audio standards at low V+

[Walter Harley]

You people doing audio work with cutting-edge chips: what nominal signal
voltages are you using?

It seems like most new chips I see these days are aimed at the supply rails
used for high-speed digital circuitry, 3.3V being the most common, 1.8V not
unusual. This includes chips aimed at audio, including pro audio (e.g.,
high-quality ADCs).

In professional audio gear interconnects, 0VU = +4dBu (1.23Vrms) is the
standard. Back in the day, using chips that took +/-15V rails and got
within two diode drops of the rails, you got about 18dB of headroom. For
consumer gear, 0VU = -10dBV (316mVrms) is also a common standard. To get
18dB of headroom over that, you'd need supply rails of +/-3.5V, assuming
rail-to-rail ins and outs.

So what do you folks do with these 3.3V chips (that's not +/-3.3V, it's a
single supply)? That gives you 11dB headroom over a -10dBV 0VU signal; is
that what everyone settles for now? Or is there some other emerging
standard, and if so, what?

Thanks!

 

[Ian Bell]

Better with no huge JPEGs on the first page (or you risk loosing the
interest of dial-up customers).

Dead right. I think I might compress them a fair bit more anyway.

Are your walls really as non-parallel as the first photograph suggests
or is it an artifact of the wide-angle camera lens?

That was no wide angle lens. The walls really are that non-parallel. The
building is about 200 years old. One long wall is about a foot longer than
the other.

Ian

 

[Adrian Tuddenham]

Dead right. I think I might compress them a fair bit more anyway.


That was no wide angle lens. The walls really are that non-parallel. The
building is about 200 years old. One long wall is about a foot longer than
the other.

Brilliant anticipation on the part of the original builder.

 

[Ian Bell]

Brilliant anticipation on the part of the original builder.

It does mean that the asymmetry in combination with the random brick
orientation and flint stones provides quite a good basic acoustic.

Ian

 

[Ted Edwards]

Ban wrote:
...

You didn't have to read even that much of his crap. Anybody who talks
of rms power is a non-starter.

Ted

 

[Ian Bell]

You didn't have to read even that much of his crap. Anybody who talks
of rms power is a non-starter.

Ted

Did he? I missed that one.

Ian