Bass Vs speaker efficiency

@phusis +1

Is this what you are trying to figure out?  Paul has a whole series of these, best explanations I’ve come across. 

https://m.youtube.com/watch?v=OYZMdkhC22c

@atmasphere --

... I've just not heard 'tight bass' in real life, only in stereos.

I agree. Maybe it's at least partially grounded in the fact that a more natural, fuller bass isn't readily achievable with typical, anemic subs/bass capacity and less-than-smooth coverage; when pressed to do so with added gain and higher Q the bass will sound forced, boomy and intrusive. Conversely 'tight' bass seems very often to be a compensating act for bad/unnatural bass, and thus ends up becoming a new problem as an overdamped ditto - albeit to some a lesser problem, but still not optimal. My previous SVS SB16-Ultra sub was dialed in 5dB's less hot when listening to music compared to their gain setting with movies, while my current much more powerful pair of subs use the same gain in either scenario. There's also the importance of having a live reference and knowing what bass sounds like in real (acoustic) life in the first place, and not least seeking out to emulate its imprinting via the home stereo. 

Drivers with low efficiency are a lot easier to make since they need less precision in the voice coil gap. So its easier to make money and solid state power is inexpensive, so this works for many manufacturers.

Take your lower sensitivity drivers from the likes of Audio Technology (Danish brand, also called Flex Units), Scanspeak, Accuton, ATC and others, and you'll find the price per cone diameter to likely well exceed higher sensitivity, typical pro alternatives. Boutique, field coil- or Alnico magnet-equipped high sensitivity drivers like Vitavox, Cogent, RCA (vintage) and TAD cost a small fortune, but they're far from representative and not necessary to gain most of the advantages here. 

Size on the other hand is a hindrance, as is the overall narrative/prejudice and typically different presentation that follows this segment of more efficient speakers. I certainly agree that the widespread popularity of smaller, direct radiating acoustic suspension/ported speakers and SS amps was and is still is about convenience and cost, but nowadays if people really want a big, all-out approach and efficient speaker they can have it at a cost not blowing past lower sensitivity high-end speakers - your own, beautifully hardwood handmade and drivers-costing-a-gazillion T3-3's being an example. 

The only problem is that low efficiency speakers are inherently less dynamic, owing to a thing called 'thermal compression'. This is the quality of the voice coil to heat up in an instantaneous fashion, preventing the amplifier from making as much power since its impedance of the voice coil goes up with the heat.

Agree, but even before we get to thermal compression higher efficiency speakers have something different to offer due to their sheer size and design principle, with dynamics certainly being one of their traits in addition to ease and other. Passive cross-overs are another bottleneck, if you ask me, and only exacerbates the problems inherent to lower sensitivity speakers in particular.   

Is it possible that their reasoning has less to do with cost (they can always pass on the cost) or precision (I’m sure they have the manufacturing prowess to address precision), but maybe they feel that less efficient speakers bring something to the table that higher efficiency ones cannot? In other words, it could very well be a conscious design decision driven by the type of sound they’re aiming for and not necessarily cost.

  It could be- I have no idea what that 'sound' might be. IMO the only 'sound' to be looking for is one that is neutral so music can sound real. IMO that is the goal and the efficiency would have nothing to do with it. Based on that the thermal compression exhibited so often would seem to take away from that.

@atmasphere -- sorry I don’t know how I missed your response earlier. I really appreciate the explanation. It seems to me that you’re basically implying that the primary reasons the manufacturers continue to build low efficiency speakers has to do with cost and the fact that they don’t need much precision to build, which again translates into lower manufacturing costs.

I have been reading your posts and have a lot of respect for your experience and knowledge, so I hope this doesn’t come off as confrontational because that’s certainly not my intent. Having said that, I don’t know if your explanation makes complete sense to me. There are a number of highly respected manufacturers like Harbeth or Dynaudio whose speakers are more on the inefficient side of the spectrum. Is it possible that their reasoning has less to do with cost (they can always pass on the cost) or precision (I’m sure they have the manufacturing prowess to address precision), but maybe they feel that less efficient speakers bring something to the table that higher efficiency ones cannot? In other words, it could very well be a conscious design decision driven by the type of sound they’re aiming for and not necessarily cost.

AFAIK, other brands like Magico also make speakers that are not particularly efficient. Again, I find it difficult to assume that cost or lack of precision is what’s driving their decisions.

Lastly, I have heard high efficiency speakers at several dealers and always assume they know how to set it up properly. You might still be right that maybe they were not positioned in the most optimal manner. But this begs the question, what makes it more difficult to set up high efficiency speakers? That seems to be a disadvantage to me at least.

why do companies continue to make speakers below 89-88db? Is it just a conspiracy to sell mega-bucks amplifiers?

Also, for some reason I have never met a high sensitivity speaker that I like. I listened to a bunch of Klipsch Heritage speakers (except LaScalas), Devore Orangutan 0/96, JBL. etc. I cannot put my finger on it, but there's something about low sensitivity speakers that pull me in much more so than the high sensitivity ones. I'm sure I'm not the only one, otherwise why would anyone ever buy them.

Drivers with low efficiency are a lot easier to make since they need less precision in the voice coil gap. So its easier to make money and solid state power is inexpensive, so this works for many manufacturers.


The only problem is that low efficiency speakers are inherently less dynamic, owing to a thing called 'thermal compression'. This is the quality of the voice coil to heat up in an instantaneous fashion, preventing the amplifier from making as much power since its impedance of the voice coil goes up with the heat.


This is easy to hear and easy to measure.


My surmise is you've not heard a higher efficiency speaker set up properly. When that happens you get no less resolution (often more) and no more coloration. My speakers (Classic Audio Loudspeakers model T3-3) go down to 20Hz flat; they are 98dB and 16 ohms. You don't need a lot of power to make them play- 50 watts is usually far more than enough. This is easy for both tube and solid state amps. The higher impedance allows all amplifiers to have audibly and measurably less distortion. 'Audibly' because the most audible distortion is higher ordered harmonics and intermodulations; small reductions of that result in smoother more detailed sound. 

^You’re not the only one. I feel the same way.

So the million dollar question is that if high sensitivity is the way to go, given that such speakers give you the freedom to pair with low watt amplifiers, why do companies continue to make speakers below 89-88db? Is it just a conspiracy to sell mega-bucks amplifiers? 

Also, for some reason I have never met a high sensitivity speaker that I like. I listened to a bunch of Klipsch Heritage speakers (except LaScalas), Devore Orangutan 0/96, JBL. etc. I cannot put my finger on it, but there's something about low sensitivity speakers that pull me in much more so than the high sensitivity ones. I'm sure I'm not the only one, otherwise why would anyone ever buy them.

Am I wrong to think tight bass is a clean bass without being boomy?

Clearly its a word that has different definitions with different people.

Am I wrong to think tight bass is a clean bass without being boomy?

I prefer dry vs warm or fat. I boost below 70 hz up to 5 dB leaving 70 to 140 at 1dB or 2dB down. You could say I am boosting what you feel relative to what you hear. I think my version of "dry" bass is what people interpret as "tight". 70 to 140 Hz are the "warm" or "fat" frequencies. This is an example of why high resolution room correction is such a great teacher. In playing around with a system's frequency response you learn what various modifications do to affect the sound. On top of this you have distortions created by the woofer and enclosure which can not be corrected such as port noise. 

I think many associate tight bass with speakers that don't go very low, and many times this is very efficient low xmax woofers.   Much more to it than what I am pointing out here, but this thought process persists. 

In general,  low bass extension comes at a cost and that is Sensitivity.  This is only a generalization, overall, the balance of mass vs motor tells the story, but regardless of the woofer,  anytime that you add mass, FS goes down and so does Sensitivity.  

I think when many people refer to “tight” bass they are trying to express a juxtaposition to the perhaps more common “loose bass”.

Its a good point. I've just not heard 'tight bass' in real life, only in stereos.

I think when many people refer to “tight” bass they are trying to express a juxtaposition to the perhaps more common “loose bass”.
 A sealed box will often provide tighter bass than a ported box, but if comparable bass output is to be achieved, the sealed box will typically do it with less efficiency.

'Tight' bass is a coloration and has nothing to do with efficiency.

“Tight” bass no. But efficiency and box size have a relationship for deep bass. The pressure increases faster in a smaller box and the driver has to work harder to overcome it. 

Not many things in audio depend on just one other thing. Being connected, most things depend on being connected to something. But there must be at least a half a dozen things I have done that have made the bass tighter and more articulate but had nothing to do with efficiency. So the answer is no.

No relationship at all. 

For drivers, no, but in speaker design you can often trade sensitivity for deeper bass. Less sensitive = deeper bass.

A great example of this is the Magico S1 Mk II, which is pretty inefficient (86 dB) but achieves remarkable bass for the size.  (sits back and waits for the Magico shills to go absolutely bonkers).

NO! The bigger the magnet ... stronger magnetic flux to control the voice coil's movement in the gap. Altec's and JBL's of yore were noted for this aspect!