Sealed or Vented????

[River757]

I see the word "boom" used a lot in this discussion - can someone define it? Because to me boom usually means a speaker that lacks enough cabinet damping material, leading to an overadundance of internal reflections & causing bass notes to become indistinct.

 

[weltersys]

I see the word "boom" used a lot in this discussion - can someone define it? Because to me boom usually means a speaker that lacks enough cabinet damping material, leading to an overadundance of internal reflections & causing bass notes to become indistinct.

That would be one definition, though at frequencies below 100 Hz, damping material has much less effect than cabinet design.
"Boom" also refers to a narrow peaking response caused by a "too small" sealed enclosure, or certain BR alignments that cause a narrow peak at Fb (box tuning).

 

[puppet]

... or is the additional dampening material increasing the Vb the driver sees? To me, the "boom" effect comes about from the peak in response just before the driver falls off in the low end. The low frequency harmonics probably work to exaggerate the effect in this region as well. As pointed out earlier in the thread ... some rooms might work OK ... while others might not.

A guy should knock a box together first to simulate real conditions. Can't miss that way.

edit: ^ I type slow

 

[Richard Ellis]

I'm siding with the sealed camp....the EBP at 44 puts it in the sealed type far more than the vented alignments. I get 4.320977846 cubic feet sealed....with the Fs way down at 19Htz & your Qtc set at .707, this will get WAY down there!
The only downside is your enclosure being as big as it is...attention to construction techniques is crucial. Using nice thick materials, like the common MDF must be at least One inch thick. One big & heavy box...........but well worth it!

______________________________________________________Rick.......

 

[Jay]

What I've learned while reading all of the responses to this thread is 30% of driver and cabinet selection is sound engineering best practices, 70% is personal preference.

What I don't understand is whether those percentage numbers are based on sound engineering practice or personal preference

Yes, there is personal preference between vented and sealed. It is basically based on personal priority scale on important attributes associated with certain box type (such as the "transient" for sealed).

The most important attribute of vented is actually its ability to reproduce lower frequencies. So when you can get a 40Hz or acceptable frequency by your standard (and acceptable SPL) with any box type, vented has almost no benefit.

Other attributes such as ease of design, build size, sensitivity, etc are not as important as the transient and roll-off frequency imo.

 

[Richard Ellis]

Vented alignments do not 'go lower' than sealed, rather, once the vented alignment drops below Fb the curve is steeper @ 24 Db per octave than the sealed that drops 12 Db per octave. Since the EBP value is at the sealed range of values.........it should be of the sealed type. Now, if the driver selected had an EBP of 91.5......that would put it in the vented type.

_______________________________________________________Rick.........