200 Hz is the first floor reflection as a wide but shallow dip in the 6 dB/oct ramp. 500 Hz is the second floor reflection which is sharper because of the higher frequency. In between we have the dipole peak of the baffle.
Design for 8" driver
due to limited room space, I want to use smaller speaker say 8" Peerless P830869. It has a fs=30Hz, Qts=0.31. Will also use the Vifa 3.5" as tweeter. Please advise me the dimension of the panel and wings , and the crossover network ?? Or give me some guideslines of how to design. Thanks.
due to limited room space, I want to use smaller speaker say 8" Peerless P830869. It has a fs=30Hz, Qts=0.31. Will also use the Vifa 3.5" as tweeter. Please advise me the dimension of the panel and wings , and the crossover network ?? Or give me some guideslines of how to design. Thanks.
It can, if you do the low pass right. On a domestic sized OB the woofer will always have a rising response. To get the response you need, a lot of midrange needs to be thrown away. That's the OB trade-off. Starting with a more efficient driver, say one with a low Qt, you'll have to throw away more midrange, but you'll start with more overall level to throw away.
Kambule. John may weigh in otherwise, but I really don't think you will be happy with an 8" driver for OB. 12" or above is best. 8" can work well for OB miderange.
Kambule. John may weigh in otherwise, but I really don't think you will be happy with an 8" driver for OB. 12" or above is best. 8" can work well for OB miderange.
Ultra update
Here is an update on the Ultras.
For the first few months my Ultras really didn't sound like the ones John brought to the Lone Star Audio Fest a few years back. Mine were good sounding but there was a huge difference in the midrange. John's speakers had a rich tone and great texture in the midrange that my Ultras just didn't have. Truth be told mine sounded a bit bright.
I followed the plans correctly for size and layout and had ordered the correct parts. The only parts that were different from John's were the the capacitors and the wire. It didn't seem likely that either of those parts would account for such a big sonic difference. Some difference, yes, but not this much.
Long one short, it turns out it was my woodworking. There was a slight air gap at the bottom and top of each of the Vifa mid/tweeters. Small enough that it went unnoticed when the speakers were assembled but enough that if you stood at just the right angle you might see it. A small ring of rope caulk around the back of the drivers (next to the wood) sealed the gap and changed the tonality of the midrange.
Now they sound like they are supposed to sound.
I'm still playing with room placement and gear. One preamp has bass output that is massive when coupled with the Ultras but it's mid and highs are quite laid back. Played a bit with changing some of the Ultra crossover components to compensate and it gets pretty amazing. Sometime in the cold season I'll order more resistors to fine tune things even further.
Frankly, it's just brilliant to be able to tune the speaker to match the components and room instead of buying and selling components trying to find the right balance of sound. This preamp generally sounds too mellow with most speakers but a few resistor changes in the Ultra crossover changes things nicely.
One of the best things about the Ultras is that they are good speakers for everyday listening and for a wide variety of music. I've owned many speakers that are good for one type of music or certain recordings but fail on other genres. There are single driver speakers that are an example of that phenomenon ... truly great on certain things and completely miserable on others.
The Ultras hold pretty tight on most everything. I never shy away from putting something on because it would sound wrong and generally feel safe throwing anything at them. It's a well rounded design.
They are currently hooked up to a 120 watt solid state amp and get louder than I care to listen in a 19 x 22 foot room. I tend to play jazz and only rock out once in a while.
Going back to my (lack of) woodworking skills - I had planned to put a circle of black felt around the Vifa mid/tweeters to compensate for them not being surface mounted. This idea was suggested earlier in this thread to help smooth out the sound. The other benefit of the felt would be to make the Vifa appear much larger so it would visually balance out the big woofer. Basically it's a trick to make the little Vifa look bigger.
Well the felt circle did look better. But in my room/system it made the Ultras sound too laid back. Shame, it was a really good looking speaker with the felt ring. It's a good tweak if your room/system is more forward sounding.
For the money spent the Ultra is a pretty wonderful design. If you have the urge to tinker and have been considering a speaker project it's a very worthy undertaking.
Here is an update on the Ultras.
For the first few months my Ultras really didn't sound like the ones John brought to the Lone Star Audio Fest a few years back. Mine were good sounding but there was a huge difference in the midrange. John's speakers had a rich tone and great texture in the midrange that my Ultras just didn't have. Truth be told mine sounded a bit bright.
I followed the plans correctly for size and layout and had ordered the correct parts. The only parts that were different from John's were the the capacitors and the wire. It didn't seem likely that either of those parts would account for such a big sonic difference. Some difference, yes, but not this much.
Long one short, it turns out it was my woodworking. There was a slight air gap at the bottom and top of each of the Vifa mid/tweeters. Small enough that it went unnoticed when the speakers were assembled but enough that if you stood at just the right angle you might see it. A small ring of rope caulk around the back of the drivers (next to the wood) sealed the gap and changed the tonality of the midrange.
Now they sound like they are supposed to sound.
I'm still playing with room placement and gear. One preamp has bass output that is massive when coupled with the Ultras but it's mid and highs are quite laid back. Played a bit with changing some of the Ultra crossover components to compensate and it gets pretty amazing. Sometime in the cold season I'll order more resistors to fine tune things even further.
Frankly, it's just brilliant to be able to tune the speaker to match the components and room instead of buying and selling components trying to find the right balance of sound. This preamp generally sounds too mellow with most speakers but a few resistor changes in the Ultra crossover changes things nicely.
One of the best things about the Ultras is that they are good speakers for everyday listening and for a wide variety of music. I've owned many speakers that are good for one type of music or certain recordings but fail on other genres. There are single driver speakers that are an example of that phenomenon ... truly great on certain things and completely miserable on others.
The Ultras hold pretty tight on most everything. I never shy away from putting something on because it would sound wrong and generally feel safe throwing anything at them. It's a well rounded design.
They are currently hooked up to a 120 watt solid state amp and get louder than I care to listen in a 19 x 22 foot room. I tend to play jazz and only rock out once in a while.
Going back to my (lack of) woodworking skills - I had planned to put a circle of black felt around the Vifa mid/tweeters to compensate for them not being surface mounted. This idea was suggested earlier in this thread to help smooth out the sound. The other benefit of the felt would be to make the Vifa appear much larger so it would visually balance out the big woofer. Basically it's a trick to make the little Vifa look bigger.
Well the felt circle did look better. But in my room/system it made the Ultras sound too laid back. Shame, it was a really good looking speaker with the felt ring. It's a good tweak if your room/system is more forward sounding.
For the money spent the Ultra is a pretty wonderful design. If you have the urge to tinker and have been considering a speaker project it's a very worthy undertaking.
Thanks for the glowing report! Glad that you got them working with just a little caulk. 
Yes, tuning the speaker to the room is important, maybe even more so when sound comes out of both sides.
I think that many people are afraid to build this speaker because it's big and slightly weird. But the payoff is well worth it.
Yes, tuning the speaker to the room is important, maybe even more so when sound comes out of both sides.
I think that many people are afraid to build this speaker because it's big and slightly weird. But the payoff is well worth it.
It is a big speaker. It puts out bass. People ask if the subwoofer inbetween the two speakers is on. It is not.
I've got a question regarding the back finish of the Ultras.
One set of open baffle drivers I've owned sounded better with the back of their baffles covered in felt. My Ultras currently have nothing on the back of the plywood and I've considered covering them with felt.
So as a test I took a couple of paper towels and taped them around the back of the baffle near the Vifa. It was a clear improvement in clarity and focus. With that modest improvement it seemed logical to keep experimenting so I put a few more paper towels on the back of the baffle. It was clearly a bad move as the additional surface cover was just too mellow sounding. So no felt.
Somewhere in this thread it was mentioned using truck bed liner on the back of the manzi/ultra speakers. I'm assuming it will not mellow the speakers out like felt but don't really know how it will change things. And unlike the paper towel trick the truck bed liner is neither quick or reversible.
So before I do something that I'll regret, what does the liner do to the sound? Is it sonic or just to give the build a nice finished appearance?
I've got a question regarding the back finish of the Ultras.
One set of open baffle drivers I've owned sounded better with the back of their baffles covered in felt. My Ultras currently have nothing on the back of the plywood and I've considered covering them with felt.
So as a test I took a couple of paper towels and taped them around the back of the baffle near the Vifa. It was a clear improvement in clarity and focus. With that modest improvement it seemed logical to keep experimenting so I put a few more paper towels on the back of the baffle. It was clearly a bad move as the additional surface cover was just too mellow sounding. So no felt.
Somewhere in this thread it was mentioned using truck bed liner on the back of the manzi/ultra speakers. I'm assuming it will not mellow the speakers out like felt but don't really know how it will change things. And unlike the paper towel trick the truck bed liner is neither quick or reversible.
So before I do something that I'll regret, what does the liner do to the sound? Is it sonic or just to give the build a nice finished appearance?
Cheeky I know, but any chance of another update and summary - a further three years on and after more than 1,100 posts?
I would appreciate some sort of a current state of the Manzanita post. I am confused between all the mods and tweaks and all of this talk of the Ultra.
I have been getting an itch to finally put together a pair after thinking about it for the last 3 years.
Thanks for all the effort you guys have put into this open source project!
I have been getting an itch to finally put together a pair after thinking about it for the last 3 years.
Thanks for all the effort you guys have put into this open source project!
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John or Pano are responsible for the design and the thread but these are the links I've bookmarked. If they aren't the most current please post a correction!
This is the message that has the current Manzanita specs.
Fast, fun, Inexpensive OB project - Page 46 - diyAudio
Here is the message with the current Ultra crossover specs (the crossover schematic is two messages down).
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-86.html#post3438681
Here is the Ultra baffle.
The best affordable DIY open baffle loudspeaker I've listened to so far.
This is the message that has the current Manzanita specs.
Fast, fun, Inexpensive OB project - Page 46 - diyAudio
Here is the message with the current Ultra crossover specs (the crossover schematic is two messages down).
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-86.html#post3438681
Here is the Ultra baffle.
The best affordable DIY open baffle loudspeaker I've listened to so far.
I've been following this thread from time to time and got SO interested that I've purchased the parts and would like to experiment a little bit with the design. Will report back on that later.
But first some very general questions. they might have been answered before, but there's so much to read, I haven't read all posts...
- I like to countersink the drivers for aesthetical reasons. The Peerless will only get recessed by 1 mm or so, given the design of the mounting frame. The Vifa's however have a 4,5mm thick plastic plate that would then get countersunk. This means the distance to the baffle (depth wise) could be different than intended. Would that influence sound in a negative way?
- The rear cut-out for the Vifa's: I've seen several times a bigger coutnersink hole with straight edges. But would a 45 degrees side wall do the same trick (again for aesthetical reasons)?
But first some very general questions. they might have been answered before, but there's so much to read, I haven't read all posts...
- I like to countersink the drivers for aesthetical reasons. The Peerless will only get recessed by 1 mm or so, given the design of the mounting frame. The Vifa's however have a 4,5mm thick plastic plate that would then get countersunk. This means the distance to the baffle (depth wise) could be different than intended. Would that influence sound in a negative way?
- The rear cut-out for the Vifa's: I've seen several times a bigger coutnersink hole with straight edges. But would a 45 degrees side wall do the same trick (again for aesthetical reasons)?
Synergy.
When the Ultras first went together they only had a few screws holding them together and they had small gaps around the 3 1/2" fullrange driver. The drivers got burned in with a small TPA3116 chip amp and they sounded really good with small scale stuff like jazz trios or quartets. It was quite lovely.
Fast forward to yesterday. The Ultras are now screwed together with lots of screws and a huge quanity of glue. The gap around the full range driver has been patched. The TPA3116 got put back into the system ... and the magic just ain't there no more.
Odd hobby, this.
When the Ultras first went together they only had a few screws holding them together and they had small gaps around the 3 1/2" fullrange driver. The drivers got burned in with a small TPA3116 chip amp and they sounded really good with small scale stuff like jazz trios or quartets. It was quite lovely.
Fast forward to yesterday. The Ultras are now screwed together with lots of screws and a huge quanity of glue. The gap around the full range driver has been patched. The TPA3116 got put back into the system ... and the magic just ain't there no more.
Odd hobby, this.
Sorry for the late follow up!
Barry... OK... we need to figure out what has changed... your Ultra should sound better now that you have completed it. Has there been any improvement since your post in late November? I have been having some difficulties with this site recently, but it looks like Pano has the problem solved.
I have not heard from anyone else with a similar experience... Assume you have rechecked the crossover wiring for shorts and so forth. Also assume both channels sound the same. If you can, please describe what the difference is between past and present. Want you happy again!! John
Barry... OK... we need to figure out what has changed... your Ultra should sound better now that you have completed it. Has there been any improvement since your post in late November? I have been having some difficulties with this site recently, but it looks like Pano has the problem solved.
I have not heard from anyone else with a similar experience... Assume you have rechecked the crossover wiring for shorts and so forth. Also assume both channels sound the same. If you can, please describe what the difference is between past and present. Want you happy again!! John
Hi John,
There is nothing wrong with the Ultras. Quite the contrary, they keep getting better.
Earlier in this thread I commented there seemed to be a good synergy with the TPA3116 amp. That was when there was a small air gap around the Vifa due to my modest attempts at woodworking.
My last post was just me doing some housekeeping to let others know the earlier synergy wasn't there anymore with that particular amp. It obviously wasn't worded correctly. Sorry.
I'm really pleased with the Ultras and have spent a lot of time tweaking the system and have improved a lot of the gear, all of which can easily be heard. The system continues to sound better and better.
It's quite lovely sounding right now and I've purposely not posted more raves for fear of sounding like a lunatic.
Currently there is a conrad-johnson tube preamp in the system with a pair of Marantz ma-500 monoblocks. A nice tube pre to compensate for a somewhat sterile set of amps. It sounds great and far better than it should given the amps.
The amps aren't the last word in fidelity and were unable to drive an older pair of current hungry speakers with any sort of bass control. Those speakers needed pretty massive current solid state monsters to come alive. Yet the Marantz amps do well with the Ultras both in the quantity of bass and control of the woofers.
Sorry for the mix up. The speakers are damn fine.
There is nothing wrong with the Ultras. Quite the contrary, they keep getting better.
Earlier in this thread I commented there seemed to be a good synergy with the TPA3116 amp. That was when there was a small air gap around the Vifa due to my modest attempts at woodworking.
My last post was just me doing some housekeeping to let others know the earlier synergy wasn't there anymore with that particular amp. It obviously wasn't worded correctly. Sorry.
I'm really pleased with the Ultras and have spent a lot of time tweaking the system and have improved a lot of the gear, all of which can easily be heard. The system continues to sound better and better.
It's quite lovely sounding right now and I've purposely not posted more raves for fear of sounding like a lunatic.
Currently there is a conrad-johnson tube preamp in the system with a pair of Marantz ma-500 monoblocks. A nice tube pre to compensate for a somewhat sterile set of amps. It sounds great and far better than it should given the amps.
The amps aren't the last word in fidelity and were unable to drive an older pair of current hungry speakers with any sort of bass control. Those speakers needed pretty massive current solid state monsters to come alive. Yet the Marantz amps do well with the Ultras both in the quantity of bass and control of the woofers.
Sorry for the mix up. The speakers are damn fine.