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Nomex Fun


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#1 Fury♫

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Posted 13 June 2011 - 12:02 AM

Well i've been reading up on unity/synergy horns lately and i'm impressed with a lot of aspects of these designs.
In particular the phase response.
The unity has near perfect phase response because all drivers are placed within 1/4 wavelength of eachother (albeit in a horn), and it is said to give incredible coherence.

Sadly i'm not up to speed to design and construct a unity, nor do I have the time for something so complex just yet (have enough projects on the go), but I thought i'd experiment with some drivers I had on hand and design a speaker with exceptionally close center to center (CTC) spacing between drivers, to see how it impacts crossover points and polar response through the crossover region.

One of my other requirements was the ability to not only play loud, but sound effortless doing so.
Ultimately I would have loved to use high efficiency drivers, but due to wanting to use drivers stashed away in my cupboard, this was not possible.

This is where the Peerless Nomex drivers come in.
They use a truncated basket which allows them to be placed flat against each other.
To meet the "loudness" requirements would mean the use of multiple drivers.

I made a quick sketch of the baffle design I had in mind:
Attached File  new-spkr.png   65.23KB   3 downloads

I then sent this off to Andrew at Aslan Acoustics, and he was more then happy to help cut it out on his CNC and ship it down to me...
The result:
Attached File  Picture 043 (Large).jpg   51.08KB   6 downloads

Tonight I had a chance to load one up with drivers, and this is how it looks :)
Attached File  Picture 045 (Large).jpg   204.38KB   4 downloads
Attached File  Picture 047 (Large).jpg   163.31KB   5 downloads
Attached File  Picture 048 (Large).jpg   212.28KB   6 downloads


The design uses:
Vifa BC25NC tweeters
Peerless Nomex 5" midranges
Peerless Nomex 8" midbasses


I need to get myself some alligator clips to wire these up easily and have a listen.
I'm going to first try them OB, and take measurements of polar response to see what it's like.
I'll then determine if they're suitable OB, or build enclosures for them.
I won't be going quite as overboard as I did with my high efficiency project, although these will get 25mm mdf boxes with bracing.


Also got to play around with my brothers camera, he has a nice Canon SLR with L series lense... Still getting used to it, but took a few pictures of the new Panasonic drill and jigsaw I bought:

Attached File  Picture 049 (Large).jpg   122.08KB   2 downloads
Attached File  Picture 054 (Large).jpg   139.8KB   1 downloads
Attached File  Picture 056 (Large).jpg   81.92KB   1 downloads


:)

#2 romano.inc

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Posted 13 June 2011 - 12:12 AM

looks awesome mate should get nice and loud! jigsaw looks pretty snazzy too haha

#3 Drifte.au

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Posted 13 June 2011 - 12:18 AM

Looks good mate, bet you can't wait to fire them up :)

#4 Sorin-Andrei

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Posted 13 June 2011 - 12:22 AM

Great design - and some awesome tools there too!

#5 Big_Valven

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Posted 13 June 2011 - 01:04 AM

Love some hefty peerless cone area :)

#6 scraverX

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Posted 13 June 2011 - 01:30 AM

I'd really like to have enough space for a decent home system but it's just not viable with book cases everywhere...

#7 muzzy66

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Posted 13 June 2011 - 11:35 AM

Where on earth did you get those 5" Nomex?

A short while ago I was looking everywhere for them and no one had them!

Does Andrew do cutting like this for anyone, or is he just a friend? I could use somebody to cut the baffles on my new hifi project...they are pre painted so I'm worried I'll screw them up if I do it myself :)

#8 Fury♫

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Posted 13 June 2011 - 11:52 AM

Muzzy, I had to buy a box of them - I have spares if you're after some, pm me :)

Andrew will do cutting for anyone I believe. I contacted him through SNA. He's very helpful to DIY'ers :)

#9 Fury♫

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Posted 13 June 2011 - 12:38 PM

Well just hooked these things up for a quick listen and wow, the bass is impressive!
It's "immediate" for lack of better word. It's snappy and it hits nicely.
They go quite low too, and the low end roll off is very smooth (as you'd expect from OB).

There's a blaring in the midrange... Sounds a bit shouty at a certain frequency.
My crossover is very rushed 24db @ 3.5khz between mid and tweeter so this doesnt surprise me.
Also it could be the rear wave reflection as the speakers are just leaning against the wall (well now they're sort of firing out into the hallway from behind)...

When I get a chance i'll measure these...
I've got to build a stand of some sort that won't ruin the baffle, and still enable me to put these in a box if i choose to...

#10 syd-monster

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Posted 13 June 2011 - 12:56 PM

get em off the wall and play with x-over, they'll come good...
Im a big fan of open baffle.... so props on these Danny!
Also you will want them isolated/decoupled of the ground... some rubber feet would help.
I got a HDS project to add on here, but its lower octave dedicated.

Edited by syd-monster, 13 June 2011 - 12:59 PM.


#11 Sierra

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Posted 13 June 2011 - 01:35 PM

Wow Danny ... you are really getting into speaker design in a big way ... very impressive!!!

This is probably a dumb question ... but if you are going to run them open baffle wouldn't a wider baffle have been better?
You're not going to get interference from front and rear waves like that?

#12 Fury♫

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Posted 14 June 2011 - 06:24 PM

Hi Al,
Everything is a trade off... bigger baffles take up more space...
I didn't design these to be used OB, and most likely will build boxes for these, i just figured i'd try them OB first.

:)

#13 SQXPRT

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Posted 18 June 2011 - 12:32 PM

nice,
nice close driver spacing should suit passive crossovers quite well.

#14 268669♫

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Posted 18 June 2011 - 01:02 PM

Looking good Danny,

Nice choice of drivers and a very nice baffle you've got there. Just a quick question, how are you going to get a big enough volume for all those 8's? Or are you happy to roll them off higher?

Ant

#15 Fury♫

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Posted 21 June 2011 - 01:59 PM

Looks like the box for the 4 x 8's will be roughly 2.2 cu.ft sealed.
850 x 280 x 400 deep, 25mm thick walls.

There's enough clean excursion with using 4x8's that if I need to use a bit of eq to bring the bottom end up it's not a problem.

The midranges will take up the space above this (350 x 280 x 400) with a divider between them.

The enclosures will be lined with 25mm thick acoustic foam.

#16 268669♫

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Posted 21 June 2011 - 02:15 PM

Ah OK, 400 deep gives a little bit more space, I was thinking more 300mm deep. Nicely thought out. When are you going to whack these together?

P.S. Dont give them to John......

Ant

#17 Gozza

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Posted 21 June 2011 - 02:21 PM

P.S. Dont give them to John......

Ant


Ouch!

Tough looking setup, your neighbours must really love you ;)

#18 Fury♫

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Posted 21 June 2011 - 02:42 PM

There's a cabinet maker next to Phatt, so going to go round to Phatt on the weekend (either this one or the next) and get them to organise it.
Should be fairly straight forward to build a 5 sided box (front side open as I have the baffle already).

Going to be fun getting them home :P


Then I have to measure them, measure the MorDyn's, build passives for MorDyns, sell MorDyn's, make space for other speakers :P

#19 Captn_Awesome

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Posted 22 June 2011 - 11:31 AM

What happened to buying a house? :P

#20 ~Spyne~

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Posted 22 June 2011 - 12:01 PM

Danny realised he can still mooch between staying at his parents' and Alyce's?

#21 Captn_Awesome

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Posted 22 June 2011 - 12:06 PM

You can still do that and own a house - my brother does. :)

#22 Gonadman2

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Posted 22 June 2011 - 12:59 PM

Haha, my brother does the same thing also! Earns $185k and his home address is a 29ft Bayliner. Owns the boat and pays $3k P.A. for pen fee's (water, power, rates etc).

#23 Fury♫

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Posted 05 July 2011 - 11:00 AM

House clearly isn't as important as a nice set of speakers (or 2... or 3... :P)

:)

#24 Tiger

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Posted 19 December 2011 - 06:19 PM

Ah OK, 400 deep gives a little bit more space, I was thinking more 300mm deep. Nicely thought out. When are you going to whack these together?

P.S. Dont give them to John......

Ant


I just saw this now!!! HAHAHAHAHA!!! Nice one :pp

So THIS is where they went... hmmmm...

#25 268669♫

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Posted 19 December 2011 - 06:49 PM

haha, it has been a while since it was updated so you must have them, lol.

Ant

#26 Tiger

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Posted 19 December 2011 - 07:51 PM

Hahahaha... Nah, I believe these are still on the back burner for a little. Now he has his "bigger" toys to play with finally, he get back to these later on in the new year, I'd imagine.


And your'e right... I don't want them!! :P hahahaha

#27 db-pioneer

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Posted 26 December 2011 - 07:55 AM

I like the look of these aswell