Fast, fun, Inexpensive OB project

Hello Donovas Curious. How did you conclude the crossover point is at 3,000 Hz? Acoustically it is around 750 Hz If I recall. Could be off a bit, it has been awhile since I created the design. And the general shape(s) of the woofer and mid-tweeter roll offs are 2nd order acoustically which accounts for the mid-tweeters preferred reverse polarity. John
 
Assume we are discussing the Manzanita Ultra.... the 25" W X 48" H made for efficient use of a standard 4' X 8' sheet of plywood or MDF and with shallow 4" deep wings the combo provided the desired front to back path length to load the woofer to an F equal just below 100 Hz.

The Wharfdale I believe was built with the longer dimension operating in the horizontal position. The path lengths are similar enough not to make a big difference. I went with the more vertical orientation to get the woofer a bit off the floor to minimize floor reflections and to keep the H.F. driver at ear level for a seated listener. John
 
Hi,

I finished my manzanitas 6 months ago, but I was not happy with the response in my room.

I did extensive acoustic treatment (4 big bass traps, diffusers on the ceiling, diffusors and absorbers on the walls), changed the speaker placement, upgraded my electronics (better streamer, bluesound node 2). Now they sound very good.
 

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Nicely done, good job on room treatment. Thanks for the pics! :up:
Do try pulling them away from the wall a bit, and maybe more distance between them. I used to put them near the wall to make room, but pull then out farther for serious listing. They are light enough to make that easy.
 
Hey John,

Yes, we moved the speakers far out into my parents living room the next day and that really made them shine. Big, spacious soundstage with lots of detail and nice tonal balance. My dad is very happy with them, and i would be too (if i had the space for them)!

I came right back to a busy work week so i only just had time to sort through the pictures and pick out some good ones (see below):

The first challenge (after getting the wood cut by our friendly neighbour for a few bottles of wine) was to figure out the rebate to flush mount the Vifa. After some experimentation i think we managed something decent
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Finished baffle. I decided for a relatively shallow rebate to fit the edge of the woofer (which curves down towards the outside). A mm more would also have worked. Note also: don't try to route 18mm beech in one go, you will break the bit :)
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Gluing up. We decided to use both screws and glue, and i think that came out nicely and quite discreet.
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Finished the wood part. We made the base extra long as we didnt know where the centre of balance would be exactly. 20 cm could easily be removed as they are very sturdy.
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finished speaker with crossover and drivers mounted. Caps are claritycap esa. I couldnt get 6 µf so i paralleled 5.6 and 0.33. I also bought another 0.33 which can be added later if needed. The coils are Jantzen.
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Right speaker. As an added bonus, the base also serves nicely as a shelf for various household or decorative objects for added WAF (or a monoblock, for reduced WAF).
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Left speaker, WAF-modified. We did a small 1mm profile on the edges, which adds a nice line that frames the baffle.
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All in all i think they have come out quite well. The wood was cheap 18mm beech intended for shelving (around $20-25 for 1 piece 40mm wide and 2m long). They were not the most square or even (some were a bit wider), but that was sorted out nicely by our neighbour in the cutting process.

Thanks again for the design, this was as good an excuse as any for me to spend time with my dad building something, and the end result is a fantastic sounding speaker :)

TL;DR, this is a serious bang for buck speaker if you have the space. Just do it!

Let me first state that I am most definitely not an OB guy at all, but these speakers are drop-dead gorgeous! How have I not stumbled across these before?

I would love to build a set of these, but had some questions-

Would there be a way to do the crossover at line level? I'm not a fan of speaker-level crossovers, but can easily build something passive or active at line level that could do the job, so long as I have the right numbers. Looks like a high pass on the top, with a baffle step compensation circuit, with the bottom low passed would be a good starting point, and then it's just level adjustment and tweaking.

How would this do with the Faital-Pro 3FE25 up top, instead of the TC9? It is much more sensitive, which could be useful to use flea amplifiers in biamping applications. I just happen to have a design for a very nice flea amplifier, so would love to use it for the upper range :) Otherwise, I have a set of TC9 I could use.

Would it be possible to use the 12" GRS woofer here, with a correspondingly smaller baffle size? I understand the LF extension and efficiency may go down-
GRS 12PF-8 12" Paper Cone Foam Surround Woofer

I have a pair of these on hand, but I doubt they would be worth trying, unless I'm mistaken!
Titan 10" Coated Paper Cone Red Surround Woofer 4 Ohm



As a fun fact- I happen to really have a soft spot for Manzanita, and deal with it fairly frequently. I tend to harvest it from family property up in northern California, and use it for aquarium decoration (aquascaping) and I make jam from the berries :)

Oddly enough, I'm working of a design for a tube amplifier that I'm tentatively calling "The Madrone," and as it so happens, the Madrone is a rather large relative of the Manzanita. Coincidence, or fate? :rolleyes:
 
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Lingwendil Thank you for your interest in the Manzanita project! Your questions are interesting and I will try to answer them as best as I can. As you have likely read in the thread, the Manzanita is more or less a set design. A few of the key aspects of the design are low cost, simple construction, use of off the shelf drivers and plug & play passive crossover. The Manzanita design is an interactive - interdependent system. It is deceptively simple and based on many engineering decisions - compromises. Any major change will require revisiting every aspect of the design.

Once you make any major changes, you are defacto. building a whole new design even though one may not be straying far from the original concept(s). Line level could be made to work, but duplicating interaction of the passive crossover components would be difficult to do. For example, the effects of the large inductor and it's effect on the final woofer - system Q.

The Fatial 3FE25 is a nice driver, but has too many differences relative to the TC9. The Fatial sensitivity advantage would not be of much use as the the system sensitivity is set by the baffle and wing dimensions. I have played with the GRS 12". I just does not work as well as the GRS 15 or the original Peerless 12". It just not clean enough around 300 Hz up. Sounds very muddy and lifeless.

Don't want to discourage you. It is fun to see what others have done with the concept. But most end up with a final build that in very similar to the current version.

As for Manzanita plant family, happened to live just outside of Yosemite for several years. (Now in central TX) And on my CA property I was fortunate enough to have many of the larger version of the Manzanita family. One in my back yard topped out at over 30' with a max trunk diameter of 3'. The large version only grows in a narrow climate zone in the central CA foot hills. Much more common in the family are small scraggly shrubs. Had a few of those too.

Good luck with your design and let us know how it goes! John
 
Something like this maybe, without the ribbon floating above.

I did some searching in the thread and found the post where Klarskov reported on using DSP to delay the Vifa by the equivalent of 5-6cm. It was a slight improvement to his ears.

Is there a reason that the tweeters should be mounted asymmetrically towards the center of the listening position rather than nearer the outside edges, where they would be farther from the listener?
 

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The drawback is stellar interferences!
It would be much better with U shape upside down around the bigger driver .

Troels Gravesen thinks so, too.
Stepped Baffle Study
Maybe I should try for this style OB.

Can any Manzanita builders comment on how this might affect performance and if the crossover will need tweaking?
 

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Oh sooo close. This was last week before putting on a layer of finish. 2 more layers to go and they're done. The other is hanging out in the garage.

I rounded the top edges slightly for aesthetics. I don't have to worry about any WAF issues. The wife is very happy with the way these are coming along.
 

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