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About Auracle

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  1. External cross overs

    Hi Guys, Around 10 years ago, I attended a speaker manufacturer presentation. The crossover was external for demonstration purposes. I was left flummoxed as to why anyone would pay so much money (5 digits) for speakers that have a crossover built using 3" nails as soldering posts on MDF. The components weren't even tied down. A plumbing iron or flame was used to bond the molten metal fluid on the nail-heads which had the component leads granny-knotted. He justified this by saying that it gives superior sonic performance. I was dubious so I went home and designed this... I called it the "Versi-tile". Basically a high-current veroboard where you put in your own holes. Manufacturers or DIYers could have some design flexiblilty that looks a little more professional, without designing a dedicated PCB. Well, surprise! How wrong I was.. Looks like nailed MDF won the day then (I only sold about 10), and looks like it still reigns supreme today. PS. I still have a few if anyone is interested.
  2. .....or you could use the bass cannons with infra sonic sound, or substitute cannon balls + black powder.
  3. Hobart GTG late september EOI

    Thanks Linc and Helen. Great food, drink, and hospitality made for another top GTG. Whilst the the clouds looked threatening, only a little precipitation occured during the afternoon. Coupled with double digit temperature, made for a rather balmy environment, -ripe for some healthy discussions! I was privileged to be invited to sit in "the chair" and select some tunes. For a setup that was put together just in the nick of time, I must say, it sounded very nice indeed. Well done Linc. Got to meet some new faces from SNA, and some familiar ones. There was a mainlander here also. Would like to see a few more, -don't be strangers! All-in-all, a fantastic day. I would love to have stayed longer.
  4. Paper machè horns.

    I have 4 of these (still in original packaging). If I remember correctly (since the pic is lousy): 3", (2" cone radiating area), 94dB, 700 - 20kHz. The rear chamber is treated because it was only plastic. Cone is paper with cloth surrounds. I just need a week to find them in my store room.
  5. Thanks for the fantastic offer Matt. Greatly appreciate you thinking of me. At this stage I will respectfully decline as I don't have a home for it. It's bad enough with the rest of my gear still boxed up, I would not feel too good if a high quality bit of kit like that could not be used and enjoyed.
  6. Hi Guys, Sorry for coming in so late. Don't get to spend a lot of time online these days. I've only just noticed this thread/topic and thought I'd put in my 5cents worth. Bass cannons are an interesting concept. I played around with them in my previous life. Briefly, my conclusions came to: 1. Place drivers with the magnet/basket on the outside. *If placed on the inside, the air movement finds an obstacle to it's flow, compressing the back wave and not allowing full velocity. This sets up another mechanical resonance. 2. Do not place drivers in enclosures with any hint of one straight side let alone many. Parallel sides are the worst. * Cylinders have parallel sides and set up harmonic resonances (your "ringing"), that I call the "didgeridoo" effect. It shows up as peaks in the impedance curve, as you have seen. *The only way I have found to mildly subdue this effect without damping the bejesus out of it, is to put ""rifling vanes" in the cylinder. *To (almost) eliminate it altogether, the cylinder needs to taper or curve, -a la transmissionline theory. Have fun!
  7. Hobart GTG late september EOI

    Hey Linc, Just a thought bubble here.... This is a fair crowd already and that's fantastic, but you may want to consider converting that pool into sound lounge to accomodate everyone comfortably. I'm guessing that it will be converted into a large ice bucket instead. Either way it will be impressive.
  8. Maybe I should start another thread on "how to make alcohol whilst listening to background music class". -this is Brian's thread afterall, and we really should get back on topic.
  9. Hobart GTG late september EOI

    Sorry guys for being a bit slow on the uptake. I no longer seem to get email notifications. Haven't performed any setting changes either. Pencil me in! @djb Looking at recent photos elsewhere on SNA, are you sure you're not a local? Shall we warm up the seat for you?
  10. Looks like I've made a rod for my own back. Running an educational GTG as compared to a show-and-tell (and drink) format. Does anyone in SNA land know if a gtg has been run along similar lines, or will this be the first? If anyone has a suggestion for formats, let us know. Does SNA also get a portion of my apples?
  11. Thanx Linc. I'm OK to take up your kind offer. An idea:- If anyone else wishes to attend this class, let us know so we can accomodate numbers. (aka GTG) -please bring an apple for the teacher though.
  12. No tin hat necessary, -you have proven your mettle (no pun intended). I remember somewhere that your driving situation is somewhat curtailed? If so, we just need to arrange a convenient time. I'm actually "working" up north of the state until next week. I'm also dropping in and annoying poor Matt.( Dunno why he hasn't told me to P!$$ off yet.) Cheers
  13. It definitely does seem like it's time to make a live appearance. I do need to find my whiteboard however. I still haven't unpacked my gear due to red-tape. And, since you asked nicely, I will give a primer on attenuation. Definition: "the reduction of the amplitude of a signal, electric current, or other oscillation". =>The DC resistance component of an inductor is but a small but inclusive part of what makes up attenuation when placed in an AC circuit. The coil "resists" the directional changes of Alternating Current as a function of frequency. It's value is calculated using complex number mathematics, and contains an angular component. It's name changes to "impedance" and notation is usually "Z". A "T" filter is "TT" is..... and so on... I also like your parting comment. I should listen to more music before that nutter reduces this world to a smouldering radioactive wasteland. Hope to see you soon.
  14. I've been agonising on how to give you an informative response, since I'm not sure on your depth of knowledge pertaing to filter network theorems and associated mathematics. I will start with a few basic facts hopefully without getting too heavy. Filter networks usually come in the form of T or TT (pi). The quasi parallel sections will tend to want to "resonate" and form peaks (Q) and troughs (nulls) before the attenuation commences, -IF, of course, that is what the application requires, otherwise, the incorrect component values have been chosen. If the application is audio, then that peak/trough should not be a desired outcome. It is actually distortion, and it is audible. Some manufacturers use this trick on cheap subwoofers (they have a wild and woolly sound when played on their own). Consider this; if you are attenuating, how can you have more out that what you are putting in? These types of issues forced me to formulate calculators that allow me to instantly see the changes in curves for each component swap. This has made my crossover design process so much easier and quicker with not many corrections. I can also tailor-make stepped slopes if required. The other bits of info I can offer are:- * With large amplitude signals, metalically cored inductors will saturate and cause audible distortion. Try large air-cored units instead (place them outside and make them a feature). * Ruler flat frequency responses will never be achieved with passive crossovers. Only digital manipulation can achieve this. * If someone thinks they can hear variations less than 2dB, they are deluding themselves. Yes, it's a harsh reality, and it gets worse with age. Consider that the tolerances of the components will give you that alone. --------------------------------- Some of this information you may like, and some you will not. But they are the results of my experiments and experiences, and will stick by them. These days I realise that the time I have left is precious and prefer to enjoy listening to the music ( yes, yet another cliche') on a nice system rather than the system. Also, having just returned from a developing country, one sees things that put our first-world lives into perspective. I think most readers will understand what I mean. So yes, spend on what makes you happy, but always know your limitations. Cheers
  15. Never a truer statement been uttered. 4th order passive crossovers will always severely dampen driver output. Bass drivers require current to "breath" the music into life. Each reactive component added will suck out its' share of power, so the driver will end up with what's left over. This is why with multi-driver speakers, the active miniDSP/DEQX/multiamp setups have it all over the passives in regards to ease of construction, electrical and acoustic parameter corrections. This also explains why creatures like this can slap something together in no time and make it sound decent, whilst purists like us will curse endlessly. Disclaimer: Any references to persons passed or living that feel that they resemble any of these remarks should look in the mirror less often. Should offence be taken by any remarks held within, was sheer fluke on my behalf, and bad luck on yours... Honey! Have I taken my medication tonight?