I've crossed a 3way in the notch region to effectively equalize and reduce the notch. Sounds horrible! maybe 3db correction is max to sound decent to avoid forcing more energy into the problem.
Horrible is referring to bass region while trying to reduce floor notch with crossover point. The crossover point has been raised well above the notch frequency, the notch is not corrected and now the bass sounds amazing!
Passive crossover, simulated, Measured. Box alignment studied, simulated measured in great length.
I've measured and listened to woofers mounted at floor level but not crossed to mid driver so not sure how this will work out.
Maybe its better to accept and live with the floor notch?
Horrible is referring to bass region while trying to reduce floor notch with crossover point. The crossover point has been raised well above the notch frequency, the notch is not corrected and now the bass sounds amazing!
Passive crossover, simulated, Measured. Box alignment studied, simulated measured in great length.
I've measured and listened to woofers mounted at floor level but not crossed to mid driver so not sure how this will work out.
Maybe its better to accept and live with the floor notch?
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I would look at the old Allison 1 for ideas.
Allison One Series Brochure (1978) pg5 | The Classic Speaker Pages
Rob
Allison One Series Brochure (1978) pg5 | The Classic Speaker Pages
Rob
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There could be many potential reasons why your loudspeaker "sounds horrible" (to you). It's difficult to say based on the limited information your provided.
How about describing how you designed the speaker and crossover, etc.?
Passive or active crossover, and details on that.
Did you make any measurements during the process?
Have you made a measurement of the "sounds horrible" response?
The more info you can provide, the better.
As we all know, there's a lot going on with the room response below 300hz. The floor notch crossover point boost has subjective phase distortion causing bass to sound bloated as it increases the existing phase issue caused by the reflection. For me, Part of great or amazing bass is when its not bloated. Is there a floor notch correction possible in the design of a speaker that will have minimal phase issues??? Will multiple subs give some correction to the floor reflection?? Room treatment can greatly improve most of the room boundaries but the the floor is more difficult to treat. What can be done with the floor?
- I think the thing about multiple subs is that the variation of multiple sources, even if its a symmetrical set up...the unique positions in the room result in several different phase patterns that sum into a more coherent image...instead of 1 sub that has an error at 50hz representing the whole bass region....you create several unique sources that have unique errors (not duplicating the 50hz error)... now, that 1 source, with the error at 50hz, represents a fraction of the summed signal and the error is masked by the other source that perform as intended in that area....I also look at this as an increase in direct energy....direct energy is less reflective of the room, and thus more accurate, so this aspect might help regarding the floor reflection....to apply multiple sub theory to the floor reflection you would place at multiple positions on the height parameter?....
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Below 200 or 300hz there is no "bounce" and no notches from the surfaces, room modes dominate the acoustics.
Room acoustics - Wikipedia
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Just measure the pulse response with a mike and you will see that all surfaces will cause destinct reflections arriving at the listening position.
When your distance changes or you use another room, the frequencies also differ, so it does not make sense to design this in,
Better to use acoustic measures like bass traps, selective damping, positioning of the speakers to suppress unwanted boosts (dips are not that nasty soundwise)
So all the info on Schroeder freq. is wrong? Does Earl tell you what freq. he is doing this for? Low freq produce standing waves, higher ones reflect. Did you read the link or are do you just throw out guesses?
Yea high freq reflections, no surprise, now try it with a 30hz signal. Do you understand what standing waves are?
What camplo writes there is mostly conjecture. Although he says so using words like "I think", it might not have been clear.Interesting. Thanks!
Putting multiple woofers in a vertical line does help with mitigating floor bounce some good simulation and experimentation here Modular active 3 way - work in progress
This is me spoon feeding you the first search result on this forum’s search function using “Gedlee” as author and “futon” as keyword:
From here, in response to a question about floor bounce in the 200-800Hz region.
A standing wave is a steady state description that simplifies the acoustic phenomenon. I do agree that below -say- 200Hz the importance of single reflections isn’t that big in auditory perception. But it’s not that they are not there. In as far as you could define the time-place-pressure variations close to a boundary as a ‘reflection’, you could also call it a ‘standing wave’
Sorry to say you are responding in a unpleasant way are you a troll?
If you cannot measure because of standing waves, maybe you try another signal source than a steady sine like MLS or chirps.
You better should read the book "Measuring Loudspeakers" by d'Appolito
You think that below the room Schroeder frequency that sound no longer follows wave-like behavior?
You ever heard of double-bass arrays?
We must remember what psycoacoustics of low frequencies does. We hear mostly the modal outcome, not direct sound.
With digital sound measuring programs like ARTA or REW it is easy to change measurement window time and distinguish first reflection null of first few milliseconds. Typiccal 500ms room response graph look different as well, it sort of simulates psychoacoustics.
In a room we can't eliminate first reflections, only diminish and try to avoid having several nulls near same freq, by placement of the speaker and listener.
With digital sound measuring programs like ARTA or REW it is easy to change measurement window time and distinguish first reflection null of first few milliseconds. Typiccal 500ms room response graph look different as well, it sort of simulates psychoacoustics.
In a room we can't eliminate first reflections, only diminish and try to avoid having several nulls near same freq, by placement of the speaker and listener.
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