Hi,
this is my small panel, measured in a anechoic chamber using Monkey Forest and a B&K-Mic-capsule.
Input power was ~50W, which translated to a SPL of ~122dB@4m!
It´s the point just before the membrane touches the stators.
The panel is used at freqs >250Hz.
IM-distortion tests ended with trying to find a ´special´ 2-tone combination where IM-artefacts became just visible with ~-70dB.
At normal listening levels the panel is virtually distortion-free.
A very deciding point is the quality of the amp and the audio transformer. Most of the distortion stems from the tranny and a unstable amp can reach easily much higher distortion levels than a well executed panel.
This is very different to the rather high distortions of ribbons and magnetostats. The ESL is pure and clean up to earsplitting levels as no other loudspeaker principle.
jauu
Calvin
this is my small panel, measured in a anechoic chamber using Monkey Forest and a B&K-Mic-capsule.
Input power was ~50W, which translated to a SPL of ~122dB@4m!
It´s the point just before the membrane touches the stators.
The panel is used at freqs >250Hz.
An externally hosted image should be here but it was not working when we last tested it.
IM-distortion tests ended with trying to find a ´special´ 2-tone combination where IM-artefacts became just visible with ~-70dB.
At normal listening levels the panel is virtually distortion-free.
A very deciding point is the quality of the amp and the audio transformer. Most of the distortion stems from the tranny and a unstable amp can reach easily much higher distortion levels than a well executed panel.
This is very different to the rather high distortions of ribbons and magnetostats. The ESL is pure and clean up to earsplitting levels as no other loudspeaker principle.
jauu
Calvin
I have recently fired up my new wire panels. THD was ~0,5% from 100 Hz to around 500Hz , ~0.1% from around 500 Hz and up. At some frequencies it was as low as 0.02%. The signal level was around 70% of full output power . However , I meeasured in noisy room(with computer on) , so results may improve. The quality of transformers is not the best, having THD up to ~0.1-0.2% at low frequencies.
Panels are disconnected now, since I have to complete electronics and order better transformers , so I cannot repeat measurements. Here is the frequency response (not the best , again measured in my living room).
I will post more detalailed measurements when panels are finished completely.
Panels are disconnected now, since I have to complete electronics and order better transformers , so I cannot repeat measurements. Here is the frequency response (not the best , again measured in my living room).
I will post more detalailed measurements when panels are finished completely.
Attachments
Hi,
@Mor
there are pics and descriptions of the panel in earlier threads.
@Wayne
No I didn´t say that and didn´t even thought that there was any room left for such an interpretation.
There are of course many who prefer a rather distorted signal (especially with K2) over a clean signal. But thats a matter of taste. Objectively the signal quality of a well executed ESL (in the midhigh frequency range to be precise) is the best I´ve seen in any loudspeaker.
@bear
uups I cited myself wrong
The measured value is 110dB@4m, which translates to 122dB@1m for a global distribution character. For the panel the SPL value at a distance of 4m is higher than at 1m because of the cylindrical distribution character. If You recalculate the SPL@4m to the value @1m for a global distribution character, You have to add 12dB, hence 122dB.
In praxis the global player won´t loose 12dB with a quadrupling of distance because of a not ideal global distribution and room acoustics, but on the other hand it suffers from thermal compression, spider progression related compression and BL-nonlinearities which add up to 2-3dB. A ESL-panel dose not suffer from compression until the diaphragm hits the stators. The SPL over input power curve is very linear. So, 110dB@4m is the real measured value, 122dB@1m is the calculated equivalent value for a global distribution character.
The curves are K2,3,4 and 5. K5 can just be seen as a very small peak around 4kHz and -75dB.
Measured with a MB550 mic-capsule You roughly can add 0.1% to 0.2% to these distortion values and even higher values when using cheaper mics. Even though the used B&K capsule came fresh from testing and calibrating by B&K, I don´t know the distortion figures for this capsule. But it should be kept in mind that the complete measurement setup adds distortions of its own which could actually be the major part of overall distortion in this measurement at these high SPL levels.
´Small´ means 25x125cm (~10"x 49").
jauu
Calvin
@Mor
there are pics and descriptions of the panel in earlier threads.
@Wayne
No I didn´t say that and didn´t even thought that there was any room left for such an interpretation.
There are of course many who prefer a rather distorted signal (especially with K2) over a clean signal. But thats a matter of taste. Objectively the signal quality of a well executed ESL (in the midhigh frequency range to be precise) is the best I´ve seen in any loudspeaker.@bear
uups I cited myself wrong
The measured value is 110dB@4m, which translates to 122dB@1m for a global distribution character. For the panel the SPL value at a distance of 4m is higher than at 1m because of the cylindrical distribution character. If You recalculate the SPL@4m to the value @1m for a global distribution character, You have to add 12dB, hence 122dB.
In praxis the global player won´t loose 12dB with a quadrupling of distance because of a not ideal global distribution and room acoustics, but on the other hand it suffers from thermal compression, spider progression related compression and BL-nonlinearities which add up to 2-3dB. A ESL-panel dose not suffer from compression until the diaphragm hits the stators. The SPL over input power curve is very linear. So, 110dB@4m is the real measured value, 122dB@1m is the calculated equivalent value for a global distribution character.
The curves are K2,3,4 and 5. K5 can just be seen as a very small peak around 4kHz and -75dB.
Measured with a MB550 mic-capsule You roughly can add 0.1% to 0.2% to these distortion values and even higher values when using cheaper mics. Even though the used B&K capsule came fresh from testing and calibrating by B&K, I don´t know the distortion figures for this capsule. But it should be kept in mind that the complete measurement setup adds distortions of its own which could actually be the major part of overall distortion in this measurement at these high SPL levels.
´Small´ means 25x125cm (~10"x 49").
jauu
Calvin
Calvin said:Hi,
@Mor
there are pics and descriptions of the panel in earlier threads.
@Wayne
No I didn´t say that and didn´t even thought that there was any room left for such an interpretation.
@bear
uups I cited myself wrong
The measured value is 110dB@4m, which translates to 122dB@1m for a global distribution character. For the panel the SPL value at a distance of 4m is higher than at 1m because of the cylindrical distribution character. If You recalculate the SPL@4m to the value @1m for a global distribution character, You have to add 12dB, hence 122dB.
In praxis the global player won´t loose 12dB with a quadrupling of distance because of a not ideal global distribution and room acoustics, but on the other hand it suffers from thermal compression, spider progression related compression and BL-nonlinearities which add up to 2-3dB. A ESL-panel dose not suffer from compression until the diaphragm hits the stators. The SPL over input power curve is very linear. So, 110dB@4m is the real measured value, 122dB@1m is the calculated equivalent value for a global distribution character.
The curves are K2,3,4 and 5. K5 can just be seen as a very small peak around 4kHz and -75dB.
Measured with a MB550 mic-capsule You roughly can add 0.1% to 0.2% to these distortion values and even higher values when using cheaper mics. Even though the used B&K capsule came fresh from testing and calibrating by B&K, I don´t know the distortion figures for this capsule. But it should be kept in mind that the complete measurement setup adds distortions of its own which could actually be the major part of overall distortion in this measurement at these high SPL levels.
´Small´ means 25x125cm (~10"x 49").
jauu
Calvin
Calvin ,
Where are the pics ?...........................................
Are you saying your speaker is 122db@ 1w/1M or @ 50 watts
Hi,
@Mor
I´m doing only hybrid-ESLs, so Yes, I use a dynamic bass. It have been 8x 7" drivers per side in the first models and will be just 6 drivers in future, working in a dipole casing. Crossover freq is ~250Hz
With the large panel it has been 8x 8" drivers in dipole casings.
It will be 8x7" in a dipole casing with a crossover of ~150-180Hz and a CB-woofer below 50hz featuring 2x18" verylongthrow drivers.
@wayne
here´s a pic of the old ESEL (german for donkey, but I prefer ´Entity of Superior Electrostatic Loudspeaking´) which was DIY
http://www.diyaudio.com/forums/showthread.php?s=&threadid=95324 ...and here are pics of the actual models which have become commercial.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=124282
The new models which will be presented at Munic HighEnd2009 will be smaller in height (160cm the big one and 135cm the small one instead of 195cm as it is now), the casings will be manufactured from magnesium and the big one will come with the big subwoofer in a concrete globe casing.
What I tried to say was that a typical loudspeaker (which is assumed to have a global distribution character) will produce 110dB@4m if it produces 122dB@1m (regardless of how much power is needed for this SPL) because the SPL drops by 6dB per doubling of measuring distance, starting with the highest value close to the surface of the membrane.
The panel produces less than 110dB@1m because the SPL drops when You approach the cylindrical line source. You have to understand that a cylindrical distribution pattern behaves very different to a global pattern with regard to SPL over distance. The SPL rises from the surface of the membrane to a distance of ~3-4m (with panels of more than 1m height). Above this distance the SPL starts to drop but with just 3dB per doubling of measuring distance.
You can easily hear this character in a large, long room, where the cylindrical pattern shows a much more uniform SPL-level than a global pattern.
The panel produces 110dB@4m with an input power of app. 50W. Its not easy to state a real efficiency because of the varying impedance of the speaker. So the 50W would mean equivalent 50W@8Ohms.
jauu
Calvin
@Mor
I´m doing only hybrid-ESLs, so Yes, I use a dynamic bass. It have been 8x 7" drivers per side in the first models and will be just 6 drivers in future, working in a dipole casing. Crossover freq is ~250Hz
With the large panel it has been 8x 8" drivers in dipole casings.
It will be 8x7" in a dipole casing with a crossover of ~150-180Hz and a CB-woofer below 50hz featuring 2x18" verylongthrow drivers.
@wayne
here´s a pic of the old ESEL (german for donkey, but I prefer ´Entity of Superior Electrostatic Loudspeaking´) which was DIY
http://www.diyaudio.com/forums/showthread.php?s=&threadid=95324 ...and here are pics of the actual models which have become commercial.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=124282
The new models which will be presented at Munic HighEnd2009 will be smaller in height (160cm the big one and 135cm the small one instead of 195cm as it is now), the casings will be manufactured from magnesium and the big one will come with the big subwoofer in a concrete globe casing.
What I tried to say was that a typical loudspeaker (which is assumed to have a global distribution character) will produce 110dB@4m if it produces 122dB@1m (regardless of how much power is needed for this SPL) because the SPL drops by 6dB per doubling of measuring distance, starting with the highest value close to the surface of the membrane.
The panel produces less than 110dB@1m because the SPL drops when You approach the cylindrical line source. You have to understand that a cylindrical distribution pattern behaves very different to a global pattern with regard to SPL over distance. The SPL rises from the surface of the membrane to a distance of ~3-4m (with panels of more than 1m height). Above this distance the SPL starts to drop but with just 3dB per doubling of measuring distance.
You can easily hear this character in a large, long room, where the cylindrical pattern shows a much more uniform SPL-level than a global pattern.
The panel produces 110dB@4m with an input power of app. 50W. Its not easy to state a real efficiency because of the varying impedance of the speaker. So the 50W would mean equivalent 50W@8Ohms.
jauu
Calvin
Hello Calvin ,
Nice looking units , curious about the method you used for testing the efficiency , most use 2.83 V@ 1 M , this was kind of an industry standard used to test and compare differing speakers and there efficiency .
Testing at 4 m is advantageous for a linesource , but not so a point source .... The numbers you quote are indicative of a curved linesource.
Sanders himself have also moved away from using curved Panels .
http://sanderssoundsystems.com/index.php?option=com_content&task=view&id=26&Itemid=30
From the man himself :
http://www.youtube.com/watch?v=Vdf3VA06iSA&feature=related
Nice looking units , curious about the method you used for testing the efficiency , most use 2.83 V@ 1 M , this was kind of an industry standard used to test and compare differing speakers and there efficiency .
Testing at 4 m is advantageous for a linesource , but not so a point source .... The numbers you quote are indicative of a curved linesource.
Sanders himself have also moved away from using curved Panels .
http://sanderssoundsystems.com/index.php?option=com_content&task=view&id=26&Itemid=30
From the man himself :
http://www.youtube.com/watch?v=Vdf3VA06iSA&feature=related
Hi,
Yeah, of course am I talking about the behaviour of a line source. That is what the term ´cylindrical distribution character´ implies!
I normally use 2.83V (for 6Ohms and higher) or 2V (for lower than 6Ohms) measuring voltage. But this shows a problem. 2.83V or 2V are chosen because these voltages produce 1W of power in a 8Ohm resp 4Ohm resistance. Additionally You choose a kind of midpoint in the drivers frequency bandwidth. Since neither impedance nor amplitude response are constant its already difficult with a constant voltage measurement to find the ´real´ efficiency value. Its even worse if You want to find the power efficiency. Where to find the right points of impedance and amplitude for a speaker thats impedance varies widely over frequency??
Since a measuring distance of 1m is disturbed less by room artefacts than a measurement at higher distances and still allows for somehow reasonable measurements of multiway speakers, it has become kind of industry standard. But a line source asks for different measurement setups and so nearfield 10cm and 4m distance are kind of standard for this type of speakers.
Wether You prefer a flat or a curved panel depends on many influencing factors. For a manufacturer ease of manufacturing and costs could be much more decisive factors than anything else.
Both technologies have their merits and their flaws. Some of the advantages hold true in theory and praxis and some just in theory.
The distribution character of curved panels is very narrow already compared to the typical small cone/dome speaker systems. This makes a further increase in directionality imho utterly useless, because the speaker becomes practically unlistenable. There have been measures of such panels that showed a rather ´constant´ amplitude behaviour just over a listening angle of less than 1°. Unless You nail your head fixed every slight movement will show in a different sonic character. The horizontal curvature releaves a bit from the ´positional´ stress, not much, but just enough (the claim of ML of a 30° distribution angle doesn´t hold true..in praxis its maybe 5°). For frequencies with wavelenghts longer than the panel´s width (<1kHz) the shape doesn´t play a role anyway.
Flat panels can be built truely symmetrical, while curved panels introduce a certain asymmetry. This should show in the distortion values and the more clearly with longthrow panels, like Fullrange for eg. But since a ESL is only good when the excursion can be kept below +-0,5mm (+-20mil) there´s no advantage for a flat panel above ~100Hz either. Distortion values are much more affected by other factors and can be extremely low with both kind of panels.
The real advantage of flat panels is the easier manufacturing and the possibility to electrically segment the panel. This is done to control dispersion as well as to reduce the capacitive load on the amplifier. Both techniques are not used by RS. The curved panel is mechanically stronger or can be constructed with lower thickness or without additional bracing. This makes them optically rather more pleasing and transparent.
The real disadvantage of most curved panels -besides beeing more complicated and costly in manufacturing- lies in the fact that nearly each of these builds feature mechanically stretched membranes.
A mechanically stretched membrane needs due time to settle to its stable working point. You need a lot of experience to manufacture the panels so that they reach their final working point precisely and constantely after dozends of hours play at the customers home! Flat membranes can be heat treated which allows for final parameter control at the factory. To my knowledge I am the only one who builds heat treated curved panels (and it is different to the procedure and materials as in RS´s book).
So drawing the line a curved panel is in no way inferior to a flat panel, especially not a non-segmented flat panel. It features better practicability and allows for more transparent optics.
Regarding the Youtube-link and bass for an ESL. Listen to 3min 12-3min14 and compare to the claims made before and after
Wether You use a CB or BR or TML doesn´t matter at all when it comes to crossing over from dynamic bass to ESL-panel.
Neither the distribution character nor the SPL-over-distance behaviour of the two channels match! But this is the prime factor of a seamless integration of the two branches. You need the same (or at least a similar) distribution character for one to two octaves around the crossover frequency. The abrupt change in distribution character is audible no matter how good the crossover is done electrically. This fact has lead to the fairy tale of the impossibility of combining heavy paper cones with lightweight film and the misbelief of Fullrangers beeing the superior electrostats.
If the SPL-over-distance behaviour doesn´t match, then will there be just one distance(!) where the SPL of bass and panel is equal. Approaching the speaker the bass will be too loud and on a greater distance the panel plays louder than the bass.
So a typical thin strip ESL (line source) with a single dynamic bass driver (global distribution) can never be the optimal solution of driver integration. The transistion will always remain audible.
The advantage against the proper solution is compactness, lower effort and less cost.
jauu
Calvin
Yeah, of course am I talking about the behaviour of a line source. That is what the term ´cylindrical distribution character´ implies!
I normally use 2.83V (for 6Ohms and higher) or 2V (for lower than 6Ohms) measuring voltage. But this shows a problem. 2.83V or 2V are chosen because these voltages produce 1W of power in a 8Ohm resp 4Ohm resistance. Additionally You choose a kind of midpoint in the drivers frequency bandwidth. Since neither impedance nor amplitude response are constant its already difficult with a constant voltage measurement to find the ´real´ efficiency value. Its even worse if You want to find the power efficiency. Where to find the right points of impedance and amplitude for a speaker thats impedance varies widely over frequency??
Since a measuring distance of 1m is disturbed less by room artefacts than a measurement at higher distances and still allows for somehow reasonable measurements of multiway speakers, it has become kind of industry standard. But a line source asks for different measurement setups and so nearfield 10cm and 4m distance are kind of standard for this type of speakers.
Wether You prefer a flat or a curved panel depends on many influencing factors. For a manufacturer ease of manufacturing and costs could be much more decisive factors than anything else.
Both technologies have their merits and their flaws. Some of the advantages hold true in theory and praxis and some just in theory.
The distribution character of curved panels is very narrow already compared to the typical small cone/dome speaker systems. This makes a further increase in directionality imho utterly useless, because the speaker becomes practically unlistenable. There have been measures of such panels that showed a rather ´constant´ amplitude behaviour just over a listening angle of less than 1°. Unless You nail your head fixed every slight movement will show in a different sonic character. The horizontal curvature releaves a bit from the ´positional´ stress, not much, but just enough (the claim of ML of a 30° distribution angle doesn´t hold true..in praxis its maybe 5°). For frequencies with wavelenghts longer than the panel´s width (<1kHz) the shape doesn´t play a role anyway.
Flat panels can be built truely symmetrical, while curved panels introduce a certain asymmetry. This should show in the distortion values and the more clearly with longthrow panels, like Fullrange for eg. But since a ESL is only good when the excursion can be kept below +-0,5mm (+-20mil) there´s no advantage for a flat panel above ~100Hz either. Distortion values are much more affected by other factors and can be extremely low with both kind of panels.
The real advantage of flat panels is the easier manufacturing and the possibility to electrically segment the panel. This is done to control dispersion as well as to reduce the capacitive load on the amplifier. Both techniques are not used by RS. The curved panel is mechanically stronger or can be constructed with lower thickness or without additional bracing. This makes them optically rather more pleasing and transparent.
The real disadvantage of most curved panels -besides beeing more complicated and costly in manufacturing- lies in the fact that nearly each of these builds feature mechanically stretched membranes.
A mechanically stretched membrane needs due time to settle to its stable working point. You need a lot of experience to manufacture the panels so that they reach their final working point precisely and constantely after dozends of hours play at the customers home! Flat membranes can be heat treated which allows for final parameter control at the factory. To my knowledge I am the only one who builds heat treated curved panels (and it is different to the procedure and materials as in RS´s book).
So drawing the line a curved panel is in no way inferior to a flat panel, especially not a non-segmented flat panel. It features better practicability and allows for more transparent optics.
Regarding the Youtube-link and bass for an ESL. Listen to 3min 12-3min14 and compare to the claims made before and after
Wether You use a CB or BR or TML doesn´t matter at all when it comes to crossing over from dynamic bass to ESL-panel.
Neither the distribution character nor the SPL-over-distance behaviour of the two channels match! But this is the prime factor of a seamless integration of the two branches. You need the same (or at least a similar) distribution character for one to two octaves around the crossover frequency. The abrupt change in distribution character is audible no matter how good the crossover is done electrically. This fact has lead to the fairy tale of the impossibility of combining heavy paper cones with lightweight film and the misbelief of Fullrangers beeing the superior electrostats.
If the SPL-over-distance behaviour doesn´t match, then will there be just one distance(!) where the SPL of bass and panel is equal. Approaching the speaker the bass will be too loud and on a greater distance the panel plays louder than the bass.
So a typical thin strip ESL (line source) with a single dynamic bass driver (global distribution) can never be the optimal solution of driver integration. The transistion will always remain audible.
The advantage against the proper solution is compactness, lower effort and less cost.
jauu
Calvin
I agree with Calvin's assessment of the merits of flat and curved panels, and I especially agree with his comments on the "heavy woofers can't mate well with light ESL diaphragms" business that Sanders perpetuates in the YouTube clip. I think some reviewer probably said that twenty years ago and it's been getting repeated as fact ever since.
Anyway, back to the main thread topic. I too would be interested in seeing more measurements of diy planar or alternative technology speakers. It's great to hear someone has made something they think sounds wonderful, but posted measurements are probably more useful when it comes to moving us all forward.
Few
Anyway, back to the main thread topic. I too would be interested in seeing more measurements of diy planar or alternative technology speakers. It's great to hear someone has made something they think sounds wonderful, but posted measurements are probably more useful when it comes to moving us all forward.
Few
Calvin said:
The -3 dB/doubling distance of a line source compared to -6 dB/doubling distance of a point source is frequently denoted as a design problem in hybrid designs. But in a regular living room the low bass hasn't a chance for the theoretical -6dB as it meets the walls and ceiling within a short distance.
So it would be very interesting to measure the response at different distances in a real living room. I expect the problem of different radiation patterns being much less than theory predicts or what some people claim if you measure the hybrid in an average livingroom.
I've got a Martin Logan hybrid in my previous living room (30m2) long time ago and this problem didn't show up either, unfortunately no measurements)
Well as to curve vs flat , i would bet on the flat panel , what is critical for a flat panel is the dimn , W- H ratio, very important with a flat panel , less so with a curve panel ..
Agree with mating big woofers to any panel speaker , especially sealed cabinets , a sealed cabinet will never mate with a dipole ...
large woofers cannot be operated above 80hz , smaller woofers are more suited to mate to a panel if you are x-over in the 200-250 range then to a larger woofer for the bass (below 70 ) frequencies ..
Calvin ,
I understand what you are trying to do , by the way you measure efficiency. But since the rest of us use 2.83 V it would give an immediate reference and yes with low impedance the 2.83 v becomes a kind of a cheater as it will represent more than 1 watt , but it would still give us an immediate reference .
2.83 v with Impedance , magnitude and phase could get no clearer...
You said your panels are now commercially available , where would one be able to audition ? how would you rate the sound with say Martin -Logan , who is the largest purveyor of curved Panels ESL 's..
Agree with mating big woofers to any panel speaker , especially sealed cabinets , a sealed cabinet will never mate with a dipole ...
large woofers cannot be operated above 80hz , smaller woofers are more suited to mate to a panel if you are x-over in the 200-250 range then to a larger woofer for the bass (below 70 ) frequencies ..
Calvin ,
I understand what you are trying to do , by the way you measure efficiency. But since the rest of us use 2.83 V it would give an immediate reference and yes with low impedance the 2.83 v becomes a kind of a cheater as it will represent more than 1 watt , but it would still give us an immediate reference .
2.83 v with Impedance , magnitude and phase could get no clearer...
You said your panels are now commercially available , where would one be able to audition ? how would you rate the sound with say Martin -Logan , who is the largest purveyor of curved Panels ESL 's..
Hi ,
In general , I don't think one design is better than another(I.e curved vs flat panels). It all depends on what you want. If you want a high efficiency hybrid , curved is possibly better. But if you want to go lower(like 100Hz) and use a subwoofer , IMO flat wire panel will be much better. It will likely have lower efficiency , but what is the problem of using higher turns ratio step-up ?
a.wayne : why do you think a sealed cabinet cannot mate with dipole ? I think everything depends on specific design . IMO it is easier to build good sealed woofer that a good dipole. Dipole woofer will have to be larger to archieve the same SPL , and high excursions needed to counter sound cancellation will most likely increase THD.
Room standing modes and interactions usually play a big role, and this applies to both cabinet types , and can sometimes have much bigger intact to frequency/impulse responce than different types of speaker cabinets, i think.
In general , I don't think one design is better than another(I.e curved vs flat panels). It all depends on what you want. If you want a high efficiency hybrid , curved is possibly better. But if you want to go lower(like 100Hz) and use a subwoofer , IMO flat wire panel will be much better. It will likely have lower efficiency , but what is the problem of using higher turns ratio step-up ?
a.wayne : why do you think a sealed cabinet cannot mate with dipole ? I think everything depends on specific design . IMO it is easier to build good sealed woofer that a good dipole. Dipole woofer will have to be larger to archieve the same SPL , and high excursions needed to counter sound cancellation will most likely increase THD.
Room standing modes and interactions usually play a big role, and this applies to both cabinet types , and can sometimes have much bigger intact to frequency/impulse responce than different types of speaker cabinets, i think.
Hello Bazukaz,
The best woofer arrangement for hybrid dipole is vented , where the vent is located in the rear. Sealed enclosures have too slow a rise time
and with the mass of it's radiated energy being from the front will have an acoustic center that is so far off the radiating pattern of a dipole, it will never be coherent ..
I'm not a fan of Dipole woofers , I would not consider it based on many reasons, a proper enclosure sounds more like the real thing to me IMO..
Regards,
The best woofer arrangement for hybrid dipole is vented , where the vent is located in the rear. Sealed enclosures have too slow a rise time
and with the mass of it's radiated energy being from the front will have an acoustic center that is so far off the radiating pattern of a dipole, it will never be coherent ..
I'm not a fan of Dipole woofers , I would not consider it based on many reasons, a proper enclosure sounds more like the real thing to me IMO..
Regards,
a.wayne said:
Why sealed systems have too slow rise time ? Sealed systems are less efficient but provide better control of cone movement because sealed air adds additional resistance to cone movement. Further, air springness is more or less linear, unlike driver's suspension.
A vent radiates amost all of its energy at and near tuning frequency. This is typically in 20-50 Hz range. At these frequencies the wavelength is very large, for example , ~10 meters at 30 hz. So there is almost no difference from which point of onclosure it is radiated.However, an advantage of a ported box is that at driver's excursion is lower at tuning frequency , so distortion is lower as well.
Still , I think that a properly designed sealed box with active equalization should outperfom vented , bandpass, and similar boxes in transient response. Is this audible ? I don't know
Regards,
Lukas.
a.wayne: I share Lukas's confusion about why a sealed enclosure should yield a slower rise time for the woofer. The rise time will be determined by the upper frequency limit of the woofer. That is determined by the frequency and slope of the low pass filter used for the woofer, rather than by the nature of the enclosure, unless the woofer is used to such a high frequency that it's limited by its own high frequency extension.
Are you perhaps thinking of the time it takes for the woofer's output to settle back to zero after it's stimulated by a step response, for example? That settling time would be affected by the enclosure type because the enclosure affects the Q and tuning frequency of the woofer-enclosure system.
Of course once you add the low frequency room resonances to the picture the details of the woofer's behavior may get washed out. I'm inclined to think Earl Geddes' approach to the lowest frequencies may be the most sensible---multiple subwoofers arranged in the room to work with the room's resonances and smooth the overall response.
Few
Are you perhaps thinking of the time it takes for the woofer's output to settle back to zero after it's stimulated by a step response, for example? That settling time would be affected by the enclosure type because the enclosure affects the Q and tuning frequency of the woofer-enclosure system.
Of course once you add the low frequency room resonances to the picture the details of the woofer's behavior may get washed out. I'm inclined to think Earl Geddes' approach to the lowest frequencies may be the most sensible---multiple subwoofers arranged in the room to work with the room's resonances and smooth the overall response.
Few
Bazukaz said:
Why sealed systems have too slow rise time ? Sealed systems are less efficient but provide better control of cone movement because sealed air adds additional resistance to cone movement. Further, air springness is more or less linear, unlike driver's suspension.
A vent radiates amost all of its energy at and near tuning frequency. This is typically in 20-50 Hz range. At these frequencies the wavelength is very large, for example , ~10 meters at 30 hz. So there is almost no difference from which point of onclosure it is radiated.However, an advantage of a ported box is that at driver's excursion is lower at tuning frequency , so distortion is lower as well.
Still , I think that a properly designed sealed box with active equalization should outperfom vented , bandpass, and similar boxes in transient response. Is this audible ? I don't know
Regards,
Lukas.
Hello ,
Well Lukas you answered your own question quite well
Vent location is very important ....................
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