Starting my study on horns for compression drivers

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good morning a friend of mine wants to set up a small disco in his basement
He knows even less than me about hifi but he would like a speaker with a horn on the mid-highs and he asked me to study the horns
I have a really strange question but I have to ask it
I have identified three main elements in a horn Horn, magnet and diaphragm
In my opinion in order of impact on the sound the horn comes first then the diaphragm and finally the magnet
Am I right?
Another question What would be the best xover frequency for a 2 ways speaker with a 10" woofer ?
i see commercial speakers crossed very high at 5kHz Is it not too high ? is it the best choice ?
thank you very much
 
Hi thank you very much indeed I am confused about the size I cannot understand if they talk about the horn screw connection or the compression drive voice coil Fwiu driver with different coil size can have the same threaded connection for the horn
I need to know the best horn size for a two ways lets say In my mind the horn impacts much more on the system
I don't want to sound provocative but drivers with a big difference in price will sound pretty much the same on a same horn?
This is very fundamental to understand for me
The answer will give a direction to my research
Thank you very much again
 
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Compression drivers come in two styles - with flat flange (bolt on) and screw-on (1-3/8" diameter with 18 TPI thread).
Standard driver exits (= horn "throats") are: 1", 1.4" and 2".
Standard voice coils diameters (of the compression drivers) are: 1", 1.5", 1.75", 2", 3" and 4". There are models with 2.85" and 3.5" also.
Compression driver with 1-3/8" thread may have 1", 1.5" or 1.75" voice coil. Bigger is better, of course, at least for power handling.
Good and expensive drivers will sound much better than ordinary cheap driver - in the same horn! Good drivers have very low harmonic distortion and flat-ish, extended frequency response free from resonances.
 
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I recommend you and your friend go out to some local bars that have dancing in a room that is similar in size to your friends basement to see what equipment they are using. If the floor space is the same, pay attention to the ceiling height as well. If it is a small space you will find it is not pleasant dancing close to the front of a large speaker with a big horn driver. Great bass makes for a fun dance system. To avoid hot spots think about using several smaller wide dispersion speakers distributed around the room, with no speakers in one area for those that like it not so loud.
 
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Compression drivers come in two styles - with flat flange (bolt on) and screw-on (1-3/8" diameter with 18 TPI thread).
Standard driver exits (= horn "throats") are: 1", 1.4" and 2".
Standard voice coils diameters (of the compression drivers) are: 1", 1.5", 1.75", 2", 3" and 4". There are models with 2.85" and 3.5" also.
Compression driver with 1-3/8" thread may have 1", 1.5" or 1.75" voice coil. Bigger is better, of course, at least for power handling.
Good and expensive drivers will sound much better than ordinary cheap driver - in the same horn! Good drivers have very low harmonic distortion and flat-ish, extended frequency response free from resonances.
good morning first of all thank you very much for the kind and precious indications
I saw that there are thousands of combinations for drivers and horns
I'll start by showing the concept that inspires my research
https://www.blumenhofer-acoustics.com/Products/Products.php?lang=it

1731660638132.png


this two-way solution has several advantages
you can reduce and control the dispersion on the medium high for me a really important thing
you can have a really low distortion at 3 meters even with musical peaks of a certain level
you can use low-powered but good-sounding amps
The biggest issue is to establish the portion of frequencies to be reproduced by the horn
in PA speakers the woofer does up to even 5kHz
in the speakers above up to 2kHz

and here I'm completely at sea
once the crossover is established then you can select a suitable horn and driver
I really don't know what to do in short
 
Your right sonce that is a big journey. Yep buy something already made.save time,money,grief,frustration etc.
Hi thank you very much The problem is that my friend wants to use it also for music listening and watching concerts or movies
he does not want multichannel absolutely He wants to stay with a stereo system or at max 2+1 But much better a stereo
he is more on sound than effects
 
portion of frequencies to be reproduced by the horn
This is often dictated by both the horn size and the desire to maintain good dispersion across the full frequency range. It's normal for woofers/midranges to get more directional as frequency increases, and this happens at lower frequencies with larger drivers. This and other limitations make it difficult to use large woofers/mids at something like 5 kHz. Actually, many small modern woofers have trouble going that high.

The horns on the speakers in Post #7 look pretty small, which may be dictating a high cross point.

in PA speakers the woofer does up to even 5kHz
I'm not sure which PA speakers you are looking at, but the more common approach these days is to use a 10 or 12 inch midwoofer with a moderately sized horn and cross in the 2-3 kHz region.

Celestion has a few DIY designs on their site where they show all the relevant information to build them. They mostly use "build this" in their title, in case this link doesn't work in the future.

https://celestion.com/blog/?fwp_blogcat=cab-designs
 
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Hi ! thank you sincerely for the vey valuable advice and great link I have checked some prices They are ridiculously low 😵😊
now i have no excuse for not try them
I see many interesting project
Do you think that a 3 ways could a better approach ? always with a horn mid
 
A 3-way approach is typically good, though not necessarily all in one enclosure.

Without being very large, the mid/high frequency range in a speaker like this typically has high sensitivity (gets loud with relatively little power). For the low frequency drivers to match that kind of sensitivity and go very low simultaneously requires a large and possibly complex enclosure.

With amplifier power getting cheaper all the time and the availability of high excursion woofers, a more practical approach is to use separate active subwoofers crossed at around 80-100 Hz. This also makes it easy to add more subwoofers until you're happy with the output, lets you distribute the subwoofers for more even response through the room (if that's a priority), etc. If you get a subwoofer or subwoofer amplifier that includes DSP, you can also typically equalize the in-room response, which is also very handy.
 
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The biggest issue is to establish the portion of frequencies to be reproduced by the horn
No issue at all - any good compression driver will work flawlessly above 1500 Hz, so does many average-size horns. Those drivers and horns are not very expensive.
But anything below 800 Hz demands big and very expensive compression drivers and big and expensive horns. Midrange horn may use cone driver and can be build from plywood.
So, it is a no-brainer - crossover frequency for a 2-way loudspeaker should be between 1500 and 2000 Hz, depending on the compression driver.

in PA speakers the woofer does up to even 5kHz
You can find 5 kHz crossover only in low-quality, cheap PA speakers.
Decent 2-way PA speakers have crossover frequency around 2000 - 2500 Hz.

once the crossover is established then you can select a suitable horn and driver
First you choose driver and horn, depending on the budget. Then the crossover frequency naturally follows.
 
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a friend of mine wants to set up a small disco in his basement...

I would not expect two speakers each with a single 10" woofer to be sufficient for a "small disco in his basement", but that's just my opinion.

What would be the best xover frequency for a 2 ways speaker with a 10" woofer ?

It depends on the specifics and on what your priorities are, and there are many different sets of priorities.

I like for the off-axis sound to be similar to the on-axis sound, so I like for the radiation pattern of woofer and horn to be the same in the crossover region, at least in the horizontal plane. And I like to use horns which are "constant directivity", or approximately so. And I do not like diffraction horns because I think they tend to sound harsh at high SPLs.

this two-way solution has several advantages

I think two-way would be much more practical than three-way for what you are trying to do.

The biggest issue is to establish the portion of frequencies to be reproduced by the horn
in PA speakers the woofer does up to even 5kHz
in the speakers above up to 2kHz

and here I'm completely at sea
once the crossover is established then you can select a suitable horn and driver
I really don't know what to do in short

I suggest you learn as much as you can and make all of your major choices simultaneously, taking as much into account as you can. This is because you are designing a system and the various parts of the system affect one another.

For instance, my personal priority being a well-behaved radiation pattern, I would look for woofer-plus-horn/compression driver combinations that allow for pattern-matching in the crossover region. A 10" woofer's radiation pattern width is about 90 degrees in the 1.6 kHz ballpark, which should work well with a 90-degree constant-directivity horn that maintains good output and good pattern control (at least in the horizontal plane) down to 1.6 kHz, plus some overlap for the crossover. Good off-the-shelf 90 degree constant-directivity horns are fairly rare, so maybe go with 80 degrees and plan to cross over around 1.8 kHz, where the woofer's pattern has narrowed a bit more.

With that intro, here is why I say to make all of your major choices simultaneously: Obviously the horn needs to have the characteristics you want; the woofer needs to have high SPL capability and go high enough while still having good bass (and there is a tradeoff between good bass and good top-end extension); the compression driver needs to work well with that horn and be able to go low enough in a demanding ("small disco") application; and you need enough overlap to be able to do a practical crossover. Any one choice that you get wrong can mess up the entire project if sound quality is a high priority.

In my opinion.
 
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No issue at all - any good compression driver will work flawlessly above 1500 Hz, so does many average-size horns. Those drivers and horns are not very expensive.
But anything below 800 Hz demands big and very expensive compression drivers and big and expensive horns.
This is a very important point I would not like big sizes and costs I will focus the 2ways solution then at least as a first experience
Midrange horn may use cone driver and can be build from plywood
you mean that there are off the shelf horns that can work with cone drivers ? could you tell me some brands please ?
a weird old idea was to load a small full range cone driver Avantgard use Horns also for their cone mids but they build them out of plastics i guess
So, it is a no-brainer - crossover frequency for a 2-way loudspeaker should be between 1500 and 2000 Hz, depending on the compression driver.
You can find 5 kHz crossover only in low-quality, cheap PA speakers.
yes the speakers i have seen are very cheap Why they use such a high crossover ? i could always redone the xover and change the tweeter driver with something compatible and better And keep the woofer and the cabinet of course
Decent 2-way PA speakers have crossover frequency around 2000 - 2500 Hz.
First you choose driver and horn, depending on the budget. Then the crossover frequency naturally follows.
thanks a lot again Another weird idea is to cannibalize the amps of some cheap little powered speakers
i have alreay two pairs unused in the garage just ready for some surgery
The two ways are often crossed at 2kHz
The nice thing is that they have balanced connection that i like I have already a balanced preamp that i respect
still what could be the reason of that high crossover point in cheap PA speakers ? i am curious
 
A 3-way approach is typically good, though not necessarily all in one enclosure.
Without being very large, the mid/high frequency range in a speaker like this typically has high sensitivity (gets loud with relatively little power). For the low frequency drivers to match that kind of sensitivity and go very low simultaneously requires a large and possibly complex enclosure.
thank you very much again Yes i have seen some sensitivity graps and the horn tweeters are like 10dB more efficient
i am shocked by the effect of a horn I really wonder why they are not the norm also in the so called high end market I still see little domes used
Looking at the speakers i notice come unbalance in sizes Big woofers and just a 1" tweeter ????
With amplifier power getting cheaper all the time and the availability of high excursion woofers, a more practical approach is to use separate active subwoofers crossed at around 80-100 Hz. This also makes it easy to add more subwoofers until you're happy with the output, lets you distribute the subwoofers for more even response through the room (if that's a priority), etc. If you get a subwoofer or subwoofer amplifier that includes DSP, you can also typically equalize the in-room response, which is also very handy.
thanks again but this complicate the system This will be just a beginning not the end i hope
I am also interested for my home listening I start to love horns I like in general what is efficient I have seen lately 80dB speakers
I have the feeling that some speakers distort much before they start to sing They are like wrong by design
 
you mean that there are off the shelf horns that can work with cone drivers ? could you tell me some brands please ?
There are plastic horns on the market (for example, for 10" midrange: https://ds18.com/collections/horns/products/mid-diffuser-for-extremely-loud-sound-10 ).

You have to build plywood horns by yourself - here is a plan for building popular 12-inch Dynacord F12:
http://hornplans.free.fr/f12cwh.html
https://cdn.korn.eu/pictures/product/400/144824.jpg
On the front there is high frequency horn and driver, behind is 12" midbass.

a weird old idea was to load a small full range cone driver
No!

the speakers i have seen are very cheap Why they use such a high crossover ?
Because there is no low-pass filter for the midbass driver.
 
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There are plastic horns on the market (for example, for 10" midrange: https://ds18.com/collections/horns/products/mid-diffuser-for-extremely-loud-sound-10 ).
Thanks ! actually i was thinking to horns for smaller cones Like 4" max and little domes i mean for not only compression drivers
Acapella and Avantgarde use horns to load conventional drivers i.e. not compression drivers
woofers stay as they are for now Horn loading a woofer is quite uncommon
You have to build plywood horns by yourself - here is a plan for building popular 12-inch Dynacord F12:
http://hornplans.free.fr/f12cwh.html
https://cdn.korn.eu/pictures/product/400/144824.jpg
On the front there is high frequency horn and driver, behind is 12" midbass.
i should ask a carpenter he would charge me easily 1000 usd for the complete work
I cant do this by myself No skills no tools I do not want to end with 9 fingers
plastic ones are fine
Because there is no low-pass filter for the midbass driver.
wow I did not know Now i understand why they can sound rough there is an overlap between the two drivers ? crazy
Very easily fixable Just a coil in series and a cap in parallel No problem Done !
i have a pair of PA speakers on the radar They will be my testing bench soon My only constraint is space Since the last relocation i have filled my garage
 
why they are not the norm
They are physically larger, which is not the trend in most speakers. Good horns and compression drivers tend to cost more than simple direct radiator speakers as well. They can also have different kinds of distortion and coloration than standard cones/domes which can create a less even overall frequency response. If you want the lowest distortion and easiest implementation, a dome tweeter is typically going to win at the lower volume levels of average home audio.

unbalance in sizes Big woofers and just a 1" tweeter
This is mostly due to a basic sound generation issue: each octave lower you go in frequency requires 4x the displacement to achieve the same SPL. A small tweeter can typically keep up with much larger woofers as long as the tweeter cross point is sufficiently high.

I have seen lately 80dB speakers
As in the first point, the trend in speakers is toward small designs that have decent bass extension. This leads to low sensitivity, as summarized by Hoffman's Iron Law:

https://en.wikipedia.org/wiki/Josef_Anton_Hofmann
"Hofmann theorized that when woofers are mounted in speaker enclosures, the designer would have to accept that there are three trade-offs. Hofmann argued that the designer had '...three parameters that cannot all be had at the same time. They are low-bass reproduction, small (enclosure) size, and high (output) sensitivity.' Hofmann stated that designers could pick two of these three parameters, but in doing so, it would compromise the third parameter"

some speakers distort much before they start to sing They are like wrong by design
It depends on what you are designing for. For many users, a small speaker is more important than one that can play cleanly at very high levels. If you want to listen loud, careful speaker selection is important. And if you want loud and low at normal distances, large volume displacement is critical: you just can't get there with a tiny woofer.

there is an overlap between the two drivers ?
If done properly the natural roll-off of the woofer is used as part of the crossover. This is done both in very inexpensive designs and in those that are pursuing minimalist crossover implementations. As with any other design element, it can be done well or poorly.
 
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They are physically larger, which is not the trend in most speakers.
i see But at least an acoustic waveguide I do not know what effect has a wave guide on a tweeter performance
some PA cinema speakers use cone drivers and with waveguides around them like JBL
1731859952962.png

Good horns and compression drivers tend to cost more than simple direct radiator speakers as well.
i was referring to very expensive speakers clearly not made out of cast iron or exotic woods
They can also have different kinds of distortion and coloration than standard cones/domes which can create a less even overall frequency response. If you want the lowest distortion and easiest implementation, a dome tweeter is typically going to win at the lower volume levels of average home audio.
Thank you very much this close the issue I like extremely low THD and noise
This is mostly due to a basic sound generation issue: each octave lower you go in frequency requires 4x the displacement to achieve the same SPL. A small tweeter can typically keep up with much larger woofers as long as the tweeter cross point is sufficiently high.

As in the first point, the trend in speakers is toward small designs that have decent bass extension. This leads to low sensitivity, as summarized by Hoffman's Iron Law:

https://en.wikipedia.org/wiki/Josef_Anton_Hofmann
"Hofmann theorized that when woofers are mounted in speaker enclosures, the designer would have to accept that there are three trade-offs. Hofmann argued that the designer had '...three parameters that cannot all be had at the same time. They are low-bass reproduction, small (enclosure) size, and high (output) sensitivity.' Hofmann stated that designers could pick two of these three parameters, but in doing so, it would compromise the third parameter"

It depends on what you are designing for. For many users, a small speaker is more important than one that can play cleanly at very high levels. If you want to listen loud, careful speaker selection is important. And if you want loud and low at normal distances, large volume displacement is critical: you just can't get there with a tiny woofer.

If done properly the natural roll-off of the woofer is used as part of the crossover. This is done both in very inexpensive designs and in those that are pursuing minimalist crossover implementations. As with any other design element, it can be done well or poorly.
🙂👍
 
what effect has a wave guide on a tweeter performance
It's typically a rise in sensitivity as frequencies decrease and narrowing of dispersion in the lower range. The graphs below do not go to large enough angles to show much of the second effect, but you do see some narrowing in the 2-4 kHz region at 30°.

http://www.zaphaudio.com/hornconversion.html
1731861845725.png

1731861887552.png


A short paper discussing some additional points:
https://amphion.fi/wp-content/uploads/2022/05/Advantage_of_using_waveguides.pdf

very expensive speakers
Cost, complexity, and the intended use case still matter.
I like extremely low THD and noise
Again, this comes down to how each is used. If you are listening at high levels, the horn may have lower distortion at that SPL even though it inherently has higher distortion at lower playback levels than a direct radiator.
 
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