Feastrex Fun

[Vix]

Hi Nelson,

Is there any chance to post a pic of a backside of your Open Baffle speakers?

Thanks,

Vix

[Nelson Pass]

Originally posted by Vix
Is there any chance to post a pic of a backside of your Open Baffle speakers?

There's nothing to see. All the baffles have an unobstructed path
from the full range driver to the edges - this being quite important.

The latest all use support spines centered horizontally, running from
top to bottom, and some have horizontal spines radiating side to
side from the driver.

Some have small wings on the bottom sides to add to the woofer
path, some don't.

The range of sizes is is 16" X 40" up to 36" by 60"

[Vix]

Originally posted by Nelson Pass



Some have small wings on the bottom sides to add to the woofer
path, some don't.

Here is the point. I am experimenting with additional side wings, and trying to estimate the most appropriate shape/size. Originally, my OB's, being a copy of Visatons NoBox design, had large side wings. As those wings added weight to the bass, they also compromised the "openness" of the sound, and I did not like it. So, I removed the side wings completely, and it sounded much better in the midrange, while the bass has gotten weaker. Now, I am trying to figure out if placing some small wings, just up to the half height of the baffle (just enough to "cover" the woofer) will be the best compromise, bringing back some bass without loosing the midrange magic.

I wanted to see the back of your OB's because I couldn't see whether it was one piece of the supporting spine, or there are two small wings on the bottom sides to add to the woofer path (looks more like this).

Thanks a lot,

Vix

[Nelson Pass]

The support spine's acoustic effect is largely stiffening the baffle board.
Half-wings for the bottom are an option, and they will give you a little
more bottom, but you should also be prepared to toss a little EQ at it.
Sometimes I use it, sometimes I don't, depending on baffle size and
the bass driver.

If you are adding wings to the top half and don't want to compromise
the "openness" then make the wings co-planer with the surface of the
baffle - in other words, extend it straight out, not at an angle, and
try not to block the sound traveling on the surface of the baffle.

Of course, there is such a thing as a too-large baffle. It looks to be
somewhere between 24" X 48" and 36"X60"

[Vix]

Originally posted by Nelson Pass
Of course, there is such a thing as a too-large baffle. It looks to be
somewhere between 24" X 48" and 36"X60"

My Open Baffles have reached the top of the WAF limit. So, I may equalize, do whatever, just not make 'em any bigger...

Thanks,

Vix

[Steve M]

Hello Nelson,

I'm still a little curious as to your views on Lowther compared to Feastrex? I appreciate that someone of your standing needs to be discrete, but just a 'little' clue would be nice for some of us where the price difference is like going for a holiday to Hawaii/Bali or taking a trip to the moon ...

I wholeheartedly agree with your earlier comments about people needing to take the jump from things like Fostex to Lowther/Feastrex. For me the difference is like chalk and cheese and it all comes down to TONE and SPEED. The Lowthers are just a whole lot tonally nicer and its quite obvious that they are a lot faster and better at the transient edges of the music. Best way to describe it is that Fostex sounds like the music is trapped in the box or within the mechanics of the driver, whereas the Lowther lets the music out into the room, free and unfettered.

That said, no cone driver on the planet keeps up with the ER Audio ESL-3 ( www.eraudio.com.au ), a 3.4 micron thin membraned electrostat that gives you an electron microscope's view on the recording - and makes even the Lowther sound mechanically clumsy!

Regards,

Steve M.

http://forum.audiogon.com/cgi-bin/fr...146370182&view

[Nelson Pass]

My best full range drivers are the Feastrex D9nf and the Lowther
PM6A (Ticonal Alnico magnet and an overhung silver 16 ohm voice
coil).

You can surmise that I lean toward the larger drivers more than
the smaller versions offered by both companies, although the
smaller Lowthers definitely have better upper mid and top end
than the 8 inch Lowthers. (I haven't spent real time with the
D5nf, so I won't presume)

Both are used in flat open baffles, currently 24" X 48" with 15 inch
woofers and an active crossover of my own devising. The
crossover point is largely dictated by the baffle size, and currently
this ranges roughly between 100 and 200 Hz, with 2 pole
networks and drivers in-phase.

This is still a work in progress on all fronts - baffle design, woofer
selection, crossover design....

A few factual items:

The Lowther has the smoothest frequency response overall,
although this seems to be unique to this particular model.

The D9nf curve has a mild broad peak in the upper midrange, but
it is easily compensated out.

The Feastrex has more response up at 20 Khz to 30 KHz.

The Feastrex has a couple more DB sensitivity, although my
overhung Lowther voice coil is partly the reason for that.

The "fit and finish" of the Feastrex is the envy of other
manufacturers, no question.

The Feastrex has great bragging rights (if you own a pair).

You can repair a Lowther yourself, or get Jon Ver Halen to do it.

These Lowthers cost about $1500/pr from Lowther America

The D9nf's are about $6000/pr from Lotus Distributing.

Opinions?

Both of these drivers beat all other contenders so far, so for me
it's just down to the two of them. I own both, and as with my
children, I have no need to prefer one over the other.

Overall they have a lot of similarities, but it's clear that the
Feastrex has a little more detail, and the Lowther is a little
smoother and relaxed.

At the moment my favorite "little" amp on the Lowther is the F5,
and on the Feastrex it's the F3.

I can easily recommend either. I do need to spend significantly
more time with both, and time is always in short supply.

Ask me again in a year.

[Scottmoose]

Originally posted by Steve M
I wholeheartedly agree with your earlier comments about people needing to take the jump from things like Fostex to Lowther/Feastrex. For me the difference is like chalk and cheese and it all comes down to TONE and SPEED. The Lowthers are just a whole lot tonally nicer and its quite obvious that they are a lot faster and better at the transient edges of the music. Best way to describe it is that Fostex sounds like the music is trapped in the box or within the mechanics of the driver, whereas the Lowther lets the music out into the room, free and unfettered.

Wouldn't that be dependant upon whether a person is able to afford such luxuries?

Sure, as a rule, you get what you pay for. We all know that. However, whether they are a sufficient improvement for a music lover on, say, a £20,000 per-year wage (average UK earning) to spend a highly significant portion of his / her yearly income without batting an eyelid is more of an issue. As I see it, such things tend to be skewed dependant upon position; a fact which can sometimes be overlooked. Those with few monetary issues may regard something as a dramatic leap forward, whereas those at the opposite end of the financial spectrum might well regard the same thing as only moderate to slight. As someone on a low income, while I acknowlege that the pricier units offer superior performance (in some areas, but not automatically all) I'd need my head looking at if I decided to buy a pair. Quite simply, the improvement is nothing like sufficient for me to compromise morgage, insurance, transport, health, energy & food requirements for self & family in order to attain it.

Just my tuppence worth anyway. And like everyone I can always dream... (although I generally prefer to reflect on the idea of Liv Tyler between satin sheets than drive-units )

[cdwitmer]

Originally posted by Nelson Pass
Overall they have a lot of similarities, but it's clear that the Feastrex has a little more detail, and the Lowther is a little smoother and relaxed.

Very interesting. I wonder how the two drivers might compare when used as fullrange single drivers (obviously not possible on open baffle, of course) . . .

-- Chris

[Scottmoose]

A good question & I for one would be fascinated to find out. Something tells me they aren't going to be leaving Nelson's baffles for a while though...