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Subject:compression, what's all the hype
Posted by: quadjacks
Date:7/5/2004 5:08:33 AM

i am still really struggling with all the hype of compression, i run sound for my church using the mackie efx 16, i am using sound forge to record. sometimes the mix is very low, so i thought there surely is a way to raise the volume levels of the final mix before burning. i have read the manual of what all the levers, buttons, bells and whistles MEAN, but i'm really struggling on how to actual put them to work. but not just get them going but maybe push them to the edge. could someone please break down all the different sliders on which ever will prove to be the best way to raise the volume, whether it be wave hammer or the dynamics | multi-band tool. i have read here, mixed emotions on those two compression toolz. please help me understand what the levers mean; threshold, ratio, attack time, release time, smart time, etc. in wave hammer. and RMS i understand what is does but i am stumped on the whole release and attack time thing. your help will be greatly appreciated

Subject:RE: compression, what's all the hype
Reply by: johnnystunt
Date:7/5/2004 8:17:23 AM

you can try this link to provide a starting point, it will probably clear some stuff up for you.

http://www.prorec.com/prorec/articles.nsf/articles/B425578C027460898625661000745390

Subject:RE: compression, what's all the hype
Reply by: Rednroll
Date:7/5/2004 8:26:19 AM

Here's a couple posts of mine that you might find useful with information on all the controls of a compressor and also some recommended multiband compressor settings.

http://mediasoftware.sonypictures.com/forums/ShowMessage.asp?ForumID=19&MessageID=290122
http://mediasoftware.sonypictures.com/forums/ShowMessage.asp?ForumID=19&MessageID=252230

Subject:RE: compression, what's all the hype
Reply by: quadjacks
Date:7/7/2004 6:47:34 PM

so let me C if i am understanding U'all correctly. 1st i load my file into SF7.0, 2nd i run the TOOLS|STATISTICS tool to C where the largest and smallest of the dynamics are in the file. my file says the maximun sample value is
-3.43db, minimal sample value is -3.8db. 3rd i use the wave hammer tool, setting my THRESHOLD TO -3.8db, cause i want my whole file to match this dynamic range, not sure on the RATIO, so i set it to about 3.0:1, with the output gain set to 9.7db, the file is really low. ATTACK TIME is 10ms, RELEASE TIME 50ms, didn't bother with the SMART RELEASE, dont really understand it :(. 4th i choose selection, then from the drop down choose, ALL SAMPLE DATA, ok then ok. zip zap, i have this new reading of minimal and maximun 0.01db. so what i figure is i find the lowest dynamic, bring everything above that down to the minimal, then using the output gain raise the volume of the whole file without raising the all ready loud parts. WOW. did i do well ??? that brings me to what is considered to be a MASTERING step or tool, are they found under the PROCESS and EFFECTS options at the top of the proggie ???

Subject:RE: compression, what's all the hype
Reply by: Rednroll
Date:7/7/2004 8:10:42 PM

"my file says the maximun sample value is-3.43db, minimal sample value is -3.8db."

What have you done to this file already!? This is a maximum dynamics range of .4dB.....that is rediculous. This song is beyond mastering help. It sounds like you have already wavehammered the death out of this song and killed any resemblance of having dynamics. There is no step by step process in mastering, just some guidelines, and tools to achieve a result that YOU are trying to achieve given the current sound of a song. It's like mixing, you can't be told Step 1 raise kick drum to -15dB, Step 2 raise Snare to -12dB, Step 3 Pan Guitar hard right. Each song has it's own characteristics and feel that you are trying to achieve in a mix. The same is true for mastering. The best thing you can do is read up on some mastering guidelines and tips, then begin to practice...practice...practice...and eventually you will develop some skills and favorite tools to achieve what you want. Try extracting some professionally mastered CD songs and run some statistics like you did on your song, and you will see how far you are off in comparison to what your song statistics show. From the statistics you've posted, this song should fatique your ear after listening to it for 30 seconds and probably sounds like one big wall of distortion. There are all kinds of tools in Sound Forge for mastering located under every menu....it doesn't mean you have to use all of them. You need to be experienced enough to listen to a song and be able to pick which tool the file needs to be applied by knowing what each tool does. Right now you're asking a question like, I have a tool box, I want to build a house, which tool do I use first? I have a sledge hammer, will this drive a nail into a 2x4?

Subject:RE: compression, what's all the hype
Reply by: quadjacks
Date:7/8/2004 5:10:48 AM

i'm not sure i understand. when i ran the statistic it stated that my
minimum sample value (negitive) -3.40db left channel, (negitive) -3.38db right channel.
maximum sample value (negitive) -3.43db left channel, (negitive) -3.42 right channel.

that was the original file after recording. i had not mastered it yet, or as you put it MASTERED IT TO DEATH.
so are you saying my recordings are all wrong. i am not able to record each channel seperate , dont have the funds for that , just yet. the file contains an entire mix, about 10 channels.

after i ran wave hammer i got a (negitive)-0.01db on both channels.

i did run statics on a pro. fred hammond, he has about 18 albums under his belt, and i would think a guy with over 7 albums gold(GOSPEL MIND YOU) has the engineers to master correctly. his mix has (negitive)-0.00db, not so different from mine.

man you pissed on me, but it's kewl. i'm the green dude. i can take it.

Subject:RE: compression, what's all the hype
Reply by: Rednroll
Date:7/8/2004 10:02:15 AM

I didn't mean to piss on you, but I think you have something screwed up in your explanation, or in getting the statistics information.. Maybe, you should run the statistics again and relook at the "minimum sample value" again. There is nothing wrong with your maximum sample value and that could actually stand to go up a bit in volume.

You are saying that your song has a minimum sample value of -3.40 dB, and a maximum sample value of -3.43. That means there is a volume difference of .03 dB=(Max-Min). That means there is a maximum dynamics range of .03dB. If this information is correct, there is something definately wrong with what you are doing. When you ran statistics on your pro friends mix, what was the "minimum sample value"? When you run the statistics are you making sure you have the entire song selected? The statistics only runs on the data you have selected, so I'm guessing you don't have the entire song selected when running statistics or there is something seriously screwed up with your mix. If this is the true statistics, this resembles more of something that would be a DC voltage type of signal rather than an AC audio signal.

Subject:RE: compression, what's all the hype
Reply by: quadjacks
Date:7/8/2004 7:31:20 PM

before mastering i get the following

minimun sample value: -22,161 (-3.40 dB, -67.63%)...left channel___-22,207 (-3.38 dB, -67.77%)... right channel

maximum sample value: 22,067 (-3.43 dB, 67.34%)... left channel___22,114 (3.42 dB, 67.49%)... right channel

and yes i am running statistic's on the whole file the cursor is is on the far left of the file.
heck i even tried highlighting the entire file... same statistic

am i recording to low ??

can i email you some screen shots ???

you said "this resembles more of something that would be a DC voltage type of signal rather than an AC audio signal. "

i read this

DC offset occurs when hardware, such as a sound card, adds DC current to a recorded audio signal. This current results in a recorded waveform that is not centered around the baseline (-infinity). Glitches and other unexpected results can occur when sound effects are applied to files that contain DC offsets. Sound Forge can compensate for this DC offset by adding a constant value to the samples in the sound file.


i do get a slight bussing sound while i am recording. could this influence this ??

Subject:RE: compression, what's all the hype
Reply by: wobblyboy
Date:7/8/2004 8:10:54 PM

Hey guys, I just use the tools and trust my ears. When it sounds right it is GOOD.

Subject:RE: compression, what's all the hype
Reply by: Rednroll
Date:7/9/2004 7:55:36 AM

Definately, the buzzing noise can be contributed to a high amount of DC offset. Try using the remove DC offset tool in Sound Forge, then run the statistics. If you find your maximum sample value has greatly reduced, then you definately have a DC offset problem, and you'll probably want to trouble shoot that before doing anymore recording. Send me a screen shot of the waveform and I'll take a look at it. Try to make it a jpeg under 200k in size. Send to REDNROLLatHOTMAIL.COM. Replace "at" with @.

Subject:RE: compression, what's all the hype
Reply by: Rednroll
Date:7/9/2004 8:07:32 AM

"Hey guys, I just use the tools and trust my ears. When it sounds right it is GOOD."

Yeah, and that's very helpful. I saw your post in the Vegas audio forum about recommending wavehammer to increase levels for mastering. I recommend you look at some other tools, that are better suited. Wavehammer is a great one button push volume maximizer for those not so familiar with mastering, but an engineer who has done a fair share of mastering will never regard your recommendation as serious mastering. It may be sounding right to you but your ears don't sound like they're so well trained on other aspects that you may be overlooking, like spacial characteristics , compressor pumping, distortion added on high frequencies instead of a smooth full pleasant sound, lack of air in the song causing ear fatigue on extended listening.

Subject:RE: compression, what's all the hype
Reply by: quadjacks
Date:7/9/2004 7:40:54 PM

yeah... that took me down to max sample value -1.91dB.
after recording what should my statistic be ??
where should i begin my troubleshooting to find tht buzz?
also where can i learn what tool to use, i mean there is so many, how will i ever know what they all mean and when i should use them?
is there any books you can recommend me too ?
or is there a class i could take ?
you have my meter off the chart....
my file is so low when i burn it, i thaught wave hammer was the best way to raise the volume, but you spoiled that. so what is the best way to raise the volume ??

Subject:RE: compression, what's all the hype
Reply by: Rednroll
Date:7/9/2004 11:30:13 PM

The first tool you might become familiar with is PROCESS>NORMALIZE

You can use "peak" nomalization and set the value to 0dB. This will scan the entire file and find the max sample value and then raise the volume of everthing so the max sample is at 0dB. This is usually one of the last steps in mastering.

Don't get me wrong wavehammer is a good tool and has it's uses, to bring your overall average RMS volume up. A better tool to do this is multiband compression. With a multiband compressor you can compress LOW, MID, High frequencies in different amounts to bring the overall RMS volume up. This is something that Wavehammer doesn't do. If you use Wavehammer to bring your RMS volume up, it will overcompress the high frequency ranges, which should get the least amount of compression when you are using compression on an entire mix. Side effects of this type of compression is some nasty distortion on the high frequencies, because the high frequencies are the majority of your peaks, because of transients. Thus, if you use Wavehammer to bring up the overall volume you should use it conservatively, instead of using it for most of bringing up a low level song to todays standards. If you use wavehammer alone, you will get a loud song....Loud is not hard to achieve with todays computer software tools...it's getting it loud, yet maintaining the quality of the mix with the least amount of side effects. It's not hard to achieve, it just takes some experience and practiciing. You can also use Normalization and use "RMS Normalization". Try a -12dB to -10dB RMS Normalization, and you can get a pretty loud file. If you are looking for a simple one button push mastering type of process, RMS Normalization and Wavehammer are ok choices, but won't give you better controls like a multiband compressor will.

My personal opinion is that everyone has the ability to get their hands on powerful software to do near professional type of audio work. Very little people just starting off know hardly anything about how to achieve good sounding recordings as compared too when you buy a commercially released CD. They know nothing about the "art" of mastering and don't seem to have the patience to learn. Thus, the development of tools like Wavehammer and Waves L1 compressors. I like to refer to these 1 button push plugins as "mastering for dummies". Whereas, more proper tools for mastering is a combination of a multiband compressor, Equalizer, and limiter....these are the fundamental tools, then you can get into other things like spacial enhancers, and tape compression. Getting around to properly knowing how to adjust each of these tools, takes some experience and some reading.

"is there any books you can recommend me too ?"

Start here.

http://www.tcelectronic.com/TechLibrary#LoudnessControlandMastering
http://www.musicbizacademy.com/articles/gman_mastering.htm
http://www.digido.com
http://www.izotope.com/products/audio/ozone/guides.html

I would also recommend getting a subsciption to "EQ Magazine", "Electronic Musician" and/or "Mix". Each of these have articles every now and then that describe mastering and other recording guidelines written by professionals. Eventually, after reading a few articles you will start to pick up on basic guidelines between them, and after awhile start developing your own tricks.

"where should i begin my troubleshooting to find tht buzz?"

Please describe your recording signal path from start to finish. I need to know the devices you're going through. You need to include inputs and outputs of each device and the type of input/output it is (ie balanced/unbalanced/Digital). Also describe the type of cord you are using to connect the different devices. ( ie 1/4" mono to RCA....1/4" Stereo to XLR...etc.)

Subject:RE: compression, what's all the hype
Reply by: quadjacks
Date:7/12/2004 9:45:12 AM

i am using a regular old soud card, sound blaster pci 128. cant really afford a real card right now, any suggestions on a good card?

i had just formated the pc and didn't get the right drivers for the card. i noticed that without even having the line plugged into the board(mackie cfx16), my meters where going up and down, like something was going on in the back ground. i would select another input source other than line in, and would still get the meter going. but when i loaded the new driver the meter stop going. so i think i fixed the DC issue.

Subject:RE: compression, what's all the hype
Reply by: Rednroll
Date:7/12/2004 11:36:34 AM

The Sound Blaster cards are notoriously noisy for recording. For a more professional recording card I would recommend anything by Echo. WWW.ECHOAUDIO.COM. Others have had good luck with M-audio cards too. www.midiman.com

Subject:RE: compression, what's all the hype
Reply by: metrazol
Date:7/13/2004 12:45:12 PM

Rednroll and quadjacks,
This is one of the must generally helpful threads on right now, too bad it's b/c you're having problems, quad. I'll chip in with just a couple points.

First off, record at an overall lower level. You're hitting peaks of -3/-4. That's awfully hot, I usually aim for -12 tops, since you can always bring sound up, but repairing that clipping....sigh...
Also, it'll help your range since you'll have more room to bring up the loud stuff and leave the quiet where it's supposed to be. Noise Reduction before amplification does wonders compared to after.

Also, maybe ditch the PC for recording? You have much more control with doing good ol' DAT, MD, or even hard disk transfers, and a small portable recorder isn't very expensive. DAT is getting danged cheap now, and it's still a fabulous format. I'd even say get a Nagra (they're a hit with the ladies!) but 1/4" tape is becoming hard to find and I don't know if even I remember how to load quickly... I do half my recording to PC, and the other half to my PD-4 and the flexibiility comes in handy.

Otherwise, Rednroll is pointing you in the right direction so well I've learned a ton from this thread. Good luck with the ol' recording.

Subject:RE: compression, what's all the hype
Reply by: quadjacks
Date:7/13/2004 7:25:43 PM

hey thanks metrazol... but you have opened a new can of worms. the different recording methods sound complicated. my budget is very slim seeing that we are building a new church soon and i cant get the finance dept. to budge. but now that you have mnentioned it, please enlighten on the various optoins to recording. the main reason i record digital is so i can burn cd's of the days mesage before service is over. you know, catch the folks before they leave.

Subject:RE: compression, what's all the hype
Reply by: Rednroll
Date:7/14/2004 8:43:47 AM

There's nothing wrong with recording to a PC. It will make your life a lot simpler. Record/edit/mix, all in a box smaller than a DAT machine. Why would you make your life complicated by recording to one format, only to transfer to another so you can complete the job? You have tons more flexibility on the PC for recording options also. 24bit, 96Khz, how about 196Khz sampling frequency capabilityYou won't find a high resolution audio Dat recorder or mini disc recorder. Afterall with audio it is about the quality isn't it?

Another thing I don't completely agree with is the recommendation of -12dB tops on recordings. It is a good conservative level to recommend and is probably better than risking distortion. But if statistics shows the max sample value at -3.4 dB, then your audio has no digital distortion due to going past 0 dB peak. There's only a posibility of distortion happening in the analog signal path before the audio went through the A/D converter. I recommend to aim more for -6dB. In digital audio you can equate 1 bit of resolution per 6 dB. Therefore if you are recording at 16 bit resolution, and you are peaking around -6dB, this means you are using all 16 bits, therefore giving better resolution to your recordings. lowering it to -12 means you're using 15 bits max. Also with a -6dB setting, your sound source can go twice as loud before it hits the 0dB ceiling, so you've got some good headroom to work with. It just depends on your source. For some stuff I'll error on the conservative side peaking around -10dB, but for something that has pretty controled dynamics I aim more for the -6 dB peak area.

Subject:RE: compression, what's all the hype
Reply by: quadjacks
Date:7/14/2004 6:57:05 PM

i kindof thaught i was doing it the best way for me. burning cd's before the folks leave the church is the BOMB.

Subject:RE: compression, what's all the hype
Reply by: metrazol
Date:7/20/2004 11:44:09 AM

Rednroll, I accept your input and bow to your studio experience. I'm used to good ol' production mixing and well, it's never fun to say, "Uh, can we do another take...I sorta...uh...hey...I'm fired, aren't I?" I always use a lot of headroom but you're right, it's usually never an issue...as in 99% of the time...but better safe all the time than sorry....01% of the time...which they'll loop anyway...

And about the size of DAT Recorders...don't make fun of my PD4! It's big for a reason! Fostex just never felt the need to, ya know, say what that was...maybe so they can have such big buttons...Sigh, the switch from lugging a DAT around to studio is still painful...

Quadjacks, I'd love to hear how you burn those CDs, as in your quick production chain, b/c it's something that's come up around here but I've never really put much thought into doing it.

Subject:RE: compression, what's all the hype
Reply by: Rednroll
Date:7/20/2004 2:39:59 PM

You have a Fostex Dat recorder?....those are huge and heavy. We had one in a studio I worked in and it got lugged around from studio to studio, just for the fact it could input/output smpte from the Dat. I'll stick with my Panasonic SV-3800. I agree with you 100%, on always better to error on the safe side. In my studio when I record voice over work, I am always recording to DAT and to the PC at the same time. It has saved me many times, I'm sure everyone has had a PC freeze up on them in the middle of a take. Headroom failsafe is also a reason I have a compressor in the signal chain when recording live instruments to turn those runaway peaks down to a controlable level. You're right with the -12 dB recommendation, that's very near my -10dB conservative setting, but I'll aim closer to the -6dB on sources that don't have a wide dynamic range knowing that sound can go twice as loud and then some due to having a compressor in the channel.

I'll tell you though at this point in recording technology along with a Windows XP Pro operating system, I've had more Dat players eatting tapes, being slightly misaligned causing them to not play in other playesr, than PC crashes, so I'll choose the PC over a Dat player anyday now. To me the PC is the main recording device, where the Dat player is my fail safe. I've been raised on recording on 2", 1/2", 1/4", then to Adat, DA-88, and Dat, so I've been there too.

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