Film-Tech Forum ARCHIVE: Replacement Boston Acoustic A70 woofer

This is topic Replacement Boston Acoustic A70 woofer in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jeremy Weigel (Member # 4208) on 01-06-2013, 07:42 PM:

Anybody have the specs on the woofer in the Boston Acoustic A70? I have one that is blown and looking for a replacement.

Posted by Louis Bornwasser (Member # 3063) on 01-06-2013, 08:27 PM:

I have used an Eminence 8" round speaker with a large magnet as a direct replacement for years. The one I used in the Entertainment Engineering monitors. (I don't have any more speakers.) Actually any large magnet, robust 8" speaker should be fine. Most thought the sound was a little better. louis

Posted by Jeremy Weigel (Member # 4208) on 01-06-2013, 10:37 PM:

Thanks for the info Louis.

Posted by Jeremy Weigel (Member # 4208) on 01-10-2013, 11:48 AM:

Update:

I pulled another driver to double check ohm rating with a meter since there isn't any info stamped on them. They are a 4ohm driver. I found this unit Simply Speakers. Seems like a fairly robust unit. Thoughts? Anyone used Goldwood brand drivers?

Posted by Louis Bornwasser (Member # 3063) on 01-10-2013, 03:33 PM:

An ohmmeter measures impedance at DC; the speaker impedance is at 1000 cycles. they are 8 ohm speakers. louis

Posted by Richard May (Member # 2627) on 01-10-2013, 04:26 PM:

Yep. 8 Ohm. We just replaced 16 of them.

Posted by Jeremy Weigel (Member # 4208) on 01-10-2013, 08:40 PM:

quote: Louis Bornwasser
An ohmmeter measures impedance at DC; the speaker impedance is at 1000 cycles. they are 8 ohm speakers.

A little confused now. I've always been told you can measure the impedance of a speaker with an ohm meter. And they are usually really close to stated rating; within a few hundredths, certainly not by half.

A little more info on the speaker. They are BA A70T's with a stamped overall rating of 6 ohms and a sensitivity of 90dB. This stamped on the upper right corner of the cabinet face. I get a measurement of 5.89 ohms with my meter. [Confused]

Posted by Ron Lacheur (Member # 1126) on 01-10-2013, 09:10 PM:

They are definitely 8 Ohm.

The DC resistance you have measured lines up with standard 8 ohm drivers, which usually is around 5.5 to 6.3ohms, but can be as high as 8.