Compression drivers?

[Plcamp]

I like the response of the RCF ND650 in the factory datasheet better, and I guess would consider the poly surround a plus. Among others the Lavoce HD1403 horn looks nice, 80deg horizontal, the B&C ME90 is nice as well.

As far as I can tell, nobody anywhere in Canada sells RCF, except for finished speakers. Same thing with most CD’s. Can’t buy them anywhere I can find. At least Solen covers SB audience.

Edit: LOL Solen.ca site is down today.

 

[DanielT]

General tip, Parts Express seems to have a lot of stuff regarding compression drivers, horns and waveguides:

Home

Browse our comprehensive selection of compression drivers. Pair up with a horn or waveguide to fulfill your high-powered midrange or high-frequency live audio needs.

www.parts-express.com

Home

Explore our stock of horns and waveguides. Find the partner for your horn driver to deliver midrange and high frequencies, with reliable range and coverage.

www.parts-express.com

 

[Plcamp]

Parts Express

It’s interesting that if you look at PE’s horns available, there are few with much difference between horizontal and vertical dispersion. And most seem to want to illuminate a quite narrow front lobe if you inspect the data sheets.

I think (because I am dangerously semi educated with little listening experience of horns) I want something like a 90(min)x40 to keep a wide enough LP without excessive reflections from lowish ceilings.

 

[gy-k]

I'm not an expert either. Which geometry does wide horizontal and narrow vertical nicely? I vaguely recall that Greg Timbers said that the vertical orientation of the biradial horn on the JBL Array 1400 is actually the right orientation, something along those lines.

For example Limmerhorns makes horns that have wide horizontal and narrow vertical, like 90x40, https://www.limmerhorns.de/übersicht/
But on those ones you can notice the diffraction slot and ripple in the FR, if I'm not mistaken.

The B&C ME90 is available on PE, it has quite smooth curves, except the edges, as usual. There's a number of tests in Voice Coil Magazine with it, including the B&C DE680TN which is in the same 2.5" dome category, and the Radian 745NEO aluminum dome, which is something different. Joseph Crow actually had and tested RCF on his own horn design here http://croweaudio.blogspot.com/2019/11/es-600-biradial-horn.html

 

[DanielT]

It’s interesting that if you look at PE’s horns available, there are few with much difference between horizontal and vertical dispersion. And most seem to want to illuminate a quite narrow front lobe if you inspect the data sheets.

I think (because I am dangerously semi educated with little listening experience of horns) I want something like a 90(min)x40 to keep a wide enough LP without excessive reflections from lowish ceilings.

Basic question. What does 90x40 mean?

Or wait, I'll take an example at random..:
"90°H x 40°V nominal dispersion"

What is nominal dispersion?

"Nominal Dispersion: 90°H x 40°V"

Okay but in practice, listening distance 3 meters, 10 ft so 90°H x 40°V" means what? 90°H calculated how? 45° on both sides? What will be length and width in listening position be before the sound image collapses?

 

[Duke]

Basic question. What does 90x40 mean?

Or wait, I'll take an example at random..:
"90°H x 40°V nominal dispersion"

What is nominal dispersion?

"Nominal Dispersion: 90°H x 40°V"

I would take that the mean, the average dispersion across the frequency range of the horn is 90 degrees wide (-6 dB @ 45 degrees off-axis to either side) in the horizontal plane, and 40 degrees wide (-6 dB @ 20 degrees off-axis above and below) in the vertical plane.

 

[Jon AA]

I would take that the mean, the average dispersion across the frequency range of the horn is 90 degrees wide (-6 dB @ 45 degrees off-axis to either side) in the horizontal plane, and 40 degrees wide (-6 dB @ 20 degrees off-axis above and below) in the vertical plane.

Yup. That seems to be the industry standard most use.

 

[valerianf]

"It makes not much sense to put a expensive high efficient driver in a system and then castrade them with resistors. At least not for me."
There is a very obvious reason: lowering distortion when SPL output is going up.
It is an evidence with the tweeters: a dome or ruban tweeter will be damaged before reaching a level where the compression tweeter has very little distortion.

 

[fluid]

What is nominal dispersion?

To add to the other replies, it can really mean anything as it depends a lot on whether the horn/waveguide has a flat or rising DI. By way of example a Faital LTH 142 is listed as 60x50, it certainly is 60x50 somewhere but not everywhere. It is about as useful a specification as +/- 3dB. Look for beamwidth charts or polar graphs to see the pattern. When a device is asymmetric the vertical pattern control will be lost higher in frequency than the horizontal because the vertical dimension is shorter. You can see this in the graph below where the vertical gets wider more quickly as frequency goes down. This is called pattern flip, where the supposedly narrow vertical becomes wider than the supposedly wide horizontal.

Okay but in practice, listening distance 3 meters, 10 ft so 90°H x 40°V" means what? 90°H calculated how? 45° on both sides? What will be length and width in listening position be before the sound image collapses?

There is not a defined pattern where you will fall off a cliff once outside, the sound will be most consistent within those angles

 

[Newman]

Yes, that is a more realistic definition. The idea that the beam width "is" 90x40, or even "averages" 90x40, across its frequency range, is hiding a lot of sins.

Side note: for a conical horn, a listing of "90x40" can be simply the angle of the walls.

 

[DanielT]

Tip:

Horns by Auto-Tech – acoustic horns, waveguides, casings and ready-made loudspeaker systems

An example, if you like that kind of sound propagation:

TRACTRIX-200 – Horns by Auto-Tech

... Or:

SEOS-15 – Horns by Auto-Tech

I don't know their prices. Company is located in Poland

 

[Flaesh]

their prices

DSG was their dealer and there was an American price. IIRC SEOS was about $2xx\pcs
I bought mine used, about €2xx\pair

 

[hex168]

DSG was their dealer and there was an American price. IIRC SEOS was about $2xx\pcs
I bought mine used, about €2xx\pair

The SEOS 15 is sold by diysoundgroup but they have been out of stock due to supply chain issues. The old price was $36 each:

Denovo Audio SEOS-15™ for dome tweeters

Denovo Audio, SEOS-15™ waveguide, dome tweeter waveguide, horn, SEOS Project, SEOS waveguide

www.diysoundgroup.com

That waveguide is used in this speaker and tests very well indeed (particularly normalized horizontal beamwidth, which is what would apply after EQ):

DIYSG HTM-12v2 Speaker Review

DIYSG HTM-12v2 Speaker Review

www.erinsaudiocorner.com

 

[Duke]

View attachment 231141
View attachment 231142

SEOS-15 – Horns by Auto-Tech

I chose the DIY Sound Group molded plastic version for this speaker; the fiberglass version made in Poland is even better looking:

 

[voodooless]

The SEOS 15 is sold by diysoundgroup but they have been out of stock due to supply chain issues.

I think they have been out of stock for years. I would not hold my breath for one of these.

 

[DanielT]

I think they have been out of stock for years. I would not hold my breath for one of these.

But doesn't AUTO-TECH own the design for SEOS 15? Isn't it their own construction? If so, they have the machines to make them. If the demand is there, that is. Or?

AUTO-TECH manufactures acoustic horns, waveguides, casings and ready-made loudspeaker systems for various applications.

A wide range of various acoustic structures and extensive experience of our designers enable us to complete projects for the most demanding customers.

At the same time, we are able to complete customized projects because we have the possibility of using our CAD/CAM technology and CNC machines as well as our own tool shop.

Horns by Auto-Tech – acoustic horns, waveguides, casings and ready-made loudspeaker systems

But maybe it's not that simple, very possible that I missed something here? In any case,you can always ask them.For those who are interested, in need of a pair of , for example SEOS 15.

 

[DanielT]

When I checked AUTO-TECH's website, I discovered that they also manufacture speakers.

Present regulation describes the rules of buying on-line on www.horns.pl and www.horns-diy.pl
products by AUTO-TECH and it is available on websites given above.

TERMS AND CONDITIONS – Horns by Auto-Tech

Here is an example of one of their models:

FP15 MK 2 – hORNS

horns.pl

 

[voodooless]

But doesn't AUTO-TECH own the design for SEOS 15? Isn't it their own construction? If so, they have the machines to make them. If the demand is there, that is. Or?

I’m pretty sure they will have the horn. It’s way more expensive however than the the sold out Denovo version.

 

[Flaesh]

I’m pretty sure they will have the horn. It’s way more expensive however than the the sold out Denovo version.

Write to them and find out the current prices and terms of production.
Fiberglass is way more expensive than plastic.

 

[hex168]

If I recall correctly, the SEOS profile was a group effort led by Erich H of diysoundgroup. See here:

https://www.avsforum.com/threads/hey-guys-we-need-a-little-rallying-here.1291022/

Autotech was used as the manufacturer of the larger SEOS waveguides in fiberglass.