Zero Distortion: Oswald Mills - the OMA OMG tour

bonzo75

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A great read Ked. I had a feeling you might land on Apogee's as a final speaker, but held hopes you would find the right horn setup to convince you otherwise.

Hi Joshua, I did confirm on horns a few reports back. There are some good bespoke cheaper ones. Unfortunately I am not in Texas and room is the biggest issue, so I have to keep both in my pocket.
 

spiritofmusic

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Ked, the BD Oreo is €35k, really?
When I enquired a few yrs back was more like €22k.
It also needs biamping w SS for the bass towers, so the price rises if I want to use them w my SETs.
Makes more sense to run something like Haigners or yr fave horns out of Leipzig.
 

bonzo75

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The BD are high WAF and can be done to any size and shape.
 

KeithR

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I'd love to make that journey Kedar - thanks for sharing.

My friend has an OMA slate plinth for his Thorens and it looks wonderful.
 

bonzo75

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I'd love to make that journey Kedar - thanks for sharing.

My friend has an OMA slate plinth for his Thorens and it looks wonderful.

How does it sound. Is this the same guy with the Luxman TT?
 

KeithR

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How does it sound. Is this the same guy with the Luxman TT?

No - Kuzma Ref XL, Thorens 124 with a german wood plinth, Thorens 124 w/ OMA, and Technics 1200G right now. I have not compared the two Thorens as in different systems - I liked the 1200G more than the 124 wood but different cartridges so who knows.

He previously had Brinkmann Balance as well.
 

bonzo75

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What does he prefer?
 

bonzo75

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Which carts btw?
 

KeithR

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What does he prefer?

Well, the Kuzma XL is his reference rig - Thales, 4 Points, and Air Line arms. Atlas, Etna, Proteus carts.

I think I preferred his former Balance, but would like to hear the Kuzma again. The Brinkmann had more tone I believe.
 

Folsom

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Ked, if you talk to the really crazy Japanese guys who’s whole house becomes a basshorn, the consensus is that a TRUE Basshorn needs to be at least 24’ in length. Anything else may sound just fine, but isn’t a basshorn in the true literal sense. More just woofer bass w some added pseudo basshorn loading.
I know someone who stuck his head inside an AG Basshorn unit, the horn length is so minimal it has to rely on a ton of dsp, thus a true basshorn it is not.
I was always wary of Stereo’s idea to use Magico Ultimates. Just how is it “Ultimate” with a sealed woofer box?

This is because bass wave lengths are so long that they basically don't even see short horns. It's as if there is nothing there. All the horn really does is stop resonances problems, at best. Ideally you have a baffle be as big as 1 wavelength. So at 24ft you get very good, true horn, response down to 45hz.

1khz = 1.09ft
250hz = 4.38ft
125hz = 8.77ft
60hz = 18.27ft
30hz = 36.56ft
 

morricab

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One thing that generally strikes me about hte OMA speakers is their use of Conical rather than exponential or Tractrix or Spherical (eg. Avantgarde) horns. This is the oldest and most basic form of horn... I wonder what advantages it offers over the newer (1920s!) concepts? What are the disadvantages? For example, AG claims that their spherical horn design gives them less resonances and a more uniform wavelaunch vs. exponential horns, which from what i can tell have a better wave launch compared to the Conical horn from what I have been reading on the topic. Tractrix also is supposed to give a spherical wave launch (not sure how Tractrix differs from AGs horns...anyone know?). If that is the case, then is this OMA just getting all nostalgic for the oldest type of horn or is there something about it?
 

gian60

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Goto for their speaker always used this conical horn.
I remember Imai and Yamamura always told me this horn are no good and they used ALE horn or similar modified them with cork or graphite to stop the remaining vibration
 

lordcloud

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Thanks for this report. OMA is probably the number one company that I've been wanting to hear feedback on about the quality of their sound.
 

Solypsa

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One thing that generally strikes me about hte OMA speakers is their use of Conical rather than exponential or Tractrix or Spherical (eg. Avantgarde) horns. This is the oldest and most basic form of horn... I wonder what advantages it offers over the newer (1920s!) concepts? What are the disadvantages? For example, AG claims that their spherical horn design gives them less resonances and a more uniform wavelaunch vs. exponential horns, which from what i can tell have a better wave launch compared to the Conical horn from what I have been reading on the topic. Tractrix also is supposed to give a spherical wave launch (not sure how Tractrix differs from AGs horns...anyone know?). If that is the case, then is this OMA just getting all nostalgic for the oldest type of horn or is there something about it?

Bill Woods (who did speaker design for OMA) wrote a bit about this ten years ago or so...
 

morricab

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I also wonder why none of the designs use an actual bass horn if cost and space is no object?
 

Folsom

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I also wonder why none of the designs use an actual bass horn if cost and space is no object?

This is because bass wave lengths are so long that they basically don't even see short horns. It's as if there is nothing there. All the horn really does is stop resonances problems, at best. Ideally you have a baffle be as big as 1 wavelength. So at 24ft you get very good, true horn, response down to 45hz.

1khz = 1.09ft
250hz = 4.38ft
125hz = 8.77ft
60hz = 18.27ft
30hz = 36.56ft

^
 

awsmone

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Apr 6, 2014
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Although Correct on the wavelength in practice you only need a quarter the wavelength

Looking at the Monarchs width it would go down to 65 hertz, by quarter wave reinforcement (51 inch width )
With the diagonal which is hard to estimate probably it can make 50 hertz (67.5 inch)
I assume the 15 inch drivers can fill in down to 35 hertz, wouldn’t surprise me if they have different crossover frequencies, all other than organ which Kedar didn’t play frequencies pretty much lie above the 35 hertz mark,
 

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