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Multi-Way Conventional loudspeakers with crossovers

Why is floor bounce mostly ignored in commercial speakers??
Why is floor bounce mostly ignored in commercial speakers??
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Old 3rd December 2019, 02:08 PM   #21
Defo is offline Defo  Norway
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Quote:
Originally Posted by boswald View Post
...crossed at 300, so your idea is in the ballpark
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.
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Old 3rd December 2019, 06:46 PM   #22
boswald is offline boswald  United States
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Why is floor bounce mostly ignored in commercial speakers??
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.

Last edited by boswald; 3rd December 2019 at 06:49 PM.
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Old 3rd December 2019, 08:20 PM   #23
Defo is offline Defo  Norway
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Originally Posted by boswald View Post
...The only bounce cancellations to avoid here are for the midrange...
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
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Old 4th December 2019, 12:10 AM   #24
ScottG is offline ScottG  United States
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Gradient has substantive pressure loss (at greater than 60 degrees) above 300 Hz due to the "leaky" enclosure of the sphere.

That portion that does NOT have pressure loss - is coupled to the floor.

ie. it's NOT a typical example.
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Old 4th December 2019, 01:05 AM   #25
boswald is offline boswald  United States
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Why is floor bounce mostly ignored in commercial speakers??
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)].

Last edited by boswald; 4th December 2019 at 01:21 AM.
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Old 4th December 2019, 01:51 AM   #26
AllenB is online now AllenB  Australia
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Zest is a cooking term too. Mmm, speakers you can eat, and a nice glass of ferrofluid.
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Old 4th December 2019, 02:08 AM   #27
ScottG is offline ScottG  United States
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..and a nice glass of ferrofluid.
Seek help. Now.
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Old 4th December 2019, 01:36 PM   #28
Kay Pirinha is offline Kay Pirinha  Germany
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Quote:
Originally Posted by Defo View Post
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.

...and some 200 cm beneath the ceiling, I assume? So your room needs to be four meters high, at least?
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Old 4th December 2019, 01:51 PM   #29
picowallspeaker is offline picowallspeaker  Italy
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Why is ceiling height mostly ignored in commercial houses?
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Old 4th December 2019, 02:21 PM   #30
Kay Pirinha is offline Kay Pirinha  Germany
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Of course. So let's assume that there are more people who have carpets laying on their floors than those with carpets glued to the ceilings. Hence the question has to be redirected to ceiling bouncing?
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