Readers' Letters: The difference between linear and nonlinear distortion, and more...

David Mellor

David Mellor is CEO and Course Director of Audio Masterclass. David has designed courses in audio education and training since 1986 and is the publisher and principal writer of

Monday December 17, 2012

In response to The difference between linear and nonlinear distortion, Dan writes...

i know this is an old post but you really should remove it. the terms linear and non-linear are very well defined mathematically, especially regarding signal processing. you have created your own definitions and they aren't the 'correct' ones.

RP response: On the contrary, these terms have been widely used in this way and are certainly not the invention of Audio Masterclass. Mathematicians don't have a monopoly on language.

In response to I used to have a purpose-built, soundproofed, acoustically treated studio, now I don’t., Andru writes...

I have to agree with your article, "Is a Studio Really necessary.."

I too have swung from a room in the house to a "complete studio", and well... sometimes you just get more done without the pressure of the bills etc...

For the last couple of years I have been using the double garage connected to the house... it is not ideal. So I am thinking about a separate structure for my studio... Yes I will have to relocate... but what the heck. I don't really like being so accessible to my family (kids) while I am trying to work... breaks the flow. So, do I just want to hide in the studio? Hmmm, perhaps, sometimes... I guess we all need our little dreams to keep our momentum...

Just to add that I like the philosophical approach to David's view on recording in general, as we all know... or learn.. it is so easy to be caught up in the all toys that will "make us special"... when in actual fact it is the feeling inside of us and how we view the world, related through our creations, that helps make us different.

Thanks agin for a great website!


In response to The Digidesign ICON - is it the most expensive mouse in the world?, Randall Harris writes...

I am a student at Western Carolina University in North Carolina. I am a bit biased because I have been using a C200 SSL consol for a few years. We run pro tools HD3 as weel. I feel that an ICON system will never be able to stand up against a big console such as a neve or SSl, but as far as standard audio recording goes, if you use pro tools. the ICON is the most affordable way to be competative in todays music world. That is were it ends though, I would love to see an ICON try and tackle a broadcasting situation, where you have multiple mixes, dozens of aux sends, and mix minus. I give alot of credit to digidesign, they have filled a void in the audio recording world and are still on top, but you just can't compare ICON with large consoles, they are completely different things. You can take a large console anywhere and integrate it into any situation, but take the pro tools software away from the ICON and you will find that it is a completely usless board that doesent even have audio paths in it. ICON is a great idea, but at the end of the day ICON is not a console so it should not be compared to real consoles.

In response to Why do microphones sound different?, CE writes...

When you play back your recording of the mic, how do you know the speaker on playback didn't change the "perfect" sound from the mic...which comes first the perfect mic or the perfect speaker? And what about the room influence of the original recording, and then the room affecting the NEVER ends........and if ya keep thinking about it, your head will spin off your body.......aaaaarrrrrrggggghhhhh. Then what did the perfect recorder do to the perfect signal from the perfect mic? Double aaarrrggggghhhh

RP response: Just keep calm and the spinning will stop. It's a fun test to try out though and it usually demonstrates the inaccuracies of the signal chain very clearly.

In response to Believe me, you WANT to buy THIS microphone..., Pete LeRoy writes...

Two things to bear in mind: good as it is, this mic may be totally wrong for your voice. And while you're looking at modern mics, don't forget the AKG SolidTube.....WOW!

In response to The worst item of equipment in your studio is the one you rely on most. Why?, Entoine writes...

It is the kind of feeling I had when first hearing Adam Monitors which have Ribbon tweeter, I thought that the sound was so "here" that there were no monitors anymore.

In response to The worst item of equipment in your studio is the one you rely on most. Why?, CE writes...

It also proves that DSD IS the defacto format for recorded music.....and DSD sounds better on any type of speaker. Everyone should be recording and playing back in DSD.....see how real it sounds......

In response to The worst item of equipment in your studio is the one you rely on most. Why?, Dr. Andrew Colyer writes...

Great Article!

1 = How do I get some of these electrostatic speakers, and how much to they cost?

2 = Who's the fine looking woman in the leather pants standing next to the speakers?


RP response: 1. eBay! Be quick, the price is going up.

2. Click on the photo in the article...

In response to The worst item of equipment in your studio is the one you rely on most. Why?, Pete LeRoy writes...

Speaking of alternative speakers, I've been dying for someone in the studio biz to do a serious review of the BOSE tall column speakers.

In response to The worst item of equipment in your studio is the one you rely on most. Why?, Gerald Lopez writes...

most recordings Aren't made to be reproducing the actual sound of the instrument, modern rock and pop recordings anyway.

have you ever been in a room with a drumset that sounded anything near a record? and it is al about how the consumers are going listen to it at home.

In response to Why do microphones sound different?, Craig7 writes...

Thank you I love the fact that your not trying to push your version of excellence and acknowledge that its is that difference that inspires creativity.

(so to speak)

RP response: Audio Masterclass policy is that there is no one 'right' way to do things in audio. Certain factors, such as frequency response, distortion and noise, will always be fixed points. However, pretty much everything else is subjective and up for grabs.

In response to The BBC to axe background music? Less work for composers?, A Gunning writes...

Television and film background music should only be played when there is no speech. It is very annoying and distracting when music dominates an actor's speech. Only recently I was totally unable to hear what two actors were whispering to each other because of the unacceptable level of background music. There is a time and place for music, but not when there is speech.

RP response: Finding background music too loud can be indicative of hearing loss - one test for hearing loss plays speech against background noise of varying levels. It may of course also be possible that the background music was just too loud.

In response to Which loudspeakers are best for accurate monitoring?, Jeff Connors. writes...

I purchased a pair of PMC TB2SA's without even knowing they were in fact total different technology to all the other monitor speakers I had used over the years ! Went along to the retail outlet with my own ref. CD in my hands and a kind of "audio image" of what i wanted to hear,in my head.The very patient chap at the shop then let me listen to the same track off my ref. CD on ten different sets of monitors. I went back to the shop three times and repeated the process....I was determined not to buy a set that would dissapoint in the future!....Each time I could not get over the clarity and attention to detail that the PMC's gave to the ref. music.....I only found out they were "transmission line" after reading the manual. I have been using them for nearly two years know and all the mixes I have done translate beautifully to other sets of monitors/ Hi Fi set ups....and more importantly,the old tried and tested in car test!!....For me it would be hard to go back to normal speakers although i do have a set of passive Alesis Monitor two's and a vintage set of Scott Hi Fi speakers for comparison the PMC's seem to give that uncoloured or enhanced sound that we all search for in our main monitoring speakers !.......PS..I don't work for PMC by the way !!

In response to The worst item of equipment in your studio is the one you rely on most. Why?, Keith Kurtiss McIntosh writes...

Since I doubt that many of us have the money or the space for your 'electrostatic' speakers, and you've admitted that people won't be listening to anyone's mixes on them in the first place, exactly what was the point of the article? Given the facts you yourself stated in the piece, the whole bloody thing is MOOT! Sorry, but you've got to do better than this!!

RP response: Clearly you have a closed mind. Sorry we can't help you.

In response to The worst item of equipment in your studio is the one you rely on most. Why?, Stephen Balliet writes...

Yeah right I thought as I started to read this article. Cut to the chase I am listening to Quad 2905 speakers. Perhaps the most uncanny quality is how realistic some recordings can sound from outside the room. At about 1/3 the $40 K speaker cost they are still far from inexpensive and far from perfect. The comment about expecting if not wanting a speaker to sound like a speaker is very true. Having lower distortion than any other speaker they can be very revealing, but they can not load or pressurize a room with bass energy the way even some modest speakers can. Saturday night dace party they just wont do, but Sunday classical in the afternoon can't be touched by any other speaker. Still for this kind of money you would think they could do better than a cheap bipolar electrolytic DC blocking capacitor as the first thing directly in the signal path. But then if there was nothing to improve what would we do just sit back and enjoy the music?

In response to Why you should have a drum set, even if you can't play, Shawn Rafferty writes...

I got a Yamaha DD55 a few months ago with just this sort of thing in mind. Having gone for years thinking I couldn't play drums, something I could use with headphones so I wouldn't feel self-concious getting started made a big difference. I'm still not a "good" drummer, but I've gotten a lot better!

In response to The worst item of equipment in your studio is the one you rely on most. Why?, Bill Baird writes...

I have worked in R&D in audio for many years and make and use electrostatic drivers so am well primed with the pros and cons of the units, the "63" form of quad is an exceptional driver HOWEVER it is EXTREMELY restricted in dispersion in the upper mid and HF band,they also benifit by being directly coupled to the floor (Screwed down hard) or increased substantilly in mass to avoid rocking - I agree the unit sounds exceedingly close to nature - the detail recovered is exceptional due to the miniscule mass of the air exciting diaphragm and this factor adds dramaticlly to the detail - good ionics are a similar step change.

Have fun bill baird.

In response to 'Reverse latency' - is there such a thing? One Audio Masterclass visitor seems to have a problem..., Ron writes...

Reverse Latency

This may not be Nats problem but I offer it anyway.

I recorded an interview on a DV videocamera and also close-mic'd the subject using an iKey sound-to-mp3 device as a second recorder.

When I imported the mp3 file into a video-editing program as an auxiliary audo track, the speech matched the video for about 30 seconds before it became obvious that the sound was drifting apart. At the end of a 10 minute interview the speech was about sixteen seconds out of sync.

Luckily I was able to drag the timebase of the aux audio track to match the end point of the audio on the main video track.

What this probably means is that the audio track on a DV camera is straight analog recording and the mp3 file was a compressed timebase, but in practical terms it means that in my case, the sound on video has a different timebase compared to an external recording using iKey mp3 recording.

Playback on both sounds natural and its only when comparing a long recording that you really see the error as in Nat Lyea and his work.

Maybe he has a similar effect going on.

RP response: We have all become accustomed to digital equipment syncing easily. However, any two independent digital recording systems will drift apart sooner or later. How quickly depends on the accuracy of their clocks. 30 seconds is pretty quick though, so clearly there is something more than a simple clock accuracy issue. When it comes to resyncing, we've been there, done that and hope never to have to do it again! But we probably will...

In response to The worst item of equipment in your studio is the one you rely on most. Why?, Avi (the Rebel) writes...

I have decided to play the devil's advocate on some of the pretentious articles I get such as the "The worst item of equipment in your studio is the one you rely on most. Why?"

Why do we need to buy the most expensive monitors?

This strikes me as opposing shear logic and ignoring the current state of affairs.

The concept of "truth" monitors is archaic and belongs 20 years ago when people were listening to music through Hi-Fi systems and speakers. The truth of the matters is that today – apart from few audiophiles – most people listen to MP3 music through tiny earphones or at best through PC or car speakers!

So do we really need expensive – highly accurate – monitors ?

or should we in fact adapt to our times and use simple speakers for mixing music?

More than that, I dare to say that "truth" monitors can derail and lengthen the mixing process. I think that any home recorder have faced the "truth" monitors effect. Namely, the mix sounds great on the "truth" monitors but lousy on other stereo systems! Am I right or am I wrong?

Try using simple monitors for mixing, you would be surprised how good it gets and moreover how cheaper it gets!

And one more thing, always check your mix in mono!

Away mastering, away expensive monitors.............

RP response: Thank you for your lengthy reply concerning our 'pretentious' article, which clearly you didn't read all the way to the end...

In response to Can you help? My M-Audio Audiophile 2496 isn't working, Josa writes...

Hi Try changing the wave output to monitor and down load the new driver from m audio. Configure your computer default sound setting,from the control panel window, clk on the speaker audio icon and set up your default, audio and midi recording default, cheers

In response to What is a 'Class A' amplifier?, Phil Georges writes...

This article seemed to be commenting more on an amps symmetry, than it's class. To me it prompted the question, So is it the standing current that is the issue as far as class a or B is concerned? thanks

RP response: The standing current defines the class. Symmetry in Class A amps is a separate but significant issue.

In response to Play too loud and we'll cut the power!, Montgomery Fox writes...

I had this problem in one venue I played- even the quiet support duo had power cut, due to the (acoustic)cymbals! Solution: run power via a long extension from an ajoining room (kitchen in this case), where the cut-out circuit is not in line...

RP response: Brilliant solution! We approve.

In response to The worst item of equipment in your studio is the one you rely on most. Why?, Prem KM writes...

Article 'The worst item of equipment in your studio is the one you rely on most.Why?'has made a great change with one of my friend who belived on conventional speakers only for monitoring.Thank you .

In response to Is your producer trying to steal half of your royalties?, David Foster-smith writes...

perhaps a way to make this fair would be to declare exactly what the contribution was at the PRS or wherever then if the big producer has received 50% for going "doo doo doo" in the background (true story)on top of his session fee, then they could become the subject of ridicule via the seious music press.

In response to The shocking truth about working in pro recording studios, David Foster-smith writes...

these rules you say are normal are childish arrogant and immature.Not all high end studios behave in that manner and the attitude described deserves derision and disgust.

As well as producing I am a qualified cognitive therapist who has worked with pros at the highest level and have encountered plenty of "Pampered Pets" as well as well rounded generous individuals so do not say that patronising and precious behaviour of the kind described is actually "rules of the profession"

In response to Why EQ when moving the microphone can do so much more?, Agustin Espina writes...

I totally agree to this point of view... I prefer to spend a whole session miking a good drum kit, tryng different mic positions, changing microphones to get some good tracks to work than to spend the same time in the mix trying to make a poor track sound as if it was recorded by Bob Clearmountain. That's the starting point... Some times a client wants you to mix a poorly recorded material and make it sound "great"... You need great tracking to have a great mix... If you don't have great tracks, all you'll have is a great sounding mess.


In response to The ultimate guide to PC backup and disaster prevention, Peter Mueller writes...

You asked some time ago

"Somewhere out there in RP-land there is someone who knows of a SIMPLE and FOOLPROOF method of backing up a Windows PC - data, operating system, applications, activations and all"

Here we go:

1. Forget about "Foolproof", please. If this is your most important issue: don't use computers at all! Data backup procedures consist of hardware, planning plus discipline.

2. What is "Simple"? Let's continue with "Simple and affordable for Peter".

3. Take some money and purchase a state of the art internal hard disk drive (Suitable to your pc hardware) plus some external USB drives. These units hide a naked hard disk which could easily be replaced.

4. Configure your pc to use one partition for system and another one for project (recording) purpose. Buy and install Acronis True Image, open your computer, insert one of the new hd drives to a spare port and clone your computer's harddisk partitions to the new device (afterwards it can be used 1:1 instead of the original without making any changes). Repeat this procedure after major changes of operating system version, installed application software or hardware. Don't reuse old drives - buy a new one. Keep the old hardware in a safe place (not in your studio) to have the opportunity of stepping back to a working environment immediately.

5. Rotate between different (= one per working day) usb drives for daily project data backup, and another four usb drives for weekly project data backup. Store these backup devices at a different location - not in your studio. Always proof data consistency of your latest weekly backup.

6. Store your finished projects on extra media. Don't forget to "refresh" CD-Roms after two years.

7. Use a firewall and a daily updated anti virus tool. An undiscovered virus will eat up your backup data in a period of four weeks (in the example above).

8. Don't allow external access to systems that are vital for your work.

p.s: This procedure seems to be quite difficult and costly. But it is not. The mere quantity of data needs appropriate hardware. This is an easy and safe way to avoid losses or overwriting of data.

In response to Warmth - what is it? How do you get it? Nostalgia - it isn’t what it used to be (1), Karel Mars writes...

I beg to differ on the subject of audio and vacuum tubes.

In my experience vacuum tubes excel in audio. I get a much more musical experience from my single ended 6L6 amplifier than any solid state amp I have heard.

I quote from "The Cool Sound of Tubes" article:

Briefly stated, a commercially viable number of people find that they prefer the sound produced by tubed equipment in three areas: musical-instrument (MI) amplifiers (mainly guitar amps), some processing devices used in recording studios, and a small but growing percentage of high-fidelity equipment at the high end of the audiophile market. These areas employ vacuum tubes of the type once known as receiving tubes, but now called simply tubes. Not only has the use of vacuum tubes in these fields defied the semiconductor tide elsewhere, but such use and demand has even surged in the course of the 1990s.

Today vacuum-thermionic devices hold sway over the US $100 million worldwide guitar amp business. One rough estimate shows a 10-percent-per-year growth in demand for tubes used in MI amplifiers and high-end audio since the late 1980s, with no apparent slackening—even during the U.S. recession of 1991-92.

In response to Behringer's Ultragain ADA8000 mic pre misses a trick, Josh Tays writes...

The ADA 8000's eight analog outputs from the ADAT in, are incredibly useful when running live sound from a digital console. You can do a number of monitor mixes, delay zones, etc right out of the console and if you are using good speakers and amps the parametric eq and the stock delays should be enough to tune all of those zones very respectably and inexpensively as well.

In response to The ancient myths and legends of soundproofing, Bernard Matthews writes...

Chicken egg boxes are known to be useless- use turkey egg boxes as they're bigger and absorb more frequencies. Bootiful

RP response: Or ostrich egg boxes to get down to even lower frequencies...

In response to Any acoustic space in your own recording studio, G writes...

Hi. Some of your articles are very interesting. I use IRL - a bit heavy on cpu 002R LE for most tasks though when running other plugins. WUP is a pain though. Most people i know are leaving waves in droves because of this extortion. If you buy a product - it should be yours forever - with files/ fixes etc up to the level/ version you paid. WUP is a sneaky and underhanded way to make people feel they have to buy the 'latest' versions etc. eg: If you invest $800 for Ren Max - then need to continue to pay $200 for a year or so - in 4 years it is almost the same as buying a new version. ( My opinion - I think I can guess theirs :) )

In response to Why multimike drums when the simple Glyn Johns four-mic technique gives great results? WITH INTERVIEW VIDEO!, Dan Lewis writes...

SURE DO wish you wouldn't encourage everybody to do thing the same way.

You claim greater 'naturalness'. Of course 'naturalness' sometimes is, sometimes isn't what we want. "million-seller" Lyon thinks this mic'ing technique is what has put him where he is?? Good engineers, good performances, good tunes got Lyon where he thinks he is. Prove me wrong.

RP response: We envy your negativity. It must keep you very warm at nights. Long nights... alone.

In response to Why did you change your DAW?, Jim Sarthou writes...

I'm an old "Pro" and started recording in the analog days (`70's). But when new technology began to creep in, I moved along with it - from ADATS to DAW and computers.

I've used Pro Tools, Samplitude, etc. but recently (2002) I discovered Sony Vegas, which I wanted to use for video editing. Vegas has a GREAT multitrack audio recorder/editor and is so easy to use that it let's you concentrate on your AUDIO craft - not the computer and fancy confusing interfaces like Nuendo, etc.

Why is Sony Vegas (now in version 8!) so unpopular and underrated?

I have my theories, but if I'm one of the lucky FEW who use Vegas, well, lucky ME...

In response to Could THIS be your next recording studio?, Frank Siler writes...

I would like to try for the prize in explaining the "old money" reference (I'm an American so I hope I qualify as a sufficiently separated colony). Formerly there were 240p to one Pound Sterling; however decimalization took place and now the Pound is 100p, just as there are 100 cents to Euros and American dollars. Cheers, Frank

RP response: Well done! The first correct response, and it only took seven weeks! We are often asked why prices for our e-books and videos are in US dollars when we are a UK site. Well that happened a couple of weeks after we started operating in 2000 when we kept getting asked, "What does this '£' thing means?". Roll on the Euro!

In response to Are you great, or just average? There's a fine line..., Richard Atkinson writes...

We must all remember that the music business is only a part of the entertainment business .

In response to A digital guitar - has the world gone mad?, Michael Sherwood writes...

Wow, I wonder at the cost of such and item? No doubt as any newly introduced technology has proven to be in the past, it is fairly expensive for your average Joe Friday!

Writing as a guitar player working in a midi-world these days, I am quite curious as to how the instrument interface creates the sound, whether by "note events" to drop into our favorite computer interface, or by Wav audio. I will be interested in discovering how versatile it really is.

In response to Are you great, or just average? There's a fine line..., Dez writes...

Good point David but there's a down side to the tribute band fame. Most of the 2nd division circuit has to use tribute bands to survive. The fact that these bands can pack out a venue and original bands can't sums up the live scene. Fans pay to see imitations of the real thing and yet when bands such as White Lion and Ratt come over from the USA they are lucky if it's half full. These are bands that have platinum album sales behind them. What hope for the young bands with everyone down loading for free and no gig nights available because they are booked up with tribute bands? Don't get me wrong I love the like's of Limehouse Lizzy who are keeping Phil's music alive but the reality is this, Many fantastic musicians are being starved of their creativity and are forced into cover bands are tribute acts just to play to an audience . We won't even get into the cartel that run most of the venues on the circuit that counts, you are either in the know or in the local pub, good luck guys you will need it!


RP response: You have a point. And I would much rather have seen a really good original act than the 'merely professional' act that supported the Counterfeit Stones.

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