robocop horny speaker

[fpitas]

I am really, TRULY NOT OBSESSED with this topic. Just academically curious about the venerable Cobraflex.

https://products.electrovoice.com/binary/ID30CT%20Engineering%20Data%20Sheet.pdf

The document above shows the FR (as the "fundamental" in a harmonic distortion plot) of a specific EV driver (University ID30C) on a Cobraflex III horn.

View attachment 314530

As the genie says in Disney's cartoon version of Aladdin:

Spoiler

EDIT: It's actually not too bad from ca. 300 to 3000 Hz. I suspect that those two notches are related to the folded horn configuration as @fpitas mentioned a few posts earlier.

And it's obvious they cared about the voice range, 300Hz - 3kHz. Outside there, you're on your own.

 

[fpitas]

Another caveat about old tech horns, compared to modern, is the wall damping. 511s are notorious for their ringing, but that doesn't mean their competitors were blameless. I filled the bells and coated the horn body heavily to get an inert structure acoustically,. I have to think these would need a similar treatment, maybe pot the whole thing.

 

[mhardy6647]

Oh.
@Andysu
The physics (and the mathematics) of horns has been worked out for a long time (seven or eight decades).

If you're really and truly interested in stuff like this,
Get the Book.
Read the Book.
Learn the Book.
Live the Book.

meanwhile, you might want to leaf through this:
(sorry it's an "http:" link and thus not secure)

http://unepassionaudiophile.fr/wp-content/uploads/2018/01/CONFERENCE-PAVILLONS-1.pdf

or this:

https://www.grc.com/acoustics/an-introduction-to-horn-theory.pdf

from audioXpress, 2008

 

[mhardy6647]

Thanks! I suppose were one determined, you could EQ it.

As it is sometimes said with respect to the art and science of idiot-proofing:

Never underestimate the ability of a truly determined idiot.

 

[mhardy6647]

Obsessed? Me?
Absolutely no intersection of those two sets in a Venn diagram.

In seriousness, I meant to check this site last night -- and forgot until just now.
This is reportedly from 1952.
Source:

New Page 1

 

[fpitas]

Well sheesh. Now I have an opportunity to scare more people with my alien robot monsters!

Even the local wildlife lends a hand. Erm, wing.

 

[fpitas]

Frankly, unless you're a masochistic, or just want to learn about horns, they are best avoided for casual use. Most people are more than happy with waveguides, which are enormously easier to design with. They have somewhat higher IMD, it's true, but the rest of the drivers have to match the horn IMD performance, or you're wasting your time.

 

[mhardy6647]

That's right - horns are hardcore.
Like jazz musicians and heroin.

(sorry... sorry!)

 

[fpitas]

Obsessed? Me?
Absolutely no intersection of those two sets in a Venn diagram.

In seriousness, I meant to check this site last night -- and forgot until just now.
This is reportedly from 1952.
Source:

New Page 1

View attachment 314546

Some interesting old stuff there. As a youth I remember watching out for Altec multicells hung up on a pole, used for PA use.

 

[TonyJZX]

this is the perfect thread topic for andy

what can be more thematic than theater and its use of hifi technology in story telling

some obvious ones are patrick bateman, the sopranos and a clockwork orange

 

[fpitas]

Something I'm (barely) old enough to remember. Once upon a time a lot of people didn't have home hi-fis worth much, and one draw of going to the movies was the relatively hi-fi sound.

 

[TonyJZX]

well i mean yeah

my parents didnt care about this kind of thing and there was a common thing where peoples' best sound systems... was the four speaker stereos in their cars... amfm cassette AND cd!

I think one problem we had is that most theaters here were by JBL... junk by loud

as long as dialog was clear and there was no static that's all they cared about

 

[fpitas]

well i mean yeah

my parents didnt care about this kind of thing and there was a common thing where peoples' best sound systems... was the four speaker stereos in their cars... amfm cassette AND cd!

I think one problem we had is that most theaters here were by JBL... junk by loud

as long as dialog was clear and there was no static that's all they cared about

I was lucky to live near theaters that had massive Altec multicells for midrange and treble.

 

[fpitas]

Frankly, unless you're a masochistic, or just want to learn about horns, they are best avoided for casual use. Most people are more than happy with waveguides, which are enormously easier to design with. They have somewhat higher IMD, it's true, but the rest of the drivers have to match the horn IMD performance, or you're wasting your time.

Since we're obsessing here, I'll explain horns vs waveguides as I view the subject. YMMV, some restrictions may apply, and all that.

A waveguide obviously guides the sound from a driver and establishes a polar pattern. A horn does that, but in addition loads the driver diaphragm far more than the bare driver. In my view that acoustic loading should extend into the stopband of the crossover at least one octave, and I try to make the HPF attenuation at least 20dB one octave below the actual crossover. The term "horn cutoff" applies here, but you have to be a little careful that the loading is still good down to the frequencies you care about.

 

[Neddy]

This is why I love ASR so much - and so don't miss the 'morning newspaper' much.
Horn-ay obsessions, and ! Allied Radio catalogs (which I used to study like they were HS math exams!), forsooth.

 

[fpitas]

This is why I love ASR so much - and so don't miss the 'morning newspaper' much.
Horn-ay obsessions, and ! Allied Radio catalogs (which I used to study like they were HS math exams!), forsooth.

Lots of other obsessing going on here too, but it's time horns got their turn in the barrel!

 

[mhardy6647]

Horny Science Review -- has a nice ring to it, doesn't it?

Horn[y].
Ring.
see what I did there?

EDIT: PS this thread is great!

 

[TonyJZX]

yeah the only reviews are of Klipsh


<shudder>

 

[DVDdoug]

In the 1970s, I worked for a company that rented PA systems (mostly for outdoors and mostly for speaking, not music). We had at-least a couple of those and several other horn speakers. I don't remember what drivers were attached. 10-20 Watts was plenty of power for a fairly-large crowd. Most of our setups were 70.7V and most of our speakers were connected to the 10W tap, or less.

It's amazing the efficiency you can get when you only need "voice quality".

 

[fpitas]

yeah the only reviews are of Klipsh


<shudder>

I think they're getting better. About time.