Build a hi-fidelity Pro Audio Cabinet that sets the standard!

Tired of crappie sounding PA cabinets?  
(You DO realize that in a world of mass produced PA cabinets - it's mostly the cabinets themselves that are to blame!)

This Decware original Ultra-flex design represents the most efficient cabinet you can build for a single 12 inch woofer.  In fact most drivers see better power handling and improved linearity in this box. We love it because of it's low distortion, good tone, and incredible speed. They deliver a chest hit that you are sure to remember.


These can be used as mains for a PA, or flipped on their side and used as stage monitors. Use your favorite 12 inch pro audio driver and a 4 1/2 x 12 inch compression horn with a decent crossover network.


The ultra-flex design is optimized to get the back wave of the woofer out of the cabinet with great efficiency while offering excellent reflex loading to preserve power handling and ensure smooth response.  The 4 inch PVC pipe at the rear acts as a wave guide transferring energy from the woofer to the ducts.




All of the angles in this box are 45 degrees making it a very simple enclosure to construct.



Although you're welcome to set this up with your own favorite combination of drivers, we've designed a kit that configures these cabinets as monitor speakers or stage monitors using the following high quality components.


Parts costs for a pair of speakers are just under $500.00



These GOLDWOOD deluxe pro audio series drivers are designed for high-power, high SPL pro audio systems. The large edge-wound voice coils on aluminum formers are designed to handle extreme amounts of power with ease. Massive cast aluminum frames support the large motor structure to provide years of service in the field.

*Power handling: 600 watts RMS/1200 watts max *VCdia: 4" *Le: 2.01 mH *Impedance: 8 ohms *Re: 7.16 ohms *Frequency range: 75-3,000 Hz *Fs: 68 Hz *SPL: 94.1 dB 2.83V/1m *Vas: .91 cu. ft. *Xmax: 5.4mm* Qms: 12.31 *Qes: .56 *Qts: .53 *Dimensions: Overall Diameter: 12-1/4", Cutout Diameter: 11-1/4", Mounting Depth: 4-1/2".


These molded horn lenses are constructed of high-impact ABS and feature the standard 1-3/8"-18 TPI screw-on driver mounting threads. Some models feature a metal thread insert for added durability.

Cutout: 10-3/4" W x 3-1/4" H


Using Butterworth alignments, with 12 dB slope on the low pass and 18 dB slope on the high pass. For added flexibility, a 100 watt L-pad is included to allow adjustment of the tweeters output level. The high pass protection circuit contains tungsten filament lamps that safely absorb input overloads to help prevent tweeter burnout.. 600 watt RMS power handling. Crossover frequency: 3,500 Hz. . Enclosure hole cut out: 6" W x 4" H.


The D210Ti is the driver of choice for high performance, high value professional systems. It is recommended for use in monitor speakers, stage monitors and surround speakers in movie theaters. The titanium diaphragm assures high sensitivity, low distortion and smooth, extended frequency response. Compatible with 1-3/8"-18 TPI mount horns.

Specifications: • Power handling: 80 watts RMS/160 watts program (with recommended 2,000 Hz, 12 dB/octave crossover) • Minimum recommended crossover: 2,000 Hz (12 dB/octave) • Voice coil diameter: 1.7" • Throat diameter: 1" • Impedance: 8 ohms • Frequency response: 800-20,000 Hz (no crossover) • SPL: 107 dB 1W/1m • Magnet weight: 23.5 oz. • Dimensions: Diameter: 4.53", Depth: 2.83".

 These components are available from Parts Express

 Using a 107dB tweeter in combination with the L-Pad, 18dB crossover slope and tungsten filaments ensure this setup will handle the full 600 watts it was designed for.

Ideal for it's application, here is the low frequency response of this driver compliment at 1 watt/1 meter:

Notice that the peak at 80 Hz is 6dB giving the speaker warmth and great low end punch. The 60Hz figure is -4dB which will actually be referenced against the peak. This gives a total reduction of apparent 60 cycle hum from amplifiers of 10dB or half as much hum as most other speakers.  A neat trick resulting from this woofer and cabinet combination. (Other woofers WILL vary).


To use this cabinet design in applications that demand more bass extension, we have another neat feature... called the tuning board.  

Calculate your model based on 1.33 cubic feet for the woofer of your choice and create a tuning board for it!

With the removable tuning board(s) you are able to cut a minimum 18 square inch slot of different widths to accommodate different tuning frequencies.



By cutting a slot in the bottom panel, the tuning board can be slid into the cabinet as shown.  Each tuning board can have a slot cut down the center of it with the specific area required to hit the f3 for the woofer you select.

This makes it possible to fine tune your cabinet to a variety of woofers and or applications.  

The modeled response based on 1.33 cubic feet will vary in real life because the "port" will be firing into a secondary chamber.  This will add significant gain to the porting frequency (and length to your calculated port) and alter the response enough that getting an accurate computer model is not likely to happen.  

That's okay, because published Thiel & Small parameters are never accurate. Unless you have a way to hand tune a cabinet to a specific woofer, your idea of a perfectly tuned computer modeled cabinet becomes a simple fantasy.

The correct area to remove from the tuning board can be determined by ear by first sliding the solid board (as shown) down into the cabinet until it reaches a distance off the bottom where the cabinet becomes tuned. (Simply listen for the most bass). Note the position off the bottom and calculate the square inches of the opening.  Now apply the area of that opening to a slot cut in the center of the tuning board and push it all the way into the cabinet.




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