Tapped Horn and Driver resonance Freq.

[MaVo]

Originally posted by AndrewT
the benefit of the horn is that it can approach 50% efficiency in the passband.

I don't think there is any bandpass or vented or sealed enclosure that can achieve that.
Maybe you can point me to a paper that shows how these "boxes" can approach 50% efficiency in the passband.

Sorry, i think i wasnt clear enough on this. If you take a tapped horn and make the mouth very small, lets say 1-2 times the membrane area, then its behaviour is close to a BP6. If you make the mouth big, the effects of horn loading get more pronounced. You still need to have a full sized mouth to get to 50% efficiency with a tapped horn, just like with every other horn. The advantage is a flat response with small mouth size. This gives you more options to tailor a subwoofer to your needs, but it doesnt make it more powerfull than the other enclosure types. Output per volume for a given driver type should be the same no matter what enclosure type you choose.

[AndrewT]

Originally posted by AndrewT
Is the small volume of the TH also at the expense of efficiency?

You still need to have a full sized mouth to get to 50% efficiency with a tapped horn, just like with every other horn. The advantage is a flat response with small mouth size.

this seems to be confirming my question/answer.

[GM]

Originally posted by AndrewT

Is the small volume of the TH also at the expense of efficiency?

Correctomundo, no matter the internal configuration, net box Vb sets the max acoustic gain over whatever BW it's configured for.

GM

[iand]

Originally posted by MaVo



Sorry, i think i wasnt clear enough on this. If you take a tapped horn and make the mouth very small, lets say 1-2 times the membrane area, then its behaviour is close to a BP6. If you make the mouth big, the effects of horn loading get more pronounced. You still need to have a full sized mouth to get to 50% efficiency with a tapped horn, just like with every other horn. The advantage is a flat response with small mouth size. This gives you more options to tailor a subwoofer to your needs, but it doesnt make it more powerfull than the other enclosure types. Output per volume for a given driver type should be the same no matter what enclosure type you choose.

True if the tapped horn is exponential (or hypex) to maximise efficiency near cutoff -- if it's conical (like most TH) then there's wasted volume near the throat and the acoustic impedance (which means efficiency) drops near cutoff.

In other words a full-size hypex FLH with 50% efficiency (same mouth size) is smaller and has flatter response than a conical TH with the same cutoff and 50% efficiency -- which is what Tom said, if you've got room for a full-size FLH (which few have for bass) then build one, if you haven't then build a tapped horn.

Ian

[JLH]

Originally posted by Bent
@JLH - If "you could hear the mallet hit the drum before the bass pulse" is that group delay or is that the way a drum actually sounds - I guess you probably should hear the mallet hit first ..?

Yes, you should be able to hear the mallet strike on good clean recordings. There should not be any distinct delay between the mallet strike and the bass pulse. It should just be on the leading edge of the bass pulse from the drum.

Rgs, JLH