To summarize, your "small" horn example isn't that small, not nearly as small as my examples when you consider the low knee frequency and size difference ratio between small and full size horns compared.
Also, you used a pure EXP flare which is going to be almost impossible to fold efficiently into a rectangular shaped box.
Despite all that, your small horn still doesn't stack up well to a full size horn as I have shown, even though the full size horn is only 2.5x larger than your small horn example.
Your small horn example fails at every single one of the four main large horn metric characteristics.
I realize you are new to the forum, in fact your only 2 posts here are the 2 posts in this thread. Being new is not an excuse for ignorance when you join a forum for the single purpose of arguing with someone.
If you came to the forum showing your design and asking questions about why your design seemed to break the rules (the four main characteristics of full size horns that small horns don't have) then we could have had a civil conversation. But joining the forum just to tell me I'm wrong and my designs are bad is not a good way to start, especially when it's so easy to prove that you are completely wrong in every single thing you've posted so far in your short history here.
Doing this during the holidays is especially irritating, since I've now had to spend time defending myself instead of spending that time with family.
It seems that you have some of the basics down at this point but just a word of caution for you - coming to this place and challenging the senior members is going to go very badly for you unless you are 100 percent sure of yourself. And as I've just shown very clearly your technical knowledge is a bit shaky, your example was unfair in the extreme (compared to the size ratios I was comparing) and it's led to some very wrong conclusions and assertions on your part.
Also, you used a pure EXP flare which is going to be almost impossible to fold efficiently into a rectangular shaped box.
Despite all that, your small horn still doesn't stack up well to a full size horn as I have shown, even though the full size horn is only 2.5x larger than your small horn example.
Your small horn example fails at every single one of the four main large horn metric characteristics.
I realize you are new to the forum, in fact your only 2 posts here are the 2 posts in this thread. Being new is not an excuse for ignorance when you join a forum for the single purpose of arguing with someone.
If you came to the forum showing your design and asking questions about why your design seemed to break the rules (the four main characteristics of full size horns that small horns don't have) then we could have had a civil conversation. But joining the forum just to tell me I'm wrong and my designs are bad is not a good way to start, especially when it's so easy to prove that you are completely wrong in every single thing you've posted so far in your short history here.
Doing this during the holidays is especially irritating, since I've now had to spend time defending myself instead of spending that time with family.
It seems that you have some of the basics down at this point but just a word of caution for you - coming to this place and challenging the senior members is going to go very badly for you unless you are 100 percent sure of yourself. And as I've just shown very clearly your technical knowledge is a bit shaky, your example was unfair in the extreme (compared to the size ratios I was comparing) and it's led to some very wrong conclusions and assertions on your part.
Now just in case it's not abundantly clear I will make is so in plain text without pictures.
If the driver and low knee are held constant and the variable is size ratio difference between the small horn and the full size horn, small size ratio differences will mean small performance differences when the two are compared. And large size ratio differences will mean large performance differences when the two are compared.
This recently presented "small" horn performed better in the 4 described metrics than any of my examples in this thread simply because it wasn't very small compared to a full size horn using the same driver and low knee.
His size ratio difference between the small horn and a full size horn for the same driver and low knee was only 2.5:1 when compared to my examples at 6.6:1 and 12.2:1. My examples are MASSIVELY undersized, his wasn't. This is the main reason that his performed better than mine in all aspects.
But as expected, even his ironically large "small" horn example still doesn't hold a candle to the performance of a full size horn using the same driver and low knee. Not in ANY performance metric, and certainly not in the four main metrics I've been focusing on since the first post.
If the driver and low knee are held constant and the variable is size ratio difference between the small horn and the full size horn, small size ratio differences will mean small performance differences when the two are compared. And large size ratio differences will mean large performance differences when the two are compared.
This recently presented "small" horn performed better in the 4 described metrics than any of my examples in this thread simply because it wasn't very small compared to a full size horn using the same driver and low knee.
His size ratio difference between the small horn and a full size horn for the same driver and low knee was only 2.5:1 when compared to my examples at 6.6:1 and 12.2:1. My examples are MASSIVELY undersized, his wasn't. This is the main reason that his performed better than mine in all aspects.
But as expected, even his ironically large "small" horn example still doesn't hold a candle to the performance of a full size horn using the same driver and low knee. Not in ANY performance metric, and certainly not in the four main metrics I've been focusing on since the first post.
Greetings. I'm trying to get a handle on things here, maybe you could outline you application as different horns suit different purposes. What do you see as a good set of attributes for a horn in this range? What is the significance of things like group delay and such, and what do they say about a horn?
I have no idea what type of answer you are looking for here. As I mentioned a few posts back there is no right or wrong, just better or worse when compared to a specific set of goals.
The purpose of this thread was to very specifically look at full size vs undersized horns to investigate whether or not the undersized horns had the characteristics that are commonly attributed to horn designs.
If you want a discussion about what makes a good horn for any specific goal set we can do that but this thread is not the right place for that. The furthest I'm going to bite into that topic in this thread is to say that it's awful hard to beat a full size horn in any performance metric. But since small enclosure size is often the number 1 predominant goal compromises must be made. I'm not going to discuss those compromises or their impact here anymore than I already have with all the different example comparisons. But if you want to start a new thread for that topic you can go ahead and I'll be along to comment if you want my input.
The purpose of this thread was to very specifically look at full size vs undersized horns to investigate whether or not the undersized horns had the characteristics that are commonly attributed to horn designs.
If you want a discussion about what makes a good horn for any specific goal set we can do that but this thread is not the right place for that. The furthest I'm going to bite into that topic in this thread is to say that it's awful hard to beat a full size horn in any performance metric. But since small enclosure size is often the number 1 predominant goal compromises must be made. I'm not going to discuss those compromises or their impact here anymore than I already have with all the different example comparisons. But if you want to start a new thread for that topic you can go ahead and I'll be along to comment if you want my input.
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Good horns, bad verdicts.
You are arguing about the scale.
Maybe this 550dm3 tapped horn will change your mind. Small bandwitch high efficiency
https://postimg.org/image/n2ylq43pd/
Speakerplans.com
:]
Practicality is that those normal size horns make yours true horns in 3's or 4's and you dont need fork lift truck with long forks on it to move them.
Here are same horn Front Loaded 470dm3
1Pc
https://postimg.org/image/7pace1d2h
4Pc
https://postimg.org/image/tpqounvqh/
You are arguing about the scale.
Maybe this 550dm3 tapped horn will change your mind. Small bandwitch high efficiency
https://postimg.org/image/n2ylq43pd/
An externally hosted image should be here but it was not working when we last tested it.
It has been done before, it can be done anytime.
Speakerplans.com
:]
Practicality is that those normal size horns make yours true horns in 3's or 4's and you dont need fork lift truck with long forks on it to move them.
Here are same horn Front Loaded 470dm3
1Pc
https://postimg.org/image/7pace1d2h
An externally hosted image should be here but it was not working when we last tested it.
4Pc
https://postimg.org/image/tpqounvqh/
An externally hosted image should be here but it was not working when we last tested it.
What goes behind this? Ofc depends of kind of music material but.. Arent usually possibilities of LF driver in FL horn dictaded by excursion limit on lowest low? As driver cone excursion depends on voltage not current the difference is left on amplifier side.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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If you don't see why this won't change my mind you are not paying attention to what I've said. This appears to have a low knee even higher than your last example, maybe 60 hz or so but it's hard to tell from a thumbnail size picture.
It looks like you are struggling to understand that you can ONLY get high efficiency if the enclosure is relatively large compared to the frequency of interest. In other words, the only reason this new example has high efficiency is because it's only about 1/5 smaller than a full size horn for it's low knee frequency.
A full size horn for a 60 hz flare and the driver you used last time is only 630 liters. Your design is 550 liters, which is almost full size and it doesn't look good compared to a full size horn designed by Hornresp (Leach's math).
An externally hosted image should be here but it was not working when we last tested it.
That link goes to a page of links, not sure what you want me to look at.
The reality of a pure EXP flare is that it flares out very quickly at the mouth. This can be a pain to deal with.
Here's you first horn design laid out on graph paper (that I made but it's to scale). Assuming your horn has an internal width of 45 cm (just big enough to fit the driver in) this is the shape of your flare. The first 50 cm of your horn is not shown (about 20 cm of the EXP segment not shown and the 28 cm CON segment isn't shown).
An externally hosted image should be here but it was not working when we last tested it.
It would be quite difficult to fold this flare shape into an efficient square or rectangle shape. Usually the rear chamber helps to make things fit because it's shape is flexible (whatever shape you want) but in this case you 30 liter rear chamber is very small, about the size of the red square on the graph.
You could make the enclosure width deeper than 45 cm and that would change the shape of the flare on the graph but you quickly get into very high aspect ratios at the throat (very narrow throat) if you do that.
If you think you can fold this thing go ahead and show the fold.
This is true of every subwoofer. Stack a few of them and you get better performance. What's the point?
First you have to find an amplifier that can do 113.14 volts that has a stiff enough power supply to keep that voltage steady for at least a few seconds. This is not going to be a cheap amp. I don't think any of the cheaper Behringer models will do it, not even the Inuke 6000 (but I'm not 100 percent sure on that).
Next the driver has to take all that power and hopefully do so gracefully without a lot of power compression and ideally with no smoke. If you feed that driver 113.14 volts it's going to eat up a lot of power which is not so good for the performance from the thermal perspective.
Here's frequency response and driver power for your design with (bottom row) and without (top row) low and high pass filters. 50 hz 4th order highpass and 80 hz 4th order lowpass IIRC.
While the driver is consuming very little power in the filtered example, if your music contains a steady consistent low crest factor 58 hz note the driver is going heat up quickly and maybe even fail if you play it at 113.14 volts.
This is why all aspects of power (voltage, current, watts) are important. You need to choose an amp with high enough voltage that can play sustained notes and you need to make sure the driver doesn't get too warm.
An externally hosted image should be here but it was not working when we last tested it.
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Also I need to mention that this is the subwoofer forum. The designs that you are showing have a low knee in the 50 - 60 hz range. That's not really a subwoofer, in other forums it would be called a midbass module.
If you started designing stuff with a low knee around 20 or 30 hz and keep the 400 - 500 liter enclosure limit you will find out really fast you can't get high efficiency, impedance matching, pattern control or reduced pressures on the cone.
You have been showing designs with really high tuning and really large boxes in relation to the low knee frequency. None of your designs are very undersized at all, in fact the latest one is almost full size. This is why you are failing to grasp these points.
If you started designing stuff with a low knee around 20 or 30 hz and keep the 400 - 500 liter enclosure limit you will find out really fast you can't get high efficiency, impedance matching, pattern control or reduced pressures on the cone.
You have been showing designs with really high tuning and really large boxes in relation to the low knee frequency. None of your designs are very undersized at all, in fact the latest one is almost full size. This is why you are failing to grasp these points.
Yes the same as you are trying to push that smaller horns arent true, but this has been proven to be false. They are in groups...
in the other hand this wasnt. Technically cant be with hornresp.
You are arguing about the scale of your "true horn" parameters.
It was never meant to be folded! Same as your 5000dm3 horn! So where is your point? Unbendeable?
In your face!
https://s28.postimg.org/ppaeesfy3/distances.png
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https://s28.postimg.org/68pos9ku3/overwiew.png
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https://s28.postimg.org/slxff2lrv/overwiew2.png
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https://s28.postimg.org/glbzeced7/overwiew3.png
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https://s28.postimg.org/ut1o2zr23/surfaces.png
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If you are worried about rear chamber size putting one more desk of plywood wont hurt you.. Or increasing little chamber wont hurt the sound.
That it is true for your "true horns". Even with your list of parameters our normal horns in 3s or 4s are behaving exactly like!
And here is the trick:
When you have 1 amp dedicated for 1 box and you take on party 1 box it is naturally dangerous. But noone builds one horn to take it on play. So obviously has also more powerfull amplifier where powering from it one box isnt a problem. When you use multiple boxes there is again effect as "true horn":
https://s24.postimg.org/n8nl29i2t/3_spl_efi_FL_1pc_470dm3.png
[https://s24.postimg.org/n8nl29i2t/3_spl_efi_FL_1pc_470dm3.png]
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[/url]
https://s24.postimg.org/4drubui11/3_imp_2pc_470dm3.png
[https://s24.postimg.org/4drubui11/3_imp_2pc_470dm3.png]
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[/url]
https://s24.postimg.org/femzgva9x/3_imp_4pc_470dm3.png
[https://s24.postimg.org/femzgva9x/3_imp_4pc_470dm3.png]
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[/url]
So where is the problem?
This is the problem. I am saying that undersized horns do not have the characteristics of a full size horn whose size is dictated by horn theory and Leach's math.
YOU are arguing that very large (very nearly full size) horns and/or stacks of horns that are as big as a full size horn perform almost as well as a full size horn. This should be obvious.
What you don't seem to understand is that small horns do not perform the same as big horns.
Your example in post 27 was 550 liters with a low knee of around 60 hz. A full size horn for that low knee is 630 liters, as I showed. Your design was not undersized, it was very nearly full size.
And stacking subs doesn't change anything. If you use one small horn it will not perform like a full size horn. But if you use a big stack of them that are equal in size to a full size horn then they will perform like a full size horn. This should be obvious.
I've proven all this a few times already, even using your own design examples to illustrate that small horns don't perform like full size horns. All you've done is shown VERY large horn designs and horn stacks because there's no other way to get the performance of a full size horn.
I mean seriously, come on man. Your last thumbnail shows a stack of four subs. Remember, this design was only 2.5x smaller than a full size horn. So your 4 subs stacked example is actually WAY bigger than a full size horn. OBVIOUSLY it performs very well, this is kind of the whole point. A stack of horns that is larger than a full size horn is not undersized. I can't understand how we are failing to communicate on this point.
And I'd like to see that fold picture with some dimensions on it so I can verify that it's even remotely close to the Hornresp horn flare data.
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Good stuff JAG, i'm with you on this latest discussion. However, it's not that black and white as you write it down. It's more a matter of the amount of undersizing... A way way undersized horn won't have the fun characteristics. A slightly undersized horn will have these characteriscs. But not as much as a full sized horn.
Also, this doesn't mean that there is no place in this world for undersized horns, stack 'm and they combine into a full-size horn (as you know).
Also, this doesn't mean that there is no place in this world for undersized horns, stack 'm and they combine into a full-size horn (as you know).
Between the centres of geometry 8000cm3 surface(exit) and 3000cm3 is 725mm.
Surfaces sizes are in previous post photo.
https://s30.postimg.org/9b41gn4dt/distances2.jpg
Surfaces sizes are in previous post photo.
https://s30.postimg.org/9b41gn4dt/distances2.jpg
An externally hosted image should be here but it was not working when we last tested it.
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I guess I'm sorry that I wasn't more clear about this then. I had thought all this was extremely clear but I guess not. Of course it's not black or white, nothing ever is. Extremely undersized horns won't work the same as full size horns whereas almost full size horns (or big stacks of horns equal in size to a full size horn) will work similar to a full size horn.
Most of the bass horns in the world are very undersized and are used just fine without stacking. So I agree, there is a place for undersized horns.
My current sub is a small tapped horn, maybe 60 liters or so and hits 23 hz with authority. It is massively undersized compared to a full size horn for it's low knee frequency and it still works very well. BUT it doesn't have high efficiency across the whole pass band, it doesn't have any pattern control, it is not an effective impedance transformer coupling the driver to the air load and it does not reduce pressures on the cone.
That is not an accurate fold.
I don't care about surface sizes. I want a dimensioned drawing with the measurements at all points of interest marked. I can't even see what your interior cab width is in these pictures.
What I can guarantee is that this fold is not even remotely similar to the Hornresp design. If you look at this picture (which is to scale) you can clearly see that the rear chamber is tiny in relation to the last 75 cm of the horn flare. But in your fold picture the rear chamber is about a full 1/3 of the size of this same segment (the last 75 cm of the horn flare).
An externally hosted image should be here but it was not working when we last tested it.
I'm not sure if your flare is folded properly or even remotely accurately, it's impossible to tell without a dimensioned drawing. But it is very clear that the rear chamber is WAY to big in relation to the last segment of the flare.
You specifically said earlier that you could increase the rear chamber size and it wouldn't affect the design much. Maybe that's what you did in this fold job. Regardless, increasing the rear chamber size does have an effect AND adding volume to the rear chamber just to make the box a rectangular shape is not an efficient fold as it obviously makes the entire enclosure larger.
This is what I said in the first place - it's nearly impossible to efficiently fold this type of flare into a rectangle.
At every step you've actually proven my points for me (which means your assertions have all been wrong) but framed it in a very disrespectful way.
You only have 8 posts at diyaudio, you have used those to claim I've made all kinds of mistakes and that my analysis of full size vs undersized horns is wrong. And you've done it in a very confrontational manner. Yet you've been wrong about everything you've said so far and have shown a horn fold that isn't accurate either.
You are wasting my time.
Here's another way to look at the validity of your fold.
Remember, this is axisymmetric, so the wider stuff (like the mouth) has exponentially more cross sectional area than the smaller stuff (like the rear chamber). Still you can see that the rear chamber is TINY compared to the last 75 cm of the horn.
The whole horn is 599 liters. The rear chamber is 30 liters. Look at the fold pictures you've presented and tell me they are showing an accurate fold. You don't even need a dimensioned drawing to tell that your fold is not even close.
An externally hosted image should be here but it was not working when we last tested it.
Remember, this is axisymmetric, so the wider stuff (like the mouth) has exponentially more cross sectional area than the smaller stuff (like the rear chamber). Still you can see that the rear chamber is TINY compared to the last 75 cm of the horn.
The whole horn is 599 liters. The rear chamber is 30 liters. Look at the fold pictures you've presented and tell me they are showing an accurate fold. You don't even need a dimensioned drawing to tell that your fold is not even close.
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