Russellc: Good that you are taking the plunge!!
The original stand mounted Manzanita using the GRS-15 has a calculated efficiency of around 84.5 DB/W. The larger Ultra is about 86.5 dbw. These efficiency ratings are good into the mid 40's on the Manzanita and lower 30's on the Ultra. The above frequencies are where the speakers BEGIN an initial 6db / octave roll off.
Your First Watt clones will be ideal for either speaker. If you build the Ultra, you will likely hear and feel bass you never knew was there and you will be able to recognize what instrument was used to create it! My point being the above efficiencies are real throughout the spectrum with none of the "harmonic doubling" so common in box speakers. Many box speakers start rolling off in the upper 50's to lower 70's area while claiming to be 88-90 DB/W! By the time they get into the lower 40's, they are more like 81-83 DB/W efficient. Enjoy!!
The original stand mounted Manzanita using the GRS-15 has a calculated efficiency of around 84.5 DB/W. The larger Ultra is about 86.5 dbw. These efficiency ratings are good into the mid 40's on the Manzanita and lower 30's on the Ultra. The above frequencies are where the speakers BEGIN an initial 6db / octave roll off.
Your First Watt clones will be ideal for either speaker. If you build the Ultra, you will likely hear and feel bass you never knew was there and you will be able to recognize what instrument was used to create it! My point being the above efficiencies are real throughout the spectrum with none of the "harmonic doubling" so common in box speakers. Many box speakers start rolling off in the upper 50's to lower 70's area while claiming to be 88-90 DB/W! By the time they get into the lower 40's, they are more like 81-83 DB/W efficient. Enjoy!!
really new to this and planning something similar with an FR driver, just trying to piece some things together. Edge is showing roll off from 400Hz hitting 0dB at 100Hz for this baffle, driver size isnt affecting the roll-off either. Am I using/interpreting it wrong or this accurate?
Finished these up over the weekend. Listened to some rock and roll before my little Lepai decided to give it up (don't think it liked 16v). Sound was great, loved the bass and the room filling sound. I thought the highs might have been a little "ringy"? Maybe just the amp or the room...
I mistakenly ordered the crossover parts for the Ultra, but found somewhere on the thread that this would work for the smaller model so I went ahead with it. I have all the components set up so I can switch stuff out and educate myself some on speaker sound. Any suggestions would be appreciated.
Tried to stick to specs but the baffle is just 1/2". I had a sheet of phenolic I wanted to use and since it is stiffer than 3/4" ply I thought it would work ok.
Many thanks to John and Pano and everybody else on the thread who made this design comprehensible to me!
I mistakenly ordered the crossover parts for the Ultra, but found somewhere on the thread that this would work for the smaller model so I went ahead with it. I have all the components set up so I can switch stuff out and educate myself some on speaker sound. Any suggestions would be appreciated.
Tried to stick to specs but the baffle is just 1/2". I had a sheet of phenolic I wanted to use and since it is stiffer than 3/4" ply I thought it would work ok.
Many thanks to John and Pano and everybody else on the thread who made this design comprehensible to me!
Attachments
Cool! Looks good in black and tan. 
@laserscape. As far as I know, edge doesn't show you bass rolloff according to driver size. I think it assumes that the driver is flat from way down to way up. The size of the driver just changes how it reacts with the baffle edge.
Take the results with a grain of salt. I haven't found close matches between Edge and live measurements. It's a good general indication, but not super close in my experience.
@laserscape. As far as I know, edge doesn't show you bass rolloff according to driver size. I think it assumes that the driver is flat from way down to way up. The size of the driver just changes how it reacts with the baffle edge.
Take the results with a grain of salt. I haven't found close matches between Edge and live measurements. It's a good general indication, but not super close in my experience.
Cool! Looks good in black and tan.
@laserscape. As far as I know, edge doesn't show you bass rolloff according to driver size. I think it assumes that the driver is flat from way down to way up. The size of the driver just changes how it reacts with the baffle edge.
Take the results with a grain of salt. I haven't found close matches between Edge and live measurements. It's a good general indication, but not super close in my experience.
yeah, in practice the bass turned out to be good. baffle rolloff isnt any more of issue with an OB FR driver than a woofer I dont think, the real problem being limited bass quantity from low sensitivity and excursion limits, woofer helps wih that along with usual WAW benefits. easy to understand why its recommended but it definitely seems like you can have good open baffle results with a lone FR driver.
I've tried a few OB with 1 fullrange drivers and never liked them much. I could never get a correct tonal balance. With a coax, yes - but that's a 2-way with crossover.
I do see a lot of happy reports of FR open baffle speakers around the Web, but I've not been able to make one that pleased me.
I do see a lot of happy reports of FR open baffle speakers around the Web, but I've not been able to make one that pleased me.
You can try the tweeter in same polarity as the woofer, it will work OK. But reverse polarity works better.
Well I just read through the whole thing, which is NOT to claim that I get it all. Two things seem unanswered: is the baffle width + wing depth effectively the same as a wider baffle? And why does the floor bounce issue go away with the big one? Also, has anyone tried planting a bucking magnet on a woofer but with the poles flipped to reduce Qt? Or do I have to get off my (old) butt and figure this stuff out for myself??
After many years and types of experiments I would like to give you proposal to get the best results from any OB. There are few laws, if you wish to get two main goals, good bass and pinpoint vocals:
- Stiffness of front plate is vital, the best results you will get from granite plate, in case of wood you will be able to go on, from wood plate final SPL, then became a high level of ringing, much louder than speakers produced, impossible to hearing
- woofer have to be between 15-18" and low resonance for good results. Unfortunately there is obligate to shelving bass from 50 down to resonance (28Hz) for linear bass, about 12dB. You cannot push woofer higher than 100Hz in any case, this job for mid
- mid have to be about 170mm, never smaller or wider and have to go down to 100Hz in low region without resonance. To push the mid higher is nonsense and bad for vocals
- tweeter have to be dome type and about 25-34mm and have to go under 1500Hz without resonance
- Driving the speakers have to be absolute via active crossover, cuts are 100/1500 if possible 24dB. DSP is cheaper and simpler, but far more heavy to hearing, the best is analog type
- There is no need to have all six amplifiers ultra high level quality, but stable, linear and the same gain.
I respect your critical stand, but there is nothing else but following right theory, independent of type of loudspeakers. You freely use cheap Chinese amps and low price drivers, your result will be 100x higher level like snake-oil nonsense. I finished mentioned construction with best of the best results, simple non comparable with anything. Yes, I used Audax TW34 tweeter, Audax 170mm mid and 18" woofer from Cervin Wega on hardwood. You freely use cheaper drivers; results will overcome anything, only the place is critical, you need some kind new wave wife, yes. I am offering self constructed analog crossover PCB (if need) for about 40$ per plate without material. I am not pushing anybody, you freely find any similar PCB (straight Elliott maybe?). Drivers you find at 100$ per pair (Monacor), which are not expensive (except place you need).
jozton, I'd be interested in learning how the principles you've outlined above translate into a DIY project. Perhaps you could share your plans. I'd prefer if you'd start a DIY SOTA open baffle speaker thread and leave this "Fast, fun inexpensive" thread to the Manzanita and other derivatives that live up to the billing.
Exotic Manzanita builds
As always, interesting to see what direction(s) things can go. Although some departures are a bit radical, can appreciate the journey and effort of others. But also realize we need to keep a broad focus on the initial goals even with the evolution of the Ultra and dual woofer variants. J
As always, interesting to see what direction(s) things can go. Although some departures are a bit radical, can appreciate the journey and effort of others. But also realize we need to keep a broad focus on the initial goals even with the evolution of the Ultra and dual woofer variants. J