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In Reply to: RE: Which Maggie driver for mid-basses? posted by AkuAnkka on March 21, 2014 at 05:26:12
... those big panels you're trying to avoid function at their optimum in that vary 100hz-400hz bandwidth, IME. I'd be tempted to stack Maggie DWM's to optimally mate with your linear array of B&G:Neo8's ... with near similar driver height (for seamless presence) and similar push-pull planar-magnetic configuration (for seamless dynamics)... but, that would require series wiring dual DWMs per channel for an amplifier-friendly 8Ω impedance load (from a stock 4Ω) & surgically bypassing one of their stock internal (deduced ~1.82mh) inductors for a 400hz crossover (from a stock 200hz crossover). Just mount all DWM's for each channel within 4" (10cm) of each-other ... and, place each stacked DWM's 4inches away from its B&G linear-array for an effectively optimum crossover (prevent most multi-driver source interference patterns).
... just my 2¢♪ moderate Mart ♫ ☺ Planar Asylum
where speakers are thin & music isn't
Edits: 03/22/14 03/22/14Follow Ups:
Well I'm afraid that stack of DWM's is a bit too expensive solution for me.
But, regarding those larger bass drivers (1.x, 2.x, 3.x); would they really give any real benefit for the frequencies over 100hz, compared to smaller MMG/SMG-x drivers? I have thought that larger size just helps with the lowest basses.
P.S. : from what I understand , a vintage Magnepan configuration with perforated-steel magnetic pole-pieces in front & the classic Mylar diaphragms with traditional ( copper resembling ) round Milloxane coated aluminum wire aft... a slight consensus prefer those bass panels that way. It's my contention/opinion that the quasi-ribbon reduced T.H.D. design flipped the Maggies around. I wish my MG2.7.s had the pole-piece in front for my bass, & in stock configuration aft pole-piece for my Q.R. tweeter, & a two-sided push-pull midrange, but that price-point would be highly cost-prohibitive... especially from Magnepan ( who raise bang/buck engineering to an art ).
The pole-piece's accompanying perforated steel plate in front doubles as an acoustic low-pass filter ( as do the grill-cloth socks which can also double as modest damping of steel piece shimmer if doubled & they remain in direct contact ) for frequencies well above 2khz ( not intended to be generated by a Maggie bass-panel & if it is its mostly distortion ). Also, in my opinion, a fore pole-piece configuration sounds a tad more dynamic ( by what sounds like 3dB - 6dB to my ears ). I theorize ... since compressive waves are more audible to human ears ( see even-order versus odd-order THD ) which generate+propagate as the diaphragm thrusts forward at maximum acceleration ... while ideally occur at rest/zero position of the diaphragm/voice-coil are moving towards the magnets ( a stronger magnetic B-field ) which makes them increasingly efficient. Meanwhile, others speculate that the acoustic-filter lowers the noise-floor & that psycho-acoustically sounds more dynamic.
Also, heavy+rigid stands help bass panels sound even more dynamic. Issues to keep in mind if one wants to mate ( including P.R.a.T. ).
Last, but not least, by any means ( &, other pertinent pedantic rhetorical clichés ), wire your Bohlender-Graebener : Neo8's in series. They're already 5dB more efficient than the Maggies as it is & will require a series attenuating resistance to match S.P.L.s as it is ( e.g.: 4 Neo8's in series will equate to an approximate 15.2Ω ±0.4Ω load through the majority of the operational bandwidth & that equates to a 8.7Ω - 9.1Ω resistor ). Any parallel or series-parallel configuration will improve the linear-array's operational efficiency ( e.g.: four parallel Neo8's will produce 12dB gain from 92.5dB to 104.5dB at an amplifier-melting 0.9Ω minimal-impedance ... while a series-parallel circuit wiring configuration of the four Neo8 array has the same amplifier load as that of a single Neo8 driver impedance & boost the efficiency by 6dB for 98.5dB ). The good news is the Neo8's will employ a smaller capacitor ( thus, cheaper ), which also makes superior capacitors more affordable. It's impedance spike near 250hz coupled to a funky S.P.L. Bode plot will make the crossover challenging.
... just my 2¢♪ moderate Mart ♫ ☺ Planar Asylum
where speakers are thin & music isn't
Most Maggie bass panels suspension resonate ( mass of diaphragm interacts with tension of diaphram ) around 60hz. Planar-magnetic drivers don't initiate roll-off by back-EMF manifesting itself as an impedance spike as with conventional magneto-dynamic drivers ( mass of woofer-cone/tweeter-dome interacts with suspension-spider/surround ). Instead planar-magnetic drivers produces an SPL spike that proper positioning & back-wall reflections usually neutralizes.
Well, that's why/how bass-panels operate below 100hz... while they produce far less THD above 100hz ( well above resonance ). Maggies employ those tuning-dots / damping-pads to arrest THD near ~60hz resonance, but the drivers want to produce it.
... just my 2¢♪ moderate Mart ♫ ☺ Planar Asylum
where speakers are thin & music isn't
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