mahgister,
Yes, the room acoustics are fascinating to me even as a child. So, maybe understanding the room first, and then 'marry' a speaker to it?
Physics Question: Why does cabinet volume matter so much to bass response?
If you put the same 8' woofer into a bookshelf speaker or a floorstander, you will get a different frequency response. Does anyone know what's happening with the air pressure on the inside of the cabinet to cause this to happen? Does the woofer in the bigger cabinet have greater excursion, and therefore produce more amplitude?
mahgister,Yes, the room acoustics are fascinating to me even as a child. So, maybe understanding the room first, and then 'marry' a speaker to it? |
My understanding is that a larger cabinet will support a lower frequency response in the bass. The shape of that frequency response is also shaped by the design of the cabinet, i.e., whether it be sealed box or bass reflex (let's leave out the other designs for the sake of keeping this simple). As many of you already know, the sealed box design will make a slower slope in the bass response (although not as deep) than the bass reflex, which goes lower in frequency, yet at a higher slope than the sealed design. Given this, bass response is altered by the physical size of the cabinet. A smaller cabinet simply cannot load the woofer for lower frequencies. Of course, these factors much match the T/S parameters of the driver to begin with to make a reasonable bass response in the first place. A bigger cabinet allows for lower and possibly flatter response in general than trying to make a small woofer and cabinet do what it cannot. A popular trick used for smaller cabinet/woofer sizes is to make use of a bump usually at 100hz. It gives the likeness of more bass, a thump, if you will, but it is not ideal for my tastes. This is the case for passive speakers, but active speakers can use EQ in the signal to try and offset the limitations of the cabinet and driver. In the end, physics will rule up to the limits of the final product. |
Well, it is a marriage between the driver and its abilities, and the cabinet made for it. You play to that particular drivers' strengths. In general, the bigger the woofer the bigger the cabinet. Again, this is applying to sealed and bass reflex/ported designs. It isn't a matter of the woofer being able to play louder any more than the woofer is supported by the cabinet's extension of resonance that aids in the woofer's lower octave response. You want big low bass, you will be the most successful with a larger cabinet and driver, given a proper design. And then you will move air. |
Never knew much about them, but I remember seeing a driver that was mounted in a closet door. This was back in the 50's.
I agree that the volume of the cabinet will dictate the amount of air suspension that the woofer is given. It is also important to know that the cabinet volume will determine the resonance of the cabinet itself. Think of different sized bottles and the sound that they make when blown over. |