Aliquis new 2-way

ugly_woofer

I started these a few months back, because I wanted to take a break from my more complex builds, and build a simple 2 way with drivers that I had on hand.  I'm still plugging away on my minions build, but these are much simpler, just a rectangle crafted from left over wood scraps, and utilizing a Hivi d6.8b and a Dayton RST28f in the visaton wg that has been used a bunch of times-nothing ground breaking here.  One thing that I did notice is that in using a combination of plywood and mdf in the cabinet, it seems to be less resonant, or maybe it's just my imagination.  I don't have any proof.
These were designed to be used with the grill on, and maybe it will provide some ideas for those who would like to use a grill,  as these were constructed with just a table saw and router with a circle jig.  I should also state that these were a quick and dirty build... 50/50's.  Look great from 50 feet or 50 mph.

Kornbread

Just thinking out loud, but when tapping on wood, mdf, whatever, they all make different sounds.  I'd imagine mixing those materials up would have an affect, or is it effect, on the way the box sounds. 

Anyhow, your 50/50 throw it together box looks better than my good ones. 

ugly_woofer

I had the same thought on why it sounds less resonant, but again no proof only theory, maybe someone with a better background in material properties will chime in.

ugly_woofer

Tweeter mounting. M4 x 50mm machine screws for the wg attachment.

rjj45

Very nice tweeter mounting to the WG. Impressed by your precision.

ugly_woofer

Thanks, I  try.

Kornbread

It's people like you who remind me of how much I suk!  You have some awesome builds.    

ugly_woofer

I  was  thinking  about the two different  materials in the cabinet, could it be causing a mismatch  for the propagation  of waves between the panels, not sure how to phase it, an impedance mismatch  if you will.  I don't  know just random thought in my head.

Kornbread

Ever rapped your knuckles on random pieces of lumber (even different kinds of material) at the hardware store?  Notice how different kinds of lumber sound different.  Pine sounds different than oak, manufactured lumber sounds different than solid lumber.  Different sizes of the same thing sound different.  I'm sure it's just my odd and probably backwards way of thinking, but in a speaker box, I'd want those different resonances vs one large one.  And yes, it also makes me wonder if the joint acts as some kind of barrier.     

dcibel

I like the large rounded corners. Your waveguide mounting technique is certainly a lot more complex than what I did.

S7910

ugly_woofer said:

I  was  thinking  about the two different  materials in the cabinet, could it be causing a mismatch  for the propagation  of waves between the panels, not sure how to phase it, an impedance mismatch  if you will.  I don't  know just random thought in my head.

Just a guess, but wouldn't each material/species of wood have it's own resonant frequency based on density  etc. so if several different materials were combined in a cabinet - as done here - the cabinet would likely be inherently more "dead" since the mismatch of resonant frequencies would stop one panel from exciting those it is attached to.

My 2c anyways.

Looks like a fun project!

dcibel

Size of the panels and location of braces will be the dominant factors regardless of material species.

S7910

I will agree that to date that has been the dominant thought among the DIY community.

Kornbread

dcibel said:

Size of the panels and location of braces will be the dominant factors regardless of material species.

I agree, and to an extent, reserve the right to disagree.  They are materials other than wood with vastly varying properties, and combinations of these materials could result in smaller contributing resonances regardless of bracing ... in certain situations.  Stressing a panel also changes its resonance.  Ceteris paribus of course.        

dcibel

I was referring to wood panels, certainly things like solid metals or constrained layers and even the method in which the panels are attached to each other, and the way the driver is attached to the baffle are all contributing factors to the resonant behaviours of a cabinet. My point was that if the difference between one species of wood vs another is having a significant effect to the sound of your speaker, you should consider re-evaluating your bracing techniques, thickness of the material, and cabinet damping as well.

If you think of strings on a guitar, the size of the panel is the length of the string, and a brace is essentially placing your finger on the string. It doesn't remove the resonance, but pushes it higher in frequency where it's amplitude will be lower and will be more easily absorbed by the damping material, and the decay will be faster, all contributing to a less "hollow" sound.  Using a very dense wood vs a soft wood will have an effect for sure, but not as much as the addition of a well placed brace.

S7910

dcibel said:

Size of the panels and location of braces will be the dominant factors regardless of material species.

... or will it?

I realize this link deals with making the soundboard of a piano out of different types of wood, but that is only because I have been unable to find comparable research in the loudspeaker world (and not for lack of looking).

https://www.jstage.jst.go.jp/article/ast1980/17/4/17_4_183/_pdf

dcibel

For musical instruments you want the resonances to live, for music reproduction the intent is to squash them.

Kornbread

dcibel said:

 ... My point was that if the difference between one species of wood vs another is having a significant effect to the sound of your speaker, you should consider re-evaluating your bracing techniques, thickness of the material, and cabinet damping as well.

If you think of strings on a guitar, the size of the panel is the length of the string, and a brace is essentially placing your finger on the string. It doesn't remove the resonance, but pushes it higher in frequency where it's amplitude will be lower and will be more easily absorbed by the damping material, and the decay will be faster, all contributing to a less "hollow" sound.  Using a very dense wood vs a soft wood will have an effect for sure, but not as much as the addition of a well placed brace.

I don't feel any of us here have much of an issue with under-damped or under-braced enclosures.  People on this forum are turning out some pretty sweet high-po builds.  (I'm bragging on you guys, not myself).         

My preference is to brace, or dampen using a two-layer technique, which leaves no unsupported area equal to another.  Braces will be  off-centered or one sidewall may be double layered while the opposing side will not.  The intent is to have many smaller resonances spaced far apart vs one large resonance, or many resonances spaced close together in frequency, which may be possible if all the panels are braced leaving the unsupported areas equal sizes.  This does not mean placing a brace next to a corner and leaving the rest of a panel to resonate.  For instance, I might rip a scrap piece of lumber, and glue x-shaped braces to a large sidewall while running an off-center brace to the opposing side which will have no x-brace glued to its surface.  If it were a pie, no slices would be the same size.   

In the wayback machine (90s'?), Stereophile did a review on an expensive speaker in a thin walled box.  IIRC, the manufacturer supported his design saying something like the box was designed as a living part of the speaker such as a luthier designs an instrument.  IIRC, it got mixed reviews. 

I can tap my knuckles on the back of a piece of solid edge glued pine, solid oak, mdf, or plywood, all boards about the same size, and the sound that comes from the front of the board is different.  This must have some effect on sound transmission and/or resonance, so we will just have to disagree on 'significant'.

   YMMV                              

ugly_woofer

Finished cabinets.  Still have to complete the crossover work and make a grill for the PR.

ani_101

That looks great. Would you be covering the baffle in grill cloth or removable grill?

ugly_woofer

Ani, they get grills, I tried to post the pictures, but they didn't come up the first time.  Ignore the dust and smudges, they weren't cleaned when I shot these.

rjj45

effin' gorgeous, compadre. Love the cosmetics and the classic roundovers!
BTW,how DID you cut the roundovers? 1 1/2 inch router bit? Use a router table?

Kornbread

And how did you get that gloss so nice and even.  I don't see a single wave.   

ani_101

I like this type of grill, where the WG tweeter is flush with the grill. The response should be very smooth, on the flip side, you can't listen without the grills and ogle at naked drivers!

ugly_woofer

Thanks for the kind words guy's.
The roundovers were cut on a router table with 1-1/2 bit.
The glossy finish is automotive urethane clear.  Lots of sanding and buffing.
The satin black front is also urethane.
They are far from perfect, but look good from a distance.
No naked drivers for you!  I find that I get tired of exposed drivers after the newness wears off, and generally prefer the look of grills in the long run, but that being said I also have several builds that are naked.

ugly_woofer

The passive radiator is a Dayton designer series, that currently has no weight added, and I may have to lighten it up in the final tuning.  It's close right now, but the cabinets aren't 100% sealed due to wires for testing.

Ed_Perkins

Kornbread said:

And how did you get that gloss so nice and even.  I don't see a single wave.   

I don't know how Nick did it, but Brad (Hifiside) has a great set of three videos how to do the prep, painting, clear coat and wet sanding.  I learned more from those three videos than anywhere else.  Here's a LINK to Brad's videos.

ugly_woofer

I spray the clear and then wet sand with a backing block using anywhere from 1000 to 1500 grit depending  on how bad of a job I  did spraying it, and I  usually  sand to 2000.  Then buff it out using course compound with a wood pad and polishing compound with  a foam pad, and if you want to go further you can use an ultra fin compound and matching foam pad. 

4thtry

Another excellent high gloss finish, Nick.   Good job!   I've been watching Brads videos and reading the tips from the pros like Brad, Nick, Steve F., etc.   Some day I may figure it all out.   It is a real craft.  I want to figure out how to do this without going to the two part mixing systems (ie., using mineral spirits thinned, oil based primers and high gloss oil based enamels).   

ugly_woofer

Thanks Bill, it's really  not that difficult,  give it a shot, but be prepared for  some elbow grease and a bit of trial and error. 

rjj45

4thtry said:

Another excellent high gloss finish, Nick.   Good job!   I've been watching Brads videos and reading the tips from the pros like Brad, Nick, Steve F., etc.   Some day I may figure it all out.   It is a real craft.  I want to figure out how to do this without going to the two part mixing systems (ie., using mineral spirits thinned, oil based primers and high gloss oil based enamels).   

I've seen some outstanding finishes that used Crytalac in a sprayer, and it's low-voc!