Rmaf 07

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Vix

Vix

Member
Joined 2003
Hi,

I was surprised because I expected something around 100-150Hz for the highpass. (at least)

However, Nelson took a different approach. By crossing so low he actually made the Lowther work almost full-range. 60Hz might be the point where it short-cuts, so anyway it wouldn't be making much below that. High-pass seems to be there just to relieve the Lowther of doing a lot of excursion with no audible benefit. So, there are two bass drivers to fill the bottom end. I'd say that this approach is more hi-fi, and must sound better than those that are crossed higher. The drawback: Reduced max SPL. But, once you start enjoying OB sound, you won't feel an urge to turn the volume knob...

I guess that Nelson thought this way while listening and drinking a glass of wine...

Please correct me if I am wrong....

Regards,

Vix
 
C

chrisb

Member
Joined 2002
Lynn's perspective on this matter:


didn't like the First Watt crossover at 75 Hz at all. As MJK's paper makes clear, an 8" driver in a fairly narrow baffle needs a fairly high crossover, maybe around 200~250 Hz, and it is asking very little of open-baffle woofers to be flat up to 250 Hz, epecially a pair of little bitty 10" audiophile woofers with fancy phase plugs.

What makes the higher crossover a matter of necessity rather than choice is the extremely small Xmax of the Lowther, no greater than the Xmax of a good 1" dome tweeter. By crossing the Lowther at 75 Hz a lot of distortion is assured at almost any playing level, and that's what I heard - the onset of harshness was pretty rapid with increased level, and was to some extent noticeable with all program material.

Moving two octaves higher would have cleaned up things a lot - and if woofer coloration is noticeable at 300 Hz, well, that says something about the choice of woofers, doesn't it? Any decent woofer short of an 18" subwoofer should handle 300 Hz with grace and ease.
Click to expand...



extracted from post, I trust is this not taken out of context:

http://www.diyaudio.com/forums/showthread.php?postid=1326301#post1326301
 
BudP

BudP

Member
Joined 2007
Hi all,

Jon Ver Halen tells me that the 15 ohm PM6A actually has 3mm of xmax. I suspect Nelson was taking advantage of this, as the 8 ohm model has only 1mm.

For that reason I now have a pair of 15 ohm PM6A's and am going to build the ugliest speaker in the world. Omni Lowther, OB Eminenece Beta 8 , Tang Band W8 740 C for the transmission line. Beta 8 to run without low pass and the crossover point to Lowther TBD. Tang band driven with a plate amp.

All EnABL'd, of course.

Bud
 
C

chrisb

Member
Joined 2002
BudP said:
Hi all,

Jon Ver Halen tells me that the 15 ohm PM6A actually has 3mm of xmax. I suspect Nelson was taking advantage of this, as the 8 ohm model has only 1mm.

For that reason I now have a pair of 15 ohm PM6A's and am going to build the ugliest *speaker in the world. Omni Lowther, OB Eminenece Beta 8 , Tang Band W8 740 C for the transmission line. Beta 8 to run without low pass and the crossover point to Lowther TBD. Tang band driven with a plate amp.

All EnABL'd, of course.

Bud
Click to expand...


I dunno Bud, I think WA has that* sewn up
 
planet10

planet10

frugal-phile™
Joined 2001
planet10-hifi.com
Paid Member

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BudP

BudP

Member
Joined 2007
chrismercurio

My wife is CEO of our transformer company and is willing to put up with R&D insults in the living room/audio test center. Her comment lead me to believe that they were actually uglier than I thought. I just claim it is a Bauhaus based design so form follows function, offer to show the simulations and she just walks away shaking her head.

Cal
I am still awaiting the Tang Band drivers so I haven't any experience, so I am glad to hear you are happy with them.

Bud
 
Pano

Pano

Administrator
Joined 2004
Paid Member
I was sitting right beside Lynn Olson for the demo. I've posted my thoughts on the EnABL Thread. (post #768)

Lynn has much more sophisticated hearing than I, so take my report with a grain of salt, but it's what I heard.

Thanks Jon Ver Halen for running the demo. Great sounding rig, either way.
 
chrismercurio

chrismercurio

Member
Joined 2006
I know, I know,

the divorce comment was a little harsh.

Honestly I could get away with a lot more strewn about the living room before we were married. Now with a little one, all kinds of stuff is strewn everywhere, it's just not mine!

My test baffle with the ti-100 and PR170mo mounted to it got some interesting comments from the wife when she came home from yoga...if I had a digital camera I would post pix. Picture a 17"w x 48" h .75" piece of mdf with that cute little visaton and the audax on opposite sides and the whole thing propped up with Bessey clamps. Not exactly d-i-v-o-r-c-e but more like, wtf is in MY living room?

C
 
Nelson Pass

Nelson Pass

The one and only
Joined 2001
Paid Member
Studley said:
The usual counter argument to using active Xovers is that the advantages are outweighed by the disadvantages of putting more circuitry in the signal path.

Would you care to comment on your new "special" Xover in this context?
Click to expand...

That is the counter-argument. In the end, you try things and see
what works out best. Trying to get this result passively is
cumbersome and requires a lot more power amplifier, and so
was an easy decision.

:cool:
 
Nelson Pass

Nelson Pass

The one and only
Joined 2001
Paid Member
Re: Favorite Stories

Jon Ver Halen said:
None of these quotes are totally accurate, but are meant to give the gist of the conversation:

Visitor "You cannot hook Lowthers up to solid state amps"
Nelson "And when was that law passed?"

(etc.)
Click to expand...

What I enjoyed about this system is that we broke as many rules
as possible:

"You can't drive Lowthers with solid state"

"You can't get low end out of open baffles"

"You can't get low end out of such tiny open baffles"

"You can't get good sound out of MDF baffles"

"You can't get good sound out of baffles that vibrate like crazy"

"You can't use a speaker in the middle of the baffle"

"You can't cross a Lowther at that frequency"

"You can't cross a Lowther at that slope, either"

"You can't drive a Lowther that hard."

(repeat previous three, substituting "SEAS" for "Lowther")

"You're joking using those Kimber pythons for speaker cable"

"You can't be serious using a Sony player"

and finally:

"That can't be a steam locomotive coming through the wall!"

:cool:
 
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