Hi All,
Full disclosure, this post may be a bit of a ramble! I've written it twice now and deleted the whole thing as it went on for too long.
Shorty synopsis is this, I'm now in my late 30's and working as a professional design engineer. I've been offered jobs as head design engineer with some very prestigious loudspeaker companies. I've chosen not to as my career is actually more related to doing something nice for humanity as a whole (something a bit more fundamental than listening to music, as good speakers already exist and this is a hobby!)
I've been interested in loudspeaker design since I was 14. I'm a musician, I've worked in recording studios etc.... probably similar story to most members here!
As the years have passed I've learnt to be more professional and less... well c**ty. decades ago I asked stupid questions and gave stupid advice... I now often see people posting on the loudspeaker forums with similar bad advice or ideas.
For a while I was leaving snarky comments - honestly trying to steer people away from folly, but probably not done in the nicest way, so sorry about that.
Going full circle, I feel that I should try to give something positive back - some useful tests and advice that people starting out, who want to approach this hobby from an engineering and not emotive perspective, can use.
So here's my suggestion, I'd like to do some propper documented testing on things and share them with users here... but I'd like to check what people are interested in, if other members agree this would be useful and check for input on test procedure before it is standardised.
It's my position that modern (i.e. recently released) loudspeaker drivers are of excellent quality, from SB acoustics to purifi, there's some really amazing stuff out there.
I think the biggest thing we can do as loudspeaker designers is learn to make cabinets that bring out the best in these drivers and choose an effective system implementation (i.e. passive xo, line level xo or dsp, passive or active speaekers etc).
With that in mind, I was thinking of performing and publishing the following tests; if these already exist please let me know not to bother and where to find them!
For crossover components:
Measuring and comparing different capacitors, resistors and inductors.
Measuring THD/noise and signal integrity at a set voltage level OUT of the component.
For Cabinets:
Measuring the effect of sound reflections in the cabinet which emit back through the speaker cone. Using one or two different 'control drivers' within an acoustically open rig, likely a large baffle (2m*1.2m?) With different open boxes behind. Starting with a flat surface at different distances from the rear of the driver, followed up by adding different damping materials and different shapes.
- I know this has been discussed as a known source of noise on speakers, B&W had a matrix internal system and of course the nautilus, and it's discussed in many textbooks, but I haven't seen a methodical test to show the difference between distance to rear panel, angle of panel (or shapes, if using cones/pyramids/tiles) and different damping materials (foam, polystuff, wool)
After completing that I will probably try to contribute a few designs, with full open documentation for XO's and cabinet drawings etc. I will likely only do 2 as I do intend to launch my own loudspeaker company in 2023.
(mods - please move this post if it's in the wrong place)
Full disclosure, this post may be a bit of a ramble! I've written it twice now and deleted the whole thing as it went on for too long.
Shorty synopsis is this, I'm now in my late 30's and working as a professional design engineer. I've been offered jobs as head design engineer with some very prestigious loudspeaker companies. I've chosen not to as my career is actually more related to doing something nice for humanity as a whole (something a bit more fundamental than listening to music, as good speakers already exist and this is a hobby!)
I've been interested in loudspeaker design since I was 14. I'm a musician, I've worked in recording studios etc.... probably similar story to most members here!
As the years have passed I've learnt to be more professional and less... well c**ty. decades ago I asked stupid questions and gave stupid advice... I now often see people posting on the loudspeaker forums with similar bad advice or ideas.
For a while I was leaving snarky comments - honestly trying to steer people away from folly, but probably not done in the nicest way, so sorry about that.
Going full circle, I feel that I should try to give something positive back - some useful tests and advice that people starting out, who want to approach this hobby from an engineering and not emotive perspective, can use.
So here's my suggestion, I'd like to do some propper documented testing on things and share them with users here... but I'd like to check what people are interested in, if other members agree this would be useful and check for input on test procedure before it is standardised.
It's my position that modern (i.e. recently released) loudspeaker drivers are of excellent quality, from SB acoustics to purifi, there's some really amazing stuff out there.
I think the biggest thing we can do as loudspeaker designers is learn to make cabinets that bring out the best in these drivers and choose an effective system implementation (i.e. passive xo, line level xo or dsp, passive or active speaekers etc).
With that in mind, I was thinking of performing and publishing the following tests; if these already exist please let me know not to bother and where to find them!
For crossover components:
Measuring and comparing different capacitors, resistors and inductors.
Measuring THD/noise and signal integrity at a set voltage level OUT of the component.
For Cabinets:
Measuring the effect of sound reflections in the cabinet which emit back through the speaker cone. Using one or two different 'control drivers' within an acoustically open rig, likely a large baffle (2m*1.2m?) With different open boxes behind. Starting with a flat surface at different distances from the rear of the driver, followed up by adding different damping materials and different shapes.
- I know this has been discussed as a known source of noise on speakers, B&W had a matrix internal system and of course the nautilus, and it's discussed in many textbooks, but I haven't seen a methodical test to show the difference between distance to rear panel, angle of panel (or shapes, if using cones/pyramids/tiles) and different damping materials (foam, polystuff, wool)
After completing that I will probably try to contribute a few designs, with full open documentation for XO's and cabinet drawings etc. I will likely only do 2 as I do intend to launch my own loudspeaker company in 2023.
(mods - please move this post if it's in the wrong place)
My personal view on loudspeakers:
Audio speakers are the most important part in an audio system and have to do some system determining things:
-to convert electrical energy into acoustic (mechanical) energy waves
-to cover the whole frequency range a human is able to hear
-to be able to reproduce that whole freq. range with a given level of dB, that means flat response on the listeners place in a given room
-to be able to reproduce (and to produce?) a broad palete of sound colors from the incoming electric signals.
So how good are todays speakers really leads to the method of valuation that can be applied to this goal, in order to rank different speakers like its been most often done.
You say, we have, technically, near perfect speakers today.
Which method do you apply to make such a statement?
Most engineers would say, I have measured the speaker and this gives me enough data to compare with others and to judge the speaker.
Is this really the last word in judging a speaker system, to rely on measurements only?
I know, measurements are the only objective facts we have, all personal judging couldn't be objective but is highly subjective.
So lets face the reality: should the speaker system pleases a measurement freak or should it serve an musical mind? Or, to say it the other way, should a speaker just reproduce what comes into it and sound mostly neutral or should it be an active device that alters the incoming sound and reproduce music the way an instrument does?
This will lead us towards a rail switch: those, who want absolute neutral speakers should look at the studio speakers, because this is one of the highest demands in this sector.
But in the home audio sector, we have gone away from the measurements as highest ranked criteria for speakers and gone towards a listener oriented, good sounding speaker.
This means, the highest criteria for ranking speakers has gone from objective to a subjective standpoint and thats what we see today in most audio magazines. Speakers are being tested, some measurements were published (most interesting: efficiency), and the last word has the music oriented listener who judges the speaker.
So, what has been left of the statement regarding the perfect speakers we have today?
Nearly nothing, because as the judging has become subjective, everyone could see this different. Measurements are only a hint to the real sound of the speaker, which is judged by the listener.
And thats exactly what is happening in other fields of physics: for example optics.
When Leica, for e.g., engineers a new lens, the last word for the acceptance has whom?
The design team on an optical point of view, that includes all measurements that has been necessary for the development of the lens, but on a heavy focus of how the lens reproduces the reality. And that happens in the last instance by looking of the pics reproduced by the lens. Even in this field, measurements are necessary, but the last instance for different lens designs aren't the measurements alone, but the optical view of the pics.
So it is with speakers today. The last instance to judge a speaker has to be the listener.
I would like to come to a another of those points made in the beginning:
The word LOUDspeaker says it all. How efficient is a speaker today and do we have good speakers if thats the highest ranked criteria.
Lets face it: Most speaker manufacturers have gone some steps behind LOUD, towards quietspeakers.
Why is that and is that ideal for the audio system?
It is, because speakers have to fit the audio amps, and those amps have skyrocket in power output the last decades. Now we have amps, that can reproduce high power levels and those we are combining with quietspeakers instead of loudspeakers. Is that an ideal combination? Of course, everyone who is familiar with amp design knows, its not. It can't be. Because to design an amp with high power output AND excellent quality is nearly impossible, but to design an amp with low power output combined with highest quality is a relative easy task. So why don't we have those high efficiency speakers, that are able to make the most out of the smallest input signals? Because nobody on the mass market wants them anymore, and even the highend manufacturers like to produce big power output amps, which then being combined with quietspeakers. Thats the main sector of highend audio today, to produce those speakers for that kind of amps.
Do a game and run around attending an audio fair and ask speaker companies what they can offer above 90dB effiency. Most of them can offer nothing. But in the past, as amp power output wasn't as big as today, that was standard. And even efficiency above 100dB wasn't unusual.
So mostly on offer today we have the wrong speakers with too low efficiency, combining them with the wrong amps.
Lets come to the point of a flat frequency response of speakers.
As we have most often multi- way speakers, the crossovers are very complex and lower the efficiency of a given speaker rapidly.
Why do we have those complex designs today, when its possible to cover the whole frequency range with simple crossovers and a two way speaker?
Because today, every designer builds chassis, which can do one thing perfect, but that isn't covering a broad range of frequencies. The chassis are good in a given freq. range and thats it. Most often this range is small, so that the user have to buy more chassis. Good for the manufacturer, bad for the speakers efficiency, because a chassis with low efficiency paired with a complex crossover results in what? An even lower efficiency speaker!
But thats no problem says the marketing, use it with an amp that produces high power output. We have learned, that this claim is not what leads towards the goal, because it leads never towards highest quality in sound.
When we come to speaker cabinets, most often today the WAF and other aesthetic arguments count heavily, the fashion on speakers looks change with time and the materials used for the cabinets, too.
Does those factors are only optical, aesthetical nature or do they affect the sound?
We have seen a trend to smaller and smaller chassis and cabinets over decades, but those small cabs should reproduce the lowest notes with ease and fast as lighting. Is that possible? Of course, its not, the physics are against it! To move a small, whimpy woofers cone half an inch out of the cabinet to reproduce, say 50 Hz takes time and the bass will sound never fast and quick, more soft and slow. The big, high efficiency 15 inch does the trick in its huge cabinet with ease and when he has finished and standing in a new start position for the next wave to reproduce, the whimpy woofer didn't even finish the first impule.
What did Gorbatchev said? Those who come to late are being punished by life itself (or by the next heavy music impulse, the woofer said).
Those who think a woofer can be installed in the side panels of a cabinet to radiate towards the wall may learn, that even a good woofer is locatable, because its most often not a sub woofer.
But that trick many speaker producers use in their small design cabs, for having the room to install a bigger woofer at all (because they hear, what physics need to reproduce good deep sounds).
The last point I want to make on the so perfect speakers we have today is the ability to reproduce sound colors.
Ever heard the difference between a Guaneri del Gesu and a Stradivari violin?
Never, even if you have played two records and compared them, means two violinists playing those two different sounding instruments, fortunately with the same interpretation of a classical music piece?
With todays quietspeakers and complex crossovers that most often sound as if the musicians are playing several roadblocks away from the listener, don't wonder why.
You need to hear the reproduced music right in your face, so that its possible to impress the listener, shocks him (or her), and makes possible to hear even the smallest difference in those recordings of instruments. AND being able to reproduce (or to produce?) those sounds that came close to the original instruments.
Who is the judge for that sound of those instruments reproduced on a speaker?
The measurement system? The listener with a musical mind?
And if later, why are todays modern speakers so far away from the sound of original instruments like nothing else? Even if they promise to have made so much progress in the past, and still not being able to do such a simple thing like reproducing original sound colors of instruments? Or at least, nearly identical sounding, so that we can audition the difference between those two instruments.
I think thats enough to think about it, and see what shartcomings todays speakers most often have and in which sectors they have to change to bring an optimum result to the listener.
Audio speakers are the most important part in an audio system and have to do some system determining things:
-to convert electrical energy into acoustic (mechanical) energy waves
-to cover the whole frequency range a human is able to hear
-to be able to reproduce that whole freq. range with a given level of dB, that means flat response on the listeners place in a given room
-to be able to reproduce (and to produce?) a broad palete of sound colors from the incoming electric signals.
So how good are todays speakers really leads to the method of valuation that can be applied to this goal, in order to rank different speakers like its been most often done.
You say, we have, technically, near perfect speakers today.
Which method do you apply to make such a statement?
Most engineers would say, I have measured the speaker and this gives me enough data to compare with others and to judge the speaker.
Is this really the last word in judging a speaker system, to rely on measurements only?
I know, measurements are the only objective facts we have, all personal judging couldn't be objective but is highly subjective.
So lets face the reality: should the speaker system pleases a measurement freak or should it serve an musical mind? Or, to say it the other way, should a speaker just reproduce what comes into it and sound mostly neutral or should it be an active device that alters the incoming sound and reproduce music the way an instrument does?
This will lead us towards a rail switch: those, who want absolute neutral speakers should look at the studio speakers, because this is one of the highest demands in this sector.
But in the home audio sector, we have gone away from the measurements as highest ranked criteria for speakers and gone towards a listener oriented, good sounding speaker.
This means, the highest criteria for ranking speakers has gone from objective to a subjective standpoint and thats what we see today in most audio magazines. Speakers are being tested, some measurements were published (most interesting: efficiency), and the last word has the music oriented listener who judges the speaker.
So, what has been left of the statement regarding the perfect speakers we have today?
Nearly nothing, because as the judging has become subjective, everyone could see this different. Measurements are only a hint to the real sound of the speaker, which is judged by the listener.
And thats exactly what is happening in other fields of physics: for example optics.
When Leica, for e.g., engineers a new lens, the last word for the acceptance has whom?
The design team on an optical point of view, that includes all measurements that has been necessary for the development of the lens, but on a heavy focus of how the lens reproduces the reality. And that happens in the last instance by looking of the pics reproduced by the lens. Even in this field, measurements are necessary, but the last instance for different lens designs aren't the measurements alone, but the optical view of the pics.
So it is with speakers today. The last instance to judge a speaker has to be the listener.
I would like to come to a another of those points made in the beginning:
The word LOUDspeaker says it all. How efficient is a speaker today and do we have good speakers if thats the highest ranked criteria.
Lets face it: Most speaker manufacturers have gone some steps behind LOUD, towards quietspeakers.
Why is that and is that ideal for the audio system?
It is, because speakers have to fit the audio amps, and those amps have skyrocket in power output the last decades. Now we have amps, that can reproduce high power levels and those we are combining with quietspeakers instead of loudspeakers. Is that an ideal combination? Of course, everyone who is familiar with amp design knows, its not. It can't be. Because to design an amp with high power output AND excellent quality is nearly impossible, but to design an amp with low power output combined with highest quality is a relative easy task. So why don't we have those high efficiency speakers, that are able to make the most out of the smallest input signals? Because nobody on the mass market wants them anymore, and even the highend manufacturers like to produce big power output amps, which then being combined with quietspeakers. Thats the main sector of highend audio today, to produce those speakers for that kind of amps.
Do a game and run around attending an audio fair and ask speaker companies what they can offer above 90dB effiency. Most of them can offer nothing. But in the past, as amp power output wasn't as big as today, that was standard. And even efficiency above 100dB wasn't unusual.
So mostly on offer today we have the wrong speakers with too low efficiency, combining them with the wrong amps.
Lets come to the point of a flat frequency response of speakers.
As we have most often multi- way speakers, the crossovers are very complex and lower the efficiency of a given speaker rapidly.
Why do we have those complex designs today, when its possible to cover the whole frequency range with simple crossovers and a two way speaker?
Because today, every designer builds chassis, which can do one thing perfect, but that isn't covering a broad range of frequencies. The chassis are good in a given freq. range and thats it. Most often this range is small, so that the user have to buy more chassis. Good for the manufacturer, bad for the speakers efficiency, because a chassis with low efficiency paired with a complex crossover results in what? An even lower efficiency speaker!
But thats no problem says the marketing, use it with an amp that produces high power output. We have learned, that this claim is not what leads towards the goal, because it leads never towards highest quality in sound.
When we come to speaker cabinets, most often today the WAF and other aesthetic arguments count heavily, the fashion on speakers looks change with time and the materials used for the cabinets, too.
Does those factors are only optical, aesthetical nature or do they affect the sound?
We have seen a trend to smaller and smaller chassis and cabinets over decades, but those small cabs should reproduce the lowest notes with ease and fast as lighting. Is that possible? Of course, its not, the physics are against it! To move a small, whimpy woofers cone half an inch out of the cabinet to reproduce, say 50 Hz takes time and the bass will sound never fast and quick, more soft and slow. The big, high efficiency 15 inch does the trick in its huge cabinet with ease and when he has finished and standing in a new start position for the next wave to reproduce, the whimpy woofer didn't even finish the first impule.
What did Gorbatchev said? Those who come to late are being punished by life itself (or by the next heavy music impulse, the woofer said).
Those who think a woofer can be installed in the side panels of a cabinet to radiate towards the wall may learn, that even a good woofer is locatable, because its most often not a sub woofer.
But that trick many speaker producers use in their small design cabs, for having the room to install a bigger woofer at all (because they hear, what physics need to reproduce good deep sounds).
The last point I want to make on the so perfect speakers we have today is the ability to reproduce sound colors.
Ever heard the difference between a Guaneri del Gesu and a Stradivari violin?
Never, even if you have played two records and compared them, means two violinists playing those two different sounding instruments, fortunately with the same interpretation of a classical music piece?
With todays quietspeakers and complex crossovers that most often sound as if the musicians are playing several roadblocks away from the listener, don't wonder why.
You need to hear the reproduced music right in your face, so that its possible to impress the listener, shocks him (or her), and makes possible to hear even the smallest difference in those recordings of instruments. AND being able to reproduce (or to produce?) those sounds that came close to the original instruments.
Who is the judge for that sound of those instruments reproduced on a speaker?
The measurement system? The listener with a musical mind?
And if later, why are todays modern speakers so far away from the sound of original instruments like nothing else? Even if they promise to have made so much progress in the past, and still not being able to do such a simple thing like reproducing original sound colors of instruments? Or at least, nearly identical sounding, so that we can audition the difference between those two instruments.
I think thats enough to think about it, and see what shartcomings todays speakers most often have and in which sectors they have to change to bring an optimum result to the listener.
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Um... my point was about what tests could be useful to people designing speaker cabinets by presenting them with factual information about loudspeaker cabinet design and choice of crossover components.
Whilst I enjoyed reading your comments and opinion I couldn't see how it linked to the OP?
Whilst I enjoyed reading your comments and opinion I couldn't see how it linked to the OP?
I think you're limiting application of your expertise. 1) To box speakers. 2) To passive crossovers.
I know there's a "high end" even in the context of DIY. To me, part of DIY is the minimization of expense. It gets really fun when you can still do really well in the limit as expense goes to Zero.
An example might be, I want to cross at 100 Hz. How expensive are those coils going to be? Possibly most of if not more than the cost of my whole amplifier with integrated DSP.
Obviously, Box speakers are more expensive (materials / time) than other speaker driver arrangements that clearly are capable of projecting good sound.
I realize there's a certain convenience to a passive Xover (works with any amplifier) and a box speaker (can toss it up on a bookshelf and it still works). But I feel taken together, it's a highly focused area and the same engineering knowledge, practical expertise and wisdom could be applied more broadly.
Especially in the context of DIY, where the general attraction is that you can do as good or better for far less.
I know there's a "high end" even in the context of DIY. To me, part of DIY is the minimization of expense. It gets really fun when you can still do really well in the limit as expense goes to Zero.
An example might be, I want to cross at 100 Hz. How expensive are those coils going to be? Possibly most of if not more than the cost of my whole amplifier with integrated DSP.
Obviously, Box speakers are more expensive (materials / time) than other speaker driver arrangements that clearly are capable of projecting good sound.
I realize there's a certain convenience to a passive Xover (works with any amplifier) and a box speaker (can toss it up on a bookshelf and it still works). But I feel taken together, it's a highly focused area and the same engineering knowledge, practical expertise and wisdom could be applied more broadly.
Especially in the context of DIY, where the general attraction is that you can do as good or better for far less.
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What do you mean by "what tests" ?
Do mean, what kind of measurements or listening tests ?
Thanks Jan! Maybe 'what's the point' was a bit too pesimistic a title, think I might try one more time with a 'how to give back to the DIY community... What measurements and information would be useful that isn't already available for loudspeaker design'!
Yeah please do post, all kinds of measurement / inspection stuff is interesting. Member Augerpro has done and posted many tests on various cabinet constructions but I'm not sure if anyone has attempted to measure what comes back through the cone. I believe you must figure out how to do it properly and that might be mucho fun 🙂 I suspect some kind of infinite baffle setup with detachable cabinet on the back and then compare?
In general, it doesn't have to be anything specific you post. I suggest that you start building / prototyping something that you think would be a great speaker. Then think critically what you are doing, how to improve things that need improving to get really good system for the design goal. I suspect you'll find very interesting stuff to test on the way if you do question the tradition. Please post those 😉
As jjasniew expressed one might end up with a system that doesn't actually need an enclosure. That said, it would be really nice if there was data on how the sound within enclosure would leak through the cone or not. But I think more interesting might be build few boxes that try to minimize such effect and compare those to find a box inner construction that has minimal effect on the response. Is there any difference at all and what the difference might be in general? how to spot issue from impedance graph or frequency response and what to do about it? The end result would be very useful practical information for DIY enthusiasts. What do you think?
In general, it doesn't have to be anything specific you post. I suggest that you start building / prototyping something that you think would be a great speaker. Then think critically what you are doing, how to improve things that need improving to get really good system for the design goal. I suspect you'll find very interesting stuff to test on the way if you do question the tradition. Please post those 😉
As jjasniew expressed one might end up with a system that doesn't actually need an enclosure. That said, it would be really nice if there was data on how the sound within enclosure would leak through the cone or not. But I think more interesting might be build few boxes that try to minimize such effect and compare those to find a box inner construction that has minimal effect on the response. Is there any difference at all and what the difference might be in general? how to spot issue from impedance graph or frequency response and what to do about it? The end result would be very useful practical information for DIY enthusiasts. What do you think?
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In 1980 I built my own mobile disco.
I used 2 cabinets with 2 Fane 12-50WRMS drivers in each.
Frequency response of speakers to 3KHz.
In the following years no one ever complained about the sound, except too loud sometimes.
Also the audio was mono mixed from stereo into one channel.
I used 2 cabinets with 2 Fane 12-50WRMS drivers in each.
Frequency response of speakers to 3KHz.
In the following years no one ever complained about the sound, except too loud sometimes.
Also the audio was mono mixed from stereo into one channel.
Its interesting to see waterfall plots which shows how much the driver or cabinet
continues to ring.
I would assume lightly lining the cabinet and doing a heavy stuff
has been somewhat been shown before. As far as simple bookshelf speakers.
but I think it would be interesting to see likely where bracing
really pays off. Would be subwoofer cabinets.
Starting with a poorly braced enclosure.
Then progressing with common window braces.
And be able to see waterfall plots showing ringing.
Also likely the distance of a rear baffle, has always been a interest of mine.
To see real world measurements.
In a model 3 cubic feet is 3 cubic feet.
But if the rear baffle is 10" away or 18" away does it matter?
Maybe, maybe not. The actual wavelengths below 200Hz
are incredible longer than any box.
Far as crossover "upgrades" be really nice to debunk or prove.
Some almost ridiculous component cost for 10 to 40 watt speakers.
Really assume that in the 10 to 40 watt range it really doesnt matter.
Likely the real find would be in 100 to 500 watt live sound area.
Where excessive voltage or current would actually finally yield.
Measurable distortion....or does it matter. Because the cone
is already at 3...4..5 % distortion.
Either way if all has been done before. Real world measurments
are always interesting.
For the most part as mentioned, some people just like basic build
guides for specific drivers. Here is the woofer...here is the tweeter.
Here is the crossover. and the pretty flat measurement at the end.
All been done before. But holds up a real value for many.
Who dont have the equipment to measure and design crossovers.
continues to ring.
I would assume lightly lining the cabinet and doing a heavy stuff
has been somewhat been shown before. As far as simple bookshelf speakers.
but I think it would be interesting to see likely where bracing
really pays off. Would be subwoofer cabinets.
Starting with a poorly braced enclosure.
Then progressing with common window braces.
And be able to see waterfall plots showing ringing.
Also likely the distance of a rear baffle, has always been a interest of mine.
To see real world measurements.
In a model 3 cubic feet is 3 cubic feet.
But if the rear baffle is 10" away or 18" away does it matter?
Maybe, maybe not. The actual wavelengths below 200Hz
are incredible longer than any box.
Far as crossover "upgrades" be really nice to debunk or prove.
Some almost ridiculous component cost for 10 to 40 watt speakers.
Really assume that in the 10 to 40 watt range it really doesnt matter.
Likely the real find would be in 100 to 500 watt live sound area.
Where excessive voltage or current would actually finally yield.
Measurable distortion....or does it matter. Because the cone
is already at 3...4..5 % distortion.
Either way if all has been done before. Real world measurments
are always interesting.
For the most part as mentioned, some people just like basic build
guides for specific drivers. Here is the woofer...here is the tweeter.
Here is the crossover. and the pretty flat measurement at the end.
All been done before. But holds up a real value for many.
Who dont have the equipment to measure and design crossovers.
Thanks guys for the feedback, yes it's largely looking at how geometry behind the cone affects what is received out of it. Waterfall plots are interesting as an approach, but I'm also interested in musical fidelity, I wonder if a few simultaneous tones could help?
I have calibrated measurement microphones, oscilloscopes, impedance jigs etc....
The thought came about for three reasons, firstly because engineering texts mention cabinet resonances and measure how this impacts on the total sound generation form the speaker, I feel this is documented very well. Whilst some measurements for noise 'back' out of a cone are given I haven't seen methodical testing.
Secondly, if you eve look at how measured impedance changes as you move a speaker from free air to different enclosures this is interesting in itself (a measurement I will show)
The final reason is a potential commercial application that I'll have to keep to myself!!
I'll put up some photos of test igs when they're built and ready to go, probably in the new year!
Does anyone have any thoughts on a reference driver(s) to use? It may be interesting to see how cone material/mass effects this, so maybe we need a few?
I'm thinking something like SB acoustics gives me options of aluminium, paper and carbon in similar frames?
I have calibrated measurement microphones, oscilloscopes, impedance jigs etc....
The thought came about for three reasons, firstly because engineering texts mention cabinet resonances and measure how this impacts on the total sound generation form the speaker, I feel this is documented very well. Whilst some measurements for noise 'back' out of a cone are given I haven't seen methodical testing.
Secondly, if you eve look at how measured impedance changes as you move a speaker from free air to different enclosures this is interesting in itself (a measurement I will show)
The final reason is a potential commercial application that I'll have to keep to myself!!
I'll put up some photos of test igs when they're built and ready to go, probably in the new year!
Does anyone have any thoughts on a reference driver(s) to use? It may be interesting to see how cone material/mass effects this, so maybe we need a few?
I'm thinking something like SB acoustics gives me options of aluminium, paper and carbon in similar frames?
Easy test rig to test if woofer cones have difference on the leakage. Could be done like so:
Use your bluetooth speaker as sound source inside a test box. Make the test box with detachable frontpanel to accommodate various drivers easily. Hook the test box driver to an amplifier that is powered on, this will control the cone like it would be controlled in real situation. Then play the bluetooth speaker and listen / measure what comes out.
You could use what ever drivers you have at hand. If there is meaningful difference / leakage, you could purchase few more.
But, you have to realize there is nothing you can do to a driver to reduce the leakage without changing the parameters of the driver. For this reason, only thing one can do to affect leakage is to design the enclosure so that the leakage is minimized, in which case any driver is as good for testing than any other. If some driver had particularly bad leakage, it would not be interesting/popular choise for a speaker project anyway. People like paper cones, metal cones, whatever cones, so I suspect they all work similarly ok.
Use your bluetooth speaker as sound source inside a test box. Make the test box with detachable frontpanel to accommodate various drivers easily. Hook the test box driver to an amplifier that is powered on, this will control the cone like it would be controlled in real situation. Then play the bluetooth speaker and listen / measure what comes out.
You could use what ever drivers you have at hand. If there is meaningful difference / leakage, you could purchase few more.
But, you have to realize there is nothing you can do to a driver to reduce the leakage without changing the parameters of the driver. For this reason, only thing one can do to affect leakage is to design the enclosure so that the leakage is minimized, in which case any driver is as good for testing than any other. If some driver had particularly bad leakage, it would not be interesting/popular choise for a speaker project anyway. People like paper cones, metal cones, whatever cones, so I suspect they all work similarly ok.
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If you replied to my statement concerning the status quo of speakers, that wasn't limited only to expertise of box enclosure speakers.
You can apply that to dipole speakers, to electrostats or to magnetostats, just to any kind of electromechanical speaker system that exists.
The problems with efficiency, tonality, construction of the speaker system itself may vary, but in the end the goal is the same for all types of speaker: a natural, realistic, flat response of high efficiency.
The hurdles to achieve that are for the exotic types not easier to jump over, the exact opposite is the case.
Well, red my own text and it feels negative 😀 my intent was to provide some thoughts where there might be some value to be found and where not so much, but of course I havent done anything else than thought experiments on the issue so never know what you find in the process! Mythbusting at least.
Well, see those texts as a status quo on audio speakers. If you give them a positive or negative rating, thats just mixing it up with morality. Some things are good, others are bad. Its just a belief system.
A doctor tells you a diagnosis, whether you interpret it this or that way, its up to you.
What I was trying to aim in the methods of engineering is, that all those measurement ways may be a powerfull worktool for developing speakers, but we haven't made such big progress since decades as the marketing want us to believe.
Now we have (in the majority of the market) relative less efficient speakers with a maximum of driver chassis and complexity, and its up to you, whether thats good or bad. At least they match with the majority of power amps. To me, they are one of the very few branches of audio where nearly everybody can put together such a system with the help of audio analyzer systems, throw it on the market and make a good living out of it, because its so easy to do so. Everybody knows the Thiele Small parameters of a chassis, can mix it with others on the computer and voila, here is the optimum box enclosure to match your speakers. Thats what people do, and thats how they make big money in that field of "engineering". Easy as pie today. The ingredients of modern speakers in the $$$$$ region are often cheap ferrite chassis and even cheaper crossover parts.
A doctor tells you a diagnosis, whether you interpret it this or that way, its up to you.
What I was trying to aim in the methods of engineering is, that all those measurement ways may be a powerfull worktool for developing speakers, but we haven't made such big progress since decades as the marketing want us to believe.
Now we have (in the majority of the market) relative less efficient speakers with a maximum of driver chassis and complexity, and its up to you, whether thats good or bad. At least they match with the majority of power amps. To me, they are one of the very few branches of audio where nearly everybody can put together such a system with the help of audio analyzer systems, throw it on the market and make a good living out of it, because its so easy to do so. Everybody knows the Thiele Small parameters of a chassis, can mix it with others on the computer and voila, here is the optimum box enclosure to match your speakers. Thats what people do, and thats how they make big money in that field of "engineering". Easy as pie today. The ingredients of modern speakers in the $$$$$ region are often cheap ferrite chassis and even cheaper crossover parts.
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I sense a leaning toward something you can sell. I'm pretty sure no one would pay money for either of the two concoctions I've created, no matter how they sound. I enjoy listening to them, my wife accepts them and that's what matters.
I think part of DIY is that it doesnt have to fit through a "viable commercial product" window. While it may be amusing to accommodate that and dream, I think it's restrictive.
For all anyone knows, that factor may be the "no big progress" root. Something that sounds the best could be this horribly disfigured entity that no one would have in their home - except someone that only cared about how it sounds.
So we can engineer our *sses off to try and squeeze the best sound out of an aesthetically acceptable shape (box), but I think there's an asymptote to how far you can go, with driver arrangement on a baffle, rounded over edges, meta cabinet materials, internal bracing, curved sided containers.
Drop the idea of sales, then see what you can do. That's freedom in DIY.
I think part of DIY is that it doesnt have to fit through a "viable commercial product" window. While it may be amusing to accommodate that and dream, I think it's restrictive.
For all anyone knows, that factor may be the "no big progress" root. Something that sounds the best could be this horribly disfigured entity that no one would have in their home - except someone that only cared about how it sounds.
So we can engineer our *sses off to try and squeeze the best sound out of an aesthetically acceptable shape (box), but I think there's an asymptote to how far you can go, with driver arrangement on a baffle, rounded over edges, meta cabinet materials, internal bracing, curved sided containers.
Drop the idea of sales, then see what you can do. That's freedom in DIY.
Yes, one can build a loudspeaker set that would challenge the best of monitors (flat response) that are out there. Just lately I've simmed-up a three-way that will go from a low F3 of appx.13 hertz to an upper range of 23K hertz plus or minus 2 DB...but the caveat is 1.36 meters high, 1.1 meter deep and 892mm wide....with an appropriate weight to go along with it...a wholly unacceptable "marketable concept". "Artsy" looking, WAF types do NOT make for great sound. The flat accurate "Monitor sound" should be our goals, not catering to the "tweaked" sounds...if us all fell for that, we'd have long since made one-note boom-boom hip-hop sounding stuff...or whatever is " in fashion".
If the music is going to sound mediocre, nothing will discover it as such faster than a good monitor.
----------------------------------------------------------------------Rick.....
If the music is going to sound mediocre, nothing will discover it as such faster than a good monitor.
----------------------------------------------------------------------Rick.....
So you want a monitor box (like the ones in the recording studios) for use at home.
Lets face it: most normal records sound just ordinary.
And as you state, those monitor speakers will reveal that with ease.
So what kind of music source will you play at home to be excited, to feel some enjoyment at all when you listen to recorded music?
And I would be interested, what efficiency has your design monitor speaker that you simulated lately? You wrote all about the flat response, super perfect, measurements of the box but what efficiency? Thats the most important question, because with a low efficiency, there would be need for the big amps that doesn't sound quite good as the small ones.
I don't want to audition music at home with a monitor box. Just because its most often not ideal. The rooms at home aren't studio rooms, damped and optimized for audio. Most people listen to music in living rooms. Suboptimal for monitor boxes, as you would never have that flat response they are trimmed to have in the studios.
I'm not going to buy those super records on LP or hyper- expensive master tapes just to hear good music with enjoyment. I wan't just the ordinary music to sound excellent, with rythm, with feeling, much emotions and excitement. And for that reason, I don't want studio monitors in my living room. As most people won't like them.
Lets face it: most normal records sound just ordinary.
And as you state, those monitor speakers will reveal that with ease.
So what kind of music source will you play at home to be excited, to feel some enjoyment at all when you listen to recorded music?
And I would be interested, what efficiency has your design monitor speaker that you simulated lately? You wrote all about the flat response, super perfect, measurements of the box but what efficiency? Thats the most important question, because with a low efficiency, there would be need for the big amps that doesn't sound quite good as the small ones.
I don't want to audition music at home with a monitor box. Just because its most often not ideal. The rooms at home aren't studio rooms, damped and optimized for audio. Most people listen to music in living rooms. Suboptimal for monitor boxes, as you would never have that flat response they are trimmed to have in the studios.
I'm not going to buy those super records on LP or hyper- expensive master tapes just to hear good music with enjoyment. I wan't just the ordinary music to sound excellent, with rythm, with feeling, much emotions and excitement. And for that reason, I don't want studio monitors in my living room. As most people won't like them.
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Well that's it. This will be my last post on the forums of DIY audio.
Bernie88, thank you for threadjacking and turning this away from a positive exercise to build knowledge in the DIY community and into your soapbox to spout your latest on ideas. You speak with the greatest of authority about things of which you know little in a forum that had nothing to do with the angenda you have set out.
I don't have the time to waste with you breaking down your nonsensical arguements, nor the constant foolery I see on this forum.
I will post a different goodbye somewhere else.
Bernie88, thank you for threadjacking and turning this away from a positive exercise to build knowledge in the DIY community and into your soapbox to spout your latest on ideas. You speak with the greatest of authority about things of which you know little in a forum that had nothing to do with the angenda you have set out.
I don't have the time to waste with you breaking down your nonsensical arguements, nor the constant foolery I see on this forum.
I will post a different goodbye somewhere else.
