Hi, Andrew,

Yes there will be changes, but they are not huge and the slope is gentle 
(less so with AME). Look at and look at the Choosing 
and Using a test tape document -- there are cross references between 
standards for applying a calibration tape of one standard to another.



On 2011-01-29 3:23 AM, Andrew Hamilton wrote:
> On Jan 28, 2011, at 10:12 PM, Richard L. Hess wrote:
>> ...One of my clients likes it that we can pitch the tapes for him in 
>> the analog domain.
> Dear Mr. Hess, et al.,
>      I was wondering how much speed tolerance there is to a given 
> pre-/de-emphasis EQ, even if a vari-speed oscillator is available.    
> Say there is a 1 kHz tone at 990 Hz, and you know they had intended 
> the EQ to be NAB...   Had the horse already left the barn (in terms of 
> the emphasis's efficacy) when they were signaling a 1k sine, but the 
> machine was turning a bit faster than 15 ips (say, 15.2 ips)  and 
> turned the 1000 cycles per second into 990 cps when played back at the 
> intended record speed?   Or, by speeding up the playback machine to 
> 15.2 ips - enough to make the intended 1k tone actually play 1000 cps 
> - does the vari-sped playback (at the original record speed) magically 
> de-emphasize the haunted pre-emphasis?  What is the point at which an 
> alteration should be made to the pre- and/or de-emphasis EQ?  
> (Obviously, if the recorder is turning at 20 ips or higher, a 
> different emphasis eq has to be set, whence the custom curves - let 
> alone AES and AME.)
> Thank you,
>      Andrew

Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada           (905) 713 6733     1-877-TAPE-FIX
Quality tape transfers -- even from hard-to-play tapes.