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π Speakers 12π [message #28304 is a reply to message #28299] Sun, 21 October 2007 13:56 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)
http://prosoundshootout.com/Photos/2007/12Pi.jpg
12π basshorn sub

First, we measured impedance and found Zmin to be 2.8Ω. So 16.7v is required for 100 watts, 23.7v for 200 watts, 33.5v for 400 watts, 47.3v for 800 watts and 66.9v for 1600 watts.

http://prosoundshootout.com/Measurements/2007/12Pi_Impedance.jpg
12π impedance

Next, we measured output at 28.3v. Since we measured 10 meters away, the values correspond to 2.83v/1M.

The blue line is SPL, and the violet line shows distortion. Since measurement was taken at 10 meters, add 20dB to find SPL at 1 meter. With 100 watts input, the 10 meter measurement works out the same as 1 watt input measured at a distance of 1 meter.

http://prosoundshootout.com/Measurements/2007/12Pi28v.jpg
12π response at 10 meters with 28.3v input (2.83v/1M)

From this, we perform an inverse FFT to obtain impulse and step response:

http://prosoundshootout.com/Measurements/2007/12Pi_Impulse.jpg
12π Impulse Response

http://prosoundshootout.com/Measurements/2007/12Pi_Step.jpg
12π Step Response[/img]

Measurement at 100 watts:
http://prosoundshootout.com/Measurements/2007/12Pi100w.jpg
12π response at 10 meters with 16.7v (100w) input (1W/1M)

Measurement at 200 watts:
http://prosoundshootout.com/Measurements/2007/12Pi200w.jpg
12π response at 10 meters with 23.7v (200w) input

Measurement at 400 watts:
http://prosoundshootout.com/Measurements/2007/12Pi400w.jpg
12π response at 10 meters with 33.5v (400w) input

Measurement at 800 watts:
http://prosoundshootout.com/Measurements/2007/12Pi800w.jpg
12π response at 10 meters with 47.3v (800w) input

Measurement at 1600 watts:
http://prosoundshootout.com/Measurements/2007/12Pi1600w.jpg
12π response at 10 meters with 66.9v (1600w) input
Comparison of systems [message #28305 is a reply to message #28299] Sun, 21 October 2007 14:26 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)
The charts below overlay response curves of each subwoofer tested at 100w, 200w, 400w and 800w. Only the BassMaxx Deuce and the 12π hornsubs were tested at 1600w. The BassMaxx response curve is orange, Titan is green, Growler is brown and π is blue.

Measurement at 100 watts:
http://prosoundshootout.com/Measurements/2007/100w.jpg
Response curves at 100 watts

Measurement at 200 watts:
http://prosoundshootout.com/Measurements/2007/200w.jpg
Response curves at 200 watts

Measurement at 400 watts:
http://prosoundshootout.com/Measurements/2007/400w.jpg
Response curves at 400 watts

Measurement at 800 watts:
http://prosoundshootout.com/Measurements/2007/800w.jpg
Response curves at 800 watts

Measurement at 1600 watts:
http://prosoundshootout.com/Measurements/2007/1600w.jpg
Response curves at 1600 watts
12π - differences between versions [message #28306 is a reply to message #28304] Tue, 23 October 2007 08:23 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)

The 12π basshorn subwoofer measured in 2005 was a prototype, the one brought this year was a first production model v1 and we've just finished with a second production version v2 that performs even better. The differences are described here:
Re: Fitzmaurice Titan 48 [message #28307 is a reply to message #28302] Wed, 24 October 2007 09:31 Go to previous message
lelandcrooks is currently offline  lelandcrooks
Messages: 12
Registered: May 2009
Chancellor
Thought I might add a version definition also. The t48 can be configured with two chamber sizes. The model tested is the large chamber version, which improves response below 40hz. The smaller chamber improves response above 40 hz., up to a couple of db across the board, at the expense of response below 40hz.

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