I love tone controls, no really!

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I'm not trying to start an argument here but tone controls have got a lot of bad press for a long time. I don’t believe they are the devil reincarnate.

I use tone controls for two reasons;

Somebody who loves bass mastered some of my favourite recordings. Either that or the monitors were lacking in bottom end. Try Arron Neville’s “Warm Your Heart,” there are others. This is particularly a problem for me because my system is flat to 25Hz and if the recording isn’t you know’ll it.

Secondly, the loudness curve is generally accepted, (ISO standard 226). If I’m playing music below its natural level a bit of extra boom and zing never hurts. In fact it sounds more natural.

Having said that I switch in the controls less than 5% of the time, only when the need dictates.

The tone controls that I use are shunt controls and are easily disconnected, (via a switch) from the preamp. They can not degrade the sound when disconnected.

Your thoughts?
Regards WALKER
 
the APT preamp had nice tone controls

My current homebrew preamp doesn't have tone controls. However, my previous one did. I found them useful, but because it was a homebrew, there were some things I did to eliminate some of the negative issues surrounding their use.

I think most commercial products have too much range for their controls. I've seen some that advertise +/- 20dB! I think the limit should be +/6dB.

The turnover frequencies need to be chosen very carefully and the circuit topology needs to be one that minimizes interaction, doesn't introduce excessive noise, distortion, etc. I modeled my tone controls after the APT preamp from the 80's. The design was patented, but simple to analyze and change if one so desired. Worked quite well. Actually, the entire APT preamp was a nice design that was executed well for its day. I would be curious to see how well a modern execution of the design would perform. Quality of opamps and attention to design of power supply and grounding details have gotten much better since the APT was available. Doug Self's preamp designs use what I consider to be an improved form of the feedback volume control. This worked very well in my homebrew preamp also.

However, I think DSP tech is poised to rapidly take this analog domain function over to the digital domain, especially with the emphasis on surround sound these days.
So, it's a moot point :)

Michael
 
Walker,

I think that tone controls cannot degrade quality, if and *only if* properly designed, and *correctly* adapted to the others stages.

Very good results can be reached with Baxandall design, in old fashionned style : 12AU7 tubes, oil-paper condensers, and other good components, with cathode-follower stage at both inputs and outputs : 3 tubes for complete stereo unit. Cathode heaters must be powered with stablized dc current. The entire appliance must be shielded, and properly grounded.

In my opinion, it's more difficult (but not impossible) to reach as good results with transistorized designs, although slight changes in sound coherence, fluidity, are unavoidable.

Futhermore, I do agree with you : +/- 6 db at 100 and 10000 Hz are reasonnable values. But sometimes, buyers think that more efficiency is more quality...


Regards, P.Lacombe.
 
I totally agree with Walker....
Sometimes tone controls are necesseary.
I too have a lot of records and CDs with a tonal imbalance, which at times one wishes to correct. Sometimes it is rather astonishing that modern technology can be handled so ignorantly, particularly with a lot of the relaunches of e.g. classicial jazz, and other recordings, that are sent to market these days.
In addition, I also work with a community radio station, and frequently have to listen through recordings done under marginally conditions, in addition to the technological "abuse" that follows with rather untrained "reporters".

Somewhere along the line, this "no control" mania occurred. I can understand that, given some of the old fashioned and rather poorly constructed controls, but it is really only a matter of a high quality bypass switch.

Some 10 years ago, or so, I remember John Linsley Hood had some very interesting designs published, that combined with the best of modern op amps should do an excellent job. These designs had switchable freq's and were of the shelving type. But. -I would still go for the bypass switch......

[Edited by AuroraB on 12-03-2001 at 02:50 PM]
 
Parametric equalizers give you more control than standard tone controls and they can more accurately correct some problems. Unfortunately they often remove more detail than simple tone controls. As always you don't get something for nothing.

I use both but tend to use the parametric for PA use and tone controls at home. At home I always try to fix response problems at the source, but when the problem is in the recording what else can you do.

It's interesting that many fanatics (and I consider myself fairly fanatical) will use active equalisation and crossovers but refuse to consider tone controls.

Of course the best sound quality comes when you don't have to use either.
Regards WALKER
 
Hi Walker,

Actually a good parametric eq can be gentler on the sound than traditional (graphic) tone controls. One of the big advantages to a fully parametric eq is that you set the 'Q' (bandwidth) as well as the center frequency, which means that you can tailor the systems frequency response to deal precisely with problems. The best professional sound reinforment systems use parametric eq's (typically DSP based) to get the best sound out of their FOH speaker systems. The problem is that properly setting up a parametric eq takes more experiance (and test gear) than the usual 31 band graphic eq and it is visually less obvious what is being adjusted.

P.S. Ashley makes a 7 band parametric eq that is absolutely killer. Best value in an analog parametric I have ever seen.

Phil Ouellette
 
We all need tone controls

Every one should have the ability to make the most out of their system and fine-tune it to their environment and ears. My upcoming preamp project will have tone controls.

If you believe that the recording engineer adjusted the sound to be perfect when using his monitor speakers then of course you do not need tone controls. However if the tone control (equalization) settings at the time of recording were not perfect for your system then you may just need to do some re-equalization. Hence you would need tone controls.

There are significant amounts of equalization used when recording studios record. It is part of life. Along with equalizers there are lots of compressors, noise gates, reverbs and other equipment that modifies the properties of signal. Mostly all audiophile purists deem this equipment bad to use in the home environment but seldom appear to take into consideration their use in recording studios. The fact of the matter is of course is that much of this equipment is required to give us decent recordings when using most modern recording techniques.

Tone controls are thus a tool that can be used at times to improve sound quality at home just like it can in recording studios.

John Fassotte
Alaskan Audio
 
I've always been amused by this position that opamps/tone controls/multiple gain states/whatever are bad...so let's throw some more in.
Huh?
The logic escapes me.
If you've got a dirty window, the solution is not to smear <i>more</i> dirt on it. If it's the best view you're going to get of the outdoors, at least don't mess it up any more than it already is.
In the case of tone controls, people <i>assume</i> that they know what the tonal balance should be. With only rare exceptions, they weren't in on the recording sessions, and haven't a clue. Now, I'm not saying that all recording engineers are competent--many clearly aren't--but I've never been convinced that tone controls are the answer, at least in a high-end system. The phase shift alone is enough to put me off, not to mention all the other gunk you've got to put in the signal path. I'll leave it for the low and mid-fi systems out there.
(There...you knew someone would finally show up to give a counterpoint...)

Grey
 
Grey, your comment implying that using tone controls "assumes" you know what the correct tonal balance should be, should also apply to not using tone controls. Since none of us were in at the recording session, none of us know what the sound should be. Is it correct to presume that our speaker/room combo sounds so like the one in the studio that we have no need of any form of correction?. This seems unlikely to me. Furthermore, not all recordings sound pleasant when played at home. The question one is faced with is whether to doctor the playback to be pleasant to ones ear and hence enjoy the music, or reject the music because of some notion of what it should sound like that is sacrosanct. With studio recordings there is no reference of "closest approach to the original sound", since the "original" was that heard through the studio monitors after sometimes extensive processing. Obviously if the tone controls even in their flat position butcher the sound then they should not be used. But if after the controls are adjusted, the result is more enjoyable, isn't this a good thing? Even Mark Levinson designed a very high end preamp (under the Cello label) with extensive tone controls, with the philosophy that they could improve playback quality. Even the best speakers are tone controls in reality!!
I would agree that the goal of designing a system is neutrality so that it works with the widest range of recordings, but then I see no harm of individual adjustement away from this to compensate for non-neutral recordings. The argument then becomes one of what is an appropriate form of adjustement that will be capable of "correcting" such recordings.
Andrew
 
OK-- let's get the heat up...;-)

Most newer recordings are processed to a degree that I seriously doubt that even the sound engineer is able to recall the setting on the desk without his cue sheet or the CPU recall function on modern desks. It is all about "creating the sound stage". Fair enough- but this should also give us the clue that a lot of the modern recordings are unusable as "reference recordings" for determining fidelity,- who of us knows how it was all intended to be ???
For a great number of years, it's been quite astonishing to witness the heat generated over minimalistic reproduction of recordings that have been passed though bucketloads of 741 op-amps.....
Personally, I try to use recordings with woodwinds, as these has been my own instruments for 40 years. But on the other side,-if you don't hear the difference between Benny Goodman and Artie Shaw- why bother with the equipment...???

As an "electroniciot" by profession, I most sincerely beleive in the "no frills" idea, but sometimes you have to--
When I have to, I would love to have the parametric section of my old Soundcraft desk, - but at home I will do with simpler controls, - and a gold plated switch to get rid of them when I don't need them.
 
Andrew,
I note that Cello didn't exactly take the consumer high-end market by storm, either, and Mark Levinson himself has moved on to Red Rose (tubes of all things--I never expected him to be in the tube end of things).
Your comment that speakers are tone controls is correct--but the objective is to design speakers that do as little 'tone controlling' as possible...yes? So why then turn around and destroy all the work that went into making as neutral a system as possible?
It strikes me that attempting to use tone controls to make one room sound like another is doomed to failure. There's a lot more to the differences between rooms than tone controls can even begin to approach.
Besides, how do you <i>know</i> that the sound that comes off the album isn't what the artist intended? I've heard a number of people live who sounded just awful in my opinion (in this case, I'm speaking of amplified music), but they said,"Oh no...there's nothing wrong. That's the way we want to sound." Philosophically speaking, to the extent that the medium is part of the message, if you tinker with the tone, you're changing their message.
Once you reach the "if it makes me happy..." argument, there's nothing else to be said. You've left the realm of reproduction and entered the realm of production, in the sense that you have decided to become an active participant in the recording process. That's okay, as far as it goes, but it's no longer hi-fi, per se.
(Somebody's got to play the bad guy around here--might as well be me.)

Grey
 
Hi Grey,

The way I see it, the main use for equalization is to make the speaker as natural as possible in your listening space. You can have a ruler flat amp and speaker system in a test chamber, but the minute you install it in a real room, the frequency response is going to go all over the place. What is wrong with trying to undo some of this unwanted coloration by using tone controls? The only other way to do this is to make sure the direct sound from the speakers overpowers any reflected sound which can only be done by restricting yourself to a much smaller sweet spot. I like the sound to be as listenable as possible throughout the room (I have friends and family that like to listen too) so am willing to accept a slightly less perfect sound experiance in the "best seat" in order to give everyone else a better sound.

I can also see the value in using "tone" controls to adjust a recording to sound better on your system. When a recording engineer mixes a song, he normally has a specific market and sound environment in mind (like car stereo's or boom boxes for example). A mix that sounds great (as least as great as is possible on this kind gear) on it's intended playback system often sounds horrid on more accurate systems. I have run into this same problem with PC sound. I recently upgraded my PC's speaker system and found that many games are mixed for typical cheap PC speakers (no bass) and when you play them through decent speakers the bass is way out of balance with the higher frequencies.

Phil Ouellette
 
I think the bad guy is Walker for having started this topic!!
Cello's business success or lack of it isn't an argument to say that tone controls are bad, indeed the tone control preamp received admirable reviews even from people who were traditional straight wire with gain guys. And to provoke yet more argument, isn't a tube amp one big tone control!!
Having designed many successful speakers through the years i would agree that the goal (or at least mine)is as nuetral as possible. However, this is not as easy as it seems, particularly at low price points. Moreover not everyone shares this viewpoint, as is obvious once you begin measuring different manufacturers offerings. Some definitely go for a "house sound".
I certainly wasn't implying that tone controls would correct the room response, I simply linked the two (speaker response and room response) in that they both modify the sound that the recording engineer hears, in a way that the consumer cannot know. Therefore it is unlikely that the consumer hears from the recording what the engineer intended. Although we cannot compensate for the room with tone controls, it has been shown that the sound in the mid to high range is not so effected by the room and is truly a property of the speaker, and some aspects of this may be correctable with the appropriate tone controls.
With regard to the reproduction/production argument, only a tiny minority of recordings make any pretention to capturing a "live" sound that one could hear if one were in the room at the recording session. So while it is indeed laudable to engineer the playback equipment to reproduce this as accurately as possible, and I will qualify myself by saying that this is generally my aim in design, this leaves an awful lot of recordings whose quality is then suspect. Hi-Fi is not just about the equipment, its about the recording as well. In fact it's much easier to get a satisfactory or impressive sound using a good recording with modest playback equipment than the other way around. I speak from many years of experience of running demos at shows !!!This leads to the old chestnut about the hi fi geek only listening to "audiophile recordings" of sometimes questionable musical value, (but boy do they sound good)while everyone else is enjoying the remaining vast legacy of recorded music. In the real world this is the main customer. The multi thousand dollar/pound audiophile systems are fun to design and they feed the engineering soul, but they certainly don't pay the rent !
As an amusing asside, your comment "if it makes me happy...there's nothing more to be said" reminds me of an argument I had with a philosophy student (I was a physicist).The "discussion" was building nicely until I questioned one statement. The answer was "you cannot argue against that, it's a self-evident axiom !". End of argument as far as he was concerned. Pity it wasn't self evident to me.
Andrew
 
Phil,
The problem with tone controls is that they control more than the tone. There are severe phase shifts involved, not to mention the added circuitry. Kinda makes a hash of having a time-aligned speaker when you drop in 20 degrees of phase shift via the tone control.
Andrew,
I agree--let's lynch Walker!
I dabbled in philosophy in school before coming to the crashing realization that not once in the entire history of the subject have they solved anything. They're still arguing about the same things today that they were 4000 years ago.
(Kinda reminds you of tubes vs. solid state...)

Grey
 
Grey, even the best time aligned speaker does not have linear phase response over the whole frequency range, due to the bandwidth restricted nature of all practical speakers. The phase response is governed by the frequency response. Modify one, or indeed improve one, and you automatically improve the other. So, if the speaker has a falling HF response, and therefore a change in associated phase shift, then correcting this frequency response with a lift from the tone control will improve the overall phase response. However, there are very very few time aligned speakers available in the market place, and those that purport to be so only achieve this on one narrowly defined listening axis. The off axis responses and all the reflections are not time aligned. The majority of speakers have phase responses with way more phase shift than that introduced by a tone control. The audible effects of a non flat frequency response are considerably more audible than those introduced by a modest and gradual change in phase.
Andrew
 
Sound Reproduction or Production

I do not think that Walker should be lynched!! Or Grey!!

I find these threads extremely interesting and sometimes humorous. Especially when you get down to the debate of music reproduction vs. production.

I find the whole concept of Hi-Fi audio a major paradox and somehow a bit of a joke, as someone who was a singer for many years and played several instruments as well and having come from a very musical family. My brother is a trumpet and French horn player as well the pianist. My mother has played the organ, harpsichord, accordion and piano for years. There are guitar, violin, cello, harmonica, and banjo players in my family as well. Yes, I know that this sounds a bit like I giving you a family talent display, but I simply providing a background for my outlook on audio and music, yes they are very different. Since moving to Sydney, Australia, I have been taking in a live concert or music event at least once a week , sometimes twice a week. My music experience runs from the gamut from a Capella vocals to rock and R&B.

What amuses me is that in our attempt to reproduce music, we seem to forget that as Grey has mentioned that very few live concerts are really live, meaning unamplified or mixed. So even in a "live" concert setting many times what we are hearing is a female vocal already modified by mic pickups, mixing boards and more. So are we even sure what a true female vocal sounds like? I can attest to the spine-tingling experience of standing beside a soprano and hearing her floating from note to note at the top of the musical scale, pure and unadulterated from any amplification in a rehearsal session. After over 5 years of being a lead baritone singer in a large classical choir, I can tell you that there is no sound system made today that will give you the thrill of over 100 voices in controlled tension through a quiet passage suddenly exploding into a powerful crescendo. I have yet to find a speaker that is capable of reproducing the power and presence of a kettle drummer gone mad after hours of submissive playing and allowed to rock the whole hall with the force of a musical climax that shakes the entire building and makes your chest vibrate like a bowl of Jello. But the truest test of any sound system is a piano solo, which covers most of the audible sound spectrum. I am fortunate to have a 8 foot grand piano in my great room to allow direct comparison. The real thing will leave any sound system for dead, regardless of cost or style, every time.

So what is music to me? It is not the sterile dissection of frequencies and time phases, but rather an emotional experience that involves all the senses and carries you to another world far from the everyday hum-drum of life. It includes the thrill of symphonies engulfing you with their power and presence and leaving you breathless and awe-struck. The intimacy of a smoky corner café where a small jazz quartet talks to you about the many moods and experiences of life in their own unique way. There is the spirit-lifting piano solos in the Sydney Opera House where each note comes flittering up you and wraps itself around you like a long lost lover. The throbbing beat of local gigs playing at the clubs, that takes control of your body and makes you dance until you are exhausted. The startling presence of a stringed quartet busking on a busy street corner playing the Canon and as you listen you are suddenly unaware of the roaring buses and noisy pedestrians as you are lifted above the hustle and bustle of daily life. So when I hear of people listening in total darkness to eliminate noise, I have to chuckle because I really wonder what it would be like to attend a Celine Dion concert with the lights out or to find myself engrossed by Handel’s Messiah at the Meyerhoff Hall in Baltimore when suddenly there is total darkness. I have yet to have a live musical experience in the dark, yes, there are many times I have leaned back in the box, closed my eyes, letting the music rush over me like a soul refreshing waterfall, but there is still the closeness of my wife next me and the aura of a small portion of humanity being whisked away together into a space and time far from the life that we face each day.

So I agree with Grey, if you have a dirty window, you don’t want to smear more dirt on it, but you also need to understand that you will never be able clean the window well enough to able to experience the view as if you went out on the porch, because you will not be able feel the breeze on your skin, hear the sounds of a late summer's evening, or smell the freshness of a spring day, as long as you are the wrong side of the glass. So while I admire the theory and engineering that is invested in the “High-End” sound systems, I simply can not justify an investment into hardware that leaves me feeling empty and emotionally unattached. I can appreciate the "wire with gain" theory, but it all starts to fade into the distance when you come back from a evening at the Australian Chamber Orchestra. I am more than gracious enough to allow each person to define their own definition of music. My only challenge to everyone is, do you have enough experience in the original to be able to identify the reproduction and realize that the reproduction will never equal the orignal. And that applies to everything in life, antique furniture, fine artwork, classic cars, Swiss watches, and true love.

Given $10,000 to spend on music, I would surely make an upgrade on my existing speakers as they have seen their better days and I would make a major expansion to my collection of titles, but both would be tempered by my desire enjoy the original rather than the reproduction. How many audiophiles have a $10,000 system to play $2,000 worth of music!

So Walker, you can relax, I have just went to the top of the lynching list. So till the Klan gets here to take me away, I will pull out about five old vinyls of jazz and put them on my old Technics stack turntable, fire up my ancient Harmon Kardon amp and play some music from my equally aging Boston Acoustics. It may brutally twist and distort the signal, but when I hit my favourite listening chair and the music starts to flow, it will take me to place where I remember why I must make sure I get down to the nearest music hall as soon as possible to get my next high.

Remember above all, whatever music theology you ascribe to, and whatever your sound system, that music is like love, you can’t live with it, you can’t live without it, and only the real thing satisfies.

Don’t let the music stop,

Sun, Surf & Sound
 
Dear all, if only, I could go out to the porch more often. I am envious of those how can, my excuse, WKM, (wife kids mortgage), that’s ok though, it'll change soon.

Who started this analogy, that's right, Grey, now I know that you could have come up with a better one. Analogies are never accurate, they are a popular and at times powerful tool to help sway opinion but never accurate. Just for fun lets stick with it a little longer.

Back to the dirty window, ever noticed that some times it isn't that dirty sometimes it has a blue tinge. A little filtering removes and the cast and I admit adds some extra distortion. Take the filter off and replace it with a cleaner one, a bit better, why doesn't any make a perfect filter. Anyhow now I have the option, at the flip of a switch I can add or remove it I have a choice. Sometimes it's better with the filter, not often, but sometimes.

My Grandmother was an artist and I have a painting of hers that really moves me, some times I like to sit back and admire it. If the lighting is poor I turn on illumination. The illumination adds a yellow tinge but I can see it better and after a while I don't notice the cast and the painting still moves me. I can accept that some may prefer to squint in the dark and that’s their option. I'm trying to produce an analogy of listening to music below its natural level. Grey, you're not the only one who can produce lame parallels. Which makes me think or the most common from of distortion that I encounter, volume distortion, but that’s another thread.

I don't really like filters and I wish that the poor recordings were better. I do like filters when they can repair or reduce the damage done. I suppose I like options and have seen many systems were this option does not exist. Just don’t think that if you are found with tone controls that your not an Audiophile, (if that’s what you like being called).

For me it's not about the bass, it's never been. It's not about the equipment, nor is it about the music. It's about the passion, and that’s the problem with ABX, (but that’s yet another thread).

Regards WALKER

PS What's the definition of an AUDIOPHILE? Someone who needs to get out more often?
 
Window washer

I continue to support the use of tone controls to solve specific problems.

Take the dirty window that Grey mentioned. From my view point the dirty window is equal to a poor recording in need of help. You clean the window with electronic tools such as tone controls or equalizers.

These items are not to be feared. They can do wonders if used properly when needed. If and when they are needed is a matter of personnel taste and circumstances.

John Fassotte
Alaskan Audio

[Edited by alaskanaudio on 12-05-2001 at 02:04 PM]
 
Sometime over the next day or so, I will find my schematic of the APT tone control that I mentioned earlier and post it (or a link). Those that like tone controls and are curious may want to check it out and maybe play with simulations to compare it to the straight baxandall circuit.

If anybody can tell me how I can include a small gif in this box, send me mail :)

Stay tuned ....

Michael
 
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