Tone Test for Tape Master

[soupking]

Hi GS,

When submitting a stereo track 1/2" tape to a mastering engineer, what tone frequencies need to be run at the beginning of the tape for calibration?

[loujudson]

I don't understand how one can not know this. Can you align the deck properly?

100, 1k, 10k all at zero reference level. 400Hz or 1k.

But then I grew up using analog tape...

L

[soupking]

Originally Posted by loujudson

I don't understand how one can not know this. Can you align the deck properly?

100, 1k, 10k all at zero reference level. 400Hz or 1k.

But then I grew up using analog tape...

L

I'm still learning. I've been learning to tune my piano. Next will be tape calibration. My friend who's a tech helped me the first time. I hope to get that down next.

Thanks Lou,
-soup

[loujudson]

Okay... Different worlds, really. I'm a recording and live sound engineer, and when the piano needs tuning I call a piano tuner. But then, I can't play it! I work for musicians who can't record...

L

[ARude]

Originally Posted by loujudson

I don't understand how one can not know this. Can you align the deck properly?

100, 1k, 10k all at zero reference level. 400Hz or 1k.

But then I grew up using analog tape...

L

All those tones need to be 30 seconds each. That's the abbreviated list but it's acceptable...

[soupking]

Originally Posted by loujudson

Okay... Different worlds, really. I'm a recording and live sound engineer, and when the piano needs tuning I call a piano tuner. But then, I can't play it! I work for musicians who can't record...

L

Heh, that's funny.
Me, I'm sadistic. I decided to build and operate a studio to play in.

I don't blame you. Piano tuning has about the same learning curve as basic soldering. You have to get used to sucking at it and then things start to make sense and you develop a flow.

[djwaudio]

The first thing about tones is to have a reliable tone generator. I use the Soundcheck CD by Alan Parsons. It's thorough and accurate.

I like to get 50 Hz as well as the above listed frequencies of 100, 1k, & 10k, running at 30 seconds each. 100 Hz alone tells me very little about the bass region. Together I feel much more confident. The really cool engineers add a sweep tone from 20Hz to 20kHz. Then the ME will really know where your record alignment is.

To give you an idea of how an ME deals with an incoming tape; I check the tape's documentation for information about operating levels, noise reduction systems possibly used, country of origin (for 1/4" tapes if the EQ standard isn't specified), and what machine the tape was recorded on, etc.

Next, I playback the 1k to check L&R levels and overall ballpark azimuth. Next is the 10k tone, where I'll fine tune the replay azimuth. If it's out by much I'll check the 1k L&R levels again, then back to 10k for HF EQ adjustments if needed.

Finally I'll check the 100 Hz level. Depending on the heads used on the record deck, they could be up a little or down a little. Without 50 Hz tones, I'm careful about not making any LF repro tweaks until I listen to the music. If the low-end needs adjusting, I'll do it while listening to a track or two.

Since I use a Sony APR 5000, I can store the setup in memory for recalls, or write down the values, which is very handy. It can also get me back to my in-house (MRL) calibration at the push of a button if things get weird.

Good luck, and keep the analog flame alive! I always enjoy working from tape.

[Cellotron]

Here's my requests from my website:

Please include test tones at 0dBVU at the head of the tape of at least 30 seconds of 100Hz, 1kHz, and 10kHz at the minimum. We also prefer to receive tones at 16kHz - and extra kudos if you also include 50Hz, 500Hz and 5kHz tones.

Please send tapes tails out, with leader at the heads and tail, and if possible with leader seperating each track, and leader separating the tones from the tracks.

We prefer to receive tapes without any noise reduction. If you do use noise reduction please make sure you specify which type on your track sheet and include calibration tones at the head of your reel.

Please make sure that you include a track sheet indicating tape speed, what eq curve was used (i.e. NAB, IEC, AES), what tones are recorded, if any noise reduction has been used and if so what type, titles and order of tracks and their start and length times.


I like the 16kHz tone for an extra test of the azimuth - and I like the additional other tones as double checks to make sure that there aren't any marked bumps in the tapes response that I should be aware of.

Slightly off topic of the thread - an interesting site showing measurements of the frequency responses of many commonly used analog tape recorders can be seen at Response Curves of Analog Recorders
You'll see that a lot of times 100Hz, 1kHz, & 10kHz can all be calibrated to reproduce at 0dBVU - but that the other frequencies will have some variation from flat.

Best regards,
Steve Berson

[soupking]

Cool, thanks for the info guys!

[BouncyJones]

Ι'm gonna fire this question here since this thread inspired the thought and the OP feels happy with the answers and so there's little risk of stealing the thread.

Do any masterers here have perfect pitch, and more importantly synesthesia? That is the mixture of different senses. For example, the composer Scriabin had it and it affected his compositions because he "saw" certain colours while hearing certain tones and in certain keys.

I ask all this because the idea of recording to tape captures this idea of capturing a tone, but clearly the graphs on the link above show that tapes are not completely frequency accurate.

Has anyone found themselves, within that subset of seeing colours with sound, of confusing the colour with the original key with that in which it's actually playing back within the tapes slight discrepancies?

[MarkRB]

Soup, you have to be the coolest poster on these boards for sure.

Check out this site: MRL Calibration Tapes
It will tell you all you need to know, and some. It's hard going at first but really worth the 3 or 4 re-reads.

If you are operating a tape machine seriously you need an MRL alignment tape and an oscillator (something to make tone with).

PM me if you have any questions, I'd be happy to help.

[MarkRB]

Originally Posted by BouncyJones

I ask all this because the idea of recording to tape captures this idea of capturing a tone, but clearly the graphs on the link above show that tapes are not completely frequency accurate.

Accuracy is not something tape does very well at all.

The sound of tape is hard to explain. Analogue vs Digital is like trying to describe an ocean with lego.
44,100 bits of lego can only go so far.

[finetuner]

Originally Posted by MarkRB

... Analogue vs Digital is like trying to describe an ocean with lego.
44,100 bits of lego can only go so far.

[Thomas W. Bethe]

Originally Posted by loujudson

I don't understand how one can not know this. Can you align the deck properly?

100, 1k, 10k all at zero reference level. 400Hz or 1k.

But then I grew up using analog tape...

L

The tone "Level" on the tape depends on the tape speed. 15 or 30 ips 0 dBU, 7.5 ips should be -10 dBU and what ever you decide to put on the tape LABEL the tape box with what the tones are, in what order, at what level and where on the tape they are located. You should also write on the box at what reference flux your recording was made at and anything else that would help the mastering engineer.

[Paul Gold]

Originally Posted by Thomas W. Bethe

The "Level" on the tape depends on the tape speed. 15 or 30 ips 0 dBU, 7.5 ips should be -10 dBU

Why 7.5ips at -10dBu? There were plenty of professional recordings done at 7.5ips as dubs or long format broadcast or for many other reasons. And I think you mean -10dBv.

[soupking]

Originally Posted by MarkRB

Soup, you have to be the coolest poster on these boards for sure.

Check out this site: MRL Calibration Tapes
It will tell you all you need to know, and some. It's hard going at first but really worth the 3 or 4 re-reads.

If you are operating a tape machine seriously you need an MRL alignment tape and an oscillator (something to make tone with).

PM me if you have any questions, I'd be happy to help.

Thanks Mark, I don't realize it sometimes but you guys mean the world to me. Between my tech friend Chaz and GS I've gotten a college education in recording to tape and have made a proper investment thanks to everyone's feedback. That and I've picked up a bunch of techniques and had a lot of stupid questions asked.

I now know how not only how to make wires, but normalize patchbays, gain staging/distortion control, AUX routing, signal problem solving, I'm learning to tune my piano, and next I'll be sourcing blown tubes since half my gear is Ampex or Pultec.

I have a test tape and a han-d-mag. I haven't tested the azimuth of the machines yet. The levels are so damn low on the inputs that I'm wondering if it needs another re-calibration (Whole other thread).

But I also have a JH-110 and second TASCAM 48 that needs fixing.

IT NEVER ENDS!!!

Now I just need to learn how to budget.

Peace,
-soup

[soupking]

Originally Posted by Thomas W. Bethe

The "Level" on the tape depends on the tape speed. 15 or 30 ips 0 dBU, 7.5 ips should be -10 dBU and what ever you decide to put on the tape LABEL the tape box with what the tones are, in what order, at what level and where on the tape they are located. You should also write on the box at what reference flux your recording was made at and anything else that would help the mastering engineer.

Thomas, you may have answered a serious problem for me.

I'm recording to a 1/2" TASCAM 48, which to my knowledge has a fixed and varispeed setting. I don't have the manual in front of me, but we've been trying to hit the tape as hard as possible, the mixer behind it's getting easily over 0-db, but the needles are like mules, they just won't go up.

Am I missing something? My friend and I have been bending over backwards to get a solid signal to tape. It feels like it shouldn't be this hard.

Any input, like always, is awesome.

[lucey]

-10 tape machine

-4 console

???

You need to get a handle on your levels with an AC voltmeter and MRL.

[soupking]

Originally Posted by lucey

-10 tape machine

-4 console

???

You need to get a handle on your levels with an AC voltmeter and MRL.

Hi Brian,

That's interesting. We used my tech friend's tone generator. I'll ask him about the -10db and AC voltmeter.
Aslo if whatever Thomas said above holds any bearing on my machine I'll have to find the ips on a TASCAM 48.

Thanks!
-m

[jamsmith]

Originally Posted by lucey

-10 tape machine

-4 console

???

You need to get a handle on your levels with an AC voltmeter and MRL.

I think you mean +4 console(?)

Originally Posted by soupking

Am I missing something? My friend and I have been bending over backwards to get a solid signal to tape. It feels like it shouldn't be this hard.

Other factors. What are you sending to tape? Submix? Does your console have tape-out jacks or are you high-jacking the FX loop? Do you have proper gain at the input? And since this thread is about tone tests, do have an alignment tape. Tascams need pretty regular adjustment. If you have noise reduction unit, the gains may need adjustment on the cards.

I have to ask though: why? A half-inch 15ips machine (yes, that is the 48s speed) doesn't give you that sound like like a 2" 30ips machine, that tape is outrageously price, with NR its noisy, no autolocate, constant need of maintenance. My happiest day (10 years ago) was when we canned the Tascam 38 and loaded in 2 ADATs w/BRC.

Originally Posted by BouncyJones

Do any masterers here have perfect pitch...?

That reminded me of question I was going to ask. I think of perfect pitch as know exactly what note is being played. I have "perfect tuning" in that I can tune my guitar always be within a couple of cents of perfect. But sometime I end up in Eb, or a couples of time in F instead of E (in all fairness to myself on the Eb and E, I do keep guitar in both tunings all the time.) So what would "perfect RELATIVE pitch be called?

[soupking]

Originally Posted by jamsmith

I think you mean +4 console(?)



Other factors. What are you sending to tape? Submix? Does your console have tape-out jacks or are you high-jacking the FX loop? Do you have proper gain at the input? And since this thread is about tone tests, do have an alignment tape. Tascams need pretty regular adjustment. If you have noise reduction unit, the gains may need adjustment on the cards.

I have to ask though: why? A half-inch 15ips machine (yes, that is the 48s speed) doesn't give you that sound like like a 2" 30ips machine, that tape is outrageously price, with NR its noisy, no autolocate, constant need of maintenance. My happiest day (10 years ago) was when we canned the Tascam 38 and loaded in 2 ADATs w/BRC.

Well, I'm going direct to tape from the preamp. The mixer is used to monitor the signal after tape. The 1/2" TASCAM 48 I'm using doesn't get noisy (if I can hit the tape hard enough) with no NR, and it has RTZ and SET to mark a spot. It also has balanced inputs (+4 db) which the 38 does not have and which is part of the reason I need so much gain. Prior to my two 48's, I got a 38. The 38 is on the work bench awaiting a pinch roller so I can sell it.

[MAzevedo]

Originally Posted by jamsmith

I have to ask though: why? A half-inch 15ips machine (yes, that is the 48s speed) doesn't give you that sound like like a 2" 30ips machine, that tape is outrageously price, with NR its noisy, no autolocate, constant need of maintenance. My happiest day (10 years ago) was when we canned the Tascam 38 and loaded in 2 ADATs w/BRC.

I like 15ips for tracking, moves the head bump down and gets some great low end happening. With modern tape formulations, you can hit it hard enough that the noise isn't a big issue. Now, I am not going to say I'd rather have a 1/2" deck than a 2", but to me 'that sound' is 15ips. If you'd rather listen to audio through ADAT converters, that's all you.

[Bob Olhsson]

If we had modern tape in 1975, nobody would have probably gone 30 or half inch.

[glassmaster]

Originally Posted by Bob Olhsson

If we had modern tape in 1875, nobody would have probably gone 30 or half inch.

Wow. Imagine that - John Philip Sousa's greatest hits on 15ips tape performed by the March King himself.

But Bob, you're dating yourself…

[Thomas W. Bethe]

Originally Posted by Paul Gold

Why 7.5ips at -10dBu? There were plenty of professional recordings done at 7.5ips as dubs or long format broadcast or for many other reasons. And I think you mean -10dBv.

Paul,

Tones need to be done at - 10 dBU (U not V) at 7.5 ips. You can record music at what ever level you want to at 7.5 ips depending on the effect and saturation you are looking for. dBV is the reference level stated for Tascam or prosumer decks dBU is for stands for dB UNIVERSAL where you do not specify the impedance but the signal is a .775 VAC and is most often the newer way of stating levels.
More info here Line level - Wikipedia, the free encyclopedia or Commonly used Voltage and Audio Levels

soupking,


Neat calculator here dB dBu dBV dBm to volts conversion calculator volt - volts to dBu and dBV dB - convert dB volt calculation online attenuation loss gain ratio reference - sengpielaudio in case you need one. You might also want to read the white papers at MRL Calibration Tapes

[Thomas W. Bethe]

Originally Posted by soupking

Thomas, you may have answered a serious problem for me.

I'm recording to a 1/2" TASCAM 48, which to my knowledge has a fixed and varispeed setting. I don't have the manual in front of me, but we've been trying to hit the tape as hard as possible, the mixer behind it's getting easily over 0-db, but the needles are like mules, they just won't go up.

Am I missing something? My friend and I have been bending over backwards to get a solid signal to tape. It feels like it shouldn't be this hard.

Any input, like always, is awesome.

I had the Tascam 58 ( 8 channels on 1/2" tape) which is the bigger brother of the 48. I no longer have the machine but if memory serves it was all - 10 dBV in and out. If your console outs are +4 dBU you will need to insert a resistive pad into the lines that feed the deck. Tape decks are biased for a certain tape and if you are using a tape that the machine was not biased for you may be getting the results you are describing. The deck can be re-biased for the tape you are using but you will have to have a 1/2" MRL tape to check the reproduce alignment before you can do a record alignment and bias setup. There maybe someone in your area that can do this for you for a reasonable price if you don't have the gear or the knowledge to do it yourself. Do you have the original manual that came with the 48?


Best of luck!

[soupking]

Originally Posted by Thomas W. Bethe

I had the Tascam 58 ( 8 channels on 1/2" tape) which is the bigger brother of the 48. I no longer have the machine but if memory serves it was all - 10 dBV in and out. If your console outs are +4 dBU you will need to insert a resistive pad into the lines that feed the deck. Tape decks are biased for a certain tape and if you are using a tape that the machine was not biased for you may be getting the results you are describing. The deck can be re-biased for the tape you are using but you will have to have a 1/2" MRL tape to check the reproduce alignment before you can do a record alignment and bias setup. There maybe someone in your area that can do this for you for a reasonable price if you don't have the gear or the knowledge to do it yourself. Do you have the original manual that came with the 48?


Best of luck!

A friend helped me with this before. He's a pro, but he's under the weather right now, so I'm fending for myself while were tracking today.

Yeah, I was just looking at it and it says to calibrate to -10 db, but I think it's referring to the unbalanced connectors right? If I'm using the balanced I'd think I'd still calibrate to +4 db right?

Additionally, the 2/3 hot pin is backwards or something or at least that's what the guy warned me about. I don't know if that would affect it or not.

The High EQ was kind of strange too. It didn't seem to really do anything after the biasing. Thought it's been a while. i can't remember if we did that portion first or not. I do remember that part kind of boggled us, but I'm not really sure if that relevant to this issue.

At least I'm more interested in investigating other possible issues like proper input cal and pin outs etc.

[Paul Gold]

Originally Posted by Thomas W. Bethe

Tones need to be done at - 10 dBU (U not V) at 7.5 ips.

I have never seen nor heard of this. I must have missed this standard. Have I been living in a cave? What is the purpose of having calibration tones at a level other than at "0"? VU meters are not accurate at -10 on the scale. Is there something on the MRL site or AES or NAB that explains this?

Edit: At standard line level of +4dBu = 0VU you would be calibrating to -14VU

[jamsmith]

Originally Posted by Paul Gold

I have never seen nor heard of this. I must have missed this standard. Have I been living in a cave? What is the purpose of having calibration tones at a level other than at "0"? VU meters are not accurate at -10 on the scale. Is there something on the MRL site or AES or NAB that explains this?

Edit: At standard line level of +4dBu = 0VU you would be calibrating to -14VU

I think wired are getting cross here. Some are talking about the internal levels, ie, what on the VU meters vs the external levels, ie, the voltage level on the input and output.

I won't swear to it, but I think the 48 is a professional level machine with balanced +4dBu inputs. The 38, with phono plugs was -10.

I would worry if the pins are "backwards", unless you are running something in parallel. Phase is relative. If they are all "backward", its all the same in then end.

[ITJ]

Originally Posted by loujudson

I don't understand how one can not know this. Can you align the deck properly?

100, 1k, 10k all at zero reference level.

At least 100, 1k, and 10k. Andrew Berliner used 700Hz in place of 1k.


I do 50, 100, 1k, 10k, and 16k.