English, please.....

[student8]

Ok,

I'm going to attempt asking this question in this forum, in higher hopes that I'll get some feedback in 'simple terms' that even I can understand!

I'm simply trying to figure out 'what is the main difference between NAB and IEC eq'ing?'

and what could also be added to that question, is:

2) do you need to 'choose one' for your r2r and pretty much just stick with it?

3) is it really that big of a sound difference?

4) is it really a major necessity to keep it constantly 'aligned' within your r2r?


- I'm honestly not trying to come off as any type of a 'smart-a@@' at all - I'm only trying to ask these questions in the most 'easy to understand' way that I know how to. I'm still quite 'fresh' in the area of analog recording, and trying to learn all I can from those of you who know way more than I do, so bear with me if I come off sounding like a complete idiot with anything (I probably am at this point

- seriously, any help in this area would be great, and again, just please try to keep all answers and/or replies as simple as possible here. (most other forums where I've asked this exact same question, come off sounding like Stephen Hawkins speaking swahili thru a delay pedal.)

[Dr ZEE]

here: http://home.comcast.net/~mrltapes/choo&u.pdf, take time reading the whole damn thing. it's all in english
In very short and in respect to your subquestions: it's all about interchanging.

[evm1024]

Don't sell your understanding short. There is a learning curve to all this stuff so don't worry. it will come to you.

NAB and IEC are simply 2 differing ways of getting the most out of tape and tape heads. Physics set some limits on how tape accepts a recording source.

The music we want to record has tones from the lowest to the highest. Our goal is to record those to tape and get them back faithfully. If we assume that the peak volume of each of those tones from the lowest to the highest was the same (loud) volume and recorded them straight to tape that way physics makes some of the tones hit the tape harder then the others. This would cause overloading at some tones and under loading (not getting the best playback at others).

To deal with this some crafty engineers from the '50s came up with a scheme of boosting some tones (tone ranges actually) and reducing others before recording. (If you boost the highs and lows it is the same as reducing the middle...)

In effect this "EQ curve" made our music print to tape with each tone recording at the "best" level. Of course the Americans and Europeans went about it in differing ways to get NAB and IEC EQ.

If you on playback just played it back without doing anything you would hear quite plainly that someone was screwing with the levels at each tone band. It would sound sucky. So on playback those same boosts and cuts are applied again except that the boosts become cuts of the same amount and ditto cuts become boosts. This is the opposite of what was done on recording. Thus canceling out the recording EQ and giving a faithful playback.

Hope that helps....


Q2) Generally you do not get to choose which one until you get to "higher" level decks. THe BR-20 for example can do both but (almost) all 1/2" 15ips 8 track decks are IEC. You do not have to stick with one or the other in a general sense. But you will hear differences if you mix them (play a NAB recorded tape on an IEC machine for example). IN practice NAB recorded tapes on a NAB machine sound just as good as IEC on an IEC machine. I tend to use IEC where possible because I think that the >>>theory<<< behind it "should" give better results in some cases.

3)No there is not a big sound difference expecially for home recording. ?

4) Alignment is for 2 reasons. The first is to get the most out of tape as possible and the second is so that your tapes will sound good next year. (and on other decks)

If for example you never aligned your deck you would be recording to a "standard" alignment. Your standard. Then as time goes by the alignment of the deck shifts. And so does your "standard". Record today and playback tomorrow and there is almost no shift so all is well. But then years down the road you dig out a tape you made and spool it up and it sounds like crap. Plus because you were in effect using "your standard" you could not get back to that alignment with any accuracy.

If on the otherhand you did align to NAB or IEC you could take that same tape (or one I made) and it would playback on an aligned deck quite nicely.

You may have heard about test tones. In more professional applications or more serious home recordings youu wold record a series of test tones on the front of the tape. These test tones tell some future engineer most everything he needs to know about the alignment of the deck that made the tape. They give head azimuth, recording level and EQ information. This would allow the engineer to set his playback alignment to what is actually on tape.

Dr Zee gives you one of the best resources on EQ in the world (if not the best). Take your time to read it and don't worry if it sounds like Sumarian. That learning curve is steep at first. Hopefully my little posting here will give you a step up.

Regards, Ethan

[Dr ZEE]

I don't mean to argue neither do I mean to pick on words , but I simply want to highlight again, that these standards have nothing to do with "sound quality" per say, neither do they have anything to do with "getting the best out of tape".
These standards are all about one and only one thing, which is: ensuring the precision of interchange, or to put it differently - it's about "preservation" of the recorded material during the interchange, or to put it differently - it's about minimizing modification of the recorded material, that may be introduced by the interchange.

In a sense it is like a language. English is a popular "standard" for interchange of ideas and opinions .
Makes sense?

[student8]

Ok!

(whew!.........

First off, thank you guys for your nice 'laymen-term' input on this subject matter, and also helping to explain it in a much more 'easy to understand' way. (man, does that help!)

so first, let me see if I got most of the 'basics' here correct:

* NAB & IEC are for the most part, just 'personal preferences' and/or 'industry standards?'

(I'm still a little confused from what I read about 'AES/IEC2' (it says it's basically the 'same' as NAB, which is what kinda confuses me. Why not just still call it 'NAB'?)

However, it sounds to me like this thread is about to go into a slightly different direction from here, so again, bear with me here & I hope you don't mind a few more questions from me?

If I have this correct, you really need to decide upon a MRL tape - before - you really ever decide on what type of tape, speed, & EQ to use (correct?)

So let me just start off by telling you what kind of deck I have first, and then we'll go from there.

I'm using an Otari MTR-10 deck, 2-track, that's set-up to play 1/4-inch tape/reels (10.5"). (it also gives you the choice for 7.5, 15, & 30 ips - plus NAB or IEC) - as far as the 'ref flux' goes - it allows the choice between 'hi, mid, & low'.

(hope this additional info helps any?)

Ok, here's some of my additional questions that I think may help me even more, if I can get some help from you guys (and again, try & keep all answers as 'simple' as possible - because I really want to get all of this right the first time, especially before going out & buying the wrong tape, or an expensive, incorrect MRL tape!!


1) Seriously, which of the two formats do you guys think would work best for my machine? - NAB, or IEC (or any of those others?) I'm completely open on any opinions here.

2) (this may be a dumb question), but if 30ips is the 'best' overall sound quality, then why exactly would I even want to use 15ips or below? (I only ask this because the MRL site basically says I need to make a choice before ordering anything from them.) - Unless you can tell me otherwise, I was planning on recording everything at 30ips, in order to get the best quality. (I could really care less about preserving tape length.)

3) Due to the 'expense' of these MRL tapes, it sounds like I'll probably only be able to afford just 'one' for now - so with all the details & info I've given of what machine I'm using & whatnot - seriously, what would be the best 'all-around' MRL tape I should get, or that would cover the most 'area' (if that makes any sense?) - again, the only reason I ask this, is because the MRL site seems to offer several types of these testing tapes (and are pretty pricey individually, if you know what I mean? - examples: 'multi-frequency' tape, 'pink/white noise' tape, 'short chromatic sweep' tape, '3150-Hz Flutter and Speed Test' tape' - etc, etc, etc - (sorry, but this part is extremely confusing to me (and I did read it probably 3-4 times over) yet, i still have no idea of which tape I should buy for myself, you know? (and please tell me that I don't have to buy each one - I'll have to mortgage my house!!)

4) and last for now - my Otari unit has a 'Test Osc' (and 'Ext OSC' output) on it, which basically reads: 'line, 100hz, 1Khz, 10Khz,' & so on... - What exactly is this feature, and, could I just use this feature for these 'alignments' instead of a MRL tape?

Anyways, I'll let you guys take over from here - but I just really wanted to ask all of this first, before making the big mistake of buying any 'incorrect' product. And again, thank you guys so much for your knowledge, input, & advice so far in this area. You guys have already been way more helpful than any of those other forums who actually talk 'down' to you like you're wasting their time, and speak 'tech-greek' anyway I'm already starting to learn a few things, just from you guys alone.

- Thanks again for the help.

[Dr ZEE]

As for general blah-blah in respect to standards and alignment, I can't add anything else. The MRL .pdf document actually makes it all pretty clear.

As for more specific questions, I personally don't know a single practical thing about otari machines, as I never had one, so I would not even try .
One thing I can tell you, though, that this machine is designed to enable a user NOT to just accomplish a task, such as just recording and playback, but to enable the user to serve customers and to accommodate various specific technical situations, that's why it has "special" options and features.

Do you have mtr-10 service manual? You want one
If you don't, I've found this page: http://www.audioschematics.com/otari.html , looks like there's rar file there (scroll down).
I don't know much about how to decompress/open .rar files, never happen to deal with one, but here is the page with info: http://www.tech-pro.net/howto-open-rar-file.html

[ofajen]

I'll skip the physics and point out that most magnetic playback heads, due to the way they work, play back a "constant" flux level on the tape with a 6 dB/octave rise in response. So, the playback electronics has a 6 dB/octave low pass filter to compensate. The eq curves throw in a wrinkle: they say that we all agree to filter the record input with a 6 dB/octave filter above an agreed frequency and put that signal on the tape. So the playback amp has to have the low pass filter characteristic up to that frequency and then be flat above that. If you get the curves right on both ends, everything works out.

IEC1, aka IEC aka CCIR, uses a higher cutoff frequency on record and playback eq than NAB. That uses up more high end headroom on the tape, which is OK, and produces better signal to noise at 15 ips than NAB.

NAB also has a record signal bass boost below 50 Hz and compensating cut on playback. That was evidently helpful in controlling low end noise fifty or sixty years ago, but these days it's just a waste of low end headroom and can cause low end distortion. IEC1 will generally be much cleaner on the low end.

I'm biased, no pun intended. I'm solidly in the IEC1 camp.

I assume your Otari has a simple adjustment to use IEC1 at 15 ips. Some decks require soldering a jumper or even making small mods to the circuit to do IEC1.

At 30 ips, there is only AES, which is the same as IEC1 at 15 ips on a wavelength basis (cutoff is twice as high and no NAB-style bass boost on record), so you can cheat and use the same calibration tape for 30 ips AES and 15 ips IEC1 without any complicated table of level adjustments, you just need to realize that the frequencies of all the tones are doubled at 30 ips.

Hope that helps.

Otto

[ofajen]

Originally Posted by ofajen

At 30 ips, there is only AES, which is the same as IEC1 at 15 ips on a wavelength basis (cutoff is twice as high and no NAB-style bass boost on record), so you can cheat and use the same calibration tape for 30 ips AES and 15 ips IEC1 without any complicated table of level adjustments, you just need to realize that the frequencies of all the tones are doubled at 30 ips.

I should have mentioned... if you do this, I recommend getting the 15 ips IEC1 tape and using it for both speeds. That will give you normal frequencies for 15 ips and doubled frequencies at 30 ips, which makes the most sense, I think. 30 ips usually has better high end and the low end rolloff is also higher, so you won't miss the lowest end tone too much at 30 ips and then you get high end tones out further where the machine should also be putting out more extended high end at 30 ips.

Cheers,

Otto

[evm1024]

as Otto says get the IEC (IEC1) TAPE AT 15 ips. You will want the multi-frequency tape. You should decide on a reference flux for your MRL and get that. The manual will tell you what flux the machine is normally calibrated at. Most likely 320 nW/m ( nano webers per meter).

As Otto said you can use this MRL to cal at other speeds. In fact with conversion tables you can use this tape to cal to NAB, at different speeds and at different flux levels. It is all in the conversion tables.

30 ips vi 15 ips.... I think you should give 15 ips a try. 30 ips has extended highs and on many machines loses the bottom octave. There are some charts showing this for many machines. Let your ears do the deciding. Of course 30 ips eats tape twice as fast which means you need twice as much of it and that you get less per reel. Perhaps even running out of tape mid song if you don't keep track of it.

REgards, Ethan

[student8]

I see.

So let me see if I got some of this correct so far:

1) You guys are basically saying that IEC1 is the 'better' (or preferred) way to go with my machine? And that it will also help 'tighten up' the bass (less 'boom'), 'less floor noise', and also 'slightly extend' the higher frequency ranges as well? (is that correct?)

2) And am I understanding you correctly on this?: You're saying to go ahead & pretty much 'stick' with 15ips over 30ips? - and by also doing this, the overall 'sound quality' at 15ips is not that much of a 'sonic' difference vs. 30ips? (am I correct on this also?)

(I had always heard that recording or playing back anything at 30ips was the best sound quality possible - period. - but i assume this was just a 'myth' or something?'

3) And as far as which MRL tape to get, you're basically saying to go with the 'Multi-Frequency Tape'? - and did you also mention to get the 'Reference Flux' tape as well? -or- did you mean to just get the 'Multi-Frequency Tape', and just use it to also correctly set the 'ref-flux' levels with it as well? (sorry, I got a little confused on that part

4) (last, but not least) Did any of you ever figure out what that little 'Test Osc' switch on my machine was used for? Again, could i just use this for my 'testing' purposes, or do I still need to just buy an MRL tape in order to do all of this?

(I'm still trying to figure out what this 'Test Osc' thing is........)

(and by the way ofajen - 'yes', my Otari machine does in fact have a 'switch' to allow you to select the IEC1 between either 7.5 or 15ips (however, whenever I select the speed knob to 30ips - the display shows neither IEC1 or NAB - it's just blank at that point.)

- once more, i really appreciate the help here guys. If I can get those remaining questions above answered and/or confirmed from you guys - I think i might be on my way!!

- seriously, 'thanks' again btw...

[ofajen]

Originally Posted by student8

3) And as far as which MRL tape to get, you're basically saying to go with the 'Multi-Frequency Tape'? - and did you also mention to get the 'Reference Flux' tape as well? -or- did you mean to just get the 'Multi-Frequency Tape', and just use it to also correctly set the 'ref-flux' levels with it as well? (sorry, I got a little confused on that part

You only need one tape. I agree with the recommendation for the multi-frequency tape. However, MRL needs to know how strong of a flux you want the tones recorded at. That can range from as low as 185 nWb/m for older tapes and recorders up to 500 nWb/m for newer tapes and recorders. It's referred to as the "reference fluxivity."

You play back the first reference tone (usually at 1 kHz) and set your playback level to show 0 VU and then you can calibrate the playback at various other frequencies. Then you know the playback side is accurate and you can trust it to help you calibrate the record side at various frequencies.

It makes sense to use what Otari recommends, which will probably be in the range from 250-320 nWb/m.

Cheers,

Otto

[ofajen]

You might as well try out both 15 ips and 30 ips and see what works best for you. You may want to record some things at one speed and some at the other. I guess one main point I was making is that some of the prejudice against 15 ips really is just due to the shortcomings of the NAB eq, so it's worth giving 15 ips a try.

Of course, the huge irony here is that while I extol the virtues of IEC1, I've sold off the big old machines that ran IEC1. I only have two machines left, a 3M M-23 1/4" 2-track that is nearly operational and a Teac A-3340S that is operational. The Teac hasn't seen much use lately but is about to. Both are both designed to run NAB at 15 ips. I think I can mod the 3M to run IEC pretty easily or just get 15/30 cards and install the parts I have to upgrade the transport to a 30/15 ips belt drive. I think the Teac will stay an NAB machine, at least for a while.

Cheers,

Otto

[evm1024]

On Page 4-3 of the manual that The Good Doctor pointed you to it says that MRL tape 21J205 is recommended for 15 ips calibration (ERROR don't use this tape!). This is the tape to get. You can use it to calibrate the other speeds later. Plus it is quite resalable. (250 nW/m ref flux)

Low flux is for 185 nW/m (good for older tapes), med flux is 250 nW/m (Ampex 456 and the like) high flux is 320 nW/m (Ampex 499, GP9 etc). Of couurse you can hit a tape harder or not to get the sound that you want.

Given the questions you are asking (we have all been there....) I assume that you do not have any significant electronics background. Calibration of a deck can be quite involved and use some equipment that is not in every garage (scope, ac voltmeter that goes flat beyone 20 kHz and tone generators). Hope you have a friend to help you along. And in any case if you keep at it you will learn how to do it.

You might want to post your location in case there is someone nearby who can act as a reference.

Those test osc are for quick tests, minor calibration and printing test tones to a tape to document the state of your machine at the time you made the tape. (It is in the manual)

Regards, Ethan


PS looking over the MRL list it appears that Otari made an error in listing the MRL to use. See here: http://www.jrfmagnetics.com/mrltapes.html

21J205 is the 15 ips NAB (aka IEC2) tape that Otari should have listed.
21J203 is the 15 ips IEC1 tape that you could use. RTFM to verify that calibration in NAB also calibrates IEC1 (as is common)

Look here too: http://home.comcast.net/~mrltapes/pub101.pdf

[Tim Gillett]

Originally Posted by student8

4) is it really a major necessity to keep it constantly 'aligned' within your r2r?
[/B]

Not sure if this is covered but basically whether your machine has IEC or NAB or both, they dont need aligning as a normal thing. They're fixed in the electronics and dont go out. Only if there's an electronic fault like a capacitor gone out of whack will there be a problem with the IEC or NAB part.

Vinyl records and before them 78's had the same sort of thing to try and cope with the noise and distortion inherent in analog recording means.

So on vinyl, they boost the highs in recording to mask the hiss you hear on playback. Same with tape. The risk is you will overload that band of sound when recording.

As already touched on, with NAB, an American development, they were also wanting to mask the hum in the early tape machines' playback. So they boosted the bass in record to mask it. Trouble was that ran the risk of bass overload.
Whereas the Europeans' IEC didnt do this. I believe part of the reasoning was the Europeans liked their big pipe organ music which had very deep bass notes which were already loud and tended to distort with the NAB bass boost in record.

All eq curves like this area all about avoiding noise and distortion in the recorder. They're only ever an approximation as they are trying to guesstimate what sort of spectrum of sound is likely to be recorded, and of course that varies between different types of speech and music.

For example, a piano generally doesnt have a lot of energy in the treble range and so strictly neither NAB nor IEC would be ideal. Some recording engineers used to deliberately add even more treble boost at the recording session, and then cut it off the same amount in playback, giving less hiss in the final product. These guys knew what they were doing. Trying the same thing, guys with less understanding were likely to get into trouble.

In many ways the later noise reduction systems like Dolby and dbx took this a big step further because they changed eq and levels in a dynamic way (constantly changing in response to the music) in both record and playback, so that there was much less risk of running into either tape noise or tape distortion.

Of course with digital audio recording techniques there is no noise equivalent to analog recording noise (except analog noise in the electronic circuitry which is much less of a problem anyway) and so the complexities of things like IEC, NAB, RIAA, and indeed compander noise reduction are not needed.

Hope this helps. Tim

[student8]

'Yes', a LOT of this info from you guys has really helped. I really do thank all of you for your help and input on this topic. (this forum is already way better than most of the others I've tried!)

I know it's going to take me a little while to really 'understand' all of this - but I'm trying my best to take each thing 'one at a time', and 'slowly' at that.

And also, if you know the 'exact' type of 'tools' I'll be needing for these 'alignments', calibrations and such - please let me know, and I'll see if I can find them for a 'cheap' price on Ebay hopefully.

I don't really have anyone in my area to 'help me' as one of you put it - but I am 42 years old, and certainly willing to 'try' & learn. To be honest, I'd rather learn it 'myself' anyway, so that I can hopefully do this again & again in the future for myself - vs. having to locate & pay someone to come out and do it for me each time, you know? - Plus, I'm sure if I have any questions in doing it, you guys can hopefully 'help me' with that as well (if that's ok with you guys of course?

So just let me know exactly which 'tools' or pieces of 'testing equipment' I'll be needing (or just post some links from Ebay on here if you find any, especially at a very 'reasonable' price if you don't mind! and I'll start from there. (gotta learn sometime, right?)

Oh and by the way (a little off-topic here) - but I was just given a few reels of old 1/4" (10.5") ampex 456 tape that is 'used' & has already been 'pre-recorded' on - but my question was this:

"Can I just simply 'erase' these tapes and use them for my machine (the Otari) for now? (until I can afford some 'brand new tape'?)

- and also, "would it be better to just run them through the Otari on 'REC' to erase them, or actually buy one of those 'bulk tape erasers' to erase them instead? (and if so, which 'bulk tape eraser' would any of you recommend for me to buy & use?)

- or- should I use one of those larger, 'tape degausser' machines instead? (again, 'if so' - which type of machine should I look for, an/or 'what features', etc?)

- thanks again guys,

[jedblue]

In regards to the old tape, be careful. Don't assume it's any good and it could do your deck a lot more harm than good if you put it on your machine at all. Reading the sticky tape thread at the top of the analog forum http://homerecording.com/bbs/showthread.php?t=228067 will tell you why.

Much better to buy a new reel of RMGI SM911.

There's another thread that lo-fi's been running that goes into great details about the tools you'll need.

http://homerecording.com/bbs/showthread.php?t=286745

Cheers

Geoff

[evm1024]

I assume that you have downloaded the decks manual and some of those MRL pdf files.

Just spend some time skimming the manual paying attention to the calibration procedures and operations stuff. Let it soak in and ask questions when you need to.

Lo Fi's thread is the place for test gear.

a\As was notes look out for sticky tape. A known good tape would keep you out of trouble.

Regards, Ethan

[ofajen]

Originally Posted by Tim Gillett

Not sure if this is covered but basically whether your machine has IEC or NAB or both, they dont need aligning as a normal thing. They're fixed in the electronics and dont go out. Only if there's an electronic fault like a capacitor gone out of whack will there be a problem with the IEC or NAB part.

It's interesting to note the contrast with the pro studios back in "the day", where some engineers were so meticulous they might even calibrate for each new reel of tape, and if not, then certainly with each new batch and each session. Of course, I'm thinking of a time when machines had either one, two or three tracks, not 24.

I recalibrate (or at least do a quick check to see things are reasonably close) every time I switch tape formulations, before an important session and every so often if it's been a while. OTOH, it's amazing how things can be a bit off with a good tape machine and it still sounds good. YMMV.

Cheers,

Otto

[Dr ZEE]

Heh heh, you should choose your user name as student42 , then
Also, "learning yourself" actually is the only known form of learning out there.
***********
Thise seller has all three tools that you want to have if you going deeper into "this stuff" - generator, oscilloscope and a nice and "appropriate for the task" ac meter, here's link: http://shop.ebay.com/merchant/radiom...Q_fromZQQ_ipgZ,
of course there are other different units out there and work-arounds, but the above are as example.
The test/alignment tape itself is a must-have and no way around it if you really want to do it by the book and by standard.
Service manual for the specific machine you are working on is another must-have "tool", and there's no really practical way around it.
*********
Read all the MRL Technical Papers Available here: http://home.comcast.net/~mrltapes/ , add this page to Favorites for a while

Separate in you mind two things:
first: analog tape recording equalization and second: equalization standards, as these are not the same "thing", the first is a "process" and the second are starndartized "formulars" of the first, the purpose of which is to enable "succesful interchange" of the material between recorders and reproducers.

One more thing. Never take anything that you read on any forums/b-boards/in articles and even in "technical papers" as gospel nor as thruth. No exceptions

"It is a miracle that curiosity survives formal education."...A.E.

good luck

[sweetbeats]

Mr. Student...well, I'm 38 and I have pretty well figured out how it works.

I don't really have much to add but I can tell you folks here really helped me get my head around what the calibration thing is all about which is:

1. Making sure that "0" going in is "0" going out when monitoring your deck's inputs...this includes calibrating your meters with an input signal of a known level.
2. making sure that the repro level and response curve is flat at least within the deck's specs...this simply means making sure that the reproduce levels are consistent track to track and match your "reference level" (i.e. "0")...this took me the longest to get my brain around...this is where you get into what reference fluxivity you are going to use. See, nWb/m (fluxivity) is a way to measure the magnetic "strength" if you will of material captured on magnetic tape. Typically if you are using +6 tape (like 456 or SM911) you cal the deck to 250nWb/m...you are setting the deck up so that "0" on the VU meter equals a magnetic strength of 250nWb/m printing to tape. You can use any reference fluxivity test tape you want (within reason). It just may mean you adjust your "0" during calibration. Let's say you had a 320nWb/m tape but you wanted to set the deck up for 250nWb/m operation...then you would set your meters to (IIRC...there's a table somewhere...) +2VU when reproducing the 1k tone (See? The 320nWb/m tone on tape is stronger than what you want "0" to mean on the meter since you want "0" to be equivalent to a magnetic "strength" of 250nWb/m...hope this helps sort out the whole nWb/m thingy. Likewise you could use a 185nWb/m test tape and set the deck up for 370nWb/m operation if you like...your MTR-10 is cool and was designed for a master engineer who would be faced with master tapes of different reference fluxivities which is why you can switch the reference level...it keeps the operator from having to remember what "0" means because you can switch what "0" means to match reference level that was used on the mixdown deck that was used to make the master. To digress further, don't confuse the "output rating" of a certain kind of tape with reference fluxivity. Remember, reference fluxivity has to do with answering the question "What does '0' mean?". The output rating of a certain kind of tape (i.e. 406 is a +3 tape, 456 is a +6 tape, 499 is a +9 tape, etc.) simply means how hot a signal (how much fluxivity) the tape can handle before reaching 3% distortion. Now we can talk about how the reference fluxivity to which you set your "0" relates to the tape...if you set your deck's reference level (the "0" on your meters) to be for +9 tape and then run +3 tape and still reference "0" as "0", you are going to be well into higher levels of distortion...maybe you like that. But the point is to understand what setting the reference level means and why it is important to have some idea of what tape type you will be using and what kind of performance you want out of it so you can set the deck up accordingly. Back to the global view of the calibration procedure...
3. Once the reference level is set along with the input and output levels then you get ready to do the record levels and record response and the first step to that is setting the deck's bias.
4. Then you can record tones and check levels and response.

And don't forget, of course, that prior to doing any of the above you want to make sure that your deck's azimuth is set and that the tape path is mechanically aligned.

Get that manual if you haven't already.

[Dr ZEE]

one more thing:
Stay away from "The art of sound reproduction" By John Watkinson.

Or reed at your own risk.

/later

[Dr ZEE]

I could just ignore this, and maybe I should of, but, sorry guys, this just drives me nuts ..grrrrrrrrrrrrrrrrrr

When I read "shshsh......stuff" like this:

Originally Posted by Tim Gillett

....

All eq curves like this area all about avoiding noise and distortion in the recorder. ....

For example, a piano generally doesnt have a lot of energy in the treble range and so strictly neither NAB nor IEC would be ideal. ...

In many ways the later noise reduction systems like Dolby and dbx took this a big step further because they changed eq and levels in a dynamic way (constantly changing in response to the music) in both record and playback, so that there was much less risk of running into either tape noise or tape distortion.

Of course with digital audio recording techniques there is no noise equivalent to analog recording noise (except analog noise in the electronic circuitry which is much less of a problem anyway) and so the complexities of things like IEC, NAB, RIAA, and indeed compander noise reduction are not needed.

Hope this helps. Tim

Well, Tim, NO! No it does not help at all, because a complete Nonsense have never nor ever could help anybody in any way.

Equalization in analog tape recording process is not a "noise reduction" scheme. (even though it may and does affect signal to noise ratio of the reproducer)

In analog tape recording Equalization Standards (or any non-standard equalization scheme) are not "options" possibly providing "ideal ways" to record a piano, a flute, a big old drum or a dogs' bark.

"NAB and IEC" are not ideal for piano? Do I hear you right, Tim?

This is not even funny anymore.

You see, guys, people who read books like "The art of sound reproduction" and similar and then "speak out" from a position of an "expert" are , may I say, - DANGEROUS.
And many of those people ending up writing books too.

So , again: READ B-BOARDS (and books!!!) with extreme caution!!!!!!!.

/later

[student8]

Thank you Dr. Zee for both the new 'student42' idea , and for correcting that last post by Tim.

(sorry Tim, and certainly no offense, but your post did throw me off a little bit, especially when compared to everything else that I've read in here so far by these guys.)

And special thanks to 'SweetBeats' as well - your last post there really seem to make a lot of sense to me with the way you put some of it. I'm still a bit 'nervous' when it actually comes time for me to make these calibrations and adjustments here soon, but that extra info you added seemed to really 'click' with me for some reason.

(However, I still think I may need you guys help a little, when it comes time for me to 'physically' do the alignments & calibrations - if you don't mind of course? - just to be on the 'safe-side'

And by the way - when it comes time to do these adjustments - are the actual 'step-by-step' instructions in the Otari manual, or do they come with the MRL tape itself?

(Unfortunately, I don't have the original manual for this Otari-MTR-10, but I'm going to try to find & download one here, right after this post.) and also, are there any good 'videos' or whatnots out there which actually show you step-by-step on how to do all of these adjustments & calibrations? - or am I pretty much just on my own here!

And last but not least - the only reason I brought up the question about 'erasing tapes' with a 'degausser' or whatever, was mainly because I still haven't really decided on a certain 'tape' to go with so far. And again, since this machine was just given to me - I have no idea or way of knowing what type of actual 'tape' was used on this machine before I got it. So in a way, I just figured that since I had to do all of these calibrations, alignments, etc - I might as well 'choose' a good tape to use & pretty much 'stick with', if you know what I mean?

So again, if anyone has any recommendations, opinions, etc - on which 'tape' to go with (especially before I calibrate & 'set' this machine up) - please feel free to share any thoughts on that as well.

(and again, the only reason I mentioned the part about 'erasing' tapes - was because i thought that may be a decent way to try out & 'sample' some of these various tapes out there - and without the major expense of having to buy each one 'brand new' - that's all.)

But if you guys think that I just need to completely 'stay away' from a 'degausser' or 'bulk-tape-erasers' - then just let me know that as well. I certainly don't want to screw anything up with the Otari.

- but i was also told that by 'erasing' tapes, you could save a decent amount of money by re-using them again and not having to buy a 'new' tape each time you use one up. I still plan on reading the above links one of you posted (about 'tape shredding') - but is this true in any way? - and do any of you guys 'erase' tapes for these same reasons?

(again, - just curious, and I'm still 'learning' here - don't think I'm going to run out and do it!


(p.s.) - Oh, and by the way Dr. Zee - you mentioned that I would need 3 tools (or 'proper equipment') in order to do all of my proper alignmenets & such (correct?) - generator, oscilloscope and a nice and "appropriate for the task" ac meter

Besides the ones you showed me on Ebay - can you tell me the 'actual names' or 'technical names' for each one that I'll need? (in case I can't win these?) - or in other words, "what 'type' of 'oscilloscope' will I be needing for example? (I hear that there are many different models & types out there.) Same goes for the 'generator' & 'AC meter'. - this would help me a lot. (thanks again)

[Tim Gillett]

Originally Posted by student8

Thank you Dr. Zee for both the new 'student42' idea , and for correcting that last post by Tim.

(sorry Tim, and certainly no offense, but your post did throw me off a little bit, especially when compared to everything else that I've read in here so far by these guys.)

No offense taken.

IMHO emv1024 and Ofajen are very knowledgeable in this area. AFAIK I agree with all they've said here in response to your questions.

What was it about my post that threw you?

Cheers Tim

[student8]

No big deal really Tim,

It was mainly just the part about not using NAB or IEC for 'piano' (or any other certain 'instruments') that threw me a little.

I guess I was more of the understanding that setting up for either NAB or IEC EQ was mainly intended for the 'entire machines' overall 'sound' - and not so much for individual instruments, that's all.

But then again, I may be 'wrong' about this - and I'm still in my 'learning stage' here, so maybe I interpreted what you were trying to say incorrectly?

- But I'm certainly not trying to question anyone's veracity of what they know and are educated on by any means - at least not at my level of 'analog' knowledge so far