[versus rider]

would this driver be ok in open baffle, bearing in mind that only bass comes out the back of the driver, so lowther claim.

[Russell Dawkins]

I read something to this effect just the other day, but I would be very surprised if the source of this "information" was Lowther. Could you cite the source, please?

Simple science will tell us that the bass will "come out of"  the back and front of a cone driver equally, with rear output in inverted polarity to front. At increasingly higher frequencies, you can expect less from the rear as it is blocked by the motor assembly, but as you go lower in frequency (and longer in wavelength), this blockage will be less and less a factor, until at the frequencies typically affected by the rear horn loading or reflex box resonant boost, the output front and rear would be essentially the same.

It is the rear portion of the output, though, that is used for augmenting by the horn or the box - maybe that's the source of the confusion.

[versus rider]

Each model in the 'EX' range incorporates an acoustic chamber precisely tuned for optimum performance. Cone assemblies are pressure balanced between the acoustic chamber at the rear and a phasing equalizer fitted to the front. No unwanted oscillations of the speech coil occur. Only bass frequencies will pass through the acoustic chamber, so avoiding bass/mid-range confusion, often a cause of coloration.

this is directly from the lowther website. If you have seen an EX driver it is not possible to see the cone from the rear. There is a metal cover with holes and inside is foam. I am going to try these EX3's in my open baffles, I'm not concerned about what comes out the back really, my only concern is that I won't damage the drivers by running them ob.   

obviously bass comes from the front of the driver, if that is what you were getting at. Providing you are prepared to wait for about a year.

[versus rider]

I was informed by Diane at Lowther that the EX3 wasn't suitable for open baffle but the DX range is suitable. Other than the acoustic chamber the specs are almost identical.

[Russell Dawkins]

Each model in the 'EX' range incorporates an acoustic chamber precisely tuned for optimum performance. Cone assemblies are pressure balanced between the acoustic chamber at the rear and a phasing equalizer fitted to the front. No unwanted oscillations of the speech coil occur. Only bass frequencies will pass through the acoustic chamber, so avoiding bass/mid-range confusion, often a cause of coloration.

this is directly from the lowther website. If you have seen an EX driver it is not possible to see the cone from the rear. There is a metal cover with holes and inside is foam. I am going to try these EX3's in my open baffles, I'm not concerned about what comes out the back really, my only concern is that I won't damage the drivers by running them ob.   

obviously bass comes from the front of the driver, if that is what you were getting at. Providing you are prepared to wait for about a year.

Well, sorry. I guess I mis-read your initial post as "bass only comes out of the back".

In any event, I am guessing the "acoustic chamber" at the rear is mainly an acoustic filter to block mids and pass lows, and because of its resistance requires the use of the "phase equalizer" to reduce the tendency of the cone to pump itself forward on sustained bass notes.
All this should mean is that there is reduced mids out the back, and I don't see why it is deemed unsuitable for OB use by Diane. In fact, due to the extra cone motion damping preventing "unwanted oscillations of the speech coil", I would have guessed it would be more suitable - especially with a bass driver supplementing it to compensate for the slightly earlier bass roll-off of the EX3 caused by the acoustic chamber.

As to having to wait for a year for the bass coming from the front; the acoustic chamber will not affect the arrival time of bass from the front at all - it will be just be reduced in level.

Of course this chamber on the back of the EX series is meant to reduce the midrange noise from inside the box from contaminating the sound by re-radiating through the cone, but this is one of the big benefits of the OB in the first place, and so this is completely redundant in this application.

[versus rider]

you would appear to have quoted me with the inverted comma's. I actually said " ONLY bass comes out the back " and not bass only. Very different. Let me just say that I do in fact have a pair of these drivers that I bought for lowther fidelio cabinets and  because they are taking so long to run in I have decided to either sell them ( sale pending subject to buyer selling his 16 Ohm versions ) or try them in my ob's. Oh and btw I am fully aware that the acoustic chamber has no bearing on the bass from the front just Lowthers taking an age to run in.

[versus rider]

I decided to give the lowther EX3 a try in my open baffles. I bought these drivers about 5 months ago for my fidelio cabinets and they are still not run in, even though I have left them running most days while out at work. Someone told me his took a year to run in. Bass when fitted in the fidelio is improving but not that great when compared to other speakers I have. I fitted and wired the lowthers and connected to my 2A3 mono's. Well they were dreadful, no midbass whatsoever and shouty, thin sounding not at all what you would expect from such expensive drivers. I will stick with my cheap unknown make drivers that worked straight out the box, nice flat response and good down to 100hz, maybe lower but haven't checked them yet.