In article , Don Pearce
wrote:


OK, got that. Why didn't they think to use a log horizontal scale rather
than that muddle?

I think it is just the standard B&K penchart from the period. They used the
usual B&K sweep generator and associated equipment.

It is the bit over 5kHz that is the problem though. That centre panel is
a fair bit bigger than your average tweeter and will get rather beamy.

Yes. Difficult to avoid that with most ESL designs. Although you can try to
curve the diaphragm like some do, that can add its own problems.

That said, for reasons I give elsewhere, I am not personally worried by
this as I suspect it actually can be used to tweak the imaging to work
better! And in practice although people think of 'treble' reaching to 20k
or more, most of what affects our perception tends to be at much lower
frequencies.

Slainte.

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On Sat, 06 Aug 2011 09:52:46 +0100, Jim Lesurf
wrote:

In article , Don Pearce
wrote:


OK, got that. Why didn't they think to use a log horizontal scale rather
than that muddle?

I think it is just the standard B&K penchart from the period. They used the
usual B&K sweep generator and associated equipment.


I used a B&K audio sweep setup myself back in the seventies. It had a
Bowden cable drive between the oscillator and the chart recorder -
which used a stylus on waxed paper. That definitely had a log
frequency scale, though.

It is the bit over 5kHz that is the problem though. That centre panel is
a fair bit bigger than your average tweeter and will get rather beamy.

Yes. Difficult to avoid that with most ESL designs. Although you can try to
curve the diaphragm like some do, that can add its own problems.

That said, for reasons I give elsewhere, I am not personally worried by
this as I suspect it actually can be used to tweak the imaging to work
better! And in practice although people think of 'treble' reaching to 20k
or more, most of what affects our perception tends to be at much lower
frequencies.

Slainte.

In the parlance of the music biz, "air" is about 12kHz, "sparkle" at
6-8kHz. I think air is about the highest you need, mostly.

I can't hear much above the air band anyway (14.5kHz is my limit now)
so I'm not bothered by it either way.

d