Resisting the resistance factors?

[msrance]

Hello Friends, I got this new idea when I was replying to a post in this very forum.Let me explain this to you.

When you wire the speakers in series, you connect the + terminal of one speaker to the - terminal of the next speaker. The elctricity flows through one speaker, and then on to the speaker.This increases the total resistance, reducing the total acoustical ouput. That is, because the electricity has to flow through each speaker one at a time, each speaker adds it's resistance to the whole. The formula is as follows:

Speaker 1 + Speaker 2 = Total Ohms Rating
8 Ohms + 8 Ohms = 16 Ohms


when you wire the speakers in parallel it reduces the total resistance increasing the total output. That is, because electricity flows through all of the speakers simultaneously, each speaker added reduces the resistance of the chain. If you visualize all of the negative electrons on one side trying to get to the other, they'll have an easier time because there are so many possible paths for them to go by.

Resistance = 1 / (1/speaker 1 + 1/speaker 2)
Resistance = 1 / (1 / 8 Ohms + 1 / 8 Ohms)
Resistance = 1 / (2/8)
Resistance = 1 / .25
Resistance = 4 Ohms


Now comes my querry :

1. The A and B speaker connections in an Amp are series or parallel conection?

2. What if I was to connect the 2 speakers in the A pair in series and the speakers in B pair also in series and put the two pairs in parallel?

3. You know some thing that brings the final value closer to 8 Ohms - compared to my present value of closer to 2.


Now let me tell you why this whole train of thought. I have a 100 W/C yamaha Amp @ 8 Ohms (capable of supposedly handling 4 and 2 ohms).
My A pair of speakers : I connect both pairs(L + R) of positive and negative terminals to the active subwoofer 100W @ 4ohm from where one connection goes to each of the pair (L + R) of 80 W @ 4 ohms speakers.
My B pair of speakers: each of the terminals goes to its respective 120 W @ 8 ohms speakers.

I believe at present this combines to give an impedence of 2.67 ohms approx. If I could rewire the whole bunch to get it as close to 8 ohms as possible. Thanks for the help in advance. I am also cross posting this in the DIY and tweaks section of the forum.

[Kursun]

* Most amplifiers are wired for parallel connection. You can check this easily. Unwire one pair of speakers and set speaker selector to A+B. If wired series, you will get no sound at all. If you do get sound, the connection is parallel.

* You shouldn't wire speakers for the sake of impedance correction. Speakers wired in series is not desirable as speakers will interact with each other.

* If you have an active subwoofer its input impedance is probably not less than 1000 Ohms. So an active sub is not much of a load at the amplifier's speaker terminals. A typical active sub has about 1K impedance at speaker level inputs and about 10K impedance at its line-level inputs. The 4 Ohm impedance you're mentioning is probably the impedance of the driver of your sub. But this is handled by the internal amplifier of the active sub and is of no concern to your main amp.

[msrance]

* Most amplifiers are wired for parallel connection. You can check this easily. Unwire one pair of speakers and set speaker selector to A+B. If wired series, you will get no sound at all. If you do get sound, the connection is parallel.

The Amp connectors for Speakers A and B are in parallel. I realised that soon after asking the silly question - but then I was always pretty weak in my physics and I hated electricity all the more.

* You shouldn't wire speakers for the sake of impedance correction. Speakers wired in series is not desirable as speakers will interact with each other.

You have a great point there kursun. I had started loosing sight of the final goal in search for a mathematically correct solution.

* If you have an active subwoofer its input impedance is probably not less than 1000 Ohms. So an active sub is not much of a load at the amplifier's speaker terminals. A typical active sub has about 1K impedance at speaker level inputs and about 10K impedance at its line-level inputs. The 4 Ohm impedance you're mentioning is probably the impedance of the driver of your sub. But this is handled by the internal amplifier of the active sub and is of no concern to your main amp.

yes, I was mentioning the driver's impedence - which is of no significance in this equation as you now explain to me.

Alright, Now the basic silly question. I had asked in the forum why my amp was sounding harsh after 6 months of use (yamaha AX596)?

My assumption was the HF Driver was failing (tweeter damage) - but i was suggested that it could be because of either hearing loss (which I ruled out being a doctor myself) or secondly because of gradual amp damage because of low impedence load on the amp.

So I started going by the second suggestion - losing sight of the original reason - why is the amp sounding harsh? could it actually be a tweeter damage or amp damage (certainly not ear damage - I even underwent a Pure tone audiometry)?

Thanks.

[Kursun]

I believe it's highly unlikely that your amplifier is damaged. BTW your amplifier is capable of handling 4 ohm loads (in fact even 2 ohm loads!). It seems to have excellent dynamic behavior and high current handling capability. (http://www.yamaha-audio.co.uk/pdfs/manuals/AX596.pdf) I don't think 2.7 ohm will kill it. You may also try headphones to reassure yourself that the problem is not with the amplifier.

You may check the speakers:
1) Tweeter voice-coils may have gotten deformed if they have received more than their share of power, especially in case of the amplifier clipping. Unfortunately this is not easy to check, unlike checking scraping woofers...
2) Checking the loudspeakers crossover network is also a good idea. Either a faulty capacitor or burned out attenuator resistors on the tweeter or mid-range driver line is a possibility.

[skeptic]

Hello Friends, I got this new idea when I was replying to a post in this very forum.Let me explain this to you.

When you wire the speakers in series, you connect the + terminal of one speaker to the - terminal of the next speaker. The elctricity flows through one speaker, and then on to the speaker.This increases the total resistance, reducing the total acoustical ouput. That is, because the electricity has to flow through each speaker one at a time, each speaker adds it's resistance to the whole. The formula is as follows:

Speaker 1 + Speaker 2 = Total Ohms Rating
8 Ohms + 8 Ohms = 16 Ohms


when you wire the speakers in parallel it reduces the total resistance increasing the total output. That is, because electricity flows through all of the speakers simultaneously, each speaker added reduces the resistance of the chain. If you visualize all of the negative electrons on one side trying to get to the other, they'll have an easier time because there are so many possible paths for them to go by.

Resistance = 1 / (1/speaker 1 + 1/speaker 2)
Resistance = 1 / (1 / 8 Ohms + 1 / 8 Ohms)
Resistance = 1 / (2/8)
Resistance = 1 / .25
Resistance = 4 Ohms


Now comes my querry :

1. The A and B speaker connections in an Amp are series or parallel conection?

2. What if I was to connect the 2 speakers in the A pair in series and the speakers in B pair also in series and put the two pairs in parallel?

3. You know some thing that brings the final value closer to 8 Ohms - compared to my present value of closer to 2.


Now let me tell you why this whole train of thought. I have a 100 W/C yamaha Amp @ 8 Ohms (capable of supposedly handling 4 and 2 ohms).
My A pair of speakers : I connect both pairs(L + R) of positive and negative terminals to the active subwoofer 100W @ 4ohm from where one connection goes to each of the pair (L + R) of 80 W @ 4 ohms speakers.
My B pair of speakers: each of the terminals goes to its respective 120 W @ 8 ohms speakers.

I believe at present this combines to give an impedence of 2.67 ohms approx. If I could rewire the whole bunch to get it as close to 8 ohms as possible. Thanks for the help in advance. I am also cross posting this in the DIY and tweaks section of the forum.

When you connect one pair to the A amplifier output and one pair to the B amplifier output, the speakers are wired in parallel. However, the B speaker output may have an internal resistor in series with it to protect the amplifier from seeing too low a combined load. You would have to check either the schematic or physically examine the amplifier to determine this.

I am not sure I understand what you are saying. Are the A speakers rated at 4 ohms each? In this case you have a very low impedence load on your amplifier 1/R = 1/4 + 1/(8+?). Even if the subwoofer does not have its own amplifier, it does not mean connecting a pair of 8 ohm speakers to it make it the equivalent 4 ohm load for the main speakers + subwoofer alone. Electrically, the subwoofer has two 8 ohm voice coils which are electrially separate. Also in between the input connections and the output connections of the subwoofer is a crossover network. Not only does this network channel very low frequencies to the subwoofer and higher frequencies to the main speakers, but the subwoofer is only 8 ohms at very low frequencies and a much higher impedence at higher frequencies. Likewise the impedence of the part of the network consisting of the main speakers and the crossover elements in the subwoofer is only 8 ohms at higher than the crossover frequency and much higher below that so the combined impedence of the subwoofer/main combination is still 8 ohms per channel if your main speakers are 8 ohms. Therefore the combined impedence the amplifier sees for both pairs and the subwoofer is 4 + ? ohms, well within the capability of your amplifer.

It is not likely that the amplifier is damaged. Damage to a power amplifier usually has symptoms of no output at all, very reduced output often with a bad hum or very reduced output with high distortion. This is not what you reported. If there is a problem, it is most likely damage to the speaker possibly the tweeter.

I am very happy to know that you have not damaged your hearing. Speakers are replaceable, good hearing is not.

[msrance]

When you connect one pair to the A amplifier output and one pair to the B amplifier output, the speakers are wired in parallel. However, the B speaker output may have an internal resistor in series with it to protect the amplifier from seeing too low a combined load. You would have to check either the schematic or physically examine the amplifier to determine this.

I am not sure I understand what you are saying. Are the A speakers rated at 4 ohms each? In this case you have a very low impedence load on your amplifier 1/R = 1/4 + 1/(8+?). Even if the subwoofer does not have its own amplifier, it does not mean connecting a pair of 8 ohm speakers to it make it the equivalent 4 ohm load for the main speakers + subwoofer alone. Electrically, the subwoofer has two 8 ohm voice coils which are electrially separate. Also in between the input connections and the output connections of the subwoofer is a crossover network. Not only does this network channel very low frequencies to the subwoofer and higher frequencies to the main speakers, but the subwoofer is only 8 ohms at very low frequencies and a much higher impedence at higher frequencies. Likewise the impedence of the part of the network consisting of the main speakers and the crossover elements in the subwoofer is only 8 ohms at higher than the crossover frequency and much higher below that so the combined impedence of the subwoofer/main combination is still 8 ohms per channel if your main speakers are 8 ohms. Therefore the combined impedence the amplifier sees for both pairs and the subwoofer is 4 + ? ohms, well within the capability of your amplifer.

It is not likely that the amplifier is damaged. Damage to a power amplifier usually has symptoms of no output at all, very reduced output often with a bad hum or very reduced output with high distortion. This is not what you reported. If there is a problem, it is most likely damage to the speaker possibly the tweeter.

I am very happy to know that you have not damaged your hearing. Speakers are replaceable, good hearing is not.

Thanks for the explanation Skeptic. I too had my doubts about the tweeters.

I am sorry I couldnt explain clearly what sort of a setup was I running, if only I could draw and attach an illustration of what I mean.

And thanks again for being concerned about my hearing loss !!