checking calculations

mountainhick · 19th January 2010, 06:04 PM

I plugged some driver parameters into an online enclosure calculator. Just want someone who knows enclosure calcs to double check for me. I am a great woodworker, but I totally suck at math.

Does this work out correctly?

Driver:
Fs: 24.0000 Hz (Free air resonance)
Vas: 2.6486 ft^3 (Compliance volume)
Qts: 0.2190 Total Q
Qms: 1.3000 Mechanical Q
Qes: 0.2640 Electrical Q
Sd: 0.0130 M^2 (Piston area)
Xmax: 3.1800 mm (Cone excursion, linear)
Revc: 6.5000 ohms (DC resistance)
Znom: 8.0000 ohms (Nominal impedance)
Pmax: 35.0000 watts maximum rated power

Closed box results:

Vas = 2.65 ft^3
fs = 24 Hz
Qts = 0.219
Qtc = 0.707

Vb = 0.28 ft^3
f3 = 77.49 Hz
fb = 77.48 Hz

Also, for using a pair in a single enclosure, do I just double the box volume?

Thanks

bjorno · 19th January 2010, 11:22 PM

Quote:

Originally Posted by mountainhick

I plugged some driver parameters into an online enclosure calculator. Just want someone who knows enclosure calcs to double check for me. I am a great woodworker, but I totally suck at math.

Does this work out correctly?

Driver:
Fs: 24.0000 Hz (Free air resonance)
Vas: 2.6486 ft^3 (Compliance volume)
Qts: 0.2190 Total Q
Qms: 1.3000 Mechanical Q
Qes: 0.2640 Electrical Q
Sd: 0.0130 M^2 (Piston area)
Xmax: 3.1800 mm (Cone excursion, linear)
Revc: 6.5000 ohms (DC resistance)
Znom: 8.0000 ohms (Nominal impedance)
Pmax: 35.0000 watts maximum rated power

Closed box results:

Vas = 2.65 ft^3
fs = 24 Hz
Qts = 0.219
Qtc = 0.707

Vb = 0.28 ft^3
f3 = 77.49 Hz
fb = 77.48 Hz

Also, for using a pair in a single enclosure, do I just double the box volume?

Thanks

Hi mountainhick,

You are right, doubling drivers in a closed box, doubles the volume.
Some verifying calculations:

b

PeteMcK · 19th January 2010, 11:22 PM

Unibox gives me a Qtc of .251 for 2.65 cu ft, an f3 of 71 and an fb of 95.5 for .28 cu ft;
yes, you double the box vol for 2 drivers.
are you using these as mids? if so, a sealed box of ~ 9L (.32 cu ft) looks good for 2 drivers for a Qtc of ~ .707

mountainhick · 19th January 2010, 11:27 PM

Cheers. Yes, these will be used with a subwoofer and crossed over around 80hz

19th January 2010, 06:04 PM	#1
mountainhick diyAudio Member Join Date: Jan 2010	checking calculations I plugged some driver parameters into an online enclosure calculator. Just want someone who knows enclosure calcs to double check for me. I am a great woodworker, but I totally suck at math. Does this work out correctly? Driver: Fs: 24.0000 Hz (Free air resonance) Vas: 2.6486 ft^3 (Compliance volume) Qts: 0.2190 Total Q Qms: 1.3000 Mechanical Q Qes: 0.2640 Electrical Q Sd: 0.0130 M^2 (Piston area) Xmax: 3.1800 mm (Cone excursion, linear) Revc: 6.5000 ohms (DC resistance) Znom: 8.0000 ohms (Nominal impedance) Pmax: 35.0000 watts maximum rated power Closed box results: Vas = 2.65 ft^3 fs = 24 Hz Qts = 0.219 Qtc = 0.707 Vb = 0.28 ft^3 f3 = 77.49 Hz fb = 77.48 Hz Also, for using a pair in a single enclosure, do I just double the box volume? Thanks

19th January 2010, 11:22 PM	#3
PeteMcK diyAudio Member Join Date: Feb 2002 Location: Sydney	Unibox gives me a Qtc of .251 for 2.65 cu ft, an f3 of 71 and an fb of 95.5 for .28 cu ft; yes, you double the box vol for 2 drivers. are you using these as mids? if so, a sealed box of ~ 9L (.32 cu ft) looks good for 2 drivers for a Qtc of ~ .707 __________________ ‘today… there lives alongside the twentieth century the tenth or thirteenth. A hundred million people use electricity and still believe in the magic power of signs and exorcisms” Trotsky

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19th January 2010, 11:27 PM	#4
mountainhick diyAudio Member Join Date: Jan 2010	Cheers. Yes, these will be used with a subwoofer and crossed over around 80hz

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