Mark Audio MAOP-7 122mm Magnetic Arc Oxidized Full Range Matched Pair
Overview
The MAOP process involves a chemical conversion where the cone material is converted into its crystalline oxide. The crystal grows both inward into the substrate and outward. As such the new coating is not a deposited coating but a part of the original structure that gives excellent adhesion.
The MAOP 7 driver can be used as an upgrade in the Frugel-Horn Mk3 cabinet kits.
Sold as matched pair
The MAOP series sits at the top of the Markaudio range and is aimed at audiophiles seeking the ultimate in full range speaker drivers. Due to the complex manufacturing and testing processes used to build these drivers, they are produced in small quantities. These drivers are popular in Asia, and hence when they are available, very few find their way this far West.
The Magnetic Arc Oxidisation Process is done at extremely high temperature in a flux bath that is prone to differential temperatures (hot/cold spots) which can warp the cones. The process is 10 times the cost of normal cone production, at least half are scrapped as it does render cones unusable if they are warped even slightly. The MAOP process involves a chemical conversion where the cone material is converted into its crystalline oxide. The crystal grows both inward into the substrate and outward. As such the new coating is not a deposited coating; it is part of the original structure which gives excellent adhesion. The large crystal structure provides excellent stiffness and resistance to damage. The crystalline structure also encapsulates microscopic voids. It is supposed that it is the blend of microscopic voids and stiff structure that lend the cone the audio properties of both the metal cone and the paper cone, accuracy and a listen-all-day quality.
After construction, each driver is individually measured in the anechoic chamber at the Markaudio factory and pair matched based on that data to within, 0.5% tolerance. Each pair is supplied with individual electrical and acoustic measurements.
Vented Box Alignment
0.25 cubic feet (7 liters)
1.5" diameter vent by 4" long
3dB down at 55Hz, 6dB down at 48Hz
MAOP7.2 vented box plans
MAOP7.2-slot-vent box plans
LS-MAOP7.2 BBC style box plans
MarkAudio Enclosure Plans
Parameters
Revc 5.4 Ohm
Fo 76.533 Hz
Sd 50.265 cm ²
Vas 3.915 Ltr
Cms 1.091m M/N
Mmd 3.758m Kg
Mms 3.963 g
BL 3.805 Txm
Qms 2.556
Qes 0.711
Qts 0.556
Levc 21.551 uH
No 0.239%
SPLo 85.799 dB
Pwr: 20 watts Nom
Xmax: 4.5mm (1 way)

Example of parameters included with each driver pair:


This is a miracle driver!
I came to MAOP-7 through Pluvia Seven HD. Pluvia performance vastly exceeded my expectations. Naturally I got curious whether and how MAOP-7 can improve on the already near-perfect Pluvia. The bottom line - MAOP-7 is BIG step above Pluvia. We all dream of speakers that could perform at the same level as good headphones. For me, the MAOP-7 sound is better than that of my Grado SR325 and Sennheiser 650HD. With different kinds of music, from pop to classic, the sound is so involving and enjoyable that I am having hard time ending my listening sessions.
The Micro Arc Oxidation Process creates a layer of very hard aluminum oxide (4 times harder than one created by anodizing) tightly bound to metal substrate. As a result, speaker cone gets sandwich structure in which speed of sound in the two layers is different. This disrupts standing waves at certain frequencies caused by border reflections. I suspect this is the key ingredient for the unbelievable sound of this driver. Thank you, Mark Fenlon, for this breakthrough - a point source full-range, no crossover needed speaker - a veritable holy grail of speaker design.
As described, MAOP-7 needs extended break-in to fully open. One limitation as a full range is that if one wants a single driver speaker, it will work well only at low listening levels because high excursion with higher level low frequencies will cause audible IM distortion. For higher levels it is necessary to cross out bass at 150-200 Hz and add an extra woofer, which could be Pluvia-7 or another 4" woofer.
My enclosure is 1 liter sealed box inside a 15 liter bass reflex cabinet with a 4" additional woofer. The MAOP-7 in this enclosure naturally rolls 2nd order at about 170 Hz, and acoustic suspension dominates cone's mechanical suspension. The woofer can be low-passed 2nd order Butterworth, or, preferably, bi-amped using a Class D sub amplifier.
Super Fantastic Full Range All-Stars
Without siting specifications or measurements, when it comes to my Heinsenfolg Bespoke Audio lifestyle speakers, it is all about voicing. The MAOPs have an incredibly natural sound. One that is detailed, without being too harsh or fatiguing. It is also warm, without being muddy. I find I can listen to these drivers for hours & hours, and never want to stop the listening session.
Yes, they're a bit pricier than my favorite go-to Pluvias, but for a special build, the MAOPs are absolutely worth the price for these sonically-matched pairs. Note: the MAOPs are priced as a pair, while other MarkAudio drivers are priced as singles.
This brings me to the presentation. The finish of the MAOP drivers are dead matte with no sheen what-so-ever. The color to my eye is a very neutral powdery greyish-white of the the lightest magnitude— definitely not super bright white, and not too dull grey either. I love the luxurious finish which is created by a complex manufacturing process worth reading about. They present very attractive, have a high end look, and match virtually any cabinet material because of their color neutrality.
I have truly come to love listening to these drivers everyday in my home, so they get my highest recommendation out of any full range driver coming anywhere close to their price range!
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