Measured monopole and dipole room responses

[gedlee]

I am not sure that I can explain. Its interesting data and results, but I am not sure that I do know what is going on.

I certainly would not consider times on the order of 20 us as relavent, or do you mean 2 ms?

My point is simply home much the room changes any and all characteristics of the source at LFs. Free field characteristics of a LF source just do not have much relavance to its use in a real room.

[Elias]

Originally Posted by soundaatma

In post #444, the second graph from the bottom titled "Raw Impulse responses Monopole top, Dipole bottom" was actually a bit confusing to me. For the monopole the region from the impulse upto .02ms looks crowded, but for the dipole this is clean. However after .02ms there is pronounced ringing in the dipole response; much more than the monopole response.

Does this mean that the dipole is cleaner before .02ms compared to the monopole. However after .02ms the monopole is cleaner....is this the reflected soundfield because of room reverberation.....but if the room is the same, so should be the reverberation time. In any case after .02ms why is there more overhang in the room for the dipole than the monopole.
Please explain. Thanks.Actually this is only comparative graph which is distinctly different b/w the monopole and dipole.

We don't know anything about Barleywater's system so hard to draw conclusions.

It looks like though that the time axis is in seconds. Then the dipole resonance at 130 Hz would match the time scale ringing.

I think the 130 Hz peak can simply be a H-frame cavity resonance.


- Elias

[john k...]

I don't understand how the corrected impulses in post 444 appear to be perfectly symmetrical. The system would have to be linear phase as well as flat response for that to happen. even assuming the unequalized woofer is minimum phase, amplitude correction would still leave it as a minimum phase band pass device which should show a casual impulse with some post peak oscillation. It doesn't make sense to me.

[Elias]

To me it looks like the impulse responses were inversed to approach Dirac delta function. Some nonidealities remain like the ringing due to bandwidth limitations including AD conterter antialias filtering.

[soundaatma]

Originally Posted by gedlee

I am not sure that I can explain. Its interesting data and results, but I am not sure that I do know what is going on.

I certainly would not consider times on the order of 20 us as relavent, or do you mean 2 ms?

My point is simply home much the room changes any and all characteristics of the source at LFs. Free field characteristics of a LF source just do not have much relavance to its use in a real room.

Just reading from the graph, the reading in the x-axis is ".02" and the unit labelled as "hms". I am not sure if this means .02 seconds or 2 milliseconds OR .02 milliseconds
The room responses after equalization is eerily similar with NO difference

[Wavebourn]

Originally Posted by soundaatma

Even with the same diameter drivers, equalised to same LF extension, listened at moderate SPL, to even nearfield (2-3 Meters) there is that slight overhang in sealed units that makes it sound like a "speaker" which is not apparent in a dipole(H or Uframe) making it sound that last bit different ... or "natural'. No scientific logic/evidence "yet" discovered....Wonder if it is the lower group delay in the dipole which is small yet audible

Reverberation does not need to be "scientifically re-discovered". When you hear it from around, coming from different directions, it is reverberation that gives you an information about the space in which the music sounds. But when you hear it from some point source it is "speaker" sounding, while room reverberation still exists, and sounds like "Speaker In The Room". You hear 2 different volumes, one (room) from around as reverberation, another from speaker like "speaker sound". But if to blend them together in space around head and ears it sounds more natural. It is exactly what dipoles do, and why they sound more natural.

[gedlee]

Originally Posted by john k...

I don't understand how the corrected impulses in post 444 appear to be perfectly symmetrical. The system would have to be linear phase as well as flat response for that to happen. even assuming the unequalized woofer is minimum phase, amplitude correction would still leave it as a minimum phase band pass device which should show a casual impulse with some post peak oscillation. It doesn't make sense to me.

Just as bad is what appears to be some DC content in the corrected impulses. That's not possible for an acoustic pressure response, especially for a dipole. Something isn't right.

[soundaatma]

Originally Posted by Wavebourn

But if to blend them together in space around head and ears it sounds more natural. It is exactly what dipoles do, and why they sound more natural.

This is what this thread is all about...What EXACTLY (and how ) do dipoles do to make them sound more natural ( at least to some...who go to great extents at higher costs to expand their dipole systems and never come back to monopoles again).

[gedlee]

Originally Posted by soundaatma

This is what this thread is all about...What EXACTLY (and how ) do dipoles do to make them sound more natural ( at least to some...who go to great extents at higher costs to expand their dipole systems and never come back to monopoles again).

Let me just say here that the majority of my customers last speakers were dipoles, so your claim is simply not true, its just your perception.

[Wavebourn]

Originally Posted by soundaatma

This is what this thread is all about...What EXACTLY (and how ) do dipoles do to make them sound more natural ( at least to some...who go to great extents at higher costs to expand their dipole systems and never come back to monopoles again).

It is one half of the truth: dipoles in untreated rooms sound as if more natural. That does not mean that they more naturally reproduce records, so room treatments are applied. But if to treat the room this advantage goes away, and distortions caused by higher excursion start dominating.