Need tips on recording Owls

[rognancameron]

I will be visting Yosemite National Park soon and would like to make some voice recordings of Great Gray Owls. I have a Sennheiser ME66 shotgun microphone attached to a K6 Power Module. I also have a 24 inch parabalic dish with a ME62 microphone. I will be recording in MP3 format with a small digital recorder made by Iriver.

Which set up will be more appropriate for recording this owl? I am concerned because they call at a very low frequency range about 150-300 Hz. Also, will I need to shift the filter button on the K6 module to the left since it is at such a low frequency? Any additional advice would be greatly appreciated.

Thanks

[ermine]

I will be visting Yosemite National Park soon and would like to make some voice recordings of Great Gray Owls.

your parabolic dish may be too small for this job. The lowest frequency at which the dish can give gain is when the diameter is at least one wavelength long, ideally two or more. Sound travels at about 340m/s in air at sea level and room temp so one wavelength at 150Hz is 2.2m, about 88 inches. Your dish cutoff frequency is therefore 340/(0.0254*24), about 500Hz so the lowest pitch and first overtone of the owl will be very seriously attenuated.

How far away do you expect to be from the owl, and does the Iriver give sufficient gain at a low enough noise for this application? Recording compressed means your options for post-processing the sound will be limited - a HiMD recorder capturing uncompressed PCM is relatively cheap and may be a better match.

Leave the filter in - Sennheiser's K6 spec (http://www.sennheiser.com/sennheiser/icm_eng.nsf/root/03279#) shows it 6dB down at 100Hz (4dB at 150Hz) which you could compensate for in post-production if you felt the need. You would struggle to hear the difference on the owl sound alone and the filter will help you avoid saturating your recorder with wind noise and/or ambient rumble.

I'd want to practice beforehand with some more common birds at your anticipated target distance with this rig to make sure you aren't asking a little bit too much of the recorder's mic preamplifier noise specs. That would be my main concern but I have no experience of the Iriver - it may be fine. The ME66/K6 are a great start for the front end!

[rognancameron]

Thanks for the advice,

So let me see if I got this right. I should not use the dish because its too small, instead just use the ME66 microphone. I want to record the owls at distances less than 50 meters (hopefully less than 25 meters) and during ideal conditions (no rain or wind). I should leave the filter on (switched to the right). The Iriver records compressed mp3 files at 320 kbps. I have used this system for recording song birds and the quality seems pretty good. I converted the mp3s to wave files. Then I do my post processing with everything in wave format. Will the sound degradation be worse or better when dealing with owl calls?

any more advice greatly appreciated

and procepmyour parabolic dish may be too small for this job. The lowest frequency at which the dish can give gain is when the diameter is at least one wavelength long, ideally two or more. Sound travels at about 340m/s in air at sea level and room temp so one wavelength at 150Hz is 2.2m, about 88 inches. Your dish cutoff frequency is therefore 340/(0.0254*24), about 500Hz so the lowest pitch and first overtone of the owl will be very seriously attenuated.

How far away do you expect to be from the owl, and does the Iriver give sufficient gain at a low enough noise for this application? Recording compressed means your options for post-processing the sound will be limited - a HiMD recorder capturing uncompressed PCM is relatively cheap and may be a better match.

Leave the filter in - Sennheiser's K6 spec (http://www.sennheiser.com/sennheiser/icm_eng.nsf/root/03279#) shows it 6dB down at 100Hz (4dB at 150Hz) which you could compensate for in post-production if you felt the need. You would struggle to hear the difference on the owl sound alone and the filter will help you avoid saturating your recorder with wind noise and/or ambient rumble.

I'd want to practice beforehand with some more common birds at your anticipated target distance with this rig to make sure you aren't asking a little bit too much of the recorder's mic preamplifier noise specs. That would be my main concern but I have no experience of the Iriver - it may be fine. The ME66/K6 are a great start for the front end!

[ermine]

Thanks for the advice,
So let me see if I got this right. I should not use the dish because its too small, instead just use the ME66 microphone. I want to record the owls at distances less than 50 meters (hopefully less than 25 meters) and during ideal conditions (no rain or wind).

Yep, that's the general angle. 50 meters is a reasonably long range. I don't know how loud these guys are, certainly European owls aren't tremendously loud, maybe your birds are less shy. I'd recommend you test your rig out at home at 50m from a bird which is a similar expected volume, to make sure your recording won't be drowned in noise from the mic input stages of your recorder. You will get a much stronger signal at half the range - the sound will be four times as loud, and stronger relative to the reverberant field which will make it clearer. There are things you can do if you find hiss to be a problem at your expected target volume and range but they involve $ so you want to test first.

You can confirm for yourself the performance of the parabolic dish at low frequencies. Get someone to aim the mics at you (outdoors) from about 50m away and read out a passage of a book at normal conversational volume - do not raise your voice. Record with the parabola and repeat the experiment with the ME66. Male voice goes down to 300Hz - you will find the parabola recording less noisy but less intelligible than the Me66. If you get a woman to read out the same passage you will probably find less loss of intelligibility with the parabola. You then need to consider that the owl's vocalisation goes an octave deeper than you ;)

To the human ear you will get pretty decent results recording 320k mp3 in the field. Recording compressed does limit some types of scientific analysis of your recordings but from an aesthetic point of view that isn't a problem.