Obviously he was talking about braces inside speaker boxes. That has no relevance in this thread.
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.
Any thoughts, or even better experiences, if placing OB speaker in a room like this can work, would be highly appreciated!
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.
Any thoughts, or even better experiences, if placing OB speaker in a room like this can work, would be highly appreciated!
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.
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.
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.
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.
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.
This latest version sounds tempting. I'm putting together what I need to purchase to try this out. But I'm confused by two items here and have another question or two. First there's a $7 price mentioned for the HF trap inductor, but that seems like a 4.7mH air core inductor and I don't think there has been a $7 inductor like that for many years. Do I have something wrong? The LF trap has a 0.4mH inductor and that is likely around the $7 mark. But that trap is gone from this version... Also, there's mention of a 0.1uF "by-pass" cap. Where in the world would we want a bypass cap like that, and how important is quality in that cap?
And two last things. I have a similar "low pass" crossover that crosses at 70Hz instead of 80. I think it's also 12dB. Would that work reasonably for a test build before I order parts for the final build? I may just try it but I can't quite imagine how much of a dip that might introduce and don't have the modeling skills to test it. And finally, I asked earlier about the Fountek FE85 (https://www.madisoundspeakerstore.com/approx-3-fullrange/fountek-fe85-3-aluminum-cone-full-range/) as a tweeter replacement (for the Peerless TC9FD18) but never heard a response. Again, I will almost certainly try it as I'm not worried about the lower power handling of the FE85. But there are some other differences (e.g. Qts, Vas, etc.) that I wonder about. I don't know much about speaker design so would love to hear any input on it.
Thank you all!
Hey Carl. Not sure about the inductor price, it might be a leftover from years ago, that price seems very low. The woofer trap was mostly used on the GRS woofer to clean up its top end. Usually not needed for the Peerless or for some other woofers. The 0.1 bypass cap would be in parallel with C1 the larger cap in series with the tweeter. It's just meant to give a little more top end to the tweeter, it's a subtle thing to experiment with.
By all means try your 70Hz crossover. 12dB might be too steep depending on a lot of factors such as the drivers, the baffle and the room. But if the crossover is just a simple coil and cap, you can lift one leg of the cap to make it a 6dB slope. Easy enough to try. Go for it with the FE85. You will almost certainly have to adjust the R1 resistor, but you should do that anyway with the stock design.
By all means try your 70Hz crossover. 12dB might be too steep depending on a lot of factors such as the drivers, the baffle and the room. But if the crossover is just a simple coil and cap, you can lift one leg of the cap to make it a 6dB slope. Easy enough to try. Go for it with the FE85. You will almost certainly have to adjust the R1 resistor, but you should do that anyway with the stock design.
John used to give me tips to try on his speakers when we were at the Lone Star Audio Fest.
Which, by the way, is next weekend in Dallas ...
One time he gave me grief for using an 18 gauge inductor on the 15" woofer trap. He basically demanded it get replaced with something in the neighborhood of 14 gauge. So when I got home I did just that and discovered once again that he was right.
He didn't seem at all bothered by the house brand partexpress caps. Never mentioned anything about them.
Another tip was to use the bypass caps. When I asked about the quality necessary for the bypass caps he just said to use the same cheap partsexpress caps that were already in the circuit. At the time those bypass caps were $1.
Didn't know what to make of his advice as most of what's on the web screams that the bypass has to be fancy. But I did what he told me and discovered, once again, that he was right.
Would a fancy cap have made a bigger difference? Don't know and never tried it. The Ultra was John's design so it seemed best to use his cookbook.
Which, by the way, is next weekend in Dallas ...
One time he gave me grief for using an 18 gauge inductor on the 15" woofer trap. He basically demanded it get replaced with something in the neighborhood of 14 gauge. So when I got home I did just that and discovered once again that he was right.
He didn't seem at all bothered by the house brand partexpress caps. Never mentioned anything about them.
Another tip was to use the bypass caps. When I asked about the quality necessary for the bypass caps he just said to use the same cheap partsexpress caps that were already in the circuit. At the time those bypass caps were $1.
Didn't know what to make of his advice as most of what's on the web screams that the bypass has to be fancy. But I did what he told me and discovered, once again, that he was right.
Would a fancy cap have made a bigger difference? Don't know and never tried it. The Ultra was John's design so it seemed best to use his cookbook.
Pano and Barry, thank you for this input. I'll try the FE85 and the 70Hz crossover (not a super simple design but I could probably lift the cap if I find a hole in the FR). Then again, the 80Hz unit John recommended is pretty dang cheap anyway so maybe I'll go ahead and get them. And for the bypass cap, I guess that position makes sense. I have some very nice but also some quite basic 0.1uF film caps to play with. In short, I will definitely be tweaking things and playing.
OK, one more thing. We have a soapstone countertop manufacturer in town who gives away scraps (up to 2'x4' or so) on occasion and I have a ton of it lying around. They say it's possible to work soapstone with woodworking tools but I haven't found that to be the case. It's hard to work with in my experience. But...would the stiffness and weight help at all? Should I give it a try? It's a lot of work so if there's no point, then...
