Ultimate OB GALLERY

[markus76]

Originally Posted by Helmuth

Due the wave length and path traveled the reflection will ad in opposite phase

...only for certain frequencies. The very same is true for a dipole. Now consider that we're talking about wavelengths that don't produce "reflections" because the room is small compared to the wavelength.

[Helmuth]

Originally Posted by markus76

...only for certain frequencies. The very same is true for a dipole. Now consider that we're talking about wavelengths that don't produce "reflections" because the room is small compared to the wavelength.

Witch wave length are you thinking of?

[markus76]

Originally Posted by Helmuth

Witch wave length are you thinking of?

All frequencies below and around the Schröder frequency.

[Helmuth]

Originally Posted by markus76

All frequencies below and around the Schröder frequency.

that would be below 200-300Hz with what I measure and hear it doesn't make sense what you say there.
So your making a faulty assumption somehow and I do not know why.

It also would mean the OB doesn't make sound below the schroder frequency.

[markus76]

Originally Posted by Helmuth

that would be below 200-300Hz with what I measure and hear it doesn't make sense what you say there.
So your making a faulty assumption somehow and I do not know why.

It also would mean the OB doesn't make sound below the schroder frequency.

Why would an open baffle not make any sound below the Schröder frequency? Either your or my understanding of sound propagation in air is false.

[gainphile]

Markus do you have pics to share? This is a gallery thread

[gainphile]

Nice recently built Nao Note:

NaO Note preview

[mayhem13]

Great build...ROUGH room for sure. Ouch!

[john k...]

Originally Posted by rob g

I do not know what he is talking about. Usually people worry about the out of phase wave from dipole not monopole. Even that is not a major concern in real rooms:

From Linkwitz lab's:
"Often concern is expressed over the fact that the rear radiation from a dipole is out of phase with the front radiation, and that thus any sound reflected from a wall behind the speaker would cancel sound coming from the front of the speaker. Cancellation can only occur when direct and reflected sounds are exactly of opposite phase (180 degrees) and of the same strength. Since direct and reflected sounds travel paths of different length, they undergo different amounts of phase shift. Thus, the phase and magnitude conditions for cancellation are given only at certain frequencies, if at all. At some other frequencies direct and reflected sounds will add. The same also applies to a monopole speaker in front of a wall. The only difference is in the frequencies for which addition and subtraction occur. The best remedy is to move the speaker away from the wall, or to make the wall as sound absorptive or diffusive as possible"

SL is talking in generalities here, as he often does, and about higher frequencies. The behavior of monopole, dipole and cardioids, due to the reflection from the wall behind the speaker is discussed HERE. And the real situation is more complicated due to room modes.

[lenta]

Originally Posted by mayhem13

Great build...ROUGH room for sure. Ouch!

I agree, room is untreated, and with worst floor material possible. I imagine how uncomfortable acoustics is. Dips an peaks in this room definetly can reach +-10db not onnly in bass.