Sub design

[billnchristy]

I moved my wonderfull little Altec Lansing 2.1 system(circa 1998) out of the living room because the ugly off white doesnt match the new paint and bookcases.

I missed the punchy little sub after installing a pair of woefully unmusical Sony bookshelves I had bought years ago and never used (now I know why!)

So I got busy hacking up some old bookshelves this afternoon and made a small box for an old JL Audio 6.5" mid bass. I also ordered a small 25w plate amp for it (This "system" is only used to listen to rhapsody upstairs and not loud).

Anyway...long story short...sounds decent, have bass now.

I used to design boxes for a car audio store and have built everything from transmission line, to bandpass to some ridiuclous triple tuned boxes.

The big question is, why no sealed sub systems for home? I dont know if there are any, but there sure aren't many. I would think for a big dollar set up with big wattage a nice fat 12" with plenty of juice would be WAY more musical than a boomy ported setup.

I am guessing the average output just wouldnt be up to snuff.

Anyone have any funky setups in their system?

 

[WmAx]

I moved my wonderfull little Altec Lansing 2.1 system(circa 1998) out of the living room because the ugly off white doesnt match the new paint and bookcases.

I missed the punchy little sub after installing a pair of woefully unmusical Sony bookshelves I had bought years ago and never used (now I know why!)

So I got busy hacking up some old bookshelves this afternoon and made a small box for an old JL Audio 6.5" mid bass. I also ordered a small 25w plate amp for it (This "system" is only used to listen to rhapsody upstairs and not loud).

Anyway...long story short...sounds decent, have bass now.

I used to design boxes for a car audio store and have built everything from transmission line, to bandpass to some ridiuclous triple tuned boxes.

The big question is, why no sealed sub systems for home? I dont know if there are any, but there sure aren't many. I would think for a big dollar set up with big wattage a nice fat 12" with plenty of juice would be WAY more musical than a boomy ported setup.

I am guessing the average output just wouldnt be up to snuff.

Anyone have any funky setups in their system?

Ported systems are far more practical/cost-efficient, as they are able to produce a greater practical low frequency limit and SPL with lower distortion, when compared to an equivalent sealed system. A sealed system is fine and all, but to reach the same approximate LF output in conventional systems, you need to double the number of transducers as compared to a well engineered ported design. Obviously, applications where cost and other parameters are not tightly regulated, a sealed system is not out of the question. BTW, a ported system is not inherently 'boomy'; boominess, the cause of which, is a combination of variables that are commonly misinterpreted.

-Chris

 

[j_garcia]

Boomy would suggest nothing more than a poorly designed sub, or possibly a poorly placed/calibrated sub. You haven't listened to enough good subs if you think ported is going to give you boomy...

There are a number of sealed home subs out there, you just have to shop around.

 

[billnchristy]

I dont necessarily think ported designs are boomy, but by nature you are making a dB hump somewhere in the freq. range when you tune your port. If you are making a dip then I would not consider it a very well designed box.

It does seem to me though that the sound from a ported box is much more suited to a movie type enviornment where most of your output is pretty much noise anyways.

I would probably port this box too if I could find the specs for the speakers, but they are so old I am not having any luck. JL used to have a good archive but it seems to have disappeared.

As far as not hearing enough good subs, for home, you're right. I haven't heard many at all. A poorly designed car sub can still sound ok when put in the peaky bass enviornment of a car, not so at home.

 

[j_garcia]

See, that's where some of the internet direct companies really come into play. Probably some of the best subs out there right now, IMO, are mostly vented designs. In fact, in the home, sealed creates different issues - in a small volume with cabin gain, sealed subs generally sound good. Stick them in a large volume area with less gain and you now need a TON more power to achieve the same thing that a vented design can do easily. Vented designs aren't quite as "tight" as sealed, but that is one of the trade offs, as are output, tuning and extension. Peaks and dips can be due to the room as well, so even with a relatively flat response designed into the sub, the result will vary depending on the room. Then you can get EQ involved...