System Based Around JBL H9800 Horn

Hi all!


My good friend Richard gave me his amazing casts of the JBL H9800 horns. They are pretty gorgeous and I have only tinkered with them so far seeing how horn loading works.


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The new year is coming and I want to upgrade/design a new system utilizing this horn as it isn't an item I would normally have access to, so my plan has a couple of options in my eyes and I wonder if you guys could give your thoughts, please?


Atm my system is an MTM comprised of CAT378 and two FaitalPro 3FE25 and an SB Acoustics SB23 8" subwoofer each side - sealed. I drive this with two Parasound Zamps anda Behringer iNuke for the sub. I use a MiniDSP 8x8 for all crossovers etc. Here it is as it stands:


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Space and budget is at a premium.


Proposal 1 (cheapest/best WAF):

- H9800 Horn with suitable compression driver - can I get close to 20k??
- 1x Faital Pro 8PR200
- Keep the SB subwoofers as stands

Using the H9800 vertically is also an option!

Stack as shown in mock up:


804016d1577017947-system-based-jbl-h9800-horn-20191222_115045-jpg





Proposal 2 (more expensive/less WAF)

- H9800 Horn with suitable compression driver - can I get close to 20k?
- 2x Faital Pro 8PR200 in a vertical 2.5 config. Design an MLTL that will go to 40hz-ish. Specs say the double xmax will accomodate this
- Scrap the SB subs

Build 80cm floorstanders for the woofers and mount the horn on top.



As far as compression drivers are concerned I have been looking at JBL 2450J. The snout will have to be removed for these drivers to fit the H9800. These drivers will also give me the opportunity to later upgrade to the beryllium diaphragms should someone die and leave me lots of money.

The 2450J seem to tail off towards 20k but I wonder with judicious use of EQ will make them acceptable and have a decent dispersion characteristics?



Are there any other compression drivers that might fit the bill? Budget is about £200 per CD.

I don't really want to add a supertweeter but if needs be...



Am I on the right track here? My wife will simply not tolerate a 12" woofer and cabinet let alone a 15" so smaller woofers are a must.

Any advice welcome! :)
 

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This JBL SYNTHESIS 800 looks like a good solution in form factor. It has the right dimensions:

JBL Synthesis 800 Array Stand Mount Loudspeaker - Reference AV


Also, if anyone can suggest better/more cost effective woofers for either proposal I am all ears. The FaitalPro 8" are cheaper than anywhere outside of europe and I like the brand but I am not set but COMPACT is the MO.


This is the listening environment and distance from speakers to listening position is just under 2 metres.


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Honestly, that is a lot of horn meant to cross what, 750hz ?
And you'd need a big compression driver too.

That big horn is meant to go low, and no sense going that low with drivers as small as 8" and 2khz
That's why everyone recommend 15's, as would I.

Shallower horns sound better than deep horns at high frequencies.
Think nice rounded genelec horn loaded domes.
I bet past 2khz the tweets you have would have better detail.
Or put some felt around those horn dome tweets you already have.

Nice tweet, i had the cat378.
My only complaint is the dispersion, narrows the higher up you go.
Conical rounded short horn.

I enjoyed the cat308 (basically same but no horn).
Perhaps a non ferrofluid would have more detail.
But morels seem to have the fluid.

And happy wife, happy life.
I get it.
And space is a premium over there.

But it took me a while to play with all this stuff.
It is all trade-offs.
Play if you want !!!
I've done stuff and then went, ah, that's why they said not to do that.

Your ears, your money, your room, etc !!!!!!!
 
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Honestly, that is a lot of horn meant to cross what, 750hz ?
And you'd need a big compression driver too.

That big horn is meant to go low, and no sense going that low with an drivers as small as 8" and 2khz


Shallower horns sound better than deep horns at high frequencies.
Think nice rounded genelec horn loaded domes.

Or put some felt around those horn dome tweets you already have.

Nice tweet, i had the cat378.
My only complaint is the dispersion, narrows the higher up you go.
I enjoyed the cat308.
Erhaps a non ferrofluid would have more detail.

And happy wife, happy life.
I get it.
And space is a premium over there.

Yeah, the CAT378 was my first experience of tweeters beeming and showing horn problems. It has a very pronounced dip at 11k off axis.

But, if the JBL Synthesis Array 8 does it, surely, so can i? It crossed at 1k.
 
Lol, horn compromises.

You are shaping the bubble of sound and gaining output.

I doubt i could hear a 11khz dip off axis.

Are you ready for narrow vertical dispersion on the 9800 ?

I've always wanted to do a double 8" with jbl 2407 in my 54-580 round horns (now un-obtanium).

I'm a deep 2 way fan, needing basically flat to 50hz, and I'm not afraid to boost to get there.
I'm probably 10db boost now.
But my spkr box is 10db down there (ported, qts=.32, fs = 50hz, basically 9db down at fs without eq).

Better bass integration, better snap, better drums, better bass guitar.
Speed is integration.
Been there since double 15s crossing 24db at 750hz to 30" wide jbl 2384 horn (years).
 
I'd say go for it!

Make your version of the Array 8.

Since you mentioned using subs > find an 8" with a bit higher sensitivity ( say 92db ) with an EBP of around 120 hz ( B&C make one or two in this range ) sporting rubber surrounds .

There used to be a DIYSG kit with one of these 8" woofers I'm thinking about ( didn't sell & was discontinued > plus it used a tweeter that P.E. stopped making ). That woofer got good reviews from the designer.

The woofer might have been this one!

Ahh, Here's one of the relevant threads !

Twin 8's below that large horn ( oriented vertically ) would certainly look a lot more balanced ( Feng Shui, etc. ). Would also raise the system sensitivity ( which is good > IME ).

I'd also source a European made ( Italian most likely ) compression driver with no larger than a 3" diaphragm.
- You're better off using a 1" to 1.5" adapter so that you can choose one of a gazzilion affordable ( but good ) drivers with a 44mm ( 1.75" ) diaphragm.

Trust me, the extra depth of the adapter on that horn ( triggering some beaming above 10K) will not ruin your project or compromise the imaging of a sideways H9800 ( as long as the center of the horn is about ear height ) .

:)

fetch
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Thanks earl! I read the whole post. Very interesting and encouraging!

I researched ebp but couldn't find any relation to it being better at 120hz, would you mind elaborating, please?

My initial thought was to make a bass mid that went just below 100hz to crossover to my sealed subs.

GrahamGraham: I know you have stated numerous times you want to base your system on an 8", but could you consider exploring the idea of a pair of corner-horns? There are many designs to peruse, they could more easily accommodate the JBL type horn, play low, fit your room, etc. And they can often be made in more than one section for easier transport. Look at Wayne Parhams Pi speakers for some ideas.

Of course, there would be a lot more challenge in building a more complex cabinet, but, what the heck.

If I was working with your constraints, I'd look hard at 10" drivers in lieu of double 8's. Or try really hard to make something look built in to reduce clutter. Perhaps a pair of stealth furniture cabinets that could play well up against a wall.

Have fun with your project.
 
Thanks earl! I read the whole post. Very interesting and encouraging!

I researched ebp but couldn't find any relation to it being better at 120hz, would you mind elaborating, please?

My initial thought was to make a bass mid that went just below 100hz to crossover to my sealed subs.

Graham,

I simply use the EBP figure to help thin out the herd of possible choices ( from the myriad quantity of possible cone drivers ) before running them through a bass/box prediction program such as WinISD .

As an exercise go find an 8" with an EBP figure above 200hz, then load the parameters into winISD, & then tune it to achieve maximum bass extension.
- do that enough times and you might find a use for the EBP figure.


:)
 
There are a couple designs which use the Faital LTH102 horn(60H x 40V) plus a 1" faital compression driver(I use HF108), with the Faital 8PR200 midbass, plus front 8" woofers. Some use a large 12" - 15" side panel woofer, since when you tilt your speakers in toward the listner there is extra space in the room corners for a deep speaker.

A few designers use the 12" SB34NRX75-6 woofer because it it designed for sealed alignments.... 3.5-4cuft produce -F3~35Hz
 

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