Jump to content

-18dbfs in the Digital domain = 0dB in Analogue? Eh??!


Recommended Posts

Yeah but still, there's an optimum level as there is in the analog domain and it should be meter in RMS. If you're around -9 dBFS and -6 dBFS in Logic, you're safe ok but you don't know what your RMS level is.

And we know 0 dB VU is somewhere around -18 dBFS, so why shouldn't we use that information and meter in RMS when recording ?

 

HALT! Where is your evidence?

 

:)

 

I've asked a lot of times, but you still haven't given a reason for RMS metering on input. I'm also not clear whether you are talking about RMS dBFS or VU RMS (which we've already established is not applicable to digital recording).

Link to comment
Share on other sites

WHOAH! This is getting way too complicated folks. Pull me out of the rabbit hole (winky face!) OK, in a nutshell ('technical speak' to the minimum from me as I obviously don't know what I'm talking about! I thought RMS was the 'average input level', the PEAK being, erm, the peak level!)

 

Put simply, for the last half decade I've been recording too hot & regularly clipping my input. I have now realised the error of my ways and, listening to the advice of others, I'm attempting to make amends for my past recording crimes! Not only have I been recording too hot, I've then gone on to add processing to said recordings & have spent all my time fighting with levels in the red (and that's why everything I've recorded to date has sounded crap!) So I'm back at 'noob' school and now desperately listening to advice on how to do things 'properly' (but the education I have to say seems somewhat conflicting!) I'm still experimenting this end and pleased to say that I'm no longer clipping my levels on input so that's a start.

 

What I now appear to be having issues with is boosted levels from adding plug-in processing effects to individual channels. From my fledgling tests above you'll see that, although not quite clipping, even a track recorded at -18dBfs is peak registering at -3.3dBfs on the Logic channel strip meter when I use the chain example described.

 

Having now read Lagerfeldt's paper on levels (and I quote):

 

"Levels when Processing with Plug-ins: Aim for a peak of around -6 dBFS on individual channels to be on the safe side"

 

If I've recorded my dry incoming signal at ... -18dB? -12dB? -9dB? -6dB? whatever and the processing I've used on that source bumps up that track's channel level to .. -3.3dB? -2.9dB? +1.6dB?(!!) What's the best/proper/agreed way to rectify this and get that level to peak around -6dBfs (as quoted in Lagerfeldt's paper?).

 

BOTTOM-LINE: All my digital recordings to date have been very disappointing. By comparison I had considerably better sonic results when recording in analogue 'back in the day'! (I also had a far better idea as to what I was doing too!) That said, all my analogue gear is long gone & I'm now on a mission & I'm committed to just make things work with my current set-up. (I admit, I just dived into the digital recording side of things and, to date, I've been winging it. For starters, where setting levels is concerned, I wrongly applied what I'd learnt in the analogue field to digital recording which, in hindsight, was completely wrong as it turns out. I've taught myself a lot of bad habits this end but, bear with me, I'm going back to school here! I just want to learn how to do things properly!

 

I just want to finally find out once and for all how to make my stuff 'sound' better so I can crack on with composing & producing music that actually pleases me. Something that I enjoy listening too.

 

Using my above sonic example tests, can someone point me in the right direction on how to manipulate the plug-ins in order to keep processed sound levels acceptable? Many thanks!

Link to comment
Share on other sites

OK, gonna crawl away now (not down said rabbit hole but under a rock for a while!) Yeah, shall put the hours in, do the homework (homework I should have done when I first sold my analogue gear and got my Mac!) Hopefully I'll come back to this a lot more clued up & knowlegdeable - that's the idea anyway! I've just ordered the Logic coursework manual by David Nahamani. Wish me luck & I'll see you on the other side people! Edited by MrSpock
Link to comment
Share on other sites

Watch your levels, use your ears, don't get caught in all this technical stuff.

 

Agreed, thanks Triplets. I don't want to get caught up in the technical stuff - far from it, I want this to be easy as I'm the least technical person out here! The main thing I keep getting 'stuck' with though is this ... I DI record in an electric guitar part for example ie: no software monitoring whilst recording just a plain, dry take. Let's say I have an average input level of around -9dB with the occasional peak of about -6dB (that's OK right?) So now I have my part down and I'm trying to find a sound that sits with the rest of the mic'd stuff I've pre-recorded. I scroll through some Logic library guitar presets such as: 'Classic Rock'; 'British Invasion'; 'Rock of '69'; etc. They all have their sonic merits but why do my levels go through the roof when I've gone to some effort to record at conservative levels? Why am I seeing the processed Channel Strip meter for that track threatening red or in worst cases, actually digitally clipping +0dB? I'm guessing I have to go into each preset and turn down the outputs but ... why? Surely you shouldn't have to do this with actual Logic presets? I can understand 3rd party plug-ins that aren't specifically calibrated for Logic but I still don't get (nor accept) why Logic's own built-in presets have this annoying habit of sending my tracks into clipping danger zones - it just seems unnecessary (not to mention confusing!)

Link to comment
Share on other sites

Just to echo a few choice nuggets of wisdom.

 

Don't clip your inputs when recording or final (master) output...... unless you like the way that sounds - cause every rule is made to be broken!

 

Manage your plugin gain staging as needed by inserting a gain plugin where needed or adjusting the input/output gain on the plugin itself (if available).

 

Emulations like amps are definitely twitchy about gain staging since they are designed to mimic the behavior of an analog device that was itself designed to change tone based on the input level. Think about how an amp's tone can be changed by turning up a guitar's volume knob. That's the same as your hearing in Logic. A track recorded at lower volume doesn't push the plugin(s) quite as much as a hotter track and so the tone changes accordingly.

 

This explains the "purity" you hear in your voice when recording at a lower level. Part of your chain is a compressor and to simplify things a bit, we'll only look at the compressor action. With the quieter track, the compressor isn't getting hit as hard, so its not compressing as much, leaving a lot of more of the natural transients and dynamics in your voice. The hotter track is causing the compressor to level or smooth out a lot of those characteristics that are more natural sounding, which leads to a less "pure" sound. Neither sound is inherently better than the other - its all about what you think sounds good.

 

If you haven't actually clipped any of your older recordings and want to play with techniques, try inserting a gain plugin as the first plugin in the channel strips of some older projects and start lowering the gain. If you assume that you would sing or play the track the same way and would have just recorded at a different level, then adding the gain plugin is going to produce a sound that will be very close to what you would have gotten had you recorded at a different, lower level. The previous statement assumes that you are going direct to the converters, not clipping and are not extremely quiet in parts (ie have a huge dynamic range like an orchestra).

 

cheers!

dorian

Link to comment
Share on other sites

If you're recording dry electric guitar DI, I'd say based on my own experience you're better off taking full advantage of all the headroom 24 bit recording gives you. It's totally OK for your DI signal to be on the quiet side before you add all the sims and plugs to it.

 

I've been playing around with my guitar presets lately and I've got a lot of them set up to just plug in and play, so I checked what my levels look like with the plugins removed: for the most part I'm hitting in the -18 to -9 range (peaks mostly at -9). I adjusted my interface input volume so that my interface meters hit yellow only on the hardest strums. Most of the time if I'm picking or playing with my fingers the signal might only be -18 or lower. This is a setting of 6 out of 65 on my Duet 2 instrument input, to give you an idea of how modest the DI can be. It sounds perfect once the plugins are added into the mix.

 

I can see how it would be hard to monitor dry when you're recording though, you might be better off loading up a very basic clean amp sim and monitoring through that (or even better, monitor through the tone you want in the end if your computer can handle it).

Link to comment
Share on other sites

That's again Steveo - that's a great help mate! I think I've (finally) discovered what's been causing me such consternation. I finally discovered the electric guitar I HAD been using (NB: past tense!) had a battery 'under the bonnet' (this is refered to as being 'active' I have now learnt - told you I wasn't very technical!) Turns out this was a contributing factor to my problems this end & making it really hard for me to tame my levels. Said guitar has now been traded in (for a nice Fender!) and, from my first formative recording experiments with the new guitar, I'm pleased to say that my input levels are a lot more manageable!

 

I now intend to follow your excellent advice & make notes on what level(s) to set on my interface in order to enable the ability to just plug'n'play as you say - I like the idea of that ie: just having everything set to go with no faffing about which can lead to losing a moment of inspiration (I don't have a very long attention span!) My hope is that, over time, the means of production becomes almost invisible order for me to be able to concentrate more on more on the most important bit ie: 'THE MUZAK!' (This is the plan anyway!) THANKS AGAIN!

Link to comment
Share on other sites

Quick question Steveo (or anyone else out there who might like to chip in!) I've been doing some preliminary tests trying to find some goto input settings on my interface. Thanks for all the tips! Once you've added all your sims/plug-ins to your captured guitar tracks, approximately whereabouts are you hitting level-wise on Logic's individual Channel Strip meters? What do you aim for roughly? For example: -9dB? -6dB? -3dB??

 

PS: I've also happen to have been experimenting with a borrowed-from-a-friend new gadget, namely a YAMAHA THR10 USB amp. It's a pretty cool gizmo as it turns out with some rather convincing built-in valve (emulation!) sounds.

 

With this one you set Logic to recognise the THR as your input interface then just create a new empty track (no plug-ins/processing) and set the i/o to Input 1 for Mono (or Input 1&2 for recording in Stereo). Using a sort of 'old skool' technique you 'find your sound' PRIOR to recording then, once you have a sound you're happy with (there's some pretty convincing built-in effects on this little amp too!) you just hit record, play in your part and you're done!

 

The good thing about this is that, if you've got your tone right, you're hearing decent sounding guitar input with no latency. The downsize I guess is that you're 'printing' your sound to tape (sorry HD - old habits die hard!) so it's fixed - you can't alter it much post-recording like you can with Logic guitar sims/plug-ins. As is always the case, there's Pros'n'Cons you have to way up working like this but, from my tentative try-outs to date, I'm fairly impressed with the sounds coming out of this thing! It's perfect for a late night jammer like myself who can't crank up a Vox/Marshall & mic it up in the traditional manner due to being surrounded by irrate neighbours (yes, I've been there before!) I'd recommend trying one of these THR amps for sure! Don't get me wrong, some of the sounds you can coax from the Logic guitar sims are great (especially for clean tones!) but, if like me, you occasionally hanker for some of those big, 'Classic Rock' valve-like geetar tones (but can't 'shake the walls' in order to find 'em) this little Yamaha amp will get you pretty much 75% of the way there! Anyway, I digress ....

 

With a pre-dialled in tone/effects coming in via USB that, by rights, shouldn't need any further processing at the mix stage, again ... what levels should I be aiming for on these kind of tracks would you know?? Would an input max. peak of say, -6dB be a good place to aim for would you say? As always, interested to hear back on any thoughts here ....

Link to comment
Share on other sites

After the amp sims it really shouldn't make much difference as long as you're not clipping. I usually play for a bit and see how often I'm into the yellow; more than a few peaks here and there and I'll turn the output down in the plugin.

 

By the time you start working that track into a mix its fader is probably going to get turned down quite a bit from where you start with just guitar. The fader level can and will change depending on what your mix requires, but the important thing is just not to clip anywhere along the signal chain within that channel strip. So there's nothing wrong with being conservative within the channel strip and then pushing the fader up later to balance things in the mix.

Link to comment
Share on other sites

  • 6 years later...

And at last, if you want to measure it, you can ! Send anything with a constant level in the input of your choice at -18 on a Logic track and then insert on that track a VU Meter plugin. If it says 0 dB, your audio interface is "calibrated" at -18 dBFS. If not, adjust the level until it says 0 on your VU Meter to find out.

 

So I did this (put gain plugin at beginning of strip) and increased it until I was averaging around 0 VU on the Waves VU meter (I have the "headroom set to 18 on VU meter). So 0 in Logic's fader meter = -18 VU. I thought that each logic track (to start a mix) should be around -18 / -15 dB in the fader meter, and have been leaving about -6dB headroom in my logic meters... that makes the VU meter come in around -5 VU... I'm more confused than I was when I started lol.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...