Joztom a lot of what you say is either incorrect or not relevant to this particular project. In particular the damping factor stuff is wrong. The damping factor is determined by the ratio of the impedance of the speaker to all of the DC resistance in circuit including the output Z of the amplifier. This includes the cable and crossover inductor for example. This limits it typically to maybe 10 to 20. It is not a figure of merit.
In the market or Ebay you freely find many capable power amplifiers or do it yourself with apropriate PCB plan to work with such as very big and hard loudspeakers. If you look into the specifications of my very old amplifier Phase Linear 400 II, sometimes I used it for tests, you will find:
Power output: 210 watts per channel into 8Ω (stereo)
Frequency response: 20Hz to 20kHz
Total harmonic distortion: 0.25%
Damping factor: 1000
Input sensitivity: 1.7V
Signal to noise ratio: 100dB
I open say, testing with friend's wrong reconed AR3 gave brilliant result vs. slow amplifier and with low DF. In a lack of knowledge in electronic you are not possible to compensate bad solutions. In our case we are talking about two drivers in parallel??
I was invited to elaborate and fix this your project with two woofers and full range (Lowther) up driver, which are connected to FirstOne amplifier (Output impedance 20 Hz-20 kHz < 10 mOhm; Damping factor at 100 Wrms/4 Ohm, 20 kHz > 2000, measured on PCB output terminals, very good and capable. After direct connecting one woofer only with separate amplifier via active x-over and cut 100Hz with shelf (Linkwitz type), full range driver on separate amplifier from 100-1500 Hz, then we add tweeter (Dynaudio D28AF, capable to go down to 1500Hz without resonance) provisory on the rand of OB with clamp and also on separate amplifier for 1500Hz and up, we became heaven’s good sound and 3D space. With both woofers will be result much better, I think. Construction of mentioned OB is exact like yours, but owner is specialist for granite thumbs and finished it from very nice black granite. Result was more than excellent. Last 10 years I am doing on my personal OB with 18˝ CervinVega, 3-way and active driven and in term of this compared, I was invited for mentioned test. I open say, I will go to granite too in term more than excellent sound, which are not limited on SPL with wooden construction.
Power output: 210 watts per channel into 8Ω (stereo)
Frequency response: 20Hz to 20kHz
Total harmonic distortion: 0.25%
Damping factor: 1000
Input sensitivity: 1.7V
Signal to noise ratio: 100dB
I open say, testing with friend's wrong reconed AR3 gave brilliant result vs. slow amplifier and with low DF. In a lack of knowledge in electronic you are not possible to compensate bad solutions. In our case we are talking about two drivers in parallel??
I was invited to elaborate and fix this your project with two woofers and full range (Lowther) up driver, which are connected to FirstOne amplifier (Output impedance 20 Hz-20 kHz < 10 mOhm; Damping factor at 100 Wrms/4 Ohm, 20 kHz > 2000, measured on PCB output terminals, very good and capable. After direct connecting one woofer only with separate amplifier via active x-over and cut 100Hz with shelf (Linkwitz type), full range driver on separate amplifier from 100-1500 Hz, then we add tweeter (Dynaudio D28AF, capable to go down to 1500Hz without resonance) provisory on the rand of OB with clamp and also on separate amplifier for 1500Hz and up, we became heaven’s good sound and 3D space. With both woofers will be result much better, I think. Construction of mentioned OB is exact like yours, but owner is specialist for granite thumbs and finished it from very nice black granite. Result was more than excellent. Last 10 years I am doing on my personal OB with 18˝ CervinVega, 3-way and active driven and in term of this compared, I was invited for mentioned test. I open say, I will go to granite too in term more than excellent sound, which are not limited on SPL with wooden construction.
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Hi Joztom,
Please keep in mind the Manzanita and the Ultra aren't meant to be the ultimate open baffle speakers. They were designed to be cheap, easily constructed by beginners and very good sounding. A great place for somebody to get their feet wet in DIY/maker audio.
Are there better open baffles? Sure. John has been designing speakers for decades and has many outstanding speakers. He's been showing them at the Lone Star Audio Fest in Dallas for many years and has one of the best sounding rooms of the show.
But he sells those models so the specific details of construction and crossover design are not made public. The Manzi and Ultra are the freebies.
As for the freebies, build them according to the plans, keep them at least 3 or 4 feet away from the walls and feed them 75 to 100 good sounding watts and they'll sing.
Killer bass, too.
Barry
Please keep in mind the Manzanita and the Ultra aren't meant to be the ultimate open baffle speakers. They were designed to be cheap, easily constructed by beginners and very good sounding. A great place for somebody to get their feet wet in DIY/maker audio.
Are there better open baffles? Sure. John has been designing speakers for decades and has many outstanding speakers. He's been showing them at the Lone Star Audio Fest in Dallas for many years and has one of the best sounding rooms of the show.
But he sells those models so the specific details of construction and crossover design are not made public. The Manzi and Ultra are the freebies.
As for the freebies, build them according to the plans, keep them at least 3 or 4 feet away from the walls and feed them 75 to 100 good sounding watts and they'll sing.
Killer bass, too.
Barry
What is the latest revision of the crossover components?
I just stumble on this site today and am exited about the "Ultra" OB design.
We are having a speaker building contest at work where we can't exceed $200 for the drivers and I just happen to have ordered some of the GRS 15PF-8 15" used in the Ultra build here before I knew about this design.
Then I ran into this system build, which just by chance uses TC9FD-18-08s which I have (4) of and also (1) of the NE123W-08 drivers mentioned as an upgrade . Either of the driver options will allow me to meet the sub $200 goal.
I was going to order the crossover components but ran into significant discrepancies in the crossover components.
It seems like there is two versions out there, can some one verify which is the current?
Woofer Low Pass Inductor: 16 or 20 Mh?
Vifa High Pass Capacitor: 6.2 uf or 6.0?
Vifa Attenuation Resistor: 8 ohm?
Vifa Trap Inductor: 2.0 or 2.7 Mh?
Vifa Trap Resistor: 4.7 or 15 ohm?
I have a couple of other crossover questions:
*Is the optional woofer trap, (“coil - cap 15 uf & 0.40 mh in parallel with each other”), wired in series with the original 16 or 20 MH inductor or does it replace it?
*Other than changing the full range driver's "Attenuation Resistor" is there any other changes needed to the crossover to make the NE123W-08 driver work?
Thank you,
Darren
I just stumble on this site today and am exited about the "Ultra" OB design.
We are having a speaker building contest at work where we can't exceed $200 for the drivers and I just happen to have ordered some of the GRS 15PF-8 15" used in the Ultra build here before I knew about this design.
Then I ran into this system build, which just by chance uses TC9FD-18-08s which I have (4) of and also (1) of the NE123W-08 drivers mentioned as an upgrade . Either of the driver options will allow me to meet the sub $200 goal.
I was going to order the crossover components but ran into significant discrepancies in the crossover components.
It seems like there is two versions out there, can some one verify which is the current? Woofer Low Pass Inductor: 16 or 20 Mh?
Vifa High Pass Capacitor: 6.2 uf or 6.0?
Vifa Attenuation Resistor: 8 ohm?
Vifa Trap Inductor: 2.0 or 2.7 Mh?
Vifa Trap Resistor: 4.7 or 15 ohm?
I have a couple of other crossover questions:
*Is the optional woofer trap, (“coil - cap 15 uf & 0.40 mh in parallel with each other”), wired in series with the original 16 or 20 MH inductor or does it replace it?
*Other than changing the full range driver's "Attenuation Resistor" is there any other changes needed to the crossover to make the NE123W-08 driver work?
Thank you,
Darren
18-20mH iron core works best. Large gauge wire.
It won't make a huge difference either way.
That's a starting point. Adjust to your room and ears.
Maybe John can answer that.
In series with the low pass inductor.
Hello.... will review my notes... built so many versions, Talking about the woofer trap..IIRC, the 15 uf cap & parallel 0.4 mh inductor are wired in series with the large 16-22 mh low pass inductor. As Pano stated, for most, a 18-20 mh low pass is a good compromise. As for the Vifa trap... a good compromise is 2.5 uh inductor and 12 or 15 ohms based on your personal sonic discretion.
Pano, John, thank you both for the quick response!
John, thank for sharing your design with us. Although by coincidence I had all the drivers that were needed I would have absolutely been lost on the crossover. I takes real talent to take these very average components and make them work as well as you have.
Looking forward to building and listening to these speakers!
John, thank for sharing your design with us. Although by coincidence I had all the drivers that were needed I would have absolutely been lost on the crossover. I takes real talent to take these very average components and make them work as well as you have.
Looking forward to building and listening to these speakers!
Were you posting about the GRS being in stock at Sound Imports? It probably bears repeating for people in Europe wanting to build.
Buying a GRS 15PF-8 woofer? | SoundImports - SoundImports
Buying a GRS 15PF-8 woofer? | SoundImports - SoundImports
Hello Tyimo... Your intended plan looks interesting. However, without a lot of detailed information, and I mean A LOT, it is not possible to suggest a viable crossover. What you are planning, other than a similar baffle size is a totally different (new) speaker.
There are some useful hints and tips scattered throughout the tread that maybe helpful. Wish I had better news for you. If you do attempt your build, it would be interesting to hear from you here as to what you learn along the way. John
There are some useful hints and tips scattered throughout the tread that maybe helpful. Wish I had better news for you. If you do attempt your build, it would be interesting to hear from you here as to what you learn along the way. John
A "Very" general OB design approach
OK Tyimo: As has been posted before, you need to make a few design decisions before you buy or start anything. You have made one important decision with an approximate baffle size. Then active or passive crossover (Or a possible combination of the two). Low frequency cut off. Maximum required output. And of course, how much time and money you can afford to spend. You want to avoid creating a moving target design. Chasing your tail is NOT fun!
Assume you have read Troels Gravesen's articles on his approach on basic OB design here:
DIY-Loudspeakers
And Linkwitz here:
Electro-acoustic models
John
OK Tyimo: As has been posted before, you need to make a few design decisions before you buy or start anything. You have made one important decision with an approximate baffle size. Then active or passive crossover (Or a possible combination of the two). Low frequency cut off. Maximum required output. And of course, how much time and money you can afford to spend. You want to avoid creating a moving target design. Chasing your tail is NOT fun!
Assume you have read Troels Gravesen's articles on his approach on basic OB design here:
DIY-Loudspeakers
And Linkwitz here:
Electro-acoustic models
John