Audio

REVIEW: Krix Helix

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68The Krix Helix speakers are part of its ‘concealed audio’ range. And quite the range that is, including the six driver, three way Epix, down to the entry level Holographix. The Helix speakers are one step up from those, writes Stephen Dawson.

Each Krix Helix unit is a compact, round two way ceiling speaker, with a 20mm dome tweeter mounted in front of a 160mm bass/midrange. The latter features what Krix calls a ‘curvilinear’ polypropylene cone, along with a 38mm voice coil on a Kapton former.

There’s a substantial crossover network attached to the side of the case, with spring clips to secure the speaker cable.

Long time readers will see that we’ve reviewed quite a few installation speakers, and most of them follow a particular pattern for installation. You remove the grille, which normally covers the whole face of the speaker, including the surrounding lip, exposing four or so screw heads. These screws are long and when tightened swing out clamps behind the speaker and drag them down, eventually bringing them down to clamp on ceiling panel. To remove them you just turn the screws the other way. The clamps loosen and eventually swing back behind the body of the speaker, allowing you to pull them straight out.

These speakers are radically different. First, the grilles don’t appear to be removable. At least they defeated my efforts, although of course I didn’t dare push the matter the point of possible damage. So how do you tighten the screws?

Not necessary: it doesn’t have any. Instead, the whole speaker is a giant screw! Hidden behind the front, firmly affixed to the body, are three 9.5cm long spring metal arms, stretching out tangentially from the body, almost parallel to the grille. It’s a bit hard to envisage, but you hold them in so that they’ll fit into the hole you’ve cut – a 164mm diameter cutout is required – and then you push the speaker into the hole. Obviously you’ll have released these arms by then. Krix calls them ‘mounting wings’.

Then you rotate the speaker. The wings form a groove in the edge of the cut out and draw the speaker in tightly.

If you later wish to remove them, you just rotate the other way, and the speaker is screwed out.

I don’t know, perhaps this is a common arrangement, but I’ve never seen it before and Google suggests that the term ‘mounting wings’ usually refers to a flat plate to which a speaker can be secured if the ceiling panel isn’t very strong. Krix also refers to this system as ‘twist and lock’. Some Niles ceiling speakers have a ‘twist and lock’ system, but in that case a mount is installed and the speaker twists into that.

Anyway, this is a rather clever arrangement. As with any installation, you should pause a moment before inserting the speaker and choose an initial orientation to ensure that you’re not going to run afoul a ceiling beam.

Krix calls the body of these speakers ‘semi-sealed’ in order to keep out dust and whatnot. There is a narrow gap between the body and the magnet assembly, which is exposed at the rear, plus some smaller holes near the face. We doubt that anything would get it, but just to be on the safe side, a cover over them in large ceiling cavities might be worthwhile.

So, are there any advantages with this mounting mechanism? The most obvious one is size. I checked out half a dozen ceiling speaker reviews I’ve done in these pages and when you compare nominal speaker cone size to the size of the speaker grille, these are the smallest by quite a margin. The grille is 30mm bigger than the bass driver. The average for the other six was 69mm.

On the subject of size, the mounting depth of these speakers is 86mm. The stainless steel grille is finished in white and can be painted to match décor.

Krix says that they are IP54 dust and splash resistant. That means that “ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment” and “water splashing against the enclosure from any direction shall have no harmful effect”. I take it to mean that they’re talking about the face of the speaker with this rating. That, along with the use of “weather resistant materials and … a rust resistant stainless steel grille”, gives them the confidence to suggest suitability for outdoor mounting.

In use

Before using them properly to, you know, listen, I did a couple of quick trials, and I’ve got to say that the bass was quite unimpressive. So I did a quick measurement and the reason instantly became clear. The response peaked at 950Hz and fell away at 6dB per octave below that point. At 220Hz it was down by 21dB.

But don’t panic! All that was with the speakers ‘naked’, so to speak. Which is to say, not built into anything, nor with any enclosures. I had mistaken what looked like a sealed casing to actually be sealed.

So I installed the speaker in compact boxes and re-ran the measurements. Well, that was different! Now the speakers were essentially covering the range from 70Hz to 20,000Hz! The peak at 950Hz was tamed a little and the treble peaks and troughs were moderated somewhat.

But don’t take those measurements as gospel either. The newly enclosed speakers were in the normal position in which I place my speakers, which is about a metre from the back wall in a place where imaging and midrange and treble performance sounds wonderful in my room. And that, obviously, is not where these speakers will be installed. They are designed to be placed flush with a large flat surface at a room boundary. There the bass is likely to be further extended and enhanced in level, and will certainly not be subject to the suck-out at 50 to 60Hz my measurement showed.

All of which is to show that positioning and installation matters. I do these kinds of tests not to show what results one will get from the speaker in any particular installation, but to give a sense of what the speaker is capable of delivering. Can it deliver respectable bass? Clearly the Krix Helix can do very solid mid-bass and, ceiling installed, might even reach the claimed 45 hertz.

Will the Krix Helix actually deliver deep bass? That depends on how you install it.

And the third question: even if it can, should the Krix Helix deliver deep bass?

I’d vote ‘no’. Let’s say that it can do 50Hz (properly installed) at the same level as the other frequencies. We must remember we are talking about a 150mm driver. To produce deep bass a certain amount of air has to be moved. If the piston is large, it doesn’t need to pump very far to move that air. If it’s small, it has to move in and out a long way. That adds distortion (the longer the throw, the greater the non-linearities). And when the level starts to get high, the limits over which the cone can move are reached.

So, let’s accept that the Krix Helix can deliver 50Hz, we should still set the crossover to 80Hz, or even 120Hz, and let the subwoofer carry those frequencies.

All that was quite the diversion, but it’s worth keeping in mind for all compact installation speakers (or, indeed, smaller standalone speakers).

Listening proved that the speakers delivered fine sound, with extended treble and (when installed in the boxes) decent and well articulated bass. The sensitivity is a little low, so I poured quite a bit of power into these speakers and they happily soaked it up to produce high levels without any sense of distortion, and only the slightest amount of dynamic compression. Drums still rang out above the mix and there was a degree of mellowness in the sound, avoiding a harsh or aggressive result. Treble dispersion seemed reasonable, which is important given that the tweeter can’t be directed or aimed.

I’d be happy using them as standalone under-eave speakers on a patio, and even more so for in-room Dolby Atmos installations.

Conclusion

The Krix Helix speakers have a number of things going for them: robust both physically and electrically, they are wide ranging, able to produce high levels, and very, very compact. And they are quite reasonably price.

About Stephen Dawson

Stephen Dawson

Stephen Dawson is one of Australia's leading freelance writers on home entertainment equipment. Based in Canberra, Stephen has had over 3,000 articles published in both local and national publications, mostly reviewing AV equipment.

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