Why does a compression driver need a horn?

[Defo]

Probably a dumb question, but why does a compression driver need a horn?

[RobWells]

Because that's what it is designed to do - drive a horn.

[drewmc]

The horn is designed to do two things:
1 Provide proper loading for the CD
2 Provide the desired directivity or sound coverage
Without proper loading the CD will not achieve the designed efficiency.

[Defo]

Originally posted by drewmc
The horn is designed to do two things:
1 Provide proper loading for the CD
2 Provide the desired directivity or sound coverage
Without proper loading the CD will not achieve the designed efficiency.

So if a CD was to be used without a horn, the the sensitivity would just be lower, and dispersion would be more or less like a dome tweeter, just with higher sensitivity?

So theres nothing stopping a CD to be crossed to say.... a small 3 khz waveguide to get good sensitivity and controlled dispersion? Seems like a much better alternative to the regular dome tweeter...

[MaVo]

Only that a crossover around 3khz is said to be a bad idea, sound quality wise, since the human hearing is very accurate in this area. A waveguide for a 1khz crossover is also quite small and compression drivers are designed to go this low.

[Patrick Bateman]

Originally posted by Defo


So if a CD was to be used without a horn, the the sensitivity would just be lower, and dispersion would be more or less like a dome tweeter, just with higher sensitivity?

So theres nothing stopping a CD to be crossed to say.... a small 3 khz waveguide to get good sensitivity and controlled dispersion? Seems like a much better alternative to the regular dome tweeter...

A compression driver IS a dome tweeter. Except it's buried inside of a compression chamber, with a sophisticated phase plug on the other side of the diaphragm.

Without a waveguide, the frequency resonse of a compression driver will be terrible... You definitely need to use one.

[tinitus]

Originally posted by Defo


So theres nothing stopping a CD to be crossed to say.... a small 3 khz waveguide to get good sensitivity and controlled dispersion?

Seems like a much better alternative to the regular dome tweeter...

Could be, but you need a small sensitive pro mid, which mostly only does it down to about 400hz

Alternative to dome tweeter?
You will need a lot of attenuation best done actively
Or low gain power buffer amp

btw, Bastanis doesnt have any horn/waveguide, but is crossed very high

But why cross high when it easily go lower with rather small waveguide
I see that as the main advantage of a CD

[Patrick Bateman]

Originally posted by tinitus



Could be, but you need a small sensitive pro mid, which mostly only does it down to about 400hz

Alternative to dome tweeter?
You will need a lot of attenuation best done actively
Or low gain power buffer amp

btw, Bastanis doesnt have any horn/waveguide, but is crossed very high

The Bastanis has a short horn on the front, and no compression chamber. So it's a dipole tweeter with a horn on one side, but not the other. The horn side has a phase plug. Kind of an odd design, but sounds very good.

[tinitus]

Nice picture

I knew it would be commented when I said no horn
Im sure the rounded edge have some effect
But I guess its mostly phase related
But from picture tweeter frontplate could seem to have become thicker
I suppose its only the most expencive version with this dipole option

It the backside of CD diaphragm we see on picture?
I always thought the dipole action was achieved by additional driver

ehh, does that mean that the voice coil is mounted in front of the diaphragm says rear facing free voice coil, but its hard to see really

[Pano]

I've heard this backless CD as pictured. It sounds good and works well. There is a short horn on the front.

Also have run some other CD backless, the extra splash off the back can sound nice.