AvsB Maximum Acoustic Power

[ro9397]

For the range of 130 Hz-2 kHz how does maximum acoustic power between four 5.8cm square full range drivers vs. one Dynaudio 17WLQ 170mm Esotec midbass? Both drivers are reasonably flat to 2 kHz. Specs below:

Le, Inductance, mH
5.8cm square: 0.137 +/-10%
17cm round: 0.19 @ 10kHz

BL, Force factor, Tm
5.8cm square: 3.87
17cm round: 6.0

Fs, Resonance frequency, Hz
5.8cm square: 148 +/-20%
17cm round: 40

Drv, Voice coil diameter, mm
5.8cm square: 25.4
17cm round: 75

Mms, Moving mass, g
5.8cm square: 1.68
17cm round: 15

Cms, Compliance, mm N-1
5.8cm square: 0.70
17cm round: N/A

Rms, Suspension Loss, Ns m-1
5.8cm square: 0.49
17cm round: N/A

Xmax, Maximum coil excursion p-p, mm
5.8 square: 7.0
17cm round: 17.0

Sd, Effective piston area, cm-square
5.8 square: 17.2 (x4 = 69)
17cm round: 120

VAS, Equivalent volume, L
5.8 square: 0.29
17cm round: 22

Qms, Mechanical quality factor, Qms
5.8 square: 3.18
17cm round: 1.8

Qes, Electrical quality factor, Qes
5.8 square: 0.83
17cm round: 0.5

Qts, Total quality factor, Qts
5.8 square: 0.66
17cm round: 0.4

Sens, Sensitivity, dB/W/M
5.8cm square: 83 (x4 = 89)
17cm round: 86

Continuous power handling, (weighted pink noise), W
5.8cm square: 12 (TBC)
17cm round: >130 (IEC)

Burst power handling, (weighted pink noise), W
5.8cm square: >24 (TBC)
17cm round: >1000 (10ms)

Thanks!

[AllenB]

I notice that the SD and Xmax specs indicate that the Dynaudio can move just over 4 times the air than four of the others.

[DBMandrake]

You also won't be wanting to operate 4x small drivers together as high as 2Khz, as lobing will be a serious issue at frequencies where they're more than half a wavelength apart.

[AndrewT]

Sens, Sensitivity, dB/W/M
5.8cm square: 83 (x4 = 89)

only holds true over a restricted frequency band.
Post3 mentions one of those frequency band problems.

[ro9397]

Originally Posted by DBMandrake

You also won't be wanting to operate 4x small drivers together as high as 2Khz, as lobing will be a serious issue at frequencies where they're more than half a wavelength apart.

Thanks for all your input, especially above!

I'm not well versed at this, so I fully expect and request those with more moxie highlight the errors of this plan...please, by all means, fire away!

I'm thinking about siting the four mids similar to the four 1" domes in this James Loudspeaker 812BE quad-tweeter array:



Where James centrally locates a phase plug, I would site a planar tweeter (H x W: 3.4 x 2.1") among the four 5.8mm square full range drivers. I only mentioned 2 kHz earlier because that's the range of the upper limit for the 17WLQ. The full range/tweeter crossover is likely closer to 6 kHz, more suitable for the planar tweeter, plus hopefully, complementary with the full range array. (BTW, the tweeter has a special waveguide to approximate a hemispherical radiation pattern in the horizontal plane).

My sum total physical experience with the 812BE is zero. IIRC MSRP is $16k/pr. HERE's the 812BE link for anyone desiring more info. Two apparently reliable pro installers generally recommend James. I discovered the array perusing the James site. Also, two fairly brilliant designers independently recommended such an array, one of them about 35 years ago, one a much younger designer with an excellent track record of great sounding speakers with which I'm intimately familiar.

Let's presume the four tweeters above cover from about 3 kHz and up.

I presume either A or B applies below to the above array:
A) The array provides a good, wide, pleasing, hemispherical radiation pattern and solves the aforementioned negative lobbing issue.
B) Is overall a failed design to properly site multiple drivers physically separated over 1/2 the shared frequencies.

As I mentioned, please do indeed fire (no pun intended) away!

[ro9397]

Originally Posted by AllenB

I notice that the SD and Xmax specs indicate that the Dynaudio can move just over 4 times the air than four of the others.

Thank you!

To what extent, if at all, is the above limitation affected by the 130 Hz cutoff?

[AllenB]

I would assume that you'd cross (EQ) both cases to have the same response, so at the low end I see it as simply moving air, so to speak.