It was all supposed to be so easy. I needed a new pair of loudspeakers. Instead of multi-channel sound, it was just going to be stereo. To keep things simple, it was also supposed to be a wide-range speaker, since I had had good experiences with those years ago. I found my gateway drug pretty quickly too: the Gradient Axis series, more specifically the AX-6 HR. However, as my wife pointed out, “You can’t do it. In a couple of months, we’ll be back to having five boxes in the living room.”
As so often, she was right in the end. Even though I was, and am, actually very satisfied with the “Axis of Good.” It’s always amazing, but true, that you don’t need more than a little bit of paper on each side to hear good music. The shortcomings of these wide-range speakers, at least on paper, are balanced out by their reproduction of the stage and voices. The theoretical catastrophe, in my opinion, is fantastic in practice.
But there was something missing when it came to movies, and – since I’m not that old yet – for new-fangled toys like video games. So what can you do when there’s no such thing as an Axis Center? After all, it’s usually pretty awkward balancing a TV on top of a pedestal speaker. Hey, we’re in the business of building our own loudspeakers here!
But a center loudspeaker with wide-range speakers? Wouldn’t that cause a lot of problems? Well, it exists elsewhere, and as Grandma always said, you won’t know until you try.
Still, I didn’t want to approach the project in total ignorance, so I started with one of the Gradient Axis boxes. I needed a little bit of calculation help, which I found in the free program HornResp, since I definitely wanted a horn reflex Center – the whole thing needed to work without subwoofers. It was soon clear that a Center with the AX-5 wouldn’t be much smaller than a Center with the AX-6; an AX-8, on the other hand, needs a lot more air behind it. Oh well, that was nothing new. People had already written about that on loudsspeakerbuilding.com.
Still, the shape of the baffle board does influence the sound to a certain extent. Since I wanted to deviate from the traditional form more than a little, I used another small freeware tool called Edge, which can calculate how the baffle board affects the sound. That particular influence wasn’t too large. I talked to Udo, who thought the room itself would screw up a lot more of the sound balance. Okay, maybe that’s not exactly how he put it, but it’s completely true.
Still, I did want them to be a little bit smaller, so I reduced the volume to 31 liters. That makes the horn channel longer, though, which isn’t very practical. So we’ll just make the horn channel a little smaller – it fits, great, let’s build it.
One last assembly plan, then I bought the wood and… just let it sit there, because all summer long I either didn’t have enough free time or the right weather. But at some point it’s just time, because you finally want it to be finished. So I dug out the wood pieces, realized that the man at the saw must have had trouble understanding measurements because none of the boards were exactly the right size, had the pieces re-cut, and finally started building.
The assembly itself is really simple. There is only one reinforcement on the back wall, the reflex boards and the front have a 10° angle, and that’s it.
Because that was much too easy for me, I had to go ahead and veneer the horn channels to match my two big speakers. If you like things simple, you should avoid this step!!! Adding veneers to the horn channels post-assembly is damn hard, and it only works with contact pressure or maybe contact glue. I discovered that because I had forgotten to take those details into account with the normal AX-6 HR before I put it together. So definitely add the veneer before you assemble it. The insides of the side walls and the outsides of the reflex boards are no big deal. The little strips for the top and bottom sides, on the other hand, require precision down to a tenth of a millimeter. To make sure everything else fits, they need to be cut very precisely.
By comparison, the rest of the assembly was fairly uncomplicated. Even the angles aren’t necessarily hard – in an emergency, you can use a rasp or some guide rails with your hand saw. The rest of the veneer work was no problem either, using the iron-on method. Still, I recommend waiting a little while after you iron, and then ironing out any air bubbles that come up before you start sanding and painting. After sanding it three times and applying two coats of hard oil, the woodworking part was finished.
I ordered the assembly kit and put everything together; I welded the crossover onto a little panel cut out of a cork tile, and it was finished.
Connecting the Axis Center to the AV receiver was much faster than building it. It does take a while to break it in, especially with wide-range speakers. Still, it was soon clear that this would work. Admittedly, “it just works” is a pretty short sound description, but the important thing with center loudspeakers is the difference from the front speakers; in my setup, that difference is relatively small. The Center stands on an open 50-cm-tall TV board prototype (that’s why it still looks so ugly in the pictures) – so it’s slightly lower than the normal ear height. That makes the voices a nuance lower than with the normal AX-6 HR; the bass has a little more kick but a little less depth, and that’s about it. Most of the differences probably have to do with the setup. All in all, though, I’ve never had a center speaker that meshed so smoothly with the front loudspeakers. Most of them actually do much worse than the reformatted Axis, and that’s without any initial measurements or EQ, in other words for older AV receivers or newer ones in Pure Direct mode.
There’s plenty of volume even without subwoofers, at least for a rental apartment. Since the frontal trinity goes up to 40 Hz in my room, I can really do without a separate bass. It’s just too bad that there’s no room to use the AX-6 for the rear speakers too – then the overall sound would be perfect.
But wasn’t there something else? A wide-range speaker as a center? The evil clustering in the high range? Not a problem in a normal living room. When you have two or three people sitting on the couch, it’s really no problem at all. For the typical wide-range drop-off in the high notes to be noticeable, you have to be sitting pretty far outside the axis. Plenty of horizontal D’Appolito centers make more of a mess with the sound. Another solution might be better for a full-sized home theater, but you would need a subwoofer in any case. I definitely don’t need one of those right now. Although… with a Gradient AXT-10, I could be swayed.
Short note from the editors: The crossovers for the Center and the AX 6-HR are identical. The assembly kits are only distinguished by the cabinets, and you do not need to buy an item called the AX 6-Center separately.