Is Denon Correct About This?

[John Lohmann]

"engineer" of what?

You'd have to ask him; I was told he was a Denon/Marantz "Tier 2 Engineer."

 

[Verdinut]

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Tier 2: This tier handles more advanced troubleshooting, working on issues that require deeper technical knowledge than Tier 1 can provide. Tier 3: Tier 3 consists of highly specialized technicians or engineers who manage complex, system-level issues that may involve advanced configurations or development.

 

[John Lohmann]

Who cares at this point what the meaning is behind this guy's moniker? The underlying query was about if the things being said about ohms and sensitivity were true or not, and it seems that's been answered, essentially by way of a "it depends" conclusion (taking the sensitivity element out of the equation).

Here's the thing, in a proverbial nutshell:

Because you so often read about how a speaker ohm selection in a piece of electronics should always be set to 8, regardless of scenario (otherwise, the story goes, you're severely limiting power of the amplification device), I was wondering if what I was being told regarding that was accurate.

Also, it didn't seem to make sense to me what was being said regarding lower sensitivity speakers -- I was always told these are harder to drive than higher sensitivity variants.

 

[Verdinut]

Who cares at this point what the meaning is behind this guy's moniker? The underlying query was about if the things being said about ohms and sensitivity were true or not, and it seems that's been answered, essentially by way of a "it depends" conclusion (taking the sensitivity element out of the equation).

Here's the thing, in a proverbial nutshell:

Because you so often read about how a speaker ohm selection in a piece of electronics should always be set to 8, regardless of scenario (otherwise, the story goes, you're severely limiting power of the amplification device), I was wondering if what I was being told regarding that was accurate.

Also, it didn't seem to make sense to me what was being said regarding lower sensitivity speakers -- I was always told these are harder to drive than higher sensitivity variants.

No, lower sensitivity speakers require more amp power than the one with a higher sensitivity to output same SPL. But nowadays with amplifiers having more power than 75 years ago, they are rather easy to drive.

With regard to the AVR Speaker Impedance switch, I think you should read again the info in the link at post #2.

 

[John Lohmann]

No, lower sensitivity speakers require more amp power than the one with a higher sensitivity to output same SPL

So that's what I thought...

 

[dolynick]

I'm not an engineer so someone can feel free to correct me if I misspeak here.

As Peng said, Impedance is basically resistance at a given frequency. So less resistance can be interpreted as easier flow of electrons. So correct in that interpretation I guess.

When dealing with speakers, amps and volume though, sensitivity is a rating of SPL (loudness) at 1W and 1 meter away. As you increase loudness, you require more power. Power is I^2 * R (current squared times resistance). So current might flow easier through that lower impedance, but more of it is required to achieve the same power (and thus SPL/loudness) at the lower resistance.

If you're trying to put out 100W into 8 Ohms, you require ~3.5A of current from the amplifier.
If you're trying to put out 100W into 4 Ohms, you require ~5A of current from the amplifier.

Most people will interpret that behavior as being "harder" on the amplifier. Which is where the disconnect from the Denon rep's statement is.

As far as sensitivity goes, it takes double the power to increase output (SPL) by 3db. So in order to get an 83db sensitivity speaker to be the same perceived volume as an 86db speaker, you automatically need twice as much power. Perceived "twice as loud" is an increase of 10db or 10 times the power, so you can see how power/current can quickly ramp up when sensitivity is considerably lower. SPL also drops off 6db (x4 power) every time you double distance (remember speakers are rated at 1m), so by the time you're 10 feet away, you're requiring x16 as much power to get that same SPL level from the speaker.

 

[John Lohmann]

Thanks for your input, Nick.

 

[highfigh]

Who cares at this point what the meaning is behind this guy's moniker? The underlying query was about if the things being said about ohms and sensitivity were true or not, and it seems that's been answered, essentially by way of a "it depends" conclusion (taking the sensitivity element out of the equation).

Here's the thing, in a proverbial nutshell:

Because you so often read about how a speaker ohm selection in a piece of electronics should always be set to 8, regardless of scenario (otherwise, the story goes, you're severely limiting power of the amplification device), I was wondering if what I was being told regarding that was accurate.

Also, it didn't seem to make sense to me what was being said regarding lower sensitivity speakers -- I was always told these are harder to drive than higher sensitivity variants.

Lower sensitivity speakers can be rated at the same impedance as higher sensitivity varieties- sensitivity & impedance are determined by the voice coil's wire gauge, magnetic strength, distance from the coil to the magnet, diameter, number of layers....lots of variables. As long as the impedance doesn't dip too far and the voice coil's inductance isn't too high, it won't be difficult to drive. 4 Ohm speakers are harder to drive because the Current is higher and that creates more heat in the output devices, as well as taxing the power supply more than an 8 Ohm speaker.

Definitions and descriptions matter- ask some people a question and the answer is clear & concise, ask others and it's overly-technical and harder to understand- the problem is that when people are put in support positions, the ones hiring them don't ask the right questions and don't necessarily know what to ask in order to find the best communicators.

I would like to go back in time to the point where the idiot from Associated Press was about to release the personal info for the technical trainer from a major electronics manufacturer, grab them by the neck and say "Don't even think about it!".

 

[highfigh]

That's not how he explained it to me -- he DEFINITELY used the term "engineer" -- but you could be right.

And he may be an engineer, but if you read my previous post, not everyone is a great communicator and not everyone understands what they hear in the same way. If you can call back and find the same person, maybe you can ask them to explain why it's harder to drive, assuming the impedance of both is basically the same. Or, you may speak with a different person who explains it differently.

 

[highfigh]

I'm not an engineer so someone can feel free to correct me if I misspeak here.

As Peng said, Impedance is basically resistance at a given frequency. So less resistance can be interpreted as easier flow of electrons. So correct in that interpretation I guess.

When dealing with speakers, amps and volume though, sensitivity is a rating of SPL (loudness) at 1W and 1 meter away. As you increase loudness, you require more power. Power is I^2 * R (current squared times resistance). So current might flow easier through that lower impedance, but more of it is required to achieve the same power (and thus SPL/loudness) at the lower resistance.

If you're trying to put out 100W into 8 Ohms, you require ~3.5A of current from the amplifier.
If you're trying to put out 100W into 4 Ohms, you require ~5A of current from the amplifier.

Most people will interpret that behavior as being "harder" on the amplifier. Which is where the disconnect from the Denon rep's statement is.

As far as sensitivity goes, it takes double the power to increase output (SPL) by 3db. So in order to get an 83db sensitivity speaker to be the same perceived volume as an 86db speaker, you automatically need twice as much power. Perceived "twice as loud" is an increase of 10db or 10 times the power, so you can see how power/current can quickly ramp up when sensitivity is considerably lower. SPL also drops off 6db (x4 power) every time you double distance (remember speakers are rated at 1m), so by the time you're 10 feet away, you're requiring x16 as much power to get that same SPL level from the speaker.

One thing that can create problems in understanding this whole issue is that the commonly used test voltage is 2.83V, which calculates to 1 Watt ONLY at 8 Ohms. Using that voltage with a 4 Ohm speaker calculates to 2 Watts and amplifier output is in Watts, not Current.

A 4 Ohm speaker with 84dB@1 meter sensitivity using 2.83V input is a poor choice when someone wants to peel the paint in a large room when 100W results in ~104dB @ 1 meter.

 

[PENG]

amplifier output is in Watts, not Current.

Obviously that is the case based on the conventional ways of how manufacturers specified amplifier output from day 1 (I assume). Unfortunately, it would have been better if they use rated voltage and current with specified load conditions (among other metrics, such as 20-20kHz, THD+N<0.1% etc.etc.) instead of watts. Amplifiers are used with loudspeakers, not resistors.

 

[John Lohmann]

And he may be an engineer, but if you read my previous post, not everyone is a great communicator and not everyone understands what they hear in the same way. If you can call back and find the same person, maybe you can ask them to explain why it's harder to drive, assuming the impedance of both is basically the same. Or, you may speak with a different person who explains it differently.

I was merely explaining why I was of the personal opinion that this was someone outside of a general support center I was speaking with, as the question was asked "what makes [you] think....."?

 

[highfigh]

Obviously that is the case based on the conventional ways of how manufacturers specified amplifier output from day 1 (I assume). Unfortunately, it would have been better if they use rated voltage and current with specified load conditions (among other metrics, such as 20-20kHz, THD+N<0.1% etc.etc.) instead of watts. Amplifiers are used with loudspeakers, not resistors.

Right, but consumers have limited understanding of the technical aspects. I have posted about the 'specs race' in the time around 1980, where the audio magazines published reports that included specs, but didn't explain them, so people would come into the store carrying their copies of Audio, Stereo Review, Consumer Reports, etc and with a look of price, ask about something that wasn't even correct- 'How many Amps does this put out?" was a very common one, 'What's the Slew Rate?" was another.

 

[PENG]

Right, but consumers have limited understanding of the technical aspects. I have posted about the 'specs race' in the time around 1980, where the audio magazines published reports that included specs, but didn't explain them, so people would come into the store carrying their copies of Audio, Stereo Review, Consumer Reports, etc and with a look of price, ask about something that wasn't even correct- 'How many Amps does this put out?" was a very common one, 'What's the Slew Rate?" was another.

Very true, but there is not much we can do about that though. Perhaps, If I were a sales rep, I might just give them answers that don't require any more than very basic engineering, physics and/or math knowledge except if they questions further and becoming obvious that they do know the basic theories then I would try to go further. Otherwise my answers would just be based on manufacturer specs, but for more technical types such as slew rate, I would just give them the kind of rule of thumb answers such as Audioholics (by Gene in this case). If the questioner seems to know his stuff then I might go as detail as showing them how to calculate the approx number required for their use case. I have yet to meet a sales rep, including high end stores who sells the likes of McIntosh, Krell, Passlab, let alone Bouder and D-Agostino's lol... That's probably expected, it is unlikely that a electronics designer, engineer etc., would work as sales rep in an AV dealer. Some would do it for specific reasons, such as a retiree getting bored, or some enthusiasts want to do it part-time for fun.

 

[highfigh]

Very true, but there is not much we can do about that though. Perhaps, If I were a sales rep, I might just give them answers that don't require any more than very basic engineering, physics and/or math knowledge except if they questions further and becoming obvious that they do know the basic theories then I would try to go further. Otherwise my answers would just be based on manufacturer specs, but for more technical types such as slew rate, I would just give them the kind of rule of thumb answers such as Audioholics (by Gene in this case). If the questioner seems to know his stuff then I might go as detail as showing them how to calculate the approx number required for their use case. I have yet to meet a sales rep, including high end stores who sells the likes of McIntosh, Krell, Passlab, let alone Bouder and D-Agostino's lol... That's probably expected, it is unlikely that a electronics designer, engineer etc., would work as sales rep in an AV dealer. Some would do it for specific reasons, such as a retiree getting bored, or some enthusiasts want to do it part-time for fun.

There's a lot that can be done about it, but it would require a time machine, to get people to learn Science & Math- I helped take a yacht to the marina so it could be hauled out & Winterized on Thursday evening and in the course of the trip, some of us were talking about 20-somethings not being able to count change at a register- I dug deeper into this and gave a few examples of info people should know, but don't. We have discussed the Metric System and American's resistance to it on AH, none of the others know or use it. We talked about Math that's at the level of Algebra or above, only one did well in that. They don't seem interested in learning, even though the son of the boat owners has always been a Math whiz and has advanced degrees in Applied Mathematics. They almost seemed to be saying "It's too late for us, save yourselves".

Sales reps are required to sell, not provide technical info. When I started selling audio in '78, our reps were often knowledgeable, some not so much. Many were great WRT the business aspects of running an audio store and we benefited from them greatly but the salespeople at the store weren't the ones who knew the most about this stuff, they were just able to close more sales. Sometimes, they saw more returns, but their totals were higher, so they made more money for the store and that's what the owner wanted.

Big box stores have very few knowledgeable sales people in this city- I don't want to shop them because people mainly buy on price but the last time I was in the same place as a Magnolia 'consultant', I was told that the Def Tech 8090 speakers don't have a line input for the woofers. That was absolutely incorrect and it was just after she asked why I had installed coax to the speaker locations.

You really think a store owner wants to hire someone who's retired & bored or an enthusiast who wants to do it for fun? That's the last thing they want- people who have seen decades of BS or someone who wants to make friends and talk all day. A B&M store is competing with the internet, or were you referring to online companies like Crutchfield, etc?

I would hate to be an uninformed consumer- the support people are leading them into the weeds without leaving clues for getting out.

 

[PENG]

You really think a store owner wants to hire someone who's retired & bored or an enthusiast who wants to do it for fun? That's the last thing they want- people who have seen decades of BS or someone who wants to make friends and talk all day. A B&M store is competing with the internet, or were you referring to online companies like Crutchfield, etc?

I would hate to be an uninformed consumer- the support people are leading them into the weeds without leaving clues for getting out.

Right, no they won't hire those people, that's why I said what I said.. No technical sales people, just skillful, knowledgeable enough will do, you may be one of the most technically knowledgeable one in the business so may be endangered lol..

 

[highfigh]

Right, no they won't hire those people, that's why I said what I said.. No technical sales people, just skillful, knowledgeable enough will do, you may be one of the most technically knowledgeable one in the business so may be endangered lol..

People outside of the manufacturers need to be up on the technical stuff because they sure aren't providing it and the time/effort needed to find the info and gain the experience in operating the equipment takes a lot of time, so it has a substantial cost to the installer/dealer. Then, people still want to slog through setup after buying from online dealers, continuing to believe B&M dealers charge too much.

To be honest, that belief is offensive and I'm not easily offended. They want to pinch their pennies AND have the knowledge/info handed to them.

To be honest, because of the BS that comes with HDMI, incomplete info, unnecessary complexity and people wanting their equipment to do things they don't understand in rooms that aren't conducive to elaborate surround speaker installations, I would much rather work with purely audio systems. If someone wants to hear the sound from their video equipment, fine but the manufacturers need to stop dangling shiny objects in front of people and shoving BS down our throats.

How many use the 3d capability in their TVs? Not many. Do they still build it in? Yup.

 

[head_unit]

low impedance makes a speaker MORE DIFFICULT to drive, not easier,

It's a matter of semantics. At a given volume setting, lower impedance draws more current from the amp. Hence the amp can push a given amount of power more easily. But on the other hand the amp will run out of current and clip sooner = harder to drive. This relates back to those "4 ohm" switches which my understanding is cut the power output to pass some European heat test or such.

The "8 ohm" setting should be fine as long as you're not clipping. What happens is people can't play loud enough so they keep turning the volume up into distortion. Their "130 watt" receiver square waves the bass to 200 watts, but some treble note that should be 1 watt normally suddenly becomes 20 watts and the tweeter dies.

 

[Kaskade89052]

It's a matter of semantics. At a given volume setting, lower impedance draws more current from the amp. Hence the amp can push a given amount of power more easily. But on the other hand the amp will run out of current and clip sooner = harder to drive. This relates back to those "4 ohm" switches which my understanding is cut the power output to pass some European heat test or such.

The "8 ohm" setting should be fine as long as you're not clipping. What happens is people can't play loud enough so they keep turning the volume up into distortion. Their "130 watt" receiver square waves the bass to 200 watts, but some treble note that should be 1 watt normally suddenly becomes 20 watts and the tweeter dies.

Thanks for the thoughts.