If after hearing this improvement you still wish to cancel the 125 Hz hump even further, you can still do this by connecting the subwoofer in the opposite relative phase to the main 2 way system, i.e. by connecting the subwoofer correctly as indicated, red cable to red terminal, so it is the opposite of the backwards connection (red cable to black terminal) you have just made to the main 2 way system.
     Fifth, the coherence problem, common to all speakers with higher order crossovers, was exacerbated in this Osborn because the tweeter, the driver in this system that already sounded a little too hard, direct, and bright, was color coded to be connected in correct absolute phase polarity, which inherently is more direct and harder sounding, whereas the softer (more neutral) sounding driver, the woofer/midrange, was color coded to be connected in inverted absolute phase polarity, which inherently is softer, more phantom sounding. In short, the harder sounding driver was connected in the harder sounding polarity, while the softer sounding driver was connected in the softer sounding polarity. Thus this connection choice magnified and aggravated the incoherence and inconsistency between the two drivers.
     By deliberately disobeying the color codes and making the opposite connection choice, we instead minimize the incoherence and inconsistency. We bring the two drivers much closer together in sonic quality by the simple expedient of assigning the softer sounding connection (inverted polarity) to the harder sounding driver in this system (the tweeter), and the harder sounding connection (correct polarity) to the softer sounding driver (the woofer/midrange). This makes this Osborn speaker sound much more coherent, since the two drivers are now much closer to each other in sonic quality. The midrange portion of a musical note now sounds much closer in quality to the treble overtones of the same note. Remember, incidentally, that we must assign inverted polarity to one driver or the other; since this is a second order crossover, we can't assign correct absolute phase polarity to both drivers (unless we want a frequency response hump at the 3500 Hz crossover point).
     This simple trick, connecting the terminals backwards, makes all the above improvements, and takes this Osborn speaker that extra crucial 9%, from 90% to 99%, transforming it from a great large speaker with some flaws into a true Reference that we or you could be enthralled with, without reservation, for years. It makes this speaker even more tonally neutral, more integrated, more seamless, more consistent, and more coherent, since its tonal quality is now more equal for the two main drivers.
     The Grand Monument Reference version, reviewed here, has some special features that set it apart from the regular version of the Monument. The cabinet walls are lined with a lead plus felt sandwich, which contributes both mass and inertness. The cabinet panels of any speaker system, especially a large one, can radiate huge amounts of unwanted blurring sonic energy, which artificially colors and blurs the true musical information that the drivers themselves are radiating. The very best speaker systems go to extraordinary lengths to deaden these cabinet walls, so they don't vibrate and radiate unwanted energy. The lead and felt sheets lining the walls of the Grand Reference surely deserve credit for the Grand Reference's outstanding transparency and low coloration. The regular Monument has a similar cabinet but omits the lead lining, so sonically there should be a little more wood cabinet coloration.
          The Grand Reference also features that ridiculously expensive Audiom TLR tweeter with the giant magnet, which gives it such speed and transparency. In contrast, the regular Monument employs a more sensibly priced Audiom titanium inverted dome tweeter (said to be essentially the same model used in the Wilson Grand Slamm). Thus, if you just can't squeeze $19,975 out of your budget for a Grand Reference, you can still get similar sonic performance for $14,500 from the regular Monument. However, we suggest, if you are spending this kind of serious money for a speaker system, that you go for the gold and get the Grand Monument Reference.
     The Osborn Grand Monument Reference is easily one of the very best large speaker systems you can buy, with very strong intrinsic sonic capabilities across the board. Its price makes it the most attractive bargain among these great large speaker systems. Adding our easy trick mod (at zero cost) maximizes its sonic strengths and almost eliminates its few weaknesses, getting the most out of this speaker's potential, and taking it from 90% to 99% of its promise. Hearty congratulations to designer Greg Osborn. Everyone deserves to hear what this speaker can do. If your local dealer doesn't carry this speaker, you can visit the Osborn website at www.osbornloudspeakers.com.au.

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