Metering Problem

Bguzaldo

New member
I've got a Tascam MSR 24 and lately I've noticed particularly when recording bassier instruments the level will appear to be higher after I record it...

So say I record a Bass Drum and while I'm recording I appear to be hitting a healthy 0dB mark. When I play back the meters will read upwards of +6 to +12 dB.

Now I have had success recording at -6dB and then ending up around 0, but I'm just wondering why this is and if its typical or not

Thanks,
-Barrett
 
At long last, someone else!

I've got a Tascam MSR 24 and lately I've noticed particularly when recording bassier instruments the level will appear to be higher after I record it...

So say I record a Bass Drum and while I'm recording I appear to be hitting a healthy 0dB mark. When I play back the meters will read upwards of +6 to +12 dB.

Now I have had success recording at -6dB and then ending up around 0, but I'm just wondering why this is and if its typical or not

Thanks,
-Barrett

Finally someone who noticed! I have had a TSR-8 and an MSR-24 for 16 years. I noticed this phenomenon way back then. Of course nobody at Tascam new what I was talking about. It is normal. I have already posted about this here about 6 months ago. I only got 1 response by someone who said they think they have seen this. I have had thought experiments to why this happens. The symptoms you describe are exactly how I would describe it. I have found it is just Kick drum and bass guitar that does it when there is a very dynamic signal. Kick is always dynamic. Bass isnt. If the signal is sustained it comes back correct, That is what a test tape or tone would do. It is the inrush of a rising signal that makes this happen. It is because of what is called Inductive Reactance. It is the resistance of current through a coil that is increased with frequency. The tape heads are coils. So is a guitar pickup, High output guitar pickups lose treble. So the kick and bass inrush of signal on the punchy dynamic signals are seen by the head coils as a very low frequency, almost 1hz, it therefore allows a lot of current to rush in on all the initial attacks of the signal. I simply do what you have been doing and anticipate this and adjust. I recently had an MSR-16 here that I was calibrating. I found an interesting correlation. The MSR-16 had the most boost in signal, the TSR-8 had the least. The MSR-24 was in the middle. Apparently this effect is a function of track width. The MSR-16 is the thinnest and the TSR-8 is the thickest. I dont know if the fact these are 2 head machines that causes the effect. I just bought an MS-16 with 3 heads. I will check to see if it has this effect also.
VP
 
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I've got a Tascam MSR 24 and lately I've noticed particularly when recording bassier instruments the level will appear to be higher after I record it...

So say I record a Bass Drum and while I'm recording I appear to be hitting a healthy 0dB mark. When I play back the meters will read upwards of +6 to +12 dB.

Now I have had success recording at -6dB and then ending up around 0, but I'm just wondering why this is and if its typical or not

Thanks,
-Barrett

As I recall, the metering is being influenced by the dbx NR either on input, output, or both. You'd need a block diagram to determine the exact path.
 
I've got a Tascam MSR 24 and lately I've noticed particularly when recording bassier instruments the level will appear to be higher after I record it...

So say I record a Bass Drum and while I'm recording I appear to be hitting a healthy 0dB mark. When I play back the meters will read upwards of +6 to +12 dB.

Now I have had success recording at -6dB and then ending up around 0, but I'm just wondering why this is and if its typical or not

Thanks,
-Barrett

I'm not a user of this machine, so take all of this for what it's worth:

Obviously, the total system response is not right on the low end.

The most likely causes would seem to be:

1) LF playback control/compensation is cranked too high. Did you calibrate the machine? Maybe it was set during playback only for flat response. It's better to set it during record calibration, so you can balance the overall response to keep the low end bump under control. If it uses NAB eq, it is probably more capable of excessive low end emphasis.

2) As noted, there may be an issue with improper setting of NR or the NR may be enhancing the amount of the error.

Cheers,

Otto
 
I'm not a user of this machine, so take all of this for what it's worth:

Obviously, the total system response is not right on the low end.

The most likely causes would seem to be:

1) LF playback control/compensation is cranked too high. Did you calibrate the machine? Maybe it was set during playback only for flat response. It's better to set it during record calibration, so you can balance the overall response to keep the low end bump under control. If it uses NAB eq, it is probably more capable of excessive low end emphasis.

2) As noted, there may be an issue with improper setting of NR or the NR may be enhancing the amount of the error.

Cheers,

Otto

The only way to test if item 1 above is correct would beto record tones with the dbx off. Even then, you would need to use a calibrated outboard meter because Tascam's machine meters are frequency weighted and only reliable around 1Khz.

Statement 2 is incorrect because of the way dbx works, the metered level is going to be different from input to output.
 
Statement 2 is incorrect because of the way dbx works, the metered level is going to be different from input to output.

I normally avoid NR like the plague, but I do recall that dBx is a full-range 2:1 compression/expansion system, so if the record side electronics is accurate, but the playback response is high by 3 dB at 50 Hz, as it might well be due to the normal 15 ips head bump, for instance, then you could see the dBx playback circuit giving you a +6 dB output on playback even though you monitored 0 dB at the time of recording.

Cheers,

Otto
 
I'm not a user of this machine, so take all of this for what it's worth:

Obviously, the total system response is not right on the low end.

The most likely causes would seem to be:

1) LF playback control/compensation is cranked too high. Did you calibrate the machine? Maybe it was set during playback only for flat response. It's better to set it during record calibration, so you can balance the overall response to keep the low end bump under control. If it uses NAB eq, it is probably more capable of excessive low end emphasis.

2) As noted, there may be an issue with improper setting of NR or the NR may be enhancing the amount of the error

Cheers,

Otto

Can you please read post #2?
VP
 
The only way to test if item 1 above is correct would beto record tones with the dbx off. Even then, you would need to use a calibrated outboard meter because Tascam's machine meters are frequency weighted and only reliable around 1Khz.

Statement 2 is incorrect because of the way dbx works, the metered level is going to be different from input to output.

All my machines are properly calibrated. can you please read post #2.
VP
 
All my machines are properly calibrated. can you please read post #2.
VP

My only point is that noise reduction can make metering a big question mark. If input metering is before the encode, you have no idea what level the tape is actually being hit with. If it post encode, you are looking at the compressed signal and not what the machine's input electronics are seeing. If metering is pre decode on playback, you'll see how the machine recorded the compressed signal. If post-decode, the meters show the expanded signal. Add to that the fact that TASCAM would frequency weight the meters on their analog machines and you are really flying blind.

All of this is much to do about nothing if you are getting good sounding recordings. Once a system us calibrated, a machine's meters are about the least important things to worry about.
 
My only point is that noise reduction can make metering a big question mark. If input metering is before the encode, you have no idea what level the tape is actually being hit with. If it post encode, you are looking at the compressed signal and not what the machine's input electronics are seeing. If metering is pre decode on playback, you'll see how the machine recorded the compressed signal. If post-decode, the meters show the expanded signal. Add to that the fact that TASCAM would frequency weight the meters on their analog machines and you are really flying blind.

All of this is much to do about nothing if you are getting good sounding recordings. Once a system us calibrated, a machine's meters are about the least important things to worry about.

That all makes sense, but what we are experiencing is an obvious phenomenum that is in all of my machines except I havent tried my MS-16 yet. In my post I explained my theory about why I think it is happening.
VP
 
Can you please read post #2?
VP

Already read it. True enough, the head bumps seem to be worst on the narrowest track machine. The overall system response is gonna tail off on the low end, rise to a peak somewhere in the 60-80 Hz region, then dip down somewhere in the 100 to 140 Hz region. To keep the dip reasonable, you'll probably have to have that bump go several dB above 0. So your overall response down in the area of that bump will be a few dB high and then dBx doubles that effect. Add on the fact that you may be using LED segment meters which have more of a peaking characteristic and not an SVI response and it's no wonder you may see different metered response between sustained bass notes and bass drum peaks. Factory spec will be based on steady tones, not drum beats.

Cheers,

Otto
 
Thanks guys. I see I've got a lot of good info to sort through. I'm glad to hear that this problem is common and not just me being an idiot. I really appreciate all the help.

-Barrett
 
Already read it. True enough, the head bumps seem to be worst on the narrowest track machine. The overall system response is gonna tail off on the low end, rise to a peak somewhere in the 60-80 Hz region, then dip down somewhere in the 100 to 140 Hz region. To keep the dip reasonable, you'll probably have to have that bump go several dB above 0. So your overall response down in the area of that bump will be a few dB high and then dBx doubles that effect. Add on the fact that you may be using LED segment meters which have more of a peaking characteristic and not an SVI response and it's no wonder you may see different metered response between sustained bass notes and bass drum peaks. Factory spec will be based on steady tones, not drum beats.

Cheers,

Otto

Thanks for your help, I am not sure now, but I think it does this phenomenum even without DBX. I will check to see.
VP
 
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