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FS: NVA Cubix isobaric loudspeakers

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Item: NVA Cubix isobaric loudspeakers
Location: Melbourne
Price: $1200
Item Condition: Excellent, All original and functioning perfectly
Reason for selling: Surplus to requirements
Payment Method: Pickup - Cash, Paypal, COD Only
Extra Info: These speakers are superb, quirky and very rare in Australia.  If you go to the hifi subjectivist forum in the UK you can read hundreds of posts about how amazing they are and all the nitty gritty on how they are made and such.



They are one of those amazing quirky English brands that has quite a cult following; and for good reason.  The gear sounds wonderful.  The Cubix speakers i have have a massive sound from a  comparatively compact box.  The bass goes down to the 20's thanks to two upward firing isobaric loaded 8 inch bass drivers per cabinet and wall loading.  Each cabinet also has a forward firing tweeter and a side firing tweeter.  So its four drivers per enclosure.  They are designed to be placed near a rear wall for best sound and with the wall loading and dual 8 inch drivers and super dead enclosures (knuckle test will produce sore knuckles due to very thick cabinets and steel lining) they sound effortless, direct and vivid.  Like a lot of great British gear they have superb PRAT (pace, rhythm and timing) and with all the drivers they sound very low distortion.  With the upward firing main drivers and front and side firing tweeters they have a very large enveloping soundstage.  If you check out the forums the people who own these seem to be pretty fanatical about them and some very expensive speakers have been sold with people using these.


The new version of these speakers is 3500 British pounds (not including the steel stands).


Ive included the super heavy steel (sand fillable) stands they were originally purchased with).  They are bi-wirable and bi-ampable.  They use a minimal crossover.


These speakers though modest in size are very heavy.  Local pickup is preferred.


From Richard Dunn of NVA on the Cubix speaker (were the top of the range model with the two tweeters for even power response and dispersion): "

So now we come to the other trick up the sleeve of the Cubes - directionality. Differing frequencies have differing dispersion patterns. The lower the frequency the more omni directional is the polar response, and the higher the frequency the more directional. So our trick is to mount the driver upward firing as the higher it gets in frequency the less it is heard from the listening position and the more its output just contributes to the acoustic ambience of the music (which is peaky anyway due to room nodes). We then use a relatively wide band tweeter which is front firing and directional to provide the frequency range beyond the point the bass / mid driver is naturally (due to doping) and acoustically (due to directionality) rolling off. This makes the only crossover components in the whole speaker necessary as a series protection capacitor to gently roll off the tweeter down to low mid and LF frequencies which would overload and distort (and potentially damage) the small driver, and a padding resistor as the upward driver loses some of the efficiency of output at MF and LF, so if left that way the tweeter would dominate, so it needs taming a little.


The other advantage of the upward firing driver is that it means it is mechanically in phase with its coupling to the listening room, the speaker stand. This stops any rocking motion which induces mf and hf phase problems and a large (90degree) LF phase change as with normal front firing speakers in very low frequency notes. The other bonus of the LF driver position means you get an extra LF natural mechanical extension of the bass frequency so no extra LF driver or extra bass boom box  is required.


The other problem / consideration is what is this all enclosed in and how that enclosure functions. In this situation in reality you are looking at a small box (speaker) creating sound within a much larger box (the room). Now this is a whole new subject in terms of materials, shape and size, better left to another post."

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