Pano, I can confirm that your hunch that the smaller inductor in combination with a parallel resistor on the Peerless provides better control of the low register is very true indeed. With the 20mH inductor alone there is some boominess around 50Hz which also masks details further upwards frequency wise. So, in my set up this is the better approach. It does, however, reduce the sensitivity some, which means that the padding resistor for the Vifa needs to be tweaked - how much I don't know as yet.
As for my listening room(s). One is app. 3*6 metres. Here I listen lengthwise with the speakers about 20 cm from the sidewalls - which shouldn't bother a dipole (with a figure of 8 dispersion pattern) too much. This room is quite damped acoustically due to shelves and furniture and a cork flooring. In this room the boominess around 50 Hz is quite pronounced - I haven't tried the 12mH inductor + parallel resistor in this room. The other is app. 4 * 7.5 metres, but here I have to listen across with the speakers some 80 cm (app. 30") from the back wall and about 1½ metres from the right sidewall and about 3 m from the left side wall. This room is fairly lively because there is a hardwood floor and less furniture and big windows. In this room the "boominess" with the 20mH inductor is less pronounced than in the other one, and it's almost gone with the 12mH/9R combination.
Hans Jørgen
As for my listening room(s). One is app. 3*6 metres. Here I listen lengthwise with the speakers about 20 cm from the sidewalls - which shouldn't bother a dipole (with a figure of 8 dispersion pattern) too much. This room is quite damped acoustically due to shelves and furniture and a cork flooring. In this room the boominess around 50 Hz is quite pronounced - I haven't tried the 12mH inductor + parallel resistor in this room. The other is app. 4 * 7.5 metres, but here I have to listen across with the speakers some 80 cm (app. 30") from the back wall and about 1½ metres from the right sidewall and about 3 m from the left side wall. This room is fairly lively because there is a hardwood floor and less furniture and big windows. In this room the "boominess" with the 20mH inductor is less pronounced than in the other one, and it's almost gone with the 12mH/9R combination.
Hans Jørgen
Hi,
Thanks for the comments. The place appeared to be a bit more cramped than I remembered, so I'm going with the original plan this time, the Vifa full range drivers coupled with a pair of smallish bandpass subs.
Hello everybody, I have just read the entire thread and I'm totally sold on these speakers 
I want to build Manzanitas Ultra, but the trouble I am having is in obtaining the GRS drivers at a price that won't defeat the "inexpensive" part of the project. I can see quite a few comments from European builders - guys, would you mind sharing your source of the 15-inchers?
I want to build Manzanitas Ultra, but the trouble I am having is in obtaining the GRS drivers at a price that won't defeat the "inexpensive" part of the project. I can see quite a few comments from European builders - guys, would you mind sharing your source of the 15-inchers?
Marinos... The design assumes the center of the Vifa be at the ear height of a typical seated listener.... 38"-42" approximately. This is what drives the stand height.
Klarskov... Most crossovers designs place the resistor just before or after the driver requiring attenuation. This is very important if one chooses to use an "L" pad arrangement (series and shunt). Some drivers benefit from a shunt arrangement from a damping stand point. The Vifa does just fine with a single series resistor, which does help keep the crossover parts count and layout as simple as possible. You can of course experiment with placement and value of the resistor. One of the nice things about this simple DIY design.
Klarskov... Most crossovers designs place the resistor just before or after the driver requiring attenuation. This is very important if one chooses to use an "L" pad arrangement (series and shunt). Some drivers benefit from a shunt arrangement from a damping stand point. The Vifa does just fine with a single series resistor, which does help keep the crossover parts count and layout as simple as possible. You can of course experiment with placement and value of the resistor. One of the nice things about this simple DIY design.
I gave up on the GRS and decided to go for the Peerless, which is widely available in Europe. So I have my drivers sorted, but I have another question:
My favourite crossover caps are not available in 6uF value - can I use 5.6uF instead, and compensate with a slightly smaller inductor (effectively shifting the crossover point up)? Or the other way round, bigger cap / bigger coil? 6.8uF is the nearest widely available value.
I understand a lot of this will come down to personal preference, but between these two deviations, is one of them preferable over the other?
My favourite crossover caps are not available in 6uF value - can I use 5.6uF instead, and compensate with a slightly smaller inductor (effectively shifting the crossover point up)? Or the other way round, bigger cap / bigger coil? 6.8uF is the nearest widely available value.
I understand a lot of this will come down to personal preference, but between these two deviations, is one of them preferable over the other?
I started with a 5.6µF and added more capacitance in parallel, so in my opinion your idea is just the way to go. It also makes it possible to increase the value by small increments at a time. By the way, at the moment I prefer around 7µF, but that may change.
I have also experimented quite a lot with he padding resistor - and it seems very very crucial. The over-all change brought about by a difference of just 1 -1½ ohm is clearly audible - and probably room-dependent.
I have also experimented quite a lot with he padding resistor - and it seems very very crucial. The over-all change brought about by a difference of just 1 -1½ ohm is clearly audible - and probably room-dependent.
This is nonsense: I mean that it is very critical!.
One more thing: As far as I understand the trap, the inductor determines when - frequency wise - it starts its thing whereas the capacitor determines the -6db frequency of the Vifa unit's response. So essentially they manipulate different parametres even though there is also some overlap in as much as both components affect the midrange too. But perhaps John and/or Pano can shed more light on it.
Yes... the trap, high pass cap, low end roll off induced by both the Vifa driver's native low end frequency response & open baffle roll off effects plus the pad all work together to shape the response of the Vifa. Simple.... but not so simple as is usually the case with a multi-way speaker. And you also have to consider the rear radiation frequency shaping (Roll off) of the Vifa magnet structure, basket and pole piece vent. The front and rear radiation are very different from the Vifa unlike the woofer where there is not much difference.
U.L. Varying the inductor between 18 & 22 UF has minimal effects on the upper roll off of the woofer assuming the inductors are all 15 ga iron core.
The real work is with the Vifa high pass cap, pad and trap shunt resistor. All I can recommend is to start with 5.0 UF and add inexpensive 0.33 UF or similar in parallel with the 5.0 up to about 6.5 UF and see how that works.
However, if you go below 5.0 or higher than 6.5 UF will likely need to adjust your pad. Could be 1/2 ohm or 1 ohm to retain the proper cross over frequency.
The real work is with the Vifa high pass cap, pad and trap shunt resistor. All I can recommend is to start with 5.0 UF and add inexpensive 0.33 UF or similar in parallel with the 5.0 up to about 6.5 UF and see how that works.
However, if you go below 5.0 or higher than 6.5 UF will likely need to adjust your pad. Could be 1/2 ohm or 1 ohm to retain the proper cross over frequency.
Hi
I have a question a little bit out of the scope here.
You have developed the Manzanitas with a square front baffle.
Are the any pros or cons against making the front baffle in a trapez shape?
I am not so much talking about the Manzanitas, but open baffle in general.
best regards
uwe
I have a question a little bit out of the scope here.
You have developed the Manzanitas with a square front baffle.
Are the any pros or cons against making the front baffle in a trapez shape?
I am not so much talking about the Manzanitas, but open baffle in general.
best regards
uwe
Last edited:
I am ready to build my first open baffle project, and based on what I have searched out, the Manzanita / Manzanita Ultra is a great place to start. I have read a majority of this thread, as well as the other threads I found via google, however I still have a few questions I was hoping someone could help me with.
- The crossover / design for the dual woofer version of the Ultra was never released? Has anyone tried to build one?
- As space and $$ are not huge concerns at these levels, the Ultra is the way to go vs the original 12" woofer design?
Thank you for your help!
- The crossover / design for the dual woofer version of the Ultra was never released? Has anyone tried to build one?
- As space and $$ are not huge concerns at these levels, the Ultra is the way to go vs the original 12" woofer design?
Thank you for your help!
"europeen crossover"
Ja- ccap-620 Jantzen Cross Cap MKP capacitor 6.2 uF / 400V
M- BL100-200 Mundorf Baked Varnish Luftspule BL100, 2.0 mH/0.74
M- bs140-220 Mundorf bs140 core coil 22mH/0.56Ohm
M- res20-047 MResist Supreme 4.7 Ohm / 20 Watt
M- res20-082 MResist Supreme 8.2 Ohm / 20 Watt
i can not judgen these elements are they correct?
Yours Bart
Ja- ccap-620 Jantzen Cross Cap MKP capacitor 6.2 uF / 400V
M- BL100-200 Mundorf Baked Varnish Luftspule BL100, 2.0 mH/0.74
M- bs140-220 Mundorf bs140 core coil 22mH/0.56Ohm
M- res20-047 MResist Supreme 4.7 Ohm / 20 Watt
M- res20-082 MResist Supreme 8.2 Ohm / 20 Watt
i can not judgen these elements are they correct?
Yours Bart
Pano, units have arrived and I can see what you mean about Peerless. Thanks for the information
About Vifa. Is it critical to flash mount it ? It is not that easy to route it's shape.. Also, there is a flange in front of the chassis. Perhaps for positioning the unit at the back of it's supporting surface. What did you do with that ?