Getting the horn + well 2 of them...

[Magna Audio]

Been writing this up on the wam but cross pollination is good...


After hearing Mr Coco's conical horns - esp when attached to Vitavox S2 drivers I must say I was impressed.
What sealed it was hearing them in my own home with lash up crossovers - they sounded mighty good! The GRF cab doing all the lovely mid bass and bass stuff of course!

A long informative chat with Mr Coco on what sort of compression drivers would be good set me a researching. One idea was just to get a pair of AH-300's like I'd heard.
Know what i am I getting and all that. But the price tag is quite stiff - $2700 full price and who knows if you get customs and vat on that as well.
Saving up for a pair of nice Vitavox S2's would be pretty expensive too!

Another idea was to have the wood cut by someone like Avon ply but they and all the places I tried ran a mile from this one - I guess too time consuming to do with a realistic price / to Avon's very exacting standards...

So could I cut 24 angled / tapered slats with simple DIY tools in my workshop? They challenge was on!

First some design - I have a pal who is a whiz with cad - he drew this up from my description and dimensions kindly supplied by Mr Coco.
We exchanged emails about horns, how far down the throat it was and mouths etc. Not to be traffic'd on corporate email you understand!

Here is the CAD drawing of what was to be achieved...

http://inlinethumb08.webshots.com/39943/2681784500071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2681784500071997495jHaMPT)

From what my CAD pal told me the cut angle needed would be 15 deg, Taper from 124.5mm down to 22.2mm - 0.2 of a mm, nice!

Mr Coco sent me an interesting link to a cool dude who had made similar cones but even bigger

http://sites.google.com/site/diyfirefly/100-hz-multi-sided-conical-midbass-horns

On that site is a link to a cool little calc prog that tells you what cut angle you need for an any number of sides pyramid...

http://jansson.us/jcompound.html

That calc was not saying 15 deg at all but 13.8!
So back to CAD pal who said "It is definitely 15° (hold down Alt + 0176) on the flat faces ... so I did a quick cut through the cone and then measured the resulting face angle - low and behold 13.886°
Didn't think to check that it would be different once off the flat surface, but of course, it will change as the slat is leaning inwards as well."

http://inlinethumb12.webshots.com/44363/2366629640071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2366629640071997495jlkOUv)

Out popped the concurring angle!

I was all set - well not quite. 13.88 deg would be hard to dial in on my trusty Wickes circ saw!

Next to mark up some wood and get cutting. I don't like waiting around...

http://inlinethumb42.webshots.com/33065/2226826480071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2226826480071997495OYzGVe)

I don't have a saw as cool as the dudes so I used this.

http://inlinethumb21.webshots.com/1236/2530069710071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2530069710071997495lrAsNc)

http://inlinethumb32.webshots.com/36575/2855688280071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2855688280071997495ithdoM)

Here is a stack of 12 petals put roughly together...

http://inlinethumb06.webshots.com/45829/2995730210071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2995730210071997495XkOGEV)

And once glued together - no fancy clamps - I put PVA glue on all the edges and stood it up like a wigwam and worked it into position. Then put a large stretchy strap around the bottom weighted on for the base and a small one for the top.

http://inlinethumb45.webshots.com/48044/2758261900071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2758261900071997495utZtQC)

Quite strong enough for it to fall from standing up on the thin end and twat the heavy large end on the floor and take it!


That's all for the time being... Tune in later, for more Around the horn!

[Magna Audio]

Drivers... Having trawled the net for suitable drivers and 435Be's and 2435's being the commercial sister of the 435's I came across a pair. JBL 2435 1.5" throat, Beryllium dia and Neo mags. Nice spec and very affordable. Course, don't know how they will sound...
X/O around 800 to 1000Hz should be doable.
Plan is to start off with the Tannoy X/O'er and move on from there...

Hopefully they will arrive this coming week.

Here's a pic of what I am trying to achieve - the lovely AH-300's

http://inlinethumb41.webshots.com/47848/2125040070071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2125040070071997495tOwsAA)

Oh and some nice boxed X/Overs and stands to support them :)

The conical masters site - http://www.acoustichorn.com/products/300/
Personally I think those red edge addo-ons look well dodgy but like the the simpler sleek ones at the bottom / as Mr Coco has...


After a bit more (ahem, lots more) work there were 2.

http://inlinethumb03.webshots.com/47554/2840722740071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2840722740071997495vjxJIZ)

Now the throat thingies are said to be pretty critical so no just bodging something up.
Need to match the 1.5" drivers and be nice and true so the temperamental little soundwaves stay well behaved as they make their bid for freedom!

AH-300's have petals that fit inside a cast ali machined throat adapter. This takes the flat slats from well, flat, to round over about 3".
I decided to do this using high tech 2 pack wood filler. This clever stuff blends into birch ply perfectly when you varnish it with mellow varnish.

http://inlinethumb48.webshots.com/45871/2748801400071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2748801400071997495cGmpqU)

Close up of throat.

http://inlinethumb28.webshots.com/45979/2548175300071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2548175300071997495VEqvMO)

Still needs final filling and throating to be pass my exacting standards but all in all I reckon it'll work.

a horn's eye view (final truing still left to do).

http://inlinethumb15.webshots.com/19406/2167647130071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2167647130071997495oTWbcQ)

Apparently a rough'ish throat is good - so perhaps after first / 2nd varnish some sanded varnish like you use on sailing dinghies hull floors for grip is the ticket.
I've used that from my Mirror dinghy sailing days...

a quick snap of how they would look on the GRF's. Pre mellowed!

http://inlinethumb53.webshots.com/44468/2325924810071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2325924810071997495gXYwGg)

For those of you who followed the dedicated music room thread, Yes - the room has been changed around. Needs long speaker cables but long TNT Ubyte2's do work very well (much better than short ones for some reason) and 'we' are happier with the room like this as it means open to the patio door and you can look out + I sit close enough to the hifi rack to lean over and adjust the volume!
Cannot discern any loss in sound qual due to longer speaker cables and if anything the acoustics are better - perhaps not having a patio door behind the listening position helps?

Have to move the cave painting my daughter did for me to the other wall...

Now I await drivers to make up the fins to secure the driver to the back etc. If ever going to use Vitavox S2's then a nice birch ply machined adpater suitably threaded on my lathe to screw on to the driver would be my preferred solution. Could perhaps impreg the thread with superglue to make it super strong / hard (DIY Panzerholz...) There are many ways to skin a cat.

[Magna Audio]

Collected the drivers - tiny little things compared to the Vitavox S2 and the big mumbas of RCA that Mr Coco is currently using...
Will they do it?! All share a 1.5" throat. 2435's have a pretty shallow back compared to their consumer 435Be cousins... Perhaps they need modding to give more volume behind the diaphragm? A nice lathe spun ring of nylon or birch ply came to mind...
Anyway a bit of measuring and a few saw cuts later and the the drivers are in place. Did not want to do anything too permanent to my conicals so went for a simple clamp the driver in place.

http://inlinethumb37.webshots.com/45604/2092649220071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2092649220071997495FdmKHd)

Those thoughtful JBL people put a rubber thin gasket on so perfect to get a gas tight fit. My solution uses felt pad cushioned threaded legs to press the driver on to the throat mounting face.
Works a treat! Easy to align and very secure with M8 and threaded birch ply plate. Birch ply rules

http://inlinethumb04.webshots.com/44803/2519438650071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2519438650071997495sKgffN)

Here's how they look from the front.

http://inlinethumb59.webshots.com/25082/2240039950071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2240039950071997495uBotqU)

Currently sitting on blutak and books and bungie strapped down at the rear - not going anywhere...

Plan was to run them up and see... Quick look at the Lpad calc that Mr Coco sent me... 12dB to start with. Just about had the parts to make it as Farnell did not deliver the 1 ohm'ers I ordered

Some of those special clip leads and time to power up the amp having checked everything over once again.

Moment of truth...

Ok they are working. Bit more vol - pop up and stick head in horns and to bass. all doing as should. Back off and turn up a bit. Hmm sounds pretty all right actually.

Crossover is Tannoy so working ~ 1000Hz. Plenty of bass and very clear mid and treble. At vol perhaps a bit too much bass perhaps, can fix that... Back to the calc - what does 11dB need.
Hold on this is CD for test. Lets try the vinyl first then see + this is a pretty bassy CD at that...

Here they are working...

http://inlinethumb35.webshots.com/46626/2712525220071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2712525220071997495oQflhc)

Reckon there may be a lack of mid, noticeable on some stuff. Mr Coco's measuring will tell that...
Mod the rear chamber of the drivers and roughen throat spring to mind.

Many thanks to Mr Coco for bringing his gear here for me to hear and patiently answering all my dumb questions and helping me learn along the way...
Still need help with the crossovers proper I think...

So what have we got? On the road to some pretty decent sounding horns I think, nice bass weight I can adjust, all on a very low budget indeed. Done in less than 2 weeks too.
Listening closely - you just don't hear what is coming from where, GRF or conical - that's a good thing right...

What's more the wife thinks they look nice - no telling with them is there?!

Plenty more tweaking left to do - all part of the fun!!

Now AoS is up to date:-)

[Ali Tait]

Fantastic work Steve,very impressive! Like to hear these sometime.

[Techno Commander]

WOW!! Epic project. They certainly look the part and if the sound matches the look, they should be superb. JBL compression drivers have a seriously good rep in the pro world too.

[Dave Hewitt]

Superb job Steve,bet they sound the biz.
Dave.

[John]

Nice work would love to hear them sometime

[Tripmaster]

Excellent :eyebrows:

It could also double as a hat/lamp shade

[DSJR]

You've got it bad Steve, REALLY bad :D

Excellent workmanship as always, VERY well done!!! :respect:

[Beechwoods]

Wow! Beautiful! They look great! I wish I was good with wood too...

[Magna Audio]

Yes I have it bad - but it's so good.

Had a really good listening session last night and opened the rear chamber hole on the drivers - just the stiff JBL label to take off (without damage) and there is a hole through. This leaves the rear chamber open to the air effectively increasing the volume some think. What def made a bigger impact is positioning. You can have from hard attack in your face but oh so clear and focused to softer and more diffuse all by angle out / upwards a bit.
This meant I could down the dB damping from -12 to -9 or -10 and get more mid loveliness and better balance.

My wife sat and listened for a couple of hours - partly due to the new room having a pair of seats in the sweet spot I think and also partly she is very sensitive to anything grating and these mids do not grate at all they are very pure and non-fatiguing.
Measurements this evening will be interesting.

[Magna Audio]

Time a little update as a few developments have occurred.

1. Out with the Eminence Pro's and in with the LF as in Low Frequency versions!
Boy do they do nice sub bass but pull of the neat trick of being as good on mid and upper bass.

I had gone back to the HPD's for a test and liked them quite a lot but there is a bloom about them that the Eminence just portrayed realistic bass instead of, and the LF's are amazing at BASS. Been playing all sorts of bassy stuff over Spotify that I don't own.

An adapter ring made up to fill 8" hole to the 6" hole the Tannoy HPD, Golds etc requires.
http://inlinethumb17.webshots.com/46672/2494493620071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2494493620071997495KvQVMC)

I made some tabs to stop the ring pushing in. Here it is in place all sealed tightly with good ol' felt
http://inlinethumb18.webshots.com/47121/2582299330071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2582299330071997495FBuYKp)

I was using JBL 2405 tweeters that are ok but nothing special.
Curiosity got the better of me about the Eminence horn tweeters - they supply Maplin but in a 600w version:steam: but you can get a 75w version for a song.
Plumbed them in and Lpad'd suitably and they are just fine!

Then I time aligned the mid and tweeter and this gave a sharper image and better space / placement of the performance.

I am very happy with the way it sounds now... until the next big thing:)

Some pics.

http://inlinethumb23.webshots.com/44374/2407624440071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2407624440071997495czVxJd)

http://inlinethumb04.webshots.com/48195/2861008410071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2861008410071997495bTPiJe)

http://inlinethumb34.webshots.com/32097/2130673540071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2130673540071997495ltdhoE)

Now with added LF
http://inlinethumb51.webshots.com/38194/2071635580071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2071635580071997495iWbtpI)

Must get around to varnishing the bare birch ply sometime...

[Magna Audio]

Time a little update as a few developments have occurred.

I had gone back to the HPD's for a test as the Eminence lacked low bass I felt and this was confirmed. I like the HPD / Golds bass sound quite a lot but there is a bloom about them that where the Eminence just portrayed realistic bass instead.

An adapter ring made up to fill 8" hole to the 6" hole the Tannoy HPD, Golds etc requires.
http://inlinethumb17.webshots.com/46672/2494493620071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2494493620071997495KvQVMC)

I made some tabs to stop the ring pushing in. Here it is in place all sealed tightly with good ol' felt
http://inlinethumb18.webshots.com/47121/2582299330071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2582299330071997495FBuYKp)

Then I ordered up some Emience Kappa Pro 15 LF-2's. Same Kappaness but with added Low Freq. Bigger magnet etc.
Boy do they do nice sub bass but pull of the neat trick of being as good on mid and upper bass.
Been playing all sorts of deep bass stuff off Spotify to test the low capabilities of these.

I was using JBL 2405 tweeters that are ok but nothing special.
Curiosity got the better of me about the Eminence horn tweeters - they supply Maplin but in a 600w version:steam: but you can get a 75w version for a song.
Plumbed them in and Lpad'd suitably and they are just fine!

Then I time aligned the mid and tweeter and this gave a sharper image and better space / placement of the performance.

I am very happy with the way it sounds now... until the next big thing:)

Some pics.

http://inlinethumb23.webshots.com/44374/2407624440071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2407624440071997495czVxJd)

http://inlinethumb04.webshots.com/48195/2861008410071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2861008410071997495bTPiJe)

http://inlinethumb34.webshots.com/32097/2130673540071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2130673540071997495ltdhoE)

Now with added LF
http://inlinethumb51.webshots.com/38194/2071635580071997495S600x600Q85.jpg (http://entertainment.webshots.com/photo/2071635580071997495iWbtpI)

[John]

As usual excellent work Steve

[Spur07]

looking good steve. I particularly like the use of the books as counter balance. :)

[Ali Tait]

Yes indeed,nice job Steve. Like to hear these sometime.

[Marco]

Same here - fantastic stuff, Steve! :youtheman:

Marco.

[Magna Audio]

Thanks guys.
Somehow I got a double post... I was editing and things went wrong connection wise, now there are two slightly different posts:-)