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75.23.6.3
If a speaker is 78-80dB sensitive, does it mean lower resolution even if adequately powered?
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The best speakers I've heard have all been mid sensitive with killer resolution.
It's a small factor. Resolution comes from following the signal which needs stopping and starting accurately. Both are problems but I've always felt stopping a resonant device like a speaker is more difficult. Efficient speakers tend to be lighter which helps changes in motion. But other factors like crossover/driver transfer functions are probably more important based on examples I've heard.
In a word - no.
Sensitivity has a very precise definition and is frequently (as some in this thread have clearly done) confused with efficiency. THEY ARE NOT EQUIVALENT.
REPEAT AFTER ME:
SPEAKER EFFICIENCY IS NOT EQUAL TO SPEAKER SENSITIVITY.
Loudspeaker sensitivity is defined as the number of decibels of sound emitted per applied voltage - usually 2.83V which translates to about 1 watt of electrical energy when applied to an 8 ohm nominally rated speaker. Some speakers will produce 85 db (modest sensitivity) and others will produce well over 90 db (high sensitivity). This doesn't mean however that the higher sensitivity speaker is necessarily more efficient. The higher sensitivity speaker could develop a higher output because it draws more current into a lower nominal impedance - say 4 ohms. What is key are the number of watts consumed to produce a given decibel output - and that is how acoustic efficiency is defined. Some 92 db sensitive speakers might need only a watt to achieve the specified sound output level (pretty efficient) while others might need several watts (not so much). High efficiency speakers will invariably deliver more life like dynamics. High sensitivity speakers may or may not - depending on how many watts they consume in the process. On the flip side, you can have a 12 or 16 ohm nominal impedance speaker that doesn't generate a lot of sound for a 2.83 V input. But the high impedance alone doesn't make it less efficient and thus it could still possess excellent dynamic qualities. The general trend is that high sensitivity speakers are often higher than average efficiency but this is not always the case and cannot be assumed as the rule. Tom touched on several issues that also need to be considered in the grand scheme of things.
"On the flip side, you can have a 12 or 16 ohm nominal impedance speaker that doesn't generate a lot of sound for a 2.83 V input. But the high impedance alone doesn't make it less efficient and thus it could still possess excellent dynamic qualities."
Perhaps I am misreading or misunderstanding but doesn't the "high impedence" make a speaker MORE efficient? For example, I would think a "nominal" 8 ohm speaker that does not go below say 7 ohms is more efficient than a nominal 4 ohm speaker that goes to 3 ohms or so since the latter "consumes" or requires more watts than its higher impedence counterpart for a given level of sound("What is key are the number of watts consumed to produce a given decibel output - and that is how acoustic efficiency is defined")?
The phrase you mentioned "for a given level of sound" is the sticking point. Yes, if you have a high nominal impedance speaker putting out the same level of sound as a lower impedance speaker when both are driven by the same force (2.83V for example) - then clearly, the higher nominal impedance speaker is more efficient. But they need to output the same level of sound. Again, we're back to the definitions:
Efficiency - ratio of acoustic energy output to electrical energy consumed
(decibels to watts)
Sensitivity - ratio of acoustic energy output to electrical force applied
(decibels to volts)
After all, this is not meant to be the engineering board just general, read that as simplified, consumer questions. As we all know, loudspeakers in general are horribly inefficient. They convert 1% or less input power into acoustic power, the rest 99% being converted into waste heat. It was not necessary to get into details of energy conversion efficiency.
Most here assumed what was being asked, in very general terms, was if one speaker had an advertised sensitivity rating of say 93dB would it therefore be more dynamic than a competing speaker that had an advertized sensitivity rating of say 81dB. Furthermore, the published sensitivity ratings of speakers are assumed to be the common usage of one watt (2.83 volts rms into 8 ohms) at 1,000 Hz at one meter unless otherwise specified such as for 4 ohm nominal speakers.
The diatribe about sensitivity vs. efficiency was not overly pedantic in the least because it directly addresses the OP's question and the misconceptions inherent to that often asked question. Once again, sensitivity is a characteristic or specification that stipulates decibel output for a commonly referenced input voltage. It is not a decibel per watt rating as you seem intent on suggesting above. Voltage (applied force) and the resulting acoustic output is sensitivity. Wattage consumed vs acoustic output is efficiency. They are not the same and because a lot of people treat them as equivalent, they end up asking questions like the OP's original question. Perhaps there wouldn't be such a need for pedantic responses if this misunderstanding were not so persistent or widespread. Everyone from Stereophile's Atkinson to people like me have attempted to improve understanding and awareness on this issue so that people would not read too much into a loudspeaker's sensitivity rating. It is an important rating that tells you how loud a speaker will get for a specific gain setting but it doesn't accurately convey the speaker's ability to reproduce dynamic contrasts adequately. The speaker's efficiency rating is a better indicator of that performance characteristic because the ability to accurately render dynamic contrasts is ultimately reflected in the ratio of the incremental changes in applied signal versus the mean signal strength level. Loudspeakers, whether they possesss a high or low nominal impedance will be better able to convey dynamic contrasts if energy losses are reduced (higher efficiency) since energy losses in most energy conversion devices are not linear phenomena. So if energy losses are more dominant, the non linearity in dynamic response associated with energy losses will also be more dominant.
The concepts are somewhat subtle. So we have to work doubly hard to improve understanding so that people don't wind up making wrong assumptions about loudspeakers - effectively removing some from consideration and including others based on incorrect assumptions. This may be a pedantic exercise to you but to people in the business of making and selling speakers, it really matters whether or not prospective buyers have an adequate understanding.
What a strange question!
Not really. I think he just doesn't understand the meaning of these terms.Hope he learns something from the answers he is getting. That should be one function of the asylum. To educate
Alan
A case of the blind leading the blind I fear, or is that the deaf leading the deaf?
Finding a pair of F-81s in good nick probably isn't easy these days but the very low sensitivity (70-some dB?) F-81s walk all over 105 dB K-horns when it comes to resolution. The K-horns will certainly play much louder and do macro dynamics better but with far more coloration and less resolution than the Stax speakers.
Its not nearly as inefficient as the spec would lead you to believe and that is because the sensitivity is rated as 8 ohm equivalent and as such it rates very low. However, the F-81 is NOT an 8 ohm speaker. It actually goes up to a few hundred ohms at the peak (60 ohms in the bass). This means that it plays wonderfully with a tube amp and not very good at all with a typical SS amp. We got the best sound from a 100 watt tube amp and a 30 watt SET.
The resolution is simply the best I have heard from any speaker and it is not necessary to play loud to get the full meaning of the music. Pity they are no longer made...I would dearly love to get a pair of F83s someday.
Des
all were down in the 70dB range for one watt. The Stax was 73dB for one watt in and the original Large Apogee was around 76 to 78dB efficiency. The AHL was down to below 71dB. It actually clipped 500 watt monoblocks during a demo without even being loud.
As a side note. Only two companies currently manufacture plasma tweeters, Lansche and Acapella Audio Arts.
For background, had the Stax, still have the Large Apogee and almost bought one of only four sets of AHL Tolteques that were ever imported into the USA. Unfortunately, the deal fell through due to various problems; shipping being one of them. The AHL came in eleven crates and weighed far over a ton, transportation would have run more than the agreed upon price. C'est la vie.
Would shut down the Stax DA300.
Des
It was the reactive load!
Nelson Pass was among the first to design amps specifically to drive the Dayton-Wright. Back in the 70s, he would demo his electronics using vertically stacked Daytons.
A Threshold Stasis has served me well for over three decades driving various Acoustats.
nt
D
We called em Dayton Wrongs.
Ha !!
And had an Amp that could -you had sublime presentation hard to match today.
Amps?--mine could ---bridged ER A75's
Des
Which was needed to prevent arching. However, one can still buy it at Specialty Gas suppliers.
Such as;
nt
Des
aka JWC from the early days of The Absolute Sound used Dayton-Wrights. I once assisted in the replacement of a panel which necessitated breaching the outer diaphragm for access. Once the panel was replaced and the outer diaphragm patched, he had to re-pressurize the cabinet.
SF6, like helium, is inert but heavier than air. Put some in a cup and it stays there. You can feel it by putting a finger in the cup. As a baritone for the Atlanta Symphony Chorus, he has a deep and powerful voice. He inhaled a big breath of it and started singing. It was like hearing Lurch at the Met! Very funny.
However cranky they were, it was the Dayton-Wrights that converted me to a stat enthusiast long ago.
Yes I think JWC actually liked them
I recall poking a knitting needle with non toxic Silicon blob on tip throughout the Mylar--
to seal an arcing spot.
Only delayed the inevitable though
Certainly an enigma product--merely a pothole in the my Audio roadway.
I actually bought one pair--but ending up owning 3 sets-freebies in leu of breakdowns-and tried
a stacked pair.
What the hell was I thinking!
Des
nt.
which were notorious for challenging amps.
It was the motto of Cabasse in the '70s.
Cabasse was one of the best speaker manufacturers in the world, and when I compared them to others, they were always the closest to real music (acoustic instruments), despite not being the best in terms of F-3, nor even flatness of frequency response.
They were making closed enclosure, non-horn loaded speakers with efficiency (not sensitivity) of 93 to 98 db/w!!!
Other great speakers of the period, like B&W, sounded 'dead', 'boring' in comparison.
From your description I suspect the Cabasses were dynamically linear; they changed level in a linear fashion. This is probably more important than perfectly flat response and/or loudness ability, which is what toomany people think dynamics are, in portraying a sense of being there for real.
There isn’t a yes / no answer as a number of things are involved.The sound level falls 6dB every time you double the distance to the speaker so the closer you are to the speaker, the easier it is to reach a given sound level.
With a sensitivity of 80dB (1 Watt 1 Meter) and if you sat 4 meters from the speaker, you know the level the speaker is producing will be about -12dB from a one meter distance.
If the speaker could handle say 50Watts that mathematically speaking the maximum level the speaker could produce would be (10X the log of input power) over the 1Watt sensitivity or 96.9dB spl.
At the listening position 4 meters away (not including reflected room sound) the Spl would be 84.9dBSpeakers are not dynamically linear, if you double the input power it doesn’t always get twice as loud.
At a level about 1/10 to 1/8 a drivers rated electrical power, the heating of the voice coil wire causes the drivers parameters to change and the sound level falls short relive to the linear case.
Thus, if you want linearity, you need to operate the driver well under its capacity and that is one reason pro-sound drivers are sometimes used in hifi, they are loafing along.
Now music.
Music or most music has dynamic range, it goes from soft to loud, typical FM radio rock has about a 10dB difference between the largest peaks and the average level, that means the peaks represent 10 X the average power.A good “hifi” demo track on the other hand may have 20 or 30dB or occasionally larger difference between the peak and average levels and what we hear as "loudness" is nearly the average level .
In the case above, if one played on of those good recordings with a lot of dynamic range, say 30dB, this would then mean that your average level must be -30dB down from the maximum level your speaker can produce or the peaks will not be produced. At the listening position, in the example, that average level could be no more than 54.9dB spl (would work in a very quiet space.
My taste is dynamic range and no compression. Take an SH-50 a single source full range horn that has a sensitivity of 100dB 1W 1M. That speaker can produce 100X or +20dB more sound for a given input power.
Power handling, with pink noise (worst case) at the first point where the frequency response deviates only 3dB from the 1 Watt curve due to power compression, takes over 600Watts average input power (and a 2400Watt amplifier to source the signal). If one drove it that hard at the same 4 meter distance would produce a peak level of 121.8 dB or with that hifi recording and 2400Watts peak, an average level of 91.8dBHow loud do you need it, how far away are you from the speaker what the program material is, how much power you have and system sensitivity and power handling all come into what is needed to be faithful to the signal.
Best,
Tom Danley
Danley Sound Labs
Edits: 07/21/12
Wow Danley!
Thank you
As others have ointed out it is more a question of restricted dynamics. I cant ever seeing myself with single driver speakers and horns still have too many problems for my taste to consider. I will admit that the dynamics of horns are intoxicating.
Thermal/power compression is also an issue with pro sound gear at high output, and especially pro subs driven hard outside for long periods of time at high output.
Voice coils heat up and thus resistance increases on the coil and issues with having less output and having to push amplifiers harder to achieve the same output occur. This is not limited to home audio low efficient gear in the sub 90db range.
A horn system with high efficient drivers "done right" is hard to beat
in dynamic impact.
The lesson to be learned here is keep a cool voice coil if possible.
I wouldn't say that a lower sensitivity speaker tends to be lower resolution, but there does seem to be a pretty high correlation between sensitivity and dynamics. High efficiency speakers, especially with horn loading, tend to have more sudden dynamic changes. I am not just talking about 1812 Overture dynamics. All types of music benefit from wider dynamics and you can hear this even at lower volume levels. I think that realistic dynamics may be the single biggest factor in making a hifi sound closer to real music.
Unfortunately, many high efficiency speakers suffer from other problems like horn colorations and irregular frequency response. So the trick is finding a high efficiency speaker that doesn't compromise in areas of frequency balance, coloration, coherency and resolution.
Once you hear the dynamics from a high-efficiency speaker in your own home, it is hard to go back to less dynamic speakers. At least that's been my experience.
Nice post Salectric,What NO one has brought up here, yet it is cogent, is that it is easier to build a great sounding low power amplifier, than a great sounding high power amplifier.
The more devices you parallel, to get high power, the less transparent and more mismatched the performance.
So, when you use a low sensitivity speaker with a high powered amplifier, it becomes a compromise, (assuming one knows how to make, or acquire, a great-sounding low powered amp.)
Don't get me wrong, there are a few positively great sounding high powered solid state amps, but how many of us a) know which ones they are and b) can afford to buy them??
Jeff Medwin
Edits: 07/22/12
SET amps rule IMHO
"I think that realistic dynamics may be the single biggest factor in making a hifi sound closer to real music."
No but they do have to deal with thermal compression.
but typically that's the endgame result. More power into a given motor means more distortion, more compression, more flux modulation. All of these things lead to heavy advantages in higher-efficiency speakers.
Bass is supposed to sound big. 6.5" is not a woofer size.
While greater efficiency carries with it some theoretical advantages if you are listening to wide dynamic range music at high volumes in most home listening contexts it is a minor issue. I, for one, have no desire to replicate concert hall or bar listening levels in my home, at least not on regular basis. Within their bandwidth and maximum volume limitations there are quite a number of relatively inefficient speakers that I would opt for in a heartbeat over the classic high efficiency speakers (Klipsch, Altec, JBL, Lowther, etc.) because I find them vastly less colored and far more faithful to the music. To make very broad generalization I find that good low to medium efficiency speakers at least equal and in many case exceed the resolution of the high efficiency speakers I have heard. I must confess, however, that I've listened to relatively few of the modern 95dB+ efficiency speakers but of the ones I've heard only the Avantgardes did much for me.
Edits: 07/20/12 07/21/12
Thank you badman,
Meaning the (ultra) fidelity will suffer?
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