Is this speaker crossover OK?

Thread Starter

bloguetronica

Joined Apr 27, 2007
1,541
This is a crossover for the "Taurus" project. These are intended to be mid-end and relatively cheap speakers. However it is my wish to submit it here too for a final revision. My questions are?

Are the values OK?

Is the phase shift of 180º between the woofer and the tweeter correctly assumed (note the tweeter "polarity" reversal when compared to the woofer)?

C1/3 – Capacitor Visaton ELKO spez. 3,3µF;
C2 – Capacitor Visaton ELKO spez. 15µF;
C4 – Capacitor Visaton ELKO spez. 6.8µF;
FTE1 – Tweeter Visaton SC 10 N 8 OHM;
FTE2 – Woofer Visaton SC 13 8 OHM;
J – RCA plug;
L1-3 – Coil Visaton SP 0,47mH 0,6mm;
R1 – 6,8Ω carbon resistor (5% tol., 1W);
R2 – 10Ω carbon resistor (5% tol., 2W).

You can see the schematic diagram in the attached PDF file.

I really need a third opinion on this. Thanks in advance.
 

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R!f@@

Joined Apr 2, 2009
9,918
U know what I think of passive crossovers. It's nothing.
But since you cannot go about building active crossovers, here is my opinion
First is that passive crossovers are standardized for a particular speaker and numerous testing is done in an test room for proper phase alignment and all the anomalies that are introduced due to passive crossovers
So if you are testing by your ears then you are not gonna hear any difference unless the signal is played in stereo mode.
Only in stereo mode phase cancellatiobn creates dips in the sound.
Point is that if you are not using a pair but just a woofer and a tweeter than phase shift is not much of a problem to the human ears.
But an active crossover can really change you view towards crossovers.

Rifaa

 

Audioguru

Joined Dec 20, 2007
11,248
The little 5" midrange speaker does not have much bass.
I couldn't find a datasheet for the tweeter to see if it is at the same level.

Inverting one speaker to make them in phase results in a +3dB boost at the crossover frequency.
 

Thread Starter

bloguetronica

Joined Apr 27, 2007
1,541
The little 5" midrange speaker does not have much bass.
I couldn't find a datasheet for the tweeter to see if it is at the same level
Both of them have a sensitivity of 90dB. Here is the "datasheet" for the tweeter:
http://www.visaton.de/en/chassis_zubehoer/geschirmt/sc10n_8.html

About the bass, there is not much to do. A good and well tuned enclosure will minimize that. The frequency response is measured in free air.

Inverting one speaker to make them in phase results in a +3dB boost at the crossover frequency.
Indeed, since it is a Butterworth filter. So the speakers are oriented correctly, right? I just need to confirm if the phase shift is 180º between both speakers, which seems a bit odd in a second order crossover.
 

Thread Starter

bloguetronica

Joined Apr 27, 2007
1,541
Just came to the conclusion that the series notch filter is not necessary. R1, L2 and C2 were taken out. Other components were renamed.

C1/2 – Capacitor Visaton ELKO spez. 3.3µF;
C3 – Capacitor Visaton ELKO spez. 10µF;
FTE1 – Tweeter Visaton SC 10 N 8 OHM;
FTE2 – Woofer Visaton SC 13 8 OHM;
J – RCA plug;
L1/2 – Coil Visaton SP 0,47mH 0,6mm;
R – 8.2Ω wirewound resistor (5% tol., 3W).

You can see the new schematic diagram in the attached file.
 

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Audioguru

Joined Dec 20, 2007
11,248
You are making an even-order Butterworth crossover filter that produces a +3dB peak at the crossover frequency. You should use a Linkwitz-Riley crossover filter circuit instead that does not have the peak. It uses Bessel filters instead of Butterworth.
Here is a Linkwitz-Riley active crossover circuit: http://www.sound.westhost.com/project81.htm

You should use an 8 inch woofer for much better and deeper bass.
 

Thread Starter

bloguetronica

Joined Apr 27, 2007
1,541
You are making an even-order Butterworth crossover filter that produces a +3dB peak at the crossover frequency. You should use a Linkwitz-Riley crossover filter circuit instead that does not have the peak. It uses Bessel filters instead of Butterworth.
Here is a Linkwitz-Riley active crossover circuit: http://www.sound.westhost.com/project81.htm
Thanks! I corrected that, and now I use a Bessel crossover.
 
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