Loudspeaker sensitivity and dynamics: are the two inexorably linked?

Hello all,  I don't dive in much these past couple of years. The old timers know that I have a speaker back ground and it is where I occasionally chime in.  So the question:  Are they inexorably Linked?  No, not inexorably at all, but they are somewhat linked. So what is Dynamic Range in speakers?  For easy terms, lets call it speed, the ability to move from very low volume to high volume and back without breaking a sweat or touching the volume!

Whether you have a 10 watt amplifier or a 1000 watt amplifier, there is no doubt that the amp will drive a 97db sensitivity speaker dramatically easier than a 83db speaker.  I have both right now.  When you have a high sensitivity speaker, an amplifer has power reserve,  it can loaf and still drive that speaker easily.  There are amplifiers that may be decent, but not enough current reserve to handle difficult loads, then when you combine that with low sensitivity , you have a combination that sucks the life out of dynamics. Remember, you have to double your power to add 3db in volume.   When you gain the factor of high sensitivity, say 10db more sensitive that same decent amplifier now never has to be pushed hard to deliver great performance, you will find pace and dynamics both improved when an amplifier is not pushed. When an amplifier is well built with a great power supply and has CURRENT to spare and is loafing to boot,  you will find dynamics galore in a high sensitivity speaker.  Mind you, you can have a high sensitivity speaker that may not be so dynamic.  Difficult impedance loads and inductance clearly matter with an amplifier producing its best dynamics. 

So in the big picture,  a highly sensitive speaker that is well designed for a smooth impedance curve and lower inductance definitely will be more dynamic with most amplifiers than with the opposite type speaker,  but that doesn't mean a low sensitivity speaker cannot be dynamic.  If you have a well designed amplifier with the proper current capability,  Lower sensitive, well designed speakers can have great speed, air and transparency, no doubt.  

@timlub --

Good post, in which you did however only touch upon the amp side of things and not the speakers, which with low efficiency in particular will potentially further complicate issues with thermal compression/modulation as heat build-up in the voice coils, even if it’s only for short periods of time as a rather "dynamic" phenomena.

I might also add that removing the passive crossover between the amp and drivers for active configuration will have the amp(s) seeing a much easier load, with the better driver control and sonic benefits this entails, while also thriving on load independency between the amp channels coupled to their respective driver segments and limited frequency spectrums. So, a combination of high efficiency, good power handling, active config. and sufficient quality power will be among the core parameters to ensure the most optimal outset for dynamic prowess, as well as other aspects in sound reproduction.

As the article supplied by poster @ditusa points to, not everyone is in the need of the same effective headroom (if there even is any to speak of) for their specific requirements and setup context, and so to their needs may be dynamically well served with smaller, low efficiency speakers. That’s however also a clear indication of what's relative to the individual benchmark one sets about to work from, and the importance that is assigned to this specific area.

Tom Danley on headroom and power compression (excerpt):

Well before a speaker burns out, it is severely compromised in it’s performance.

With the heating of the voice coil, one finds the SPL decreases relative to the expected level with increasing power, also the systems tuning / frequency response changes at the same time, for the same reason.

For modern drivers, this power compression begins about 1/8 of the drivers rated power, if rated using the AES procedure.

Honestly there is so much BS regarding specs and such in commercial sound that to add a sense of realism or something to that mess, we have a 3rd party laboratory specify usable rated power. Hifi, don’t get me started.

https://www.avsforum.com/threads/danley-dts-10-super-spud-diy-kit.1189404/post-17409024

I want reflect on this aspect:

Using high sensitivity speakers requires a lot of attention to noise- grounding anomalies, other stuff that you would not necessarily hear through a less efficient system. 

If we consider that we have that sensitive speaker so that we are able to hear the noise floor of the system even if all is optimal and optimized.

 

Now considering also that that system is a constant and NOTHING else is changed except the speakers. Everything is the same.

 

With the sensitive speaker we have "found" and have verified that we can hear right down to the noise floor of the system. (Yeh it don't need to be enjoying at the sweet spot and nearly inaudible.

 

Now that would mean that when the softest and the most faint sound that is just breaking and is near the noise floor we will and we can hear it! We have just the whole system setup for being able to do that.

 

On the other hand if we have the exact same system and just swap out the speaker to a low sensitivity that is dead silent and no noise floor is nowhere to be found.

 

The question is where is the noise floor if you can't hear it. Are we 3 dB above the noise floor or 10 dB.. nobody really knows exactly.. but let us call it X dB.

But now there is a GAP of loudness (dB) the difference from the noise floor and up to the lowest sound we are able to hear at the sweet spot.

 

That GAP that is X dB of loudness range that the inefficient speaker has "wasted away" will give the inefficient speaker in total a lower dynamic range.

 

And if you have that sensitive speakers that you can hear the rest of the system noise floor. Then you also have a tool that you can find and swap out the component that generate most of the noise. And in that way lower the noise floor even lower so that you get even more dynamic range! 

 

But all opportunity to that optimizations is not there with the low efficiency speaker when it MASKS away the whole dB range and you can put whatever components in your system and even if they're better and have a lower noise floor and do a better job to play the softest sounds. 

Then you will not reap the benefits of that positive contribution in this area and those efforts of the component design to make it better is wasted.

 

Just my 2 Satoshi.

@phusis     I was really trying to deal with the idea of dynamics only. I did bring up efficiency a few efficiency issues, but tried to keep it in an understandable format.  To those that don't have a better idea of sensitivity vs efficiency.  The short answer:

Sensitivity measures the volume out vs the power in.  Example 90db output with 2.83v input or 90db output with 1watt of input @ 8 ohms. 

Efficiency measures the amount of output vs the amount of input in power or how much power is lost due to heat dissipation.  Example would be 100% of power in, 90% of power out, 10% loss.  

I tried to express in simple terms what for most is the culprit when it comes to dynamics and transparency.  We can discuss crossovers or thermal compression in another thread

bobbydd

You hit the nail on the head....High sensitively speakers typically do not have large and music sucking  crossovers. Crossovers are detractive, meaning they do not add music, rather just the opposite. I would caution you that when you have high sensitivity speakers it is best to get a smooth tube amplifier ie. 300B and your micro dynamics will shine. 

Jim