Two down, a few more to go...
Keep up the good work
/Mostly
Two down, a few more to go...
Keep up the good work
/Mostly
Hi Don,
Interestingly, but "old school" 43xx series monitors , owing to lenses used, had quite large horizontal dispersion...
for me, really unexpected was M2, quite large vertical dispersion (120deg) too , and I can imagine that the floor reflection can produce some troubles.
Some rumors emphasize that the need for sub-woofer is something well-come too.
May be one day each loudspeaker would be offered separately with its own DSP and power amplifier, so the customer can decide what would be his need, but in such situations, we are not talking about the loudspeaker box, but a kind of audio reproduction system.
regards
Ivica
Hi Ivica,
The lens used on all of the 43xx series was actually quite narrow in dispersion with an 80 x 40 coverage and I suspect that it would not be as uniform within its range as the M2 waveguide is within its range.
For home theatre - sure. For music - not that I can tell. The M2 has a more extended bass response than E2 which is not what I would consider a bass shy speaker.
The transition to that day is well underway. Speaker design has evolved to the point where a systems approach forms the basic design principle. The primary design concern is the sound that reaches the ear that not the sound that leaves a box. This means that transducers, crossovers, enclosures, amplification, DSP, room response and psycho acoustics are all wrapped up into a holistic design process. Physical integration is just the next step that is already widely in place in the pro sound world.
Regards
Don McRitchie
Even if they went down to DC an extra sub or two helps tame the nodes and the antinodes.
"Originally Posted by Don McRitchie View Post
In contrast, the M2's tackle the destructive interference issue in a manner that is 180 degrees opposite in approach. Instead of trying to limit sound dispersion and decrease the amount of sonic energy that will reflect off of a boundary, the M2' are designed for a very wide 120 degree dispersion at all frequencies.
The intent is to provide as uniform and wide a sound-field as possible so that destructive interference affects a smaller overall proportion of the overall sound-field. "
Hi Don,
Can you walk us through the above as it seems to defy conventional wisdom.
If you focus on what was meant by 'destructive' it's possible to see the intent as I -think- I understand it...
but sure, a walkthrough would be great
Crowns only. I can't attribute any sonic characteristics to the amps either positive or negative since I could not isolate their contribution to the overall sound. Certainly the DSP features of the Crowns played a significant role in the overall response. Interestingly, the Crowns were located in a rack placed just outside of the room in a hallway. Others have pointed out the potential for fan noise in the Crowns and I'm guessing that's why they were out of the room. I couldn't hear any fan noise at idle when I walked out of the room, but I have no idea on the degree of audibility when they're working hard.
Regards
Don McRitchie
Hi Ian,
I’ll try. I’m the first to admit that my background in audio is not technical so I could easily be misconstruing what has been relayed to me. However the following is my understanding by way of an example.
Assume a 4m x 5m area is marked out in free space. Place two M2’s at one end of this area and measure the response at multiple points within the area. Now take two somewhat directional JBL monitors, like the 70's four-ways, and measure the response at multiple points within the area. They will be significantly less uniform than the M2's.
The M2's have the most uniform frequency response across the widest dispersion of any horn based JBL speaker. In particular, the LF directivity at the cross-over is a near exact match to the horn which maintains its wide directivity at a near constant throughout its range. In contrast, the classic four-ways have a near omni directional LF, a somewhat directional mid bass, a very directional midrange and a wide dispersion HF.
Now add room boundaries around the 4m x 5m area, and again measure the response across the room for both speakers. The response of both will suffer due to destructive interference. However, the four-ways will have the poorer overall room response given their significantly lower starting point in overall soundfield uniformity. JBL asserts that this greater overall room uniformity results in superior overall sound. This is JBLPro’s current design philosophy for monitors that continues on the LSR (Linear Spatial Response) approach that has been in use for over a decade.
Regards
Don McRitchie
"Destructive" being that which contributes to a non-uniform room response,
with uneven spatial characteristics over frequency being part of the set of
addressed issues in this design. Reflections happen Thanks Don.
Hi Don,
1.
it would be nice if You can support us about the measurements that would be a kind of confirmation of Yours words about the M2 horizontal and vertical dispersion characteristics. So it can be easy to compare with the "old school" models.
2.
As used 15-inc bass transducer (2216) I can guess that it behaves (in the polar response) as almost all the other JBL 15" LF ribbed-cone transducers, so starts "beaming" over 1kHz.
3.
I can expect a kind of interference between LH and HF section in VERTICAL plane as the LH and HF drivers are spaced about 17-inch (43cm) center-to-center. Such "problem" has been analyzed in some JBL papers too. Owing to the DSP supported drivers drive the horn length can be compensated, but even then the problem would persist.
Regards
ivica
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