Series circuit speaker design modification

[Ferroll]

Will this work? The DIY top speaker box has no crossover, so full range sound is not affected going into a Sony SSCS3 tower.

 

[lovinthehd]

Will what work? Your link in post 1 doesn't work. Some question about active crossovers or something more frankenstein?

 

[Swerd]

Will this work?

Perhaps, but who knows for how long. The tweeter in that small DIY speaker won't last long.

The DIY top speaker box has no crossover, so full range sound is not affected going into a Sony SSCS3 tower.

Why did you build a 2-way speaker without any crossover filter? Why did you hook up those two speakers that way?

 

[lovinthehd]

I think frankenstein was close....

 

[Swerd]

Perhaps, but who knows for how long. The tweeter in that small DIY speaker won't last long.

It's not at all clear that your arrangement will be an 8 ohm load to your receiver. That tweeter might survive, if your receiver fails first.

 

[TLS Guy]

Will this work? The DIY top speaker box has no crossover, so full range sound is not affected going into a Sony SSCS3 tower.

No it won't work. Impedance is NOT resistance. So apart from the arrangement being a voltage divider, each speaker will interact with an inductive load of the other. The frequency response will be horrible.

You can ONLY wire speakers in series if they are drivers, and the drivers must be identical. You can NOT wire completed speakers in series.

I have no idea why you want such a ridiculous scheme.

 

[Swerd]

I have no idea why you want such a ridiculous scheme.

I was waiting for his response when I previously asked a similar question.

I can only guess why he was concerned: He might have feared the 6Ω load of the Sony tower speakers would be too low for his receiver. So, he came up with an idea he hoped would yield 8Ω.

For any readers who wonder what this fuss is about, here's the issue. Electrical resistance occurs with direct current (DC). For a given circuit, it's a constant value. Musical signals in audio reproduction involve alternating current (AC). What matters is impedance, which varies with the frequencies in the audio signal. Even though it's expressed as a single nominal value, such as 6Ω, it really varies. A loud speaker also has an inherent DC resistance, but what matters to a receiver or amplifier is the impedance as a speaker is fed an AC signal. With DC resistance you can easily calculate a net resistance for a parallel or series circuit. With loud speakers, you cannot do that. AC impedance must be measured and plotted against frequency in a graph. Here's an example of the impedance of a 2-way speaker. I don't know what the manufacturer's impedance rating was, but I'd call that a 4Ω speaker.

 

[Ferroll]

I was waiting for his response when I previously asked a similar question.

I can only guess why he was concerned: He might have feared the 6Ω load of the Sony tower speakers would be too low for his receiver. So, he came up with an idea he hoped would yield 8Ω.

For any readers who wonder what this fuss is about, here's the issue. Electrical resistance occurs with direct current (DC). For a given circuit, it's a constant value. Musical signals in audio reproduction involve alternating current (AC). What matters is impedance, which varies with the frequencies in the audio signal. Even though it's expressed as a single nominal value, such as 6Ω, it really varies. A loud speaker also has an inherent DC resistance, but what matters to a receiver or amplifier is the impedance as a speaker is fed an AC signal. With DC resistance you can easily calculate a net resistance for a parallel or series circuit. With loud speakers, you cannot do that. AC impedance must be measured and plotted against frequency in a graph. Here's an example of the impedance of a 2-way speaker. I don't know what the manufacturer's impedance rating was, but I'd call that a 4Ω speaker.
View attachment 56611

The amp can support a 6 ohm load, but all other channels will have speakers at 8 ohms, so I thought it would be best to add the 2 ohms too the 6 ohm Sony to make 8 ohms. Since the speakers in the top box are rated at 40 watts max each, there should be no way they will be damaged by the amp Onkyo TX-NR7100 9.2 ? - 100 W/Ch (8 ohms, 20 Hz–20 kHz, 0.08% THD, 2 channels driven, FTC)
When considering the Sony SS-CS3 tower can handle a max 145 watts.

 

[Swerd]

The amp can support a 6 ohm load, but all other channels will have speakers at 8 ohms, so I thought it would be best to add the 2 ohms too the 6 ohm Sony to make 8 ohms.

Adjusting things, as you did, to 'equalize' the speakers' impedance values is not necessary at all. Most modern solid state receivers can easily handle that without you doing anything unusual.

Unless you measure the impedance of your speakers as you expose them to pink noise or a frequency sweep, you cannot predict what the total impedance will be. Because of your original post, I doubt if you have the necessary measuring gear. No harm with that – few of us actually have that gear. But don't expect that you can treat this as a typical DC circuit and add up the various resistances of those series-wired devices.

If I understand your diagram correctly, you built a small speaker with two drivers, each of which is rated as having 4 ohms impedance, and you wired them in parallel to each other. Three questions:

1. Are those two drivers identical?
2. Or are they a small woofer and tweeter?
3. Are they without a crossover?

Then you wired that smaller speaker in series with the Sony 3-way tower. Right, or wrong?

You didn't mention the make & model of the two drivers in your small speaker. The mid-woofer(s) can only go so high in frequency before they cannot go higher. Some will naturally loose response without complaining too much, but others make ugly sounding noise when they are exposed to frequencies they cannot handle. This is called woofer break-up noise. You should always use a low-pass filter that blocks those offending higher frequencies. That's one major reason why we use crossovers.

If your small speaker has a woofer and tweeter, and if you drive them without any crossover, the tweeter will distort and live a short life. Without a high-pass filter, it will be exposed to low frequencies that it was never designed to handle. That's a second major reason why we use crossovers. (There are many more reasons, but I'll stop with those two.)

Since the speakers in the top box are rated at 40 watts max each, there should be no way they will be damaged by the amp Onkyo TX-NR7100 9.2 ? - 100 W/Ch (8 ohms, 20 Hz–20 kHz, 0.08% THD, 2 channels driven, FTC)
When considering the Sony SS-CS3 tower can handle a max 145 watts.

If you meant this to explain what you did, I don't understand your reasoning.

The top box speakers can't handle power more than 40 watts without failing. The Sony tower can handle much higher power. They should be able to also get louder alone than with the added top box speakers.

1. Why limit the Sony towers?
2. Or, why expose the top box to damaging power?

Remove the top box speakers, and attach the Sony towers in the normal way. You may find they sound better without the top box. Don't worry about the difference between the 6 ohm towers and 8 ohm impedance speakers in the other channels. Your AVR should be able to take that in stride.

 

[Ferroll]

Adjusting things, as you did, to 'equalize' the speakers' impedance values is not necessary at all. Most modern solid state receivers can easily handle that without you doing anything unusual.

Unless you measure the impedance of your speakers as you expose them to pink noise or a frequency sweep, you cannot predict what the total impedance will be. Because of your original post, I doubt if you have the necessary measuring gear. No harm with that – few of us actually have that gear. But don't expect that you can treat this as a typical DC circuit and add up the various resistances of those series-wired devices.

If I understand your diagram correctly, you built a small speaker with two drivers, each of which is rated as having 4 ohms impedance, and you wired them in parallel to each other. Three questions:

1. Are those two drivers identical?
2. Or are they a small woofer and tweeter?
3. Are they without a crossover?

Then you wired that smaller speaker in series with the Sony 3-way tower. Right, or wrong?

You didn't mention the make & model of the two drivers in your small speaker. The mid-woofer(s) can only go so high in frequency before they cannot go higher. Some will naturally loose response without complaining too much, but others make ugly sounding noise when they are exposed to frequencies they cannot handle. This is called woofer break-up noise. You should always use a low-pass filter that blocks those offending higher frequencies. That's one major reason why we use crossovers.

If your small speaker has a woofer and tweeter, and if you drive them without any crossover, the tweeter will distort and live a short life. Without a high-pass filter, it will be exposed to low frequencies that it was never designed to handle. That's a second major reason why we use crossovers. (There are many more reasons, but I'll stop with those two.)
If you meant this to explain what you did, I don't understand your reasoning.

The top box speakers can't handle power more than 40 watts without failing. The Sony tower can handle much higher power. They should be able to also get louder alone than with the added top box speakers.

1. Why limit the Sony towers?
2. Or, why expose the top box to damaging power?

Remove the top box speakers, and attach the Sony towers in the normal way. You may find they sound better without the top box. Don't worry about the difference between the 6 ohm towers and 8 ohm impedance speakers in the other channels. Your AVR should be able to take that in stride.

OK, Thank you for the information. Since the Onkyo can handle a 6 ohm impedance, then I'll just use the one 6 ohm Sony with the three 8 ohm Polks. I am surprised no one mentioned adding a 100 watt 2 ohm resistor inline on the red wire going to the Sony.

 

[TLS Guy]

OK, Thank you for the information. Since the Onkyo can handle a 6 ohm impedance, then I'll just use the one 6 ohm Sony with the three 8 ohm Polks. I am surprised no one mentioned adding a 100 watt 2 ohm resistor inline on the red wire going to the Sony.

They did not mention it, as it a very stupid thing to do. That has the effect of increasing the source resistance/impedance, which will make the frequency response follow the impedance curve of the speaker. I suggest you study AC circuit design and theory. DC circuits are a totally different ball game and not applicable to other circuits.

 

[Swerd]

I am surprised no one mentioned adding a 100 watt 2 ohm resistor inline on the red wire going to the Sony.

This is using DC circuit thinking misapplied to an AC circuit. It will not achieve what you hope. TLS Guy was correct when he said it will have unintended consequences on the speaker sound that no one wants.

I've tried to communicate to you that AC electrical circuits behave quite differently than DC circuits. Understanding DC circuits at a basic level can be somewhat intuitive. When I first learned about them, they seemed easy to understand. However, AC circuits were quite different and not so easily understood. I found them counter-intuitive compared to how I thought I understood DC circuits, at first. I finally understood AC circuits better, only if I ignored my intuition and relied on the math used to describe them. Once I got that, it allowed me to see that my earlier understanding of DC circuits was over-simplified. I had ignored frequency when I first learned DC. After learning AC, I understood DC as a subset of AC – where the frequency wasn't absent, but was a constant value.

I get it if you don't want to spend time & effort at learning AC circuit design. But you should at least understand to avoid relying on somewhat simplified DC circuit thinking as a way to treat the complex interactions of audio amplifiers and loudspeakers.

 

[Audiophile Heretic]

They did not mention it, as it a very stupid thing to do. That has the effect of increasing the source resistance/impedance, which will make the frequency response follow the impedance curve of the speaker. I suggest you study AC circuit design and theory. DC circuits are a totally different ball game and not applicable to other circuits.

I think you can teach the poster about what you know without being insulting. Are you trying to drive people away from Audioholics, or audio as a hobby?

A resistor also increases resistance as it heats up, so, in addition to changing the frequency response, a resistor in series with the speaker also produces dynamic compression. The series resistor also reduces the amplifier's ability to damp the speaker, increasing ringing, muddying the transient response.

 

[Audiophile Heretic]

For any readers who wonder what this fuss is about, here's the issue. Electrical resistance occurs with direct current (DC). For a given circuit, it's a constant value. Musical signals in audio reproduction involve alternating current (AC). What matters is impedance, which varies with the frequencies in the audio signal. Even though it's expressed as a single nominal value, such as 6Ω, it really varies. A loud speaker also has an inherent DC resistance, but what matters to a receiver or amplifier is the impedance as a speaker is fed an AC signal. With DC resistance you can easily calculate a net resistance for a parallel or series circuit. With loud speakers, you cannot do that. AC impedance must be measured and plotted against frequency in a graph. Here's an example of the impedance of a 2-way speaker. I don't know what the manufacturer's impedance rating was, but I'd call that a 4Ω speaker.

Resistance occurs with DC or AC. Resistance is part of impedance. Resistance is a scalar value. Scalar values have magnitude. Simple impedance is a vector with magnitude and phase. Simple impedance is vector Z = R + jX where R = resistance, X = reactance, and j = the imaginary number √(-1). The magnitude of impedance |Z| = √(R² + X²) and the phase angle Θ = arctan(X/R). Vector Z = R + jX = |Z| (cos Θ + j sin Θ). Complex impedance varies as a function of frequency.

Vector impedance Z = resistance R when reactance X = 0 (zero). When reactance X = 0 phase angle Θ = 0.

That's more complicated than most audio enthusiasts want to digest, but to imply that electrical resistance occurs only with direct current is incorrect.

The really hard part is that music signals are many simultaneous changing frequencies, complex and aperiodic, unlike the simple swept sine wave that created your impedance graph. The current required driving a complex impedance speaker with complex music signals is not like picking a single point on the impedance graph.

 

[Audiophile Heretic]

To 'equalize' the speakers' impedance values is not necessary at all. Most modern solid state receivers can easily handle that without you doing anything unusual.

Remove the top box speakers, and attach the Sony towers in the normal way. You may find they sound better without the top box. Don't worry about the difference between the 6 ohm towers and 8 ohm impedance speakers in the other channels. Your AVR should be able to take that in stride.

This is the most import comment.

 

[Speedskater]

Actually two complete loudspeakers is series don't work that way.
See the last part of this lord helmet Pierce paper:
"Damping: Loudspeakers In Series"

http://www.cartchunk.org/audiotopics/SeriesSpeaker.pdf

 

[Audiophile Heretic]

Actually two complete loudspeakers is series don't work that way.
See the last part of this lord helmet Pierce paper:
"Damping: Loudspeakers In Series"

http://www.cartchunk.org/audiotopics/SeriesSpeaker.pdf

Thank you for the interesting article. Please correct me if I am wrong. I believe the article refers to identical speakers in series. The speakers the poster referred to are definitely not identical.

I still believe that adding an additional speaker in series just to increase the load impedance to the amplifier in this case is not only unnecessary, it is detrimental to the sound.

 

[Speedskater]

Yes, definitely 'identical speakers in series'.
But that includes identical multi-driver loudspeakers.