Could you email me, please.

Thanks,

Bob

In Open Baffles, I think that Dick Olsher claims an efficiency for the DX4s of something like 98 db. In open baffles, I use a single inductor as a first order filter to roll off the high frequencies from 500 hz and above. I then have a fairly flat frequency response from 150 hz to the high frequencies (~10 khz).

In Hedlund Horns, the DX4s are flat all by themselves (no filter needed) from 70 hz to the high frequencies (~10 khz). Thus there are no losses in inductors, and I can get down lower.

Retsel

Rather than increase the efficiency of the upper registers, the BLHs don't use crossover components which REDUCE efficiency in other designs.

This is why BLHs are more efficient.

Retsel

No point in arguing semantics. The fact is that average sensitivity isn't increased. I'm not advocating any particular design, but I am saying that I think a physically small basshorn acts very similarly to a transmission line, and that they both act like tuned pipes.

At least, that's what I think this conversation is about.
Dave

Each will have Helmholtz resonance, determined by the dimensions of the exit hole and the volume of the cabinet. Helmholtz resonance is normally associated with bass-reflex speakers, but it is just a physical property that happens when you have a chamber with a hole in it. There will also be standing wave modes, determined by cabinet dimensions, component placement and geometry. And there may be some horn action, depending on flare rate and environment, like corner loading. So there will be each of these properties, whether the speaker is called a reflex system, horn or transmission line. The overlap of each of these makes them more similar than different.

When I was referring to BLH, I was talking about a horn loaded rear wave that should be corner loaded to get any real extension. These tend to have greater bass output. I realise that the short small opening horn typically found on BLH's and almost all FLH's that are designed to be placed farther into the room (typical "audiophile" regulations ) aren't really any more efficient in the bass than any other type of box. I do find the actual sound to be typically a bit different, though, so I suspect there's something going on that makes a difference between the different type of bass boxes, but don't ask me what, as I'm not any kind of engineer. I just listen. Maybe I haven't listened to enough variety yet. I'm always open to people sending me (or stopping by with) different speakers so I can broaden my experience.

Dave