Fostex in Azurahorn 204

[Defo]

Does someone have any experience with a Fostex driver like the 207 in the Azurahorn AH-204?

What concerns me the most is listening fatique and too much beaming. Ive had a pair of stereo-lab tractrix horns with compression drivers before, and the sweetspot was just too small for my taste.

And does anyone know the depth of the 65cm mouth version? Should the back of the driver have a chamber behind it or not?

Would be great if someone could help me out

[tinitus]

Originally Posted by Defo

Should the back of the driver have a chamber behind it or not?

On Martin Seddons Azura site you will find that the preferred design is his waveguide on front, and load the back into a big basshorn

Look into his gallery

Anyway, a narrow sweet spot is the nature of any good speaker
Anything else would be compromised

[CLS]

206 should be better for horn loading.

I've once had a short period of experience with Lowther PM4A and Oris 150. This combo sounded very good. A tad of warmth instead of razor sharp of 'regular' Lowther. A front horn would load the mid to low end of the driver's range very well. In a big throat horn like this, the loading is effetive in between lower cutoff and 2kHz or so. So a driver with inherent rising response actually helps a lot. I haven't heard Fostex drivers myself, but I'd guess the overall tonal balance should be similar and the differences would be in those detail and 'minor' things...

As to beaming, yes it beams inevitably as any widerange 8incher, but acceptable (I mean PM4A in Oris 150). You won't have a uniform sound everywhere in the room, but within proper seating area, it should be pretty much OK. If you do need a very large sweet zone, then please consider something else, like a 1" throat CD waveguide...

[Defo]

Originally Posted by tinitus

On Martin Seddons Azura site you will find that the preferred design is his waveguide on front, and load the back into a big basshorn

Look into his gallery

Anyway, a narrow sweet spot is the nature of any good speaker
Anything else would be compromised

The bass horn is a little too much for me, but I see he's running some drivers without a back chamber, and some with. Since I will need to place the horn as close to the back wall as possible, I guess its best to use a chamber?

Originally Posted by CLS

206 should be better for horn loading.

I've once had a short period of experience with Lowther PM4A and Oris 150. This combo sounded very good. A tad of warmth instead of razor sharp of 'regular' Lowther. A front horn would load the mid to low end of the driver's range very well. In a big throat horn like this, the loading is effetive in between lower cutoff and 2kHz or so. So a driver with inherent rising response actually helps a lot. I haven't heard Fostex drivers myself, but I'd guess the overall tonal balance should be similar and the differences would be in those detail and 'minor' things...

As to beaming, yes it beams inevitably as any widerange 8incher, but acceptable (I mean PM4A in Oris 150). You won't have a uniform sound everywhere in the room, but within proper seating area, it should be pretty much OK. If you do need a very large sweet zone, then please consider something else, like a 1" throat CD waveguide...

My bad. Meant the Fostex 206 ofc.

How did you experience the combo in terms of listening fatigue? Does a fullrange driver like the 206 beam more in the upper frequencies with a horn like the Azura 204 then without? As long as its less then my CD + stereo lab horn combo, then it might be acceptable.

[CLS]

In such big throat horn, above 2kHz or so, the driver can not see the horn. The horn almost does nothing to the driver. So you must consider the performance (character) of the driver itself. I'd guess a proper phase plug would help a lot here.

I myself haven't heard any Fostex. As to the Lowther PM4A, with its bulb shape phase plug, I felt the HF beaming was no so bad. And the Oris horn loaded it pretty well in the mid to midbass range and brought up a warm but detailed and dynamic sound, not fatiquing at all. But that's many years ago, the memory might fade away. What left in the remained memories are all good, though.

[Defo]

Originally Posted by CLS

In such big throat horn, above 2kHz or so, the driver can not see the horn. The horn almost does nothing to the driver. So you must consider the performance (character) of the driver itself. I'd guess a proper phase plug would help a lot here.

I myself haven't heard any Fostex. As to the Lowther PM4A, with its bulb shape phase plug, I felt the HF beaming was no so bad. And the Oris horn loaded it pretty well in the mid to midbass range and brought up a warm but detailed and dynamic sound, not fatiquing at all. But that's many years ago, the memory might fade away. What left in the remained memories are all good, though.

Thanks for the reply

I will most likely try out the drivers themselves first, and maybe some phase plugs, and see if it floats my boat. After all, the horns are almost ten times as expensive...

How about the rear chamber? I guess it should be sealed with a q about 0,7?

[CLS]

You're welcome

However, be careful in the evaluations of drivers, though. Horn loaded will change a lot to the overall characters (tonal balance) and performances (band width, sensitivity, dynamics, distortions... ). I said <you must consider the driver itself> meant the HF portion only, there's still a lot below that.

'Naked' drivers that sound awful don't mean they can not perform beautiful with horn. Mostly, quite the opposite. Most drivers suitable for horn loaded are not so good when not being properly loaded.

Originally Posted by Defo

...

How about the rear chamber? I guess it should be sealed with a q about 0,7?

Well, that's a lot of space for experiments. I have no paritcular answer. I'm using no back chamber right now -- just leave it open. Work for me.

[Defo]

How about the Tangband W8-1772? Any idea how it would work in a horn like the Azura 204?

[CLS]

If all the parameters are correct (honest), it should work. No guarrantee, of course.

Somewhat worried about the whizzer cone, though. Like all such drivers, above a certain SPL, the interferences between the main cone and whizzer always make things messy. In the previously mentioned Lowther PM4 in Oris 150, this can be very loud. However louder than that was possible in my usage, so I gave up that combo at that time. (I can accept that limitation now). I'm not sure how others perform in this area. If you like to listen in high SPL, please drop this idea. Only a proper 3 way can do.

At this point (and the way ahead), you'll be your own pioneer. Good luck!