2. speakers
  3. 167506-151430

Chained speakers signal connected in series

I have two pairs of the same model speakers (Tannoy SGM 10B) connected in series to two monoblock amplifiers. The left channel amp drives two speaker cabinets on a left (speakers L1 and L2) and the right channel amp drives two speaker cabinets on a right (speakers R1 and R2).
The positive speaker output of the left amp is connected to a positive post of the first speaker L1(+). Then the negative post of the same first speaker L1(-) is connected to positive post of the second speaker L2(+) with the its negative post L2(-) connected to the amplifier's negative speaker output.

AMP(+) > L1(+)
L1(-) > L2(+)
L2(-) > AMP(-)

Both left channel speakers have a cross-overs build in. Does the audio signal that the first speaker L1 receives from amplifier is any different from a signal the second speaker L2 receives from speaker L1? Does the crossover of the first speaker L1 modify the output signal that goes to a second speaker L2?
esputnix

Showing 4 responses by imhififan

imhififan's avatar
imhififan
2,220 posts
 
You can connect two speakers in series and it won’t harm the amplifier.
BUT because of two sets of crossover connected in series the sound it produce will be totally different from just one speaker connect to the amplifier! Both woofer in each speaker will get much lower crossover point and the tweeter will get a band-pass filter instead of high pass.
imhififan's avatar
imhififan
2,220 posts
 
I disagree with imhififan’s opinion that the crossover points will change.
I believe the Tannoy SGM 10B has parallel crossover, if connect two speakers in series, the LF section will be #1 speaker low pass inductor --> #1 speaker woofer --> #2 speaker low pass inductor --> #2 speaker woofer.
Correct me if I'm wrong, doesn't each woofer will see two inductor and a woofer voice coil in another speaker in series?
imhififan's avatar
imhififan
2,220 posts
 
@fiesta75, 
Can we agree that Rt equals 16ohms in series?
Yes
Can we agree that Lt = L1 + L2 in series?
No, IMO, the first woofer will see the voice coil of second woofer as an inductor in series, same for the second woofer, it will see the voice coil of first woofer as an inductor.
I think the total inductance should be Lt = L1 + L2 + Lvc1 + Lvc2
Can we agree that 1/Ct = 1/C1 + 1/C2 in series?
Yes
it's yes to the above, then simply plug those numbers into the equations. f = R/2πLQ and f = Q/2πRC. 
May be a crossover design simulator software can give us a better answer.

imhififan's avatar
imhififan
2,220 posts
 
@fiesta75,
I think it was 7 or 8 years ago, my friend use Hornresp (http://www.hornresp.net/) did a simulation on his speakers and found that connect two speakers in series the low pass filter cutoff frequency get lowered, our conclusion was the first woofer will see the voice coil of second woofer as an inductor in series, same for the second woofer, it will see the voice coil of first woofer as an inductor in series, and caused crossover point lower than a single woofer alone.
More to discover