Dan Dugan wrote:
>> > A cassette tape machine like the Sony TCM-5000EV can successfully
>>
>>> replicate most bird song via its 3.5" speaker with output rated at
>>> 700mW maximum. A more powerful amplified speaker could be useful
>>> because it produces the same 700mW with less distortion.
>>
>
> WALT
>
>>I will repeat, such output may sound the same in a room, or with your
>>ear at the speaker, but will fall off much more rapidly in the outdoors
>>than a natural call will. Try checking with a sound meter. Or going out
>>and walking out for a couple hundred feet.
>
>
> To compare sound levels they have to be measured at the same distance
> in the same environment. I doubt that the output level of a
> recorder's speaker is anywhere near as loud as a bird. It "sounds the
> same" at one meter, but remember the bird is singing five meters from
> you, not one meter, and sound level falls off by the inverse square
> of the distance. At one meter the bird would be a lot louder! The
> difference between one meter and five meters distance, for example is
> 14 dB.
Maybe because the bird is a more focused sound source, I've found they
seem to fall off less rapidly than speakers. And I know the rules.
It's one of the problems with trying to get a handle on bird song
intensity. At our usual record distance the bird's song is barely
showing above ambient on a meter. Not going to be a very accurate measure.
That's a lot of the problem in using playback. It quickly falls to where
it's merging with ambient. And we would really be after something that
reliably get's the bird's (or frog's) attention. It needs to stand out
enough.
In many places where we might use playback, ambient is less than ideal.
I know that's the case in what I need.
Walt
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