Evidence-based Speaker Designs

[QMuse]

It tends to basically act as a reflector in the frequency range of the primary null.

In that case doesn't it also happens with human voices and other natural sounds occuring in room as well? I can't really see how this theory that we are simply used to such things can be wrong. Samt thing as with group delays caused by wall reflections - sure they are there but we are simply used to them and they form specific in-room acoustic ambient. I guess we are all aware that our voices sound differently in different rooms.

 

[tuga]

What's less clear is the audibility of this floor bounce null.

Toole believes it is inaudible (although this is based mostly on a personal anecdote).

Bech simulated first reflections in an anechoic chamber and found that the perceived timbre of the signal was affected significantly by (simulated) floor bounce, but only above 500Hz, i.e. higher in frequency than the first (and widest) null tends to be, and in a frequency range more easily absorbed - probably not by a rug, but by a thick-ish layer of rockwool, for example.

Others insist that floor bounce is a natural phenomenon and that elimination of it is detrimental to sound quality as it creates an "unnatural" sound field. I haven't seen any scientific data supporting this view.

This last claim is absurd.
You can't transfer the qualities of live sound to those of reproduced sound. If the mic (like the listener's ear) picks up floor cancellation, should you add an extra layer of cancellation at the reproduction end?
People obssess with flat on- and off-axis response in the upper mids and treble where sound is mostly composed of harmonics and suddenly a dip in the very core of music's fundamental frequencies doesn't matter?


If the cancellation falls in the 250-400Hz region (associated with "warmth" and "fullness" of sound) it'll kill the sound of many acoustic instruments and also vocals.

It may help with cinema because too much tends to "muddy" or "congest" the sound and offers of a "tight", "fast", "dry" (yet unnatural) bass tend to enjoy it. Distortion may be good in some instances and for some people.

 

[QMuse]

People obssess with flat on- and off-axis response in the upper mids and treble where sound is mostly composed of harmonics and suddenly a dip in the very core of music's fundamental frequencies doesn't matter?

Sounds are never, and hear I mean literally never, composed mainly of harmonics.

 

[andreasmaaan]

This last claim is absurd.
You can't transfer the qualities of live sound to those of reproduced sound. If the mic (like the listener's ear) picks up floor cancellation, should you add an extra layer of cancellation at the reproduction end?
People obssess with flat on- and off-axis response in the upper mids and treble where sound is mostly composed of harmonics and suddenly a dip in the very core of music's fundamental frequencies doesn't matter?

If the cancellation falls in the 250-400Hz region (associated with "warmth" and "fullness" of sound) it'll kill the sound of many acoustic instruments and also vocals.

My inclination is to agree with you but, as usual, I don't share your enthusiasm for reaching categorical conclusions based on nothing but speculation and hypothesising, with no actual data.

It may help with cinema because too much tends to "muddy" or "congest" the sound and offers of a "tight", "fast", "dry" (yet unnatural) bass tend to enjoy it. Distortion may be good in some instances and for some people.

This is just making it up as you go along, IMHO

 

[andreasmaaan]

In that case doesn't it also happens with human voices and other natural sounds occuring in room as well? I can't really see how this theory that we are simply used to such things can be wrong. Samt thing as with group delays caused by wall reflections - sure they are there but we are simply used to them and they form specific in-room acoustic ambient. I guess we are all aware that our voices sound differently in different rooms.

Yes, but our voices don't sound equally good in different rooms.

If someone in your household can sing and is willing to indulge you, try taking them around the house and listening to their singing in different positions in different rooms. Try putting them near the floor, near the walls, in small reflective toilets/bathrooms, in the clothes cupboard, etc. etc. The perceived sound quality is not going to remain constant.

 

[tuga]

Sounds are never, and hear I mean literally never, composed mainly of harmonics.

Download Audacity and put a broad dip at around 350Hz in a track you know well.
It's easy to try.

 

[QMuse]

Yes, but our voices don't sound equally good in different rooms.

Hmm, I think you're walking on thin ice here. For example, many can argue that their voices sound best in bathrooms.

 

[andreasmaaan]

Hmm, I think you're walking on thin ice here. For example, many can argue that their voices sound best in bathrooms.

I didn't say it wouldn't

 

[tuga]

Bill Evans "Waltz for Debby"

 

[QMuse]

I didn't say it wouldn't

But one can argue that bathrooms are pretty much the opposite of professional recording/mastering studios.

 

[tuga]

Tracy Chapman "Fast Car"

 

[andreasmaaan]

But one can argue that bathrooms are pretty much the opposite of professional recording/mastering studios.

And absorbing the floor bounce is pretty much the opposite of a live musical performance. You see where I'm heading...?

 

[tuga]

Beethoven Symphony No. 9 4th movement:

 

[andreasmaaan]

Beethoven Symphony No. 9 4th movement:

@tuga what are these spectra demonstrating?

 

[QMuse]

And absorbing the floor bounce is pretty much the opposite of a live musical performance. You see where I'm heading...?

Just wait untill "kill all the reflections" crowd wakes up and jumps on you!

 

[tuga]

This is just making it up as you go along, IMHO

No, it's how sound engineers and producers fabricate recordings. Studio mixes are heavily manipulated.

A few sources:

http://alexiy.nl/eq/

https://www.teachmeaudio.com/mixing/techniques/audio-spectrum

 

[QMuse]

@tuga what are these spectra demonstrating?

Probably that harmonics dominate the fundamental tone.

 

[andreasmaaan]

No, it's how sound engineers and producers fabricate recordings. Studio mixes are heavily manipulated.

A few sources:

http://alexiy.nl/eq/

https://www.teachmeaudio.com/mixing/techniques/audio-spectrum

The relevant part of your post I was responding to was (in bold):

It may help with cinema because too much tends to "muddy" or "congest" the sound and offers of a "tight", "fast", "dry" (yet unnatural) bass tend to enjoy it.

 

[tuga]

@tuga what are these spectra demonstrating?

The range where fundamentals live.

 

[Frank Dernie]

Others insist that floor bounce is a natural phenomenon and that elimination of it is detrimental to sound quality as it results in an "unnatural" listening experience. I haven't seen any scientific data supporting this view.

It would be interesting to see some research on this sort of thing.
There must be some sort of way we become familiar with the room acoustically since IME listening to the output of a microphone sounds much different to me than putting my head where the microphone is.
I have always explained this to myself in that the microphone is unaware but i am not.
A cello sounds like a cello here but if one records it in different places in the room each recording sounds different, sometimes surprisingly so.
This means any room compensation calculated from microphone signals may well be compensating for differences a person won't notice. Or maybe not!