I just acquired an old 10" powered Optimus subwoofer from a customer of mine and it is in perfect shape. I want to beef it up a bit with some bracing on the cabinet and a better driver. The problem is that I can't find info on the driver or the amp. The amp says it is 120 watts RMS, but I can only assume that is into an 8 ohm load. There is no indication anywhere on the driver that it is an 8 ohm driver, and I want to be sure. It would be great if this amp could handle a 4 ohm load to give me a bit more power if I used a 4 ohm sub.
Anybody know where I can find information on this subwoofer? The model number is PRO SW-10P.
Thanks
Anybody know where I can find information on this subwoofer? The model number is PRO SW-10P.
Thanks
To check out the driver you can just use a DMM to measure resistance. If it measures about 6ohm, then you have an 8ohm driver, and if it measures out at 3ohm, then you have a 4ohm driver.
You should do as Pinkmouse says. However, since you said it was a powered sub, I would be surprised if it was anything but a 4 ohm driver.
The popular sub crossover/amp combos all work best into 4 ohms. Check out the sub crossover/amps at Madisound or Parts Express to confirm. From what I can gather, there are only one or two manufacturers, and everyone gets their crossover/amp combos from them and has their labels put on. Both manufacturers, (if there are two), put out into 4 ohms primarily. Those crossover/amp combos are now pretty universal-everyone uses them except the real High End manufacturers.
But by all means, check the DC resistance across the terminals. It's certainly a quick enough test to perform. 🙂
As for Thiele-Small specs, I would ignore the old driver's specs and merely measure or estimate the internal volume of the sub enclosure, then find a nice sub driver to fit from the usual sources.
Good luck!
The popular sub crossover/amp combos all work best into 4 ohms. Check out the sub crossover/amps at Madisound or Parts Express to confirm. From what I can gather, there are only one or two manufacturers, and everyone gets their crossover/amp combos from them and has their labels put on. Both manufacturers, (if there are two), put out into 4 ohms primarily. Those crossover/amp combos are now pretty universal-everyone uses them except the real High End manufacturers.
But by all means, check the DC resistance across the terminals. It's certainly a quick enough test to perform. 🙂
As for Thiele-Small specs, I would ignore the old driver's specs and merely measure or estimate the internal volume of the sub enclosure, then find a nice sub driver to fit from the usual sources.
Good luck!
Guess who just happened to have an old Radio shack catalog, heh, heh.
The part number for your sub, (printed on the unit, I am sure), is 40-5030. The retail price, (though it was often on sale), was $199.50.
Going to www.radioshack.com, clicking "Product Manuals" at the top, and putting 40-5030 in the "Search" box, we arrive with 3 manuals, one of which turns out to be the 9 page owners manual. That is located here:
http://support.radioshack.com/support_audio/doc65/65829.pdf
Page 8 of the Owner's Manual reveals the following info-it's 100 Watts into 4 Ohms:
Amplifier Output .....120W RMS (4 Ohms @ 10% THD)
100W RMS (4 Ohms @ 1% THD)
Crossover .....50 Hz–200 Hz Adjustable
Frequency Response .....44–200 Hz
Power Voltage ....AC 120 V/60 Hz
Power Consumption ....50W
Dimensions (HWD) .....15 9/16 ´ 14 ´ 17 3/8 (395.3 ´ 355.6 441.3 mm)
Weight .....31 lbs (14 kg)
I am not sure how the power output can be 100 Watts but the "Power Consumption" can be 50 Watts, but what the heck. I am not engineer.
As far as internal volume, I subtracted an inch from one dimension to allow for the grill cloth and frame, assumed 1" building material all around, and came up with an internal volume of approx 1.35 cu ft. If they used 3/4" building material, then you have a little extra volume, but not enough to throw off any box calculations by much.
Box strengthening? A cubelike box is probably fairly rigid anyway, but the speaker cutout should allow you sufficient room to put in braces for the interior walls.
Good luck!
The part number for your sub, (printed on the unit, I am sure), is 40-5030. The retail price, (though it was often on sale), was $199.50.
Going to www.radioshack.com, clicking "Product Manuals" at the top, and putting 40-5030 in the "Search" box, we arrive with 3 manuals, one of which turns out to be the 9 page owners manual. That is located here:
http://support.radioshack.com/support_audio/doc65/65829.pdf
Page 8 of the Owner's Manual reveals the following info-it's 100 Watts into 4 Ohms:
Amplifier Output .....120W RMS (4 Ohms @ 10% THD)
100W RMS (4 Ohms @ 1% THD)
Crossover .....50 Hz–200 Hz Adjustable
Frequency Response .....44–200 Hz
Power Voltage ....AC 120 V/60 Hz
Power Consumption ....50W
Dimensions (HWD) .....15 9/16 ´ 14 ´ 17 3/8 (395.3 ´ 355.6 441.3 mm)
Weight .....31 lbs (14 kg)
I am not sure how the power output can be 100 Watts but the "Power Consumption" can be 50 Watts, but what the heck. I am not engineer.
As far as internal volume, I subtracted an inch from one dimension to allow for the grill cloth and frame, assumed 1" building material all around, and came up with an internal volume of approx 1.35 cu ft. If they used 3/4" building material, then you have a little extra volume, but not enough to throw off any box calculations by much.
Box strengthening? A cubelike box is probably fairly rigid anyway, but the speaker cutout should allow you sufficient room to put in braces for the interior walls.
Good luck!
How's that for luck!
Well, I'm actually not sure what I might do for bracing the cabinet, because, as you said, it is fairly strong already, but I might just connect opposing sides with wooden dowels or something. It already had glue blocks on the corners, so it.s fairly stable.
When I popped the driver out I realized that it has a surprisingly large downfiring port that almost reaches the top of the cabinet. I think I'm going to take out the port and seal the hole, and then maybe put in a good quality car audio subwoofer and see how it sounds. Listening to it for an hour or so last night made me realize that it is a pretty decent sounding sub, it just has a major problem going very low at all. I have a Polk EX subwoofer from a few years ago that I have always loved the sound of. I might put that in there and see how it does. I happen to know that it is capable of going very deep for a 10 inch driver.
I'm also gonna have to see if I can get this Optimus logo off of the grill cloth. 😉
Well, I'm actually not sure what I might do for bracing the cabinet, because, as you said, it is fairly strong already, but I might just connect opposing sides with wooden dowels or something. It already had glue blocks on the corners, so it.s fairly stable.
When I popped the driver out I realized that it has a surprisingly large downfiring port that almost reaches the top of the cabinet. I think I'm going to take out the port and seal the hole, and then maybe put in a good quality car audio subwoofer and see how it sounds. Listening to it for an hour or so last night made me realize that it is a pretty decent sounding sub, it just has a major problem going very low at all. I have a Polk EX subwoofer from a few years ago that I have always loved the sound of. I might put that in there and see how it does. I happen to know that it is capable of going very deep for a 10 inch driver.
I'm also gonna have to see if I can get this Optimus logo off of the grill cloth. 😉
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