Loudspeaker volume

[nomis514]

Here is a visualization of hoffman's iron law:
Vb vs F3 plotted for 4 different sensitivities: 84, 87, 90, 93 dB

Note that you can gain 3dB in sensitivity by increasing box size by 2, or by increasing F3 by 1.26 times. In order to have a lower F3 and a larger sensitivity, you must have a larger box.

This is what is meant by low F3, small box, high sensitivity, pick 2.

If you want high sensitivity and low F3, you need a big box
If you want a small box and a low F3, you need low sensitivity
If you want high sensitivity and a small box, you need a high F3.

Oh wait in your graph, can we imagined those 4 curves being 4 different woofers?

 

[planet10]

Ok let's say I want : "A small box and a low F3, you need low sensitivity" How can I achieved this? I guess have to replace the woofer right? That's why I asked earlier if it would be possible to find a woofer of "better quality" to cope for the lost in sensitivity and get bass extension.

Yes, one would choose a different woofer… wher eyou end up as far as Hoffmann goes starts with choosing the appropriate woofer.

dave

 

[Ron E]

Ok let's say I want : "A small box and a low F3, you need low sensitivity" How can I achieved this? I guess have to replace the woofer right?

Or you could add a series resistor or add mass to the woofer. You could do it temporarily with magnets.

That's why I asked earlier if it would be possible to find a woofer of "better quality" to cope for the lost in sensitivity and get bass extension at the same time.

Ok, lets pretend this makes sense. How would you do that?

Oh wait in your graph, can we imagined those 4 curves being 4 different woofers?

I am trying to bring you along on this ride, otherwise I wouldn't have spent 2 hours making the graph for you. Each point along those lines are some woofer with that sensitivity. You can see they don't cross, so you can't
"

...find a driver that is more efficient by 3db than the one I have on paper and with a smaller F3, would it be more sensitive in the same enclosure?

"

I think you need to go back a couple steps so we can answer your real question. Why the dissatisfaction with the PL woofer? What led you to the decision to replace it? etc...

 

[nomis514]

I think you need to go back a couple steps so we can answer your real question. Why the dissatisfaction with the PL woofer? What led you to the decision to replace it? etc...

Lately I bought a node2 and I am listening to MQA. It improved a LOT the sound, much more detail and presence than MP3 from Chromecast. Still I feel like my bookshelves speaker are unbalanced, especially in the mid and low. That's why I suspected the crossover in first place and slip to that discussion of replacing the woofer. The Hoffman law is very good to know and I appreciated the time you took to explained it to me. What I'll do is proceed with some reverse eng. of my speaker and to provide exact infos about the drivers, crossover, volume. I'll come back to you. Might take a week.