OB bass surprise

[bigwill]

I was repairing a pair of 70s three ways today. I had the woofers out running full range on the floor to identify why exactly one of them was distorting massively despite it not rubbing at all. I propped the working one up vertically and was surprised at the sudden amount of bass coming from a 10" speaker with absolutely no baffle or bass boost whatsoever! It didn't go particularly deep but it was definately there and very listenable. As usual with OB bass it was tight and musical. I don't know the Qts or Fs of these drivers but they seemed to work well. Another interesting thing I noted was that there wasn't a bass null at the edges of the driver.

I don't know why these drivers in free air without baffles made so much bass, but I can't wait to try this with some 18" woofers (with a baffle though)

OB speakers are really great and I think they are a great way for a newbie to make something great sounding!

Why is it that theory predicts depressing bass response from OB speakers and yet many people seem to experience the opposite?

 

[adason]

Another interesting thing I noted was that there wasn't a bass null at the edges of the driver.

i do not believe that

Why is it that theory predicts depressing bass response from OB speakers and yet many people seem to experience the opposite?

its not just theory, it's hard reality, sorry to disappoint you


some points:
what you might percieve as bass might be actualy lower midrange
use 30-50 Hz sine wave and compare OB and closed box and you will be cured
the amount of bass might be there when you are holding the woofer onfront your head
try to hang in the ear and go couple of meter away and you will notice lack of bass
the other thing is try to overload them and you will see how little they can handle if no box is behind to work against

nothing against OB, been there done that, but once you pass the first infetuation, you will realize its best used for midrange
its hard to do right for real bass

 

[bigwill]

can you feel midrange?

 

[adason]

you can feel anything if you are sensitive enough
lower bass is 20-80 Hz
upper bass 80-300 Hz
lower midrange 300- 800 Hz
(approximately, depends on which book you use as source)

if you can feel lower midrange? most definitely!
ask a drummer!

use sine wave generator and see for yourself
have fun

 

[bigwill]

I am a drummer

 

[DougL]

Why is it that theory predicts depressing bass response from OB speakers and yet many people seem to experience the opposite?

The simplest model for OB predicts roll-offs that simply don't happen. If you use one of the applications that calculates base more accurately, you will see how flawed the simple model really is. XLbaffle is what I use currently.
I understand that Martin King and JohnK both have programs useful to this.

Bottom line, you are not crazy, the world is not a simple place.

HTH

Doug