So, does a 4-ohm speaker play louder than an 8-ohm speaker with the same amplifier and volume setting?
It's entirely dependent on speaker's sensitivity and output level, which is usually measured at 1 m.
On the other hand, an amplifier will output more power with lower impedance.
Here's the output of Hypex NC400:
580 watts at 2 ohms
400 watts at 4 ohms
200 watts at 8 ohms
If you were to measure a speaker with DC you'd get a resistance. If you were to measure it with AC at various frequencies, you'd get impedance.
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Harriet, thank you for that info.
I must say the Townshend F1 speaker cable is the best I have ever tried/owned, and I have tried alot, perhaps it is because of the impedance network built into the cable?
ozzy
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Yes Ozzy, this is the micro-site for the Townshend F1 and Isolda Speaker cables. Max tried to understand the clear differences he heard when hearing matched impedance cables Vs unmatched impedance cable.
Dedicated to understanding the phenomenon and spending a large chunk of his last years researching and testing.
His videos on You Tube called 'Geometry Matters' charts his reasoning.
Harriet
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townshend-audio,
Is that the same for the F1 speaker cable?
ozzy
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At Townshend Audio we match the average nominal speaker impedance (around 8oHms) with the impedance of the amplifier using Isolda 'impedance matched' Speaker Cable. Here we explore the reasoning behind our cable products: https://townshendcable.com/
Our Analysis uses a test set-up to prove how mismatched speaker cables will cause audible differences between a range of cables.
Thanks for your time.
Harriet Townshend
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jjss49, erik_squires,
Thanks for that very good information. It’s interesting and confusing at the same time.
ozzy
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Lower impedance = higher current = more output. Since most solid state amplifiers can drive 4 Ohms without issue as a speaker designer I might chose a lower impedance driver to give me more output. Especially in matching say a woofer to tweeter, when tweeters usually have more output for the same voltage.
AFAIK there's no actual standard for rating your speakers, and some like modern KEF speakers, are so optimistic in rating their speakers that you can't use them to pick matching amps at all.
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But if 8 ohms is optimum then why are there so many 4-ohm speakers? I put together a DIY speaker a while back and I was able to use all 8-ohm speakers. So, the drivers are out there.
impedance of a speaker is one of many design parameters that speaker designers trade off in very complicated ways
think of speaker impedance very roughly as how much work an amp needs to do.... you can put in a few simple drivers and a minimal crossover in an undamped box, and the amp will have a super easy time doing the work, but how will it sound? (if this were so easy, we would all have speakers like this...) - but easy to drive, simple lightweight drivers will distort when pushed and don’t have broad, controlled, flat frequency response (they shout, they ring, they break up...)
so the designer uses more robust drivers, and more of them, then this complicates the crossover and cabinet design, all of which makes for more work for the amp... more stuff to grip, to stop and start, to deliver current into (how the amp does the work...)
so the designer says, well, mister speaker owner, you want better super clean sound, full range response, plenty of power handling to play loud AND clean... so i have had to do all this to my speaker design -- include all these well damped drivers, put in a well tuned box, match them all, filter them all superbly with a complicated crossover -- to give you the performance you want... but hey now, you gotta use a strong amp to do the work to get that sound...
whenever i see 3 way tower speakers with 3-4-5-6 drivers, multiple woofers, think of an amp needing to grip it all (think big focals, magico, thiels)... there is alot of work to do (compared to say a single driver speaker) so you can bet the impedance will be lower... not to mention the efficiency
tradeoffs....
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esarhaddon1,
So, what number(s) are meaningful when it comes to speaker specs?
Is this what you mean by a Zobel Network?
RLC network to prevent unstable amplifiers from oscillating, to reduce distortion, and to act as an RF filter
ozzy
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Loosely translated into Layman's language it is the impedance at any given frequency. And of course Impedance is roughly (improperly) equivalent to resistance. Most speakers , as the sound frequency approaches its resonant frequency, the impedance starts to spike. I have had many people ask why I use what is called a 'ZOBEL' network in my crossovers, and this is the reason. A Zobel network tries to compensate for that spike and lets the speaker operate more uniformly at lower frequencies. And be careful when Ozzy says it is just a number. It is but it is a very important number when designing a crossover.
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So, I guess I understand that now, nominal impedance is just a number. Highly questionable, I guess that is so with sensitivity ratings. Different frequencies produce different amounts of energy, so that could be all over the map in reality.
But if 8 ohms is optimum then why are there so many 4-ohm speakers? I put together a DIY speaker a while back and I was able to use all 8-ohm speakers. So, the drivers are out there.
And companies like Rockport, Wilson, etc. claim to make their own drivers, but they design them with lower ohms. Why?
ozzy
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Nominal impedance means blah blah blah blah, meh...that said, Almarg was one of the reasons I bought a Pass XA-25. A cool guy who's missed around here.
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I was just reading a review of the Rockport Orion speakers in The Absolute Sound by Robert Harley.
They weigh about 350lbs! Cost over $133,000 and it is still a 4-ohm speaker!
ozzy
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amir_asr, Thank you for that info. I wonder though if most tube type amps would also show a large amount of distortion?
BTW, I like the sound of the Carver amps. Previously I owned Atmasphere, Pass, Krell and a few others.
ozzy |
Given that it is 8 ohm speaker….Y
Bent
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OOps. Post the 8 ohm power sweep. Here is 4 ohm:
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@ozzy
What does Nominal Impedance mean?
I’m trying to decide on some new speakers (Clarisys Minute). They are rated at 86-88 sensitivity and a nominal impedance of 3.5 flat. Although graphs show it about 6 ohms from 20hz-500hz and at 2Khz and above about 3 ohms.
Turns out you don't need to know what Nominal Impedance is in this case as your speaker has essentially flat response of 3.5 to 4.2 ohm (based on youtube measurement of it). Normal speakers have wildly varying impedance with frequency so no one number ever represents its impedance. Your speaker is then is an easy load for most amplifiers.
Better yet, I have tested your Carver 350 amplifier with 4 ohm load. Here is its frequency response:
The amplifier has a peaking response with this type of load so may sound a bit bright.
You do have a ton of power available:
And even more for short periods:
So you can crank it up good, assuming the copious amount of distortion is not bothersome to you. In that regard, you are going to hear more of that distortion than your current, more sensitive speakers.
If you like, I can measure your new speakers. Start a conversation with me and we can take it from there. Good luck.
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@ozzy Wrote:
So, does that mean they will play louder or does the amp need to work harder? ozzy
Both! Also the lower the impedance the amp operates in, the higher the distortion produced by the amp.
Mike
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So, does that mean they will play louder or does the amp need to work harder?
ozzy |
@ozzyWrote:
Let me ask another question:
So, does a 4-ohm speaker play louder than an 8-ohm speaker with the same amplifier and volume setting?
As I understand, only in 8 Ohm load does 2.83 volts produce 1 watt. In a 4 Ohm load 2.83 volts produces 2 watts. 😎
Mike
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Agree to @jjss49
Nominal impedance shows exactly nothing.
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So, does a 4-ohm speaker play louder than an 8-ohm speaker with the same amplifier and volume setting?
no, depends on speaker sensitivity
and more broadly, i believe nominal impedance is basically a useless measure
speaker makers don't use the same standards and pretty much write anything into their marketing literature - always always looks at the whole impedance curve
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What Mapman said. he nails it.
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Let me ask another question:
So, does a 4-ohm speaker play louder than an 8-ohm speaker with the same amplifier and volume setting?
ozzy
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@clearthinker Wrote:
This poor manufacturer behaviour is mirrored by not quoting a dB range when specifying low frequency extension, and by over-stating sensitivity, which occurs very often.
(Proper) measurements matter.
I agree 110%! See the manual below of my speakers, it's the most comprehensive speaker manual of specifications I known of. They even explain how they arrive at their numbers. See last page specifications:
Mike
https://www.lansingheritage.org/html/jbl/specs/pro-speakers/1984-4430-35.htm
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ditusa,
Your explanation makes sense and seems to concur with what I read. (somewhere).
ozzy
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I vaguely remember that the speaker industry standard rating of impedance as what it is at 1000Hz. Which is kind of silly because the impedance is usually all over the place unless the speakers use series crossovers.
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@ozzy,
I think nominal impedance means the industry standard. Impedance should not fluctuate more then 8 or 9% from the standard. I.E. An 8Ohm speaker should be no less then 6Ohms, a 4Ohm speaker should be no less then 3Ohms, if they follow the standard.
Mike
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czairvey,
Wow! Interesting. Most of this is over my head. I have a business degree.
ozzy
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Impedance is a combination of linear R (resistance) and non-linear X (reactance)
A Reactance is a combination of Inductive and capacitive components. In the world of complex algebra the impedance Z is represented by = R + jX. In case of the DC, X component is null so the Impedance in this case is linear resistance R.
Inductive component impedance is known as wL where w is frequency and L is Inductance.
Capacitive component impedance is known as 1/wC where C is capacitance
Overall Z = R + j(1/wC + wL) where j is directional vector
Notably, with increase of frequency Inductive component increases while capacitive component decreases. that means that on DC capacitor will have an infinite impedance and Inductor will act like short circuit.
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Incidentally I have never seen a speaker whose impedence measures a flat 2.5-3 ohms over 100-10k Hz. Have you?
I have the Thiel 3.6's. From Stereophile:
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@ozzy it is rare that a large cabinet speaker is also not sensitive. The reason for the large cabinet is to increase its efficiency and thereby sensitivity. Small speakers are typically more difficult to drive and require greater power to overcome their lack of sensitivity and low impedance curves. Ohm’s law explains these electrical properties but I suspect it will be a little over your head unless you intend to do a deep dive into the subject.
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I know this is a complicated subject & not as simple as this but the primary way to get decent, extended, deep bass that can play relatively loudly from smaller woofers ( less than 8” or so) is to have 2 or more of them usually wired in parallel which lowers the effective impedance ( the reciprocal of the sum of the reciprocals).
The taller, narrow baffle designs popular now for the sake of theoretically better imaging lends itself to smaller woofers if the cabinet cost is to remain reasonable & not “sculpted” in some way. many new speakers today have pretty low impedance & thus their actual effective sensitivity is lower than stated.
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ditusa,
Probably, but many large speaker cabinet types still have low impedance and sensitivity requiring monster amps to drive them.
ozzy
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@ozzy Wrote:
Wonder why companies just don’t make speakers that are 8+ ohm and with high sensitivity? But it seems to be just the opposite, that is; many of the big-name speaker manufacturers produce speakers that are 4-ohm and low sensitivity.
Wonder why that is?
ozzy
Maybe Hofmann's iron law is one of the reason. Article
Mike
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lak,
Yes, I think so. Though it will be a long wait to get them, and I will probably have to rob a bank...
ozzy
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@ozzy, are you getting the Clarisys Audio Minuet Neodymium speakers?
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@gs5556 How right you are!
'Nominal impedence' is generally concocted by a speaker manufacturer to hide elements of his speaker's impedence curve that he would rather hide. It has no basis whatsoever in physics. Responsible manufacturers show the full curve for impedence vs. frequency and the phase angle at audio frequencies, because bad combinations of impedence and phase angle can often occur making a speaker tougher to drive than could be apprehended from the impedance curve alone.
Incidentally I have never seen a speaker whose impedence measures a flat 2.5-3 ohms over 100-10k Hz. Have you?
This poor manufacturer behaviour is mirrored by not quoting a dB range when specifying low frequency extension, and by over-stating sensitivity, which occurs very often.
(Proper) measurements matter.
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Nominal means "in name only" and has little to do with the actual impedance of the speaker. That’s why it’s confusing. The speaker impedance is measured across the frequency band and someone at the speaker company looks at it and says hmmm... that looks like about 6 ohmsish on average so we’ll call these 6-ohm speakers.
This is one area where published specs are important. I look at the impedance curve of my speakers and they are a flat 2.5 to 3 ohms from 100hz to 10kHz which tells me I need a hefty solid state amplifier for the low impedance but a tube amp with a 3 ohm output tap would work great also since the impedance is flat.
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michaellent, randym860,
Well, that’s what I think, but sometimes you just never know how different components interact.
Still, it is so confusing trying to figure out the importance of speaker sensitivity and impedance when it comes to speakers.
Wonder why companies just don’t make speakers that are 8+ ohm and with high sensitivity? But it seems to be just the opposite, that is; many of the big-name speaker manufacturers produce speakers that are 4-ohm and low sensitivity.
Wonder why that is?
ozzy
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There are not many speakers those amps won't drive.
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You could drive a car with those amps! +300W
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+ another @milpai almarg is the one poster who could immediately answer any question! And I agree with @dweller nominal in this sense means average,
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+1 @milpai, To say he had a way with words is an understatement. Being a copyright lawyer (among other things) he was concise, succinct and a joy to read.
All the best,
Nonoise
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Jim Clark from Carver just replied to my email saying that the Carver amps would have no problem driving the speaker based on the specs in this posting. But I wish he had provided more detail.
Here is his reply,
"The nominal impedance is an average of the impedance curve. Many speakers vary between 2 and 20 ohms at various frequencies. Your 350's should have no problem driving them. Enjoy! Thanks, Jim"
ozzy
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With all due respect to people who chimed in, I do miss "almarg" on such topics.
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