Is Denon Correct About This?

[John Lohmann]

A "Tier 2" engineer I have made contact with at Denon/Marantz said some things that kind of go against a few standards I always thought were gospel (with regard to AVRs and impedance/sensitivity). Primarily:

Low sensitivity makes it difficult to drive. Low impedance actually makes it much easier to drive. But you have to be careful because the increase in power going to lower impedance speakers can be dangerous if it suddenly becomes too much power.

And:

Yeah. This is a common misconception. Regardless of which setting you choose the receiver is going to present the same amount of power, but lower impedance speakers will be able to use more of it. The 8, 6 and 4 Ohm setting is just there to tell the receiver what to expect. It does change how some of the power handled, but I am not clear on exactly what is different. I just know the same amount of power is available either way, but if you do use the recommended setting with lower Ohm rated speakers you are less likely to have the unit over heat and suffer potential damage as a result.

And:

If all of your speakers are 8 Ohms, then you can safely ignore this setting. If even one of them is 6 or 4, then you should be using it.

I was under the impression -- and someone please correct me if I'm wrong -- that low impedance makes a speaker MORE DIFFICULT to drive, not easier, as he suggested. With regard to the ohm settings, he provided that response after I asked about always keeping an amp/AVR on 8 ohms regardless of what's connected -- he's claiming that it's a misconception that AVRs should always be kept at 8 ohms (if selectable) so they always put out the most power. I was always under the impression that setting should ALWAYS be 8 ohms, but he's saying if ONE of my speakers are 6 or 4 (which none are, as far as I am aware), that ohm selector should definitely be taken OFF 8...

Any thoughts on this?

 

[Verdinut]

A "Tier 2" engineer I have made contact with at Denon/Marantz said some things that kind of go against a few standards I always thought were gospel (with regard to AVRs and impedance/sensitivity). Primarily:

Low sensitivity makes it difficult to drive. Low impedance actually makes it much easier to drive. But you have to be careful because the increase in power going to lower impedance speakers can be dangerous if it suddenly becomes too much power.

And:

Yeah. This is a common misconception. Regardless of which setting you choose the receiver is going to present the same amount of power, but lower impedance speakers will be able to use more of it. The 8, 6 and 4 Ohm setting is just there to tell the receiver what to expect. It does change how some of the power handled, but I am not clear on exactly what is different. I just know the same amount of power is available either way, but if you do use the recommended setting with lower Ohm rated speakers you are less likely to have the unit over heat and suffer potential damage as a result.

And:

If all of your speakers are 8 Ohms, then you can safely ignore this setting. If even one of them is 6 or 4, then you should be using it.

I was under the impression -- and someone please correct me if I'm wrong -- that low impedance makes a speaker MORE DIFFICULT to drive, not easier, as he suggested. With regard to the ohm settings, he provided that response after I asked about always keeping an amp/AVR on 8 ohms regardless of what's connected -- he's claiming that it's a misconception that AVRs should always be kept at 8 ohms (if selectable) so they always put out the most power. I was always under the impression that setting should ALWAYS be 8 ohms, but he's saying if ONE of my speakers are 6 or 4 (which none are, as far as I am aware), that ohm selector should definitely be taken OFF 8...

Any thoughts on this?

Have a look at the info contained in this link:

Setting the A/V Receiver Impedance Selector Switch

This article explores the purpose and function of the impedance switch found on some A/V receivers. Tradeoffs of following manufacturers recommended settings are also discussed. YouTube video inside.

www.audioholics.com

 

[John Lohmann]

Thanks, Verdi.

 

[lovinthehd]

A "Tier 2" engineer I have made contact with at Denon/Marantz said some things that kind of go against a few standards I always thought were gospel (with regard to AVRs and impedance/sensitivity). Primarily:

Low sensitivity makes it difficult to drive. Low impedance actually makes it much easier to drive. But you have to be careful because the increase in power going to lower impedance speakers can be dangerous if it suddenly becomes too much power.

And:

Yeah. This is a common misconception. Regardless of which setting you choose the receiver is going to present the same amount of power, but lower impedance speakers will be able to use more of it. The 8, 6 and 4 Ohm setting is just there to tell the receiver what to expect. It does change how some of the power handled, but I am not clear on exactly what is different. I just know the same amount of power is available either way, but if you do use the recommended setting with lower Ohm rated speakers you are less likely to have the unit over heat and suffer potential damage as a result.

And:

If all of your speakers are 8 Ohms, then you can safely ignore this setting. If even one of them is 6 or 4, then you should be using it.

I was under the impression -- and someone please correct me if I'm wrong -- that low impedance makes a speaker MORE DIFFICULT to drive, not easier, as he suggested. With regard to the ohm settings, he provided that response after I asked about always keeping an amp/AVR on 8 ohms regardless of what's connected -- he's claiming that it's a misconception that AVRs should always be kept at 8 ohms (if selectable) so they always put out the most power. I was always under the impression that setting should ALWAYS be 8 ohms, but he's saying if ONE of my speakers are 6 or 4 (which none are, as far as I am aware), that ohm selector should definitely be taken OFF 8...

Any thoughts on this?

I think your "engineer" is out of his league.

 

[Mike Up]

Sounds more like a call center drone.

Ohms law, low imedance will draw higher current. High current draw is harder on receivers and why there are separate power amplifiers. Impedance switch lowers the rail voltage, so less current is needed. In the end a large power cut from the rated per channel power output. These are called Nannys that Gene likes to talk about.

Low sensitivity speakers ~ 85db to 86db 1 watt/1 meter and/or low impedance speakers, 4 ohm, are hard to drive to loud levels for most receivers.

My Polk TL1s are right around 85 db in room while polk rated them at 89 db. I only have them in my smaller media room as main speakers. I do use them in both my main and media center theater systems for surround speakers. They are tiny, 2-1/2" woofer and 1/2" soft tweeter.

 

[John Lohmann]

Sounds more like a call center drone.

He isn't, I'm sure, but I appreciate your input. I concur that some of what he said didn't really add up; just wanted to know if anyone else felt the same way.

 

[PENG]

He isn't, I'm sure, but I appreciate your input. I concur that some of what he said didn't really add up; just wanted to know if anyone else felt the same way.

He's right about certain things he said but wrong, or at least confusing, in others. Overall no big deal, probably good and useful enough to some, but might also confuse some Denon AVR owners, depending on their EE knowledge level.

 

[highfigh]

A "Tier 2" engineer I have made contact with at Denon/Marantz said some things that kind of go against a few standards I always thought were gospel (with regard to AVRs and impedance/sensitivity). Primarily:

Low sensitivity makes it difficult to drive. Low impedance actually makes it much easier to drive. But you have to be careful because the increase in power going to lower impedance speakers can be dangerous if it suddenly becomes too much power.

And:

Yeah. This is a common misconception. Regardless of which setting you choose the receiver is going to present the same amount of power, but lower impedance speakers will be able to use more of it. The 8, 6 and 4 Ohm setting is just there to tell the receiver what to expect. It does change how some of the power handled, but I am not clear on exactly what is different. I just know the same amount of power is available either way, but if you do use the recommended setting with lower Ohm rated speakers you are less likely to have the unit over heat and suffer potential damage as a result.

And:

If all of your speakers are 8 Ohms, then you can safely ignore this setting. If even one of them is 6 or 4, then you should be using it.

I was under the impression -- and someone please correct me if I'm wrong -- that low impedance makes a speaker MORE DIFFICULT to drive, not easier, as he suggested. With regard to the ohm settings, he provided that response after I asked about always keeping an amp/AVR on 8 ohms regardless of what's connected -- he's claiming that it's a misconception that AVRs should always be kept at 8 ohms (if selectable) so they always put out the most power. I was always under the impression that setting should ALWAYS be 8 ohms, but he's saying if ONE of my speakers are 6 or 4 (which none are, as far as I am aware), that ohm selector should definitely be taken OFF 8...

Any thoughts on this?

What makes you think he's an actual engineer?

 

[John Lohmann]

He's right about certain things he said but wrong, or at least confusing, in others. Overall no big deal, probably good and useful enough to some, but might also confuse some Denon AVR owners, depending on their EE knowledge level.

Certainly didn't mean to confuse any Denon owners or anyone else for that matter; was just looking for confirmation because his input seemed contradictory to everything I've ever read about certain aspects of ohms and sensitivity.

 

[John Lohmann]

What makes you think he's an actual engineer?

My inquiry was stepped up beyond consumer level assistance to what Denon called a "Tier 2 Engineer," and some of the things he was saying in response to certain questions I had -- beyond the ohms and sensitivity aspects -- wouldn't have been easily known by a customer service rep at the basic consumer level. I could just tell; there was no way he could have answered certain queries the way he did without some kind of significant knowledge about how these machines operate.

At any rate, I'm just going to sleep soundly continuing to think that lower sensitivity speakers are more difficult to drive, as are those with lower nominal ohm ratings.

 

[PENG]

Certainly didn't mean to confuse any Denon owners or anyone else for that matter; was just looking for confirmation because his input seemed contradictory to everything I've ever read about certain aspects of ohms and sensitivity.

Again, he's not right about everything, but "seemed contradictory to everything" you've ever read about? That also don't seem right. For example, he said "Low sensitivity makes it difficult to drive. Low impedance actually makes it much easier to drive. But you have to be careful because the increase in power going to lower impedance speakers can be dangerous if it suddenly becomes too much power. "

that's mostly correct, except the highlighted part, while not exactly wrong, is certainly confusing. It is not exactly wrong because lower impedance means more current for the same voltage, so it is easier as long as the amplifier has the ability to deliver the current.

He is also right about "This is a common misconception. " Those who know me electronically, will know that I have made similar points in the past.

Technically speaking, he was mostly correct in what he said. If there is a specific part he stated that you have trouble understanding, or agreeing to, let me know and may be I can help.

If it is about 4 ohm nominal vs 8 ohm nominal, then of course on all else being equal basis the 4 ohm load would draw twice as much current, but if you lower the voltage to maintain the same current, then the amp could actually see less power draw.

 

[j_garcia]

To what Peng said, the issue being that if the amp/AVR can't deliver the power for a 4 Ohm load at a given SPL, you are more likely to actually encounter an issue like frying a tweeter. The issue is not the low impedance speaker, it is the choice of amplification that is the problem. Explaining that to people in simple terms is harder than just to say that low impedance speakers are technically harder to drive.

Low SENSITIVITY speakers are a different animal. They also need more power to achieve higher SPL.

 

[John Lohmann]

Again, he's not right about everything, but "seemed contradictory to everything" you've ever read about? That also don't seem right.

What I meant by that was I have read, during my tenure in this hobby, that AVRs and amps should always be set to 8 ohms, regardless of situation, and that low sensitivity speakers are difficult to drive -- it SEEMED, as I read his replies, that what he was saying was somewhat in contradiction to what is often offered in these forums. That's all. I didn't mean to confuse anyone or elicit any wrinkled feathers.

For example, he said "Low sensitivity makes it difficult to drive. Low impedance actually makes it much easier to drive. But you have to be careful because the increase in power going to lower impedance speakers can be dangerous if it suddenly becomes too much power. "

that's mostly correct, except the highlighted part, while not exactly wrong, is certainly confusing. It is not exactly wrong because lower impedance means more current for the same voltage, so it is easier as long as the amplifier has the ability to deliver the current.

He is also right about "This is a common misconception. " Those who know me electronically, will know that I have made similar points in the past.

Okay, well I don't personally KNOW you, electronically, so my apologies; I was merely trying to wrap my head around whether it was true that every system should be set to 8 ohms, regardless of what ohm speakers are connected, or not.

Technically speaking, he was mostly correct in what he said. If there is a specific part he stated that you have trouble understanding, or agreeing to, let me know and may be I can help.

If it is about 4 ohm nominal vs 8 ohm nominal, then of course on all else being equal basis the 4 ohm load would draw twice as much current, but if you lower the voltage to maintain the same current, then the amp could actually see less power draw.

Without getting too technical, what I wanted to know was:

1. Should an AVR, as equipped with such a selector, always be set to 8 ohms even if speakers connected are of less ohm value

and

2. Are lower-sensitivity speakers actually a bit more difficult to drive?

 

[John Lohmann]

To what Peng said, the issue being that if the amp/AVR can't deliver the power for a 4 Ohm load at a given SPL, you are more likely to actually encounter an issue like frying a tweeter. The issue is not the low impedance speaker, it is the choice of amplification that is the problem. Explaining that to people in simple terms is harder than just to say that low impedance speakers are technically harder to drive.

In the end, I didn't mean for it to get so "in the weeds;" I suppose the thread has run its course. You mentioned "explaining that to people in simple terms is harder than just...." but it's been my experience that most folks in forums like this often say "Just leave the AVR on 8 ohms, no matter what," which is why some confusion seeped in (even though I didn't intend there to be).

Low SENSITIVITY speakers are a different animal. They also need more power to achieve higher SPL.

Thanks for the confirmation.

 

[PENG]

What I meant by that was I have read, during my tenure in this hobby, that AVRs and amps should always be set to 8 ohms, regardless of situation, and that low sensitivity speakers are difficult to drive -- it SEEMED, as I read his replies, that what he was saying was somewhat in contradiction to what is often offered in these forums. That's all. I didn't mean to confuse anyone or elicit any wrinkled feathers.



Okay, well I don't personally KNOW you, electronically, so my apologies; I was merely trying to wrap my head around whether it was true that every system should be set to 8 ohms, regardless of what ohm speakers are connected, or not.



Without getting too technical, what I wanted to know was:

1. Should an AVR, as equipped with such a selector, always be set to 8 ohms even if speakers connected are of less ohm value

and

2. Are lower-sensitivity speakers actually a bit more difficult to drive?

1. Not always, it depends.
2. Yes.

It is almost bed time here but I will get back to you tomorrow with better explanation and try using a numerical example or 2, that would hopefully not get too technical.

 

[PENG]

Here's an example:

One of the 3 speakers listed below has the so called nominal impedance of 4 ohms, but which one is more "difficult" to drive?

MA speakers	impedance	Sensitivity	Handling	Recommended	Max SPL
Radius 90	8	83	75	30-100	102
Gold on wall 6G	4	88	150	130-300	115
KEF
LS50	8	85		40-100	106

In this case, I would say the 8 ohm rated Monitor Audio Radius 90 is likely more "difficult" to drive if you want to get say 102 dB peak at 1 meter with 1 speaker.

A Numerical example based on the specs of the speakers above:

Radius 90:
With 1 W, at 1 meter, peak SPL = 86 dB
Gold on wall 6G, at 1 meter, speak SPL = 88 dB Note: For this calculation using online calculators, I have to enter 85 dB sensitivity instead of the 88 dB specified because 2.83V, 4 ohms >2 W, not 1 W.

Above is based on over simplification @John Lohmann don't want it to get too technical, so in practice the real conclusions may be a little, or quite different.

In practice, we also have to consider the following:
- Impedance vs frequency curve, not just a simple "nominal impedance" number.
- Actually bench test verified sensitivity, not just the specified one, as manufacturers often inflated that number.
- Phase angle vs frequency, large phase angles means more heat dissipation in the output stage of class AB amplifiers so on all else being equal basis, speakers that have poorer phase angle vs frequency are harder to drive (not because of higher current demand).

That Denon "engineer" is right in the narrow sense that lower impedance (think resistance, literally, to avoid getting technical) implies less resistive to the driving force, in this case, the applied voltage.

There is no easy to understand analogy that I can think of, but may be consider it is easier to push a 50 lb weight than a 200 lb weight on a wood floor, the 50 lb weight should be easy to push if you just want to move it, but if you have to move it at very high speed, then it could be more difficult to move it than to move the much heavier weight at very low speed.

So, hard to drive, as the Denon "engineer" stated, might in fact be a common "misconception", but he could have worded it to something less confusing, such as "a matter of perspective", making it sound like an open ended issue...

Now, a little technical:
Bottom line, it has a lot to do with the "power", "watts" being used, or misused from day one, when it would have been better to reference to voltage and current instead off power. Yes it is simpler to just use "power", but the fact is, one needs to understand that the so called "high current" amp for low impedance load will lead to confusion, as an low impedance load may also need "high voltage" depending on a few factors, and how do we define "high current amp"? Many have stated that high current amp means amp that could "double down to 4 and then 4 ohms", that's a poor and impractical definition, based on "common misconceptions"? Who know?

I am not trying to defend the Denon gentleman, in fact the way he expressed himself could confuse a lot of Denon AVR owners. It is also apparent that most 4 ohm nominal rated speakers tend to require power amplifiers that have robust power supplies that are neither voltage nor current limited, again on all else being equal basis. Take a look of some popular British designed speakers such as B&W, KEF, Monitor Audio, their high end products tend to have nominal 4 ohms impedance while their lower end products are 8 ohm nominal, while their sensitivity specs don't differ that much, mostly between mid 80's to 90 dB/2.83V. So in such cases, it is almost true to say that their 4 ohm speakers are harder to drive.

It is just that it cannot be generalized, because ultimately, sensitivity (among others, such as power handling specs, max. SPL) is a better indicator to drawing a conclusion, than using impedance in isolation.

 

[highfigh]

My inquiry was stepped up beyond consumer level assistance to what Denon called a "Tier 2 Engineer," and some of the things he was saying in response to certain questions I had -- beyond the ohms and sensitivity aspects -- wouldn't have been easily known by a customer service rep at the basic consumer level. I could just tell; there was no way he could have answered certain queries the way he did without some kind of significant knowledge about how these machines operate.

At any rate, I'm just going to sleep soundly continuing to think that lower sensitivity speakers are more difficult to drive, as are those with lower nominal ohm ratings.

That's 'tier 2 technical support', engineers work in the engineering department at the factory or headquarters. I have been a Denon dealer for a long time and have access to dealer support, but don't remember being in contact with any engineers. The first tier people should know about impedance- it's one of the areas where they NEED to know this but it doesn't need to go to the level of phase angle, capacitive/inductive reactance and other more technical stuff because those are for tweaky people.

Sensitivity is simply the output SPL (Sound Pressure Level) that results from sending a signal at 2.83VAC into the speaker. Power is a calculated value, found by using the Ohm's Law formula P=E²/R which, at 8 Ohms becomes P=(2.83)²/8. 2.83 x 2.83 = 8.0089, which is close enough for practical purposes and if that's divided by 8, it's about 1.001 Watts.

The only effect of using lower sensitivity speakers- more power is needed to reach any output level but for system design purposes, it does matter if high output is required because a low power amplifier won't be adequate.