We've sent a verification link by email
Didn't receive the email? Check your Spam folder, it may have been caught by a filter. If you still don't see it, you can resend the verification email.
Started December 20th, 2010 · 12 replies · Latest reply by strangely_gnarled 12 years, 9 months ago
As a newcomer to FS, my first objective is see what its all about,to check out sounds etc and then offer some of my own work.
I have been involved in audio for many years, in broadcasting and commercial applications and my experience goes far back into the days when Mullard was king and large glass tubes glowed in the dark.
I have been listening to a number of "live" bird recordings and several, which I will not name, fall far short of what one would expect. They are just that recording of sounds and everything else available.
May I give a few tips.
1. Microphones. Do not use hand held microphones, especially el cheapo ones that have microphonic cables and housing, there is nothing worst than crashing, banging of a microphone that keeps sending the VU meter off the end scale. Always use a microphone stand and check those cables before using them to ensure they are quiet.
2. Use a directional microphone, not a cardioid or wide angles mic, who wants sounds from behind you when you are recording a bird in front of you. "shotgun" mics are good but expensive.
3. Try to make or get hold of a parabolic reflector, they are very directional and will boost the natural gain of the sound into the mic. I have even used an over sized kitchen wok !!
4. Birds hit some very high frequencies and these are prone to severe distortion on peaks, try to keep the VU meter on 0 when those peaks arrive at the microphone.
5. A bird recording is only as good as your equipment, poor ground connections on cables and decoupling of preamp circuits can introduce hum and other unwanted noise.
The recording.
How many recordings do we hear with so much background noise, cars, police sirens, aircraft, dogs, you name it, we live in a very audio polluted situation, unless you are in the mountains of the Himalayas.
Birds are most active at dawn and sunset, get into your car or on your bicycle and get out of suburbia and into the country side, away from the noise. Choose a calm day, there is nothing worse than wind howling across a mic.
Set the microphone as far away from your recording equipment as possible, that negate your size 12 boots stomping around in the undergrowth from getting into the act.
Radio mics can be used but unless you are after a very rare bird, I tend to dismiss them.
If you cannot get away from your locality, try recording early on a Sunday morning, when half the neighborhood is recovering from the previous nights revelries.
Many of my recordings have been made on a JVC professional portable recorder using Fuji Metal tapes, this was acquired from a broadcast station. Its heavy and built like a tank and has a massive 8" flywheel.
I also have digital recorders but I always fall back on the old JVC. Transferring them to the computer as Wave files.
Make long recordings and edit them to select the best passages. I have been using for many years a old established program called Cubase (R) It has a great number of editing functions of equalising, filtering and adjusting bandwidths and frequency responses. Its the audio version of Photoshop (R) The program is not cheap, but the results are incredible
Another old establish program is GoldWave, easier to use and very user friendly.
There are a lot of programs out there, some good some ho hum, some you need a degree in Audio Technology just to turn them on. The choice is up to you and what you want to do.
As I mentioned above re Photoshop (R), They say the camera does not lie, but one can make it a lot more truthful, the same is with sound recording and editors.
Do a search for the parameters of a Parabolic Dish on the net. They are easy to make using lightweight materials
Hi there,
many bird recordings you may find here are not bird-oriented, they rather try to catch birds andeverything else (atmosphere-oriented). But thank you anyway for your experienced advice, it is much appreciated. We all look forward to listen to some of your own samples, it would be nice
Best wishes
D
As dobroide says, often people are interested in ambient field recordings observing and documenting the kind of undesirable sounds you mention, but your advice about picking out individual sounds is certainly interesting and there are no doubt recordings on freesound that could have benefited from it.
Maybe you'll inspire me to attempt a DIY parabolic reflector.
sploddy
4. Birds hit some very high frequencies and these are prone to severe distortion on peaks, try to keep the VU meter on 0 when those peaks arrive at the microphone.
With modern digital equipment, people tend to advise you record in 24bit and aim to leave yourself plenty of headroom; if you expect your peaks to reach 0 there is a strong chance of bad distortion when (not if) they exceed that. I find it hard to convince myself to go that low sometimes (depends on how dynamic the source is), but have often seen people say best practice is to aim around -12db, or perhaps to leave amps at unity gain (at least in situations where that will provide close to the correct level). I'm not really an expert here.
There are a lot of programs out there, some good some ho hum, some you need a degree in Audio Technology just to turn them on. The choice is up to you and what you want to do.
Adobe audition has some good features for spectral editing these days I believe. Maybe a better choice than Cubase for editing field recordings etc. There's some decent free open source software about as well.
Must put some more sounds up one of these days... and make some more, more importantly...
Cheers
Not quite sure what happened but I made a reply and it vanished into thin air when I hit submit
I commented on ambient recordings, and my main thought was that ambient recordings can be very good and interesting to paint an audio picture, but why spoil them by dragging the mic along the the pavement or belting the living daylights out of it especially cheap plastic mics which are notorious for microphonic housings and cables. Listening to recordings that sound like they have been recorded in your pocket along with loose change and a bunch of nuts and bolts is not much fun to listen too.
The decibel is a very confusing element to most people, on its own it does not mean a thing, so many dbs plus or minus? plus or minus what? The scale of the Decibel is logarithmic, that is to double the the power one has to raise the level by 4db. In broadcasting 0db is the pivotal figure which is a level set on test equipment of 1mv @ 1000hz into 600 ohms which give lowest N and D readings on a calibrated test unit. From that point + and - reading are thus read on a Volt Unit meter (VU) If the frequency response of the incoming signal between 35hz and 15,000 hz is flat then this is the perfect signal. As such any frequency applied in that frequency range will be of a constant and similar output from the amplifier.
This is a mere thumbnail sketch and one should refer to technical manuals for further explanations for units such as dbm etc,
Parabolic reflectors have one thing in common they all follow very strict formula of curvature and depth and placement of the sensor, in this case the mic is very critical and has to be "tuned" same as a Sat TV dish.
In fact I have used a 1.2m offset sat dish at home but too heavy and cumbersome to drag around the bush. One may get away with a very large photographic umbrella made of plastic compounds, but the ideal material is a firm and solid substance such as aluminum, fiberglass or other carbon compounds. For large dishes that can be carried on the surf bars on a vehicle that can be made in two halves that are hinges or in quarter sections that can quickly be assembled. As mentioned an oversized kitchen wok has been used with some success.
Most of my main recordings are copyright, however I have added one sample of and evening call of Magpies (Australian) at the start and finish of the clip with a Currawong, Blackfaced cuckoo shrike, Raven and New Holland Honeyeaters getting in on the act. This recording was wade about 200 metres from the main source and has a feeling of depth and open space. It was recorded on Fuji Metal Pro tape, with full equalisation and noise reduction with JVC portable broadcast recorder. Built like a tank and weighs a ton, esp the flywheel.
I think if you click on my Name it takes you to the sound clip. Still making my way thru the undergrowth of this website
Hmmm apparently not its here anyway http://www.freesound.org/usersViewSingle.php?id=1946391
Cheers D
I think if you click on my Name it takes you to the sound clip.
In the forum, clicking on the Freesound waveform under the name will take you to the sounds. Thank you for an interesting post.
There is a very nice bird oriented website, www.xeno-canto.org - about 70 000 samples in about 30GB of "birdish" material and growing. Would be nice to encourage them to collaborate with freesound.
ayamahambho
There is a very nice bird oriented website, www.xeno-canto.org - about 70 000 samples in about 30GB of "birdish" material and growing. Would be nice to encourage them to collaborate with freesound.
A few questions/comments.
First of all I totally agree with this post. I am sure that there are some members there, with the number that they have, that wouldn't mind contributing to FS. Plus, many of the recordings are excellent. Maybe someone could contact the webmaster(s) and ask.
Also, since parabolic mics are mentioned here I figured this would be a good topic to ask. I have a parabolic mic set-up, but the actual microphone on it is pretty bad. Could any microphone of a similar size be used to replace it? Could a single stereo mic work? I guess it wouldn't be as directional, but most of the times I need to use the parabola because of distance there are several birds/insects calling and it would be nice to have it in stereo instead of just part of the ambience. Regular stereo mics, at least ones built-in to the recorders that I have, do not work that well at these distances. Could this work?
soundbytezayamahambho
There is a very nice bird oriented website, www.xeno-canto.org - about 70 000 samples in about 30GB of "birdish" material and growing. Would be nice to encourage them to collaborate with freesound.A few questions/comments.
First of all I totally agree with this post. I am sure that there are some members there, with the number that they have, that wouldn't mind contributing to FS. Plus, many of the recordings are excellent. Maybe someone could contact the webmaster(s) and ask.
Also, since parabolic mics are mentioned here I figured this would be a good topic to ask. I have a parabolic mic set-up, but the actual microphone on it is pretty bad. Could any microphone of a similar size be used to replace it? Could a single stereo mic work? I guess it wouldn't be as directional, but most of the times I need to use the parabola because of distance there are several birds/insects calling and it would be nice to have it in stereo instead of just part of the ambience. Regular stereo mics, at least ones built-in to the recorders that I have, do not work that well at these distances. Could this work?
Hi soundbytez.
Could a single stereo mic work?
More info than you were asking for I'm sure, but my off-the-top-of-my-head musings on stereo mics and parabolas.
With a reflector a stereo mic (with closely placed capsules) will only capture a two-channel mono sound and because of the orientation and polar sensitivity of each capsule, they will each only point at one side of the dish or the other, and so will lose sensitivity relative to a single mic pointing at the dish centre. If the mics are spread and separated to the left and right (or up and down) they will each focus on a different vector and produce a "quasi-stereo" result which could, for instance, produce an exaggerated stereo effect if pointing at a flock of birds. This effect should more accurately be described as two-channel rather than stereo since the two channels are unlikely to overlap with the correct polar pattern to produce a proper stereo field.
In theory a stereo mic in a parabolic reflector doesn't work particularly well because the reflector only has one focal point, which is where the mic element is supposed to be placed. Besides, if you are monitoring a point source at some distance the sound itself has no "stereo content". Directional information can be simulated by how the sound is panned in a stereo reproduction system, and the phase/time-delay between the L and R channels will be close to zero - info our brains use to determine that it's a distant sound and not a close one. This zero-delay info is usually smeared, or sometimes totally lost, when we listen on loudspeakers because of their positioning. Headphones are much better at retaining this depth.
If you want to place the point sound in a panoramic environment it must be mixed with an ambient field (which might include reflected components of the point sound - imagine a screaming Eagle in a canyon). Either way one needs more than a stereo mic and single reflector to capture or create that.
Two mics each with there own reflector can capture time-correlated but different sounds, depending on how each is oriented, but it still can't legitimately be called "stereo" since the whole purpose of the reflector is to eliminate as much of the soundscape as possible to isolate the point source cleanly.
If you own a stereo mic you could try it and see how well it works. It still might give very usable results, but I wouldn't consider purchasing a stereo mic to use here (not that I think you were).
Hope that makes sense.
Wibby.
About reflectors.
Listen carefully if your parabolic reflector does not produces "room like reverb" effect; I heard some FS examples (don't remember which ones, it was some time ago) which were recorded with refoectors, and they are affected with non-proper reverb rumble. It becomes more audible when you resample down (pitch/tempo) your bird sounds. So my gentle guess would be - no tto amplify with the reflector what comes from the front, but rather to filter what comes from behind, and to use better mic/amp equipment.
In theory a stereo mic in a parabolic reflector doesn't work particularly well because the reflector only has one focal point, which is where the mic element is supposed to be placed.
True, but in contrast to light, the focus on a mic parabola consists of spheres ( diam = frequency dependent ) so you can experiment with being off focus.
This might also be of interest
http://www.telinga.com/stereo.htm
Two omnis in a dish
http://www.freesound.org/samplesViewSingle.php?id=123037
A very interesting article Benboncan. It opens up the debate nicely and puts in relevant stuff gathered from practical experience.
Another difference between a radio/light telescope parabola and a mic parabola is that the mic doesn't have the "depth of field" and "resolution" problems that telescopes do, so the actual "focal length" of the reflector is not so critical. I haven't read much about them, but just looking at pictures of commercial units compared to parabolas I've drawn using schoolboy maths I'd guess they're typically between 10 to 100 metres. A telescope has to resolve three parameters - Width, Height and intensity/colour but a mic only resolves one - intensity/frequency. This makes the geometry much less critical, although not irrelevant.
Well that's enough armchair theorising from me today - I'm off to replenish my cup of coffee.