So the Orange "Smart Power" Cab design never caught on?

[JimmyM]

I always think of isobaric cabs as twice the speakers with half the volume. It makes them quite difficult to fart out, but I don't play very loud anyway.

 

[Jeff Scott]

Basically, a terrible design choice by Orange.

 

[chris_b]

The design piggy-backs speakers within a cabinet, allowing for the sound of the second layer of speakers to come through the porting.

As I understand this (as a non technical person), you don't hear anything that comes out of the back of the first speaker or out of the front of the second speaker. Seems to me that's a whole speaker you've bought that you're not able to hear. What's the point or advantage in that? If what you hear coming out of the port is the back of the second speaker, how is that any different to hearing the back of the first speaker coming out of the port in a one speaker enclosure?

I would expect if you really want to hear the improvements that a second speaker brings then put two single speaker cabs together. An absolutely night and day improvement over one speaker and any isobaric design.

 

[HaphAsSard]

Wikipedia, the free encyclopedia

"Design principles" paragraph 2:

"The new efficiency is thus 3 dB lower than with one loudspeaker."

Two speakers, isobarically loaded and wired in parallel, while having deeper extension, will be quieter than a single identical driver with the same power.

I could be wrong, but that's how I'm interpreting it.

Thank you. Mine was an honest question: I believe it's always useful to look at things in detail instead of playing telephone, and I did start wondering about efficiency thanks to your first post. Oh, and I did guess which Wiki page you'd wanted to link regardless. No inline sources cited (this is not to say I detect any inaccuracy, but it would be useful to have sources handy for single points being made), and the last paragraph of the section in particular is a little too simplistic and could use a wee bit more encyclopedic style (reads like a TB post currently). But I digress.

B. Efficiency only tells you the loudness wrt to 1w. Ultimate loudness depends on how much power you can throw at it.

Yup. Sensitivity as it's commonly defined (XdB @ 1 metre and especially 1 watt) does appear to be 3dB down, which would make itself heard (less) with valve amps - for worse or better, if one enjoys valve power amp breakup, which depending on the power rating of the head could be easier to achieve with one of these Orange cabs; "voltage sensitivity" would instead be about the same with solid state amps.
On paper, at least.

I did a very quick and dirty test case in Win ISD. In that case I found dead equal sensitivity between 1 standard single driver vented build and one isobaric one at half the cab volume of the first one.

Am I wrong in interpreting that being the case because of WinISD's reliance on T/S parameters to calculate, among other things, sensitivity? I mean, isn't it reasonable that, beyond where cab design gradually stops playing a big part and (most) parameters cease to be of significance i.e. from the lower mids on up, the single driver cab should be 3dB louder than the iso, input wattage being equal, simply because it doesn't have to share the juice with the internal driver (which in turn isn't heard, midrange-wise, apart from some messing with the midrange response of its external twin)?

and max SPL shows as 3dB hotter for the single driver case.

Now this part I can't figure out the reason why. (The fact I'm a dunce has probably something to do with it.)

 

[bolophonic]

I am all about lightweight cabs, but who wants to lug around a 2x12" that doesn't even come up to your knee?

 

[HaphAsSard]

Of course they are not going to use same drivers for isobaric. They are going to use the low power requirement to their advantage in the construction to make it more like a guitar speaker I would guess. There has to be some advantage to less massive coil need.

That's an astute observation. You may well be right.
Older posts by @DukeLeJeune on this type of design also made me wonder if, and if so how, Orange has managed to minimise the further problem I've read about (and mentioned in passing in my post above), namely midrange interference between the inside and outside driver.
Is drivers literally facing one another a necessary and defining trait of the alignment, or could the direct view between the cones be obstructed by a diafragm (partially open on one or two sides to allow airflow)?

 

[klejst]

Different design concept and I'll give Orange that however I too heard from those who owned and used them they were really not that great of cabs.

 

[pie_man_25]

Thank you. Mine was an honest question: I believe it's always useful to look at things in detail instead of playing telephone, and I did start wondering about efficiency thanks to your first post. Oh, and I did guess which Wiki page you'd wanted to link regardless. No inline sources cited (this is not to say I detect any inaccuracy, but it would be useful to have sources handy for single points being made), and the last paragraph of the section in particular is a little too simplistic and could use a wee bit more encyclopedic style (reads like a TB post currently). But I digress.

Hey, fair enough, even to the other guy that flat out said I was wrong - I've been wrong before, and being corrected is a learning opportunity. I can absolutely agree that there are many better sources than Wikipedia on any topic, but I've found that often enough, even citing Wikipedia can leave you light years ahead in what passes for "debate" with most people.

Either way, it seems Passinwind has provided some interesting evidence to my contrary, and while I can't verify myself - it turns out I got the night back in civilization, but my laptop doesn't have winisd on it, or hornresp, and due to circumstances can't get to an internet connection to look into it better.

Anyways, I'm going to look into it more, perhaps on the weekend I'll try looking into my old university's database of engineering papers if they're still available to me, it seems I don't have anything on that particular subject available anymore.

 

[lomo]

Different design concept and I'll give Orange that however I too heard from those who owned and used them they were really not that great of cabs.

They are not the 1st to do this. It's old news, re-marketed.

 

[klejst]

They are not the 1st to do this. It's old news, re-marketed.

Sure, I meant by Orange though.

 

[Passinwind]

Am I wrong in interpreting that being the case because of WinISD's reliance on T/S parameters to calculate, among other things, sensitivity? I mean, isn't it reasonable that, beyond where cab design gradually stops playing a big part and (most) parameters cease to be of significance i.e. from the lower mids on up, the single driver cab should be 3dB louder than the iso, input wattage being equal, simply because it doesn't have to share the juice with the internal driver (which in turn isn't heard, midrange-wise, apart from some messing with the midrange response of its external twin)?

Now this part I can't figure out the reason why. (The fact I'm a dunce has probably something to do with it.)

Yeah, WinISD is useless above around 200Hz or so. FWIW, I took a look at my copy of Vance Dickison's book and he gave all of one paragraph to all the various iterations of bandpass cabs. To be honest, I've never looked into that subject in much depth, as the tradeoff sets just don't seem to favor my usual applications.

 

[BogeyBass]

Thermal rating doubles.

Takes double the power to reach same dB so yes it would be 3dB lower response.

Powerhandling to xmax is doubled but its 3dB lower so you end up at same place but need twice the power.

Only benifit is it half's the needed size of the box to get same bass response

Such as a single 12" needing 2 cubic feet would get same response in 1 cubic feet.

Isobaric mainly used for car stereo sub with limited trunk space. But wanting low frequency response but limited by volume. Say you wanted a 15" in 4 cubic feet but only had 3 available. A isobaric pair in 2 cubic feet would perform the same as a large 4 cubic foot box

 

[seamonkey]

Isobaric is not so bad. There are a lot worst designs where many drivers are just crammed into a small cabinet. If the drivers are good drivers, it's a waste of good drivers. If the drivers are bad, it's just a gimmick making people think more drivers are better. High power into a small cabinet, but terrible response.
Simple calculations and measurements show the truth, but marketing claims are big influences on people.