Speakers in series - capacitor

[Harald Kapp]

In my case the z2300 has those on its pcb,

In that case no additional capacitors or inductor are required.

So one of the speakers is playing the full range of signal and the other above 1200Hz? or both play above 1200Hz?

Which of the several diagrams in this thread do you refer to?

I know that the z2300 amp has a low pass filter of 150Hz, I am assuming I still need the cap, so my question is how big should the cap be not to impede the signal of <200Hz?

Depends on the characteristics of the speakers and the amplifier output. I cannot give you a general rule, sorry.

 

[cero10]

Kalimera Cero:
1 and 2) These are LC filters. The basic LC filter equation is of not much use as the other components including the frequency dependent impedance of the speakers have to be accounted for. The design of crossover filters for well sounding speakers is a little science per se (see for example here)
3) No. A potentiometer is a voltage divider, ideally independent of frequency. A filter like this is a frequency divider, ideally independent of voltage.
4) What do you mean by that? If well designed the impedance as "seen" by the amplifier is the same as for a single speaker.

1) Will red through it.
3) He has a LPF what does he need the frequency divider for?

Hello,
Here is an article from ESP for the calculation needed for passive cross over filters:
https://sound-au.com/lr-passive.htm

Bertus

I will read it when I free up some time, thanks. In case I do not find a cap with a specific capacitance in my area, is it safe to add multiple caps in series/parallel to get the capacitance I need?

 

[bertus]

Hello,

When the Z2300 has active filters, you do not need external filters.
Can you post a picture of the Z2300 board, top and bottom?

Bertus

 

[cero10]

In that case no additional capacitors or inductor are required.

1) Which of the several diagrams in this thread do you refer to?

2) Depends on the characteristics of the speakers and the amplifier output. I cannot give you a general rule, sorry.

First of all are you greek?
1)I am talking about this one.
2) for a single channel parallel bridge 100W amp at 8ohm and <1% THD

Bertus in this project you said "Req en Ce make a correction for the impedance of the low speaker." what do you mean?

Hello,

When the Z2300 has active filters, you do not need external filters.
Can you post a picture of the Z2300 board, top and bottom?

Bertus

Yes give me some time. But I do not think those are logitech z2300.

 

[Harald Kapp]

No, I'm not Greek. Learned some Greek for my vacations in Crete .
1) The speaker bypassed by the capacitor is for the midtones mainly as high frequencies will be shunted by the capacitor. The speaker without capacitor in parallel is for the full range. Full range here means the range that is fed to the speakers behind the crossover on the amplifier PCB, therefore midtones and high tones only. As to the frequency: There will not be a sharp cutoff at any frequency, but a gradual decline. Usually one defines the cutoff frequency of a filter where the amplitude falls by 3 dB, but the curve (amplitude vs. frequency) is smooth, not a sharp edge.
2) Still insufficient information. Usually the amplifier may be designe to drive 8 Ω speakers, but the amplifier's output impedance is much lower to allow good damping of the speakers. The speakers themselves cannot be characterized by the impedance alone. The impedance varies with frequency as does the efficiency for converting the electrical signal to an acoustic signal. Speakers are commonly characterized by so called Thiele/Small parameters and there's a bunch of theory and math behind these and their correct use to build speakers.

3) He has a LPF what does he need the frequency divider for?

Probably not only a low pass for the bass but also a high pass for the midtones and highs. These filters are "frequency dividers". They divide the full spectrum into a low range and a mid/high range to operate each type of speaker in the best suited range.

is it safe to add multiple caps in series/parallel to get the capacitance I need?

Read here.

 

[cero10]

No, I'm not Greek. Learned some Greek for my vacations in Crete .
1) The speaker bypassed by the capacitor is for the midtones mainly as high frequencies will be shunted by the capacitor. The speaker without capacitor in parallel is for the full range. Full range here means the range that is fed to the speakers behind the crossover on the amplifier PCB, therefore midtones and high tones only. As to the frequency: There will not be a sharp cutoff at any frequency, but a gradual decline. Usually one defines the cutoff frequency of a filter where the amplitude falls by 3 dB, but the curve (amplitude vs. frequency) is smooth, not a sharp edge.
2) Still insufficient information. Usually the amplifier may be designe to drive 8 Ω speakers, but the amplifier's output impedance is much lower to allow good damping of the speakers. The speakers themselves cannot be characterized by the impedance alone. The impedance varies with frequency as does the efficiency for converting the electrical signal to an acoustic signal. Speakers are commonly characterized by so called Thiele/Small parameters and there's a bunch of theory and math behind these and their correct use to build speakers.


Probably not only a low pass for the bass but also a high pass for the midtones and highs. These filters are "frequency dividers". They divide the full spectrum into a low range and a mid/high range to operate each type of speaker in the best suited range.


Read here.

Nice! Which towns did u visit?
1) perfect I understand now.
2) I guess that is way over my head then, lets leave it at that

Just making sure we are talking about the same thing. In this setup the frequency divider only applies to the midrange F5s right?

Also do passive crossovers consume power?

 

[Harald Kapp]

What you marked is a volltage divider to match impedances.
The crossover (frequency divider ) is the part C1/L1 and C2/L3.
At a crossover frequency of 4000 Hz (this circuit) F5 will reproduce low to mid tones, SD1.1 reproduces mid to high tones.

Also do passive crossovers consume power?

Yes. Ideally very lottle, but they do.

 

[cero10]

Hello,

When the Z2300 has active filters, you do not need external filters.
Can you post a picture of the Z2300 board, top and bottom?

Bertus

Here are the links to the front of the pcb: 111 222 333 444
Can not get to the back, the 15-pin is glued to the heat sink.

What you marked is a volltage divider to match impedances.
The crossover (frequency divider ) is the part C1/L1 and C2/L3.
At a crossover frequency of 4000 Hz (this circuit) F5 will reproduce low to mid tones, SD1.1 reproduces mid to high tones.

Yes. Ideally very lottle, but they do.

Ok so this is the LC you were talking about, I am guessing the frequency cutoff for is much steeper than just connecting a cap in parallel to a speaker.
As the z2300 amp has a build-in crossover, do I still need the caps in series with the satellites+subwoofer?

 

[Harald Kapp]

do I still need the caps in series with the satellites+subwoofer?

Usually not, but I don't know for sure as I don't know the amplifier and I guess nobody here can unless he/she has a schematic of an original design. Even then a definitive answer probably cannot be given as the final sound depends on the speakers you use, the construction of the speaker cabinet, the filters that are (or are not) present etc.
As I said, designing a well sounding speaker is not trivial. You may have to build the complete speaker with cabinet etc. and listen to the sound it produces. If you are not satisfied, experiment with different filters/capacitances, other speakers or modification of the cabinet.

 

[Audioguru]

You have a subwoofer with a crossover at 150Hz and you have tiny tweeters but you do not have a woofer/midrange speaker for frequencies in between.
So maybe the 8" speaker is a single-channel woofer and has a crossover at 2kHz and the tweeters are ordinary little 2.5" speakers, not tweeters and have a 2kHz crossover.