I was wondering if this 6" 1.5 Ohm sub driver can be used in an active DIY sub. It is from a Sony surround sound system. I have a Class D 100W amp for it, but not sure if such a low impedance driver would work.
Any reason why it shouldn't? Btw, it is a TPA3116D2 amp.
Any reason why it shouldn't? Btw, it is a TPA3116D2 amp.
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Good point! I didn't because the label on the back of the sub cabinet says 1.5 Ohms.
But I measured it now and my multimeter says 3.4Ω. So which one is more likely to be correct? I know from experience to not trust low ohm multimeter readings much. I could do a 4-wire Kelvin test to be sure, but that won't be so easy right now.
I measured on the driver terminals. It is a passive sub, i.e. there is nothing else in the cabinet.
But if you think that the 3.4Ω measurement can be trusted, then all is well.
But if you think that the 3.4Ω measurement can be trusted, then all is well.
According to the user manual, yes the model with the B at the end is indeed 1.5Ω vs 3Ω for the non-B version. Not sure why, they both seem to have that same single driver. Maybe the smart guys will step in here.
Well, thanks for your help so far. Maybe I should measure it properly.
I was donated this Sony sub today and was hoping that I can use it.
I was donated this Sony sub today and was hoping that I can use it.
You're welcome.
If it reads 3.4Ω DCR, it's a nominal 4Ω impedance. The literature on that driver backs it up.
If it reads 3.4Ω DCR, it's a nominal 4Ω impedance. The literature on that driver backs it up.
I for one do not accept the 3.4 ohm reading on first sight 🙂
Please short multimeter probes together, note reading (which will NOT be zero), measure speaker DC resistance and substract the previous value, what remains is closer to Truth 🙂
Plan B: get some power supply (old PC or even phone charger?), get a 10 to 20 ohm resistor, connect supply to speaker , measure voltage drop across resistor and across speaker coil, post results.
Speaker will thump and move forwards or backwards but no big deal, besides test takes less than a minute.
Poor man´s "Kelvin setup" 😉
Please short multimeter probes together, note reading (which will NOT be zero), measure speaker DC resistance and substract the previous value, what remains is closer to Truth 🙂
Plan B: get some power supply (old PC or even phone charger?), get a 10 to 20 ohm resistor, connect supply to speaker , measure voltage drop across resistor and across speaker coil, post results.
Speaker will thump and move forwards or backwards but no big deal, besides test takes less than a minute.
Poor man´s "Kelvin setup" 😉
Just to add to Fahey's usual smart posts, what you need is a precision resistance in the range of the driver as your standard. See what your meter reads.
When I run impedance/freq plots I always plot resistors bracketing the speaker's resistance. Sure better than blindly trusting a rather long chain of gear and assumptions.
When it comes to test gear and nuclear war treaties, trust but verify.
B.
When I run impedance/freq plots I always plot resistors bracketing the speaker's resistance. Sure better than blindly trusting a rather long chain of gear and assumptions.
When it comes to test gear and nuclear war treaties, trust but verify.
B.
Yeah, thanks. I will do a proper Kelvin test a bit later. The only way to know for sure.
@Norman Bates: I only have the one driver unfortunately.
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@Norman Bates: I only have the one driver unfortunately.
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A Kelvin 4-wire measurement reveals that it is 3.53Ω DCR.
So Cal Weldon was correct. It is 4Ω nominal. Very sneaky on Sony's part to discourage folk to re-purpose old drivers! 🙄
Thanks to everyone who chimed in.
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So Cal Weldon was correct. It is 4Ω nominal. Very sneaky on Sony's part to discourage folk to re-purpose old drivers! 🙄
Thanks to everyone who chimed in.
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Here is some feedback. The driver is working just fine powered by a Class D amp. It makes a big difference to the sound I get from my current system.
I've reinstalled the driver into the original Sony sub-woofer cabinet and connected it through a 50W TPA3116D2 amp + NE5532 low pass filter. I'll get a higher power class D amp later and mount it plate amp style into the rear of the cabinet.
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I've reinstalled the driver into the original Sony sub-woofer cabinet and connected it through a 50W TPA3116D2 amp + NE5532 low pass filter. I'll get a higher power class D amp later and mount it plate amp style into the rear of the cabinet.
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Without using a 4-wire measurement approach with your ohmmeter, it is difficult to accurately measure low resistances like that. The measurements will always err high.
Dear Nerds, it's a 4 Ohm driver used by Sony, LG, Samsung, the world, his wife, his mother and the dog.
I come across Sony subs like this at thrift shops all the time. Last year I picked up a couple to measure, out of curiosity. Not the exact same as yours but similar. The lowest DCR I've measured is 2.6 ohms. But even then, that woofer didn't dip that low in it's impedance curve. These "sub"woofers measure terribly though. High Fs(70-90hz), high Q(0.7+)
Thanks for the info. This sub will have to do for now. It sounds great, though.
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