I got two pairs of 4-Ohm woofers: ADS S10. I’m planning for their wiring configuration. The only way I could think is to wire them in series to make the impedance to about 8 Ohms. However, I realize that connecting woofers in series have no advantages. But it’s not recommended to wire them in parallel as well since the impedance would be too low; 2 Ohms. So, what should be done to these woofers? Are there any creative ways to implement? I mean using series crossover network with the woofers connected in parallel, or vice versa.
Why would you think that?
Some advantages that I can think of:
- Higher impedance, easier load for the amp
- You get +3 dB efficiency in the bass region compared to one driver
- You get double the power rating, eventually even a bit more regarding the Xmax limitation compared to one driver
- doubled inductance
- -3dB sensitivity compared to one 4 ohm driver (but still +3dB efficiency)
From what I’ve read, series connection doesn’t give +3dB but 0dB. Only parallel connection will give +6dB.
For power handling and Xmax, I agree with you. But my system isn’t that huge powered system. It’s just driven by an ordinary integrated amplifier and used in the bedroom.
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You are speaking of sensitivity but I was mentioning efficiency.
Anyhow, I was wrong about reduced sensitivity of series woofers! Sorry about that!
You're not wrong. Compared to a single unit & assuming a regular contemporary voltage source amplifier:
Short version: you can wire two nominal 4ohm units in series. There are plenty of designs that do just that. Providing they are within reasonable tolerance of each other, there shouldn't be any issues.
- Series wiring = +3dB for doubled cone area & -3dB for halved current draw from the amplifier for a net 0dB nominal difference in sensitivity
- Parallel wiring = +3dB for doubled cone area & +3dB for the doubled current draw from the amplifier for a net +6dB nominal increase in sensitivity.
Short version: you can wire two nominal 4ohm units in series. There are plenty of designs that do just that. Providing they are within reasonable tolerance of each other, there shouldn't be any issues.
Well, it's still good to have a few replies to the questions.
Here are the alternative options generated from what my brain can imagine.
A. conventional parallel connection
B. conventional parallel .5 ways system
C. alternative parallel .5 ways system
D. conventional series connection
E. alternative series connection - I'm not sure if it could be considered as a typical 3rd-order crossover.
So, could anyone help to figure out pros and cons for these configurations? And which choice is recommended to my case? (I prefer not too low impedance, but increasing SPL is favorable, as my amplifier is a mid-fi gear--Braun A1--and used in a small bedroom)
PS. Addition of other innovative ways is welcomed.
Here are the alternative options generated from what my brain can imagine.
A. conventional parallel connection
B. conventional parallel .5 ways system
C. alternative parallel .5 ways system
D. conventional series connection
E. alternative series connection - I'm not sure if it could be considered as a typical 3rd-order crossover.
So, could anyone help to figure out pros and cons for these configurations? And which choice is recommended to my case? (I prefer not too low impedance, but increasing SPL is favorable, as my amplifier is a mid-fi gear--Braun A1--and used in a small bedroom)
PS. Addition of other innovative ways is welcomed.
Depends specifically on what you're trying to achieve. From the published data a single unit is nominally 88.4dB [nearly] 1m/w & more relevantly 91.8dB 1m/2.83v under IB conditions so it's not a particularly inefficient driver. A pair wired in series therefore retains its 91.8dB 1m/2.83v sensitivity rating, while the 1m/w efficiency rating rises to 91.4dB. Assuming a small space with a relatively close listening position & modest SPLs I doubt your amplifier will run out of headroom. It's far more likely to struggle with a 2ohm or < impedance.
yes, electrically it is a 3rd order connection.
considering eventual driver-inherent spl and impedance response curves the actual slopes may change quite a lot.
also keep in mind that the layout you chose has the same results as the "classic" 3rd order layout (order of series components does not matter, at least in this hgh current case):
Interesting woofers. Very low Fs, Qts, and huge Vas
How you wire depends on the amplifier. If it is 2Ω capable you are OK with parallel, if not wire in series (something i have not been shy to do), and keep in mind that if you move it on, most people won’t have 2Ω capable amps.
dave
How you wire depends on the amplifier. If it is 2Ω capable you are OK with parallel, if not wire in series (something i have not been shy to do), and keep in mind that if you move it on, most people won’t have 2Ω capable amps.
dave
Curt Campbell's "Tritrix MTM" design would be one of the best known speakers with 4 ohm drivers wired in series. He uses the Dayton DC130BS-4, which is more efficient than the 8 ohm version so that the series connection has good efficiency, but gives a benign impedance to the receiver/amp.
They sound great for the modest money.
Geoff
They sound great for the modest money.
Geoff
So, in a normal three-way design, I should be connecting the woofers as shown in figure D, am I correct?
However, what if I go for .5 way configuration, how to implement the .5 ways with "series" connection?
I mean for connecting woofers in parallel, it can be achieved by using figures B or C, but what about connecting the woofers in series?
However, what if I go for .5 way configuration, how to implement the .5 ways with "series" connection?
I mean for connecting woofers in parallel, it can be achieved by using figures B or C, but what about connecting the woofers in series?