Can't see how that would work, since you should at least have an octave between the bounce and XO point for it to be far enough outside the passband.
Crossing at 300 Hz means the midrange would need to be some 200 cm (78 inches) above the floor for the bounce to happen around 150 Hz.
When we put the woofer very close to the floor, there is no bounce, and no cancellation, the boundary is supporting the wave.
The same way that adjacent drivers act as one at lower frequencies.
Or waveguides support the wave.
The only bounce cancellations to avoid here are for the midrange(floor and walls) and tweeter(walls).
Turn this all upside down if you hang 'em from the ceiling.
The same way that adjacent drivers act as one at lower frequencies.
Or waveguides support the wave.
The only bounce cancellations to avoid here are for the midrange(floor and walls) and tweeter(walls).
Turn this all upside down if you hang 'em from the ceiling.
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Yes, and a typical midrange driver some 90-100 cm above the floor will have the main cancellation at ~250 Hz. Meaning it should be crossed at ~500 Hz for the cancellation to be well outside of the passband.
Which is why I cant get my head around why speakers who have taken this into account (Gradient 1.4 for instance), cross at 300 Hz
The cancellation of a couple decibels is being used as an aid in getting the desired rolloff. It's small and narrow and can help shape the 'knee' of the high pass.
Without(and sometimes with) impedance compensation, even steep filters can be weak getting started,
so the little notch can give the filter a little zetz [a poke, a prod, (in cooking a little zing)].
Without(and sometimes with) impedance compensation, even steep filters can be weak getting started,
so the little notch can give the filter a little zetz [a poke, a prod, (in cooking a little zing)].
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...and some 200 cm beneath the ceiling, I assume? So your room needs to be four meters high, at least?
Best regards!
What's with the attitude in the responses to this thread?
Ceiling bounce is not the topic of this thread (it's related yes, but not what this thread is about).
We have a general design pattern here that should lessen the issue, and it's a simple question of why most speaker designers choose to not take advantage of this.
Ceiling bounce is not the topic of this thread (it's related yes, but not what this thread is about).
We have a general design pattern here that should lessen the issue, and it's a simple question of why most speaker designers choose to not take advantage of this.
There are many reasons...
Why the success of a little speaker such as Ls3/5a? Because it is free standing and has a size ( the woofer) that cannot make any damage. Free standing means that you can position the boxes in a way that they please you, which makes a happy customer and a diligent audiophile.
On the other side you find the Bigger Is Better club...but those you see also in other sectors.
In the middle there's the spousal problem, SWMBO, WAF, bridal intromission with our passion.
That brings to design monstrosities, either. Small, but powerful> more little woofers OR one big woofer, laterally. There are many more examples...
Why the success of a little speaker such as Ls3/5a? Because it is free standing and has a size ( the woofer) that cannot make any damage. Free standing means that you can position the boxes in a way that they please you, which makes a happy customer and a diligent audiophile.
On the other side you find the Bigger Is Better club...but those you see also in other sectors.
In the middle there's the spousal problem, SWMBO, WAF, bridal intromission with our passion.
That brings to design monstrosities, either. Small, but powerful> more little woofers OR one big woofer, laterally. There are many more examples...
Yet you see most 3-way floor standing speakers could easily place the woofer lower on the baffle, but chooses not to do so for some reason...
Even most of Troels Gravesen's 3-way designs doesn't do so either.
So what gives? Only reason I can think of is that in the midst of all the other room effects, and general compromises that goes into a design, floor bounce isn't worth caring about
Even most of Troels Gravesen's 3-way designs doesn't do so either.
So what gives? Only reason I can think of is that in the midst of all the other room effects, and general compromises that goes into a design, floor bounce isn't worth caring about
Have you designed 3-ways with both layouts (woofer(s) up or down) or otherwise compared different layouts with different music genres, recording/mic techniques, speaker locations, listening locations, rooms? Or are you just asking kinda recommendation how to choose in order to avoid some problem(s) not yet known? Or is this just technical curiosity?
I have some experience, opinions and own theories which I could list very shortly.
It's purely technical curiosity
We have a design pattern which seemingly has some advantages, but isn't widely used. And that makes me question why. Would love to hear some of your experiences on this topic!
Hearing is able to adapt to reflections, both early and delayed. Effect of floor bounce is not that bad as simple measurements indicate. This is probably some combination of evolution and learning.
Recording method i.e. type and location of microphone, distance to microphone, recording venue and possible post processing play significant role here especially with human voice but also with acoustical instruments which are not large.
Sound could be quite unnatural without adequate reflection link with room boundaries if recording does not include any reflections or recorded instruments were not in the same acoustical environment; real or processed. Instruments could sound floating almost like in anechoic; too far from ground or anything else natural for typical listening environments. This could also be stressing to listen, ime.
Reproduction with speakers could actually sound quite natural if voice was recorded close to mouth/instrument without much reflections/ambience and possible with some near field effects, and speakers are able to acoustically emulate human head and smallish acoustical instruments; not too large speakers and close to point source locating significantly above the floor, but not in the corners or flush mounted in the front wall.
But this compatibility turn worse if recording already has thin far field sound and reflections. Far field recordings work probably better with more directive speakers (or half space application) designed to transfer recorded sound to listener close to as is, without too much early reflections including floor. But voices recorded at near field could be unnaturally thick and too full-bodied which bothers especially with female voice and some acoustical instruments which sound quite thin at normal listening distance.
Woofer close to floor crossed at 300…500 Hz usually causes “base board sound”. Lower mid-range includes much fundamental frequencies so it’s a risk that different notes or harmonics of the same instrument or different instruments split to separate sources; bass from the floor and others higher, if single woofer or middle point (average elevation) of woofer group is too close to floor.
Balancing of speaker using floor gain for woofer could be more problematic than conventional design. Not so simple to estimate suitable level and response shape for woofer. Initial step could be equalizing power response flat below the lowest crossover point. Woofer close to floor generates also maximum vertical room resonance which causes variance in different rooms and listening spots.
I’m not sure about this, but I suspect that monopole woofer close to floor crossed significantly higher than Schroeder frequency could be one reason for designer’s gray hair. Radiating to half space only within limited range while higher frequencies spread “naturally” above Schroeder does not sound too logical imo.
Surprising or not, dipole woofer is able to avoid many/most of the issues and risks listed above. Dipole woofer or panel creates early reflection link with the room with help of rear radiation so the risk of “base board” and floorless floating sound is much smaller, ime. But it’s quite common that this link with room causes dip at upper bass without very careful positioning of the speakers.
I don’t know actual reasoning of commercial manufacturers, but personally I try to avoid locating single woofer too close to floor if I have a choice and the risk of negative side effects is high – knowing that high position is not perfect either.
This is my “short list”. Hopefully you can find those few words which link the story to woofer located close to floor.
Recording method i.e. type and location of microphone, distance to microphone, recording venue and possible post processing play significant role here especially with human voice but also with acoustical instruments which are not large.
Sound could be quite unnatural without adequate reflection link with room boundaries if recording does not include any reflections or recorded instruments were not in the same acoustical environment; real or processed. Instruments could sound floating almost like in anechoic; too far from ground or anything else natural for typical listening environments. This could also be stressing to listen, ime.
Reproduction with speakers could actually sound quite natural if voice was recorded close to mouth/instrument without much reflections/ambience and possible with some near field effects, and speakers are able to acoustically emulate human head and smallish acoustical instruments; not too large speakers and close to point source locating significantly above the floor, but not in the corners or flush mounted in the front wall.
But this compatibility turn worse if recording already has thin far field sound and reflections. Far field recordings work probably better with more directive speakers (or half space application) designed to transfer recorded sound to listener close to as is, without too much early reflections including floor. But voices recorded at near field could be unnaturally thick and too full-bodied which bothers especially with female voice and some acoustical instruments which sound quite thin at normal listening distance.
Woofer close to floor crossed at 300…500 Hz usually causes “base board sound”. Lower mid-range includes much fundamental frequencies so it’s a risk that different notes or harmonics of the same instrument or different instruments split to separate sources; bass from the floor and others higher, if single woofer or middle point (average elevation) of woofer group is too close to floor.
Balancing of speaker using floor gain for woofer could be more problematic than conventional design. Not so simple to estimate suitable level and response shape for woofer. Initial step could be equalizing power response flat below the lowest crossover point. Woofer close to floor generates also maximum vertical room resonance which causes variance in different rooms and listening spots.
I’m not sure about this, but I suspect that monopole woofer close to floor crossed significantly higher than Schroeder frequency could be one reason for designer’s gray hair. Radiating to half space only within limited range while higher frequencies spread “naturally” above Schroeder does not sound too logical imo.
Surprising or not, dipole woofer is able to avoid many/most of the issues and risks listed above. Dipole woofer or panel creates early reflection link with the room with help of rear radiation so the risk of “base board” and floorless floating sound is much smaller, ime. But it’s quite common that this link with room causes dip at upper bass without very careful positioning of the speakers.
I don’t know actual reasoning of commercial manufacturers, but personally I try to avoid locating single woofer too close to floor if I have a choice and the risk of negative side effects is high – knowing that high position is not perfect either.
This is my “short list”. Hopefully you can find those few words which link the story to woofer located close to floor.
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Because the room bounce is a conspiracy theory in audiophile world. It does not exist.
Room should be actually one of the most important factor for audio reproduction, but the acoustics section is by far the least popular forum in any audiophile forums in reality. This DIY forum is not the exception, and I don't know why...
Room should be actually one of the most important factor for audio reproduction, but the acoustics section is by far the least popular forum in any audiophile forums in reality. This DIY forum is not the exception, and I don't know why...
Yet you see most 3-way floor standing speakers could easily place the woofer lower on the baffle, but chooses not to do so for some reason...
Even most of Troels Gravesen's 3-way designs doesn't do so either.
So what gives? Only reason I can think of is that in the midst of all the other room effects, and general compromises that goes into a design, floor bounce isn't worth caring about
Totally agree!
Magico adhere to keeping their woofers close to floor, guessing with a crossover below 300hz. This is probably why they choose to go with fairly large midrange drivers.
Because if youve ever listened to a Sonus Faber 3 way, you'll know the problem they have. Small mid, crossed too low. No impact in the lower vocal range, v apparent with Johnny Cash etc