Same here. Never had a high freq drop on any of my tapes.
Shai

On 1/14/2011 6:43 PM, Goran Finnberg wrote:
> Tom Fine:
>
>> as the cassette naturally
>> loses its level over time.
> Naturally?
>
> Can you give me some hard facts here, Tom.
>
> I have asked this question approx 10 year ago directly via email to Jay
> McKnight an apart from oxide shedding, external magnetic fields, magnetized
> heads there is no known source why the level or treble should decrease with
> time according to him.
>
> Also....
>
> I am asking because during 15 years I was professionally involved in a
> cassette duplicating plant using Gauss, Lyrec, Ampex, King, Heino-Ilsemann,
> Apex, Studer equipment etc.
>
> None of the high speed duplicated cassettes I still have, several 100, and
> none of my approx 60 BASF, Nakamichi and RCA test cassette tapes show any
> change in level or frequency response either objectively or subjectively IF
> the azimuth is very carefully adjusted on my Dragon, 582 or 682 Nakamichi
> decks.
>
> The ONLY thing I´ve seen that changes level is if the replay head is not
> correctly adjusted in height and frequency response above a few kHz is
> directly linked to azimuth and gap loss together with using the relevant
> first orfder gap eq to correct for gap loss above approx 15 kHz.
>
> BTW, professionally duplicating equipment set up correctly, IS capable of
> such good duplicating quality that it will fool 99.9% of all listeners in
> direct A/B test compared to the original sound source.  with ease.
>
> Needless to say the loop bin master must be changed regularly as it ages for
> this to hold true.
>
> So my own experience using magnetic media for some 50 years has not turned
> up any such problem practically.
>
> Even my BASF 15"/38.1 cm/s 35µS CCIR/IEC testtape dated 1968 is within 0.1
> dB of a few years old MRL G320 nWb/m testtape in its reference fluxivity and
> the frequency response is still within a few 1/10 of a dB to 18 kHz when
> replayed on a flux loop calibrated Studer A820 despite being used +400 times
> according to my log.
>
> BASF test tapes were always hot at the high end to the tune of a dB or so to
> offset user losses caused by magnetized heads, guides etc and this can still
> be seen.
>
> BASF test tapes had four repeats of the 1 kHz to 18 kHz bands and playing
> repeat 3 which has only been played two times compared to the normal
> frequency run shows a difference of only 0.3 dB at 18 kHz.
>
> This test tape was recorded on BASF LGR30P red oxide tape.
>
>