@mikets42 from:
https://www.diyaudio.com/community/...-matter-for-sound.409770/page-22#post-7623770 :
"With Chirp aka Farina method, you don't measure the loudspeaker but how the loudspeaker fits your model of it. Anything that is not in the model is considered as observation noise and rejected. Whenever you err you have no indication how badly you erred. This way you completely reject Barhausen noise. You can not distinguish it from the observation noise.
Thus we have this discussion "Do measurements matter?""
This measurement deficiency leads to the widespread misconception that current-drive only lowers harmonics (mainly D3). Followed by endlessly parroted waffling about the audibility of harmonics. But current-drive does not even lower the D3 at low frequencys.
It lowers the most anoying artefact a dynamic transducer can produce:
Barkhausen Noise.
And this is true for all frequencys.
This is what i found out two decades ago with a series resistor.
By ear. Yes, subjectivly. Without knowing anything.
Best regards
Bernd
https://www.diyaudio.com/community/...-matter-for-sound.409770/page-22#post-7623770 :
"With Chirp aka Farina method, you don't measure the loudspeaker but how the loudspeaker fits your model of it. Anything that is not in the model is considered as observation noise and rejected. Whenever you err you have no indication how badly you erred. This way you completely reject Barhausen noise. You can not distinguish it from the observation noise.
Thus we have this discussion "Do measurements matter?""
This measurement deficiency leads to the widespread misconception that current-drive only lowers harmonics (mainly D3). Followed by endlessly parroted waffling about the audibility of harmonics. But current-drive does not even lower the D3 at low frequencys.
It lowers the most anoying artefact a dynamic transducer can produce:
Barkhausen Noise.
And this is true for all frequencys.
This is what i found out two decades ago with a series resistor.
By ear. Yes, subjectivly. Without knowing anything.
Best regards
Bernd
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"shhh"🙂
...modulated
The only way to find out is to current-drive (e.g. emulated with a series resistor). A resistor will not remedy air leaks and mechanicals.
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Deleted member 375592
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Deleted member 375592
I tried the cheapest compression driver I could find: Dayton Audio PRO8, mounted onto 10" CD horn.
Voltage drive:
Current drive, with 1500Hz HPF 4th order (but without the attached capacitor)
.. which is, essentially, the same as "normal" tweeters - the current drive does not bring any benefits to HF.
Voltage drive:
Current drive, with 1500Hz HPF 4th order (but without the attached capacitor)
.. which is, essentially, the same as "normal" tweeters - the current drive does not bring any benefits to HF.
OK Michael you have convinced me.
Time to design a 2 or 3 way speaker with all the tricks up our sleeves; current drive, passive components, DSP, wave guiding/shaping, neutral ala Purify surround, mutual coupling ie. line arrayed, dual opposed for vibration cancellation, in light thin walled cabinets, (CNC /3D printed))
For lighter, smaller, louder, lower distortion speakers.
30Hz to 20KHz @95dB for that headphone-like smooth, balanced listen-all-night, ready to watch sunrise at the after-party without ringing ears, type of sound.
Let’s collaborate and make that speaker that sets new benchmarks for signal to noise, harmonic distortion, IMD, set new benchmarks in testing eg. FSAF
How can I help?
Time to design a 2 or 3 way speaker with all the tricks up our sleeves; current drive, passive components, DSP, wave guiding/shaping, neutral ala Purify surround, mutual coupling ie. line arrayed, dual opposed for vibration cancellation, in light thin walled cabinets, (CNC /3D printed))
For lighter, smaller, louder, lower distortion speakers.
30Hz to 20KHz @95dB for that headphone-like smooth, balanced listen-all-night, ready to watch sunrise at the after-party without ringing ears, type of sound.
Let’s collaborate and make that speaker that sets new benchmarks for signal to noise, harmonic distortion, IMD, set new benchmarks in testing eg. FSAF
How can I help?
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Deleted member 375592
Great! Let's do it.
I am thinking of a corner line array in a "wife-friendly" format that fits in snugly and does not take up half a room. It should be able to use relatively cheap drivers - but if your budget allows, use whatever you prefer, the sky is the limit. It may look like that:
Dimensions: H=180cm (assuming 8' or 9' ceilings), W=30, D=25...30. The front panel is 60 degrees "in" so you don't have to rotate it.
Configuration: MWMTMWM. Yes, it would be better with more midranges, but the cost...
Tweeter: ribbons like NEO8 or HiVi RTH2 or several ribbons making a longish line, possibly inside a horn to match the midrange's horizontal directivity. Centered at 90cm. Voltage driven, class AB.
Midranges: 5.25". So far, I like Hivi D5.4 as the best IMHO performance-to-price ratio in the sub-$100 range - but I may be mistaken. Placed at the ends and close to the tweeter. Midranges are connected (1+1)||(1+1), and current driven. Drivers are close to the wall intentionally.
Woofers - 6.5". Dayton Audio? Any ideas of 10...15L sub? Yes, it is weak but 8" requires 30+ liters volume which would make it prohibitively large. Closed box. Voltage driven. Class D, TPA325x. It may be capable of producing 40Hz or surely 80Hz, with a separate sub.
The internal volume shall be sectioned per woofers and midranges.
Input - 3 analog STP lines, LF, MF, HF, driven by a 5.1/7.1 sound card controlled by Equalizer APO for consumer-friendly DSP cards are still in their infancy and are such a headache...
The minimum cost heavily depends on country-specific taxes (AFAIK, Norway-made tents cost >2x in Norway vs the USA). I hope to fit into US$1200 per pair for reasonable quality, midrange distortion-wise < 0.1%, on par, or better than B&W 80x.
I have Matlab functions (which can be easily ported to Octave/etc) that can convert "any" measured impulse response of a driver into a desired one, with LR24 (or LR48, or MDS) edges. The result is FIR which most PCs can run inside Equalizer APO without problems. This way you can easily adjust crossover to minimize various distortions in S/W, on your type of music.
Desirable result: an FR-flat IR with minimized tail in your room as it is, and FSAF-measured LTI distortions on real music on your preferred SPL. I would not care much about an anechoic response or THD.
The key question is "How do we debug it?" There surely will be endless silly mistakes made. We have to be able to detect them early and prepare possible solutions / undo / redo. There shall be well-defined steps and criteria for success/failure on each intermediate finish so that you don't end up discovering a problem only after everything is done, polished, painted, and piano-glassed. If we do it, across the globe, and share our experiences, problems, and solutions, we'll be fine (for the most risky and critical sections have been tested). At least, life will be interesting🙂
What do you think? What did I miss? Where erred? Critiques, suggestions, and comments are welcome.
I am thinking of a corner line array in a "wife-friendly" format that fits in snugly and does not take up half a room. It should be able to use relatively cheap drivers - but if your budget allows, use whatever you prefer, the sky is the limit. It may look like that:
Dimensions: H=180cm (assuming 8' or 9' ceilings), W=30, D=25...30. The front panel is 60 degrees "in" so you don't have to rotate it.
Configuration: MWMTMWM. Yes, it would be better with more midranges, but the cost...
Tweeter: ribbons like NEO8 or HiVi RTH2 or several ribbons making a longish line, possibly inside a horn to match the midrange's horizontal directivity. Centered at 90cm. Voltage driven, class AB.
Midranges: 5.25". So far, I like Hivi D5.4 as the best IMHO performance-to-price ratio in the sub-$100 range - but I may be mistaken. Placed at the ends and close to the tweeter. Midranges are connected (1+1)||(1+1), and current driven. Drivers are close to the wall intentionally.
Woofers - 6.5". Dayton Audio? Any ideas of 10...15L sub? Yes, it is weak but 8" requires 30+ liters volume which would make it prohibitively large. Closed box. Voltage driven. Class D, TPA325x. It may be capable of producing 40Hz or surely 80Hz, with a separate sub.
The internal volume shall be sectioned per woofers and midranges.
Input - 3 analog STP lines, LF, MF, HF, driven by a 5.1/7.1 sound card controlled by Equalizer APO for consumer-friendly DSP cards are still in their infancy and are such a headache...
The minimum cost heavily depends on country-specific taxes (AFAIK, Norway-made tents cost >2x in Norway vs the USA). I hope to fit into US$1200 per pair for reasonable quality, midrange distortion-wise < 0.1%, on par, or better than B&W 80x.
I have Matlab functions (which can be easily ported to Octave/etc) that can convert "any" measured impulse response of a driver into a desired one, with LR24 (or LR48, or MDS) edges. The result is FIR which most PCs can run inside Equalizer APO without problems. This way you can easily adjust crossover to minimize various distortions in S/W, on your type of music.
Desirable result: an FR-flat IR with minimized tail in your room as it is, and FSAF-measured LTI distortions on real music on your preferred SPL. I would not care much about an anechoic response or THD.
The key question is "How do we debug it?" There surely will be endless silly mistakes made. We have to be able to detect them early and prepare possible solutions / undo / redo. There shall be well-defined steps and criteria for success/failure on each intermediate finish so that you don't end up discovering a problem only after everything is done, polished, painted, and piano-glassed. If we do it, across the globe, and share our experiences, problems, and solutions, we'll be fine (for the most risky and critical sections have been tested). At least, life will be interesting🙂
What do you think? What did I miss? Where erred? Critiques, suggestions, and comments are welcome.
Hi,
you guys could do it, it's fun activity and in a group everything is more fun than alone, but I'm afraid there is no such single speaker that would work for everyone. For example mikets42 seems to have a nice plan that fits his application very well, and some one else might need some other plan. Both could build equally good speaker even though the speakers were different here and there, and make them actually better than the other for their own use case!
Philosophically one-size-fits all group projects just aren't that good, yet alone best as expected from group effort, in sense that it's compromise of everyone's wishes and contexts but not tailor fit to any of them. Best "performance" is when application is well understood and speakers tailor fit to that budget and aesthetics factored in. In this sense a group project that aims for best is doomed to fail to reach that goal, because it's not best for anyone by definition and as such bit silly activity, even though it would likely teach a lesson or two. So perhaps change the goal to design any number of speakers for each persons own contexts, everyone helping each other out trying to find what that is for everyones context. Like the forum is as a whole, tadaa 🙂 So, all we need is helpful and productive attitude and result ought to be best for everyone.
"30Hz to 20KHz @95dB for that headphone-like smooth, balanced listen-all-night, ready to watch sunrise at the after-party without ringing ears, type of sound." which is by the way loosely description of any good speaker that any speaker should have as a target. 😀 Now put that into your room and practical positioning so figure out listening distance and for how many people is it, figure out budget, make sure manufacturing skills are up to par, and start figuring out what is needed and it's easy to see the "optimal systems" would range from headphones to gigantic desert disco PA. 2cents 🙂
ps. Headphone-like sound requires low / delayed early reflections, so prepare to shrink listening triangle size if necessary, and / or make directional speakers. Try and make headphone sound reach just in front of the practical listening position so that you have two, the traditional home hifi hazy blob sound when relaxing, and the headphone like sound when leaning forward.
you guys could do it, it's fun activity and in a group everything is more fun than alone, but I'm afraid there is no such single speaker that would work for everyone. For example mikets42 seems to have a nice plan that fits his application very well, and some one else might need some other plan. Both could build equally good speaker even though the speakers were different here and there, and make them actually better than the other for their own use case!
Philosophically one-size-fits all group projects just aren't that good, yet alone best as expected from group effort, in sense that it's compromise of everyone's wishes and contexts but not tailor fit to any of them. Best "performance" is when application is well understood and speakers tailor fit to that budget and aesthetics factored in. In this sense a group project that aims for best is doomed to fail to reach that goal, because it's not best for anyone by definition and as such bit silly activity, even though it would likely teach a lesson or two. So perhaps change the goal to design any number of speakers for each persons own contexts, everyone helping each other out trying to find what that is for everyones context. Like the forum is as a whole, tadaa 🙂 So, all we need is helpful and productive attitude and result ought to be best for everyone.
"30Hz to 20KHz @95dB for that headphone-like smooth, balanced listen-all-night, ready to watch sunrise at the after-party without ringing ears, type of sound." which is by the way loosely description of any good speaker that any speaker should have as a target. 😀 Now put that into your room and practical positioning so figure out listening distance and for how many people is it, figure out budget, make sure manufacturing skills are up to par, and start figuring out what is needed and it's easy to see the "optimal systems" would range from headphones to gigantic desert disco PA. 2cents 🙂
ps. Headphone-like sound requires low / delayed early reflections, so prepare to shrink listening triangle size if necessary, and / or make directional speakers. Try and make headphone sound reach just in front of the practical listening position so that you have two, the traditional home hifi hazy blob sound when relaxing, and the headphone like sound when leaning forward.
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Deleted member 375592
Oh, yes, absolutely! Next step shall be wall arrays and back sub, to cancel wall reflections and back wall bass reflection + Matlab scripts how to calculate the FIRs to do that, etc.
By the way, I recently bought HiFiMan 400se, and eq-ed it with FIR and Equalize APO. So far, so good
By the way, I recently bought HiFiMan 400se, and eq-ed it with FIR and Equalize APO. So far, so good
Volts * current is watts or power.
Impedance opposes current and reduces power.
The driver motor converts current to flux that moves the voice coil.
If the hod carrier does not put any bricks on the scaffold no work is getting done.
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It seems we're talking about different things. If the iron 'buffer' at either end of a typical ferrite magnet is not magnetized strongly enough, the field generated by the voice coil will be modulated, depending on its proximity to the iron. So, even if we ignore hysteresis or other 'special' sources of distortion, voltage drive is still prone to inter-modulation distortion in a way that current drive is not.
@mikets42
Have you tried multi-tone tests? Something like 100 Hz + 2kHz? That way, the high frequencies are tested across a large range of coil positions, as with normal program material.
It doesn't decline - it increases towards lower frequencies. Easily cured by EQ.
Regards
Charles
Regards
Charles
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Deleted member 375592
Yes, I did. For example, IMD of Peerless TG9FSD1004, with the voice on 2500Hz and base swept from 80Hz to 200Hz: base’s harmonics fall with frequency increase, voice harmonics, and inter-modulates grow.
I do not know how to interpret these tests.
The easiest to interpret is FSAF residual on real music. You don't need to interpret it, you simply listen to it and subjectively judge the "annoyance" factor vs another driver.
@ETM: at.2035 means the mic used was AudioTechnika AT2035.
HPF on the current drive because the driver comes with a "safety" capacitor that is supposed to be used. Of course, you can drive it with the capacitor only in the voltage drive. In the current drive, you have to limit LF in another way.
Why decline? I can only measure things as accurately as I can, I do not even try to explain them.
Much of this stuff is made up.
You look in the texts there is not a thing called a current amplifier. If you think so go out and purchase one and post a photo.
There is such a thing as a transconductance amplifier. The output current is proportional to the input voltage. Still go out and purchase an audio transconductance amplifier and post a photo.
Audio drivers are complex transducers with very frequency dependent impedance. take your driver out and play with it.
Try voltage feedback.
Try current feedback.
Post your results.
You look in the texts there is not a thing called a current amplifier. If you think so go out and purchase one and post a photo.
There is such a thing as a transconductance amplifier. The output current is proportional to the input voltage. Still go out and purchase an audio transconductance amplifier and post a photo.
Audio drivers are complex transducers with very frequency dependent impedance. take your driver out and play with it.
Try voltage feedback.
Try current feedback.
Post your results.
D
Deleted member 375592
Well, how do really good drivers perform on the current drive? Let's experiment with Audax 130Z10, a highly regarded midrange from the mid-90s. As expected, H2 is not affected much. H3 and H5 - by 20 dB.
@DualTriode - I am curious, what is the basis of your conclusions, if any? BTW, I did look in the texts, for example, https://www.amazon.ca/Current-Drivi...e/dp/1450544002/ref=sr_1_1?crid=16W7FLLOOWRGH, which I would wholeheartedly recommend you to study before making any claims. You could have noticed that I did measure the complex frequency-dependent impedance of audio drivers (that's actually what I started with). Of course, all measurements are reproducible. Of course, being a mathematician, I am not so stupid as to publish any "fake news". Really, what is your thought process that brought you to the conclusion of anything "made up"? Just ... how???
@DualTriode - I am curious, what is the basis of your conclusions, if any? BTW, I did look in the texts, for example, https://www.amazon.ca/Current-Drivi...e/dp/1450544002/ref=sr_1_1?crid=16W7FLLOOWRGH, which I would wholeheartedly recommend you to study before making any claims. You could have noticed that I did measure the complex frequency-dependent impedance of audio drivers (that's actually what I started with). Of course, all measurements are reproducible. Of course, being a mathematician, I am not so stupid as to publish any "fake news". Really, what is your thought process that brought you to the conclusion of anything "made up"? Just ... how???
This is true. There is no single best for everyone. Humans are far too complex (and strange) for that. There’s no best speaker, best screen, best car, best wife or husband or best antibiotic for everyone
Humans don't live long enough, and we forget too quickly. But if we step back and take a look at the history of say, the recording, transmission and playback of pictures, or motion pictures, things have never been better, and prices have never been lower.
As I was walking down the aisle of my local supermarket, I could see BT enable earphones that cost $19.
Imagine telling someone. who, just some 80 years ago, watched Fantasia (1940, first commercial film presented in stereo sound) that in the future, she could listen to any speech or song through earpieces transmitted through the air via a pocket device... or that in the future, movie soundtracks or score may not need entire Philadelphia Orchestra, but could be done in-the-box by one (gifted multi-instrumentalist)
As single creatures, most of us can do little, but collectively, humans can do amazing (and terrible) things.
@mbrennwa 's OSMC is a good example of successful group project that 6 years ago developed a classic 3 way speaker.. which won't work for EVERYONE, but would far exceed what was generally available 80 years ago in 1x2x1 ft enclosure...
I like to think of HOW it can be done (better), instead of how/ why it can't be done...
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Yeah the forum has quite many members so any project could be good for multiple people. Just make sure the context stays clear for everyone participating to the design so that it gets tailor fit enough 🙂 generic projects are fine as well, can teach a lesson or two.