# Speaker Surface Area

Discussion in 'Amps and Cabs [BG]' started by brock29609, Sep 30, 2003.

1. ### brock296094 strings, 2 wheels

May 11, 2003
Greenville, SC
I was curious about speaker surface areas for different cab combinations, so I calculated the following. Though I would share. I'm not even sure how important/useful this is, but I hear it discussed a lot...

2. ### miccheck1516Guest

Feb 15, 2003
emm, i dont think you did that, ive seen that before

3. ### brock296094 strings, 2 wheels

May 11, 2003
Greenville, SC
I calculated it in Excel, pasted it in PowerPoint, then saved it as a jpg. I'm not saying I'm the first person in the world to do this, just thought I'd share.

I just noticed that I left out 410 + 212 (probably my fav combination).

4. ### Petebass

Dec 22, 2002
QLD Australia
I must be honest, and I hope I don't come across as being nasty - what does this chart prove? I am of the opinion that speaker cone area on it's own tells you very little about what speakers sound like. I hear people tell me a 4x10 must have more bottomn end than a 15 because it has a larger speaker cone area - It's one of the most widely accepted pieces of marketing propaganda ever. There are so many other factors to consider I don't even know where to start. This may be true of some 4x10's and some 15's but not all. It's more complicated than that.

5. ### Johnny BoomBoom

Jun 8, 2001
Glasgow, Scotland
Here's just a thought! I haven't checked all of the tabulated results, but I'm guessing you used what is effectively the area of a circle to give the area of a cone (which is closer to what a speaker is).

This is probably a good rule of thumb - as I'm unaware of any information on depth of speakers (depth of cones?). I guess you can use the ratios of the respective combinations as a measure of how much air is being pushed - but what does it all mean?

Did a search on the old internet and found this as a possible equation for working out the area of a cone - but a spkeaer will probably be more complex, as it isn't always a true cone - probably a combination of a circle and a partial cone!

Acone = pi × r × (r + (r2 + h2)1/2)

So, total area is made up from the contributions from the radius and the hieght (or depth of the cone) as always accompanied by our old friend Pi!

6. ### alexclaberCommercial User

Jun 19, 2001
Brighton, UK
Director - Barefaced Ltd
If I'm not mistaken, what truly matters with bass reproduction is not the area of the speakers but the 'swept' volume of the speakers, i.e. the cone area multiplied by maximum excursion. This varies hugely even amongst speakers of the same size.

Alex

7. ### Joris

I agree.

There's so many factors involved to describe the performance of a speaker system, cone area or air displacement are only a few of them.

8. ### brock296094 strings, 2 wheels

May 11, 2003
Greenville, SC
All good points. Thanks.

...and, I have no idea what this proves. That's why I said "I'm not even sure how important/useful this is". Thanks for the replies.

9. ### bgavin

May 3, 2001
Orangevale, CA 95662
I have all this information in my spread sheet, for some 1100+ drivers.

Piston area is what you are trying to chart. This is the area of the cone that does the work, and is less than the nominal diameter. An estimation is the cone diameter plus 1/2 the surround. Most manufacturers publish this data, so it is easier to read their PDF than calculate it.

The end result of piston area is cone displacement. This is the part the does the work of moving the air. Area * Xmax = Vd (volume displaced).

To make the noise, you have to move the air. Cone movement increases 4x for every octave lower, at the same loudness. A 10" driver is fine at higher frequencies, but is plain out of excursion in the bottom range, due to limited Xmax.

10. ### bben

Feb 28, 2002
Santa Fe, NM
There was a chart something like this in Bass Player at some point during the last year. I wrote an email to them pointing out that the displacement of the speaker(s) (cone area times cone excursion) was much more important than surface area, but didn't get a reply.

11. ### Mike A

Oct 3, 2002
Kentucky
Thanks Brock.
I appreciate it, even if no one else does
(only other one I'd like to see is 6x10.)

12. ### brock296094 strings, 2 wheels

May 11, 2003
Greenville, SC
You're welcome. It would be equal to the 210 x 3.

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