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Altec 511B Measurements
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Author:  J-ROB [ December 26th, 2017, 4:22 pm ]
Post subject:  Re: Altec 511B Measurements

The reason some horns are rectangular is to limit the vertical dispersion in order to avoid interference from floor and wall reflections at the lower end of the response. This is a feature not a bug.

I have used round tractrix horns, particularly the famous Edgar "salad bowl" horn. Very precise, however I could only get one ear into the microscopic sweet spot at a time.

Ultimately I found them unusable for this reason. There was no stability of the presentation as I moved around...and I am talking horizontal movements of one foot at 15-20' distance.

Now that was a fairly long tractrix horn but it was the beamiest thing I have ever used. I have heard and used a few other shorter round tractrix and rectangular tractrix, cone and CD driven, with much more satisfying results,

Given that you are planning a five way, do you think that a beamy character will not intrude upon the coherence you seek?

Anyway I don't understand why you are being so hush-hush about the source of the tractrix horns.

Most horns out there were not made by members of this forum.

It seems you are making sweeping claims based on a sample size of ONE, which is why I am interested.

Author:  Cogito [ December 26th, 2017, 5:02 pm ]
Post subject:  Re: Altec 511B Measurements

Quote:
The reason some horns are rectangular is to limit the vertical dispersion in order to avoid interference from floor and wall reflections at the lower end of the response. This is a feature not a bug.


True, but that "feature" is based on altering the sonic waves. In an audiophile purist world, that is not a desirable thing. I would rather have a spherical dispersion with additional diffusers on the ceiling,


Quote:
Now that was a fairly long tractrix horn but it was the beamiest thing I have ever used. I have heard and used a few other shorter round tractrix and rectangular tractrix, cone and CD driven, with much more satisfying results,


Exactly.

a 6kHz signal passing thru a 500Hz horn will do two things:
1. Part of the signal will pass thru (beaming)
2. Part will resonate in the horn as the length of the horn is too long for wavelength of 6kHz.

That is why I am planning to use two horns of different frequencies.

Author:  Roscoe Primrose [ December 27th, 2017, 12:57 am ]
Post subject:  Re: Altec 511B Measurements

J-ROB wrote:
Who makes the 500hz tractrix you are using, to restate my question?


They're a JM Le Cleac'h based horn that Gary had made...

Roscoe

Author:  Cogito [ December 27th, 2017, 7:56 pm ]
Post subject:  Re: Altec 511B Measurements

Roscoe Primrose wrote:
J-ROB wrote:
Who makes the 500hz tractrix you are using, to restate my question?


They're a JM Le Cleac'h based horn that Gary had made...

Roscoe


The horns I have do not have the LeCleac'h mouth rollback.

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