Punisher and X-tro - Xtro flare redevelopement thread

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Xtro flare redevelopement thread

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Forum Name: Punisher and X-tro
Forum Description: Discussion / Questions about the Punisher and X-tro
URL: https://forum.speakerplans.com/forum_posts.asp?TID=98310
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Topic: Xtro flare redevelopement thread

Posted By: gen0me
Subject: Xtro flare redevelopement thread
Date Posted: 15 April 2017 at 1:35pm

So far I have the shape of horn as stl(in the link).

https://drive.google.com/drive/folders/0B5y23T8xURtGNmZwVlRsM3pmeXM?usp=sharing

Still need to work on phase plug.
I need help in measuring the speaker as on the images: Every 3 cm is good enough.

Have fun. Feel free to check for mistakes. So far I know there is missing 1.8cm length in simulation on size of plywood in front of driver.

Replies:

Posted By: gen0me
Date Posted: 21 April 2017 at 9:55pm

Anyone has b&c 8pe21 to show or measure? In England?
Actually it should be enough to measure how far is the dustcap from front.

Posted By: cravings
Date Posted: 22 April 2017 at 12:05am

i have some. i'll check tomorrow if no one else has.

Posted By: toastyghost
Date Posted: 22 April 2017 at 2:34am

What are you trying to achieve with the horn design? The sims you've done show a very wide dispersion and a change of 35 degrees in half an octave lower is quite sudden.

Posted By: gen0me
Date Posted: 22 April 2017 at 3:33am

:) I have no goal tbh. Just something that will fit exactly Xtro, may be more universal.
Arent those frequencies where every horn gets directional?
So is it good approach?

Posted By: toastyghost
Date Posted: 22 April 2017 at 12:33pm

Not a well designed one, no. A good speaker has consistent pattern control to at least 800-1k, ideally lower. Otherwise half your vocal is immediately subject to reflections or comb filtering.

You would likely do better to decide your design goals and build to that. It would also help to have directivity plots of the HF and LF sections to ensure a smooth transition.

I know of one builders' three way horn loaded cabinet that has HF exactly 60 but the mid horn starts at 90 and ends up at 160 by 400hz, and it's horrendous in multiples.

Posted By: gen0me
Date Posted: 24 April 2017 at 11:34pm

Here is the original one from https://freespeakerplans.com/forum/38-hosted-plans/5431-x-tro
I see the problem. Conical horn seems to control dispersion better(smaller difrences in frequency change).

Posted By: gen0me
Date Posted: 14 May 2017 at 1:51pm

Im a little confused. So what directivity should I expect? Like for http://beyma.com/getpdf.php?pid=TD245" rel="nofollow - http://beyma.com/getpdf.php?pid=TD245 . Around 70 x 70 around 2-3khz. For http://www.bcspeakers.com/products/horn/1-0/0/me45" rel="nofollow - http://www.bcspeakers.com/products/horn/1-0/0/me45 55x45 around 2-3khz. Whats the most popular hf horn than?

Posted By: ceharden
Date Posted: 14 May 2017 at 10:01pm

The XT8 is very hot on-axis above 1kHz, most likely due to the directivity at that frequency being determined by the initial expansion from the throat.

The original Xtro flare, being conical is actually much better in that respect.

Posted By: gen0me
Date Posted: 14 May 2017 at 10:42pm

Do you have any directivity characteristics? Basicly any info really appreciated. Im fighting here with abec http://forum.speakerplans.com/abec-problems_topic98514.html
I started even cooling processor with ventilator. Got so hot

Im wondering xt8 was designed by try and makes methods or invented in some software? Or made partly as rough idea in hornresp and than perfected?

Wider openning at the begging may be due to extending top of bandwidth around 2.2k. As I was simulating with hornresp I could go higher with Sentry around 170cm2 than 100cm2

Posted By: Mark James
Date Posted: 23 May 2017 at 6:44pm

so a ce horn type thing [ie conical with the phase plug effectively makeing the first section exponential for loading reasons] might be an idea here then?

-------------
me so horny me love you long throw
horn loaded for her pleasure

Posted By: ceharden
Date Posted: 23 May 2017 at 9:24pm

gen0me wrote:

Do you have any directivity characteristics? Basicly any info really appreciated. Im fighting here with abec http://forum.speakerplans.com/abec-problems_topic98514.html
I started even cooling processor with ventilator. Got so hot

I suspect there was a fair amount of guesswork and no simulation.

I would concentrate on getting the dispersion right, frequency response is easier to fix with EQ...

The original straight Xtro flare, plus phase plug as Markk says would be a reasonable starting point.

When I was thinking about doing something similar, I wanted to try a Quatratic Throat Waveguide:

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.536.5361&rep=rep1&type=pdf" rel="nofollow - http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.536.5361&rep=rep1&type=pdf

Posted By: cravings
Date Posted: 23 May 2017 at 9:30pm

to put a phase plug in the original straight horn.. you'd need to totally change the start of the horn to accomodate the plug, therefore the geometry.. it's a begin again project really isn't it?

Posted By: toastyghost
Date Posted: 23 May 2017 at 11:26pm

ceharden wrote:

I suspect there was a fair amount of guesswork and no simulation.

I would concentrate on getting the dispersion right, frequency response is easier to fix with EQ...

The original straight Xtro flare, plus phase plug as Markk says would be a reasonable starting point.

When I was thinking about doing something similar, I wanted to try a Quatratic Throat Waveguide:

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.536.5361&rep=rep1&type=pdf" rel="nofollow - http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.536.5361&rep=rep1&type=pdf

You can change the response with EQ but only in one position - if your directivity is way off at certain frequencies then you aren't going to fix that with filters, especially if you're not a serious whizz.

Posted By: Teunos
Date Posted: 24 May 2017 at 7:14am

ceharden wrote:

I suspect there was a fair amount of guesswork and no simulation.

I would concentrate on getting the dispersion right, frequency response is easier to fix with EQ...

The original straight Xtro flare, plus phase plug as Markk says would be a reasonable starting point.

When I was thinking about doing something similar, I wanted to try a Quatratic Throat Waveguide:

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.536.5361&rep=rep1&type=pdf" rel="nofollow - http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.536.5361&rep=rep1&type=pdf

Its funny how many (fundamental) mathematical errors are in that paper.
(I did not click on the link but i assume this is the peavey document?)
Also, if you start drawing out the (correct) equations and throw them into a simulator, you will probably find out pretty quickly why it really isnt all that amazing.

-------------
Best regards,
Teun.

Posted By: ceharden
Date Posted: 24 May 2017 at 9:00am

I would imagine a QTW can't be worse than just a straight conical waveguide without a smooth transition at the throat?

I did start doing some experiments a couple of years ago with the fibreglass versions of the Xtro flare. I modified the throat from square to closer to rounded and trying to add Martin Wavefront style 'Phase Balls' although I was only making them from Polystyrene and probably weren't rigid enough. Loaded with a an 18Sound 8M400 it did work fairly well. I can't remember what the high extension was like. I've still got the ones I started modifying if anyone wants to pick up the project because I can't see me doing it any time soon.

Posted By: Mark James
Date Posted: 24 May 2017 at 10:38am

how much?

-------------
me so horny me love you long throw
horn loaded for her pleasure

Posted By: krestudon
Date Posted: 26 May 2017 at 11:42am

Do you still need measurements on a B&C 8pe21?

I'm available.

Posted By: gen0me
Date Posted: 01 June 2017 at 12:11am

Thanks krestudon, I have them already.

What inspires me now is this:
http://www.bluearan.co.uk/index.php?id=SONMR8XT&browsemode=manufacturer
Dont know how much of it is true(even italians dont have that nice dispersion chars). Ofc scale is high to blind eye but it should be doeable anyway!

Here are some of my tries:
https://drive.google.com/drive/folders/0B5y23T8xURtGNmZwVlRsM3pmeXM?usp=sharing
Mostly on the blind shoot. I was trying to do hornresp one(that would guarantee similar power on all the bandwidth) with very fast expanding after throat. Ofc hornresp sim has huge circumference value(from 43cm2 to 161cm2 in 3mm) but to do at lest something similar or go this way. Suprisingly this short phase plug that allows fast expansion after throat dont look so good on Abec sims.

Posted By: Teunos
Date Posted: 01 June 2017 at 6:07am

Normalized directivity plots would be way more useful.

-------------
Best regards,
Teun.

Posted By: gen0me
Date Posted: 01 June 2017 at 7:13pm

Thats for 40V Distance almost 4m. Hmm smt doesnt calculate.

Posted By: Teunos
Date Posted: 01 June 2017 at 8:38pm

Normalized means that everything off axis is eqed such that the on axis frequency response in the directivity plots is constant.
This way, you actually see what the horn geometry itself does to the directivity.
If you have a huge peak on axis, it will also show off axis.
Of course you would want to research the reason for this peak and battle it, but shallow trends still give twisted results.

-------------
Best regards,
Teun.

Posted By: gen0me
Date Posted: 13 June 2017 at 10:42pm

Need to figure out how to do it in abec.
I need some help in interpretation of the resaults. Is it possible that vertical and horizontal angles of horns influence dispersion from around 1.6, 1.8 kHz and lower much more important is mouth shape which works kind of against(verticaly wider, horizontaly narrower)? Top printscreens are horizontal, bottom vertical.

Next one.

Posted By: Teunos
Date Posted: 14 June 2017 at 7:52am

Read up on Huygens theory and imagine how it would affect sound.

If the source is small compared to the wavelength, the source will become omnidirectional. If the source is much larger than the wavelength, it will automatically be directional.

Typically you have 3 regimes that control directivity.

Low frequencies where the wavelength is much lower than the size of the horn in the measurement plane. In this area directivity is primarily controlled by horn size and efficiency/frequency response by expansion profile. Since your horn is wider than it is tall, it will be more directive down low in the horizontal plane than it will be in the vertical plane. This is contradictive to what you want if you for instance want a 60Hx40V horn. Below a certain frequency, the horn will become more directive in the plane with the bigger size, in this case the horizontal plane. This is a phenomenon commonly refered to as pattern flip.
Midband frequencies where the wavelength of the sound is roughly equal to the size of the horn. In this area, both directivity and and frequency response are HEAVILY influenced by horn geometry more than it is influenced by the size. Since the wavelength is roughly equal to the horn dimensions, you can get all sorts of reflections and therefor standing waves inside your horn if the mouth does not perfectly terminate in a smooth transition towards the open space. This is because the sound undergoes a change in acoustic impedance and if this change is abrupt, it will cause the sound to be reflected. Usually in this area is where you see edge effects that cause comb filter like effects in the frequency response, and long, slow decaying trails in a waterfall plot. The effects you see in a directivity graph are what is commonly known as midrange waste-banding.
High frequencies where the wavelength is bigger than the sound. In this region, size does not matter anymore. The primary effects that affect the dispersion is simply the angle of the horn walls, and how well the sound can follow these walls. If you have a horn with a rapid expansion profile, the higher frequencies will ''break'' free from the walls very soon which means that for increasing frequency, the directivity increases and dispersion angles decrease.
To make sure that even the highest of frequencies are ''dispersed'' throughout the intented coverage angle, many horn designs use a diffraction slot. If the width of this slot is small enough compared to the wavelength, the slot will be omnidirectional. If the horn angle after that is for instance 90 degrees, the sound will be dispersed throughtout the full 90 degrees. (again, read up on Huygens). The diffraction slot however is a distortion generating beast since like i said in 2, it offers a HUGE abrupt change in acoustics impedance > reflected sound > standing waves > resonances> high distortion. (This is why i love my JABO KH53 horns on the BMS horns, no diffraction slot. These horns sound leagues better than the JBL 2385A i also sometimes use. (See the topic : http://forum.speakerplans.com/2-tractrix-horn-any-interest_topic97925_page1.html" rel="nofollow - http://forum.speakerplans.com/2-tractrix-horn-any-interest_topic97925_page1.html )

In your horn, which i guess is around 50cm wide, the point where the flip between 1 and 2 occurs is roughly around the 400~500Hz ballpark horizontal and higher for the vertical. This means that you will never, ever with these horn sizes, get a horn that is directive to below this frequency region. This shows in your simulations.

What your simulations also show, is that in this area (500Hz), the directivity decreases, typical midrange waste-banding behavior. I do need to add, that this might be exaggerated a bit since around 700Hz your on-axis sensitivity is higher. What your simulations also show is that this effect is much worse in the vertical plane than in the horizontal plane. This is logical, since your horizontal termination to the open air is WAYYYY more smooth than that for the vertical, which is basically an open ended pipe.

The funniest part of this all to me, is that most people have no idea that these effects exist. If you listen carefully to a sound system, you can spot them though. Especially when you stack multiple horns side by side, things like this can become problematic pretty fast.

It is THE main difference between a professionally engineered cabinet and a home built DIY system. Measuring frequency response never tells you the entire picture, and you have found that out for yourself, kudos!

Maybe this clarifies why i always recommend people, that if you can stick with one speaker per side with a wide coverage angle (they are way easier to design, and the horns are automatically more constant directivity since the transition from 1>2>3 is way more smooth (physics, yeah!!)), than it is something you should always do i.m.o.

Hope you find some helpful point in this post.

-------------
Best regards,
Teun.

Posted By: gen0me
Date Posted: 14 June 2017 at 9:33am

Seems logical concerning wavelengths. What I cant understand is why between 700hz and 1,6k horn plays wider vertically. It should be affected as in point 2. Horn is very slowly expanding vertically and fast horizontally. Why its reversed?

Offtop:
I am always wondering why line arrays have mids horizontal instead of verticall

Posted By: Teunos
Date Posted: 14 June 2017 at 10:42am

You should think about your question again and the points i made in my previous post. The answers are there.

-------------
Best regards,
Teun.

Posted By: toastyghost
Date Posted: 14 June 2017 at 12:56pm

gen0me wrote:

Offtop:
I am always wondering why line arrays have mids horizontal instead of verticall

Er - they have them vertical, you stack the boxes on top of each other

Posted By: gen0me
Date Posted: 26 June 2017 at 3:42pm

So I made bigger mouth. I kept the width but I increased the height. Here it is:

My guess was that transition between 1>2 was vertically around 1,5kHz(on smaller horns) and is around 1,2kHz on bigger one.

Edit:

Teunos wrote:

In your horn, which i guess is around 50cm wide, the point where the flip between 1 and 2 occurs is roughly around the 400~500Hz ballpark horizontal and higher for the vertical.

Is it possible to have such huge difference vertically and horizontally? Its 50cm x 25cm mouth.

Where is this from?

Sometimes it appears way over usefull bandwidth like 4kHz while after 2kHz there is totally nothing.

Posted By: gen0me
Date Posted: 05 July 2017 at 11:41pm

Update:
https://drive.google.com/folderview?id=0B5y23T8xURtGR1hhRGx5UnUyRG8" rel="nofollow - https://drive.google.com/folderview?id=0B5y23T8xURtGR1hhRGx5UnUyRG8
Thought there is a standing wave on 800Hz and there is but changing rear chamber dont eliminate that bump.

Posted By: gen0me
Date Posted: 06 July 2017 at 8:19pm

Teunos there is no option of normalized response in Abec. I can only make measurements at points or arcs. Not the whole sphere.
Here is bonus standing wave in rear chamber:

Does xtro originally has this mountain around 800Hz?

Posted By: gen0me
Date Posted: 09 July 2017 at 2:52pm

7.10 update. https://drive.google.com/folderview?id=0B5y23T8xURtGN3hvcks1WV9pNWc

And here Ive got a winner:

Diffraction slot was a briliant idea.

The bold line(top pattern) is always horizontal.

Posted By: Sapro2
Date Posted: 10 July 2017 at 6:21pm

Teunos wrote:

Read up on Huygens theory and imagine how it would affect sound.

If the source is small compared to the wavelength, the source will become omnidirectional. If the source is much larger than the wavelength, it will automatically be directional.

Typically you have 3 regimes that control directivity.

Low frequencies where the wavelength is much lower than the size of the horn in the measurement plane. In this area directivity is primarily controlled by horn size and efficiency/frequency response by expansion profile. Since your horn is wider than it is tall, it will be more directive down low in the horizontal plane than it will be in the vertical plane. This is contradictive to what you want if you for instance want a 60Hx40V horn. Below a certain frequency, the horn will become more directive in the plane with the bigger size, in this case the horizontal plane. This is a phenomenon commonly refered to as pattern flip.
Midband frequencies where the wavelength of the sound is roughly equal to the size of the horn. In this area, both directivity and and frequency response are HEAVILY influenced by horn geometry more than it is influenced by the size. Since the wavelength is roughly equal to the horn dimensions, you can get all sorts of reflections and therefor standing waves inside your horn if the mouth does not perfectly terminate in a smooth transition towards the open space. This is because the sound undergoes a change in acoustic impedance and if this change is abrupt, it will cause the sound to be reflected. Usually in this area is where you see edge effects that cause comb filter like effects in the frequency response, and long, slow decaying trails in a waterfall plot. The effects you see in a directivity graph are what is commonly known as midrange waste-banding.
High frequencies where the wavelength is bigger than the sound. In this region, size does not matter anymore. The primary effects that affect the dispersion is simply the angle of the horn walls, and how well the sound can follow these walls. If you have a horn with a rapid expansion profile, the higher frequencies will ''break'' free from the walls very soon which means that for increasing frequency, the directivity increases and dispersion angles decrease.
To make sure that even the highest of frequencies are ''dispersed'' throughout the intented coverage angle, many horn designs use a diffraction slot. If the width of this slot is small enough compared to the wavelength, the slot will be omnidirectional. If the horn angle after that is for instance 90 degrees, the sound will be dispersed throughtout the full 90 degrees. (again, read up on Huygens). The diffraction slot however is a distortion generating beast since like i said in 2, it offers a HUGE abrupt change in acoustics impedance > reflected sound > standing waves > resonances> high distortion. (This is why i love my JABO KH53 horns on the BMS horns, no diffraction slot. These horns sound leagues better than the JBL 2385A i also sometimes use. (See the topic : http://forum.speakerplans.com/2-tractrix-horn-any-interest_topic97925_page1.html" rel="nofollow - http://forum.speakerplans.com/2-tractrix-horn-any-interest_topic97925_page1.html )

Sorry to hijack but Teunos that was a brilliant post. Thankyou

-------------
Splat Soundsystem
Baby Sham pram Soundsystem
Sapro - SoundCloud
https://soundcloud.com/sapro
DJ Sapro. West country free party DJ and Producer.

Posted By: gen0me
Date Posted: 27 July 2017 at 9:26pm

I was wrong. The 800hz mountain is not from rear ch standing waves. It seems to be tendency of horn for higher efficiency. I did similar things to those preventing midband wasting(bigger smoother mouth) and all efficiency of top bandwidth rose to level similar to this 800hz.
Here are the two horns:
7,10,16,2(little phase plug update) fits in xtro.

7,10,24 bigger one(higher)

7,10,16,2:

7,10,24:

7,10,16,2:

7,10,24:

7,10,16,2:

7,10,24:

Posted By: Teunos
Date Posted: 28 July 2017 at 12:28am

Keep on exploring good sir

-------------
Best regards,
Teun.

Posted By: gen0me
Date Posted: 18 August 2017 at 3:58am

Teunos wrote:

The diffraction slot however is a (...)beast

Thats why 7,10,24 plays

that high.

I guess slot and outside are out of phase.
It cant be the slot itself. Wavelength there has ~15cm.

Posted By: doller
Date Posted: 18 August 2017 at 1:36pm

fantastic thread, Thanks guys.

Posted By: gen0me
Date Posted: 21 August 2017 at 1:33am

Came to mind previous phase bungs.
I have no idea why some frequencies are played one side of phase plug and a bit higher only another.

Here is one more good horn. Reasonable dispersion up to 2.6kHz.
7.10.33.5

I was comparing different horns like Function 1 Resolution or Martin Audio H3. H3 has wide dispersion and plays up to 2k only. All Resolution's have very narrow dispersion and play really high.
Like:
445hz - 5k77Hz >>> 25h x 20v
445hz - 5k77Hz >>> 50h x 25v
Maybe its impossible with wide dispersion to go that high.

Posted By: toastyghost
Date Posted: 21 August 2017 at 2:28am

The F1 horns actually get quite beamy at the upper register, you can see it on the isobars in the production partner review of the EVO.

Posted By: gen0me
Date Posted: 26 October 2017 at 7:15pm

Here is narrow dispersion longer one: 50cm wide, 40 high, 48.9 long(including plywood) to the driver.

https://s1.postimg.org/5bjrsewb67/7_10_33_5_7final.jpg" rel="nofollow - https://s1.postimg.org/5bjrsewb67/7_10_33_5_7final.jpg

https://s1.postimg.org/5q2yxg06sf/7_10_33_5_7final_pic.jpg" rel="nofollow - https://s1.postimg.org/5q2yxg06sf/7_10_33_5_7final_pic.jpg

https://s1.postimg.org/4g01r4rmzj/7_10_33_5_7final_off_axis_response.jpg" rel="nofollow - https://s1.postimg.org/4g01r4rmzj/7_10_33_5_7final_off_axis_response.jpg

https://s1.postimg.org/2ojuae7pqn/7_10_33_5_7final_directivity.jpg" rel="nofollow - https://s1.postimg.org/2ojuae7pqn/7_10_33_5_7final_directivity.jpg

45H x 30V on top of the bandwidth.

Posted By: gen0me
Date Posted: 11 January 2018 at 5:46pm

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