Aurum Cantus G2Si Main / Stereo Speaker

There's a lot of hype in the audio world.  If someone isn't trying to sell you a $300 cable, they're hawking pieces of plastic meant to look like speakers but with differences you can hear.  The Aurum Cantus G2Si represents the other side: hi-end sound at a manageable price.

I should probably qualify the statement.  Obviously, "manageable prices" are different to different people.  Some folks like to buy the whole system for a few hundred dollars.  To those people, a ribbon tweeter is not in the cards.  The fact that Aurum Cantus's G1 costs $500 per tweeter is probably not going to matter.  The fact that this tweeter represents an 80% discount from the world of the G1 probably means little.  If you're just looking to just get in and get out, for the lowest price possible, buy used and buy something else.

I'm the kind of person who would be drawn to this tweeter.  When I first looked at the home-theater market, I was stunned by the prices.  There were cheap $100-$200 systems, made out of junk, and then there was the other stuff - from about $1,000 to $10,000.  But even for a grand, it looked like people were being led by the nose.  They weren't buying "junk" per se, but the mark-up between the quality of the products and the price was so wide, I just knew I could do better on my own.  Last year, I set out to build my own system.  I bought an off-the-shelf Yamaha receiver for $200.  The Yamaha got me 550 watts of power and 5.1 channels (2 up front, 2 surrounds and a center channel, along with the expandability of a subwoofer jack).  For the price of the Yamaha, I bought $20 worth of 16-gauge wire (from Home Depot), a pair of modestly-priced titanium tweeters, a pair of midrange domes, a pair of 15-inch woofers (with 90-ounce magnets) and a pair of off-the-shelf crossover circuits.  After buying enough 3/4-inch MDF plywood to turn my wife's entertainment center into a pair of towers, I went to work.  For less than $500, I had the best stereo I've ever had.

Did I reinvent sound as we know it.  No, but the results were still spectacular.  The titanium domes were nice, the midrange domes added a lot of detail and the woofers brought in some very nice bass.  Best of all, by building my own system, I was now in the position to tweak it periodically with "manageable" upgrades.  I wouldn't need a credit card or a finance agreement.  I wouldn't have to worry about APR.  I could just add upgrades as my circumstances might allow.  It was in this frame of reference that I first got interested in the G2Si.

Tweeters come in different shapes and sizes, using different strategies and with different materials.  A lot of the lowest-priced drivers are paper cones, an old technology still with us because of price.  The next step up is the dome.  Metals are better than paper because they have a lower mass, which means they can produce higher highs - and provide better detail.  The greater the mass, the slower the driver.  That's most important when dealing with tweeters.  The downside of any metal is ringing.  Without dampening, you get ringing that is both distorting and distracting.  For audiophiles, this is a love/hate situation because metals can be "crisp" when they're not being "brash."  Titanium is a popular choice for modestly-priced tweeters, which is what I had, but audio greed pushed me to explore what a few extra dollars could do.

Most of the mid-priced tweeters on the market are textile tweeters, sometimes called silk tweeters.  They have a light, airy, mellow sound and are easy to dampen.  But silk tweeters don't have the edge of metal, which is why, even after upgrading to the famous Morel MDT-33 (Israeli tweeters with legendary style), I kept my eye on the ribbons.  Ribbon tweeters have very little mass, allowing them to provide amazing detail.  The problem, of course, is that ribbon technology isn't cheap.  Ribbon tweeters use a series of smaller magnets to suspend the ribbon.  They're more vulnerable to abuse and they need to be properly protected with a good crossover circuit (so you don't fry them by sending bass through them).  A less-expensive alternative is planar, which is similar to the material in a bag of chips.  Planars aren't metal, but they do make great ribbons.  They don't go as high as the true ribbons but they're a step in the right direction.  I bought a pair of Bohlender & Graebener Neo8-PDRs, which turned out to be heaven-sent (and, being the philistine I am, I mounted them on poles and used them as rear surrounds).

But once you play with planars, you'll quickly find yourself wondering what it would be like to have a true ribbon tweeter at your disposal.

When my moment eventually came, I found the G2Si to be everything I'd hoped.  This is a true ribbon tweeter, using a wave-shaped aluminum ribbon (8.5 mm x 60 mm x 0.01 mm) suspended between magnets.  With a mass of only 12 mg, this tweeter has amazing range: from 1,700 Hz to 40,000 Hz (about twice the top end of typical domes and planars).  I crossed it high (5k) because I wanted to use it mainly as a supertweeter, extending the range of my system beyond what my Morels could do.  I wasn't disappointed.  This tweeter has amazing sparkle.

But part of the DIY experience is being enough of a grown-up to see that there are trade-offs with everything.  Insteading of blindly accepting what is given, as if there were no other choices, those who catch the hi-fi bug will end up having to make judgment calls - and more than once.  The Achilles heel of this tweeter is the power rating (only 30 watts RMS/45 watts max).  Most dome tweeters - including the cheap ones - can take more power.  This is not such a huge drop from planars.  The Neo8-PDR, which costs about a third less than this tweeter, has a power rating of 40 watts RMS - but it can take 120 watts max!  When my opportunity came to snatch a pair of these up, one of my concerns was whether I was buying a tweeter I wouldn't even be able to hear!

As it turned out, my fears were overblown.  I wasn't afraid that my 550 watts would burn these tweeters to a crisp; I knew that such a scenario was unlikely.  In a five-channel system, each speaker gets a maximum of 100 watts.  And while that was still twice the max for these tweeters, that wattage would have to be divided among my other drivers - the Morel MDT-33 (capable of handling 200 watts on its own), the Morel MDM-55 (capable of handling another 200 watts) and my Dayton Series II woofers (300 watts RMS/425 watts max).  Even if everything got the same amount of juice, the G2Si would only get 25 watts of that 100-watt load.

Three features of this driver stand out.  The first is the build quality.  This is an aluminum-body driver (Dimensions: A: 4-5/16", B: 3-1/4" x 2-3/16", C: 3-1/4"), which feels heavy, even though aluminum is a relatively light-weight metal.  There is nothing cheap, soft or plastic about this tweeter.  If you threw it at a late-night intruder, you could do some damage (one feature I always liked about the Morels).  Second, the sound is incredibly clean and crystal clear.  You don't realize what a difference it can make until you hear something that cries out for definition.  With this tweeter, there's a general glow of new presence - what some call "sparkle" - but there are also moments when "great" turns into "awesome."  My system was already wonderful, in terms of signal separation and channel clarity.  I could make out a lot of detail already.  But when I installed this driver, I started having moments of shock and awe, when the plucking of a guitar, or a cymbal crash, or just a little bit of detail on a cello bowing, would blow me away.

I've reached the FrankenFi point now, where I can bring dead people back to life.

This is not a driver I would try to pair up in a two-way, but then again, I'm not a big fan of two-way systems.  To me, two-ways are too demanding on the drivers, asking woofers to pretend they're tweeters and tweeters to pretend they're woofers.  I don't want to hear my tweeters below 1k, nor do I care much for my woofer pushing 1k.  My system is really a five-way system (subwoofer, woofer, midrange, tweeter, supertweeter).  Technically speaking, this driver is rated to cross as low as 1,700 Hz (if you have a high-enough-order crossover) but the recommended crossover frequency is no lower than 2,500 Hz.  I prefer a simple first-order crossover (I like the greater sensitivity and more gentle slope) so I cross high at 5k (As I mentioned before, I'm not interested in hearing how low a true ribbon tweeter can go).  If you use it as a supertweeter, to provide an extra layer of presence to your high-end, you can't go wrong.  Not only does 30 watts RMS/45 watts max work out fine - when you're blending this speaker with the rest of your mid/tweet drivers - the higher frequency material is simply less demanding (in terms of wattage) than the lower-frequency stuff.  So, if you cross it high, you'll get more value out of it.

As it is now, I've got five of these (though I didn't pay full price for any of them).  I've got two in each of my front speakers and one I'm using as a center channel (with a 6.6 mF capacitor, to cross it at 3k, since my center channel is all about reinforcing dialogue).  The clarity is to die for - so much so that if my home burned down tomorrow, I'd rebuild and rebuild with these.  Until you put them to work, you don't really know what you're missing.

Note: For those people who are buying components for a dedicated home theater, you might want to consider buying five of these as satellites and using a decent active subwoofer to fill your room with bass.  I don't recommend cutting out other drivers - like woofers, midrange domes and tweeters - because the current practice of buying satellite tweeters and a subwoofer leaves huge holes in the sound spectrum.  But as many people are doing just that, and with garbage, you might as well consider doing it with drivers that aren't.  Roughly the size of an average premium tweeter, these aren't golfball-sized tweeters, but they're still plenty small compared to traditional speakers.  They won't be "invisible" but, depending on their placement, they could certainly be overlooked.  Because of the incredibly-wide off-axis response, their sweet spot is fairly wide (and a lot wider than anything you'll get from a planar).

By the way, if you're afraid of blowing this driver (which could happen if you crank up your 1000-watt system or run it without a crossover), you may be interesed in knowing that the ribbon, itself, costs just under $5.  That may be incentive to look for used models, maybe even blown models, if you want to grab a real steal.

Rated impedance: 6Ω Rated Power: 30W Sensitivity: 96dB/W/M Frequency range: 1700Hz-40kHz Dimension of aluminum ribbon(WLT)F8.5mm×60mm×0.01mm Shape of aluminum ribbon: wave Mass of aluminum ribbon: 12mg Moving area of aluminum ribbon: 510mm2 Gap Flux: 0.58 Tesla Frequency cut recommended: over 2500Hz Material of mounting faceplate: aluminum, CNC processing, surface with anodizing electroplating finish. Dimension of mounting faceplate: φ110mm×T4mm Outside dimension: φ110×D84 Weight: 1.05kg/pc