7 1/2 / 15 / 30 ips ?

[Audio Al]

Silly question time :)

Why do people say that recording at 30 IPS is better than 7 1/2 or 15 IPS ?

Opinions please :)

[Cas]

Very basic but it does explain the reason for faster tape speeds sounding better.
https://www.schoolphysics.co.uk/age14-16/Electricity%20and%20magnetism/Electromagnetic%20induction/text/Tape_recording/index.html

[Audio Al]

OK so it's this

The faster the tape moves the better the recording because the information (lets say the music) is spread out over a longer piece of tape. Slow tape speed compresses the information into a small length and a poorer recording results. The recording head should be as close to the tape as possible so that the changing magnetic field can affect the iron oxide grains more easily.

Thanks :)

[Cas]

OK so it's this

The faster the tape moves the better the recording because the information (lets say the music) is spread out over a longer piece of tape. Slow tape speed compresses the information into a small length and a poorer recording results.

Thanks :)

That's it :)

[Barry]

The shortest wavelength that can be recorded onto the tape is determined by the width of the head gap. Thus the highest recordable frequency is thus given by (recording speed)/(gap width), so the higher the recording speed the higher the frequency that can be recorded.

It's not quite as simple as that, but you get the idea.

[Ali Tait]

Same reason 45rpm will sound better than 33 given a level playing field.

[Audio Al]

Same reason 45rpm will sound better than 33 given a level playing field.

So where does half speed masters come in then :scratch:

[Stratmangler]

So where does half speed masters come in then :scratch:

The cutting stylus doesn't get as hot cutting the high frequencies because the high frequencies are halved.
The higher the frequency, the hotter the cutter stylus gets, and if there's too much high frequency information at too high an amplitude the cutting stylus will literally burn out.

[Pigmy Pony]

I remember my VCR having a "long play" facility, where it could record and play back at half speed, so doubling the available length of programmes you could record. Picture quality wasn't as good though.

[topoxforddoc]

Allen,

The multitrack 1970s/1980s session masters were usually on 2 inch tape at 30 IPS with 16 or 24 tracks. The original stereo mix down master was usually a 30 IPS 1/2 inch tape. Production or distribution tapes were copied form the 1/2 inch 2 track stereo master and sent out to record pressing plants. Most production masters were sent out on 1/4 inch tape as 15 IPS 2 track.

Charlie

[camtwister]

Apart from causing less mechanical stress to the cutting head and its benefits to inner groove shaping and dynamic range as Chris notes,
half-speed mastering can also improve equalisation and pitch control.
This is because computer controlled mastering apparatus cut using a variable pitch principle which uses a look-ahead function and this is more efficient at lower frequencies.
It also removes the problem of instability in feedback loops at frequencies prevalent in full-speed mastering.