Thanks for you patience and for walking me through this.
Sure thing. Hopefully it’s helpful to you and others down the road.
The tech did a full set up. He actually put on new record and playback heads and calibrated and adjusted everything. I'm using the same scotch 207 tape that he used. So the machine is in top shape.
Okay. Fair enough.
I know the machine is set up to spec as the tech I worked with has extensive experience with these machines and is pretty meticulous. But maybe what is called for is just different than what I want from the machine. Maybe a slight emphasis on the high frequencies per tascam?
There’s no reason you can’t do that. A machine doesn’t HAVE to be setup to factory spec. As you get more advanced in knowing and using your machine you’ll find that’s one of the hidden beauties of using tape…between tape types/formulations, fluxivity standards, standard operating levels, bias settings and response curve tweaks there is a lot you can do with a tape machine. But it starts with understanding what all of those different facets and settings do, and once you have a grip on those things and get used to your flow and result you might go “I want more ____” and tweak your setup to lean toward that result. So there’s no reason you can’t nudge the HF record EQ, but, again, what you DON’T want to do is do it blindly. You need to establish a quantitative basis for where the machine is at and make incremental adjustments. Fortunately for you, you have a three-head machine, so you can monitor off the reproduce head in real-time as you make adjustments and listen.
I'm wondering if there is a slight bump in the high frequencies, then maybe the lower frequencies would sound less pronounced.
That’s the opposite of what I was suggesting. I was suggesting diminished HF response might bring the perception of a coincident diminished LF response because often there are HF elements to LF content, and without the HF elements prominent in the mix the LF content falls back in the mix.
The reason I thought it might have been under biased is because I had read another thread where there was a low frequency bump on the same machine and it was put out there that it was over biased, so I was just working in the other direction.
Well I don’t know who said what, but every tape machine has a LF “head-bump”…you can do a web-search on it to get the background of why it exists, but it’s part of why many people like tape, because there’s a natural LF boost, and some tape machines have it in a good spot for particular music. It’s not something you tune. It’s a fixed element related to the head design, tape speed, etc. And, again, bias level impacts distortion and HF response…LF response is not a factor relative to bias level. Period.
I'm mixing down from a tascam 388. I've thought about just bumping the low frequencies of my mix but I kind of have everything keyed in. I'm not sure I'm confident enough to make little tweaks to compensate for what I get when I monitor from the 388 to where they would translate to an even mix on the 22.
But…that…is the whole thing about mixing…that’s mixing…make yourself some cue sheets so you can document your baseline mixer settings (to be able to revert to them), run a mix, monitor off the reproduce head, tweak away! Hear your changes in real time off the reproduce head. Play. Experiment. Forget confidence. If you document your base mixer settings you can always go back to them like an undo button. And by monitoring off the reproduce head you don’t have to run a mix and play it back and try to fix what isn’t right…my goodness that’s the best part about mixing is experimenting. Try it out. Have fun.
But I'll take your advice and try the tone ladders. I do admit I'm not sure exactly what the process is. I'd venture to guess it's recording a series of frequency tones to the tape to check the response? Would you be able to walk me through it or possibly point me somewhere where the process is explained? I would definitely be curious to see how it's done, and as you mentioned it would give me important information about what the machine is actually doing.
Running tone ladders is just the same thing you do during the calibration step of checking the record frequency response. This assumes your tech already checked playback frequency response which you do by playing a tone ladder from a calibration tape, and verifying the playback electronics are reproducing within the range specified by the manufacturer. So actually, I’d ask your tech what their notes say about how the machine did with the playback frequency response check, verify it was within spec, and ask what tones were reproduced and what the levels were. They should be able to tell you the tones because they have the cal tape with the tones on it. And if they can’t remember specific levels per tone I would hope they’d have notes or recall generally how it did: “Yeah it was within +/- 2dB across the specified frequency range, head bump was around x Hz and it started to drop off at around x kHz”…something like that. But with that you know what you might expect by recording your own tone set to the tape you’re using and checking the response curve. You can just use the same tones your tech used. Take a blank reel of tape, inject each tone into the inputs, and while monitoring the tone generator signal at the input before recording, set the record level to 0VU. Then record maybe 10 seconds of each tone. At the end of the process you’ll have a “ladder” of tones recorded to tape. Now rewind to the beginning and reproduce the tone set and document the level of each tone represented on the meters. Do this for both the sync head and reproduce head. Feel free to share the results here. Does that make sense? And the quality of the tone is not critical, so you don’t need a low-distortion oscillator or anything. For this kind of thing I use an app called Tone Generator on my mobile device. Cheap, does varieties of noise as well as tone, different waveforms, nice interface for output level and frequency.
Please feel welcome to ask any clarifying questions.
One last question. You mention here the +/- range. This is in reference to the frequency adjustment? But if you're only option is a single eq, would you just test different a few different frequencies and try to get them both within range? The manual mentions 400 hz and anything over 15 kHz.
Hopefully it makes more sense after my last paragraph. It’s related to the tone ladders. Basically, on the playback side (from a cal tape, where the tones on the tape are at a precisely known fluxivity level), and on the record side (where you reproduce tones you recorded onto your tape), the manufacturer says the deck should be able to reproduce each tone within a +/- dB range of zero. In other words from x Hz at the low range to x kHz at the high range it should be able to reproduce from a cal tape or from tones recorded on your own tape no higher or lower a level than what went in (or is precisely at a known same level on a cal tape) than what is specified. Let’s see what the 20 series manual says…
Okay it says at 15ips:
40Hz - 22kHz +/-3dB @ 0VU
35Hz - 25kHz +/-3dB @ -10VU
That brings another question…you’re running your mixes at 15ips, right?
So let me know what questions you have, but you should be able to record tones at 0 or -10VU across the ranges specified above and the results on playback should be no more or less than 3dB above or below 0 or -10VU respectively. I don’t want to get too far into the weeds but note the service manual indicates to measure playback levels using an AC voltmeter measuring at the output jack for the respective track. Why? I suspect it’s because it’s more accurate. The ballistics on the Teac meters aren’t great at high frequencies. Like they can be as much as a dB off above 10kHz. But if you want to test things quick and dirty you can just use the meters, it will give you a relative sense of where the peaks and dips are and where things roll off…just be aware at high frequencies if the meter says -2VU that might be more like -1VU. And if you have a decent AC voltmeter (one that is accurate across the audio band), then you can always use that. But use a ‘Y’ cable at the output so the output is loaded (one part of the Y connected to equipment, the other being used for your meter measurement).