[Æ]

John Busch has been building them for quite a while. I had the opportunity to personally audition them at one of our NorCal DIY group get togethers. You can read about it and see the prototype at: http://www.positive-feedback.com/Issue31/lonestar2.htm
Scroll down a bit and look for "The John Busch Room"
Here is a pic of the finished project.

[Lyndon]

Interesting rooms, and gear.
Did John Busch publish his diy plans for these small open baffle, especially the x-over schematics?
That might be a nice project for next year.
Lyndon

[Æ]

Interesting rooms, and gear.
Did John Busch publish his diy plans for these small open baffle, especially the x-over schematics?
That might be a nice project for next year.
Lyndon

From what little I know, yes. He has displayed others too. Take a look at this, http://ncdiyaudio.claub.net/Meet-Spring2010.html scroll down and look at project #14, a brief description is included with three pics. While you are at it, take a look at #13. Tell me if you know who/what those are?

Pic of the backside, from our DIY in 2009.

[Rudolf]

Interesting rooms, and gear.
Did John Busch publish his diy plans for these small open baffle, especially the x-over schematics?

It's all in the Manzanita thread: http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project.html

[Lyndon]

Thanks, Rudolf.  All I got from AE's references were more photos.  I did see the the manzanita reference when I did a search on Busch.
Lyndon

[panomaniac]

LOL.  I wondered what the speaker would be and there they are, the little Manzies. 
They are indeed very good. And there is a new version with a 3" fullrange as the tweeter.

The Peerless woofer is the heart of the system, it's a great driver.  These do need a good bit of power, but that's the trade off for good bass out of a small open baffle speaker.

[Æ]

Thanks, Rudolf.  All I got from AE's references were more photos.  I did see the the manzanita reference when I did a search on Busch.
Lyndon

I only listened to them, never inquired much about them. I had brief conversations with John Busch at the get togethers but never beyond that. Like most bipoles/dipoles his open baffle loudspeakers absolutely need to be pulled out away from the wall at least five feet, maybe even more to sound optimally. That is why I was never particularly interested in building a pair. I just don't have the space, large enough room for listening to them. But they really did sound good, very good.

[Lyndon]

No problem, AE.
But the size of the room also stopped me.  I would still like to hear them.
I keep thinking I would like to build the Metronome, or a version of the Fonken.

[Æ]

No problem, AE.
But the size of the room also stopped me.  I would still like to hear them.
I keep thinking I would like to build the Metronome, or a version of the Fonken.

We had a pair of "Metronomes" displayed at one of out DIY get togethers too.
http://ncdiyaudio.claub.net/Meet-Fall07.html

[JBspeakerman]

Hello All...

Nice to see Bill's Metronomes again!  So well done.  Great build and sonics!

AE, thanks for the positive comments on the Manzanita.  They continue to evolve and now I use a Vifa 3.5 inch as the HF driver.  $12 instead of the $180 for the Scan Speak D3800.   I am now in Texas and because of that was unable to attend the latest NC DIY.
 
Miss the group.  Great folks.

I have been super busy during the last year or so, but now getting more free time.  Working on an update post on the current Manzanita configuration.  Think on balance, the current system is the best overall and at the lowest build cost to date.

So, stay tuned. 



John

[Lyndon]

Keep us up to date, John!  With that price reduction on the HF driver, I may HAVE to build a set.
Lyndon

[JBspeakerman]

Hello all.

In response to Lyndon's request to pass along more info about the current Manzanita, I have been posting over on the original DIY multi-way speaker thread "Fast, Fun, Inexpensive OB Project originally started by Pano 4 years ago.  Wow, 4 years!!

Anyway, you can go there to review the latest.  If members here would like me to also copy this link with all the Info over at DIY, would be happy to do so.  Just let me know. 

John

[Æ]

If members here would like me to also copy this link with all the Info over at DIY, would be happy to do so.  Just let me know.

Yes, by all means, please do so.

[JBspeakerman]

AE

There have been several recent posts on the updated Manzanita over at the DIY Post.  I thought about trying to cut and paste and re-post here, but there is just too much to do it in a practical way.  So think it would be best to provide the link and keep things as comprehensive as possible.

http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project.html

You can of course cut and paste elements you find interesting back here to help keep this thread going.

John

[JBspeakerman]

The cost of the Manzanita, even with it's simplicity continues to increase, so I have been working on a new "Ultra" low cost OB two way of a similar size, and, hopefully performance.  The "Ultra" uses a $26 woofer and the current and or sister Vifa FR for the high end.  My goal is to get back to an under $100 OB with over all performance equal to the Manzanita.  Have produced a couple of mock up versions and the project is good enough to cut some wood.

Will post the project here as it evolves.

[vilbig]

Thanks, John. I had the privilege of hearing some of your designs at this years LSAF. The SQ convinced me that OB is the way to go for my next project. I look forward to the new design.

[JBspeakerman]

Hello All

Here is the parts list for my most recent effort.  I have completed the card board prototype stage and have started to build the first pair with real wood.  I was trying to stay around $100 material cost each, but with inflation being what it is, I am at about $130.00 each including everything but the hand tools needed to build these.  Most of the cost increases lately are coming from the Woofer and large inductor.

This OB is basically a continuation of the original Manzanita theme, but in a floor standing version with minimal fabrication requirements and lowest possible cost.  It is, in some ways better than the Manzanita, but much larger.  I should complete the baffles this week and will post pictures as I go.  One advantage this design has is that it is less sensitive to rear wall distance than the Manzanita and performs quite nicely at 30" and even less depending on the room.

You may want to wait to purchase parts until I have completed the final build.  Just wanted to get this out to show I am moving forward.  A bit more to follow later today. 


Economical Two Way Single Woofer – Floor Standing Open Baffle Speaker Project Parts List

2 Each, ¾” X 24” X 48” Birch or Pine plywood panels.      Home Depot
2 Each, ¾” X 6” X 96” Pine boards (Ripped in half)      Home Depot
3 Each, 2” X 2” X 96” Pine studs (Ripped in half)      Home Depot
1 Each, ¾” X 12” X 48” Pine board            Home Depot
2 Each, 15” GRS Woofers.     (PE 292-415)         Parts Express
2 Each, 3-1/2” Vifa Mid-tweeters TC9FD18-08 (PE 264-1062)   Parts Express
2 Each, Iron core inductors, 16 Mh Erse 16 ga.  (PE 266-960)   Parts Express
2 Each, Resistor, 10 Watt audio grade, 4.7 ohm (PE 004-4.7)   Parts Express
2 Each, Resistors, 10 Watt audio grade, 8 ohm (PE 004-8)   Parts Express
2 Each, Metal film capacitors, 6.2 MFD   (PE 027-236)      Parts Express
2 Each, Air core inductors, 2.0 Mh, 18 ga.  (PE 266-834)      Parts Express
50 Each, Sheet rock screws, 1-5/8” (no. 6) & 26 each cable ties 8”Home Depot
1 Each, Elmer’s wood glue, 6 Oz.?            Home Depot
1 Each, ¼” X 24” X 24” Pine plywood panel (No router required)   Home Depot

Tools:

Small electric or battery operated power drill, drill bit (3/32”- 1/8”) & Phillips bit.
“C” or standard wood clamps, 3” span or larger, 2-4 each.
Saber saw, electric or battery operated with suitable (fine cut) blade for plywood. 
Router with ½” – 1” flush trim bit.
Layout tools including “T” square, tape measure, pencil and makeshift layout compass fabricated from light weight (cereal box or equal) cardboard. 
Soldering iron, solder & hook-up wire (18 ga. Or larger)
Wire cutter – Stripper

[JBspeakerman]

One of the main considerations for this design (was - is) minimal fabrication cost and effort.  Keeping the woodworking at an absolute minimum.  To meet this goal, I based the project around a standard 24" X 48" X 3/4" plywood sheet.  This item is available from Home Depot or Loews.  Both usually keep Pine and Birch pre cut to this size in stock for small home projects.  There is one good side that will accept stain and or paint with minimal sanding prep.  The advantage of getting this pre-cut plywood is that it is easy to transport in most cars, low cost and you do not require a table or power saw.  This is important for a lot of potential builders.

As per the previous post, only two very common power tools are required, a saber saw and power drill.  For a cleaner look, and some improvement in performance, add a router.

The wings can be inexpensive 6" X 48" X 3/4" pine boards.  Sometimes you can find this length in stock, but 96" long is always available.  Both Home Depot and Loews will rip the 96" in half for a nominal or no charge.  Or you can upgrade to white pine or the super expensive (but gorgeous) New Zealand knot free pine. If you take some time and care selecting your boards, you can usually find a nice pair of standard pine boards for the wings.

I will post some dimensional layout drawings soon. This will help show how the baffle comes together and help clarify the following general construction comments.

A router is a great tool if you have one.  If not, you can still build the project.  The router is used to allow for the flush mounting of the woofer and to provide a large rear countersink behind the Vifa to improve rear radiation.  If you do not have a router, you can use a power saber saw to make the woofer cut out and front mount it.  There is an added diffraction penalty, but not enough to seriously detract from the over all system performance.

For the Vifa (again assuming no router) we cut a 6" diameter cut out on the main baffle board .  Then you need a small sheet of 1/4" X 24" X 24" pine plywood to fabricate a Vifa baffle plate.  The 1/4" ply sheet is also available from Home Depot or Loews as a standard item.  ($3.00 I think?)   You then do a standard cut out for the Vifa on the 1/4" ply (as shown on the forthcoming layout drawings).  The 1/4" ply baffle plate is glued and or screwed to the front of the main baffle with the Vifa centered over the 6" cut out.  The 1/4" plywood sheet will have to be reduced in size of course, but this is quite easy with a saber saw.  The Vifa baffle plate is not very elegant, but works just fine.  The edges of the 1/4" plywood can be easily rounded with course sand paper and finished to suit prior to mounting on the main baffle.  The Vifa baffle plate ends up around 7" high and 8-10" wide.

That's about it for now.  Again, when the layout drawings are posted the above will show what I am up to.  A 2" X 2" sub frame need to be built to hold it all together.  The 2" X 2" can be cut with a simple hand saw or saber saw.  More on the sub frame later.  Total project time is 4-6 hours depending on wood working skills and so on.

More thoughts and technical info will be posted as I complete the first demonstration pair.

[Æ]

A router is a great tool if you have one.  If not, you can still build the project.  The router is used to allow for the flush mounting of the woofer and to provide a large rear countersink behind the Vifa to improve rear radiation.  If you do not have a router, you can use a power saber saw to make the woofer cut out and front mount it.  There is an added diffraction penalty, but not enough to seriously detract from the over all system performance.

My router was stolen, but they did leave my Jasper Jig. I have the privilege of using a large cabinet shop but it was recently broken into and everything of value that could be carried out quickly was stolen, including a few of my own personal power tools. Bummer. They didn't steal the table saws because those are too big, heavy to easily move, too big to carry.

[JBspeakerman]

OK, I am back with more info on the New GRS 15" woofer based Low cost OB Project.  Sorry for the delay, have been fighting the flu and other crud now for nearly a month!

I have decided to name this project the "Ultra" as I believe it to be a viable "Ultra Low Cost" design especially considering it's simplicity and the wide frequency band it can cover.  (35-18K +/- 3 db or so).

I have completed the initial baffle and crossover fabrication and will post a few pictures shortly.  The above noted frequency response is obtained with the Ultra placed between 27" and 38" from a sheet rock rear wall surface and measured on axis at about 8' from the front baffle surface.  (ARTA - True RTA & Holm)  The crossover assumes a 32"-34" rear wall distance and offers excellent tonal balance.  As best I can measure a typical "in room" net mid band efficiency is 83-85 DBW and is a bit dependent on rear wall distance.  I bit higher efficiency with less distance, but at a cost of bass extension.  And, conversely, as the distance from the rear wall increases you get a bit lower efficiency but with better bass extension.  With out the rear wall reflection - return, (measured out doors away from rear reflective surface, the intrinsic efficiency is about 82 dbw).

You can drive the speaker to usable levels with 10 - 20 wpc, however 35 - 100 wpc allows the system to reach it's potential.  So a PE Dayton chip amp (300-383) or the very low cost Sherwood stereo receiver 252-125 will do quite nicely and both are available for under $ 100.00 each delivered.  The Sherwood RX-4105 is surprisingly good.  Will it challenge my class A or SET tube units, no.  But for $100 driving the Ultra it works amazingly well.  It clips at around 110 WPC in to an 8 ohm load.  BTW, the power handling of the Ultra is about 100 watts, so the Sherwood or similar mate up well.   Assuming 84 db per watt as a basis for the Ultra, a Sherwood - Ultra combo can easily reach the mid to upper 90 db output level at a 8-12' listening distance.  So for just over $360 and some sweat equity you can have a very capable system.  Just add a CD or other line level source.  Heck, FM of the Sherwood can be quite enjoyable!

As for the final crossover, I am still auditioning the ultra with various amplifier and CD player sources trying to reach a balance the works well overall.  Most of this is balancing the high pass crossover point, trap and pad.  FYI, I see Zaph has measured the Vifa and found it to have a very linear on axis frequency response.  The Vifa for the price is a remarkable driver!

Pics and more info to follow!