Topic: What is the best part of the rig to get most of the gain from ?

[Todd R]

With many of the commercially made preamps that average around 60db of total gain, when running one close to it's max gain capability, you can have increased THD in the pre, as well as overloading of the line inputs on the recorder. I also recall that the Beyer MV100 was only a 20 db gain preamp and I remember it sounded terrible cranked to the max, even though it was not too hot for the recorders.

However, if Chris Church has recommended running his very hot into the R09, he clearly designed it to do so and what you say makes total sense. The universal answer to the OP's question in the subject line for most recording setups is what Ned said.

If you are running a V2 or Sonosax cranked near the max, it would not be a good thing for most recorders I know of, definately.

Just to be more clear on all this clipping/overloading/brickwalling stuff:

There are several places where you can have overloading leading to distortion --

- at the mics (mics cannot handle the SPLs)
- at the input of the preamp (cannot take that hot of a signal from the mics)
- at the output of the preamp (cannot provide as high of a level of signal on its outputs after applying gain)
- at the input of the recorder (cannot accept that hot of a signal from the preamp)

The MV100's problem (I used to own one, and modded it to fix this problem) isn't that it cannot take a hot signal coming from the mics, it is that it cannot actually provide an output signal that is 20db above the input signal it is accepting (the third distortion type in the list above).

So it was designed to take a hot input, which it can, and it doesn't overall output too hot of a signal for the recorder as Brad notes (so none of the 4th type of distortion above) -- it just can't perform the minimum 20db gain function for all input signals that meet the max input spec.  Probably anecdotal evidence on my part, but I think this is pretty unusual -- overall just a crappy design on Beyer's part. I haven't come across this much -- generally it seems that manufacturers will insure the integrity of their design such that if the minimum gain is applied and the maximum input level is not exceeded, the preamp will not brickwall on the outputs.

Anyway, that's a long winded aside -- really just saying that the MV100 IMNSHO was a crap-ass design, and it shouldn't be used as a metric of how to set gain more generally. 

[Church-Audio]

Hello,

my current rig consists in a ST-9100 preamp and an Edirol R09-HR.
I'd like to know which one is the best to get most of the gain from.

Thank you

Get the most from the preamp  then get the rest from the R09 thats the point of the preamp. To reduce the need for gain from the R09 to get a better signal to noise ratio.

[fandelive]

If it takes a lot of gain from the HR to get the levels even to peak at -12 or so, I wouldn't raise the HR's level any further though. With 24 bit, you can add the extra gain in post without adding audible noise.

I didn't even knew that thing about 24 bit !!
This thread has been very usefull to me so far and I thank you all for that.

I'm gonna record in 24/48 (always did that way since I own the R09-HR), set the CA-9100 preamp at 90/100%, the Edirol at unity gain (38) and add the extra gain in post.

Thank you very much.

[Church-Audio]

If it takes a lot of gain from the HR to get the levels even to peak at -12 or so, I wouldn't raise the HR's level any further though. With 24 bit, you can add the extra gain in post without adding audible noise.

I didn't even knew that thing about 24 bit !!
This thread has been very usefull to me so far and I thank you all for that.

I'm gonna record in 24/48 (always did that way since I own the R09-HR), set the CA-9100 preamp at 90/100%, the Edirol at unity gain and add the extra gain in post.

Thank you very much.

Well I dont think I would do that. I would run the preamp at 90 to 100% then increase level on the recorder until you are at about
-10 or so then normalize in post. If you are sitting at -30 or so thats a whole lot of gain to make up in post. I dont think that will be the case but its better to shoot for a target then to try and boost later on. -10 Is a good place to start it leaves you lots of headroom.

Chris

[fmaderjr]

Yes, follow Chis' advice posted above and you should never have a problem.

[Todd R]

Without regard to any specific device....

You want to get max/safe gain as soon as possible in your signal chain.

Some get enough gain with no preamp -  so only 1 gain stage. (mic > line)

Some use two gain stages. Preamp > Recorder gain. You want to get the gain at the first stage...Ideally the second should be unity - or something specific for that device. (despite the term, it seems "line in" isnt a totally reliable/universal spec)

If you undergain your 1st stage and boost in a second stage...you also increase the noise from the first device by the same amount.

Generally, this seems right, though I'd like to learn a bit more about it.

For the bolded part, I think this is a little off. If you undergain the first stage and add gain at the second, you increase the noise associated with the first stage (the noise from the preamp itself) by the amount of gain you add at the second stage.  But there isn't any difference to the inherent noise of the mics (or the noise in the venue itself).  For the mic noise, I don't think it would be any different if you ultimately wanted 40db of gain whether you applied 40db at the 1st stage and 0 at the 2nd vs applying 20db at the first stage and 20db at the 2nd -- either way the mic noise is boosted by 40db.

This is where I'd like a better understanding from what runonce is saying -- if the noise of the preamp is absolutely swamped by the mic noise level and the level of noise in the venue being recorded (as in many db's below), does it make much/any difference if the total gain is applied equally across two stages vs being applied 100% at the first stage?

Say that the noise level of the preamp is -100db, and the noise level of the combined mic's inherent noise and noise in the venue is -70db, does it matter if you apply a second gain stage with say 10db of gain?  You've raised the noise level of the preamp induced noise from the first gain stage by 10db, but that noise component was already 30db less than the noise from the mics -- isn't that boosted level of noise from the preamp stage buried from the mic anyway?

[Church-Audio]

Without regard to any specific device....

You want to get max/safe gain as soon as possible in your signal chain.

Some get enough gain with no preamp -  so only 1 gain stage. (mic > line)

Some use two gain stages. Preamp > Recorder gain. You want to get the gain at the first stage...Ideally the second should be unity - or something specific for that device. (despite the term, it seems "line in" isnt a totally reliable/universal spec)

If you undergain your 1st stage and boost in a second stage...you also increase the noise from the first device by the same amount.

Generally, this seems right, though I'd like to learn a bit more about it.

For the bolded part, I think this is a little off. If you undergain the first stage and add gain at the second, you increase the noise associated with the first stage (the noise from the preamp itself) by the amount of gain you add at the second stage.  But there isn't any difference to the inherent noise of the mics (or the noise in the venue itself).  For the mic noise, I don't think it would be any different if you ultimately wanted 40db of gain whether you applied 40db at the 1st stage and 0 at the 2nd vs applying 20db at the first stage and 20db at the 2nd -- either way the mic noise is boosted by 40db.

This is where I'd like a better understanding from what runonce is saying -- if the noise of the preamp is absolutely swamped by the mic noise level and the level of noise in the venue being recorded (as in many db's below), does it make much/any difference if the total gain is applied equally across two stages vs being applied 100% at the first stage?

Say that the noise level of the preamp is -100db, and the noise level of the combined mic's inherent noise and noise in the venue is -70db, does it matter if you apply a second gain stage with say 10db of gain?  You've raised the noise level of the preamp induced noise from the first gain stage by 10db, but that noise component was already 30db less than the noise from the mics -- isn't that boosted level of noise from the preamp stage buried from the mic anyway?

Its always best to get the most gain from the preamp with the least self noise.. No matter where in the chain that preamp is. Getting gain at the first stage only really helps if you have long cable runs between your recorder and the preamp.. But in the case of the 9100 the way it was designed was to have high headroom and 22db of gain. With the noise floor being below -100db Unweighted... broad band. It makes the most amount of sense to get the gain with the 9100 first. Other preamps I cant comment on.

Chris

[aaronji]

(btw, there are universal standards for line level. Generally there are devices with unbalanced consumer line inputs at -10db sensitivity, and professional balanced line inputs at +4db sensitivity. Obviously, this 14db difference in sensitivity is significant, and something that must be considered as a place to start when getting distortion on line inputs, with recording levels that do not go over zero. Most recorders today have active electronics between the physical input and the gain control, which is why they can overload so easily with unbalanced line inputs that are -10db consumer line level.)

As I understand it, there aren't really universal standards.  Particularly with the consumer stuff, there is quite a bit of variation.  Even with the pro stuff, there are different standards (such as ARD at +6 dBu).  Also, those nominal levels are -10 dBV and +4 dBu, so they are actually ~11.78 dB apart (not 14)...

[datbrad]

(btw, there are universal standards for line level. Generally there are devices with unbalanced consumer line inputs at -10db sensitivity, and professional balanced line inputs at +4db sensitivity. Obviously, this 14db difference in sensitivity is significant, and something that must be considered as a place to start when getting distortion on line inputs, with recording levels that do not go over zero. Most recorders today have active electronics between the physical input and the gain control, which is why they can overload so easily with unbalanced line inputs that are -10db consumer line level.)

As I understand it, there aren't really universal standards.  Particularly with the consumer stuff, there is quite a bit of variation.  Even with the pro stuff, there are different standards (such as ARD at +6 dBu).  Also, those nominal levels are -10 dBV and +4 dBu, so they are actually ~11.78 dB apart (not 14)...

The 2 standards we face are for gear intended for sale and use in the USA, and the +6 level is a standard in Europe. It's just like the difference in AC power standards. Regardless, my understanding is that both dBV and DBu are measures of voltage where each unit of measure represents 1 milliwatt of gain, only difference being the impedance. Even if it is only effectively a 12db difference, that is more than double in actual "loudness". This means that a balanced XLR line is made to accept twice the signal level that an unbalanced consumer line input can, which is the main point I was making.

[it-goes-to-eleven]

With 24 bit, you can add the extra gain in post without adding audible noise.

I didn't even knew that thing about 24 bit !!

That's because it isn't true.

[fmaderjr]

With 24 bit, you can add the extra gain in post without adding audible noise.

I didn't even knew that thing about 24 bit !!

That's because it isn't true.

I suppose if the 24 bit signal is low enough, you will add noise that is audible, but not nearly as much as if the signal was 16 bit. Is that why your are saying not true, I guess I can't argue with you. I don't know the technical stuff as well as you may know it. I was just trying to give advice that should help a beginning taper make a good sounding recording with no danger of distortion and with a minimum of stress while making the recording.

I think peaking at -12 dB to -6 dB at most is good practice for a new taper (if not all tapers) when recording in 24 bit. There will be no danger of peaks distorting, they won't have to stress about constantly monitoring their levels, and their recordings will sound fine when boosted. However this a a hobby we are all in for fun, so we should all use whatever method works well for us. This method has been recommended by many here and it has worked well for me.



 

[it-goes-to-eleven]

With 24 bit, you can add the extra gain in post without adding audible noise.

I didn't even knew that thing about 24 bit !!

That's because it isn't true.

I suppose if the 24 bit signal is low enough, you will add noise that is audible, but not nearly as much as if the signal was 16 bit.

It is the same.

For example..  If you increase the gain in post processing by 10 dB, the noise floor will increase by 10 dB.  It does not matter whether it is 16, or 24 bits.

This reminds me a little bit of the Spinal Tap conversation - except it is 24 bits and not 11

I think peaking at -12 dB to -6 dB at most is good practice for a new taper (if not all tapers) when recording in 24 bit.

I think we always need to emphasize what sounds best in actual listening, not what we assume sounds best, or what specs might lead us to assume.  And when listening, we need to consider the limitations of our playback.

Any discussion of peak levels is incomplete without mentioning average levels.  Source material varies greatly.   A bluegrass quartet is going to have a very different spread between average levels vs. peak, then rock through a PA.    -12 is a fairly low peak.  Is it too low?  That depends...

[fmaderjr]

Any discussion of peak levels is incomplete without mentioning average levels.  Source material varies greatly.   A bluegrass quartet is going to have a very different spread between average levels vs. peak, then rock through a PA.    -12 is a fairly low peak.  Is it too low?  That depends...

Ok, now I understand where you're coming from. Thanks for explaining why you disagreed and I certainly can't argue with you.

I love bluegrass, but most of my recording has been fairly loud rock and roll so in those cases the average levels are going to normally be  reasonably high when you're peaking at over -12 dB (and often I get to -6 dB) so I haven't had to think much about peak levels.

For example..  If you increase the gain in post processing by 10 dB, the noise floor will increase by 10 dB.  It does not matter whether it is 16, or 24 bits.

But isn't it true that in 24 bit the noise floor can be low enough that raising it 10 dB wouldn't be audible? All I care about is what I can hear.

[datbrad]

Venturing off topic along with you guys, I have found that in practice, it does not sound the same with 24bit to have maximized the bit depth where the peaks are hitting close to zero during the recording, versus running soft levels at the show peaking below -6 and then boosting them close to zero in post. Theoretically it should be true, but my experience has been that it's not.

I am not talking about just noise. I am talking about the overall quality of the signal itself. I experimented last year running one set low, peaks between -12 and -6, and the next set much hotter, peaks between -4 and zero. I boosted the first set in post up to match the second set that was left as it was recorded, dithered/resampled both to 16/44.1, and they were not identical sounding. The second set where the levels were optimal to begin with sounded much better to my ears, smoother, cleaner, or something along those lines.

Except in very select situations where the source is wildly dynamic, or in cases where the situation does not afford you the ability to easily access your deck to adjust, I think it's missing the mark to run soft levels when you are in an open taping situation. I sure don't want to walk out of a show with 16bits worth of information when I had a 24bit recorder. This is just my opinion, of course. To each his own..........

[fmaderjr]

To each his own..........

Yeah-we all should do what makes us happy. My recordings that peak at -6 sound fabulous to me and I'm never again going to worry about keeping my levels near 0 and worrying about clipping.

Since you're apparently a skillful enough recordist to be able to do that, more power to you. I need to be able to keep things simple or recording is not enjoyable for me (as long as the results sound good to me).

You probably have better ears than I do also. I'm getting up in years, so I'm sure I wouldn't hear any difference if I recorded closer to 0 dB anyway. After all, a good Hi-SP minidisc recording sounds pretty much the same to me as a good 24 bit one.