Learn The Key Differences Between Analog Tape Speeds

by | May 5, 2015 | Home Recording, Music Production

What Speed Do I Need?
Examining The Differences Between Recording Tape Speeds

So I’m told there has been a renewed interest in vinyl records and analog recording lately. It seems that some auspicious music publications are even dedicating entire issues to the subject!  According to Forbes (or was it the Times, no, maybe the Wall Street Journal, eh, I don’t remember and it doesn’t matter), vinyl sales doubled in the past year.   As many vinyl pressing plants converted production to CDs, or closed entirely, the ones that have remained can’t keep up with today’s demand and orders are routinely 2-3 months backlogged.

Now hold on, before you start buying stock in vinyl record manufacturing, keep in mind that some experts are suggesting this is simply a fad, a final nostalgic nod to the past that will inevitably fade away.  Others insist the trend is vindication for the ultimate music showcase, an irreplaceable artistic format.  Wherever your opinion falls on this topic, you can’t talk about vinyl without referencing analog recording.  And if we are talking analog recording, we are talking tape.

So I’ve been asked to write an article about tape speed or ips.  What? Really?  That’s it?  Just ips?  Nothing else?  Hey, who got to do the article on tube amps?  Can I switch with him?  How am I going to do write about IPS without boring the hell out of everyone within reading distance?  Well, here we go…

IPS or inches per second refers to the speed at which the tape on your recorder is moving across the heads.  So, 30 ips means that the tape is trucking along your deck at a whopping thirty inches per second.  Well, that’s about it, see you next issue. OK, just kidding.  I do plan to be brief, but there is a bit more to ips than that.

The questions we want to ask ourselves are: does tape speed matter and what speed should I be recording (and playing back) at?  For the record (pun intended), I believe it is important we include tape format in any discussion about tape speed as the two are directly related.

Tape recorders are manufactured to be setup for a limited combination of speeds and formats, depending on the intended usage.   Most older consumer decks are built to accommodate 1/4” tape & run at 3.75 ips & 7.5 ips, mono, half-track or stereo.   Newer consumer and semi-pro decks will often include 15 ips.  Professional tape recorders have been made to accommodate a dizzying combination of formats and speeds, and can even be modified to operate at speeds and formats beyond the specifications intended by the manufacturer.

For the sake of this article, I’m going to stick to the most common pro formats.  For 2-track stereo, 1/4” and 1/2” at either 15 or 30 ips are considered standard.  For multi-track recording, 2” 16 & 24 track formats are standard, again at either 15 or 30ips.

The general “rule of thumb” governing tape speed is this: the faster the speed, the better the quality, signal to noise ratio, wow and flutter specs and frequency response can be expected. Also, the higher speed will afford you the most precise editing capabilities.  Yes, editing.  Before Pro Tools, that’s how we did it.  You cut the tape.  If you are working on an all-analog project  – something we specialize in at MetroSonic – that is a tool and skill that is still required.  Conversely, the slower the speed, the more music you can pack onto a reel of tape.

If higher speed means better quality and editing, why not just record at the highest speed and be done with it?  Well, that was basically the case for pro recording, and 30 ips was in fact the default standard for many years.  In the days when tape was cheap and recording budgets were huge, tape cost was not an issue.   A single project could have a dozen 2” reels and as many 1/2” mix masters including alternate versions.  Today, tape is a good deal more expensive ($340 for a reel of 2”, $110 for 1/2”) and recording budgets are a fraction of what they used to be.  So now, tape usage is an important consideration, and a slower tape speed may be a compelling alternative for an analog project.

With certain formats, 15 ips does offer some additional advantage beyond economy.  When running 1/4” stereo or 24-track 2”, you will often find an improved low frequency response compared to running at 30 ips.  Depending on your priorities, this could be an additional reason for your producer to have you run the project at 15 ips.   So what are the disadvantages of 15 ips?  The biggest compromise is the signal-to -noise ratio.  Some music projects containing quiet passages or intimate solo sections will only work with the use of noise reduction (like Dolby) at this speed.

In the end, your producer and engineer are best qualified to recommend what speed and format is best suited for your project.  Analog projects at MetroSonic are run almost exclusively 16-track 2” at 30 ips and mixed to stereo 1/2” at 30 ips.  For me, that’s unbeatable in sonic quality and they’re the only standard analog formats that will compete head to head with today’s digital spec.  Because of the wider track widths on a 16-track 2” (compared to 24-track) and 2-track 1/2” (compared to 1/4”), my Ampex MM1200 and Ampex ATR 102 have no problem recording low frequencies at 30 ips, and are virtually flat to beyond 20k.

The next time you have some drums or guitar tracks to lay down, give that format combo a try.  I’m betting you’ll agree, there is nothing that compares. One last piece of advice, if you are buying tape, buy ATR.  It is made proudly here in the USA with precision and care by some very dedicated people.   And no, I’m not paid for that endorsement.

A side note – the speed you record at is not necessarily the speed you have to play back at!  While speeding up or slowing down the tape is not common these days, the concept introduces some very interesting technical tools and artistic options.   Let’s say you have a 3-minute track that you need to fit into a two and a half minute spot.  Of course you can edit it.  Another solution is to speed up the tape and then use a harmonizer to pitch it back down.  Another application is to simply slow down a mix to give the recording more “air.”  This can produce some interesting, sometimes startling results, slightly altering the tone and timbre of the instruments and voices.

Anyway, that ought to do it. Happy recording!

Pete Mignola is a composer, musician, Emmy award winning recording engineer, and owner of MetroSonic Studios in Brooklyn since 1991.  His 30 years of experience recording music spans a wide variety of genres and his work has been featured nationally in radio, TV and film.   A good deal of his recording work is with independent artists centered around the thriving Brooklyn music scene. For more visit https://www.metrosonic.net/artists/artist-list and https://www.metrosonic.net/artists/testimonials.