Bass Extension?

[johnr66]

I built a set of speakers for music listening. I wanted a small to medium sized speaker at around 1.5 cu/ft. Using WinISD, I entered the parameters of several drivers and finalized the design with an F3 at 50Hz with a good driver. I figured this would be good for classic rock and 60's music (among other things).

Now, testing the speakers with sine wave tones, I walk around the room and at 40Hz sounds as strong as 50Hz. Even 35Hz sound strong and it tappers off down to 30Hz where there is still some fundamental output but it is weak.

While I'm please to have this bass extension, I wonder why I am getting this from the speakers that were designed for F3 at 50Hz?

While were at it, is there a definition of bass extension? My search come up empty. Would it be from the 3db down point to??

Thanks!

[steviedon]

Room gain, I'm guessing it's a fairly small space.

As far as bass extension....it's debatable for sure. F10 is usually the cutoff for me, as in usable extension.

[Dave Jones]

My satellite speakers have an F3 of 80Hz in theory, but in my 18x18 ft living room they are too loud at 63Hz and require EQ to cut it back. (Eighteen feet is the wavelength of 63Hz.) I am crossing them over to the subs at 60Hz. In a different room, I crossed them over at 100Hz.

[johnr66]

The shape of the room is is kind of complex as it is an L shape. The room is 17x12 ft, but the 8 x 12 dinning area makes part of the room 24' wide. Off from the dinning room is the kitchen that makes the whole thing an uneven U shape. The room is acoustically neutral with wall to wall carpet, sofa and other furniture.

I know that placing the speaker in the corner make the bass louder, but not necessarily lower. So the the room can also extend the response down by that much?

[steviedon]

Well, guessed wrong as it seems. Are the speakers positioned along the 12ft wall.....as this could validate the extension gain. Of course this is all speculation until we know the intricacies of the speaker.

Whatever the reason behind it, I'd be happy if in your situation, as you've (from your description) achieved more than adequate extension out of your 2 modest sized speakers for most music. On a side note, while the room modes you're experiencing now are no doubt positive, it could pose some problems if you add a sub later down the road for that last bit of extension......but still easily remedied by crossing it low. Your situation is good.