pattern because I do not want to pickup a lot of the room with the sound of the organ.

My question is how to I not pickup lots of wind and chest noise and can you suggest a better microphone or placement.

Thanks in advance for any suggestions. This is a GREAT FORUM!!!

 

[David French]

Omnis are more forgiving of wind noise and have the extended lows important for providing a realistic picture of the organ.

 

[Thomas W. Bethel]

The producer of the program who is also the organist does not want any additional ambience although his whole room is made out of glass, hardwoods and tile so it is rather live. That is why I have to use more directional microphones.

 

[hughesmr]

I myself would stick with the omni choice, but can you mic it closer to lower the the amount of 'room' info that the organist doesn't want in the recording (though I can't imagine WHY :? )

Mike

 

[Thomas W. Bethel]

I myself would stick with the omni choice, but can you mic it closer to lower the the amount of 'room' info that the organist doesn't want in the recording (though I can't imagine WHY :? )

Mike

More "wind" noise the closer to the grates. The top of the pipes are accessable from the grate they are that close to the grating.

I will try the Omnis for the next go around during the rehearsal.

Thanks to everyone for their help.

 

[DavidSpearritt]

Tom, it sounds like you will need to try to reduce the output of the motor and wind noise, downstairs in the pit, rather than try to mic it out.

Can you place some shields downstairs over the bellows to act as a propagation path barrier before getting to the grates, perhaps some blankets or throw-rugs. Reducing the reverberance in the pit room will knock a tiny bit of it out.

Can you remove the grates, temporarily for the performance, do you think there is any turbulence around these grates?

You have three choices/locations to remove the noise, at the source, along the path, and at the receiver (Mics), this is stating the obvious but it may give you some ideas.

 

[Thomas W. Bethel]

Tom, it sounds like you will need to try to reduce the output of the motor and wind noise, downstairs in the pit, rather than try to mic it out.

Can you place some shields downstairs over the bellows to act as a propagation path barrier before getting to the grates, perhaps some blankets or throw-rugs. Reducing the reverberance in the pit room will knock a tiny bit of it out.

Can you remove the grates, temporarily for the performance, do you think there is any turbulence around these grates?

You have three choices/locations to remove the noise, at the source, along the path, and at the receiver (Mics), this is stating the obvious but it may give you some ideas.

No one is allowed in the organ chamber, no one is allowed to stand on or be near the grates for fear of a cypher caused by foreign materal getting into the pipes. The grates are removable but they are very wide so their should be no restriction on the sound. I think I know what I need to do but I thought I would get some other suggestion. One person suggested using boundry layer microphones on the floor but I am not in favor of that proposal.

The organ sounds good in the room but the producer wants more presence and with more presence comes more noise from the organ it is a catch 22 proposition.

 

[Cucco]

So, what we have then is the necessity to use omnis but the desire not to pick up ambience --

Seems like a reasonable one to me (if not completely whacky)

Place the omnis where you've been placing the cardioids, but baffle behind the omnis with a square or so of Auralex. This will keep the room bleed to a minimum, but the sound still full and unfettered by wind.

This is the reverse (at least in my mind) to one of my favorite ways to mic cello or string bass during concerts which is to place a square of auralex on the floor, place an omni mic on it directly below the instrument. It kind of acts like a BL mic, but a bit warmer.

J.

 

[Sonarerec]

Your description of the tone openings imply that the instrument is in a theatre-- yes? And if it is a typical movie house it probably isn't very reverberant.

I would try a few things, beginning with explaining the laws of physics-- the further back you are the less wind and mechanical noise. The wind noise does not come from the top of the pipes, but rather from the mouth of the pipe. Also, if you are looking down into the chamber then the mics are literally looking at the noisiest components-- the chests, reservoirs and wind lines.

I would stick to cardioids just a LITTLE further out and blend in a pair of omnis that have the HF rolled off-- that will give some body and also something of a center image, which from your description must be a problem.

I would also choose a mic that is not so heavy on the top end. Also, remind the producer and organist that even Wurlitzer voiced their instruments with the theater patron in mind, and they were sitting in the SEATS.

Rich

 

[Thomas W. Bethel]

Your description of the tone openings imply that the instrument is in a theatre-- yes? And if it is a typical movie house it probably isn't very reverberant.

I would try a few things, beginning with explaining the laws of physics-- the further back you are the less wind and mechanical noise. The wind noise does not come from the top of the pipes, but rather from the mouth of the pipe. Also, if you are looking down into the chamber then the mics are literally looking at the noisiest components-- the chests, reservoirs and wind lines.

I would stick to cardioids just a LITTLE further out and blend in a pair of omnis that have the HF rolled off-- that will give some body and also something of a center image, which from your description must be a problem.

I would also choose a mic that is not so heavy on the top end. Also, remind the producer and organist that even Wurlitzer voiced their instruments with the theater patron in mind, and they were sitting in the SEATS.

Rich

Thanks for the ideas

This organ is in a museum not a theater. It is in a room that is made out of glass, wood and ceramic tile so it is very live. The concert has about 150 people in attendence and the museum is in the middle of a forest but near enough to a road that once in a while we can pickup trucks going by and motor cycles wizing by in large groups. The producer of the show does not like a lot of ambience for what ever reason.

Thanks again....

 

[Thomas W. Bethel]

I did another radio show and this time,at the organist urging, I used his AKGs 224s. In case you are not familiar with the AKG 224s they are cardioid dynamic microphones with two capsules in them and a crossover so that one capsule is picking up the highs and the other one the lows. (picture here http://www.ebay.com.sg/viItem?ItemId=7334638819) When listening to the playback of the show the organist did not like the sound of the organ and he said it was not grand enough. The next show is in September and I plan to use my AT4050s in Omni just to see how it goes. This is like Chinese water torture since I have to wait three months to try out the next micing setup. I did suggest that the organist and the cast listen to the playback of the rehearsal while they were eating lunch which would give me some feedback and them a chance to hear what they are doing and if there are problems they can be fixed by showtime. The cast is made up of all professional (read opera) singers but they have little knowledge of proper mic technique and in a couple of instances they were actually getting closer to the microphones for loud passages and backing off for soft. Oh well... the saga continues.......