Hi John, its as the crossover on #3 but I've got 3x 25R in parallel (i.e. 8.3R), actually it doesn't sound so bad like that.
http://www.michael.mardis.com/speaker/images/M12-crossover.gif
I plan to make some stands & then veneer everything & recess the tweeters... then get a L20D erm.. then try again
Manzanita with the TDFC
Hello Simon
Good to hear from you. I need to revist the original design. Have the parts, it's finding the time that has been a problem for me. One thing about the Manzinita design is that it is easy, and fairly inexpensive to experiment with. It is interesting you find a lower pad a better balance. No right or wrong with that, it's all good. The original values did produce a broad mid range dip. In a near field application with near field wall reflections the mid range did fill out enough to be considered usable by many.
The original design asks a lot of the TDFC. One of the compromises was to get out of the TDFC a bit sooner than a flat summed midrange response would normally indicate. And to keep the system simple and inexpensive. Any lower and you just tear up the TDFC. Also, the system was intended for low to moderate listening levels.
Bottom line is that if you feel a hotter tweeter is what you like, that's OK. Your taste, your speaker. Your listening room-conditions. One thing to keep in mind is that the pad is a series pad and by lowering the series resistance, you also change the crossover point to quite a degree. So you may want to buy some cheap one or two mfd caps and experiment varying the capacitor value - pad values to find the balance you feel is best.
Just keep in mind the TDFC can only play down to about 2K with a second order filter.
I hope to find some time and play with a TDFC set up. See what I can re-learn.
John
Hello Simon
Good to hear from you. I need to revist the original design. Have the parts, it's finding the time that has been a problem for me. One thing about the Manzinita design is that it is easy, and fairly inexpensive to experiment with. It is interesting you find a lower pad a better balance. No right or wrong with that, it's all good. The original values did produce a broad mid range dip. In a near field application with near field wall reflections the mid range did fill out enough to be considered usable by many.
The original design asks a lot of the TDFC. One of the compromises was to get out of the TDFC a bit sooner than a flat summed midrange response would normally indicate. And to keep the system simple and inexpensive. Any lower and you just tear up the TDFC. Also, the system was intended for low to moderate listening levels.
Bottom line is that if you feel a hotter tweeter is what you like, that's OK. Your taste, your speaker. Your listening room-conditions. One thing to keep in mind is that the pad is a series pad and by lowering the series resistance, you also change the crossover point to quite a degree. So you may want to buy some cheap one or two mfd caps and experiment varying the capacitor value - pad values to find the balance you feel is best.
Just keep in mind the TDFC can only play down to about 2K with a second order filter.
I hope to find some time and play with a TDFC set up. See what I can re-learn.
John
Thanks for the comments, John.
A floor standing version of the 12" could be done, but it won't sound as smooth or as open as the original version. If you do a floor length baffle, just be sure that the woofer is 32-36" above the floor. Otherwise floor bounce will kill it.
If the baffle is done full length, you'll have to tweak the crossover and maybe the wings for smoothest response. There is no real gain, other than ease of construction, and some real sonic trade-offs.
A floor standing version of the 12" could be done, but it won't sound as smooth or as open as the original version. If you do a floor length baffle, just be sure that the woofer is 32-36" above the floor. Otherwise floor bounce will kill it.
If the baffle is done full length, you'll have to tweak the crossover and maybe the wings for smoothest response. There is no real gain, other than ease of construction, and some real sonic trade-offs.
I done a floorstander version but 3 ways with one or two woofers.
A lot of work, 2 years to have the best compromise sound.
A lot of work, 2 years to have the best compromise sound.
One thing to consider is that the original design requires the Woofer to work well into the midrange. Most OB woofers are done around 300 Hz. After much experimentation the only way I could find that provided a good combination of tonal balance, power response, SIMPLE crossover and bass extention ended up being a stand mounted design.
A floor stander can work, but as Jerome notes, be prepaired to do a lot of work. You end up with a 2.5 way, or with a dedicated midrange, a 3.5 way. Tough enough in a box, really difficult in an OB.
A floor stander can work, but as Jerome notes, be prepaired to do a lot of work. You end up with a 2.5 way, or with a dedicated midrange, a 3.5 way. Tough enough in a box, really difficult in an OB.
Manzanita wall separation distances
Like all open baffles, distance from any large reflective surface is good.
You can run the Manzanita from about 24" or more from rear and side walls and obtain good results. As the distance to the rear wall diminishes, so does the low end extention and tonal balance.
One can spread the distance between the left and right speakers a bit and increase the angle of the baffle face relative to the rear wall and some what offset the loss of bass extention. You can go up to around a 45 degree angle and adjust your seating distance - position to make up the difference.
You can also increase the inductor a bit more to make up for the mid bass gain a close rear wall proximaty will provide.
Bottom line, using some trial positions you can usually find a reasonable compromise of bass extension, tonal balance and seating position.
Hope this helps.
John
Like all open baffles, distance from any large reflective surface is good.
You can run the Manzanita from about 24" or more from rear and side walls and obtain good results. As the distance to the rear wall diminishes, so does the low end extention and tonal balance.
One can spread the distance between the left and right speakers a bit and increase the angle of the baffle face relative to the rear wall and some what offset the loss of bass extention. You can go up to around a 45 degree angle and adjust your seating distance - position to make up the difference.
You can also increase the inductor a bit more to make up for the mid bass gain a close rear wall proximaty will provide.
Bottom line, using some trial positions you can usually find a reasonable compromise of bass extension, tonal balance and seating position.
Hope this helps.
John
More updated info on the current Manzanita project
There have been some changes and refinements in the Manzanita since it first appeared 4 years ago in this thread. Let's look at those changes and improvements and give you an updated map to a Fast, Fun Affordable OB speaker.
Some of the following information has been previously posted here, but thought it appropriate to consolidate all the latest information into a single comprehensive post.
First, the Drivers.
The excellent Peerless SLS 830669 - 12" Woofer has been retained and is the heart of the Manzanita speaker. The original tweeter has been dropped from the design and replaced with the very good Vifa TC9FD18-08, 3.5" Full Range doing upper mid/tweeter duties. Many drivers were tried; the Vifa 3.5" is a winner for sound quality, cost and integration with the design.
Second, the Baffle.
I've tweaked the baffle plate to 28" H X 15" W. The wings are now simpler and symmetrical at 28" H X 4.25" D and 0.70" thick mounted on the sides. You end up with a final assembled width of 16.4". The baffle is 3/4" birch ply as is the base plate. The base plate (foot) is full baffle width 15"W x 8"D. As with the original, the crossover is mounted on the base plate. For those who do not have a pickup truck or similar, you can buy 24" X 48" X 3/4" birch ply sheets from Home Depot, Lowes, etc. that will fit in most cars. BTW, the baffle H & W dimensions are not critical. Stay within an inch on the width & height you will be OK.
The baffle, wings and base plate are mounted together with simple pine 2" X 2" rear sub frame. (1.5" X 1.5" dimensional net) Once you are satisfied with your baffle assembly, a sheet rock screw and glue combo is highly recommended. The Peerless cone movement is considerable and anything not held tightly in position will rattle. This includes all of the crossover components too. Both drivers are mounted on the baffle front.
We need to integrate the rear radiation of the Vifa. The previous HF drivers were chambered and rear radiation was not an issue. When the Vifa TC9FD18-08 is mounted on a full 3/4" thick baffle, there is near zero rear open area. To correct for this and let the back of the Vifa breath, route a 4.5" diameter round counter sink on the REAR side of the baffle with a sink depth of 7/16". You now have a stepped hole for the Vifa, larger in back than in front. This opens up the back radiation considerably, is simple to do if you have a router and there is still enough baffle thickness remaining to secure the Vifa with small screws. You can visit the June 4th posts and see pictures of the front and rear of the prototype for reference. http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-41.html#post2595033
The Peerless woofer is centered left to right with the woofer center height 12" from the bottom of the baffle. The Vifa center is 21" from the baffle bottom and 5.25" from the (Left or right) baffle plate edge. (This distance does NOT include the wing edge thickness) One needs to observe left and right positioning with the Vifa. The offset is very important and provides a great deal of baffle diffraction smoothing. The Vifa's off center (offset) position also sets F equal and F peak frequencies (for the Vifa) and the crossover is designed around these values. If you center the Vifa, the crossover will not be right!
And Third:
What many have been waiting for, the new crossover. The Woofer is very simple as it uses a single inductor of 20mH. I recommend an Iron Core 15 or 16 gauge inductor. This inductor is connected in series with the Positive terminal of the Peerless woofer. That's all the woofer needs. The Vifa TC9FD18-08 (available from Madisound in the USA) requires 4 components to do its thing. A good quality 6 MFD high pass capacitor (Solen or better), a high quality 4.5 ohm, 5 watt pad resistor follow by a 2 element trap are used in series.
What really makes the Vifa behave is the trap. The trap controls the rising response the Vifa exhibits. Use a good air core 2.0 Mh (14-18 ga.) with a 8-10 ohm bypass resistor. Like the resistor and cap, the Inductor-resistor trap is placed in series with the positive terminal of the Vifa. Place the trap between the high pass cap and the positive terminal of the Vifa. You can vary the value of the pad and/or bypass resistor to tune the speaker to your room and your ears.
It will be interesting to get feedback from those who try the above solution In a later post I'll talk about tweaking the crossover to suite your room, your ears and your taste. But these values will get you started and 90% of the way there. After that, it's just fine tuning.
Pano will be posting updated dimensional drawings and crossover schematic reflecting the above later today. Thanks for the continuing interest in the Manzanita OB project!!
There have been some changes and refinements in the Manzanita since it first appeared 4 years ago in this thread. Let's look at those changes and improvements and give you an updated map to a Fast, Fun Affordable OB speaker.
Some of the following information has been previously posted here, but thought it appropriate to consolidate all the latest information into a single comprehensive post.
First, the Drivers.
The excellent Peerless SLS 830669 - 12" Woofer has been retained and is the heart of the Manzanita speaker. The original tweeter has been dropped from the design and replaced with the very good Vifa TC9FD18-08, 3.5" Full Range doing upper mid/tweeter duties. Many drivers were tried; the Vifa 3.5" is a winner for sound quality, cost and integration with the design.
Second, the Baffle.
I've tweaked the baffle plate to 28" H X 15" W. The wings are now simpler and symmetrical at 28" H X 4.25" D and 0.70" thick mounted on the sides. You end up with a final assembled width of 16.4". The baffle is 3/4" birch ply as is the base plate. The base plate (foot) is full baffle width 15"W x 8"D. As with the original, the crossover is mounted on the base plate. For those who do not have a pickup truck or similar, you can buy 24" X 48" X 3/4" birch ply sheets from Home Depot, Lowes, etc. that will fit in most cars. BTW, the baffle H & W dimensions are not critical. Stay within an inch on the width & height you will be OK.
The baffle, wings and base plate are mounted together with simple pine 2" X 2" rear sub frame. (1.5" X 1.5" dimensional net) Once you are satisfied with your baffle assembly, a sheet rock screw and glue combo is highly recommended. The Peerless cone movement is considerable and anything not held tightly in position will rattle. This includes all of the crossover components too. Both drivers are mounted on the baffle front.
We need to integrate the rear radiation of the Vifa. The previous HF drivers were chambered and rear radiation was not an issue. When the Vifa TC9FD18-08 is mounted on a full 3/4" thick baffle, there is near zero rear open area. To correct for this and let the back of the Vifa breath, route a 4.5" diameter round counter sink on the REAR side of the baffle with a sink depth of 7/16". You now have a stepped hole for the Vifa, larger in back than in front. This opens up the back radiation considerably, is simple to do if you have a router and there is still enough baffle thickness remaining to secure the Vifa with small screws. You can visit the June 4th posts and see pictures of the front and rear of the prototype for reference. http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-41.html#post2595033
The Peerless woofer is centered left to right with the woofer center height 12" from the bottom of the baffle. The Vifa center is 21" from the baffle bottom and 5.25" from the (Left or right) baffle plate edge. (This distance does NOT include the wing edge thickness) One needs to observe left and right positioning with the Vifa. The offset is very important and provides a great deal of baffle diffraction smoothing. The Vifa's off center (offset) position also sets F equal and F peak frequencies (for the Vifa) and the crossover is designed around these values. If you center the Vifa, the crossover will not be right!
And Third:
What many have been waiting for, the new crossover. The Woofer is very simple as it uses a single inductor of 20mH. I recommend an Iron Core 15 or 16 gauge inductor. This inductor is connected in series with the Positive terminal of the Peerless woofer. That's all the woofer needs. The Vifa TC9FD18-08 (available from Madisound in the USA) requires 4 components to do its thing. A good quality 6 MFD high pass capacitor (Solen or better), a high quality 4.5 ohm, 5 watt pad resistor follow by a 2 element trap are used in series.
What really makes the Vifa behave is the trap. The trap controls the rising response the Vifa exhibits. Use a good air core 2.0 Mh (14-18 ga.) with a 8-10 ohm bypass resistor. Like the resistor and cap, the Inductor-resistor trap is placed in series with the positive terminal of the Vifa. Place the trap between the high pass cap and the positive terminal of the Vifa. You can vary the value of the pad and/or bypass resistor to tune the speaker to your room and your ears.
It will be interesting to get feedback from those who try the above solution In a later post I'll talk about tweaking the crossover to suite your room, your ears and your taste. But these values will get you started and 90% of the way there. After that, it's just fine tuning.
Pano will be posting updated dimensional drawings and crossover schematic reflecting the above later today. Thanks for the continuing interest in the Manzanita OB project!!
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