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Old 2nd September 2013, 04:11 PM   #1
Gwho is offline Gwho  United States
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Default Vintage NEAR Boom-4 Subwoofer

Any help would be appreciated. I recently picked up a subwoofer from the 1990s that I would like to restore and improve if possible. I cannot seem to find any information on the subwoofer. The subwoofer was built by NEAR (New England Audio Resource). It is a passive subwoofer requiring amplification. It is a ported design that has 4 8" woofers. It appears that each side (2 8") are independent from each other as they are side firing with each side having a separate port. Does anybody know anything about this device (frequency response, efficiency, power requirements etc.). Is it only good for HT or could it be used for a two channel system?

Thanks for any input you may have.

Best Regards,
gwho
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Old 2nd September 2013, 06:57 PM   #2
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If there's two sets of inputs, that suggests to me it was intended to be run in parallel with main speakers, in a 2-ch set-up.

An impedance sweep would be rather useful:
the dip between two impedance peaks is the port tuning. Above and at port tuning, power handling is very large. I'd expect 4x8"s to go rather loud, so long as you don't go below port tuning.

Photos would help, too

Chris
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Old 2nd September 2013, 08:15 PM   #3
Gwho is offline Gwho  United States
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I will try to get some pictures up if I can figure it out.. The speaker measures 3' x 2' and is about 20" high. I do not know much about speaker building (I'm better at electronics). Is an impedance sweep a measurement of the speaker output over frequency?

Thanks
Gary
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Old 2nd September 2013, 08:25 PM   #4
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Quote:
Originally Posted by Gwho View Post
Is an impedance sweep a measurement of the speaker output over frequency?
Gary,

An impedance sweep is a measurement of the speaker impedance, measured in ohms, over frequency.

Speaker output level is measured in decibels, (dB) dB SPL (Sound Pressure Level) using a dB meter or more advanced RTA or FFT devices.

You can determine the Fb (tuning frequency of the box) visually using swept sine waves (available for free on the web), the speaker movement (as well as impedance) will be at minimum at Fb.

Below Fb, ported boxes tend to drop in level at around 24 dB per octave.
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Old 3rd September 2013, 03:56 PM   #5
Gwho is offline Gwho  United States
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I got a couple articles on doing an impedance sweep. I will read them and attempt a measurement.

Thanks
Gary
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Old 4th September 2013, 05:53 PM   #6
Gwho is offline Gwho  United States
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Here are some pictures of the subwoofer. It has two drivers on each side.
Attached Images
File Type: jpg IMAG0915.jpg (481.3 KB, 87 views)
File Type: jpg IMAG0916.jpg (563.7 KB, 81 views)
File Type: jpg IMAG0917.jpg (519.2 KB, 74 views)
File Type: jpg IMAG0918.jpg (507.8 KB, 75 views)
File Type: jpg IMAG0919.jpg (523.0 KB, 74 views)
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Old 4th September 2013, 05:55 PM   #7
Gwho is offline Gwho  United States
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I was told that the woofer cone is metal.
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Old 5th September 2013, 06:57 PM   #8
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Since you didn't provide the model number, try here.

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Old 6th September 2013, 10:31 AM   #9
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Old 6th September 2013, 01:37 PM   #10
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