Going 4 way - low mid / mid horns

Thought you Zerogainers now Audiosmilers might like to see this...

Having been 3 way for several months now and liking the conicals, a recnt listening session at Mr Coco's, hearing his 4 ways and ideas for improving things has lead to itchy DIY fingers...

The plan is to add a pair of JBL 2482's Phenolic diaphragms.

So a recap of the setup:-
Was
15" Eminence Kappa pro LFII's will run ~20Hz crossing over at 1000Hz in the GRF cabs.
JBL 2435 Be's 1000Hz to 10KHz
Eminence horn tweeters coming in at ~9K upwards.

Planned
15" Eminence Kappa pro LFII's will run ~20Hz crossing over at 350Hz in the GRF cabs.
JBL 2482's will run 350Hz crossing at 1250Hz.
JBL 2435 Be's will run 1250Hz to 10KHz
Eminence horn tweeters coming in at ~9K upwards.

A pair of working but shabby 2482's arrived last night.
They need a bit of a clean up / restoration.
The planned crossover components also arrived (band pass inductors were short by one so I could only test fire one side so far).

Some pics
Beast of a compression driver 2" throat (short horn adapter came with them (I won't use with the planned conicals). A pair made a heavy parcel along with those throat adapters.



Crossover lash-up



Hmm - need to make those conicals


I plan to try the GRF's lying down - this will bring the horn height down and give plenty of space for horn furniture... not sure how the sub 350Hz will work out that way but hopefully it will work.

Here's a shot of the current crossover calcs.



Even without a proper horn the one 2842 is making very nice noises and with a little imagination it's possible to listen & enjoy and I feel this is an interesting evolution on the way to a full 4 way conical all horn system, the 5th way being a tapped bass horn...

Progress updates to come.

 

progress - the 1st mother horn.



After a bit of fettling


The 2" throat looks much much bigger than the 1.5" of the 2435Be... Love large format compression drivers...

Figured out how to mount the driver. Due to weight of both horn and driver 4 fins were needed.



Used a similar pressure the driver onto the throat system as I used on the 2435Be's.
Used some automotive gasket paper for good seal.

Next tried laying down the GRF with horns a top



Sounds better actually.

Only have one 2482 working as my crossover parts supplier were out of the 12.6mH I needed for the other side.

So been running only one side new and one old!

Lovely rich and detailed sounds coming out of the ol' driver!
Integrate really well with both the low freq GRF and the HF 2435Be..

Started the 2nd horn this evening. Will be ready on a couple of days - pesky day job!

Also built the crossover into my external boxes. Enough room for all just about. 'When' I go 5 way I'll need another small box I think or make a new bigger one!

Going to be really interesting / exciting to have a working pair of these.

 

You've really got it bad Steve .

 

hehe -- I'm horny, horny, horny, horny

This is just stop gap... Wait til' the mid bass and tapped horns make an appearance...

 

Progress update;

Made up the 2nd horn (looks the same as the first so I won't bore you with that...

Listening to both mid horns, well all 4 way both sides. Takes a little getting into - very different sound to the 3 way. So much more expression in the lower mid though and putting on stuff I know to check it out.

I do feel I have a bit of a nasal sound on some music. Could be the dreaded honk but it's not really a honk.

I actually have the 2482's crossing at 330Hz not 350 - component values available. They will go higher than 1250 of course. Perhaps will try them at 1500 or so later...

To test some things I tried the 2482's without the horns - as they are phenolic they do not denotate the diaphragms without horn loading.
Quite light on the lower frequencies as you would expect without the horn effect but sounded nice and no nasal attributes. I also tried them both with the short adapters they came with but I preferred the sound without them as the adapters made it beamy.

After that I did some more throat work making sure the sides taper straight to the opening and getting the fit to be perfect to the slightly less than 2" throat as is quoted in the JBL blurb... Also came up with a way to accurately align the driver opening with the hornClick the image to open in full size.

Put them back together and yes they sound better. I think I am running them too hot (need to pad down a bit more). It's quite hard to judge by ear when you drop a new driver in. You have to live with it and try different things and lots of music to get the balance right.
Also measuring is needed to hone - hope to borrow some measuring kit to do that at some point.

More testing this evening...

 

This evening I cracked it. I did some throat blending to the 2482's throat angle, padded down to the same level as the 2435's and wallop - sorted! They are just amazing. Full on, authoritative, detailed, dynamic, powerful, attention grabbing, emotion portraying AND they integrate well with the GRF's and 2435's.

Still reckon another 1 or 2 dB down on the 2482's perhaps. Bit of telly now and then play play play.

Good as the GRF's are, I can hear why I NEED front loaded horn bass now though!

I love DIY... The research, planning, doing, the downs, research, fixes and then the highs!

 

Both sides (still very much work in progress)



Throat. Carefully crafted to let all those lovely mid waves out nicely.


And how it will look when the project is finished


Just spent some time time aligning - well worth doing - much more cohesive now.

 

Gulp!

Very well done Steve. Keep it up.

 

Excellent work Steve.
Are those pics from the new room?

 

what an utopia that is, absolutely a dream super dream, well done,

 

The modest room is the new room the mega room I can only aspire to that - one day!

I am plotting the mid bass and tapped horn. Just need to let the circ saw cool off between projects.

I put the GRF's (still lying down) on low 70mm supports - tidied the bass up nicely and brought the horn throats up to Tannoy driver height.

I was reading up on JBL2482's - apparently the Hammond organ folk are nuts for them, shouldn't / won't use anything else!

 

hi steve, i have all my hi-fi supports made for me from marble but the people that made them for me are now gone, anyway i need two platforms of stone to put under my cheviots i have now got a 2" thick carpet pleased on solid concrete floor any suggestions?

 

Not really - I don't have that problem.
There should be plenty of places that cut and dress marble but at what price.
Tannoys aren't usually that fussy I thought.

Hehe my speakers now weigh about 130KG each with the GRF's big Eminences, big compression drivers, conicals and counter balance weights for them... guess they would press you 2" thick carpet into submission.

Do you find the carpet very dampening? Do you run the level knobs on max?

I have found with the DIY horns I can pad each element to suit the room -very rewarding.

 

hi steve, i solved the problem with out telling the other half , i drilled 10mil spikes on the base platform, poor car pet, as for the c/o levels i almost always have them on level because the way we wired them inside , thanks for your help, i envy you, one day i will win the lotto and buy tannoy co.