What is the best method to reverse engineer a woofer to a subwoofer enclosure. I am working on a subwoofer for my SIL. It is a 10" Bohlender Graebener Z sub. The voice coil rubs, and the cone has disconnected from the VC. My choices are; Try to find used replacement sub or driver. Have the driver repaired. Find a new compatible/equivalent replacement to fit the enclosure. I am thinking the 3rd option would be the easiest to source once I determine the requirements. The dimensions of the interior of the cabinet are;
14-3/4" Deep x 15-3/4" High x 11" Wide. It has a ~3-3/8" diameter x 9" long port.
Interior volume is taken up by a brace, the woofer, the amplifier & the port. The gross volume is ~1.4 cubic feet. After subtracting the brace, woofer amp & port the interior volume is ~.75 cubic feet.
Since I don't know the impedance of the woofer, I will go out on a limb and say it is 4 ohms. The amplifier looks A/B and pretty beefy based on the transformer.
BTW the woofer has what may be a part# (10P32) and date code (20030430D) if anyone can tell by this where to find a replacement. It has a stamped steel basket and a vented pole piece.
14-3/4" Deep x 15-3/4" High x 11" Wide. It has a ~3-3/8" diameter x 9" long port.
Interior volume is taken up by a brace, the woofer, the amplifier & the port. The gross volume is ~1.4 cubic feet. After subtracting the brace, woofer amp & port the interior volume is ~.75 cubic feet.
Since I don't know the impedance of the woofer, I will go out on a limb and say it is 4 ohms. The amplifier looks A/B and pretty beefy based on the transformer.
BTW the woofer has what may be a part# (10P32) and date code (20030430D) if anyone can tell by this where to find a replacement. It has a stamped steel basket and a vented pole piece.
The option to buy a new woofer probably is the cheapest option indeed.
You know the cabinet volume and port dimensions. The missing information is what equalization built in the amplifier. You could check that by measuring the transfer function of the amplifier. Next, plug this information in WinISD and simulate some randomly chosen woofers. As it is a vented enclosure, the woofer is likely to have Qts in the range of 0.3 - 0.5.
To estimate the woofers impedance, measure the rail voltages of the amplifier. The amplifier should deliver 150 Wrms, which is 300 W peak. For example, say you measure rail voltages of +40 V and -40 V. Under load this will sag to about +35 V and -35 V. This will result in 153 W peak in 8 ohms, 204 W peak in 6 ohms or 306 W peak in 4 ohms.
This ad says its 8 ohms. https://www.ebay.com/itm/125556217796
You know the cabinet volume and port dimensions. The missing information is what equalization built in the amplifier. You could check that by measuring the transfer function of the amplifier. Next, plug this information in WinISD and simulate some randomly chosen woofers. As it is a vented enclosure, the woofer is likely to have Qts in the range of 0.3 - 0.5.
To estimate the woofers impedance, measure the rail voltages of the amplifier. The amplifier should deliver 150 Wrms, which is 300 W peak. For example, say you measure rail voltages of +40 V and -40 V. Under load this will sag to about +35 V and -35 V. This will result in 153 W peak in 8 ohms, 204 W peak in 6 ohms or 306 W peak in 4 ohms.
This ad says its 8 ohms. https://www.ebay.com/itm/125556217796
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