Volume of room not just reflections
I agree with this.
The room has a huge effect on the sound, done deal we all accept this.
But your point that the volume of room not just reflections acoustic signature of the room is also important.
I have had a similar experience when moving a system (50 litre three way, passive, sealed box spks) from a small but well designed studio, to a large state of the art high ceiling room and then setting it up outdoors with a 50 meter extension cable to get away from all objects.
The perceived dynamic range increased dramatically from small to out door ie the jump factor increased when the volume settings remained the same.
I agree with this.
The room has a huge effect on the sound, done deal we all accept this.
But your point that the volume of room not just reflections acoustic signature of the room is also important.
I have had a similar experience when moving a system (50 litre three way, passive, sealed box spks) from a small but well designed studio, to a large state of the art high ceiling room and then setting it up outdoors with a 50 meter extension cable to get away from all objects.
The perceived dynamic range increased dramatically from small to out door ie the jump factor increased when the volume settings remained the same.
Reduce cone excursion and you reduce all forms of distortion
Here here!
If you want to reduce your mid-range distortion by a factor of 8(!) .... Add a subwoofer.
Example, take a two way sealed box monitor (passive or active) with a crossover around 2KHz.
All cones / domes follow a cubed rule of excursion Vs frequency for each octave lower or higher.
For example if a bass mid cone is moving plus / minus 4mm in order to produce a 60Hz tone at 96dB SPL, the cone travel reduces to plus / minus 0.5mm in order to produce a 120Hz tone.... Also the came cone will have to travel plus / minus 32mm (!) in order to produce a 30Hz tone... Rather exreme Xmax!
Reducing cone travel is vital as all forms of distortion track pretty much in line with cone travel.
There is some debate as to the exact tracking of cone movement Vs distortion but its an accepted fact that reducing cone travel reduces distortion.
IMD, thermal distortion (power compression) and APE's are the main culprits and they all reduce closely in line with cone travel.
Adding a sub with a good active crossover at around 80Hz to 120Hz is the single most effective way to reduce all distortions from the bass mid driver.
Here here!
If you want to reduce your mid-range distortion by a factor of 8(!) .... Add a subwoofer.
Example, take a two way sealed box monitor (passive or active) with a crossover around 2KHz.
All cones / domes follow a cubed rule of excursion Vs frequency for each octave lower or higher.
For example if a bass mid cone is moving plus / minus 4mm in order to produce a 60Hz tone at 96dB SPL, the cone travel reduces to plus / minus 0.5mm in order to produce a 120Hz tone.... Also the came cone will have to travel plus / minus 32mm (!) in order to produce a 30Hz tone... Rather exreme Xmax!
Reducing cone travel is vital as all forms of distortion track pretty much in line with cone travel.
There is some debate as to the exact tracking of cone movement Vs distortion but its an accepted fact that reducing cone travel reduces distortion.
IMD, thermal distortion (power compression) and APE's are the main culprits and they all reduce closely in line with cone travel.
Adding a sub with a good active crossover at around 80Hz to 120Hz is the single most effective way to reduce all distortions from the bass mid driver.
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well you can lay the FRs over each other and they look to be within "approx" 1/2 db of each other from 1khz to 15khz except for a wiggle on the foil only ribbon where there is a sharp dip at about 5khz returning to level by about 5.4khz and is about 2 db depth. Also the foil only ribbon is about 1.5 db higher output by time we get to 20khz. You can see some energy storage at that 5khz dip but the tail is short ( 30 db down by 2 ms) The other ribbons are laminated constructions and are smooth through this area.
I cant hear much past 15k and that 5k dip seems too short and decays so fast its hard to believe thats the difference. So far the only thing I can find that stands out is that the Foil only version is about 2 db more sensitive than the others. Could the sensitivity have something to do with the precieved difference?(yes they are EQed to same levels in system). I realize that 5k area can be critical but as said its so small and sharp.
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It's my understanding that it's not inconceivable that frequencies above where your hearing rolls off can still have an effect on perception
sorry if this seems sidebar
if reducing excursion reduces distortion. then what's up all the attempts at operating tweeter's and compression driver's at lower frequencies in an attempt to get better matched directivity between adjacent frequency band drivers?
doesn't that sort of create a design trade off problem; raise the x-over frequency point to reduce excursion and consequently distortion or lower it in order to get the directivity better?
if reducing excursion reduces distortion. then what's up all the attempts at operating tweeter's and compression driver's at lower frequencies in an attempt to get better matched directivity between adjacent frequency band drivers?
doesn't that sort of create a design trade off problem; raise the x-over frequency point to reduce excursion and consequently distortion or lower it in order to get the directivity better?
lowmass i would love to hear your drivers personally.
i indeed think that the"foil only" 's better high frequency sensitivity is key to the "perceivable" difference.
this also speaks to the whole "peaks" are more detectable then "dips" philosophy.
i indeed think that the"foil only" 's better high frequency sensitivity is key to the "perceivable" difference.
this also speaks to the whole "peaks" are more detectable then "dips" philosophy.
The higher bandwidth would also mean it would have a better phase response in the pass band, I would not like to say whether this is audible
My experience is linearizing phase is more important than the bandwidth. But we also need to understand that phase lag starts from the recording mic...
Interesting, yea there is some difference in the CSD between the laminated and the foil only versions as well. I wonder how audible though as they both show everything down by about 2 ms.
I would love to send you and maybe a few others a pair when the time is right. At the moment I think we are about done with reliability testing and all looks good. However the patent is not finished yet. Once that is submitted then I can let the cat out of the bag.
Shrewd observation...Variables are all trade offs
This is where the art takes over from the science... Or at least balances it out.
It comes down to judging the benefits of each variable.
For example adding sub(s):
(1) Excursion Vs bandwidth, you benefit from reduced lower distortion with lower excursion but you "suffer" from an additional crossover point and the associated phase / matching issues. Plus the additional cost / floor space WAF etc of a sub-woofer (s).
Adding subs does bring a lot of other benefits though, esp muiltiple subs as detailed in the work done by Dr Geddes, credit where credit is due... His work on this subject is superb.
Other variables I often stress over are :
(2) Centre to centre driver spacing Vs crossover point.
(3) Sd (more is better as it reduces excursion) Vs power bandwidth / off axis response... Small drivers = better / more even room coverage... Large drivers reduced coverage. Polar response graphs are important here.
(4) Mms / Bl. Low Mms with high Bl = Higher efficiency & better cone control (also lower thermal distortion as the voice coil is not having to dissipate as much power as heat) but less low end extension.
(5) Line array Vs point source.... Too many pro's and cons to go into here!
So, reducing excursion is easy to achieve by:
Adding subs(s)
Increasing driver size (Sd)
Adding more drivers ie MTM, line array or even panels.
Increasing driver efficiency with horns is also good as it reduces thermal distortion and reduces excursion.
Take an 8 inch driver with a sensitivity of 88dB with 1 watt at 1 meter.
1 watt = 88dB.
2 watt = 91dB.
4 watt = 94dB
8 watt = 97dB.
16 watt = 100dB
32 watt = 103dB
64 watt = 106dB
128 watt = 109dB
256 watt = 112dB
If one requires peak SPL's of say 100dB (average SPL might be around 75dB to 80dB) you need to use 16 watts of power.
If you add a large front loaded horn you might add around 10dB of driver sensitivity (efficiency remains the same) so one would only require around 1.6 watts. This has major driver distortion reduction benefits.
The above assumes point source loudspeaker at 1 meter listening distance, so deduct 6dB for listening at 2 meters 12dB for listening at 4 meters etc. as point sources diminish at 6dB per doubling of distance.
Line arrays only reduce by 3dB per doubling of distance.... This is one major advantage of line arrays.
This is where the art takes over from the science... Or at least balances it out.
It comes down to judging the benefits of each variable.
For example adding sub(s):
(1) Excursion Vs bandwidth, you benefit from reduced lower distortion with lower excursion but you "suffer" from an additional crossover point and the associated phase / matching issues. Plus the additional cost / floor space WAF etc of a sub-woofer (s).
Adding subs does bring a lot of other benefits though, esp muiltiple subs as detailed in the work done by Dr Geddes, credit where credit is due... His work on this subject is superb.
Other variables I often stress over are :
(2) Centre to centre driver spacing Vs crossover point.
(3) Sd (more is better as it reduces excursion) Vs power bandwidth / off axis response... Small drivers = better / more even room coverage... Large drivers reduced coverage. Polar response graphs are important here.
(4) Mms / Bl. Low Mms with high Bl = Higher efficiency & better cone control (also lower thermal distortion as the voice coil is not having to dissipate as much power as heat) but less low end extension.
(5) Line array Vs point source.... Too many pro's and cons to go into here!
So, reducing excursion is easy to achieve by:
Adding subs(s)
Increasing driver size (Sd)
Adding more drivers ie MTM, line array or even panels.
Increasing driver efficiency with horns is also good as it reduces thermal distortion and reduces excursion.
Take an 8 inch driver with a sensitivity of 88dB with 1 watt at 1 meter.
1 watt = 88dB.
2 watt = 91dB.
4 watt = 94dB
8 watt = 97dB.
16 watt = 100dB
32 watt = 103dB
64 watt = 106dB
128 watt = 109dB
256 watt = 112dB
If one requires peak SPL's of say 100dB (average SPL might be around 75dB to 80dB) you need to use 16 watts of power.
If you add a large front loaded horn you might add around 10dB of driver sensitivity (efficiency remains the same) so one would only require around 1.6 watts. This has major driver distortion reduction benefits.
The above assumes point source loudspeaker at 1 meter listening distance, so deduct 6dB for listening at 2 meters 12dB for listening at 4 meters etc. as point sources diminish at 6dB per doubling of distance.
Line arrays only reduce by 3dB per doubling of distance.... This is one major advantage of line arrays.
This is why I decided to due further development of ribbons. I always found myself trying to take the dome tweeter lower than it could handle. years ago it seemed to me that if we could overcome the issues of small ribbon lower freq control and power handling , that they could fill the gap better than a small dome and we can avoid the cone breakup region better.
Yes there will always be the vertical dispersion argument with ribbons BUT in my experience I will gladly trade what I see as a small issue with vertical dispersion (within reason whatever that is 🙂 ) for what to my ears gives a big benefit everywhere else, ie a lower tweeter crossover point.
To my ears the difference between a 1 khz and a 2 khz crossover makes a useful difference especially to the average DIY group
Beyma TPL reference
Fingers crossed for you Lowmass... Hope your ribbon design works and you can get solid IP protection.
My I suggest you buy a pair of Beyma TPL 150 (no horn required) but remove the TPL back and felt dampening and load them in a tapered asymmetrical 2.5 litre sealed box with approx 1.5 litres of Twaron (or "Angel Hair) and heavy cabinet wall dampening.
This loading / cabinet construction lifts the performance from very good value to world class... almost on par with the silly money Plasma HF units.
This would be a true reference for you to judge your ribbons against.
My own experience with the TPL's is they sound best above 2KHz or so,but they start to sound congested and glassy if asked to play high SPL's below 2K.
Its frequency response still looks good on paper, but its CSD below 2KHz gets ugly at real world SPL,s below 2K.
Fingers crossed for you Lowmass... Hope your ribbon design works and you can get solid IP protection.
My I suggest you buy a pair of Beyma TPL 150 (no horn required) but remove the TPL back and felt dampening and load them in a tapered asymmetrical 2.5 litre sealed box with approx 1.5 litres of Twaron (or "Angel Hair) and heavy cabinet wall dampening.
This loading / cabinet construction lifts the performance from very good value to world class... almost on par with the silly money Plasma HF units.
This would be a true reference for you to judge your ribbons against.
My own experience with the TPL's is they sound best above 2KHz or so,but they start to sound congested and glassy if asked to play high SPL's below 2K.
Its frequency response still looks good on paper, but its CSD below 2KHz gets ugly at real world SPL,s below 2K.
vertical dispersion not important.
PS
Totally with on you on the vertical dispersion issue... Its really a small detail and just about the least important aspect of a drivers performance.
PS
Totally with on you on the vertical dispersion issue... Its really a small detail and just about the least important aspect of a drivers performance.
Thanks and yes this is the issue I see with that type of driver. Potential for truly great perf BUT the mechanical property of those small folds will always be an issue trying to get to 1khz in a small package. And agree totally on the chamber size/shape/damp! Critical to great perf on thin light diaphragms. I think I spent months on the damn box alone Ha!
At present a traditionally constructed free swinging ribbon the same size of what I am developing will see distortion, particularly 3rd harm start to rise sharply below about 1.5 khz even at only 90 db. The design I have now with a first order filter at 800 hz shows approx 0.25% at 90db down to 1 khz and is at 0.8% at 105 db. As far as I know there are no similar sized free swinging ribbons that come close to this.
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This sounds really promising!
Congratulations Lowmass you are already ahead of the pack and I am sure you will advance even further with fine tuning and material / component changes.
3D is advancing at an astonishing rate and its now possible to print metal and carbon / hybrid components. Lots of potential for thin film / alloy foils. Also one can print driver chassis and face plates which have incredible strength.
All these can avoid / delay tooling costs .... You can get into production without spending too much $$... Early sales and positive reviews means that when you negociate with investors or banks you are in a much stronger postion.... You keep control!
Last suggestion... Delay publication of your patent application as long as possible... There are ways to do this that a good patent lawyer can help with.... If you have a game changer, the second the patent goes public big money will be spent to circumnavigate your patent.
All the best.
Alex.
Congratulations Lowmass you are already ahead of the pack and I am sure you will advance even further with fine tuning and material / component changes.
3D is advancing at an astonishing rate and its now possible to print metal and carbon / hybrid components. Lots of potential for thin film / alloy foils. Also one can print driver chassis and face plates which have incredible strength.
All these can avoid / delay tooling costs .... You can get into production without spending too much $$... Early sales and positive reviews means that when you negociate with investors or banks you are in a much stronger postion.... You keep control!
Last suggestion... Delay publication of your patent application as long as possible... There are ways to do this that a good patent lawyer can help with.... If you have a game changer, the second the patent goes public big money will be spent to circumnavigate your patent.
All the best.
Alex.
two plasma tweeters.
I have only ever heard two plasma tweeters, Lanche in a dealers and Acapella at a show.
Both in were in different rooms and with different electronics so impossible to make a judgement between which is best....
But, they both had a totally life like top end which was addictive, so natural it put a smile on my face.
The "pimped up" Beyma TPL got close.... If I had to put a number on it, gut feel 80% as good s the plasmas.
The Beyma is the best top end I have heard apart from the plasma's.
I have heard a lot of electrostactic / maggies / panels and various other AMT drivers and ribbons but they have always been with passive crossovers / average electronics or at shows.... So never been able to get them into my reference system at home.
The Beyma makes cymbals come to life without sounding glassy or squashed ... Sorry about the descriptions but its hard to describe!
I have only ever heard two plasma tweeters, Lanche in a dealers and Acapella at a show.
Both in were in different rooms and with different electronics so impossible to make a judgement between which is best....
But, they both had a totally life like top end which was addictive, so natural it put a smile on my face.
The "pimped up" Beyma TPL got close.... If I had to put a number on it, gut feel 80% as good s the plasmas.
The Beyma is the best top end I have heard apart from the plasma's.
I have heard a lot of electrostactic / maggies / panels and various other AMT drivers and ribbons but they have always been with passive crossovers / average electronics or at shows.... So never been able to get them into my reference system at home.
The Beyma makes cymbals come to life without sounding glassy or squashed ... Sorry about the descriptions but its hard to describe!
plasma tweeter update
The Once and Future Tweeter | PS Audio
This link is a good source of info on plasma tweeters... Updates to 2016 RMAF.
The Once and Future Tweeter | PS Audio
This link is a good source of info on plasma tweeters... Updates to 2016 RMAF.
What is your opinion on the performance of the Beymas above 10K? Many people have said that they will do better with some help in the highs
I have not heard plasma except the green blue cloud around the ocasional transformer bomb at the substation near our ocal salt mine.
Joking aside I suspect nothing is going to do the treeble quite like the flame and I also suspect the amt's fundamental perf is also going to be a tough act to follow. its simply got a serious advantage in a couple areas.
I do believe I have a game changing addintion to the world of ribbon and I hear ya on the protection thing. We are tearing our hair out trying to word the document to exclude others but as you seem to be aware there often a way around these things. Always best if you get in first on a fundamental and elegantly simple way but no garontees in this word.
To be honest what actaully excites me is bringing this tech to a lower price point.I suspect could pump it up and go big BUT Ive always been facinated most when a simple and relativly (wahtever that is) afordable transducer outperforms the rediculously expensive.
I have come from ashes and have gotten this far from having to find a cheaper ways to do what has traditionaly been expensive and complex. I realy cannot claim genious, more like years of passionate hands on tends to stumble on a good idea now and then.
Joking aside I suspect nothing is going to do the treeble quite like the flame and I also suspect the amt's fundamental perf is also going to be a tough act to follow. its simply got a serious advantage in a couple areas.
I do believe I have a game changing addintion to the world of ribbon and I hear ya on the protection thing. We are tearing our hair out trying to word the document to exclude others but as you seem to be aware there often a way around these things. Always best if you get in first on a fundamental and elegantly simple way but no garontees in this word.
To be honest what actaully excites me is bringing this tech to a lower price point.I suspect could pump it up and go big BUT Ive always been facinated most when a simple and relativly (wahtever that is) afordable transducer outperforms the rediculously expensive.
I have come from ashes and have gotten this far from having to find a cheaper ways to do what has traditionaly been expensive and complex. I realy cannot claim genious, more like years of passionate hands on tends to stumble on a good idea now and then.