Pano pleaaaaaase !
I would expect something more by someone who is in the forum from 10+ years
an obstacle in the vicinity of a speaker's membrane causes DIFFRACTION
...someone might have tried it: see the famous BBC/ harbet examples.
Thin wall to sustain the speaker: yeah, a metal basket asks for it !
😡
I would expect something more by someone who is in the forum from 10+ years
an obstacle in the vicinity of a speaker's membrane causes DIFFRACTION
...someone might have tried it: see the famous BBC/ harbet examples.
Thin wall to sustain the speaker: yeah, a metal basket asks for it !
😡
Thought for the day
😕
I believe Strother Martin summed up the current situation in the following classic line from Cool Hand Luke:
"What we have here is a failure to communicate"
🙄
😕
I believe Strother Martin summed up the current situation in the following classic line from Cool Hand Luke:
"What we have here is a failure to communicate"
🙄
Ohhh yeah ! I must apologize !
Indeed, Pano's introduction in this thread is very thoughtful and precise, something that all the OB-lovers or OB-wannabe should read
That's why my disappointment comes from: he shouldn't be vague or imprecise, because he should know the answers for those simple questions.
What happens if a speaker is mounted from the rear of the baffle ?
Well, practically nothing if you don't mind the alterations produced by the diffraction phenomenon.
But...if the edges are rounded ? Well, you'll find some horn effect due to the etc etc.
Indeed, Pano's introduction in this thread is very thoughtful and precise, something that all the OB-lovers or OB-wannabe should read
That's why my disappointment comes from: he shouldn't be vague or imprecise, because he should know the answers for those simple questions.
What happens if a speaker is mounted from the rear of the baffle ?
Well, practically nothing if you don't mind the alterations produced by the diffraction phenomenon.
But...if the edges are rounded ? Well, you'll find some horn effect due to the etc etc.
Those answers are correct, given the limited information in the questions.
Also you have mis-quoted me a bit.
It has been clear in this thread since we started using the open back tweeter that you need to shape the back of the baffle to open up room for the driver to breath. Don't leave it stuck in a tunnel. Of course you don't want to rear mount the Vifa on a thick baffle, that just makes a tunnel in front of the driver. What may be harder to understand is that you can make a sub-baffle of thinner stock for the Vifa and mount that thin baffle in a hole cut into the main baffle. That can be easier, and often better, than cutting away around the back of the Vifa.
If your router skills are good enough and your baffle plywood strong, you can cut away a large opening from the back, leaving just enough thickness to mount the Vifa.
Using a thin enough sub-baffle, say 1/8" or 3/16" (somewhere around 3mm) then mounting the Vifa to the rear of that is possible. As to how much the diffraction from rear mounting is better or worse than the diffraction from the front mounted frame is going to be hard to determine. I doubt anyone here has done systematic tests. When front mounting with no inset, I like some felt around the tweeter.
Also you have mis-quoted me a bit.
It has been clear in this thread since we started using the open back tweeter that you need to shape the back of the baffle to open up room for the driver to breath. Don't leave it stuck in a tunnel. Of course you don't want to rear mount the Vifa on a thick baffle, that just makes a tunnel in front of the driver. What may be harder to understand is that you can make a sub-baffle of thinner stock for the Vifa and mount that thin baffle in a hole cut into the main baffle. That can be easier, and often better, than cutting away around the back of the Vifa.
If your router skills are good enough and your baffle plywood strong, you can cut away a large opening from the back, leaving just enough thickness to mount the Vifa.
Using a thin enough sub-baffle, say 1/8" or 3/16" (somewhere around 3mm) then mounting the Vifa to the rear of that is possible. As to how much the diffraction from rear mounting is better or worse than the diffraction from the front mounted frame is going to be hard to determine. I doubt anyone here has done systematic tests. When front mounting with no inset, I like some felt around the tweeter.
OK, let's try this...
How about beefing up the "sub frame" to allow a Pure Audio style "modular" solution, with the Vifa (Tymphany) in a thinner baffle and have that butted up against 3/4" thick baffle for the woofer and perhaps the top extent of the entire speaker? Of course done with an offset on the thin baffle to make up the difference, so the baffle face is as smooth a surface as possible.
Would this work? Due to prices of material it might actually lower the cost a bit more as well.
Given a full 3/4" thick baffle, would a half inch round over be sufficient to give the Vifa "breathing room" or does more material need to be removed for optimum results?
How about beefing up the "sub frame" to allow a Pure Audio style "modular" solution, with the Vifa (Tymphany) in a thinner baffle and have that butted up against 3/4" thick baffle for the woofer and perhaps the top extent of the entire speaker? Of course done with an offset on the thin baffle to make up the difference, so the baffle face is as smooth a surface as possible.
Would this work? Due to prices of material it might actually lower the cost a bit more as well.
Given a full 3/4" thick baffle, would a half inch round over be sufficient to give the Vifa "breathing room" or does more material need to be removed for optimum results?
I'll have to search the thread but I think there are some photos of the back cutaway done by some builders. It's more than 1/2", for sure.
Great thread! took me all weekend to read and take notes.
i'm in! The tymphany drivers are backordered. in January I will order and start building. Cant wait.
Very nice job John and Pano.
i'm in! The tymphany drivers are backordered. in January I will order and start building. Cant wait.
Very nice job John and Pano.
Thanks! Keep us up to date on your build. We love to see photos and hear about what you are doing. 
Quickly skimmed this tread because I wanted to catch up on what looks like a very good project. If someone would entertain my questions I'd appreciate it.
Q. Why has the Vifa PC9 replaced the original drivers used at the beginning of the thread?
Q. Is the GRS woofer used because it matches the efficiency of the Vifa?
Q. Where is the crossover between the woofer and full range driver?
Q. Why do most stand mount these rather than having them go all the way to the floor?
Q. Is the speaker usually paired with a powered sub or enjoyed without?
I built something similar but totally different. One thing for sure, I am a fan of open baffle using full range drivers and 15" woofers. I like the simplicity of a single baffle. Oceanw's project in post 1228 looks fantastic!
My project is here: https://speakerprojects.wordpress.com/2015/12/14/vifa-tc9-plus-helper-tweeter-on-open-baffle/
Q. Why has the Vifa PC9 replaced the original drivers used at the beginning of the thread?
Q. Is the GRS woofer used because it matches the efficiency of the Vifa?
Q. Where is the crossover between the woofer and full range driver?
Q. Why do most stand mount these rather than having them go all the way to the floor?
Q. Is the speaker usually paired with a powered sub or enjoyed without?
I built something similar but totally different. One thing for sure, I am a fan of open baffle using full range drivers and 15" woofers. I like the simplicity of a single baffle. Oceanw's project in post 1228 looks fantastic!
My project is here: https://speakerprojects.wordpress.com/2015/12/14/vifa-tc9-plus-helper-tweeter-on-open-baffle/
Attachments
Hey Godzilla, nice to see you over here on the Dark Side. 😛
Interesting H baffle O baffle thing you've go going there.
I will try to answer.
Interesting H baffle O baffle thing you've go going there.
I will try to answer.
Because the dome tweeter just could not play loud enough, low enough. A dome mid-tweeter was tried but the Vifa 3" turned out to be the magic bullet.
Not really. It is used because the Peerless woofer has gone up so much in price. The GRS is a very high value for dollar. They are surprisingly well made for the money. I got 4 of them delivered for $100! I built a twin 15" version.
Do you mean at what frequency? Acoustically about 900Hz, I think. It's 700 on mine, but my crossover and baffles are different.
A good question. You'd think the longer baffle would be better, but it isn't. The gap between floor and woofer helps to balance and smooth the bass response.
I've only ever heard it without. Doesn't seem to need one. Plays down into the 40s easily, sounds lower. It does not sound small.
I lately look at the other pair of GRS sitting at the corner doing nothing and I can't stop the itch to make them work. I'm living with the ultra for almost 2years and thought I should give all those drivers a chance to perform. Therefore the ultra plus comes to mind. John is not going to release his commercial to the public and I have to try it out as a kind of experiment and wish I could have good result in some sort. I did Google for crossover point and asked advices from forum members. I have the speakers up running and tweaking at the moment. I'm smiling when writing this message.
Attachments
Hallo all
Please Im interested in build of this project, but with maximum 12" (more probably10") woofer. I looked on this crossover http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-46.html#post2752617
in simulation software, and dividing frequency is about 500Hz, but on -15dB so frequency response of whole system is going very low around 500Hz. Excuse me Im beginner, but why is it?
Vish you all nice christmas
Best regards
Jan
Please Im interested in build of this project, but with maximum 12" (more probably10") woofer. I looked on this crossover http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-46.html#post2752617
in simulation software, and dividing frequency is about 500Hz, but on -15dB so frequency response of whole system is going very low around 500Hz. Excuse me Im beginner, but why is it?
Vish you all nice christmas
Best regards
Jan
Thanks for your responses Pano! Oh, I see albertli is here still building nice things.
I'm in a recycling mode these days taking inventory of what I have. Lately I've just been putting everything on an open baffle and plopping it on top of H-frames.
I'm in a recycling mode these days taking inventory of what I have. Lately I've just been putting everything on an open baffle and plopping it on top of H-frames.