Ultimate OB GALLERY

[gainphile]

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.

[Bluto]

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

[Kensai]

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

[gainphile]

Originally posted by Bluto
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

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.

[CLS]

Originally posted by Kensai
...

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,...

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.

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.

[bigwill]

Originally posted by CLS

Having been playing with fullrange OB and bass OB, I found the rolloff bass needs 'gain' but not actually 'power'.

To further this thought, the driver impedance is way up to around 50ohms

So maybe OBs aren't really as inefficient as people think

[y8s]

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

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.

PS what happened to the "gallery"?

[gainphile]

Originally posted by y8s


PS what happened to the "gallery"?

Keep em coming ...

This is by AV123

[gainphile]

... this is a "wife pleaser" ...

[gainphile]

AV123 is a goldmine. They even publish speakers under development.

http://av123.com/component/option,co...,40/Itemid,37/

I like the look and size of this mini hybrid OB: