Author Topic: My next speaker build (again...)  (Read 6210 times)

Offline Mongoose

  • Trade Count: (+5)
  • AVForums Super Veteran
  • ****
  • Posts: 608
Re: My next speaker build (again...)
« Reply #30 on: January 11, 2018, 08:25:28 AM »
WTF!

Look at all those holes. Ian, beautiful start to what can only be a beautiful build when done.

Offline Chingy

  • Trade Count: (+46)
  • AVForums Grandmaster
  • *****
  • Posts: 1,287
  • VA Black Widow Trio
Re: My next speaker build (again...)
« Reply #31 on: January 11, 2018, 08:49:37 AM »
always like to start the new year with post from Ian,  :drool: :notworthy:

As always,  :thumbs:
VA BW Pre, Gunter Bolero Mono's, Tannoy Chevoits,, VA BW Mono's, Tara Labs Helix 8 BSM Termination
Power trio (guitar, bass, and drums)

Offline JimGore

  • Trade Count: (+3)
  • AVForums Grandmaster
  • *****
  • Posts: 4,480
Re: My next speaker build (again...)
« Reply #32 on: January 11, 2018, 08:57:15 AM »
^^^ Thanks everyone  :thumbs: 

I have been doing a lot of aluminium work of late with the amplifier build, and I tell you what: after doing some woodwork again for the first time in quite a while I find it rather relaxing and enjoyable.  Something about the smell of sawing a piece of wood and the sound the sandpaper makes against it just awakens a deep calm in me.  A bit weird perhaps  ;D

I am most definitely a "tree hugger", but not for the normal reasons - whilst I really do like live trees (perhaps more than most people), what I really want is the wood that's inside it  :sh1tstirrer:

You seem to have changed your approach slightly with the mid?

You have impressive attention to detail Sir!  Yip, I was scratching around in my cupboard of drivers and found a midrange of somewhat better pedigree and decided to use it.  It's not doing any good just sitting in the cupboard anyway:

SEAS Excel M15CH-002 (E0043) 5" Nextel Cone Midrange:  https://www.madisoundspeakerstore.com/approx-5-midrange/seas-excel-m15ch-002-e0043-5-nextel-cone-midrange/






Standing waves need to parallel surfaces to develop, so that should not be a problem here, seeing that the extensions are at an angle to one another.

Standing waves will develop in an enclosed space, no matter what the shape of the space is.  The reason for the non parallel walls is to try and avoid high Q standing waves.  If you have parallel walls, then there is a specific frequency which has a wavelength (and 1/2 or 1/4 or even 1/8 wavelength) which corresponds to the distance between the parallel walls, so when the driver plays any of those "magic" frequencies, those standing waves are activated and it colors the sound. 

Why does it color the sound?  Because that standing wave doesn't dissipate very quickly, and portions of it gets "transmitted" back out through the back of the driver, thus causing "smearing" of the sound you end up hearing.

The non-parallel walls will still have standing waves, but not too much at any specific frequency as caused by parallel walls, thus the standing waves that do exist are (normally) of a low Q, thus you can damp them out much easier inside the cabinet.

By the way - this is also the reason that a sphere (perfectly round ball shape) is probably the worst because every distance inside the cabinet is the same.  The second worst thing is a perfect cube, and the third worst is rectangle where you have one side being half or double the length of any other side.

Fun!



WTF!

Look at all those holes.

 :giggle:  That's nothing.   Wait until you see the rest  :rubhands:




Update:

The next thing I did was to cut large chamfers into the back of the baffle so the drivers can breathe a bit easier.  Kind of like "porting" the heads on an engine...

This was done by using my handheld router and a massive chamfer bit - the mass of the bit is serious, so when you switch the machine on in free air the angular momentum actually tries to turn the router sideways in your hands.  A bit of a scary thing to be honest, so this is done very carefully and with full concentration.








Next I milled the braces as well as the top and bottom plates.  This is 15mm Birch ply:

First all the holes are drilled and screws used to ensure everything is fastened down well.  I don't like to take chances, so there are about 50 screws (give or take):




Then I have MountainMan make a 2.5mm deep profile cut using a normal 2 flute router bit.  This is done because I want the edges of the cuts to be nice and clean with minimal splintering:




And then I change the router bit to a 2 flute carbide slot drill (end mill) which goes all the way through the plywood:




So here we have a set of braces for 1 speaker cabinet:




...and the offcuts left on MountainMan:




Kind regards,
Ian.

Offline XL1000

  • Trade Count: (+76)
  • AVForums Grandmaster
  • *****
  • Posts: 1,388
Re: My next speaker build (again...)
« Reply #33 on: January 11, 2018, 10:36:08 AM »
Hi Ian


My all time favorite speakers have been with me now for almost a decade. The Mission E55's.
I find them really quick, easy on the ear at high volume and look just brilliant!!!
Your design for this build is really exciting.  :rubhands: I hope to hear them in person one day soon.
Here is a photo of what the E Series Mission look like. Just today I managed to acquire the matching surrounds E80.





I will follow this build with great interest.  :dop:
Music is a moral law. It gives soul to the universe, wings to the mind, flight to the imagination, and charm and gaiety to life and to everything. Plato

Offline Dubya Jay Dee

  • Trade Count: (+3)
  • AVForums Veteran
  • ***
  • Posts: 386
Re: My next speaker build (again...)
« Reply #34 on: January 11, 2018, 11:41:42 AM »
Excellent build skills!

Please tell me you make kids toys with the leftover cutout bits & "wheels"..hehe  :thumbs: ;)

Offline cybasoul

  • Trade Count: (+2)
  • AVForums Super Veteran
  • ****
  • Posts: 669
Re: My next speaker build (again...)
« Reply #35 on: January 11, 2018, 01:34:33 PM »
Ian at his best...Unpredictable at times, I bet this is what will be used and not the boards they cam from  :2thumbs:
...and the offcuts left on MountainMan:



Offline El Sid

  • Trade Count: (+11)
  • AVForums Grandmaster
  • *****
  • Posts: 1,028
Re: My next speaker build (again...)
« Reply #36 on: January 12, 2018, 11:07:12 AM »
Ian - where do you get your birch ply from?

Offline JimGore

  • Trade Count: (+3)
  • AVForums Grandmaster
  • *****
  • Posts: 4,480
Re: My next speaker build (again...)
« Reply #37 on: January 14, 2018, 08:06:39 AM »
^^^ Thank you for your kind words everyone  :dop:

My all time favorite speakers have been with me now for almost a decade. The Mission E55's.
I find them really quick, easy on the ear at high volume and look just brilliant!!!
Your design for this build is really exciting.  :rubhands: I hope to hear them in person one day soon.
Here is a photo of what the E Series Mission look like. Just today I managed to acquire the matching surrounds E80.

That's great man - well done!  I have never heard these speakers - wouldn't mind having a listen sometime, especially when they come with such a stellar referral!


Excellent build skills!

Please tell me you make kids toys with the leftover cutout bits & "wheels"..hehe  :thumbs: ;)

I have been wondering what to do with all these little round bits.  Not a bad idea, though not too sure how much fun my daughter will have with wheeled toys  :thinking:  Perhaps more than I think  :rubhands:



Ian at his best...Unpredictable at times, I bet this is what will be used and not the boards they cam from  :2thumbs:

Lol  :BWAHAHAH:



Ian - where do you get your birch ply from?

I buy from a place called universal plywood.  https://www.universalply.com/




Time for an update:

So here I have the braces cut for the pair of speakers - all nicely stacked together:





Next I do a quick dry fit to see that everything lines up reasonably well:










So now I need to find a way to get the alignment right when I do the glue-up.  I use 6mm wooden dowel pins for this.  The CNC machine drilled the dowel locations into the back of the baffles for me, but it cannot drill the edges of the braces (they are too tall), so that will be done by hand.  Because it's for alignment purposes this needs to be fairly accurate.  Now I don't know about you but my hand drilling skills aren't the best, so to remove the potential for frustration I make a quick drilling jig:










So the brace fits in like this (front side):




Then I drill it like this:




And here I do the back side:




...Finally I do some router work to get all the edges nicely rounded off:







This small end here was rather tricky to do, but I managed fine:




The end result:







Cheers for now!

Kind regards,
Ian.

Offline JANNAS

  • Trade Count: (0)
  • AVForums Super Veteran
  • ****
  • Posts: 541
Re: My next speaker build (again...)
« Reply #38 on: January 14, 2018, 10:43:43 AM »
Superbbb job Ian !! :2thumbs:

Offline itscraig

  • Trade Count: (+34)
  • AVForums Grandmaster
  • *****
  • Posts: 1,196
Re: My next speaker build (again...)
« Reply #39 on: January 14, 2018, 04:47:18 PM »
 :faint:
absolutely astounding

Offline JimGore

  • Trade Count: (+3)
  • AVForums Grandmaster
  • *****
  • Posts: 4,480
Re: My next speaker build (again...)
« Reply #40 on: January 15, 2018, 10:01:13 AM »
Next job was to assemble the midrange "triangle".  This is what will help keep all the ribs true and aligned.

Step 1 - glue and clamp the center brace to the top:





Step 2 - glue and clamp the divider to the center brace:





Step 3 - check for square:





Kind regards,
Ian.

Offline JimGore

  • Trade Count: (+3)
  • AVForums Grandmaster
  • *****
  • Posts: 4,480
Re: My next speaker build (again...)
« Reply #41 on: January 15, 2018, 11:05:54 AM »
The next thing was to cut the back panels of the speaker.  These are very narrow and have a "difficult" angle on the sides.

First I measure the included angle on one of the braces.  Start by getting a reference measurement:





Next we measure the actual angle:




The I take half the measured angle and set the tablesaw blade:




And then I saw out the back panels:




Which in turn get drilled for the location dowels:




Next I insert dowels pins into the braces and do a dry assembly to test the fit (no glue):




So here for the first time we see things starting to come together.  Still no glue:




Fit looks good:




























Looking interesting  ;D

Kind regards,
Ian.

Online HBAutomation

  • Trade Count: (+12)
  • AVForums Super Veteran
  • ****
  • Posts: 838
Re: My next speaker build (again...)
« Reply #42 on: January 15, 2018, 12:41:22 PM »
 :notworthy:    Oh and that Angle Cube is awesome!
When You Come to a Fork in the Road, Take It!            [Yogi Berra]

Offline cybasoul

  • Trade Count: (+2)
  • AVForums Super Veteran
  • ****
  • Posts: 669
Re: My next speaker build (again...)
« Reply #43 on: January 15, 2018, 01:06:16 PM »
WOW

Offline fuz940510

  • Trade Count: (+7)
  • AVForums Super Veteran
  • ****
  • Posts: 623
Re: My next speaker build (again...)
« Reply #44 on: January 15, 2018, 02:18:47 PM »
Stunning work, as always!

Out of curiousity, why the choice to go Bass Reflex, rather than say a multiple entry quarter-wave enclosure? It's something i've read a lot about, but never got my head around. Intuition says that modelling it would be the first issue, and getting a relatively compact box the second
If you want to be taken seriously, always check your fly.