Thanks for those who answered my query. The reason behind the question
is that I'm building a reflector trying a variety of sizes and focal
lengths. I'm targeting bird calls. One of my aims was trying to get a
few more dB for my mics (Shure WL 183).
There a several materials available ranging from metal, plastic (eg.
umbrella), cardboard and fiberglass. Durability, ease of construction
and weight are factors but is the difference in bD reflected of the
surface going to be a major consideration?
David
Rich Peet wrote:
> In my next version of the cube I will try very dense absorbtive foam
> and not use wood. The gain of the boundary does not seem to be true
> hemispherical. I have read reports on both sides of this. But I
> figure if I keep using the very quiet mics types I really don't need
> the boundary gain from what I am seeing in the field. I am just not
> finding my mics with there high outputs can be driven to +60db on the
> preamp. I would say the mics have too high of a noise but they are
> out performing my ears so I can not complain.
>
> Rich
>
> --- In "John Hartog"
> <> wrote:
> >
> > Hi David,
> > It's important here to distinguish boundary from other barrier
> techniques.
> > For boundary mics the direct and reflected sounds that combine at the
> > reflective surface give several dB of wanted free gain. For other
> > barrier techniques, like a Jecklin Disk, an absorptive surface is
> > ideal to reduce unwanted phase cancellation between direct to the mic
> > and reflected off the barrier sounds.
> >
> > -John Hartog
> >
> >
> >
> > --- In Secomb's <secowlet@> wrote:
> > >
> > > Hi all
> > > There have been a variety of DIY projects that have been floating
> > > around. Which material that is used is essential component of any
> such
> > > project. I have been under the assumption that harder and smoother
> the
> > > material, the greater the sound would be reflected. To me Rich
> making
> > > a cube array with wood made sense but a softer material such as
> high
> > > density foam will result in less sound reflected towards the mic.
> > The
> > > concept of emphasising a particular range of frequency is
> interesting.
> > > A little while ago, a mouse pad was used as a Jenklin disk (I think).
> > > Again a softer material with a slight texture will give less dB when
> > > compared to wood for instance .
> > > With those more experienced in sound recording is there a rule of
> thump
> > > what are the reflective properties of a variety of material that is
> > > used in DIY projects. It appears not only the degree of sound that is
> > > reflected to consider, the tonal quality is also important.
> > >
> > > David
> > >
> > >
> > >
> > > --
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> >
>
>
>
>
>
>
>
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> A listening room is not nature."
> Klas Strandberg
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