record eq

  • Thread starter Thread starter FALKEN
  • Start date Start date
FALKEN

FALKEN

*************************
as per my fostex e-22, which I have been mixing down to. I love it to death. I also love having several 1/2" formats and being able to swap tapes. I think I just love 1/2" tape. That being said I am also a perfectionist and there is a small issue driving me nuts. I know I always come here with these "small issues" and what more can a few guys on the net do. but honestly you all are very helpful and always seem to point me in the right direction. And I am always thankful.

My problem is that the record eq doesn't do anything. Which in itself makes no sense to me, because the playback eq works fine. And it is the same story on both channels; playback eq is fine; record eq does nothing.

While recording various frequencies and monitoring playback you can see that the channels are off from each other, but only by say a couple decibels. Since everything sounds ok, I've been working with it.

However, it is coming time again to be sending out demos, and I want everything to be perfect. So I've been working on some mixdowns, and what is happening is that one channel, compared to the other, has a louder RMS, but quieter peaks. by a couple decibels. It is driving me crazy. The drums shift to one side (because they represent the peaks) and if I boost the other to make them centered then the material on that side is too loud. I thought about it a long time and I think the peaks are hotter on one side because it has more high frequency and the RMS is louder on the other side because it has more low frequency. This seems to make intuitive sense, also. I did this test with a mono mix, just to avoid any differences a stereo mix might cause.

So, I guess I have three options. I could go to a studio, but honestly, with the current setup I'm running, and the years I have invested doing this, I think my recordings sound way better than any local studio. I could try to fix it, but I wouldn't know where to start. How could it be that the caps went bad, but only on the record eq, and on both channels on top of it. It doens't make any sense. A third option would be to adjust the playback eq to even things out. This would get things very close but my tapes wouldn't play back properly on any other machine.

So, I turn to you wise ones for advice. Did I overlook something? What would you do? Thanks in advance.
 
minimum adjustment range

I don't know anything about Fostex.... But on my Tascam I chased record EQ around for a while till I realized that there was a very limited adjustment range. On the order of 1 dB. Doing a lot of reading and measurements I figure that the record side is pretty much fixed in hardware. The adjustment is for the last tweek. YMMV

--Ethan
 
Falken,
Not familiar with the machine but if you are getting compressed peaks but acceptable lower levels it sounds like those peaks are saturating the tape.

It sounds as if the machine needs a service/ alignment.

Rec eq is almost the last adjustment after all others are done, and it's not designed to compensate for significantly worn heads or misaligned heads or machine not aligned to the tape.
It's more to make slight compensations at the high freq end as EVM said though I would normally expect a range greater than 1 db.

If you're hearing a big difference between channels it's unlikely rec eq alone would bring it back under any circumstances.

Cheers, Tim
 
I had the same problem with my two teac machines (you may remember) at i worked out that my recording levels were too hot. After sorting them out all was well.

Your heads may be worn aswell so you may wanna check em out
 
Uh.. this would be one reason why I have lots of extra audio cards for my recorders. The M-79 does everything on one card, and I have 6 extras. The older 3M machines used the same card format, but it takes at least 4 cards to make a whole channel: bias, line amp, playback eq and rec eq. I try to keep several known good cards around so I can swap one in case there is a problem, do a simple realignment, then fix the problem card later (off line when I have time to spare). Is that an option for you?

Otto
 
ofajen said:
I try to keep several known good cards around so I can swap one in case there is a problem, do a simple realignment, then fix the problem card later (off line when I have time to spare). Is that an option for you?
Click to expand...
Given that the E-22 is fantastically rare, I rather doubt it. It probably has the same cards as the E-2 though, possibly even the Model 20 or R8 so it might be possible to acquire spares that way.
 
FALKEN said:
as per my fostex e-22, which I have been mixing down to. I love it to death. I also love having several 1/2" formats and being able to swap tapes. I think I just love 1/2" tape. That being said I am also a perfectionist and there is a small issue driving me nuts. I know I always come here with these "small issues" and what more can a few guys on the net do. but honestly you all are very helpful and always seem to point me in the right direction. And I am always thankful.

My problem is that the record eq doesn't do anything. Which in itself makes no sense to me, because the playback eq works fine. And it is the same story on both channels; playback eq is fine; record eq does nothing.

While recording various frequencies and monitoring playback you can see that the channels are off from each other, but only by say a couple decibels. Since everything sounds ok, I've been working with it.

However, it is coming time again to be sending out demos, and I want everything to be perfect. So I've been working on some mixdowns, and what is happening is that one channel, compared to the other, has a louder RMS, but quieter peaks. by a couple decibels. It is driving me crazy. The drums shift to one side (because they represent the peaks) and if I boost the other to make them centered then the material on that side is too loud. I thought about it a long time and I think the peaks are hotter on one side because it has more high frequency and the RMS is louder on the other side because it has more low frequency. This seems to make intuitive sense, also. I did this test with a mono mix, just to avoid any differences a stereo mix might cause.

So, I guess I have three options. I could go to a studio, but honestly, with the current setup I'm running, and the years I have invested doing this, I think my recordings sound way better than any local studio. I could try to fix it, but I wouldn't know where to start. How could it be that the caps went bad, but only on the record eq, and on both channels on top of it. It doens't make any sense. A third option would be to adjust the playback eq to even things out. This would get things very close but my tapes wouldn't play back properly on any other machine.

So, I turn to you wise ones for advice. Did I overlook something? What would you do? Thanks in advance.
Click to expand...

Are these multi-turn trimpots we are talking about?

If they are, you could be looking at 20 full turns end to end. i have also seen them just plain broken inside from years of turning abuse. If your playback is stable (no drop-outs and plays the same every time) then you are probably looking at an electronic problem with one of your channels. If your heads were worn, you would have the problem come and go. Check your tape alignment (look at the heads when the tape is running. The tape should be dead in the center of the track width and running straight, not sliding up and down). I would do a full transport alignment first along with checking tape tension. Look at your heads. They should have wear marks in the center of the head and the marks should not look like an hourglass, or a "V" or an upside down "V". The tape should not have any funny edge damage. If you see any edge damage (looks like the center is flat and the top and bottom edges are wrinkled) you can bet you need a mechanical transport alignment.

One last thing, find some scrap tape. Load the machine (power Off), taks a black marker and color the heads in the center black.

Power the machine and run the tape.

Remove the tape and look for the tape wear marks. They should be straight up and down about the center of each head. Clean the machine.

Wear marks look like this:

| Center |

Not like this:
/ Center \

Or this"
\ Center /

Or the "hourglass" shape.

Good Luck.
 
first off, thank you all for taking the time to help me out!!! I've made some progress but not much. I did get the pots to do something, running at 30 ips. But the adjustment range was very small as indicated. Too small to calibrate properly. For some reason, I am within 1 db at 20khz, but at 15khz, the right channel is at +3 and the left is at -1, on repro, with inputs set to 0. this is after running the MRL for playback calibration of level and eq. So it must be something else. The tape does not move vertically at all on playback. I don't see how it could be a tension problem because wouldn't it affect both channels equally? The heads are worn but they still sound good and this problem is not intermittent. so I dont think that's the cause. I called fostex and they dont have spare cards. I will experiment more.
 
whoa. ok, it seems as though I was on the wrong side of my bias cap. (see the older thread I bumped). I re-biased to a 2 db drop and the frequency response is now relatively even between channels. It is flat at 1khz and 20khz, exactly 1 db down at 15 khz, and between .5 and 1 db up at 400 hz depending on the channel. Is this good?
 
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