Feastrex Fun

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My personal room...

My room is 144" x 160" and 8 feet high.
In this room I have the 5Dnf in a Maiko cab. The speakers are pulled way out into the room (63" from the rear wall and 39" from the side wall. The listening is very near field but the 5Dnf sounds really good in this small room.

The 9Dnf are going in my clients living room and that room is large. around 20' wide and 45' or so deep. The ceiling is from 10 feet to 15 feet. The room is ideal for OB and is very lively. Mostly wood floors and wood ceilings.

Phil
Santa Fe
 
Re: My personal room...

Phil Townsend said:
The room is ideal for OB...

Phil
Santa Fe
What would that be?
The size?
The "lively" part?
(just haven't yet heard an OB system I could listen to more than about five minutes, much less enjoy.
the closest was the Lowther set-up @ VSAC with Jeffery Jackson's 304TL amps carpeted floors & absorbers all over the walls.
That delayed sound bouncing around smears everything, kills detail & drives me crazy. there must be a way to do it that works though, so many people seem to like it...)
 
Re: Re: My personal room...

serenechaos said:

What would that be?
The size?
The "lively" part?
(just haven't yet heard an OB system I could listen to more than about five minutes, much less enjoy.
the closest was the Lowther set-up @ VSAC with Jeffery Jackson's 304TL amps carpeted floors & absorbers all over the walls.
That delayed sound bouncing around smears everything, kills detail & drives me crazy. there must be a way to do it that works though, so many people seem to like it...)


Can I assume a live instrument played in a moderately dampened room doesnt drive you crazy? What be the difference between dipole speakers and musical instruments that radiate sound front and back?

Cheers
B.
 
Live music in a moderatly damped (not dampened/wet :) ) room doesn't drive me crazy, IF it's not too loud, or some other problem.

The sound wave coming off of say, an acoustic guitar, does not sound anything like a recording of the same coming out of a dipole speaker to me.

On the live instrument all the sound is coming from one source, in phase and radiates in all directions, then interacts with the room.
Off a dipole, sound radiates in one direction in phase, in the other direction out of phase, canceles some out, comb filters some out, delays & combines and interacts with the room...
Not at all the same, and I'm guessing that's why it sounds so different.
It can make a nice effect to use when recording, if you want to add "space" or "ambience" to a recording, make it sound like it's being recorded in a bigger room. Play something, record it, play back through dipoles, & record the playback, just like electronic reverb, if that's what you're looking for.
 
I'm not sure the phase of the rear wave matters much, at least in the higher frequencies. Could be wrong here, but by my understanding using diffusion on the rear wall will result in short wavelength sounds arriving back at the listen in a largely random spread of phase. I have found that adding rear tweeters, for example, seems to raise output slightly as expected, but does not show up as measurable comb filtering at the listening position.

I'd agree though that one can have too much rear wave effect in most some rooms. I've got my dipoles 6' off the back wall and still prefer a little bit of absorption at the points of first reflection on that wall, whereas Linkwitz for example likes the front wall very much alive.

When you think about it though, dipoles add maybe only 25% more room into the equation, and phase wise its no different from the infinite number of reflections arriving from monoploes. Infact dipole are putting out a lot less to their edges so I think the differences are not huge, at least not beyond what some simple placement and room treatments cant make up for. If you chose to entirely deaden the wall behind a dipole youre effectively left with a monople minus box colorations.
 
Re: Re: Re: First Watt and Lowther at RMAF

Nelson Pass said:
It's still set up as a 4' X 6' OB. I replaced the PHL 18" drivers
with some Taiwanese OEM 18" that I got - light paper cones
with big magnets and voice coils. Much better due to the lighter
mass and the very low resonant frequency. As a result I'm
going to stick with these for a while.

I need to finish documenting these and the crossover performance,
and then the Lowther PM6A Ticonal/16 ohm silvers go in for another
comparison against the D9nf's.

After that, the PM6A without Ticonal, and PM6A's stock and the
Moths.

Probably then the D55's / A55's / C45's

The the SEAS Exotics

Then all the Audio Nirvanas.

Then the Fostex 166E, 166E with the bih magnets, and the 206E's

Then I'm going to start cutting the baffle width down in 6 inch increments
and experimenting with foam side diffusors.

It's going to be a long fall and winter....

:cool:


Admirable dedication :)))
 
Nelson Pass said:
Here's the first particle of data, a free air impedance curve of both
drivers. The top curve (@60 Hz) is one driver out of the box, the middle
one is the second driver, and the bottom is that same driver after
a short workout, showing lower Q from slightly broken-in suspension.

Nice consistency between the two.

Many thanks for all your good work Nelson. Mine have arrived safety from Oz (thanks Warwick!) Serials B0001 & B0002! Lahdi!

May I ask...

Has the resonance frequency of your D9nf's changed over the last six months as the suspension softens with use? Are we still the wrong side of 60Hz?

How do you regard the top end performance of the driver - in your opinion does it need a supertweeter (I ask because of the talk from others about using a ribbon above them)

I was rather hoping that this driver would cover either the top or the bottom end on it's own - I'm happy to concede to a two way design but I'd resent the complexity of a three way. I don't intend to try an OB design...

Much obliged
 
The one and only
Joined 2001
Paid Member
dpaws said:
Has the resonance frequency of your D9nf's changed over the last six months as the suspension softens with use? Are we still the wrong side of 60Hz?

How do you regard the top end performance of the driver - in your opinion does it need a supertweeter (I ask because of the talk from others about using a ribbon above them)

I was rather hoping that this driver would cover either the top or the bottom end on it's own - I'm happy to concede to a two way design but I'd resent the complexity of a three way. I don't intend to try an OB design...

Good question - this would be a good time to re-measure them.

I don't find the need for a tweeter on top, but it's certainly true that a fine
tweeter wouldn't hurt. My favorites are the smaller RAAL and the SEAS
Crescendo. I really like the Pioneer ribbons also, but they are no longer
available.

:cool:
 
Nelson Pass said:


Good question - this would be a good time to re-measure them.

:cool:

That would be great if you don't mind... let me know any costs incurred for a set of results and I'll Paypal - the info is invaluable for my enclosure project who's initial dimensions will be based on parameters.

WRT tweeters, I was looking at the Focal TBe (fantastic small form factor), the 4Pi or the Raidho planar but... how would I correctly position either as I would need almost a concentric mounting at 16kHz...

Would it be better to simply fire them upwards ("ambience style") rather than trying to create a coherent point source?
 
The one and only
Joined 2001
Paid Member
dpaws said:
Has the resonance frequency of your D9nf's changed over the last six months as the suspension softens with use? Are we still the wrong side of 60Hz?

I re-ran the curves and they did not change significantly. Within the accuracy
of the test (nominal room temperature, etc) the impedance peak is at the
same 64 Hz with a peak value within a few percent.
 

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

....................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. :cool:


Dear Nelson,

May I ask if there is any progress/ updates going with your toys - full range drivers ?
:)
 
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