Hi,
It does not use M/S as such. Stereo Width control was
implemented widely in portable gear without using M/S.
How ? Rather than contradict ...
It does as its a principle rather than an implementation.
Its reduction of width always for portable gear and the
two channels are bled together to reduce the S of M+S.
But may screw up the stereo image otherwise...
So does channel imbalance, you've no real point here ...
All the unnecessary extra circuit is something I personally do not like. High Quality Potentiometers worth using usually track very well, if using stepped controls for tone (which has much to recommend it) tracking si down to what tolerance resistors you buy.
Two sum and difference buffer/gain blocks on the input, two
at the output is the same as two buffer/gain stages IMO.
It seems we have very different goals. Mine is a maximum of sound quality both with and without tone controls, which in my personal experience precludes much added circuirt. Even adding an active Baxandal FUBAR's sound quality.
I'm not looking for an argument, just a discussion. The legendary
Leak Troughline tuner seemed not to be ruined by a tacked on very
basic transistor stereo demultiplexer. Some might argue, for the
sake of discussion, you could implement the sum channel using
valves, the difference channel using FETs, and the result would
be far nearer an all valve solution than all FET,.
Ciao T
Hi,
Aspects of the sum and difference approach appeal to me,
(especially as I've listened to the difference signal only),
but I can see it wouldn't appeal to most. Still, if you
want to do something different / plough your own
furrow, the idea / concept is there and it works.
rgds, sreten.
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Hi,
You are completely wrong. Portable equipment (Ghetto Blasters) always used width expansion and did not separate the signal to M/S at all. Maybe you want to first make sure you understand the topic.
I have used M/S (due to M/S Microphone) extensively under studio conditions, as well as normal 2-Channel recording. I personally favoured to convert to 2-Channel as early as possible. M/S has the potential for some interesting effects if desired, but I do not see any benefit from using it for tone control (or much else, TBH).
But by all means go for it.
Ciao T
You are completely wrong. Portable equipment (Ghetto Blasters) always used width expansion and did not separate the signal to M/S at all. Maybe you want to first make sure you understand the topic.
I have used M/S (due to M/S Microphone) extensively under studio conditions, as well as normal 2-Channel recording. I personally favoured to convert to 2-Channel as early as possible. M/S has the potential for some interesting effects if desired, but I do not see any benefit from using it for tone control (or much else, TBH).
But by all means go for it.
Ciao T
A method of mildly tweaking width would be a highly appreciated feature in a tone amp because even a really mild bit can assist perceived clarity and dynamics. This can help wake up some dull recordings.
Hi,
Not sure I'd agree. If L/R channels don't match you get image shift, if M/S do not match you get width shift. Neither one is desirable.
Ciao T
Not sure I'd agree. If L/R channels don't match you get image shift, if M/S do not match you get width shift. Neither one is desirable.
Ciao T
Hi,
I was thinking of the width systems in headphone systems , not really
thought about the "width enhancement" of ghetto basters, of course
that is going to be doing the near opposite, the "topic" was not defined.
You can argue a "width" control is wrong, but by the same argument so
would be "tone" controls. And what if the mastering used a "shuffler" ?
There are no absolutes when you are mastering, and IMO its hard
to try and apply "that will never be useful" to adjustment facilities.
rgds, sreten.
Hi,
But the real question is assuming your channels don't perfectly
match which is preferable ? Which one would sound better ...
I think its fairly obvious for mild channel mismatching ...
rgds, sreten.
This is very well said and describes my goal as well.
My current system provides a lot of enjoyment but there is the odd time when I think it would be fun to be able to tame records or CDs that are a bit hot because this was the preference of the mastering engineer at the time. Or to lift a little the bottom end that was attenuated to ensure the groves would fit on one side of the LP. Friends of mine who have tone controls on their tube receivers use them - and they sound good. A six band equalizer could grant more flexibility while sounding good - as the Palette showed.
So I encourage caution about adding requirements here. The more that is added, the more I fear that the resulting circuit will be a compromise. My preference remains to seek to design a very high end EQ circuit. Nothing more. Granted, this is all about entertainment and other means of adjusting sound to personal preference have their appeal too. Personally, however, my next step is EQ control.
Like Thorsten, I am skeptical of circuits with opamp ICs in them. In my opinion many are ok, but the best sound I have experienced has been from discrete solid state or tubes. At this time, there are no opamp ICs anywhere in the audio path of my system. I might consider using them for the bottom end, as long as it is not detrimental to the midrange and highs. But if I can continue to avoid them, I will.
Looking forward to returning to the idea of a ZenEQ, DIYable using components that can be purchased, traded, or custom made - perhaps through some group buy. I am thinking of the big inductors in particular, which may not be readily available in the exact values needed.
Pierre
Hi,
Actually, what you really need are "width-tilt" controls.
Usually, due to requirements of mono-compatibility and underlying limitations of recording techniques many recordings have a "too wide top" and "too narrow bottom", though the opposite is also found.
So ideally we have a control that does not change width much between around 300Hz and 3KHz, but can either widen or narrow both LF and HF.
This is not impossible to implement in an partially passive way without actually converting the signal to M/S.
Ciao T
Actually, what you really need are "width-tilt" controls.
Usually, due to requirements of mono-compatibility and underlying limitations of recording techniques many recordings have a "too wide top" and "too narrow bottom", though the opposite is also found.
So ideally we have a control that does not change width much between around 300Hz and 3KHz, but can either widen or narrow both LF and HF.
This is not impossible to implement in an partially passive way without actually converting the signal to M/S.
Ciao T
That's interesting. It is the conversion to/from M/S that scares me (sound wise). Maintaining good matching between summing and differential amps both pre and post the eq filters is not trivial and risks adding to the complexity. So this width adj feature can be added without an overhaul of the left and right path?
Hi,
Okay, let us propose the following:
1) My line stage with tone control from Post # 36 and 0.5dB channel difference for the tone controls with the controls set to maximum (so at moderate settings there will be less difference).
2) An A/B to M/S Matrix, with input buffers, followed by tone controls, followed by a M/S to A/B Matrix followed by the line stage, with 0.5dB channel difference for the tone controls with the controls set to maximum (so at moderate settings there will be less difference).
I agree - it is very obvious which would exhibit less impairment of sound quality.
Ciao T
Okay, let us propose the following:
1) My line stage with tone control from Post # 36 and 0.5dB channel difference for the tone controls with the controls set to maximum (so at moderate settings there will be less difference).
2) An A/B to M/S Matrix, with input buffers, followed by tone controls, followed by a M/S to A/B Matrix followed by the line stage, with 0.5dB channel difference for the tone controls with the controls set to maximum (so at moderate settings there will be less difference).
I agree - it is very obvious which would exhibit less impairment of sound quality.
Ciao T
Hi,
Yes. The classic "Width expansion"circuit usually just needs one (adjuatable?) resistor and one cap linked into the feedback loop, however for width expansion at low frequencies a choke would be needed. Reducing channel separation is also quite simple.
Ciao T
Yes. The classic "Width expansion"circuit usually just needs one (adjuatable?) resistor and one cap linked into the feedback loop, however for width expansion at low frequencies a choke would be needed. Reducing channel separation is also quite simple.
Ciao T
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Hi,
Sum and difference stages don't need addition input buffers or additional
line output stages. Quite frankly whilst I accept its an architecture unlikely
to be adopted, I'd appreciate not having to deal with nonsense arguements.
rgds, sreten.
Width Tilt could be extremely bad with headphones if when the the treble is widen enough for realism, then narrower bass is on top of your head.
However, separate treble-width and separate bass-width would be fantastic.
Hi,
The most minimal M/S Encoder & Decoder circuits require at least 2 Op-Amp's each. If we want to avoid genertaing too much noise the impedances of this matrix must be kept low. We may want a higher input impedance for a completed line preamplifier using a tone Control, so an input buffer is required. If we want gain for the line stage we need to add this gain before or after the linestage. We need additional Op-Amp's for the tone control.
At the absolute Minimum, for a functional line-stage using your approach I count:
Input Buffer 2 pcs Op-Amp
A/B to M/S encoder 2 pcs Op-Amp
Tone Control 2 pcs Op-Amp
M/S to A/B decoder 2 pcs Op-Amp
Gainstage 16db 2 pcs Op-Amp
Grand total 10 pcs Op-Amp
My suggestion in post 36 uses ONE Op-Amp per channel to offer 16dB linestage gain, tone control etc. It offers a complete full function preamp using two Op-Amp's. If desired even stereo width control can be added without requiring extra op-amps.
Any claimed advantages for the M/S based solution appear pure conjecture, without any evidence presented, as tone control imbalances in eitrher system lead to spatial shifts, which is more pernicious is far from from reliably determined.
Yes. So would I.
Ciao T
PS, I aware of Michael Gerzons paper, his point was however to deliberately use different EQ between Mid & Side channel as effect.
The most minimal M/S Encoder & Decoder circuits require at least 2 Op-Amp's each. If we want to avoid genertaing too much noise the impedances of this matrix must be kept low. We may want a higher input impedance for a completed line preamplifier using a tone Control, so an input buffer is required. If we want gain for the line stage we need to add this gain before or after the linestage. We need additional Op-Amp's for the tone control.
At the absolute Minimum, for a functional line-stage using your approach I count:
Input Buffer 2 pcs Op-Amp
A/B to M/S encoder 2 pcs Op-Amp
Tone Control 2 pcs Op-Amp
M/S to A/B decoder 2 pcs Op-Amp
Gainstage 16db 2 pcs Op-Amp
Grand total 10 pcs Op-Amp
My suggestion in post 36 uses ONE Op-Amp per channel to offer 16dB linestage gain, tone control etc. It offers a complete full function preamp using two Op-Amp's. If desired even stereo width control can be added without requiring extra op-amps.
Any claimed advantages for the M/S based solution appear pure conjecture, without any evidence presented, as tone control imbalances in eitrher system lead to spatial shifts, which is more pernicious is far from from reliably determined.
Yes. So would I.
Ciao T
PS, I aware of Michael Gerzons paper, his point was however to deliberately use different EQ between Mid & Side channel as effect.
Hi,
You must understand that headphone listening corrections for listening to recordings aimed at Speaker listening is a totally different domain as what I discuss. I do not generally concern myself with this at all, as there are virtually no recordings available that make any sense on headphones and the best available corrections are software based - I "remaster" music I put on my portable using that.
I am only concerned with "re-mastering" recordings that have, for a variety of reasons technical defects (too much bass, too much presence, mono bass and wide-angle stereo treble) and hence sound unnatural and objectionably so.
Headphone listening with recordings made and mastered for speaker listening is a whole other kettle of fish and trying to superimpose the needed spatial and frequency response corrections for that on top of recording flaw correction severely muddles the issues and leads to compromises that are rather less than desirable.
For many even the suggested controls on "Palette Clone" are going to be at the limit of tolerance of may. I think six controls with possibly adjustable centre frequency and a stereo width control selectable between "Tilt" and "Blend" is even the maximum that I would suggest, as it suffices to "repair" most recording problems that can be corrected.
I would suggest to apply any headphone specific corrections (crossfeed, free-field equalisation) where they belong, in the headphone amplifier section. Moreover, these are adjustments and controls that are listener/headphone specific and not recording specific, so they can use very simple/purist switchable circuitry.
Ciao T
You must understand that headphone listening corrections for listening to recordings aimed at Speaker listening is a totally different domain as what I discuss. I do not generally concern myself with this at all, as there are virtually no recordings available that make any sense on headphones and the best available corrections are software based - I "remaster" music I put on my portable using that.
I am only concerned with "re-mastering" recordings that have, for a variety of reasons technical defects (too much bass, too much presence, mono bass and wide-angle stereo treble) and hence sound unnatural and objectionably so.
Headphone listening with recordings made and mastered for speaker listening is a whole other kettle of fish and trying to superimpose the needed spatial and frequency response corrections for that on top of recording flaw correction severely muddles the issues and leads to compromises that are rather less than desirable.
For many even the suggested controls on "Palette Clone" are going to be at the limit of tolerance of may. I think six controls with possibly adjustable centre frequency and a stereo width control selectable between "Tilt" and "Blend" is even the maximum that I would suggest, as it suffices to "repair" most recording problems that can be corrected.
I would suggest to apply any headphone specific corrections (crossfeed, free-field equalisation) where they belong, in the headphone amplifier section. Moreover, these are adjustments and controls that are listener/headphone specific and not recording specific, so they can use very simple/purist switchable circuitry.
Ciao T
Folks,
Showing simple circuits that allow stereo width expansion and reduction are actually shown among other by Rod Elliott (sadly as usual with no attribution to the origin of these circuits, as is his habit) here:
Stereo Width Controllers
The simplest circuit is here:
It can easily be re-arranged to have the "blend" part in the input and "cancel crosstalk" in the feedback loop of the linestage I suggested in post # 36.
To get the discussed "tilt" the crosstalk cancellation signal must be lowpassed for LF width expansion and highpass for HF width expansion. A switchable RC can be used. The same principle of low, or high-passed adjustable crosstalk applies to the "blend" control. Level steps that make sense may be obtained from Michael Gerzon's Paper.
Ciao T
Showing simple circuits that allow stereo width expansion and reduction are actually shown among other by Rod Elliott (sadly as usual with no attribution to the origin of these circuits, as is his habit) here:
Stereo Width Controllers
The simplest circuit is here:
An externally hosted image should be here but it was not working when we last tested it.
It can easily be re-arranged to have the "blend" part in the input and "cancel crosstalk" in the feedback loop of the linestage I suggested in post # 36.
To get the discussed "tilt" the crosstalk cancellation signal must be lowpassed for LF width expansion and highpass for HF width expansion. A switchable RC can be used. The same principle of low, or high-passed adjustable crosstalk applies to the "blend" control. Level steps that make sense may be obtained from Michael Gerzon's Paper.
Ciao T
Thank you. This is much simpler than the M/S approach indeed. For width expansion only, one could do without the blend part and add a pot in the cross talk cancelation circuit. Clean and elegant.
As far as I can tell, though, the width expansion function requires a feedback loop or an active stage with differential inputs. Feedback and differential amplifiers are quite acceptable when done right. Yet I remain attracted by the daring german eq circuit which has zero feedback. It is so simple.
Pierre