Going 4 way - low mid / mid horns

[Speedysteve7]

Having been 3 way for several months now and liking the conicals, a recent listening session at Mr Coco's, hearing his 4 ways & suggestions 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:-
Getting the horn - well 2 to be precise...

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 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 follow.

[Speedysteve7]

Tonights progress - the mother horn.



Bit of filler and throating tomorrow evening;-)

Should be able to listen to it by Sat or Sunday. Then it's do it all again for the 2nd one...

[Speedysteve7]

First horn is built (not final finished) and it's now playing.
Just dumped it on top of the GRF with the now upper mid horn alongside. Heavy bastard with that monster driver and 1/3 as big again conical!
Have 15dB pad on the 2435 and 11dB on the 2482 - sounds about right vols wise.
Cos there's a 16 ohm driver in the mix on that side the amp was driving the other 8ohm side too loud. Padded that loud side down so have parity. Sound's very nice actually. Bass is great and with presence and the two mids integrate well.
Early days yet of course.
Can't wait to get the missing crossover part (12.6mH inductor) and make the other horn of course...

Once concept is proven I will chop the conicals for the 2435's down as they are only doing highish duty and then think about mounting / what to do with the GRF's.
In the meantime they will fit with the cut down smaller conical I think and the tweeter on a stand.
Or perhaps lay the GRF's on side... Might look a bit weird to start with though.

Oh and a 2" throat looks much larger than a 1.5" one.

Bit more listening - def a nice mid tone coming from the big driver / horn. Detail and feeling the other side cannot match...


A picture says a thousand words...



A simple strap system (4 legs this time as the driver and horn are heavy!) with 4 x 8mm threaded bar applying suitable pressure to the driver from behind. I used some automotive paper gasket between conical and driver for a seal.

[oublie]

now thats fast! you should changer your name to supersonic steve

very impressive how well do horns blend when there are such larger spaces between the mouths (question from horn noob) ?

[Speedysteve7]

Hi oublie,
Once you are back at the listening seat they merge completely and you cannot really hear what comes from where too much. Yes a particular sound at a particular freq can be hear somewhere but that is part of the fun much as you would hear the guitar solo form where the lead guitarist is on a small enough stage.

I made up the crossover (can't be doing with all that cliplead stuff on the floor for too long). The only thing I think I will need to tweak when the other side is ready would be the L-pads.

I might try using the 2842's up a bit higher perhaps 1500 or even 1800Hz - any opinions on that would be welcome. Fairly cheap in inductors to try it...

I have also put the GRF on it's side with the horns side by side on top. Bit too low listening position - need around a 10cm plinth to make it perfect. Too damned heavy once lying down to do much about on my own (they are made of 21 / 24mm Scandi premium ply...

Fun ad games...

[Speedysteve7]

Here's a shot of a lying down GRF



More bass if anything. Paul M's violin bass never sounded so good coming out of that side!
Trombone & horns on Louis A's and Duke E's Together album fantastic tone.

[tinitus]

nice work

hey, I'm working on backloaded midbass horn
my own design
http://www.diyaudio.com/forums/music...r-help-17.html

[Speedysteve7]

Interesting thread that.
Will give it a thorough read tomorrow - bit flaked now. Whole day in the garden enjoying the sun / BBQ with family and then found some time to the cut the other 12 petals needed and assemble into other horn. Glue is setting now. Then it's finishing and throating and mounting the driver.
Hope that delayed crossover part comes soon as without that I can't play

Originally Posted by tinitus

nice work

hey, I'm working on backloaded midbass horn
my own design
http://www.diyaudio.com/forums/music...r-help-17.html

[Speedysteve7]

Made up the 2nd horn

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.

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 but sounded nice and no nasal attributes. I also tried them both with the short adapters 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 horn

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...

[Speedysteve7]

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.

I can hear why I now NEED front loaded horn bass!

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