Infinite Baffle - Tempest-X

The arrival of the Exodus Audio Tempest-X driver promises to break the IB drought in Australia

This page builds on the IB designs done for the now-obsolete Jaycar drivers. For an overview of IB, see the original writeup
With an Xmax of 27mm and a Qts of 0.5, these drivers will allow Aussie IB builders to follow their passion once more.


Audiomarketplace is the sole distributor of Exodus Audio products throughout Australia and New Zealand
These drivers use Adire audio's XBL^2 technology

This writeup is for the Tempest-X driver, which is now superceded by the Tempest-X2. See the drivers page for more info.

One of the designers discusses a few aspects of these future drivers in this thread at HTGuide
With the 15 inch Tempest-X being only a bit dearer than the 12 inch Shiva-X, but with higher sensitivity, it becomes the best current choice for IB designs.
A Product Sheet and Application notes for the Tempest-X can be downloaded from DIYCable


Here are some designs for 2, 4 or 6 driver systems using the 15inch Tempest-X driver

The driver has a dual 6.8ohm voice coils, giving the following possibilities for extracting the most from the Behringer EP1500 or EP2500 amps (only one channel shown)

Single driver with coils in parallel giving 3.4ohms.....extracting around 500w / channel from an EP1500

Two drivers in series, each having their coils in parallel giving 6.8ohms.....extracting around 600w / channel from an EP2500

Three drivers in parallel, each having their coils in series giving 2.3ohms.....extracting around 1100w / channel from an EP2500

WinISD predictions


SPL graph

The available power is estimated using the coil and amplifier arrangements shown above

The blue line is for 6 drivers / 2200w
The green line is for 4 drivers / 1200w
The red line is for 2 drivers / 1000w


Excursion graph

Some high pass filtering is needed to keep excursion to Xmax+10% for the lower frequencies. A 6dB / octave rolloff is sufficient, and is what is modelled here. A DIY high pass filter will run you around $100.

The blue line is for 6 drivers / 12hz hipass
The green line is for 4 drivers / 10hz hipass
The red line is for 2 drivers / 16hz hipass

WinISD files

To save you some work, here are the driver and project files for WinISD ver 0.50a7
Tempest-X driver file
Two driver Project file
Four driver Project file
Six driver Project file

Approximate system costs (April 2009)

There will be a freight calculator up on the Audiomarketplace website soon, meanwhile the following info from the sales team should give you a rough idea on the cost per driver:
Melbourne $22.65
Sydney: $26.43
Brisbane: $28.60
Perth: $41.51
Sending two drivers does not double the price, for example 2 x Tempest-Xs to Sydney will be $30.64 and 8 will be $83.65

Two driver system - 8.5 litres displacement

Drivers $679 + Postage (to Sydney) $30 + EP1500 $470 + DIY hipass $100 = Total $1279

Four driver system - 17 litres displacement

Drivers $1316 + Postage (to Sydney) $45 + EP2500 $620 + DIY hipass $100 = Total $2081

Six driver system - 25.5 litres displacement

Drivers $1995 + Postage (to Sydney) $60 + EP2500 $620 + DIY hipass $100 = Total $2775

You may wish to include a BFD, as most IB builders use one to sweeten the room and dial in a house curve. If you can still find a DSP1124P it will set you back around $200, otherwise you'll need the FBQ2496 for around $300

Whilst the systems outlined here are approximately 50% dearer than the equivalent designs using Jaycar drivers, it is possible that there may be discounts for bulk purchases and / or group buys on the drivers


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Page modified: Sunday, 21-Oct-2018 02:16:09 EDT