Northern California DIY 2004

Post Event Summary:




Activities for the Day:

Speaker Auditions

·        Standard Auditions

·        Contest – speaker which best fits its design goals

Software Demos

·        Soundeasy

·        Praxis




Speaker Audition Summary


We saw a wide variety of designs, drivers, etc. during the day.  Open baffle, single driver, two ways, MTMs, 3 ways, unusual rear channel surround speakers, etc.  The smallest must have been 1/3cuft while the largest was around 7cuft!    At some point, Dave Edeck was worried that things would disappear from the hall, but that wasn’t going to happen with the latter speakers!  We saw some great wood working as well ( more later).


Speakers Waiting their turn (Edwin, Steve, respectively)


Getting Ready to Listen (Barry W)



Auditions In Progress

(Thurman)                                                                    John Jackson Acutons (Edwin H)


John Busch with Giants (Steve H)                                 Andy Newell w/ Open Baffle (Barry W)





Specific Photos/Designs


These are roughly in order of audition.  Only those with photos written up.  Please feel free to send in more comments as I did not get a chance to listen to all of the designs.  More photos would be good too!


Katie Bartas

Read more under “Contest” below.

John Bartas demoing Katie’s  Speakers (Steve H)




John Busch’s or Steve Higgins?   (Barry W)




Andy Newell:  Open Baffle, Tube Amp Driven

These had a really nice cohesive sound.  Made from ElectroVoice 12s.  Far exceeded my expectations for a single large driver.  Treble, for example was fairly extended.  Also, Andy had some really interesting test CDs. 


Mono Block Amps, Preamp

{Steve H}                                                                    {Edwin Y}





Notice corrugated cardboard to disperse waves (Edwin)  



Greg Dallum

Greg demoed two speakers during the day.   See comments below on woodworking.


(Steve H)




Dave Brown


Very interesting rear surround speakers.  Tweeters on front and back.  Rear tweeter can be in phase or 180 out of phase.  Woofer/mids face listener.   From where I was standing, 20+ feet away, I was impressed with the balance of the sound.  I did not get a chance for a close listen.


(Edwin Y)                                                                    (Barry W)                                                       


Speaker Limbo:  Dave just can’t get all the way down to the sweet spot!  (Barry W)  Edwin tries but can’t get there either. (Steve H)



John Bartas

These were really interesting.  At some points sounding quite good, but at some musical passages they interacted badly with the room.  John felt the hard surfaces behind the speakers reflected too much of the rear firing tweeter.   Loved the looks, see woodworking below. 



John Jackson

These had a great sound.   In the tops, in terms of effortless sound, of many speakers I’ve heard.   John really likes the Acuton drivers and I have to agree they sounded great.  Big bucks though!  John also described how fragile they are later in the day.  If you get them, treat them carefully! 


(Steve H)                                                         (Edwin Y)



John Busch

John calls these his “Jokes.”  He says he did it just to prove it could be done.  Well, he did prove it! 


These sounded good (without qualification).  They sounded very good considering the two drivers!    They use an Eminence 18” wide range driver and a SS 3800 series tweeter which is really a mid tweeter.  


John really likes vocals and these did a great job on a wide range of singers.  Very relaxed sound.  No hint of MR integration issues.   David Ortega wanted to make a center channel out of them since the group nixed that idea for his vintage Yamahas (just kidding David). 


(Thurman G)                                         (Barry W)






Ordered alphabetically


John Bartas

By far the most complicated DIY cabinet design I’ve seen in person.  In the top 3 I’ve seen anywhere!.  Its hard for the photos to do it justice. 


Some notes on it:  1.  No parallel surfaces.   2.  The front consists of three panels.    3.  The back has a rear firing woofer and rear firing tweeter.  4.  The side walls are curved.  John laminated three layers of ply together to create the curved sides before cabinet assembly.   John will hopefully post the process to a web site soon as it does not fit any process I’ve previously seen published.   5.  Finish is quite nice. 


(Steve H)                                                                     (Thurman G)


You can see that John executed the design beautifully, but like many of us, he’s gone back and changed things.  Remember, do mock-ups till you are happy with the sound and then build a stunning cabinet.  Many of us, myself included, whish we had! 



John Busch

Impressive sound, but “pullin’ your leg”  on the woodworking.  ;)

(Steve H)


Greg Dallum’s

Great tight fitting cabinets.  Very nice finish.   Greg’s comments on them:  “the speakers that I built were veneered with Tape Ease, 2-ply, red oak.  The edges were routed and inset with solid red oak quarter-round.  The cabinets were finished with Minwax natural stain and Minwax satin polyurethane.”

(Thurman G)



John Jackson

John’s still working on his speakers, but everyone loved the wood used for the top half…

(Steve H)







Contest Summary

Not all people auditioning speakers brought the forms for the contest.  About 7 speakers were entered out of 15 or so auditioned.


The contest required the audience to compare the design intent of the speaker to how successfully that intent was met.  Thus, a pair of really expensive speakers might get beaten by an inexpensive pair because the latter was a better fit with its original objectives.


It turned out that two lower cost designs ranked very high with the audience.  These two were ranked A- and B+ respectively.  


Sorting out the feedback (Barry W)


Winner:  Greg Dallum’s MTs


Here’s Greg’s description of his speaker objectives: 

Summary of Objectives:   I wanted to build 3 pairs of fairly good speakers for my twenty-something kids.  They all live in apartments, so a fairly small size was desired.  I was looking for good extension and driver quality at an affordable price.  I came across the Embla design and it seemed perfect.

1)      Detailed Objectives:

Targeted cost -  approx. $100.00 ea.

Expected completed cost – around $100.00 ea. or $200.00 per pr.

Target listening levels - Mostly low to medium levels (I’m sure that’s a lie!).

Target sound characteristics - Neutral overall, good midrange with some bass extension

i)        Intended listening environment – small to medium living room

ii)       Desired look - Natural wood finish with rounded hardwood corners

Creating the speakers - The box is the same internal volume as the Embla plans but the baffle dimensions were changed slightly to accommodate the extra internal bracing and 7/8” MDF.  I used JustMLS and LspCad Standard for crossover measuring and modeling.  My microphone is an uncalibrated Panasonic WM-61A capsule in a brass wand with a preamp of my design.  The boxes are veneered with TapeEase 2-ply red oak.  Finished with Minwax Natural stain and Minwax Satin Poly.  

2)      Work in Progress (YES / NO ):  NO

3)      Speaker Data:

Type - 2-way passive TM

i)        Alignment - Bass reflex, measured Fb is 56.5Hz.

ii)       Crossover description – Slightly modified Embla crossover.   3kHz. crossover frequency.   The tweeter has a rising response, so the crossover was modified slightly to flatten this out.  Some other crossover component values were changed for my application.

Drivers Used – (1) Seas  P17REX - 6.5” poly. woofer, 8 ohm (Madisound).                                          (1) Seas 25TAFC/D - aluminum tweeter,  8 ohm(PE buyout).



Runner Up:  Katie Bartas’ speakers.       


Katie’s Objectives included low cost, capability to play loud but detailed, and she wanted the wild paint job too!  The speakers used an Audax 210z0 woofer and the Hi Vi Rt2 tweeter. 


Greg’s Speakers (Steve H)                                            Katie and her speakers (Barry W) 






Other Photos


Software Demos

(Barry W)


PartsExpress Goodies

HiVi R1L Round Spiral Planar Tweeter (Barry W)






·        PartsExpress

·        Soundeasy

Event Photographs

·        Thurman Gillespy

·        Steve Higgins

·        Barry Waldron

·        Edwin Yang

Room rental arrangements, onsite logistics, etc. 

·        Dave Edeck


·        Praxis:  Mark K

·        Soundeasy: Jonathan Z

Web Site

·        Steve O’Toole


·        All those who helped with extras such as room setup, room clean up, etc.