If you havent read this you should. It will clarify why we as audiophiles swap components to change sound, and what is really going on.
Dynamic Compression
I have been using my behringer deq2496 to EQ but more recently been experimenting with the dynamic EQ which acts as an expander.
Read this article and it will all make sense. No more guess work and swapping to get the exact sound you want. Just manipulate it in real time on a deq.
Dynamic Compression
I have been using my behringer deq2496 to EQ but more recently been experimenting with the dynamic EQ which acts as an expander.
Read this article and it will all make sense. No more guess work and swapping to get the exact sound you want. Just manipulate it in real time on a deq.
Thanks for the alert. Do you set your expander by ear?
I have been using the expander in my DEQ2496 at very moderate setting (+2dB gain, -20dB threshold). From the article perhaps I should be more aggresive . With a gain of say +5dB wouldn't it require a corresponding global gain adjustment of -5dB to prevent clipping when the input signal reaches -5dB and higher?
BTW we're not even talking about the dynamic frequency DEQ function on the DEQ yet
Have you tried playing with the ratio?
I currenly have mine set to +1db, with ratio1:1.2, and -8db thresh hold and it drasticaly improves dynamics.
I am running newform research ribons. They notoriously have a hit or miss interpretation. I am confident the problem is solved with the dynamic expander appled.
As far as the DEQ yes I just inplemented a DEQ on the top 20khz at 1/7 octave .
I do set these by ear, and the system has already been thoroughly EQ by mic, measurement, and consideration of phase minimum points.
My room is heavily damped, and treated with skyline diffusors as well.
I currenly have mine set to +1db, with ratio1:1.2, and -8db thresh hold and it drasticaly improves dynamics.
I am running newform research ribons. They notoriously have a hit or miss interpretation. I am confident the problem is solved with the dynamic expander appled.
As far as the DEQ yes I just inplemented a DEQ on the top 20khz at 1/7 octave .
I do set these by ear, and the system has already been thoroughly EQ by mic, measurement, and consideration of phase minimum points.
My room is heavily damped, and treated with skyline diffusors as well.
Hi,
the above link is imho a misleading source.
The assumptions are simpy wrong.
example: How do they get from the diagram ´Fletcher-Munson-curves to ´inverted F-M-curves´?
´They invert the F-M-diagram and(!) shift the lower curves upwards!
That in itself is a mathematical compression and simply a major failure here.
Seen a different way is, they think that as the ear has a dynamic range of ~120dB at 1kHz it´d be the same at 30Hz.
So they inverted the F-M-diagram and and compressed the resulting ~180dB@30Hz to 120dB.
The right way should be to invert the F-M-diagram and then to truncate everything below 0dB.
This shows the reduced dynamic range of the ear below 1kHz.
Of course their two statements are wrong also due to the earlier failure.
The first example where they state that current compresses but voltage not is - sorry to say- utter rubbish.
If it applied, the rules of physics needed to be redefined.
How comes that in a current loop you can measure the exactly same current value at any(!) point of the loop, while the voltage levels may differ all over the place?
current compression, oh really, huh?
Then jum to the final.
the author says:
"For dynamics to be effective at mid frequencies, it must have a sharper leading transient edge. Compression has a response time. Our hearing is more susceptible to damage at mid frequencies. Our low frequency hearing is more robust."
The sharper leading eadge is simply a function of frequency of the signal.
For the same amplitude the signal with higher frequency has a larger dy/dt, hence the sharper/steeper edge.
If hearing is more robust at low frequencies (what it factually is) how comes that he claimed a larger dynamic range earlier?
He obviusly doesn´t recognize he´s contradicting himself.
In the postscipt he mentions a true dynamic compression mechanism of voicecoil loudspeakers, thermal compression.
Funnily he doesn´t draw the conclusion that it´d be current drive of the amp that would omit with this problem.
The F-M-diagram is a direct readout for the ear´s dynamic range.
There´s no need at all to invert, shift and misinterpret things.
Sorry to say klhsx, but that article doesn´t make sense at all, its almost completely a pile of rubbish.
jauu
Calvin
ps. don´t get mewrong, I don´t critizise the use of EQs .... those can indeed be very beneficial.
the above link is imho a misleading source.
The assumptions are simpy wrong.
example: How do they get from the diagram ´Fletcher-Munson-curves to ´inverted F-M-curves´?
´They invert the F-M-diagram and(!) shift the lower curves upwards!
That in itself is a mathematical compression and simply a major failure here.
Seen a different way is, they think that as the ear has a dynamic range of ~120dB at 1kHz it´d be the same at 30Hz.
So they inverted the F-M-diagram and and compressed the resulting ~180dB@30Hz to 120dB.
The right way should be to invert the F-M-diagram and then to truncate everything below 0dB.
This shows the reduced dynamic range of the ear below 1kHz.
Of course their two statements are wrong also due to the earlier failure.
The first example where they state that current compresses but voltage not is - sorry to say- utter rubbish.
If it applied, the rules of physics needed to be redefined.
How comes that in a current loop you can measure the exactly same current value at any(!) point of the loop, while the voltage levels may differ all over the place?
current compression, oh really, huh?
Then jum to the final.
the author says:
"For dynamics to be effective at mid frequencies, it must have a sharper leading transient edge. Compression has a response time. Our hearing is more susceptible to damage at mid frequencies. Our low frequency hearing is more robust."
The sharper leading eadge is simply a function of frequency of the signal.
For the same amplitude the signal with higher frequency has a larger dy/dt, hence the sharper/steeper edge.
If hearing is more robust at low frequencies (what it factually is) how comes that he claimed a larger dynamic range earlier?
He obviusly doesn´t recognize he´s contradicting himself.
In the postscipt he mentions a true dynamic compression mechanism of voicecoil loudspeakers, thermal compression.
Funnily he doesn´t draw the conclusion that it´d be current drive of the amp that would omit with this problem.
The F-M-diagram is a direct readout for the ear´s dynamic range.
There´s no need at all to invert, shift and misinterpret things.
Sorry to say klhsx, but that article doesn´t make sense at all, its almost completely a pile of rubbish.
jauu
Calvin
ps. don´t get mewrong, I don´t critizise the use of EQs .... those can indeed be very beneficial.
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Hi,
One fundamental problem of the FM curves most don't realise :
Phons are defined as the dB level at 1KHz. The curves equal
loudness to these levels. The FM curves tell you absolutely
nothing about the ears perception of level at 1KHz as it
varies from 0dB to 120db. There is nothing "equal" about
the curves in the vertical direction though it looks like it.
You have no idea what a change of 10 phon sounds like,
i.e. going from 30phon to 40phon is probably not the same
as going from 80phon to 90phon, the information is simply
not in the FM curves.
rgds, sreten.
One fundamental problem of the FM curves most don't realise :
Phons are defined as the dB level at 1KHz. The curves equal
loudness to these levels. The FM curves tell you absolutely
nothing about the ears perception of level at 1KHz as it
varies from 0dB to 120db. There is nothing "equal" about
the curves in the vertical direction though it looks like it.
You have no idea what a change of 10 phon sounds like,
i.e. going from 30phon to 40phon is probably not the same
as going from 80phon to 90phon, the information is simply
not in the FM curves.
rgds, sreten.
Last edited:
The key to using it is to make one change at a time and live with it for a long time. don't change all kinds of stuff at once. Develop your acoustic sense capacity for what adjustments do slowly over time. treat it like auditioning a new amp or speaker, just pick a small change to make, and listen to it. make a yes or no decision about if it improved the sound, then leave it or revert the setting. Do this and over time you will sharpen things up amazingly. Never dream of upgrading anything again.
Calvin, what i take away from the discussion is simply that dynamic relationships are almost more important than flat SPL graphs at a given output.
Specifically the ratio of loud to quiet sounds is kind of more important than flat frequency response in terms of how we perceive sound. Also that our hearing is more sensitive to this phenomena in the stated range.
Practically what it means is play with dynamic compression and do it differently in different frequency ranges.
Specifically the ratio of loud to quiet sounds is kind of more important than flat frequency response in terms of how we perceive sound. Also that our hearing is more sensitive to this phenomena in the stated range.
Practically what it means is play with dynamic compression and do it differently in different frequency ranges.
calvin, I am not sure what you mean.
All they have done is express the frequency response of the ear as if it were a speaker, or a microphone.
Imagine the new curve as the frequency response of a speaker. They did not do any fancy math. It is simply a way to show the frequency response of the ear. Very simple illustration.
They are showing that for a flat input signal, the new curve is what your ear outputs to your brain. Thats all it is.
As for the current ....... where do I even begin? voltage is not affected by conductors in the same way as current is. It has to do with resistance and the diameter of the conductor. A very simple explanation and example was given with high voltage mains throughout cities. The power loss from the conductor happens through putting the energy into current rather than voltage. Thats why main lines are high voltage. To avoid power loss.
Try to keep this very simple instead of making complex out of simple ideas. If a signal is modulated by current, and the current peaks are reduced due to power loss, this is in effect a dynamic compressor. Thats all it means.
In a high voltage circuit, the current variations are smaller to maintain the same power, and the compression due to power loss from current peaks will behave differently. It is probably more involved to illuminate the exact mechanism at lower current levels because you may have other conductor properties at play at low currents just above where the material starts to conduct. Maybe it could even act as an expander? who knows... The point is to start considering the effects of expansion and compression, and not think in terms of a fixed volume SPL reading.
So thank you for your critical analysis, but this article clearly is very valuable if it even made you think about the concepts at all.
All they have done is express the frequency response of the ear as if it were a speaker, or a microphone.
Imagine the new curve as the frequency response of a speaker. They did not do any fancy math. It is simply a way to show the frequency response of the ear. Very simple illustration.
They are showing that for a flat input signal, the new curve is what your ear outputs to your brain. Thats all it is.
As for the current ....... where do I even begin? voltage is not affected by conductors in the same way as current is. It has to do with resistance and the diameter of the conductor. A very simple explanation and example was given with high voltage mains throughout cities. The power loss from the conductor happens through putting the energy into current rather than voltage. Thats why main lines are high voltage. To avoid power loss.
Try to keep this very simple instead of making complex out of simple ideas. If a signal is modulated by current, and the current peaks are reduced due to power loss, this is in effect a dynamic compressor. Thats all it means.
In a high voltage circuit, the current variations are smaller to maintain the same power, and the compression due to power loss from current peaks will behave differently. It is probably more involved to illuminate the exact mechanism at lower current levels because you may have other conductor properties at play at low currents just above where the material starts to conduct. Maybe it could even act as an expander? who knows... The point is to start considering the effects of expansion and compression, and not think in terms of a fixed volume SPL reading.
So thank you for your critical analysis, but this article clearly is very valuable if it even made you think about the concepts at all.
"You can compress current but not voltage". This is nonsense, and the rest of the article isn't much better. The only device in a system that shows compression is the loudspeaker driver. And that is only at high enough levels to heat the coil significantly. And the only way to fix this is with an expander that has the correct ( opposite to the speaker) time constants , and ratio. And these are not constant over freq and time in a speaker. What you are doing is distorting the signal.
But if your happy with the sound go for it. Just don't say it's a fix, it's not.
it does make sense, try not to get bogged down from the new idea, with purist ideals.
Speaker cables, and different kinds of amps sound different this is a logical explanation that has eluded many of us even for a lifetime. you can embrace it and enjoy the improvements, or you can cite the psychological difficulties of your current paradigm.
I leave that up to you.
Speaker cables, and different kinds of amps sound different this is a logical explanation that has eluded many of us even for a lifetime. you can embrace it and enjoy the improvements, or you can cite the psychological difficulties of your current paradigm.
I leave that up to you.
Again when the idea of compression of current or voltage is explained, understand it in terms of a signal modulated in current being compressed. The loses changes the signal. This is the compression.
The non linear behaviour of current in conductors, due to joule heating, and the linear behaviour through the range of voltages.
That is the take away message.
The way these vary in signals has some degree of compression and expansion going on, and we do hear it, and this is why when we measure SPL frequency response and it seems flat and the two amps sound so different and we are missing it.
Yes you would need to make a filter it a perfect inversion of your speaker, and amp to make it perfect. Is it a waste of time to try and account for it in a general way? Try it and tell us . I have and it is amazing how stupid i have been trying different stuff all the time for 17 years, studying physics, and even acoustics masters and missing this concept.
You can intelligently EQ based on an understanding of the sensitivity of hearing in different ranges.
It is not a distortion to try and restore dynamic relationships.
The basic concept is being missed and muddied.
When you look at a colour against another colour, it looks different. I am a painter. I paint portraits, and all kinds of stuff. Colours react against each other, because our nervous system is a difference engine. We literally experience things through comparison. If there was nothing to compare some sense modality to it wouldn't be able to be experienced at all. If you had no lights, how would you describe total darkness. How do you explain cold without hot?
The take away insight is this concept of relative loudness in sounds. And how important that is in making realistic reproduction, and why it is important as a human with the type of mind, body and hearing that we have.
The non linear behaviour of current in conductors, due to joule heating, and the linear behaviour through the range of voltages.
That is the take away message.
The way these vary in signals has some degree of compression and expansion going on, and we do hear it, and this is why when we measure SPL frequency response and it seems flat and the two amps sound so different and we are missing it.
Yes you would need to make a filter it a perfect inversion of your speaker, and amp to make it perfect. Is it a waste of time to try and account for it in a general way? Try it and tell us . I have and it is amazing how stupid i have been trying different stuff all the time for 17 years, studying physics, and even acoustics masters and missing this concept.
You can intelligently EQ based on an understanding of the sensitivity of hearing in different ranges.
It is not a distortion to try and restore dynamic relationships.
The basic concept is being missed and muddied.
When you look at a colour against another colour, it looks different. I am a painter. I paint portraits, and all kinds of stuff. Colours react against each other, because our nervous system is a difference engine. We literally experience things through comparison. If there was nothing to compare some sense modality to it wouldn't be able to be experienced at all. If you had no lights, how would you describe total darkness. How do you explain cold without hot?
The take away insight is this concept of relative loudness in sounds. And how important that is in making realistic reproduction, and why it is important as a human with the type of mind, body and hearing that we have.
The other thing that is helpful for using an EQ is to have a chart of frequency ranges for instruments, and specifically one which shows the fundamental, and then the harmonics. Then you can gauge the transients, and the steady state portions of the sounds of the instruments.
So if you don't hear enough attack you can think about that and refer to the guidelines of the chart.
As for the comment about a speaker distorting dynamics through time well you can EQ dynamically and set the attack and release (google it if you don't know what these are).
So if you don't hear enough attack you can think about that and refer to the guidelines of the chart.
As for the comment about a speaker distorting dynamics through time well you can EQ dynamically and set the attack and release (google it if you don't know what these are).
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