Fast, fun, Inexpensive OB project

I'm interested in building a pair of Manzanitas as my first DIY project. (More on the idea behind it here in my introduction ).

I did some research, but still I'm not sure if my room is actually suited for OB speakers, as any speaker would be placed underneath the sloped ceiling/ walls. That on one side there is a window above and a full bookshelf to the side probably won't help regardless of the kind of speaker.

The picture below is taken from behind the listening position, which is about 3m from the speakers and just above this position is the small (0.5m) strip where the ceiling is lever before going down again. At the end of this wall is some soft furniture (couch/ bed).
The room has about 25sqm, walls are made of drywall.

IMG_2840.jpeg


Any thoughts, or even better experiences, if placing OB speaker in a room like this can work, would be highly appreciated!
 
  • Like
Reactions: 1 user
Member
Joined 2021
Paid Member
Hi @Zaubberer ,
my experience with the Manzie tells me that the room behind the speakers would probably be to small.
I used my Manzies in about 1 m in front of the wall and at least in 1 m distance from the side wall.
But - as I don't know how such a room works with an OB (practically you have a funnel behind the speaker which can be good for the bass, or it can kill it, because with the Manzie you can't use the floor effect. In the midrange and treble you could loose the reflections from the rear wall.
It's just my opinion, other may see it different, so let's hope for further opinions.
 
@Plott Thank you for sharing your view/ expectation. I’m curious to see what others might think, but it might just be the case that this part of the room is too problematic for an OB.

In parallel I will think about possibilities of rearranging the room w/o significantly comprising the primary use of the room (it’s my office for up to 40h/week). The desktop is in the best spot so far between both windows and the ceiling on the left is too low for a couch to be useable.

IMG_2844.jpeg
 
music soothes the savage beast
Joined 2004
Paid Member
I'm interested in building a pair of Manzanitas as my first DIY project. (More on the idea behind it here in my introduction ).

I did some research, but still I'm not sure if my room is actually suited for OB speakers, as any speaker would be placed underneath the sloped ceiling/ walls. That on one side there is a window above and a full bookshelf to the side probably won't help regardless of the kind of speaker.

The picture below is taken from behind the listening position, which is about 3m from the speakers and just above this position is the small (0.5m) strip where the ceiling is lever before going down again. At the end of this wall is some soft furniture (couch/ bed).
The room has about 25sqm, walls are made of drywall.

View attachment 1285621

Any thoughts, or even better experiences, if placing OB speaker in a room like this can work, would be highly appreciated!
Looks like great oportunity for corner loaded horn subwoofers...
 
  • Like
Reactions: 1 users
Not sure if anyone wants to take on a new build but figured this was worth posting for historical purposes. John was always tinkering with clever ways to build speakers and loved being able to do it with inexpensive parts when he could.

Back in 2022 I found some old emails from John that outlined his new Manzi build. It had different dimensions and used a front wing in addition to the rear facing wing to increase the output of the woofer. He didn't list the BOM so you'd have to likely play a bit to tune it.

Well another one of John's emails has surfaced. Again, not a BOM but there's a bit more information that might make it easier to build. He gets specific about the woofer filter but not the tweeter.

Somewhere in the two emails he mentioned the woofer was now about as sensitive as the tweeter so it's likely there's little or no padding resistor anymore. The upper frequency trap (the resistor and inductor) are also likely pretty similar to the standard 15" Manzi build as that driver hasn't changed. There's a tad of front wing extending to the tweeter, though. Maybe Pano has an idea what might need tweaking.

And please note, the prices were from 2018. Everything is a lot more expensive now ... but this project has been fighting inflation for it's entire life span.

2022 post:
https://www.diyaudio.com/community/threads/fast-fun-inexpensive-ob-project.110583/post-7148171

The recently unearthed email:

Have completed the upgrade and revamp of the original Manzanita DIY project. Doing everything to keep the material cost at $100 per speaker. Sounds nice... using the $18.00 cheap and dirty PE assembled 80 Hz low pass crossover. No LF trap. So, we are back to a $100 each speaker again that is way better than the original from 10 years ago. Here is how the costing breaks out:

$31 for the GRS
$13 for the Vifa
$18 for the low pass crossover
$3.50 for the connecting terminal cup
$3 for resistors
$7 for the HF trap inductor (18 ga. air core)
$3 for the high pass cap.
$3 for 3 ea. 0.1 MFD by-pass caps
$2 for hook up wire
$2.50 for Euro terminal strip
$3.50 for glue
$10.00 for 3/4" X 2' X 4' MDF or pine ply pre-cut Home Depot handy panel
$2.50 wood screws to mount terminal cup & drivers.

That's my story and I'm sticking to it! The only variable is the wood issue, as prices are all over the place week to week. So at most you may have to add $5.00 or something. A cup of coffee most places.

The cheaper low pass crossover is not as dynamic and cost about a half a db in added insertion loss. But it does a nice job in terms of a near perfect roll off slope. The GRS break up is buried 40 + db down.

The added wing depth and rear mounting the GRS now supports bass well into the mid 30's with out the previous 50 Hz or so peak. Once the web site revision is complete will work up an article for it and flow it through to the DIY site. Still have to pretty the new prototypes up.
 
  • Like
  • Thank You
Reactions: 3 users