1. BAS Speaker V40n4 has been
published. This completes the fourth volume in our CDR series
of BAS archive documents (dating back to our first issue). It
features coverage of the 145th AES convention by David Weinberg
and CEDIA Expo 2018 by Kenneth Wacks and Favorite Recordings
Meeting 2016 by David Hadaway.
2. RIAA In the Stereophile
review of the Levinson No. 5805 Integrated Amplifier, John Atkinson
notes that the RIAA phono response is up .6 dB at 20 Hz. The
Audia Flight FLS1 ($6995) is down 3 dB at 20 Hz.
At first I thought the Audia was yet another
example of high priced poor design, but then I realized it was
implementing the IEC recommended low frequency rolloff, designed
to reduced rumble problems. However there is no corresponding
boost in recording LPs (and never likely to be) so it is simply
an audible error (-1 dB at 40 Hz). Space is at a premium on
records and low frequencies take up a disproportionate amount
of space. As Bert Whyte famously said If I had a dime
for every record cut with a high pass filter I would be sipping
Don Perignon on my yacht. If you need to reduce rumble
the proper solution is an 18 dB Butterworth (maximally flat)
low filter which effectively reduces the lows without affecting
the audio. The Davis-Brinton Preamp used an even steeper initial
cutoff, a Chebychev filter, at the expense of ripple in the
There is no excuse for not doing the RIAA
right calculating the values and implementing them.
For comparison the DB Systems DB-8 Phono
Preamplifier (1995) is +/-.04 dB, 20 Hz to 20 kHz ($175).
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