Help building box for 2" drivers

[CoolbeaN]

Hey, I purchased a pair of 2" Tympany full range drivers.
Tymphany 2" Full-Range Neodymium Driver

I want to build a set of desktop speakers. From some of the reviews folks have had good results using a 2 foot pipe for an enclosure. I would rather build a box than use PVC. Would building a folded horn work well for this? If yes, how do I determine the what dimensions to use for the box?

[CoolbeaN]

Here are the specs for the drivers.
Specifications: *Power handling: 10 watts RMS/20 watts max *VCdia: 13/16" *Le: 0.12 mH *Impedance: 8 ohms *Re: 7.1 ohms *Frequency response: 148-20,000 Hz *Fs: 148 Hz *SPL: 83.7 dB 1W/1m *Vas: 0.008 cu. ft. *Qms: 3.4 *Qes: 0.54 *Qts: 0.46 *Xmax: 1.45 mm *Dimensions: A: 2-5/8", B: 2", C: 1-3/8".

[enigmaticEntity.]

I wouldn't have any idea how to design a folded horn; but you could try putting the T/S into a program like WinISD (the free download one) or UniBox or BassBox Pro. You most probably still won't be getting much output below 140Hz whichever design you go, especially with an X-max of 1.45 mm and a cost of $5 each .

I'd focus more on flattening the frequency response if that is needed, or else just go with a sealed box (too big is better than too small) with stuffing and a capacitor high-pass filter to reduce excursion at bass frequencies you won't hear, eg. 60Hz from a 2'' full-range is very quiet...

When designing boxes, usually we make the dimensions in multiples of 1.6, eg. 0.6, 1.0, 1.6, to reduce standing waves in the bass. One thing I forgot - you should use a Baffle Step Compensation (BSC) network (just a resistor and an inductor), or else the speaker will not sound "warm" and you will probably dislike the sound after a while of listening.

Are you considering building any sort of subwoofer for this project?

[mashaffer]

Even with a line I don't think you will be able to get below 100Hz (I haven't modeled this one but hornresp is probably the easiest program in which to model it) and the driver will be unsupported below the tuning frequency so you will need to high pass filter in order to protect the driver.

That being said a folded line if done right should give you better performance than an actual pipe because the higher resonances will be better controlled.

Without a "subwoofer" I would just use it sealed as that is the safest way for the driver. JMO.

[CoolbeaN]

Any reason this wouldn't work?

Using quarter inch ply. Box is 13 x 3.5 x 4 inches.

[planet10]

Voigts without mass loading tend to have a lot of ripple in the bottom of their passband.

dave

[CoolbeaN]

Mass loading as in stuff the first 2/3 right? I plan on it.

[planet10]

Mass loading as in a resticted terminus.

dave

[borispm]

Coolbean, I guess the "mass loading" Dave mentioned is something like a "reflex port". Adding "mass" i.e. volume of air in the port in this case, to the "exit" of the voigt pipe.
Try to add a small 1" dia port and tune it, I would say.

[CoolbeaN]

So what makes this design a Voigt Pipe instead of a MLTL. If it were a horn the speaker would be right at the end of the pipe as far as I understand it.... but then I don't understand why the Frugal Horn Mk.3 is a horn.
As this box is only 3.5 inches deep on the inside, any guesstimates as to what diameter/length I should be porting it with?