Hi,
You could post a direct link to your circuit.
http://ianamillar.com/blog/wp-content/uploads/Loudness-Circuit.gif
http://ianamillar.com/blog/wp-content/uploads/LoudnessEstimates.jpg
It is very similar to the one found in McIntosh gear. It works quite okay, but it has a major drawback. There is no direct link to SPL, so you need to set this control by guesswork.
I would propose that it is preferable to integrate the physiolgical correction and volume control into one circuit and to add a separate gain control that allows the system gain.
My homegrown 1980's control centre had input gain controls (and a set of VU Meters to set them right - VU Meters read average loudness) and several selectable outputs with output gain controls to drive different Amplifier/Speaker systems.
The Volume control was based on the original circuit of the physiologically equalised Eckmiller fader, but implemented with a 40 Position rotary switch...
Output gain was set with the volume control at "0dB" (it went to +14dB IIRC) and an SPL of 85dB with pink noise. Input gain controls where set for peaks to 0dB VU with music program and needed adjustment for example between different Radio Stations.
An example of a studio level control with physiological equalisation can be seen in the Neumann W482ST which can be found here:
Vintage german modules (Neumann, Siemens, TAB, IRT, Lawo, ANT, Eckmiller, Adis, Monitora and Telefunken modules and Braunbuch scans)
The levels and EQ as set on the W482ST are shown here:
The Neumann W482ST was still produced in the mid 90's and used by the publicly funded Radio & TV in Germany...
Ciao T
You could post a direct link to your circuit.
http://ianamillar.com/blog/wp-content/uploads/Loudness-Circuit.gif
http://ianamillar.com/blog/wp-content/uploads/LoudnessEstimates.jpg
It is very similar to the one found in McIntosh gear. It works quite okay, but it has a major drawback. There is no direct link to SPL, so you need to set this control by guesswork.
I would propose that it is preferable to integrate the physiolgical correction and volume control into one circuit and to add a separate gain control that allows the system gain.
My homegrown 1980's control centre had input gain controls (and a set of VU Meters to set them right - VU Meters read average loudness) and several selectable outputs with output gain controls to drive different Amplifier/Speaker systems.
The Volume control was based on the original circuit of the physiologically equalised Eckmiller fader, but implemented with a 40 Position rotary switch...
Output gain was set with the volume control at "0dB" (it went to +14dB IIRC) and an SPL of 85dB with pink noise. Input gain controls where set for peaks to 0dB VU with music program and needed adjustment for example between different Radio Stations.
An example of a studio level control with physiological equalisation can be seen in the Neumann W482ST which can be found here:
Vintage german modules (Neumann, Siemens, TAB, IRT, Lawo, ANT, Eckmiller, Adis, Monitora and Telefunken modules and Braunbuch scans)
The levels and EQ as set on the W482ST are shown here:
The Neumann W482ST was still produced in the mid 90's and used by the publicly funded Radio & TV in Germany...
Ciao T
Comments
You might want to review this thread also:
http://www.diyaudio.com/forums/analog-line-level/186190-cello-audio-palette.html
I and others had the opportunity to put in a LOT of "listning time" with an offshoot of the Palette Preamp and offer the following suggestions.
If you are going to attempt any type of "tone" control, I'd suggest the Program Equalizer approach. Break the audio band up into segments, and construct low Q, adjustable filters that can apply a boost or cut to them. The frequencies Berwin/Cello chose work well - 20hz or thereabouts for deep bass; 120 or so for lower midrange upper bass and then one or more filters in the 500hz to 3 or 5Khz range - finally "something" around 15 to 20khz. The midrange is tricky, in that I find I use the filters there more in a "subtractive mode" - lowering vocal and instrumental "glare", and versitility there helps. One design I use actually has 5 switchable center points - 500 and 850 then 1/2/3K. Regarding deep bass - it's either there or not - if it's there, you may want to add a bit more but probably not - if it's not there to begin with, not amount of boost can "bring it back". 20K is interesting - want a real kick try 50K!
Next is the abount of boost or cut. I'm finding that +/- 4dB or so is all that is needed between 500 - 5000. Maybe +/- 8 at 120 and 10K and maybe +/- 12 at the extreems. The Palette allowed for more but I've found that I never turned up the controls anywhere near the ends.
The conceptual design is actually most similar to that shown in the old National Audio Handbook with paralleled op amp filter sections, preceeded (and followed) by a low impedance driver. The new National chips seem to be ideal and even though there are a lot of them in each channel, their "presence" is virtually inaudible.
Finally - ease of use is paramount. Put the filter circuitry in as small a box as possible, and connect it to the rest of the system via a long umbilical so you can operate it right from your operating position - include a defeat switch and gain trim for both channels. No it's really useful
Charles
You might want to review this thread also:
http://www.diyaudio.com/forums/analog-line-level/186190-cello-audio-palette.html
I and others had the opportunity to put in a LOT of "listning time" with an offshoot of the Palette Preamp and offer the following suggestions.
If you are going to attempt any type of "tone" control, I'd suggest the Program Equalizer approach. Break the audio band up into segments, and construct low Q, adjustable filters that can apply a boost or cut to them. The frequencies Berwin/Cello chose work well - 20hz or thereabouts for deep bass; 120 or so for lower midrange upper bass and then one or more filters in the 500hz to 3 or 5Khz range - finally "something" around 15 to 20khz. The midrange is tricky, in that I find I use the filters there more in a "subtractive mode" - lowering vocal and instrumental "glare", and versitility there helps. One design I use actually has 5 switchable center points - 500 and 850 then 1/2/3K. Regarding deep bass - it's either there or not - if it's there, you may want to add a bit more but probably not - if it's not there to begin with, not amount of boost can "bring it back". 20K is interesting - want a real kick try 50K!
Next is the abount of boost or cut. I'm finding that +/- 4dB or so is all that is needed between 500 - 5000. Maybe +/- 8 at 120 and 10K and maybe +/- 12 at the extreems. The Palette allowed for more but I've found that I never turned up the controls anywhere near the ends.
The conceptual design is actually most similar to that shown in the old National Audio Handbook with paralleled op amp filter sections, preceeded (and followed) by a low impedance driver. The new National chips seem to be ideal and even though there are a lot of them in each channel, their "presence" is virtually inaudible.
Finally - ease of use is paramount. Put the filter circuitry in as small a box as possible, and connect it to the rest of the system via a long umbilical so you can operate it right from your operating position - include a defeat switch and gain trim for both channels. No it's really useful
Charles
Maybe the rather successful OP275 on regs, for input buffer? Something like: Bass, Drum, L.Voice, H.Voice, Rasp, Air in six dials, although similar to triple tilt? So, what does the schematic for it look like?
P.S.
Thought up something kind of funny but useful--Paralleled JRC4560L's Output can really drive headphones, which would be useful for both test and as a beneficial function. Well, 4560's run parallel can help with rich clear baritone and rather amazing bass, and successfully drive a very wide variety of loads, such as 16R to 100k range, so I thought this was at least worth a mention.
Hi,
If you look above at post # 22 this is discussed, as far as circuits go. It is in principle the same as the 3-way Tone Control, but with 4 Mid-band controls and suitably scaled resistors and capacitors. Calculation formulas are in the original article at headwize linked in. Using Tina-Ti makes designing the EQ quite easy, calculate roughly, then fine-tune in the sim...
As for the control ranges, the frequencies of the original Cello Palette EQ correspond well with what you list. Drums for example centre around 120Hz (lower Toms, upper range kick-drum), the lower voice range is around 500Hz, rasp is at 4-6KHz and "Air" is at the very high top-end and so on...
This would not necessary be my choice, but the principle will work with these as well, you can even use NE5532 if you must.
Ciao T
If you look above at post # 22 this is discussed, as far as circuits go. It is in principle the same as the 3-way Tone Control, but with 4 Mid-band controls and suitably scaled resistors and capacitors. Calculation formulas are in the original article at headwize linked in. Using Tina-Ti makes designing the EQ quite easy, calculate roughly, then fine-tune in the sim...
As for the control ranges, the frequencies of the original Cello Palette EQ correspond well with what you list. Drums for example centre around 120Hz (lower Toms, upper range kick-drum), the lower voice range is around 500Hz, rasp is at 4-6KHz and "Air" is at the very high top-end and so on...
This would not necessary be my choice, but the principle will work with these as well, you can even use NE5532 if you must.
Ciao T
As for the "interesting Jfet input" whatever you find suited is fine by me, but I need availability of a 10k input. Of course a preamp may have more than one input. My guess of OP275 is because, although terribly difficult to solder the tiny things, it can drive hard without that hard sound problem that tone controls can't fix. A discrete buffer would be okay if the parts are carried by Mouser, Digikey, RS, etc. . . so that it can be done.
As for the op-amp that actually does the tone amp work, whatever you like is fine. I'd hope for something currently produced that you'd actually like to use. That would narrow down the selection considerably, wouldn't it?
I mentioned the parallel 4560's to power the headphone jack, not the RCA jacks. For a couple of dimes, it is really wonderful to have the option of a high current output. Headphones and some power amplifiers, need a shove. And, likewise, a parallel 4560 can drive hard without hard sound (that is the output of M-Audio Revo 5.1). Whatever drives it, I would consider a headphone jack vital for a preamp. A preamp can have more than one output.
Other desires include regulated power (or at least capmulti) and adjustable gain (or at least enough gain for a computer set to ~60%).
As for Tina Ti, well, I have been trying and have discovered endless opportunities to make it restart the computer but not one bit of useful output. The means to build the tone amp is unclear and may be as absent as the schematic. I'm sorry, but I just don't have the skills to make such an involved schematic.
Hi,
OPA1641 was found by Joachim Gerhard (not me) and looks with an external buffer.
These days over-complicated buffer circuits with as many parts as can be fitted seem to be all the range, me? I'd use an IRF610 (or a BJT if the Op-Amp has a build in emitter follower output) and an LM317 set as CCS. With around 200mA quiescent current you get around 3.3 Ohm open loop output impedance and can drive 4V continous into a 32 Ohm pair of can's.
Doesn't narrow things down much, we have lots of options.
My own pre will have just Bass/Treble and Loudness and use a discrete OPA running on +/- 60V using plenty of "unobtanium" parts (I have standards to keep), but if you want to work on an easy "palette style preamp" I'll help as much as I can.
What computer and OS are you using? It runs excellent here...
Ciao T
OPA1641 was found by Joachim Gerhard (not me) and looks with an external buffer.
These days over-complicated buffer circuits with as many parts as can be fitted seem to be all the range, me? I'd use an IRF610 (or a BJT if the Op-Amp has a build in emitter follower output) and an LM317 set as CCS. With around 200mA quiescent current you get around 3.3 Ohm open loop output impedance and can drive 4V continous into a 32 Ohm pair of can's.
Doesn't narrow things down much, we have lots of options.
My own pre will have just Bass/Treble and Loudness and use a discrete OPA running on +/- 60V using plenty of "unobtanium" parts (I have standards to keep), but if you want to work on an easy "palette style preamp" I'll help as much as I can.
What computer and OS are you using? It runs excellent here...
Ciao T
Hi,
It would not be an exact clone. The original Palette uses paralleled active filters with discrete Opa's (if I am right they look a little like the JC-2 linestage), a very large number of them.
The original palette also uses these gorgeous 60 or so position switches for the Controls, these are next to impossible to replace.
The "lower range" Palette Preamp used normal pots and chip Op-Amp's, tons of them. Detailed schematics are not available in public domain.
So direct clones are not on.
What can be done are functional clones, that is an EQ with six rotary controls that has similar slopes and boost/cut ranges, with or without included preamp options.
For this we need to decide if we want a "High End" version (rotary switches, discrete circuitry, maybe valves) or a "Budget" version (pots and IC Op-Amp), or something that is not so much a concrete project but more just principle designs.
The cost of six Elma or similar switches is not small, but reasonable. Using these we get 11 cut and 11 boost positions.
We could use 2dB steps for Lowest and Highest Frequencies, 1dB for the intermediate bands and 0.5dB for the midrange bands. These kind of steps do make sense, together with the frequencies.
The cost of six high grade stereo potentiometers is not small either, but we get continuously adjustable adjustment.
Just for reasons of extremism, we could even make the whole network wholly passive, around 24dB attenuation, "massive-passive" style and leave the selection of the output Amp that will produce 24dB of low noise gain to the user, to taste. Could be a NE5532, discrete, even tubes.
I can help a little with a single such project, but I'm a bit short of time, so others would have to chip in on the electronic design legwork.
Ciao T
It would not be an exact clone. The original Palette uses paralleled active filters with discrete Opa's (if I am right they look a little like the JC-2 linestage), a very large number of them.
The original palette also uses these gorgeous 60 or so position switches for the Controls, these are next to impossible to replace.
The "lower range" Palette Preamp used normal pots and chip Op-Amp's, tons of them. Detailed schematics are not available in public domain.
So direct clones are not on.
What can be done are functional clones, that is an EQ with six rotary controls that has similar slopes and boost/cut ranges, with or without included preamp options.
For this we need to decide if we want a "High End" version (rotary switches, discrete circuitry, maybe valves) or a "Budget" version (pots and IC Op-Amp), or something that is not so much a concrete project but more just principle designs.
The cost of six Elma or similar switches is not small, but reasonable. Using these we get 11 cut and 11 boost positions.
We could use 2dB steps for Lowest and Highest Frequencies, 1dB for the intermediate bands and 0.5dB for the midrange bands. These kind of steps do make sense, together with the frequencies.
The cost of six high grade stereo potentiometers is not small either, but we get continuously adjustable adjustment.
Just for reasons of extremism, we could even make the whole network wholly passive, around 24dB attenuation, "massive-passive" style and leave the selection of the output Amp that will produce 24dB of low noise gain to the user, to taste. Could be a NE5532, discrete, even tubes.
I can help a little with a single such project, but I'm a bit short of time, so others would have to chip in on the electronic design legwork.
Ciao T
I bought the total program, computer and Bobcat package from Levinson with great regret - the WMP restricted the quality, the Dac was a disaster but surprise, the computer is still functioning - after all of it was returned to NY for repair!
Some later discussion with D Burwen elicited the "WMP is perfectly satisfactory for computer audio reproduction" statement - perhaps these days the program, WMP, etc is better - I doubt it!
I do find this pre-design for a good quality tone control centre very attractive indeed, particularly the possible addition of a "tilt" facility, o/p valve buffer, etc and I would like to assist in any way possible - a bit limited in technical design, flexible & persistant with pcb layout, but maybe useful in other more mundane ways .......
Some later discussion with D Burwen elicited the "WMP is perfectly satisfactory for computer audio reproduction" statement - perhaps these days the program, WMP, etc is better - I doubt it!
I do find this pre-design for a good quality tone control centre very attractive indeed, particularly the possible addition of a "tilt" facility, o/p valve buffer, etc and I would like to assist in any way possible - a bit limited in technical design, flexible & persistant with pcb layout, but maybe useful in other more mundane ways .......
Hi,
No, WMP is as revolting as ever.
For such a system you could get any of the nice readily available pro-audio EQ plugins which will work with a range of really good playback software. My problem is the physical interface which is just not very good.
I'd want a control surface that I can call up using one button on my MCE remote and that is easy to use with only the MCE Remote cursor buttons for the EQ. Six or seven bands is perfect, definitly no more than that. Volume control should be integrated using Physiological EQ (optional) and gain adjustment (replay-gain?) for recordings with low average level so the rest of the system gets an "optimum gain" analogue setting
Underneath I'd like a room EQ engine included and the ability to tune each bands Frequency and adjustment range, plus LF and HF cutoff filters so that we can protect speakers/amp's.
The DSP Part should be a VST plugin.
Usability should be very good using touchscreen or remote.
The technical design mainly needs time to do the simulations to "curve-fit" the individual bands against the curves from Stereophile.
If we can everyone interested on board and to give us input we can get going.
My personal take would a passive James/Baxandall control using 10K Log Pots (easy to get) with resistors on switches optional. It will need a input buffer that can drive reasonably low impedances, however this can use any number of circuits that people like, no limits on technology.
We could include footprints for Op-Amp with BJT/Fet Buffer for the input and re-gain Amp on board and have optional "unbuffered" in's and outs for use with external circuits.
The issue is that the passive tonestack plus low noise "re-gain" amplifier limits our output noise to around -100dBU (unweighted) if I calculate right, we would need to run this through Tina or another sim to be sure. If we place the Volume Control after the EQ section the noise should be less of an issue, but that can get us into trouble with overload margins on the input.
If we go for an active EQ we can lower noise a bit more, if we go to 1K pots, like D. Self in his article we could get similar noise levels (-113dBU) as he has. The problem is that active circuitry limits our degrees of design freedom as we now need to design the Op-Amp's into the circuit, tubes are pretty much out.
Ciao T
No, WMP is as revolting as ever.
For such a system you could get any of the nice readily available pro-audio EQ plugins which will work with a range of really good playback software. My problem is the physical interface which is just not very good.
I'd want a control surface that I can call up using one button on my MCE remote and that is easy to use with only the MCE Remote cursor buttons for the EQ. Six or seven bands is perfect, definitly no more than that. Volume control should be integrated using Physiological EQ (optional) and gain adjustment (replay-gain?) for recordings with low average level so the rest of the system gets an "optimum gain" analogue setting
Underneath I'd like a room EQ engine included and the ability to tune each bands Frequency and adjustment range, plus LF and HF cutoff filters so that we can protect speakers/amp's.
The DSP Part should be a VST plugin.
Usability should be very good using touchscreen or remote.
The technical design mainly needs time to do the simulations to "curve-fit" the individual bands against the curves from Stereophile.
If we can everyone interested on board and to give us input we can get going.
My personal take would a passive James/Baxandall control using 10K Log Pots (easy to get) with resistors on switches optional. It will need a input buffer that can drive reasonably low impedances, however this can use any number of circuits that people like, no limits on technology.
We could include footprints for Op-Amp with BJT/Fet Buffer for the input and re-gain Amp on board and have optional "unbuffered" in's and outs for use with external circuits.
The issue is that the passive tonestack plus low noise "re-gain" amplifier limits our output noise to around -100dBU (unweighted) if I calculate right, we would need to run this through Tina or another sim to be sure. If we place the Volume Control after the EQ section the noise should be less of an issue, but that can get us into trouble with overload margins on the input.
If we go for an active EQ we can lower noise a bit more, if we go to 1K pots, like D. Self in his article we could get similar noise levels (-113dBU) as he has. The problem is that active circuitry limits our degrees of design freedom as we now need to design the Op-Amp's into the circuit, tubes are pretty much out.
Ciao T
Thanks Thorsten, for the info on the precision resistors from Rhopoint - I got some of the 8G16D ones (Econistors) and they're running in now - very impressive already.
I think the passive tone stack with offbrd pot/switched R's is a good simple starting point with a 7 band ("similar to" Palette" type) filter format - so we would be looking at input buffer, tone stack, a gain stage & vol control with low o/pZ or another buffer, so far?
One thing that's seems to have dissappeared from the headphone community is the treble filter about the 7kHz area to assist with the physical phone-ear generated peak in the response (like the Millet HD4?) - is this valid and worth possible inclusion?
Would it be worth considering the use of LDRs as volume controls instead of pots? The problems of impedance matching and current control would be design problems, but ...
And I am hoping that Ian's I2S FIFO project continues to develop - promising.
I think the passive tone stack with offbrd pot/switched R's is a good simple starting point with a 7 band ("similar to" Palette" type) filter format - so we would be looking at input buffer, tone stack, a gain stage & vol control with low o/pZ or another buffer, so far?
One thing that's seems to have dissappeared from the headphone community is the treble filter about the 7kHz area to assist with the physical phone-ear generated peak in the response (like the Millet HD4?) - is this valid and worth possible inclusion?
Would it be worth considering the use of LDRs as volume controls instead of pots? The problems of impedance matching and current control would be design problems, but ...
And I am hoping that Ian's I2S FIFO project continues to develop - promising.
Hi,
Yeah, they so much fly under radar, totally unjustified...
I kind of would like (if we do this) just have an EQ module. I'd put Footprints for Pots that can take Alps Blue or similar on the PCB, for people who pay for Elma switches, use wire.
I don't really want to get into the rest of the circuitry, as everyone has their own special ideas of what is best, which leads to arguments I want to avoid, as they are not productive. The passive circuit would be around 3k or so input impedance in the midrange/treble for the controls flat, so it needs a beefy buffer to drive it... Output impedance is variable but low, load will be 10K fixed...
I'm really not great on 'cans. In the 80's I used Koss electrostatics with Crossfeed and EQ but only if I absolutely had to. Can't stand regular ones at all. Nowadays I use Audio Technica Noise Cancelling Phones, primarily for the noise cancellation, when travelling.
I am not impressed with LDR controls, but some swear by them. It is the sort of debate I'd like to avoid. Use whatever works for you...
If I'd build this for myself I'd have gain trim controls and likely physiological EQ embedded in the input buffer to handle program level differences, then passive EQ, then 2nd gainstage with gain variation so that the gain gets dropped when not needed. This probably needs something like a 6-Deck switch (gain adjustment, output level adjustment and physiological EQ. And I'd probably have a set of indicators for average levels there somewhere.
But that's just me.
Ciao T
Yeah, they so much fly under radar, totally unjustified...
I kind of would like (if we do this) just have an EQ module. I'd put Footprints for Pots that can take Alps Blue or similar on the PCB, for people who pay for Elma switches, use wire.
I don't really want to get into the rest of the circuitry, as everyone has their own special ideas of what is best, which leads to arguments I want to avoid, as they are not productive. The passive circuit would be around 3k or so input impedance in the midrange/treble for the controls flat, so it needs a beefy buffer to drive it... Output impedance is variable but low, load will be 10K fixed...
I'm really not great on 'cans. In the 80's I used Koss electrostatics with Crossfeed and EQ but only if I absolutely had to. Can't stand regular ones at all. Nowadays I use Audio Technica Noise Cancelling Phones, primarily for the noise cancellation, when travelling.
I am not impressed with LDR controls, but some swear by them. It is the sort of debate I'd like to avoid. Use whatever works for you...
If I'd build this for myself I'd have gain trim controls and likely physiological EQ embedded in the input buffer to handle program level differences, then passive EQ, then 2nd gainstage with gain variation so that the gain gets dropped when not needed. This probably needs something like a 6-Deck switch (gain adjustment, output level adjustment and physiological EQ. And I'd probably have a set of indicators for average levels there somewhere.
But that's just me.
Ciao T
Hello all,
Here is a 6 section Baxandall circuit that emulates the behavior of the Cello EQ. I am posting this with the sole purpose of inviting conversation. I conjured this up in a couple of hours using CircuitMaker 2000. I would expect it to work should someone want to build it. If anyone here wants the CircuitMaker project files or a PDF that gives much better detail than this PIC please email me.
Here is a 6 section Baxandall circuit that emulates the behavior of the Cello EQ. I am posting this with the sole purpose of inviting conversation. I conjured this up in a couple of hours using CircuitMaker 2000. I would expect it to work should someone want to build it. If anyone here wants the CircuitMaker project files or a PDF that gives much better detail than this PIC please email me.
I would get the latest WMP and then a FLAC plug in. I alos think there have been some software upgrades, which you should be able to get for free.
I put all mu computer music on FLAC losless format.
Kevin,
Sorry, but I got so "P'd off" with Levinson, his "international Dac designer" of the "Daniel Hertz USB Dac" rubbish and Dick Burwen himself, that I wouldn't waste any more time there!
Thanks for the suggestion, tho.
As Thorsten mentioned, there's a couple of good DSP packages available now that include many extras, operate without WMP and functions on Flac format - Jeremy "qusp" is working with one that includes the adjustable Xover and outputs via dual I2S signal paths and Ian's FIFO project looks very promising to complement the Sabre dac but also my ol' 1541A project too.
Still looking forward to this analogue "Tone Stack" based control centre.
Carl,
Interesting that the filter at 5kHz would be just about right to reduce much of the headphone treble problems, or perhaps later on could have an added switched option to move it up.
Drawn like that, it appears very simple!
Sorry, but I got so "P'd off" with Levinson, his "international Dac designer" of the "Daniel Hertz USB Dac" rubbish and Dick Burwen himself, that I wouldn't waste any more time there!
Thanks for the suggestion, tho.
As Thorsten mentioned, there's a couple of good DSP packages available now that include many extras, operate without WMP and functions on Flac format - Jeremy "qusp" is working with one that includes the adjustable Xover and outputs via dual I2S signal paths and Ian's FIFO project looks very promising to complement the Sabre dac but also my ol' 1541A project too.
Still looking forward to this analogue "Tone Stack" based control centre.
Carl,
Interesting that the filter at 5kHz would be just about right to reduce much of the headphone treble problems, or perhaps later on could have an added switched option to move it up.
Drawn like that, it appears very simple!
No problems as a frustrated customer you have paid for the right to be p*ssed. I wouldn't deal with Livinson just Burwen and the software. I am sure one could set up some of the software packages to have filters with the same center freq and Q that Burwen uses, as pointed out the selections used for the Cello Palette were very well chosen and as you point out the UI for the software is very end user friendly.
He is tied to WMP due to his choice of Excel to program the system. I would guess to implement what he did in C++ or spmething was beyond his capability as a programmer. Excel requires that one know the math behind the filters wheras Hard coding a system and the player would require a LOT of programming My guess is that he wrote it for homself and later decided to market it.
He is tied to WMP due to his choice of Excel to program the system. I would guess to implement what he did in C++ or spmething was beyond his capability as a programmer. Excel requires that one know the math behind the filters wheras Hard coding a system and the player would require a LOT of programming My guess is that he wrote it for homself and later decided to market it.
Hi,
I have various player packages that all take "Pro" Plugins in VST format. One Plugin I happen to have is the Waves REQ:
The DSP engine is not bad at all, but usability is not very good for a palette style EQ, it has too many faetures and controls on the surface.
My main concern with this style is that we must daisychain six Op-Amp's to get six bands.
One could of ource run the bands in parallel, even on one Op-Amp, if we make sure to buffer some of the bands. Or we could go straight to the LCR based Baxandall style like the Urei 437 EQ:
http://www.waltzingbear.com/Schematics/Urei/537.JPG
On the other hand there are other types of parallel EQ's like those used in the discontinued NTI Nightpro EQ3D, schematics for which can be found in the public domain. Here a review by Sound on Sound:
NTI Nightpro EQ3D
If we look again at the daisychained Baxandall, there is no reason why we cannot connect all bands in parallel. If we do so, we can only transform them to the passive versions.
Finally, we may use an extreme "passive" style like shown in the attached guitar EQ...
Ciao T
I have various player packages that all take "Pro" Plugins in VST format. One Plugin I happen to have is the Waves REQ:
An externally hosted image should be here but it was not working when we last tested it.
The DSP engine is not bad at all, but usability is not very good for a palette style EQ, it has too many faetures and controls on the surface.
My main concern with this style is that we must daisychain six Op-Amp's to get six bands.
One could of ource run the bands in parallel, even on one Op-Amp, if we make sure to buffer some of the bands. Or we could go straight to the LCR based Baxandall style like the Urei 437 EQ:
http://www.waltzingbear.com/Schematics/Urei/537.JPG
On the other hand there are other types of parallel EQ's like those used in the discontinued NTI Nightpro EQ3D, schematics for which can be found in the public domain. Here a review by Sound on Sound:
NTI Nightpro EQ3D
If we look again at the daisychained Baxandall, there is no reason why we cannot connect all bands in parallel. If we do so, we can only transform them to the passive versions.
Finally, we may use an extreme "passive" style like shown in the attached guitar EQ...
Ciao T
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ThorstenL,
When I was 'futzing' about with the circuit that I posted I tried to come up with a version that had the filters in parallel, but I was never successful. I never found a solution that supported the 3 different gain structures of 18, 12 and 6dB concurrently. Do you have any suggestions?
When I was 'futzing' about with the circuit that I posted I tried to come up with a version that had the filters in parallel, but I was never successful. I never found a solution that supported the 3 different gain structures of 18, 12 and 6dB concurrently. Do you have any suggestions?
