Yes, the Pluto sounds better as it lives in a larger room. When I moved the Pluto to my study room which is where the OB lives, the sound is not good at all. no bass.
I found it as paradox actually as Pluto was designed for smaller room but in fact in a very small one (3x4m) the dipole interact less with the room.
I found it as paradox actually as Pluto was designed for smaller room but in fact in a very small one (3x4m) the dipole interact less with the room.
Ooops ...
I meant that the other way around ... I preferred yours to the Plutos! Do the Plutos actually sound better in person? That 'live' recording sounds so much more dynamic - could be my speakers response.
Opinion regards HiVi's really appreciated, seeing using lower QTS mids as opening new doors.
Thanks - Bluto
I meant that the other way around ... I preferred yours to the Plutos! Do the Plutos actually sound better in person? That 'live' recording sounds so much more dynamic - could be my speakers response.
Opinion regards HiVi's really appreciated, seeing using lower QTS mids as opening new doors.
Thanks - Bluto
My thinking on the lower Qts drivers in OB:
Response rolloff going down is generally more gradual after driver resonance than with high Qts drivers
Using lower Qts drivers will generally broaden selection to include lower Fs, lower distortion, greater cosmetic appeal and generally higher quality all around
Active crossovers and multi-amping would be the best route to integrate drivers and maintain sound quality.
Having said that, I've been contemplating either the RS225S-8s or those 8" HiVis to be the helper woofers for my RS100S-8 fullrangers.
The primary downsides I'm contending with are:
With lower Qts drivers being rolled off further in the bass than high Qts ones, we need to use alot more power to level match them to the rest of the loudspeaker system, meaning that, even though lower Qts drivers tend to have greater power handling, Xmax, distortion characteristics, etc. it could be pretty easy to overdrive them to meet our needs, necessitating 2-4 drivers per side to be able to keep up in the bass with an effortless sound.
Lower Qts drivers tend to be higher priced, and if the first concern holds, then you can easily double or more the already higher price for drivers.
My $.02 for now. I'm in holding pattern waiting for some sort of budget to materialize to continue on. For now I'm dealing with higher Qts, paper Yamaha 8"ers for my bass.
Kensai
Response rolloff going down is generally more gradual after driver resonance than with high Qts drivers
Using lower Qts drivers will generally broaden selection to include lower Fs, lower distortion, greater cosmetic appeal and generally higher quality all around
Active crossovers and multi-amping would be the best route to integrate drivers and maintain sound quality.
Having said that, I've been contemplating either the RS225S-8s or those 8" HiVis to be the helper woofers for my RS100S-8 fullrangers.
The primary downsides I'm contending with are:
With lower Qts drivers being rolled off further in the bass than high Qts ones, we need to use alot more power to level match them to the rest of the loudspeaker system, meaning that, even though lower Qts drivers tend to have greater power handling, Xmax, distortion characteristics, etc. it could be pretty easy to overdrive them to meet our needs, necessitating 2-4 drivers per side to be able to keep up in the bass with an effortless sound.
Lower Qts drivers tend to be higher priced, and if the first concern holds, then you can easily double or more the already higher price for drivers.
My $.02 for now. I'm in holding pattern waiting for some sort of budget to materialize to continue on. For now I'm dealing with higher Qts, paper Yamaha 8"ers for my bass.
Kensai
Bluto said:
The dipole is magic when played loud. But I still have frustration that the dipole cannot have the vocal "fullness" of the pluto. It sounded thin by comparison. I did measurements and equalize as necessary. I wonder if this is the characteristic of OB or just missing some other eq.
If the dipole have the current bass, spatial etc. *and* pluto's female voice then the journey is "almost complete". I read too in SL's page that he had to revisit orion's design when hearing the pluto.
I'm a little bit confused here.Having been playing with fullrange OB and bass OB, I found the rolloff bass needs 'gain' but not actually 'power'. It seems a contradiction, but maybe not.Kensai said:
Mr. SL also mentioned on his web pages that it needs only very few power to reach the Xmax near fs, because on OB the woofers see air loads much less than other regular methods.
So, the system's limit is at the driver's displacement anyway, and we usually don't need very much power to reach it. Under this limit, all we need is extra 'gain' on bass to level the response.
I've used single digit watt SE tube amp for the OB bass with low Q drivers (Qts=0.29, fs=28Hz). And that's already too loud!
On the fullrage OB, I used even smaller amp with only 1w. It is able to push the 8"er fullrange to about 5~6mm p-p travel on some strong bass notes. And that's also quite loud in a small room.
Maybe someone can make measurements on the actual SPL / power input / diaphragm displacement for some OB setups (which I can not do myself). I think that'll be more persuasive than my previous comments.
Last edited by a moderator:
or maybe there isn't a constant sinusoidal signal at 20Hz eating up all the power. Amplifiers are capable of delivering higher transient power than RMS power. eg drum hits are quite transient.Originally posted by bigwill
To further this thought, the driver impedance is way up to around 50ohms
So maybe OBs aren't really as inefficient as people think
PS what happened to the "gallery"?
Last edited by a moderator:
y8s said:
Keep em coming
...This is by AV123
An externally hosted image should be here but it was not working when we last tested it.
AV123 is a goldmine. They even publish speakers under development.
av123.com is available for purchase - Sedo.com
I like the look and size of this mini hybrid OB:
av123.com is available for purchase - Sedo.com
I like the look and size of this mini hybrid OB:
An externally hosted image should be here but it was not working when we last tested it.
Last edited by a moderator:
Another Nelson Pass OB. Lowther + Seas 10" woofers
http://blog.stereophile.com/rmaf2007//index3.html
An externally hosted image should be here but it was not working when we last tested it.
http://blog.stereophile.com/rmaf2007//index3.html
Last edited by a moderator:
Greetings fellas, here are my ob's Ive been using for the last couple of years. B200 in baffle with a single vifa pushpull sub crossed at 180hz all made by my mate Nigel otherwise known as Mr Content.Sound fantastic, but I am going to have a play with the b200 + alpha 15 combo currently on Audiocircle just to see what difference when the entire range is ob.
keep em coming
peace and goodwill fergs
http://i30.tinypic.com/or3429.jpg
keep em coming
peace and goodwill fergs
http://i30.tinypic.com/or3429.jpg
Well, it's not an ultimate anything, but I just finished building the baffles for these speakers, and am now working on the crossovers. AE OB12, Audax PR170M0, BMS 4538/18Sound XT1086.
An externally hosted image should be here but it was not working when we last tested it.
Last edited by a moderator:
Thanks for the compliments. Yes, the baffles on the old speakers were pine, because I found these 16" edge-laminated pine panels and figured I wouldn't have to cut anything. That had the PR170M0 with a Fountek JP3.0 on top and a Peerless 850146 in the sealed cabinet below.
The new baffles are birch ply from Home Depot. I cut everything with a jigsaw, and didn't upload the pictures that showed how I glued them slightly crooked The stain is Minwax pre-stain conditioner, then Minwax mahogany gel stain, then I mixed in some cherry Polyshades on one coat of the stain, and then it's wipe-on poly on top. I really didn't know what I was doing, and luckily I had the good sense to stop before I tried one more coat and screwed everything up. I hung the baffles from the garage door opener tracks when I applied the stain. Some more photos:
They sound really good, but I have a lot of crossover work left. I'm fairly satisfied with the active crossover+EQ between the woofer and the midrange, it handles the dipole rolloff and peaks pretty well, so I was able to hit my target acoustic slopes with more or less textbook crossovers. I used LTSpice and Speaker Workshop to play with the component values and see what the filter's transfer function did to the drivers' responses.
The passive crossover between the midrange and tweeter - that's where there's work left. It's been a challenge for me to handle the ~4" acoustic offset difference, and the tweeter is further behind which is backwards from what it usually is. I have a design now that has the drivers more or less in phase, but the phase tracking around the crossover isn't very good. Anyway, it sounded good enough that I brought them into the living room and hooked them up to the stereo. I haven't had too much listening time on them yet, but I'll be tweaking the passive XO over the next few months. I haven't even done the final on-baffle measurements yet, I wanted to get these hooked up quickly so I would have music again.
This is copied from another forum post, but here's roughly what I was thinking when I came up with this 'design' (if you can call it that):
* I wanted to use that midrange because I had it in my previous speakers (the blonde baffles in the background) and like the way it sounds, and to keep the initial costs down
* I had a ribbon tweeter and never liked the integration, my midrange didn't go high enough and the tweeter didn't go low enough. So I wanted a new tweeter, wanted to try a compression driver, and decided to try for some level of 'constant directivity' in the front. So the baffle width was chosen to keep the midrange response dipole-ish up to a higher-than-usual frequency, and then the crossover to the tweeter is at roughly where the midrange's response starts to narrow. I eyeballed these with off-axis measurements, so it's largely handwaving, but that was the goal. On the low end, because of the narrow baffle, the midrange starts to roll off around 500Hz, which is where I cross to the woofer.
* I had the woofers in sealed cabinets in the old speakers, and wanted to try dipole woofers. This is where there seem to be two distinct schools of thought, and I went in the low-Qts/high-Xmax direction. We'll see how it works out. The woofer is pretty flat up to ~700Hz, so an LR4 XO at 4-500Hz works well. Because of that high XO, I didn't try a U or H frame, since any meaningful depth would add a resonance at a lower frequency.
So... hopefully I'll have a somewhat constant dispersion in the front from the bass up to the treble, and the back wave will start out dipole and then fade out at the mid-tweeter XO. I'll put that in the room and see how it sounds.
The new baffles are birch ply from Home Depot. I cut everything with a jigsaw, and didn't upload the pictures that showed how I glued them slightly crooked
The stain is Minwax pre-stain conditioner, then Minwax mahogany gel stain, then I mixed in some cherry Polyshades on one coat of the stain, and then it's wipe-on poly on top. I really didn't know what I was doing, and luckily I had the good sense to stop before I tried one more coat and screwed everything up. I hung the baffles from the garage door opener tracks when I applied the stain. Some more photos:They sound really good, but I have a lot of crossover work left. I'm fairly satisfied with the active crossover+EQ between the woofer and the midrange, it handles the dipole rolloff and peaks pretty well, so I was able to hit my target acoustic slopes with more or less textbook crossovers. I used LTSpice and Speaker Workshop to play with the component values and see what the filter's transfer function did to the drivers' responses.
The passive crossover between the midrange and tweeter - that's where there's work left. It's been a challenge for me to handle the ~4" acoustic offset difference, and the tweeter is further behind which is backwards from what it usually is. I have a design now that has the drivers more or less in phase, but the phase tracking around the crossover isn't very good. Anyway, it sounded good enough that I brought them into the living room and hooked them up to the stereo. I haven't had too much listening time on them yet, but I'll be tweaking the passive XO over the next few months. I haven't even done the final on-baffle measurements yet, I wanted to get these hooked up quickly so I would have music again.
This is copied from another forum post, but here's roughly what I was thinking when I came up with this 'design' (if you can call it that):
* I wanted to use that midrange because I had it in my previous speakers (the blonde baffles in the background) and like the way it sounds, and to keep the initial costs down
* I had a ribbon tweeter and never liked the integration, my midrange didn't go high enough and the tweeter didn't go low enough. So I wanted a new tweeter, wanted to try a compression driver, and decided to try for some level of 'constant directivity' in the front. So the baffle width was chosen to keep the midrange response dipole-ish up to a higher-than-usual frequency, and then the crossover to the tweeter is at roughly where the midrange's response starts to narrow. I eyeballed these with off-axis measurements, so it's largely handwaving, but that was the goal. On the low end, because of the narrow baffle, the midrange starts to roll off around 500Hz, which is where I cross to the woofer.
* I had the woofers in sealed cabinets in the old speakers, and wanted to try dipole woofers. This is where there seem to be two distinct schools of thought, and I went in the low-Qts/high-Xmax direction. We'll see how it works out. The woofer is pretty flat up to ~700Hz, so an LR4 XO at 4-500Hz works well. Because of that high XO, I didn't try a U or H frame, since any meaningful depth would add a resonance at a lower frequency.
So... hopefully I'll have a somewhat constant dispersion in the front from the bass up to the treble, and the back wave will start out dipole and then fade out at the mid-tweeter XO. I'll put that in the room and see how it sounds.
Last edited by a moderator:
