Power Hungry Speakers Question

[62caddy]

The way I look at it... Let's say your speakers are around the 90db efficiency range. At 8 watts, you'd be at 99db. Subtract 12db for another 2 meters of listening distance. That leaves you at roughly 87db, which is a fairly comfortable listening level.

Don't forget to add 3 dB for a pair of speakers therefore 8 wpc (16 watts total) is a theoretical 102 dB, not 99. Are you certain about -12 dB @ 2 meters? As sensitivity is already quoted @ 1m, -12dB seems a bit high an SPL loss for one additional meter.

 

[Rick Vestal]

Don't forget to add 3 dB for a pair of speakers therefore 8 wpc (16 watts total) is a theoretical 102 dB, not 99. Are you certain about -12 dB @ 2 meters? As sensitivity is already quoted @ 1m, -12dB seems a bit high an SPL loss for one additional meter.

I was roughly guessing at the distance most people sit away from their systems. so for doubling 1 meter, -6db, doubling that again to 4 meters, another -6. I suppose in most cases it less than 4 meters.

 

[hopeless]

So which is more "power hungry" 84dB - 8 ohm speakers or 96dB - 4ohm speakers?

Kind of a loaded question. The real question would be how reactive the speaker load is. The other question is how conservative is the rating since an 8 ohm speaker is only 8 ohms in passing. Same with a 4. Speaker ratings are just not real useful. Then again, neither are amplifier specs. Then we have to change our thinking when you hook up a speaker to the amplifier. Hence the mystery of audio.

 

[opnly bafld]

Kind of a loaded question. The real question would be how reactive the speaker load is. The other question is how conservative is the rating since an 8 ohm speaker is only 8 ohms in passing. Same with a 4. Speaker ratings are just not real useful. Then again, neither are amplifier specs. Then we have to change our thinking when you hook up a speaker to the amplifier. Hence the mystery of audio.

Well at least your user name is accurate.

Did you read the reason I made the post?

 

[GordonW]

Well at least your user name is accurate.

Did you read the reason I made the post?

I think he does, honestly.

There are quite a few cases, where speakers are rated at "96dB" or some other very high nominal sensitivity- only for one to discover, that to do that- the manufacturer has ACTUALLY created a system where the impedance dips down to 1-2 ohms at places- in order to make the speaker SEEM like it's more sensitive than it really is.

IF- and ONLY IF- the speaker is ACTUALLY 96dB at 1 watt, one meter- and NOT the more common "voltage equivalent" to 1 watt (2.83v)- will it actually be guaranteed to be that efficient with power. A speaker that's rated at 96dB "sensitivity" at 2.83V, but is 2 ohms in reality, will draw FOUR TIMES the power that one that is actually 8 ohms, at the same voltage gain from the amp.

So, to take the original question to its extreme- say, the 96dB sensitivity speaker is actually, effectively, 1 ohm. Say the 84dB sensitivity speaker is actually 16 ohms. At 96dB output- the former will be drawing 8 watts. At 96dB output, the 84 dB sensitivity, 16 ohm speaker will also be drawing 8 watts. But, the 84dB speaker, with its 16 ohm load- will be much easier for the amp to drive. Yes, an absolutely outlandish example- but entirely possible, given the way many specifications are vaguely worded.

To mis-quote Mark Twain- lies, damn lies, and vague specifications...

Regards,
Gordon

 

[opnly bafld]

I'm glad that at least a few understood the reason for my post, it would be expecting too much to think everyone would get it.

 

[rothwellaudio]

Don't forget to add 3 dB for a pair of speakers therefore 8 wpc (16 watts total) is a theoretical 102 dB, not 99. Are you certain about -12 dB @ 2 meters? As sensitivity is already quoted @ 1m, -12dB seems a bit high an SPL loss for one additional meter.

I was roughly guessing at the distance most people sit away from their systems. so for doubling 1 meter, -6db, doubling that again to 4 meters, another -6. I suppose in most cases it less than 4 meters.

Those calculations are only applicable to speakers in free space. In a room the SPL drop-off with distance isn't that dramatic.

 

[titanstats]

Never met a speaker yet that a quality 100w amplifier couldn't drive to way louder levels than I need.

Really made a difference with some of the speakers I had. KEF 105 were very hungry, 125WPC wasn't nearly enough for them, had my powerguard coming on at quite reasonable listening levels. Doubling the available power made them a much better speaker, there's plenty of other speakers the same. My Altecs are happy with much less power.

AR-9 have impedance which drops to as low as 2.7 ohms with frequency. Many amplifiers can't drive a 2.7 ohm load with the current demanded of it, and the power demands of AR-9.

Another of the speakers I was thinking directly about. It was an era of amplifier and receiver power wars, many popular speaker designs of the day reflected this.

 

[Akustic]

Kind of a loaded question. The real question would be how reactive the speaker load is. The other question is how conservative is the rating since an 8 ohm speaker is only 8 ohms in passing. Same with a 4. Speaker ratings are just not real useful. Then again, neither are amplifier specs. Then we have to change our thinking when you hook up a speaker to the amplifier. Hence the mystery of audio.

And nominal (not real but we'll presume) impedance ratings are another fly in this ointment of calculated SPL's, efficiencies and required power to achieve a given SPL...
The reality is that impedance is endlessly variable with the frequency being reproduced as the music plays ..

 

[hopeless]

And nominal (not real but we'll presume) impedance ratings are another fly in this ointment of calculated SPL's, efficiencies and required power to achieve a given SPL...
The reality is that impedance is endlessly variable with the frequency being reproduced as the music plays ..

And herein lies the problem. This is before we get to phase angles and back EMF. Somehow "4" just doesn't do much to communicate what the speaker wants to do to your amplifier.

 

[rothwellaudio]

And herein lies the problem. This is before we get to phase angles and back EMF. Somehow "4" just doesn't do much to communicate what the speaker wants to do to your amplifier.

True, but impedance curves for speakers are often published, if not by the manufacturer then by magazine reviews.

 

[hopeless]

I think he does, honestly.

There are quite a few cases, where speakers are rated at "96dB" or some other very high nominal sensitivity- only for one to discover, that to do that- the manufacturer has ACTUALLY created a system where the impedance dips down to 1-2 ohms at places- in order to make the speaker SEEM like it's more sensitive than it really is.

IF- and ONLY IF- the speaker is ACTUALLY 96dB at 1 watt, one meter- and NOT the more common "voltage equivalent" to 1 watt (2.83v)- will it actually be guaranteed to be that efficient with power. A speaker that's rated at 96dB "sensitivity" at 2.83V, but is 2 ohms in reality, will draw FOUR TIMES the power that one that is actually 8 ohms, at the same voltage gain from the amp.

So, to take the original question to its extreme- say, the 96dB sensitivity speaker is actually, effectively, 1 ohm. Say the 84dB sensitivity speaker is actually 16 ohms. At 96dB output- the former will be drawing 8 watts. At 96dB output, the 84 dB sensitivity, 16 ohm speaker will also be drawing 8 watts. But, the 84dB speaker, with its 16 ohm load- will be much easier for the amp to drive. Yes, an absolutely outlandish example- but entirely possible, given the way many specifications are vaguely worded.

To mis-quote Mark Twain- lies, damn lies, and vague specifications...

Regards,
Gordon

Even then, it's a 1k signal. It's not full frequency. I'm just not too keen on the compromises needed to make high sensitivity drivers anyway. Short coil/short gap drivers have issues, as do huge enclosures. But, others don't mind.

 

[hopeless]

True, but impedance curves for speakers are often published, if not by the manufacturer then by magazine reviews.

Then you just need an audience able to interpret them, or to expend the effort to find them. Still, much of the story is left untold.

 

[sae-7125]

speaker efficiency goes up and hearing efficiency goes down, wonder if its the high dynamics over a lifetime. tinnitus is no picnic either.


.


fun with voltage and deciBel
https://audiojudgement.com/how-to-calculate-decibels/

 

[Sgt Shultz]

@hopeless it's really hard to say if "you'll" hear the difference on your system

It's more like the topology of the amp that's going to make a bigger difference in SQ.

My AR's are rated 3.2ohms, most integrated amps and receivers shouldn't apply, along with many amps. I prefer the AR's with one of my Belles amps rated 100w at 8ohms with enough current to pull a freight train, I hear 185w at 4ohms and no reason to doubt it.

But I worried it might be straining the Belles so the AR's are now connected to a Soundcraftsmen MA5002 rated 360w at 4ohm and 2ohm stable.


Now all is relevant, what exactly is soft? What I consider soft you might consider loud. I always worried about cranking them with the Belles, but now I don't have to.

I do prefer the sonic character of the Belles, with my Infinitys also so there's that, but the Soundcraftsmen sure does sound effortless, reminds me of my old McIntosh MC-2002 in that respect.

The Belles Model I, kinda rare but a real bargain if found, I now have 3

It's simple design let's the music just flow, David Belles is a highly regarded designer.






Some objects added for size reference

 

[BMWCCA]

Currently listening to a pair of DCM Time Frame 600 (92dB sensitivity 6-ohm) at low level powered by a Crown Studio Reference-II (350WPC at 8-ohms). They sound better than they have with every other amp I've used with them. But then the Studio Reference seem to do that with every speaker I own! And I have plenty of other amps. And speakers!

 

[Akustic]

As I said in my initial response, sound quality will improve with more power if the signal is being clipped. Sounds like you agree with me

If it is not, additional power is irrelevant by definition, because it is unused.

Damping is not related to power capability.

Regarding your comment about low power aficionados; first, I am not one. This is because my speakers are of low sensitivity. Second, it is patently ridiculous to suggest that those who use lower powered amps don't appreciate dynamics, since they can achieve exactly the same "dynamics" as those using higher-powered amps, assuming appropriately matched speakers.

Patently ridiculous is a pretty strong statement .. especially in advocacy of lower power achieving exactly what higher power does ..
Why did we ever begin using higher power devices then ??
To a degree, you're beggaring the evolution of audio and the development of higher powered amps ..

I would guess that we're using the word "dynamics" very differently ...
It's a pretty subjective subject with, at least for me, a lack of word to describe subtle phenomenon in the music ..

If I said that it's sharper, the notes have improved definition, and the overtones and reverbations are more distinct, I would be closer to what I'm calling "dynamics".
Sharper, clearer, more realistic ..
There are a lot of ways to spin these words..
I hear it ..especially in the bass.. the slap of the pedal on the kickdrum is more distinct .. sharper and more clearly defined .. the drum resonates..

Like you, I listen both ways ..
I have pair of 1958 ElectroVoice 12TRX Sentry's with limited throw 12"coaxial driver's .. certainly made for the EL34 tube amp that's driving them.
Wonderful sounding, yes, especially that midrange, but their bass abilities are definitely limited ..
With two identical DAC's, it's certainly easy enough to directly compare them to the 4-way JBL towers that are bi-amped with two 200wpc amps
at the other end of the room ..

Different Strokes ..

 

[Akustic]

For reasons to be speculated upon ..

For decades, my experience has been that there is a lack of bass definition when there is a lack of available current ..
When there are no further improvements in bass definition, I have enough power ..

And it's certainly discernible at lower listening levels ..
Best example would be the ability to clearly define those bass notes as being either kick drum or bass guitar, or a combination of both .. lesser amps smear them together.

 

[rothwellaudio]

Why did we ever begin using higher power devices then ??
To a degree, you're beggaring the evolution of audio and the development of higher powered amps ..

Higher power became available at a lower cost when transistor amps came along, and then when more robust transistors became cheap. A 25 watt amp used to be considered adequate, but any manufacturer who could offer 50 watts would have an advantage when trying to appeal to the people who believe "more power is better, right?". And that means the majority of potential customers.
Then 100 watt amps became commonplace. The power wars continue.

Yet there are plenty of audiophiles buying new (or old) amps which have miniscule power outputs compared to what's available much cheaper, and I'm sure it isn't an act of complete stupidity on their part. I presume those lower powered amps are doing something which they can't get from something else. Or do they just look pretty?

 

[62caddy]

I have pair of 1958 ElectroVoice 12TRX Sentry's with limited throw 12"coaxial driver's .. certainly made for the EL34 tube amp that's driving them.
Wonderful sounding, yes, especially that midrange, but their bass abilities are definitely limited ..
With two identical DAC's, it's certainly easy enough to directly compare them to the 4-way JBL towers that are bi-amped with two 200wpc amps
at the other end of the room.

Whoa there. The limited bass of the high sensitivity speakers would still exist even if the higher power amplifier was used with them. You're conflating variables when two completely different speakers are used to compare the performance of two different amplifiers.