frequency response curve of an omni-directional speaker

[skyfly]

Falcon Lab in Japan makes onmidirectional speakers. High is rolled off from the factory.

Falcon Lab
Model 4401

 

[A800]

Looks like they had to decrease the airiness.

 

[Zvu]

Well, they had to. Given that it is omni directional loudspeaker, its power response and room curve does not have gradual downward tilt as monopole or dipole loudspeakers - which makes them sound natural.

If omni would be made flat, that would definitely translate to very bright sound in room. Maybe acceptable outdoors.

 

[JustIntonation]

Well, they had to. Given that it is omni directional loudspeaker, its power response and room curve does not have gradual downward tilt as monopole or dipole loudspeakers - which makes them sound natural.

If omni would be made flat, that would definitely translate to very bright sound in room. Maybe acceptable outdoors.

It would not in most rooms.
The early direct reflections would sound bright if from an untreated surface (like a bare floor or wall, best to absorb early reflections anyhow) but the later reflections / reverb would naturally get a downward slope. It's the nature of reverb.
I've been experimenting with omnidirectional speakers lately and the result is not bright at all. The result is a huge soundstage with depth and realism.

 

[Zvu]

It would not in most rooms.
The early direct reflections would sound bright if from an untreated surface (like a bare floor or wall, best to absorb early reflections anyhow) but the later reflections / reverb would naturally get a downward slope. It's the nature of reverb.
I've been experimenting with omnidirectional speakers lately and the result is not bright at all. The result is a huge soundstage with depth and realism.

Subjective impression of brightness for two of us may differ.

Do provide us with spinorama measurements and PIR. Then we can inspect if your experiments are true omni at all frequencies looking at sound power in relation to on axis.

Axiom Audio makes true omnidirectional loudspeakers. Here is Listening window and Sound power on the same graph. You'll notice it is tilted down - nice constant slope of 5dB from 200-10000Hz.

 

[JustIntonation]

Subjective impression of brightness for two of us may differ.

Do provide us with spinorama measurements and PIR. Then we can inspect if your experiments are true omni at all frequencies looking at sound power in relation to on axis.

Axiom Audio makes true omnidirectional loudspeakers. Here is Listening window and Sound power on the same graph. You'll notice it is tilted down - nice constant slope of 5dB from 200-10000Hz.

Read the graph you posted. It says "Listening Window". Not on-axis frequency response which I assume is fairly flat (other than some errors due to their design of using too narrow a baffle and too deep).
That speaker is not fully omnidirectional, it is a near-omnidirectional bipole.
Btw a wide undeep baffle will work better, for instance the Mirage M-1.
edit: and forgot to mention, what's up with that two tweeter thing (on front baffle) with the Axiom? There are good reasons why not to do that kind of thing.

 

[Zvu]

Read the graph you posted. It says "Listening Window". Not on-axis ...

Read the graph you posted. It says "Listening Window". Not on-axis frequency response which I assume is fairly flat (other than some errors due to their design of using too narrow a baffle and too deep).
That speaker is not fully omnidirectional, it is a near-omnidirectional bipole.
Btw a wide undeep baffle will work better, for instance the Mirage M-1.
edit: and forgot to mention, what's up with that two tweeter thing (on front baffle) with the Axiom? There are good reasons why not to do that kind of thing.

If a loudspeaker you've experimented with is truly omnidirectional in horizontal plane, every measuring/listening axis is ON-axis and listening window will look the same as "on axis".

 

[JustIntonation]

If a loudspeaker you've experimented with is truly omnidirectional in horizontal plane, every measuring/listening axis is ON-axis and listening window will look the same as "on axis".

If it were truly omni in both the horizontal and vertical plane, then yes.
But as I wrote, the Axiom speakers are not truly omni. They're regular drivers on a regular baffle, the only difference is that there's mid and tweeter drivers on the back as well making it a bipole speaker which has its own radiating pattern.
The listening window is certainly not the same as the on-axis response with this speaker. Instead the listening window will be tilted down relative to the on-axis response.

Btw, not saying the bipole way of getting a near-omni design is bad, I think it's a great way to do it, perhaps the best way even (though I think the design can be optimized a lot better than Axiom did).
You can also easily do a rough test of the bipole effect at home. Simply take two regular speakers, place them back to back and play mono music through them. Place a 6dB/oct shelving EQ cut in the bass/lower mids (depending on speakers used) to compensate for the omni bass summing of the rear speaker so the speaker is flat (removing the baffle step compensation in effect). And enjoy mono bipole sound. (place the speakers free standing).
If you setup the above test in software and level match then you can a/b with a click between front speaker monopole and front+back dipole. Though if you set this test up properly it comes with a risk, you may never want to go back to monopole again. Especially if you do the test with 4 speakers and hear stereo bipole Btw, you may want to listen a bit closer than usual as you'll have plenty of soundstage in the mid-field or even nearfield with bipole.