15 or 30ips?

[student8]

Hello,

Still a little bit 'new' here myself and learning - but I was wondering if any of you could answer this question, maybe in multiple answers:

(I know what these numbers technically 'mean' & stand for, but.......)

1) what 'exactly' is the importance of having to choose between 15ips or 30ips?

2) Is there a 'huge' sound difference between the two (if any?)

3) is it better to use one over the other for a multi-track recorder? what about a 2-track mastering recorder?

4) which is the 'industry standard' or better yet, which one do most of you guys prefer to use & why?


- I've kinda read too many 'contradicting remarks' & such on this topic (from various magazines & books) and seeing how Dr. Zee reminded all of us to 'be very cautious in what you may read' - I figured I might as well just ask this question here, and with also higher hopes that most of you in here seem to know more than any magazine or book I've ever read anyway


- any help on this topic would be great, and much thanks to those of you so far that have helped me out in other threads.

 

[sweetbeats]

1) 30ips pros as far as I know: generally better HF response, lower noise floor. Cons: uses tape faster, risk diminished LF response. If you want to run 30ips you really need to be aware of whether not the machine was really designed to run at that speed. When you double the speed the response curve kind of shifts up an octave and that's why you risk diminished LF response. This article by Jack Endino is a nice overview of different decks and responses between 15 and 30ips. This page over at analogrules.com also does a nice job showing how a head looks inside. Look on wikipedia too or google the subject. The arms of the 'C' of the head need to be long enough to hold the wavelength and at 30ips a 30Hz wave is 1"...that's a big head. And then the profile and design of the face of the head is important too because even if the head can hold the wave it then has to be transferred to the tape. Heads are...important. I'm just learning this stuff on a dialogue over at the Ampex List where we are discussing 15ips vs. 30ips.

2) Only your ears can tell you that, but, as above, the noise floor will generally drop, and HF response will improve. Though I have no direct experience (so beware of my opinion), I'm comfortable stating that the difference will be noticeable. Whether or not it is an improvement is where your ears come in (I refer you back to the Endino article)

3)15ips is more common AFAIK for tracking and for mastering. 30ips is considered a higher standard, but like I said before, you need to be aware that (IMHO) there are probably more decks that sound better at 15ips than 30ips, because I believe there are less decks out there that were built for the purpose of handling audio at 30ips...those are more cream of the crop = more expensive = less of a market share. This topic comes up quite often, this and the whole 1/4" or 1/2" for mastering, and +6 or +9 tape...you need keep in mind that a vast quantity of great music was tracked at 15ips on +6 tape and mastered to 1/4" using +6 tape at 15ips...or tracked using +3 tape...or "0" tape. The gear doesn't make the music...it allows a certain potential, but there is so much that happens before the signal hits tape, yes?

4) Already kind of answered this...If you go by the majority of what is out there and what is used I think you'll find 15ips to be the number. You have to remember what changes in speed do to the response curve. The Tascam 388 is a great example. Narrow format (8 tracks on 1/4" tape) and it runs at 7.5ips but that actually helps to preserve the potential of that relatively small head to carry LF signals...in fact, the "spec" sheet shows the -3dB knee-point on the 388 to be 30Hz! That it impressive for such a narrow format at a lower speed. Tradeoff? Not as good HF response and higher noise floor but with dbx I and high output tape the signal to noise ratio is good and the HF knee point is higher than my ears can hear anymore!

I'll refer to what I always remember cjacek saying in another thread with a similar topic which was words to the effect that you should be completely happy with material mastered at 15ips on 1/4" tape. And it comes back to you with how well the deck is setup and maintained, and how well the material is recorded etc. 30ips isn't a silver bullet, neither is 15ips for that matter. I've heard recordings you would never know were tracked on 4-track cassette at 3 3/4ips...If I'm not happy with how my stuff sounds on the gear I have it isn't the gear's fault.

 

[dodgeaspen]

Welcome to the forum. I would follow the advice that Sweet gave you. It is more cost effective to run in 15 ips. I have never run a deck at 30 to hear the sound diffrence.

 

[student8]

Thanks guys.

I think this has given me a better 'overall' idea as to what to expect or to choose between the two.

I would still like to get your opinions (if not a few more from others) - but for now, i think I'm just going to go with 15ips for my Otari. (and SweetBeats - I did in fact read the 'Jack Endino' article as well. Still, a little confusing to me (to say the least - but I did pick up on a few things, such as the 'hiss' differences - and it seemed that he preferred 15ips, on nearly everything - which is why I think I should just stick with 15ips.

However, (a few more questions)

1) Does the 30ips really give you a lot less 'hiss' compared to 15ips?

2) I went ahead & recorded a couple of things at both 15ips & 30ips, then played them back to A/B them. But I did this just by simply switching the knob back and forth from 15ips to 30ips, and on the 'same tape' as well (I don't know if I was supposed to do it that way or not? - but since I still don't know how to properly 'align' my machine - that was about the only way I knew how to conduct this little A/B test) Is it 'ok' to do it that way?

- But regardless - when I did this test - I honestly (or barely) could even tell a difference, if 'none' at all. Should I have been able to hear a much 'bigger difference' than that?

Any additional answers would be wonderful - and I think I would just prefer for you guys to make this decision for me, because I really think you guys know more of what you're talking about & understand way more than I currently do, you know?

- I trust your opinions well enough to rely on them at this point. I just want to hurry up & get at least this part decided on & done - so that I can get ready to finally order my 'MRL tape' like you recommended & then you guys can start helping me properly align this machine.

(Oh, and I still need to decide on the actual NAB or IEC setting to go with & stick to, before I can order the MRL tape (right?) So again, I think I'd just rather you guys kinda 'tell me' what to go ahead & stick with - because i just don't know enough between the 2 to decide on which one would be the best for me, you know? i think you guys would know that though.

- thanks you so much

 

[miroslav]

What machine are you setting up...is it an Otari 5050?

Here is a link to a scanned copy of Otari Alignment Procedures manual for the BII/BIII 5050.

If you have a different Otari...the actual switches and pots may be labeled differently, but the overall procedure would be the same as in this manual...so it's a good read either way.

Oh...for my MX5050BIII-2 I went with NAB...but that's your call, there's no right/wrong there. NAB has been around for a long time in the USA...so if you need to consider tape compatibility (like if people will be bringing you tapes made on other machines)...NAB is probably the "safer" way to go.
If it's just for your recording of new tapes...you can go either way.

It's how the EQ curve is set...IEC is a bit flatter than NAB...but then NAB has that bass bump that some people prefer, especially for music that has to have lots of THUMP.
There's a bunch of info on the choices.
Talk to John French at JRF Magnetics...that's where I got my MRL tape, and he said go with NAB at 250mWb/m. I used the 250nWb/m but then set my deck at +3 since I wanted a bit more saturation….meaning I referenced my 0VU at -3 (which ends up as a +3 boost when I’m reading 0VU)
(I think I said that right…)
It’s easy to get your head spun around with all the different “references” one can use for setting up a deck!

Anyway…here’s the PDF.
(Every once in awhile the link errors for some reason…but the file is there, just give it a second to download).

http://www.miroslavmusic.com/audio/Otari/OtariAlignmentProcedures.pdf

 

[student8]

No, actually I'm using an Otari MTR-10. (probably close to the same as yours though?)

But thanks for the NAB recommendation - I think I'll just go with that, based upon what you just said.

Do you use 15ips or 30ips by the way? Like I said, I tried just switching the little switch to 15ips for one recording, and then back to 30ips for another one - but i honestly couldn't tell that much of a difference during playback, if any at all. (did i do something wrong? - or is there just not that really big of a difference between the two?)

And by the way Miroslav, when you said you 'set' yours up to be +3 'hotter', so when the VU reads '0', it actually means or sounds +3 hotter (and this may be a really stupid question) - but why not just record 'normal' until the needle actually hits '+3' (slightly in the red zone) to get the same sound effect?

 

[dintymoore]

I used to have a MX5050 - the 8 track version MX5050B I think. I loved that thing, with 996 tape I could record 14 db over without complaints.

Every time you double the tape speed, i.e. you go from 15 ips to 30, it makes everything go up an octave.

This includes the hiss, so when you record at 30 the tape hiss is up an octave from where it is at 15 so you hear it way less. Helps in intros, like when it's just vocals and piano. When everything's pumpin' who knows.

Also, when you record at a higher speed there's more tape surface available for a particular sound so the definition is better.

Bottom line is - 15 sounds good, it isn't a night/day difference to record at 30 ips, but if you can afford the tape and can hear any benefit, why not use it, that's what they put it there for.

 

[miroslav]

Do you use 15ips or 30ips by the way?

No...I'm a 15ips man!

Well...right off the bat, you will use twice as much tape for the same amount of time when running at 30ips...but beyond that, 15ips can sound fatter, and it really depends on the machines (that's what the Jack Endino article shows)….though 30ips can also be magic under the right circumstances.

Don't just switch the speed button.
Record 1 minute of music at 15ips and then also at 30ips...and A/B them.
If you can feed the Playback output and record it back into a DAW (not sure if you have one)...then you can A/B them side-by as two tracks in the DAW, which is easier/faster A/B that way...but you then also add the A/D conversion to the process.

What to really look for, listen for...is the low end and the high end....that's where you will hear any differences between the two.

And by the way Miroslav, when you said you 'set' yours up to be +3 'hotter', so when the VU reads '0', it actually means or sounds +3 hotter (and this may be a really stupid question) - but why not just record 'normal' until the needle actually hits '+3' (slightly in the red zone) to get the same sound effect?

I may not be able to explain this clearly...

If you just crank up the volume for a +3VU reading, you are applying gain to the front-end electronics.
By adjusting your electronic calibration, you change the reference fluxivity level of your machine/tape "making" the tape more magnetically "absorptive" (or is it less absorptive?...or is that even a good analogy???)
With me using a 250nWb/m tape and setting at -3...I'm actually doing my alignment as though I am using a 355nWb/m tape, so when I record, I can hit my tape +3 dB harder and get more tape saturation without overdriving the front-end electronics.

Anyway...

Heck...I understand what I just said but if I explained it poorly...I'm sure someone will correct me!

If you want to get a real headache... read the MRL guide for choosing MRL tapes:

http://home.comcast.net/~mrltapes/choo&u.pdf

 

[dintymoore]

No...I'm a 15ips man! ...15ips can sound fatter,

That's very interesting.

My MX5050 only had 15 ips max I think - man was that thing great on the bass end.

Here's what I thought when I read your comment, and I don't know if this applies:
I'm a drummer, and one of those drummers that got into drum machines when MIDI hit way back. My first drum machine was a Sequential Circuits Drumtraxs in '83 (whew!). I think it was 12 bit (not sure) and the cymbals were pretty wretched... but the kick was way punchier and bottom'y than the later 16,20 and 24 bit samples I've had. Rounder. So was the Linn.

The difference is very similar to the difference between my MX5050 and my Mac as far as bass goes, and I'm wondering if there's a connection.

 

[sweetbeats]

Well, not to muddy things, but I recommend IEC at 15ips. Your MTR-10 is a good deck and I believe it has switchable EQ curves via switches on the control surface. That means you can buy an IEC or an NAB calibration tape and calibrate it to whatever standard the tape is that you buy, and then switch it to the other as you need to. The reason I recommend the IEC tape is that NAB is regarded as somewhat of an old standard...folks in Europe were using the IEC standard and then that finally caught on here because it was a better standard. Jay McKnight of Magnetic Reference Laboratories has a lot to say about NAB vs. IEC. For some transports NAB is very appropriate, but for more contemporary transports, in general, IEC is a more appropriate curve. Jay was not a fan of the NAB curve because of the HF de-emphasis/low-end emphasis...it gets pretty technical pretty quick but maybe you get the jist of it.

The MTR-10 is a pretty advanced transport IMHO with good electronics and whether you get the NAB or IEC tape, I think you'll find you like running it IEC, and because IEC is a more prominent standard I think it would behoove you to get an IEC tape depending on what you may be calibrating in the future that doesn't have switcheable eq curves. That's just how I think...sometimes its a tremendous waste of time. Anyway, like evm1024 said elsewhere, it is completely possible to use an NAB tape to calibrate to IEC and vice-versa...there are conversion charts, but I know I'd be using IEC with an MTR-10, that's the standard Otari intended though it can be changed to NAB at the flip of a switch.

I'd likely be using 15ips. If I had a deck that could do 30ips I'd be checking it out to see what I like better. You've done that and indicated you couldn't hear much difference and so it comes back to tape cost. And I still rely heavily on the ideas presented by Jack Endino in his article. Again, a 30Hz signal wave at 30ips is 1" in length. To accurately record and reproduce that wave, for starters anyway, the pole pieces in the head need to be 1" in length. Then there are all kinds of issues with the profile of the face of the headstack. That makes for a big head...the Otari, and most transports, don't have those kind of heads and that's totally fine, but that's why they roll off earlier as you progress down the audio spectrum in Hz when you go from 15ips to 30ips.

The other thing that I like about the Endino article is that it helped me understand that a transport could be totally flat at 100Hz, 1kHz and 10kHz, but all over the place otherwise, so at 15ips you may have a rise or a dip in the curve that naturally takes care of a problem that you don't even see depending on what tones the calibration procedure for the deck calls for but when you go to 30ips, like has been said, that rise or dip shifts up an octave and may now be causing a problem. Go with what sounds good but I'm happy at 15ips. You have luxury of being able to choose. You could always get a two-speed caliabration tape, or just get the multi-frequency tape and (for instance) a 500Hz tone at 15ips becomes a 1kHz tone at 30ips.

 

[miroslav]

Well, not to muddy things, but I recommend IEC at 15ips. Your MTR-10 is a good deck and I believe it has switchable EQ curves via switches on the control surface. That means you can buy an IEC or an NAB calibration tape and calibrate it to whatever standard the tape is that you buy, and then switch it to the other as you need to. The reason I recommend the IEC tape is that NAB is regarded as somewhat of an old standard...folks in Europe were using the IEC standard and then that finally caught on here because it was a better standard. .

Yeah...NAB is pretty old!

My multitrack is setup with an IEC curve...but my 2-track with NAB.

I may try the IEC on the 2-Track at some point...though I don't think it's a simple as just flipping the switch (my 5050BIII has the NAB/IEC switch). IOW...if you set it NAB, I don't believe that just flipping the switch makes it IEC.
The way I understand the manual for the 5050 is that you first select NAB or IEC with the switch...but you would have to recalibrate for either one, using the appropriate tape.
I could be wrong on that...but that's how I read the alignment procedure in the manual.

Oh...and I don't know how “critical” it really is to decide on NAB or IEC.
I think in the end, it will be up to the deck which it likes better, what mood it’s in ...and then also how you like to generally EQ your overall “sound”.
I think for some music IEC might be the better choice, and NAB for others.
I mean, I just don't think NAB is a standard that must be avoided/discarded....what do you think?

Maybe some folks who are much deeper into those details can chime in.

 

[jedblue]

Well, not to muddy things, but I recommend IEC at 15ips.

Agree, all my machines are IEC @15ips, including the Otari 5050.

 

[jedblue]

The way I understand the manual for the 5050 is that you first select NAB or IEC with the switch...but you would have to recalibrate for either one, using the appropriate tape.
I could be wrong on that...but that's how I read the alignment procedure in the manual.

Yes Miroslav, I've always read it that way too on my 5050. I set all three of my recorders to IEC. Two are European and that's their recommended standard so one reference tape does all three machines.



Geoff

 

[sweetbeats]

"Flipping the switch"...yes, my bad. I should clarify. My Tascam BR-20T has this feature also but it only applies to reproduction. The electronics need to be calibrated to change the curve applied to recordings made on the transport. Does that make sense? It is a convenience feature so that the mastering house could quickly switch between EQ curves when reproducing material from customers which may be recorded on various rated output tape types and formulations and tracked with different curves (i.e. NAB or IEC). I'm assuming the MTR-10 is the same ideology.

Oh...and I don't know how “critical” it really is to decide on NAB or IEC.
I think in the end, it will be up to the deck which it likes better, what mood it’s in ...and then also how you like to generally EQ your overall “sound”.
I think for some music IEC might be the better choice, and NAB for others.
I mean, I just don't think NAB is a standard that must be avoided/discarded....what do you think?

Yeah, I agree. I'm just making some assumptions based on what I know if the MTR-10. You are absolutely right IMO about not "discarding" NAB EQ and that's why I encouraged Student8 to go for what sounds best but MRL tapes ain't cheap and it is more likely that IEC is what is going to be used since that's the standard upon which the MTR-10 was based, and worst-case scenario if he likes NAB better then he can still use the IEC tape to cal the deck to NAB using conversion charts. More advanced stuff but he really seems to be chomping at the bit to get his MRL tape.

I'm going to covert my 1" 8-track Ampex deck to IEC (likely...going to do just 2 channels and A/B with NAB channels), but you are very right to link the transport "personality" to the curve...tape too. Advisement I received on whether to stay NAB with the Ampex or go IEC was more the same of what we've heard: IEC will be flatter and more acurate reproduction..."cal that Ampex to NAB @ 15ips and 250nWb/m and it'll sound like an Ampex for sure." I love that.

 

[miroslav]

Yeah...I was on the MRL website checking out the conversion tables that you can use if you have one kind of tape and you want to set up your deck to a different reference tape.
I did that with my 250nWb/m tape and used one of the conversion tables to set the 2-track as though I was using a 355nWb/m tape.
Not a big deal.

I also looked at the IEC <---> NAB (and also the 15ips <---> 30ips) tables, and while they didn't look too complicated, I'm wondering if it's just easier and worthwhile having both an NAB and IEC tape...?

To me...this all comes down to the same kind of of questions/debates people have about mics, preamps..etc.
Should I get the "transparent" preamp or the one with plenty of color...???

I don't think there is a right/wrong answer...you just learn to work with either one...and think kinda' the same goes for NAB or IEC curves.

Do you agree?

 

[sweetbeats]

To me...this all comes down to the same kind of of questions/debates people have about mics, preamps..etc.
Should I get the "transparent" preamp or the one with plenty of color...???

I like the transparent ones because then you can see all the guts inside of it...I liked it when they did that with pushbutton phones back in the 80's. Those were sweet.

I don't think there is a right/wrong answer...you just learn to work with either one...and think kinda' the same goes for NAB or IEC curves.

Do you agree?

yes and no because it depends on the deck. If you are using a deck designed around IEC and if its electronics aren't that robust you could potentially overtax the electronics where you wouldn't expect it if you run NAB because of the LF emphasis. Sort of an obscure possibility but I think its important to not that it isn't just "what flavor do you like?"

I also looked at the IEC <---> NAB (and also the 15ips <---> 30ips) tables, and while they didn't look too complicated, I'm wondering if it's just easier and worthwhile having both an NAB and IEC tape...?

Sure if you've got the money...But I can certainly see it being easier to use the tables if you are familiar with the calibration process and the table itself rather than cough up for another tape, especially if you are running 1" or 2".

 

[miroslav]

I guess I was thinking about my 5050 when I used the "flavor" analogy since it offers both NAB and IEC, though this particular deck was set up for NAB from the factory as the "default" setting.

You are right...looking at the conversion tables again, it's not too messy, but since it's only about $150 for a 1/4" MRL tape...who knows, one day I may pick up an IEC version for my 5050.
The multitrack is IEC...I wouldn't bother trying to "convert" it to NAB.

Oh...and I always really loved the transparent motors they would have at the car shows!

 

[Beck]

15 or 30ips?

I prefer 15 ips for tracking and mastering... always have. 15 is the sweet spot for me. Generally speaking you get better signal-to-noise with 30 ips, but even that depends on the machine, tape, electronics, etc. 15 ips can be pretty quiet, and if your particular machine is a little noisier than you like you can use noise reduction.

As already mentioned the cost of tape is more of a factor than it used to be. I’ll probably never run 30 ips for that reason alone.

Sonically speaking, 15 and 30 may have different qualities, but I wouldn’t say either is better or worse. I guess from my perspective there’s no compelling reason to run at 30.

 

[miroslav]

... and if your particular machine is a little noisier than you like you can use noise reduction.

...or hit the tape a little harder using a higher flux level.

Like for 911 tape...MRL recommends 250nWb/m for systems with noise reduction and 355nWb/m for systems without NR.

 

[student8]

Lots of good points & very helpful info as well guys - I really appreciate everything you've guys posted so far. 'Thanks'.

By the way Sweetbeats - you mentioned that my Otari MTR-10 was originally set-up for IEC - but when reading thru my manual earlier today - it says in one area that they 'recommend' using MRL tapes set for NAB.

(Granted, it also says that it's 'switchable' as well) - but with that said - does this mean I better stick with 'NAB' over 'IEC'?

Also, a few other things to mention: when reading the part about 'setting up for alignments' - it has a 'requirement' list of things I 'must have' before doing any alignments.

One of the things it says I must have, is something called an 'extender board'. Have you (or anyone) know what this is? I've never heard any of you ever mention one of these before.

Another thing it mentions (as far as using or selecting a 'tape' to record on) is either 'Scotch 226' or equivalent. I've never even heard of 226 tape before. But more importantly, what is today's 'equivalent' for that tape? - or is it all that important to stick & use that particular tape anyway?