Wood mid high horn plan

[audiophile.1963]

Hello,
someone can provide me with the building plans for wooden trumpets, like Fostex, for medium high? The building is not a problem, but I did't find plan of Fostex horns on the network. I will use with the JBL 2425j drivers without the tweeter.
Thanks
Giuseppe

[Earl K]

Please visit Yuichis excellent WebSite ( for some DIY inspiration & to also obtain other horn plans ) .

http://www.geocities.jp/arai401204/Top_Page/E-170-1-web.gif (http://www.geocities.jp/arai401204/) http://www.geocities.jp/arai401204/Horn/A480FL/A480FL0016.gif (http://www.geocities.jp/arai401204/Drawings/A480/A-480FL_Dwg.pdf)

<> :)

[richluvsound]

Personally , I wouldn't waste my time building a horn like that for a 1" driver !

[hjames]

Personally , I wouldn't waste my time building a horn like that for a 1" driver !
So you get it for a 2 inch driver and use the JBL adapters to run it with a 1 inch driver ...
Once you get a sense for it, you're encouraged to do the right thing and get the bigger better drivers and ... you already have the good horn for it!

For some of us, its not a bad thing, upgrading in affordable stages ...
We just have to plan it, good and proper ...

[pos]

By the way Heater, you still have Truextent Be diaphragms left on your upgrade list! ;)

[hjames]

By the way Heather, you still have Truextent Be diaphragms left on your upgrade list! ;)
Exactly! ... I'm guessing it will be on the list for quite a while - :D
I suspect buying the PASS Labs XVR crossover and matching amps will happen much sooner! ;)

[Lee in Montreal]

I will use with the JBL 2425j drivers without the tweeter.
Thanks

Carefully choose your horn as very few will go up to 20Khz and can be used in a two-way system.

[MartinV56]

Sorry, Off Topic

[audiophile.1963]

Why 2in? I see that the A-480 1in / Hyperbolic is good for JBL-2425 or TAD-2001 with a frequency range 1200Hz to 20KHz...
Giuseppe

[pos]

Because 1" are for Sissies
http://www.jblpro.com/catalog/support/getfile.aspx?docid=295&doctype=3

[Mr. Widget]

Why 2in? Because those of us fortunate enough to have heard systems with 4" diaphragms and 1.5" or 2" throats have heard the difference. In this case bigger is better.


I see that the A-480 1in / Hyperbolic is good for JBL-2425 or TAD-2001 with a frequency range 1200Hz to 20KHz...Don't believe everything you read, or every graph you see.


Widget

[yggdrasil]

Do you already have the 2425?

Building the larger Yuichi horns to use with a 1" all the way up is probably not a good solution. I predict that the adapter together with the larger throat will ensure the need of massive eq above 10K.

Beware that it is very difficult to achieve HF extension to 20Khz, so any irregularities in the throat end will effect the result.

I.e - be prepared for HF cutoff below 20KHz. You need a measurement mic.

Johnny

[audiophile.1963]

Do you already have the 2425?

Building the larger Yuichi horns to use with a 1" all the way up is probably not a good solution. I predict that the adapter together with the larger throat will ensure the need of massive eq above 10K.

Beware that it is very difficult to achieve HF extension to 20Khz, so any irregularities in the throat end will effect the result.

I.e - be prepared for HF cutoff below 20KHz. You need a measurement mic.

Johnny

Thanks for your reply Johnny,
I have not the JBL 2425j this is my intention. I'm restoring an old pair of JBL 4560 cabinets: I have two JBL 2225h woofers and I would like to built a pair of wood horns for mid high but with JBL driver. I don't want to place the horn on the top of the cabinet but inside of the cabinet as the original version. The space is 14 cm so I can not use a horn too high. if you have a similar horn profile please send it to me.
Thanks
Giuseppe

[yggdrasil]

If you wish to stick with the 1" driver I would consider at least 3 different horns:
- Yuichi 480
- http://www.audioheritage.org/vbulletin/showthread.php?8363-New-project-preparation
- and last a Smith: http://www.audioheritage.org/vbulletin/showthread.php?5454-1200Hz-Smith-horns-for-1-quot-driver

At the moment I am using the small Smith horn in one of my systems all the way up. One of the horns rolls off around 15K and the other one around 16K.

The easiest build is the Smith. Since you are not afraid of the building challenge I urge you to build at least a couple of alternatives and report your experiences back here.

IME there are quite different HF response with different materials/finishes. So a mockup in MDF/chipboard usually won't give you the best HF response. You need to either apply a good finish or use solid wood, oiled or varnished.

Johnny

[Earl K]

Some More Encouragement ;

- Here's a pic from a quite ancient thread where Kelly ( luxmanluver ), built his own wooden knock-off ( mdf maybe ??? ) of the JBL 2345 horn .
- The pic is from here ! (http://www.audioheritage.org/vbulletin/showthread.php?3560-3-Way-Project&p=32666&highlight=#post32666)


Hey Earl
The horn in the 4 Pi's that I built was the Eminence H290, a cool looking horn and compact but certainly not to my tastes. It might be better in wood but that's a lot of work to find out. The horn I ended up building wasn't anything special. Just a plain old 2345 JBL cast aluminum ( a real POS casting job if you ask me....lol ) that I had literally holding the garage door open on windy days.

,,,,,snip,,,,,

But all in all I'm just plain out amazed at how this wood horn has smoothed out the sound. CD's that were previously "unlistenable" ie R. L. Burnside "Come On In" certain comes to mind. Great CD, TERRIBLE recording job. I think they used one mike in a bathroom or something...lol .


http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=3745&stc=1&d=1098558437



Pi speakers
"(I guess you gave up on making those Pi boxes sound acceptable - yes / no ? )"


Thought I better answer that one right away. I always liked some aspects of the Pi's. The model I built wasn't to my taste and in retrospect I know why. It was the Eminence horn/driver combo. Even the JBL 2421 didn't sound anywhere near as good on the plastic horn as it does on my homemade jobbies. Also I'm currently using Waynes recomendation of 4 cu' for the 2235H instead of JBL's 5 cu' which I tried in the previous incarnation of this design and was very unhappy with. The 4cu' cabinets have much tighter sounding bass IMO.
Kelly



FYI ; JBL 2345 horns come up for sale once in a while on eBay .

If they interest you / perhaps buy them / & then clone them in wood, the"Kelly Way" ( ie; he worked with having an example "in hand" / rather than from "blue-prints or plans" ) .

<> EarlK :p

[audiophile.1963]

If you wish to stick with the 1" driver I would consider at least 3 different horns:
- Yuichi 480
- http://www.audioheritage.org/vbulletin/showthread.php?8363-New-project-preparation
- and last a Smith: http://www.audioheritage.org/vbulletin/showthread.php?5454-1200Hz-Smith-horns-for-1-quot-driver

At the moment I am using the small Smith horn in one of my systems all the way up. One of the horns rolls off around 15K and the other one around 16K.

The easiest build is the Smith. Since you are not afraid of the building challenge I urge you to build at least a couple of alternatives and report your experiences back here.

IME there are quite different HF response with different materials/finishes. So a mockup in MDF/chipboard usually won't give you the best HF response. You need to either apply a good finish or use solid wood, oiled or varnished.

Johnny

Hi Johnny
My choice is for Yuichi 480, the building is not a problem because my woodworker has a pantograph. I fear for final result: I want to be shure that sonically It will be good with JBL 2225h & 2425j.
Let me know,
thank you very much
Giuseppe

[audiophile.1963]

Hi Johnny
My choice is for Yuichi 480, the building is not a problem because my woodworker has a pantograph. I fear for final result: I want to be shure that sonically It will be good with JBL 2225h & 2425j.
Let me know,
thank you very much
Giuseppe

...I have only a final question. Choicing Yuichi 480 can I cut directy right and left corner of the horn? If yes, how much should be the degree of the horn corner? Please let me know it is very important for me.
Regards
Giuseppe

[yggdrasil]

...I have only a final question. Choicing Yuichi 480 can I cut directy right and left corner of the horn? If yes, how much should be the degree of the horn corner?
I'm not sure I understand the question. Try to rephrase it, or show us on a drawing.

Johnny

[reVintage]

Hey Audiophile,
If you are going to use this in home system you shouldn´t count on a XO-frequency higher than 4-500Hz from the 4560/2225. So you will need a horn and driver that does this. 2"?

[audiophile.1963]

I'm not sure I understand the question. Try to rephrase it, or show us on a drawing.

Johnny

This is my idea, like wood horn Fostex. The cut frequency will be around 800/1200Hz
Giuseppe

[yggdrasil]

Cutting straight along the red lines will change the horn. I would advice against it.

[audiophile.1963]

Cutting straight along the red lines will change the horn. I would advice against it.

OK Thanks, I will respect the original plan
Giuseppe

[audiophile.1963]

... I forgot... where I can find an adapter to connect the driver to the horn? In the original plan It should be in wood but for me Is diffucult to build. I have seen the adapter of old wood horn Fostex but I don't know where to find these metallic adapter!
Thanks for every help
Giuseppe

[reVintage]

A 480Hz(like Yuichi flare) exponential adapter should be 1,4cm long. If the horn for example is Hypex=0,6, it should be 2,1cm. If making it that thick wood should be no problem.

What is recommended adapter thickness? THose I´ve seen seems shorter.

Still if you build that nice horn, what will you fill the gap between 4560/2225 and the horn with?

[audiophile.1963]

A 480Hz(like Yuichi flare) exponential adapter should be 1,4cm long. If the horn for example is Hypex=0,6, it should be 2,1cm. If making it that thick wood should be no problem.

What is recommended adapter thickness? THose I´ve seen seems shorter.

Still if you build that nice horn, what will you fill the gap between 4560/2225 and the horn with?

My intention is to do a cut crossover frequency at 1200hz, I have a friend with instruments for calculating this. Probably we will modify the volume of the box, I want measure the sound before to finish to restore the boxes so I will be shure of the result.
About the adapter I will try to built by myself.
Giuseppe