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genericaudioperson@hotmail.com wrote:
> When I say "bounce off the floor backward" what I mean is this:
> bass response is omnidirectional
Already from this it follows that cabinet angle with respect to floor is
irrelevant in the context of what you want to address.
> basically, what i'm thinking is this: let's say a studio
> designer makes the back wall slanted so the sound deflects
> at an angle rather than bouncing straight back at the listener.
This is to prevent a midrange problem called flutter echo, the
twaaaangggg of an empty concrete room is an example of that type of
reverb.
> ceiling at an angle and then bounce in all myriad of directions.
> so you don't get slap back.
Slap back does not apply in the bass range, it is - as indicated above -
a midrange thing.
> the advantages to doing this seem so obvious to me,
With all due respect - it is a very good question to ask - you need to
understand that what you suggest is intended to help with a bass problem
that does not exist because of the large wavelength of bass compared to
the wavelength of the room.
Bass does not zingG around in a living room sized room like rays from
Flash Gordons ray gun. Midrange occasionally does, also low midrange is
likely to suffer from frequency response issues in case it is influenced
by reflections from wall, floor or ceiling.
Very many room response measurements contain a dip around 250 Hz caused
by the first reflection from the floor between loudspeaker and listener.
Place a table or a mixing desk between listener and loudspeaker,and the
reflection will have a shorter route to travel, ie. arrive less delayed,
and consequently cause a problemer higher up in the midrange and -
literally - confuse the issue in terms of perceiving the spatiality in
the recording. This stuff is what consultants living is made off ....
O;-)
> but people who are much smarter than me keep indicating problems
> that i don't understand.
Don't worry, learning is like that. More reflections is - with modesty -
better than a few, because they will cause more, but less noticeable
colourations, provided that they do not arrive too close to the direct
signal from the loudspeakers and provided that the total amount of
reflected energy is not too large, whatever that may be - one indication
of such a problem may be that the recorded space is not suffiently
perceived.
A loudspeaker problem called delayed resonance is also a great destroyer
of spatial perception if it occurs, I can still recall the listening
experience when I listened to the large horn loudspeakers with Tannoy
12" units that I ended up purchasing from Steen Duelund around 1977,
reverb - especially artificially added reverb - was so much clearer
perceived when the audio was reproduced by the compression driver than
when reproduced by his modified 8" units with acoustic lenses. Not that
they did not have "issues", but they were more precise in the time
domain than oversized paper membranes.
> i feel simultaneously smart and dumb right now. kind of strange.
Here is an experiment for you to put things right in your understanding
of the influence of reflections. Find the place where a mirror placed on
wall, ceiling or floor or table allows you to see your loudspeaker in it
when sitting in your listening chair. Place some kind of absorber on
that location, and listen for the change in the sound.
I don't know exactly what is available there, but there may be more
information about this and other room issues on the website of the guy
that sells RealTrap sound absorbers, http
/www.realtraps.com. It IS
possible to diy such stuff, and bookshelves and paintings on canvas have
excellent acoustic mileage if well applied, but such items may come in
handy ready made in some context.
Mineral fiber products generally make good absorbers wisely deployed,
but they do need to be well contained so that they do not leak out in a
domestic - or other - environment and they can be quite unpleasant to
work with or on, which is why getting some absorber of some kind from a
nearby merchant can be nice if such acoustic tools are needed.
Diffusing single sharp reflections is another way to solve issues caused
by them, too much absorption can make a room dull and boring to listen
in. It can get quite unsimple. You may want to subscribe to the
newsgroup alt.sci.physics.acoustics, it is a good place to read, and
they are a helpful lot over there.
Kind regards
Peter Larsen
--
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* My site is at:
http/www.muyiovatki.dk *
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