• Registered: 2023-10-16
  • Posts: 2

Topic: Equalization CCIR vs. NAB in PEQ

I own a Tape Recorder Telefunken M15A. The  Equalization is  CCIR.
If I play a NAB Tape it is not possible to change the Equalization.
Is it possible to do this with the PEQ in the ADI 2/4 pro SE ?
Has anyone done this and could tell me the settings of the PEQ ?

2 Reply by KaiS (edited by KaiS 2023-10-17 23:03:53)

  • KaiS
  • DAW Mastermind
  • Offline
  • From: Germany
  • Registered: 2020-02-05
  • Posts: 3,525

Re: Equalization CCIR vs. NAB in PEQ

Depends on the tape speed.


To play a 15 ips NAB tape on an IEC (CCIR) machine:
Bass: -11.0 dB, 30 Hz, Q: 0.5
Treble: +3.0 dB 2.3 kHz, Q: 0.5

To play a 7.5 ips NAB tape on an IEC (CCIR) machine:
Bass: -11.0 dB, 30 Hz, Q: 0.5
Treble: -2.5 dB, 1.63 kHz, Q: 0.5

The other way round, to play an IEC (CCIR) tape on a NAB machine, just change the gain value dB +/- signs.


You can find the 15 ips curve here, on page 6:
http://www.nomanlab.com/sale/lim_docs/nab_to_ccir.pdf

Here‘s a table with the standards, lines 3-6 are what you are looking for:
https://www.iasa-web.org/tc04/magnetic- … ualisation

Here are tables of the playback errors for both speeds:
https://www.aes.org/images/e-lib/thumbn … 2_full.png
https://www.aes.org/images/e-lib/thumbnails/1/5/1562_full.png

KaiS's Website

  • Registered: 2023-10-16
  • Posts: 2

Re: Equalization CCIR vs. NAB in PEQ

Thank`s KaiS, it helps a lot.

  • From: San Diego, CA
  • Registered: 2017-09-18
  • Posts: 79

Re: Equalization CCIR vs. NAB in PEQ

Unfortunately, your Telefunken machine is ALREADY ADDING CCIR EQ to its output, is it not?  You can't add NAB EQ after the fact, unless you are able to turn EQ OFF on the machine... and I'd be surprised if you could do that.

_____________________
Eric Seaberg • San Diego, CA • USA
A.E.S. • S.M.P.T.E. • S.P.A.R.S. • I.E.E.E.

5 Reply by KaiS (edited by KaiS 2023-10-22 01:28:46)

  • KaiS
  • DAW Mastermind
  • Offline
  • From: Germany
  • Registered: 2020-02-05
  • Posts: 3,525

Re: Equalization CCIR vs. NAB in PEQ

ericseaberg wrote:

Unfortunately, your Telefunken machine is ALREADY ADDING CCIR EQ to its output, is it not?  You can't add NAB EQ after the fact, unless you are able to turn EQ OFF on the machine... and I'd be surprised if you could do that.

Every tape machine has an EQ built in, typically either NAB or IEC/CCIR.
Usually integrated part of the heads amps, not bypass-able.


The corrections mentioned above are for converting IEC/CCIR playback EQ to NAB.
It’s not to fully replace the complete machine’s internal EQ, which is magnitudes stronger.

You can find a 15 ips machine’s internal curves here, on pages 4 and 5:
http://www.nomanlab.com/sale/lim_docs/nab_to_ccir.pdf


BTW: the NAB, IEC/CCIR standards define what magnetization has to be found on the tape, NOT how the machine manufacturer would achieve this.

The real EQ inside the machine might significantly deviate from the nominal curves, compensating various physical effects like head gap and bias related losses.
Professional tape machines can and have to be calibrated for linearity, offering a number of controls for this purpose, including typically two controls for playback HF correction e.g.

KaiS's Website