CUBE 1

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Dr Bunsen Honeydew
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CUBE 1

Unread post by Dr Bunsen Honeydew »

I am building a pair of Cube 1 for Zebbo at the moment so I thought I would do some pics of the process and progress.

1st pic - crossovers - or more to the point, lack of them.

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Dr Bunsen Honeydew
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Re: CUBE 1

Unread post by Dr Bunsen Honeydew »

Drive units

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Other side and part of my foot :roll:

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selby
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Re: CUBE 1

Unread post by selby »

I'm sure you've explained before but as this is on a specific thread could you tell us why the Cube is designed how it is?

Really interested to get a better understanding of how and why it gives better sound, positioning tips, if there are any negatives what they might be etc?

I've seen the case in the flesh and they look really nice, heavy, solid and well finished.
My Kit – I moved to home theatre setup sorry...Denon SR7011, Anthony Gallo A'Diva SE Fronts, SpeakerCraft Profile AIM LCR3 One Rears, BK Electronics XLS200-DF MK2 Sub, Epson Projection.

But I would love a cheeky little AP10, AP20 sort of amp for a bedroom setup...

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Dr Bunsen Honeydew
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Re: CUBE 1

Unread post by Dr Bunsen Honeydew »

I have written about them many times, this with lots of other inf and opinions on a thread at the old forum http://thehifisubjectivist.noadforum.co ... ?f=3&t=214

It is very simple like all things done right in audio work. If a driver has problems or is not quite right for the job then you have two choices - do it electrically or do it mechanically. Electrically is a problem as it changes the phase (timing) relationships of the signal (music) across the band being tailored, this is musically destructive, and the more complex that electrical circuit the more of a problem - or do it mechanically, which means doping and tailoring the driver to make it a mechanically more acceptable compromise. The major purpose of the damping / doping is to control the HF response of what is a relatively large driver for dealing with HF work as the response becomes peaky as resonance points are reached in the shape and materials the driver is made from. Doping puts material of other resonant frequency in to infill the nulls (suck outs) and flatten the nodes (peaks). This is a partial success for solving the problem as the driver will still harden up and distort the HF output.

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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Dr Bunsen Honeydew
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Re: CUBE 1

Unread post by Dr Bunsen Honeydew »

And another thread http://thehifisubjectivist.noadforum.co ... p?f=3&t=94

And more at the old forum about both Cube 2 and Cubix.

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howardc1951
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Re: CUBE 1

Unread post by howardc1951 »

I was just curious to know what cable you use in them.

jammy395
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Re: CUBE 1

Unread post by jammy395 »

And are they stuffed full of wadding or that egg box type foam....etc?

Daniel Quinn
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Re: CUBE 1

Unread post by Daniel Quinn »

Jammy , your being humorous yeah !!!!!

jammy395
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Re: CUBE 1

Unread post by jammy395 »

mmmmh......yeah....kind of. :shifty:

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Re: CUBE 1

Unread post by Daniel Quinn »

No wadding no padding , no nuthin in the cubes . You will find a least 2 dozen comments from the doc bemoaning the destructive properties of speaker damping materials :lol:

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