I am looking at some S/H and cheap woofers simply because they are cheap and as toys to play with.
Seller doesn't have any data
Can anybody here help with data on some old subwoofer drivers from Accusound.
So far the only info is a picture of a sticker on the drivers magnet EX - 15-2 -16R
But at $60- a driver I'm not expecting much. Not picking them up until next month so looking at sims etc before then
Hard paper cone, pressed steel basket and the folded "W" surround typical of Pro-sound gear
Seller doesn't have any data
Can anybody here help with data on some old subwoofer drivers from Accusound.
So far the only info is a picture of a sticker on the drivers magnet EX - 15-2 -16R
But at $60- a driver I'm not expecting much. Not picking them up until next month so looking at sims etc before then
Hard paper cone, pressed steel basket and the folded "W" surround typical of Pro-sound gear
One place where you can find data and procedures for DIYing your own T/S measurements on a speaker is the ancient Radio Shack Advanced Speaker Systems soft copy booklet by Ray Alden.
Measurement only requires 1) an audio signal source, available online, to play through your computer, tablet or phone, 2) a Fast Fourier audio spectrum analyzer program you can use with that same computer, 3) a $6 Digital Multi Meter, 4) a few resistors you can carefully calibrate with that same Multi Meter and 5) several coins, whose weights meet published Govt Standards.
Low value resistors, below 100 Ohms, can be measured using the 4-terminal Kelvin technique, where a known current is passed through the resistor being measured, then the Voltage is measured across it, using Ohm's Law to calculate its resistance. The Kelvin technique removes the effect of DMM test lead resistance.
In desperation, even lower value, but fragile, 1 to 10 Ohm resistors can be made from graphite pencil leads. Steel binder notebook spirals make excellent resistors in the tens-to-hundreds of milliOhms.
Measurement only requires 1) an audio signal source, available online, to play through your computer, tablet or phone, 2) a Fast Fourier audio spectrum analyzer program you can use with that same computer, 3) a $6 Digital Multi Meter, 4) a few resistors you can carefully calibrate with that same Multi Meter and 5) several coins, whose weights meet published Govt Standards.
Low value resistors, below 100 Ohms, can be measured using the 4-terminal Kelvin technique, where a known current is passed through the resistor being measured, then the Voltage is measured across it, using Ohm's Law to calculate its resistance. The Kelvin technique removes the effect of DMM test lead resistance.
In desperation, even lower value, but fragile, 1 to 10 Ohm resistors can be made from graphite pencil leads. Steel binder notebook spirals make excellent resistors in the tens-to-hundreds of milliOhms.
I'll measure them when I receive them but I was looking for and hoping for specs before hand so I can start putting aside box materials etc.
I'd possibly use them OB too if they were suitable.
The main reason I am looking at these apart from being a big woofer junkie is the cheap selling price, so I'm not expecting to get a Rolls-Royce driver
I'd possibly use them OB too if they were suitable.
The main reason I am looking at these apart from being a big woofer junkie is the cheap selling price, so I'm not expecting to get a Rolls-Royce driver
Interesting, just did a search and 'White Van' speaker threads popped up! If true, not worth measuring, just put them in at least a 3 ft^3 box tuned to 40 Hz if like the ones hawked in my locale decades ago.
GM has the right idea. If you can find specs without any work, that's always the best way, unless you're fixated on testing.
A notebook spiral made a nice sense resistor when I checked the current from my 14V supply into my SUV's battery. 2 years ago, I bought several battery monitors. They're still in their boxes and I'm still using the kluges.
Using the Dayton woofer tester takes a couple of minutes so no biggie.
I was toying with the idea of making another quad box a metre a side and 600 deep and wired in parallel, wheels and handles naturally.
I was toying with the idea of making another quad box a metre a side and 600 deep and wired in parallel, wheels and handles naturally.
I lost my camera yesterday; spent an hour looking for it in the shed; came inside and it was sitting on my keyboard where I'd left it.
OK
I just put one of my old 15" woofers on the bench and used the little test set-up.
I had 4 of these in a quad box based on the size of a standard pallet because I got a shipping box free.
If the cheap ones are anything like it I'll be happy enough at $60- each as these are waiting to be refoamed at $24- a foam ring
With a Qts of 1.28 and a Vas of 211 litres they would seem to be a better candidate for an infinite or open baffle than a ported box and I can no longer remember what size port I used but the box was 1200 x 1000 and about 600mm deep so about 720 litres. All I can say is that it was both loud and deep.
Hoping for something similar but better as the pictures of the sale drivers seems to have much bigger magnets than these El-Cheapo woofers.
I'll measure these again when I've done the new surrounds
I just put one of my old 15" woofers on the bench and used the little test set-up.
I had 4 of these in a quad box based on the size of a standard pallet because I got a shipping box free.
If the cheap ones are anything like it I'll be happy enough at $60- each as these are waiting to be refoamed at $24- a foam ring
With a Qts of 1.28 and a Vas of 211 litres they would seem to be a better candidate for an infinite or open baffle than a ported box and I can no longer remember what size port I used but the box was 1200 x 1000 and about 600mm deep so about 720 litres. All I can say is that it was both loud and deep.
Hoping for something similar but better as the pictures of the sale drivers seems to have much bigger magnets than these El-Cheapo woofers.
I'll measure these again when I've done the new surrounds
