# hlcd shape



## cheebs (Apr 3, 2009)

are all of the car hlcd the same basic shape and size ? what are the other shapes and sizes if any?


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## cheebs (Apr 3, 2009)

nobody? is the image dynamics horn the best horn? are there budget horns? what horn has the best detail?


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## minbari (Mar 3, 2011)

I think they are all the same basic shape in very general terms.

The three that are used most are probably:

Image dynamics (Eric Stevens)
USD
Veritas

They all have slightly different characteristics. From frequency response to dispersion patterns. The model of compression driver and xover point/slope has an effect on it too. I am not sure there any "best" out there, some just perform better than others.


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## Eric Stevens (Dec 29, 2007)

cheebs said:


> are all of the car hlcd the same basic shape and size ? what are the other shapes and sizes if any?


All of the under dash horns have a similar footprint / size. The horns throat shape and design details have a significant effect on the frequency response and sound quality. Even though they are similar in shape they can vary dramatically in sound quality. IMHO the horn is more important than the driver until you are comparing two well executed horn designs. For example an average compression driver on a good horn will sound considerably better than the best compression driver on a poor horn. 

Underdash horns are designed to produce a sound stage for both front passengers by minimizing the path length difference between left and right speakers and compensating further with pattern control that produces a higher output/loudness towards the opposite listener to use volume to overcome the early arrival of the closer side.

Eric


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## [email protected] (Mar 19, 2012)

Eric hi,

We used to distribute ID in the UK, sorry to read about everything that's happened and wish you every success for the future.. and Matt as well.

I always meant to ask, but never got round to it, but:

On the large format lenses the driver fires straight into the horn, on the mini, that flare is bent (if you know what I mean) - does this make a difference? I always felt the mini's imaged better, and thought it may be because of this bend.

Also, most horns have an initial flare, and then a secondary flare to the mouth what is the importance of the shape of the flare - I mean, looking at it it makes sense, but it must be more tech' than that?

Kindest,

Matt


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## Eric Stevens (Dec 29, 2007)

[email protected] said:


> Eric hi,
> 
> We used to distribute ID in the UK, sorry to read about everything that's happened and wish you every success for the future.. and Matt as well.
> 
> ...


Hi Matt

All is well, thanks for the wishes.

The MH have a harder cross fire pattern which is why they more easily create a focused center image.

The shape of the flare controls loading or acoutical impedance of the horn as well as the pattern control/dispersion pattern of the horn. Different parts of the horn have effects over different parts of the frequency specturm of the horns useable bandwidth. Like all engineering its finding the right balance, its much easier to design a round horn or a horn where pattern control isnt a concern.

Eric


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## [email protected] (Mar 19, 2012)

Thanks Eric, that's what I suspected, the proper articulation and terminology certainly helps


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## Patrick Bateman (Sep 11, 2006)

cheebs said:


> are all of the car hlcd the same basic shape and size ? what are the other shapes and sizes if any?


It's pretty easy to build your own waveguides.
Waveguides generally have straight or close to straight side walls.
Due to the simple geometry, one can build one in about an hour.

It's a great way to learn how horns and waveguides work, and I'm surprised more people don't do it.

In particular, when you build your own you can get rid of the 90 degree bend that exists in the Veritas, Image Dynamics, and USD horns.

Another option, if you don't want to build your own, is to buy a commercial horn and chop it down to size. Here's why this is easy/effective:

1) A horn provides directivity and gain for a compression driver.
2) high frequencies are very short. For instance, 10khz is 3.4cm long.
3) Because high frequencies are so short, you can remove as much as half of a horn body and it will still work. In fact, you may reduce the bandwidth by only 20%.









For instance, the horn in the middle is about 15cm deep.
If you cut it in half, it will be 7.5cm deep.
You'd think that would cut it's bandwidth in half, but it doesn't, because frequencies get longer as we go lower in frequency.
Due to that, the 'stock' horn, at 15cm deep, is good to about 566hz.
Chop the horn in half, and it's good to 1133hz.

*So even though the horn is now half as deep, and even though the volume of the horn is about 75% smaller, the bandwidth of the horn has only been reduced by one octave. It's gone from 5.5 octaves (500hz-20khz) to 4.5 octaves (1000hz-20khz).*

Even more impressive is that the *volume* of the horn has gone down by 75%, because it's expanding in two dimensions.

This 'trick' is especially effective if you push the horn into a corner.
There's a BMW with Image Dynamics horns that did this effect really well; basically the horn was almost flush with the firewall.


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## thehatedguy (May 4, 2007)

I wonder which/whose BMW that is?


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## roduk (Sep 19, 2008)

Interesting. I ran ID large bodies and absolutely loved them, then I got the opportunity to swap in a pair of Veritas bodies. I used the same drivers in both - B&C DE250's and the Veritas have more detail and depth, but a slightly narrower stage. The depth blows me away sometimes. I haven't even installed them properly yet so really look forward to see what will happen at the end of this road.. 

I had a small relationship with cone drivers between the two and I just missed the presence and reality that horns give. Some people say that horns are harsh. Bollocks.


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> I wonder which/whose BMW that is?












Mic Wallace I think? Very cool setup.


















Basically the same idea as what I did with the horns on my dash. But with a couple of enhancements:

1) If I get in car crash, I'll have a horn in my face, which is a very ironic way to die. If Mic crashes his BMW, he'll be fine.

2) I think that one great reason to put horns under the dash is that speakers sound better when you can't see them. It's the same reason that every stereo in the world sounds better with the lights dimmed. Our eyes 'tell us' where the sound is supposed to be coming from, so if you can hide your speakers it improves the imaging. This works in movies too, when you watch a movie your brain always 'steers' the sound towards what's happening in the picture. Last night I listened to Dolby's Atmos sound system, which has something like 30 channels, and it was a great example of how video trumps audio. (IE, it really sounded no better than 5.1 sound.)


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## thehatedguy (May 4, 2007)

Bummer, can't see the BMW picture at work...but I don't recall him ever having the horn that far under the dash. He did put them under the dash and built covers for them so they wouldn't be visible. I've stuck motors on some horns outside of the firewall.


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