Tempest specs (1 Viewer)

[Jeremy Illingworth]

I have tried to download the white paper for this but my Adobe Acrobat won't open anything off the net and I've tried several times to download the new one from Adobe but my computer won't allow it.
What is the cone excursion of the Tempest? I've got a big spike up to about fifty mm at 12Hz dropping to eight at 14Hz. After that it builds up to thirty five mm at 30Hz.
And what is the volume of the driver in cubic inches?
On my Free Air SPL at 1 Meter chart I've got a small spike around 12Hz which drops a bit and then climbs gradually. I can reduce this by making the vent smaller which brings airspeed up too high. Do I just live with this?
Right now it's 300L with a 15x75 cm (six by 30 inches) port. The resonance frequency is 13.8. Is that okay?
jeremy

 

[Jeff Rosz]

hello,
right off the whitepaper..tempest xmax is 16.4mm. its volume is 305 cu in. as far as spikes in your FR and cone excursion, there is little information that will be sent to the woofer in that bandwidth with a few exceptions. movies like ronin, blade, and lost in space (you could search this very board about lost in space) have some subsonic info. do you listen to pipe organ music? if you are worried about it, get a subsonic filter. i would be more worried about 35mm @ 30hz. are you using lspcad? i think it graphs excursion in peak-peak (anyone?) where 35mm would exceed xmax but not xmech (anyone?). dont make your vent smaller, try experimenting by making the box a little smaller to load the driver a bit.

 

[Jeremy Illingworth]

So is Xmax (one way) times two maximum cone excusion? If so I'm 2mm over. Do I reduce box volume to lower this? What else would do it?
jeremy

 

[Dustin B]

You could just leave it too. 2mm over Xmax is nothing to worry about. Unless you really really start pushing the sub you won't ever get near that, and even if you do, it just means distortion will come into play a little bit, you won't be bottoming the driver. Xmech (the mechanical limit of the drivers travel, where bottoming will occur) is a lot more than 2mm higher than Xmax.
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Dustin
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My Adire Tempest Sonosub