In case someones' planning on kick-starting a >=100w amp thread capable of meeting the power requirements for JB's vifa OB plus headroom - count me in. Having recently evolved from a gainclone up to a LM4702 based 100watter (that somehow died on the path from the protoboard to the PCB) and the "whole new galaxy" of information pouring fourth from the later, plus considering John's repeated recommendation that the amp be on par with his OB.. the timing seems about right for a 100watt amp thread - nevermind interaction I'm not even close to that point yet. I have a 100W amp schematic (not my own) in mind for this project - but could definitely use a second opinion - Pano, anyone?
Getting back on track. What a great read. Took me 2 days to go over several years of solid research, work and application of concept. Now all I gotta do is come up with the cash to get the parts (shipping is deadly). In any case, two things caught my eye. Someone mentioned these speakers can't reach down to the (I assume 20-40hz region) for organ music and certain orchestral pieces - isn't this dependant on room size and raw power being fed to the speaker? Also, I'm "very" curious as to how these speakers image - I gather the soundstage is good. As far as I can tell there are two kinds of imaging. One is where you can locate the musicians in 3d holograhpic space.. the other is where you hear someone singing, that despite all the clarity can be dislocated in space and therefore not as realistic. Anybody care to comment?
Manzi bass extension
OK... The usable low end extension is around 38 Hz. There is a bit of a peak around or just below 50 Hz in most rooms, then a slow roll off of 3 db or so back to flat down to around 40 Hz (flat as referenced to the system mid band) then a rapid transition to 24 db per octave roll off below that. How it sounds and measures. This assumes 36" - 48" from the baffle face to the rear wall with the woofer center about 30 - 34" off the floor. The greater the distance from the rear wall the farther down the Manzi can reach down toward the 38 Hz limit. If you try to equalize to reach lower you will quickly run out of displacement. Just one of the realities with a 12" woofer on a 15" wide baffle with short wings up off the floor. Sitting down on the floor you can reach a bit deeper down, say 35 Hz but the system tonal balance with the current crossover will not be right. Up close only a couple of feet away the Peerless is quite loud all the way down to resonance. But once you get out to a typical 8-12' listening distance in a typical residential living room, you get the response I describe above.
As for imaging, I am a bit biased. I hope others who have built the Manzi chime in with their opinion(s) on that issue. If they do not, in a few days I will try to offer as balanced a description as I can. One thing I will say is that with the woofer up off the floor as noted above, the imaging performance is much improved relative to sitting on the floor.
OK... The usable low end extension is around 38 Hz. There is a bit of a peak around or just below 50 Hz in most rooms, then a slow roll off of 3 db or so back to flat down to around 40 Hz (flat as referenced to the system mid band) then a rapid transition to 24 db per octave roll off below that. How it sounds and measures. This assumes 36" - 48" from the baffle face to the rear wall with the woofer center about 30 - 34" off the floor. The greater the distance from the rear wall the farther down the Manzi can reach down toward the 38 Hz limit. If you try to equalize to reach lower you will quickly run out of displacement. Just one of the realities with a 12" woofer on a 15" wide baffle with short wings up off the floor. Sitting down on the floor you can reach a bit deeper down, say 35 Hz but the system tonal balance with the current crossover will not be right. Up close only a couple of feet away the Peerless is quite loud all the way down to resonance. But once you get out to a typical 8-12' listening distance in a typical residential living room, you get the response I describe above.
As for imaging, I am a bit biased. I hope others who have built the Manzi chime in with their opinion(s) on that issue. If they do not, in a few days I will try to offer as balanced a description as I can. One thing I will say is that with the woofer up off the floor as noted above, the imaging performance is much improved relative to sitting on the floor.
This will be around in a couple of months:
http://www.diyaudio.com/forums/solid-state/192431-diyab-amp-class-ab-amp-diyaudio.html
and:
"Papa" Pass has just given us instructions on how to make a 100watt F-5
class A amp!!
http://www.diyaudio.com/forums/pass-labs/206240-f5-turbo-posted.html
http://www.firstwatt.com/pdf/art_f5_turbo.pdf
http://www.diyaudio.com/forums/pass-labs/206756-f5-turbo-circuit-boards.html
Ultra OB
Hi John, thanks for answering. I guess I'll just have to put the project together to find out firsthand what they sound like. One 'unusual' constant I'm finding regarding OB's is a tendency of OB builder's to not go back to box'ed enclosures.
Separately: I'm curious to know how the GRS 15PF-8 15" of the 'Ultra OB' compares to the Peerless? At a third of the price of the Peerless thats a deal maker for me. The best affordable DIY open baffle loudspeaker I've listened to so far.
Also.. about the "Erse super Q 20mH" in Pano's PE bom can't these be hand-wound? Do they have a steal core? Why so expensive?
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=266-960
Hi John, thanks for answering. I guess I'll just have to put the project together to find out firsthand what they sound like. One 'unusual' constant I'm finding regarding OB's is a tendency of OB builder's to not go back to box'ed enclosures.
Separately: I'm curious to know how the GRS 15PF-8 15" of the 'Ultra OB' compares to the Peerless? At a third of the price of the Peerless thats a deal maker for me. The best affordable DIY open baffle loudspeaker I've listened to so far.
Also.. about the "Erse super Q 20mH" in Pano's PE bom can't these be hand-wound? Do they have a steal core? Why so expensive?
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=266-960
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For anyone considering building the Manzanita's, I have a pair of mint condition Peerless 12" available:
http://www.diyaudio.com/forums/swap-meet/205828-fs-peerless-pi-bbe.html
http://www.diyaudio.com/forums/swap-meet/205828-fs-peerless-pi-bbe.html
For those who think 50 watts might be enough, take a look at the Fetzilla amp. It should cost between $200 and $250. I haven't heard a Manzanita, but I suspect this amp will do well for most people.
http://www.diyaudio.com/forums/aksa/191053-swordfishy-aspen-fetzilla-power-amp.html
http://www.diyaudio.com/forums/solid-state/186650-jfet-input-mosfet-vas-lateral-output-perfect.html
The third group buy is under way. I built my amp as part of group 2 and this amp is very good.
ray
http://www.diyaudio.com/forums/aksa/191053-swordfishy-aspen-fetzilla-power-amp.html
http://www.diyaudio.com/forums/solid-state/186650-jfet-input-mosfet-vas-lateral-output-perfect.html
The third group buy is under way. I built my amp as part of group 2 and this amp is very good.
ray
I had the same question. I am considering building one of these, and not sure which one.
Randy
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Oh yes.. indeedy doo
Hey Ray, thanks for the links.. that's exactly what I was looking for.
Hey Ray, thanks for the links.. that's exactly what I was looking for.
Manzanita vs. Ultra sonic impressions
OK, Manzanita and Ultra comparisons. Both offer a very flat frequency response and very good power response. The Manzanita has a bit more punch - dynamics, but does not reach as deep. The Ultra has very little roll off until the woofer resonance is reached (about 30 Hz.). Most of that is a combination of much higher woofer Q and a much larger baffle as compared to the Manzanita. The Manzanita will play louder (more woofer displacement). I personally find the Ultra to be a bit smoother in the midrange. The Ultra also seems to be a bit more revealing of amplifier quality. When driven at low to moderate levels with a good SET, SEP, or clean Class A tube push - pull amplification, the Ultra midrange performance can be amazing. And I rarely use the word "amazing" to describe a speakers characteristics. The Ultra is a couple of db more efficient, again a benefit from a large baffle. Both produce a wide and deep sound stage and surprisingly good instrument localization and are not way overblown as a lot of OB designs tend to be. When set up properly, and provided quality input, both of these designs can truly disappear. This was frequently commented on at LSAF relative to the Manzanita.
OK, Manzanita and Ultra comparisons. Both offer a very flat frequency response and very good power response. The Manzanita has a bit more punch - dynamics, but does not reach as deep. The Ultra has very little roll off until the woofer resonance is reached (about 30 Hz.). Most of that is a combination of much higher woofer Q and a much larger baffle as compared to the Manzanita. The Manzanita will play louder (more woofer displacement). I personally find the Ultra to be a bit smoother in the midrange. The Ultra also seems to be a bit more revealing of amplifier quality. When driven at low to moderate levels with a good SET, SEP, or clean Class A tube push - pull amplification, the Ultra midrange performance can be amazing. And I rarely use the word "amazing" to describe a speakers characteristics. The Ultra is a couple of db more efficient, again a benefit from a large baffle. Both produce a wide and deep sound stage and surprisingly good instrument localization and are not way overblown as a lot of OB designs tend to be. When set up properly, and provided quality input, both of these designs can truly disappear. This was frequently commented on at LSAF relative to the Manzanita.
Hi Pano,
I guess it was just a matter of time. I have a Vincent 331 amp that puts 150W into a 8ohm load. I used it with my newly built OB's without thinking about it. I measured each speaker at 6.5Ohms. That would be around 206 Watts. The speakers sound great with about 20 hours of use. Can I continue using this amp and what would be the high limit of power these can handle? Thank you.
Manzi power handling
At LSAF and here at home I often use my Musical Fidelity A308 which can deliver around 300 wpc into a 6 ohm load. Unless you really abuse the Manzi, it can handle your Vincent, MF A308 or similar. Just don't feed the Manzi clipped high power or extreamly low frequencies at high levels (U-571 depth charges) and you will be OK. The little Vifa can be damaged, but even if you trash it you can buy a new one for $10! Just use some common sense. As the Manzi approaches it's limits you will notice power compression and dimished dynamics. When that happens, time to back off a bit.
At LSAF and here at home I often use my Musical Fidelity A308 which can deliver around 300 wpc into a 6 ohm load. Unless you really abuse the Manzi, it can handle your Vincent, MF A308 or similar. Just don't feed the Manzi clipped high power or extreamly low frequencies at high levels (U-571 depth charges) and you will be OK. The little Vifa can be damaged, but even if you trash it you can buy a new one for $10! Just use some common sense. As the Manzi approaches it's limits you will notice power compression and dimished dynamics. When that happens, time to back off a bit.
Greetings, new comer, neat thread. First time speaker builder with a couple of questions, questions that would apply to either model. I Currently own an older set of Atma-Sphere 100w OTL mono amplifiers. Would these designs be compatable with this type of amplification? My second question is about listening levels. As the years pass, I've become much more aware of our internal hearing time clocks. Do these designs provide for musical depth at lower listening levels? ...Very attracted to boxless speakers.
Thank you.
Thank you.
manzanita build
Hi,
I've built manzanitas recently but never posted anything. They look different now, this was taken the very fist day after the build was completed. Sorry about the grainy picture; this was taken with my tablet.
Anyhow, the speakers works well and I am very happy with them. If anyone cares, I can post a more detailed write up.
Also, I'd like to thank the designers for such a well executed design.
Hi,
I've built manzanitas recently but never posted anything. They look different now, this was taken the very fist day after the build was completed. Sorry about the grainy picture; this was taken with my tablet.
Anyhow, the speakers works well and I am very happy with them. If anyone cares, I can post a more detailed write up.
Also, I'd like to thank the designers for such a well executed design.
Attachments
Manzanita Phase and impedance curves
Here is the WT3 phase and impedance data and curves for the current Manzanita. The impedance remains above 6.6 ohms and phase stays between +/- 45 deg. Should be an easy load. Have driven the Manzanita with SET, SET and class A push - pull with out any problems. Hope this helps. John
Here is the WT3 phase and impedance data and curves for the current Manzanita. The impedance remains above 6.6 ohms and phase stays between +/- 45 deg. Should be an easy load. Have driven the Manzanita with SET, SET and class A push - pull with out any problems. Hope this helps. John
Attachments
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