let me reformulate my question then - what are the high cut-off points of the woofers and low cut-off point of the small one?
good points and I agree
I think Pluto can be said to be omni, my criterion for an omni from perspective of what I judge important for realistic sound reproduction is uniformity of polar response in any given lateral plane but not necessarily across the full frequency spectrum but only up to a certain frequency
question is what frequency? I hypothesize that it is question of power spectral density of musical sounds
what has to be spread evenly around the speaker into the room for a speaker to be said to be omni is that part of the frequency spectrum which determine the basic waveform/transient shape of a musical sound by which our hearing sense can identify it
I hypothesize that this is a prerequisite for the PE to work with regard to all lateral reflections in the room
furthermore the idea of the flooder is to take care also of vertical reflections - especially of the floor reflection as it is clearly detrimental to realism of sound reproduction
would be interesting to discuss different designs of omni lenses or lack of - how they affect high frequencies etc. would you say the B&O design is the best of the lens type?
http://www.bang-olufsen.com/graphics/bogo/media/LOUDSPEAKERS/BeoLab5/img_beolab5.jpg
http://www.bang-olufsen.com/graphics/bogo/media/LOUDSPEAKERS/BeoLab5/img_beolab5.jpg
this type of lens is designed so that:
these are generaly good ideas, it is a good lens
but question is whether low pass filtering of vertical reflections is the best we can do, cylindrical sound source like Beveridge ESL is certainly better and perhaps a flooder can be also better at handling those reflections (although it does it in a bit different way)
ahh, memory is beginning to function 😀
with 6mH on 15", and 4mH on 10", I can safely claim that xo points was quite low, on all drivers
but with a non-directive speaker
I have suspicion that there will never be a well defined xo point
I've measured a paper deflector which looks really awful. Have to make it more rigid.
An externally hosted image should be here but it was not working when we last tested it.
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you make it sound like you know
are you thinking of FR driver used in non-directive or very low directive omni design
or in an 'ordinary' higher directive design 😕
may I remind you that a few of us are suggesting omni design without any diffusor
btw, if frequency 'rolloff' is equally the same in all possible angles, you have a 100% non-directive omni, right ?
Any piston driver eventually starts to beam. The bigger the driver the earlier (lower in frequency) it starts. Fullrange drivers are no exception.
Please define "non-directive omni design" and "ordinary directive design". I don't know what kind of loudspeaker implementation those terms describe.
higher directive means narrower beamwidth
it changes with different angles
like you described in your own previous post
if beamwidth doesn't change, but is equally the same, you have a non-directive speaker
an omni with no change in beamwidth, hence non-directive
the difference is that the frequency rolloff remains the same
it changes with different angles
like you described in your own previous post
if beamwidth doesn't change, but is equally the same, you have a non-directive speaker
an omni with no change in beamwidth, hence non-directive
the difference is that the frequency rolloff remains the same
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Thank you markus76,
It was indeed my intention to extend the high end of the Pluto.
rob g,
You make excellent points.
Omni enough!
To clarify, this is the image of the tweeter dispersion above 3khz.
Pluto has 360 degree dispersion up to 3khz. Crossover point is at 1khz with the small bass mid operating with broad dispersion, extremely even power response right through its working range.
This is the whole point of the speaker, it is a constant directivity design, reflections from any direction contain the same spectral content as the direct sound up to 3khz and into a very broad angle listening from the front.
Since the reflections are tonally similar they should not change the sound we hear directly to the same degree as a speaker with poor frequency dependent off axis response. listen closely enough and this is an asset.
Obviously some will argue Pluto isn't a true omni since it does not radiate treble energy at all frequencies in all directions.
or said in another way
you have changed a complicated beam into a simpler frequency rolloff
hence its not really considered beaming any more
just plain 'simple' rolloff, in all angles
that said
I would only attempt this as a multiway speaker
3way is probably optimal
you have changed a complicated beam into a simpler frequency rolloff
hence its not really considered beaming any more
just plain 'simple' rolloff, in all angles
that said
I would only attempt this as a multiway speaker
3way is probably optimal
but isn't that where they all start to beam, more or less
I think it has been stated before that the only driver that doesn't need omni placing is a woofer at its lower frequencies
its already omni, by nature
so, the higher the frequency, the more difference it makes
but you are suggesting the opposite now ?
Pluto isn't beaming at all at 3khz it is extremely broad dispersion with even power response into the high treble. Hence the 1khz crossover.
If you chose a bigger drive unit the speaker would cease to be as an effective point source and you would have to drop the crossover frequency even lower to avoid beaming. You might be able to do this with appropriate equalization with the Aura driver SL uses for the treble (or a Peerless fullrange 2 inch drive unit but power handling would drop too.
No need to argue, the Pluto isn't a true omni. There is no real true omni (as far as I know). The question is: how much omni is omni enough? Thinking this through to the end we end up with this questions which is still unanswered: "What does a reflection pattern (level, angle, number, spectrum, delay) have to look like to generate a plausible sound perception from a 2 channel recording?"