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AK Design Collaborative - Insignia-Class Economy Speakers (a.k.a Indignia)

We haven't talked about baffle layout yet, either.

Am I to build vertical in-line with the tweeter, or mirror-imaging left and right off the centerline, and if so, how much? Woofer's gotta be centered horizontally, as there is no room for offset.

Also, do we want the two drivers as close as possible together, or some space between them?

I'm using plywood test baffles here, which simply mount into a recess on the face of the PE box, so I can try a couple of options. How about I do conventional in-line and spaced a bit as baseline? :dunno:
 
I suppose ideally there would be a bit of offset on the tweeter but lets start with them in a vertical line but maybe keep the distance from the top at a different distance then the side to side spacing to avoid stacking up the diffraction affects at the same freq.
 
RayW said:
When you start designing speakers you gain access to a secret database full of stuff like that. You have to have a special ring and know the daily password.

You dig?

Ray
Click to expand...

Just as I suspected. :sigh: :D


I picked up "Designing, Building, and Testing Your Own Speaker System" by David Weems from the library yesterday. This version is from 1990 so there's not much mention of computer use... only a small MS-DOS program at the back of the book that looks like BASIC. So far I've been enlightened by some of the theories as to what makes a speaker sound good. Right now I'm trying to get a grasp of ports and damping material theory. If I understand what he said, I'm surprised that damping material has the effect of increasing the volume of the box. I had assumed the opposite and would have never thought that it would have anything to do with heat!:no:

I've got a pair of JBL L80s that I'm going to experiment with... I've got a longer tube and some batting. I remember something Gordon said over on the LH forum about improving them that way. Maybe by comparing a stock one to a modded one the light bulb will come on.:scratch2:

BTW, I hope you guys realize how informative this thread is.:yes: I got lost trying to follow the waveguide one, but this one is a real treat.:thmbsp:

Hopefully the mods will make this one sticky when it's done.:yes:
 
RayW said:
When you start designing speakers you gain access to a secret database full of stuff like that. You have to have a special ring and know the daily password.
Click to expand...

dnewma04 said:
I can confirm what Ray said.
Click to expand...

In some states, that could be enough to get you convicted of witchcraft and burned at the stake!:nono::D

I've been looking at a couple of the freeware programs and expected that they would automatically import the data. I think I understand how you did it, though. A lot more work than you guys let on to!:thmbsp:

Keep the layman's explanations coming guys! It helps to remove the glazed look from our eyes.:tresbon:
 
just got pointed here by Zilch from my thread on a 'IKEA' based quasi-open baffle / possibly evolving to a aperiodic box system . . .

http://audiokarma.org/forums/showthread.php?t=162063

gotta say, this is a sweet thread :thmbsp:

I forget sometimes that not everyone has 15 years of speaker theory and DIY under their belt :scratch2: I haven't absorbed the hole thread yet (read the first two pages, skipped to the end - story of my life :D), BUT - for the speaker DIY noobs (not derogatory - I was one once too :no:) this'll be a great resource :yes:

HELL - it took me 5 or 6 complete reads and THEN some to absorb 'The Loudspeaker Design Cookbook' :withstpd:

looking forward to seeing how this thread evolves :yes:
 
We Have Bass!

Closed box, 1" fiberglass damping:

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[Dropped by for the schematic.... ;) ]

Edit: Quasi-anechoic at ~1 M and with LP filter:

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Progress is a wonderful thing, no? :music: It looks great so far; how's it sound?

EDIT: That is the DA175, right?
 
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YamahaFreak said:
Progress is a wonderful thing, no? :music: It looks great so far; how's it sound?

EDIT: That is the DA175, right?
Click to expand...
DA175, yes.

Zaph said it was well behaved in breakup mode. It is.

The filter buries that -30 dB.

We've got good clean bass in acoustic suspension down to 40 Hz in free space, (no boundaries,) I'd say.

I'll cut in the port and install the duct and tweeter next.... :yes:
 
Zilch said:
DA175, yes.

Zaph said it was well behaved in breakup. It is.

We've got good clean bass in acoustic suspension mode down to 40 Hz in free space, I'd say.

I'll cut in the port and install the duct and tweeter next.... :yes:
Click to expand...

:thmbsp: I will continue to watch in amazement. :D
 
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Great work Zilch, I can hardly wait to find out how they sound with a port and a tweeter.

BTW, I think I spied an Optimus/Minimus 7s and an Accurian in the background of your picture at Chez Zilch, no? That's my desk combo too (but older style Minimus 7s).

Lastly, who/what is "Zaph?" A Zilch generated graph?
 
dnewma04 said:
Zaph Audio is a website that does a lot of measurements of drivers and creates some nice DIY designs.
Click to expand...

Thanks dnewma04 (Dave?). And thanks for your interest, explanations and efforts in this project.

This Zilch-driven project (from the cutting edge "Zilchworks" lab?) more or less (probably less), arose as a result of an exchange Zilch and I had in another thread (the "Best $50 speaker" thread). The following was from that thread.

Robie said:
Off thread, but has anyone thought about an AK Design Collaborative DIY design that AK can offer to defray some of its costs? Lots of talent involved here. If the design relied on components from AK advertisers, it might benefit AK supporters too.
Click to expand...

I only mention this bit of background now to repose that "AK benefit" idea should all involved see any merit in it. I don't want to slow down "design development" because a design comes first and it looks like the first prototype is close. In the end, it may be that there is more than enough benefit in just doing the design "live/real time" on AK.

Lastly, Zilch has thrown himself into this project with a vengence and has done a great job keeping it moving forward with your assistance and that of others.

Kudos to all of you who have contributed.
 
dnewma04 said:
Good to see that Speakerworkshop fairly accurately predicted the rolloff. Keep 'em coming.
Click to expand...
It's spot on, looks like, down 10 dB at 2 kHz, -30 dB at 5 kHz, "blip" at 4 kHz.... :thmbsp:

We've apparently got baffle step to deal with (or not,) that wasn't in the original response data. The baffle's only ~1" wider than the driver itself....

Robie said:
I only mention this bit of background now to repose that "AK benefit" idea should all involved see any merit in it. I don't want to slow down "design development" because a design comes first and it looks like the first prototype is close. In the end, it may be that there is more than enough benefit in just doing the design "live/real time" on AK.
Click to expand...
It's 100% AK sponsor Parts Express right now.

If it all works out, I'm hoping for a kit, with a precut baffle, the hardest part.... :yes:
 
Zaph on DA175:

Robie said:
Lastly, who/what is "Zaph?" A Zilch generated graph?
Click to expand...
From this page:

http://www.zaphaudio.com/6.5test/

Comments: This aluminum cone woofer from PE is the value leader in this group and we really couldn't ask for more at this price. The harmonic distortion is good for a driver with a simple motor like this. The response curve is relatively smooth while the breakup node is benign and controlled enough that a notch filter might not be needed if you cross over low enough. The stamped frame surely helps keep the price low but doesn't impact performance too much.
Click to expand...

[Thus far, it's meeting the "Kick-ass" design criterion.... ;) ]
 
Progress

Interior Damping and Baffle Seal:

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Filter stuff, data at bottom of post:

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The one thing that I noticed about the graphed responses that really sticks out to me is the "ZilchLab Grille Cloth Emporium and Spa." That's awesome!
 
Zilch Instructions: Take a break. You did good. Great looking damping, better than I've seen taking a half dozen speakers apart.

While you're relaxin', how do they sound? They certainly look cool.
 
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