Magnetar, your opinion is one thing and you are perfectly free to believe what you wish, including a rather unilateral belief that horns are the perfect solution for every domestic sound application.
However, misstating facts is quite another, and you continue to do that even after having been corrected. I would have to agree with KWY's statement that your knowledge of the physics involved is deplorable, but that hardly prevents you from spreading misinformation at will.
That is true for point source speakers, not dipolar speakers.
I have absolutely no idea what you are trying to say here, but I'm pretty sure it's wrong.
This is 100% verifiably false. Radiation patterns, whether figure-8 (dipolar), cardioid, monopolar, omnipolar, hypercardioid, etc. are defined by the measured response at various degrees from the principle axis. Dipolars subs retain a dipolar radiation pattern at all frequencies, even below the point of significant baffle reinforcement.
Dipolar subs never exhibit an omnipolar radiation pattern. Never. Not for any frequency. What you state is in violation of the laws of physics, yet you continue to state it anyway.
I suppose your misunderstanding isn't that uncommon, as I've seen a self professed genius Ph.D. in physics make the same mistake in logic. But you must remember that although the useable output drops sharply at frequencies below baffle reinforcement, the radiation pattern remains very markedly dipolar (in fact, more so than at higher frequencies).
However, misstating facts is quite another, and you continue to do that even after having been corrected. I would have to agree with KWY's statement that your knowledge of the physics involved is deplorable, but that hardly prevents you from spreading misinformation at will.
That is true for point source speakers, not dipolar speakers.
I have absolutely no idea what you are trying to say here, but I'm pretty sure it's wrong.
This is 100% verifiably false. Radiation patterns, whether figure-8 (dipolar), cardioid, monopolar, omnipolar, hypercardioid, etc. are defined by the measured response at various degrees from the principle axis. Dipolars subs retain a dipolar radiation pattern at all frequencies, even below the point of significant baffle reinforcement.
Dipolar subs never exhibit an omnipolar radiation pattern. Never. Not for any frequency. What you state is in violation of the laws of physics, yet you continue to state it anyway.
I suppose your misunderstanding isn't that uncommon, as I've seen a self professed genius Ph.D. in physics make the same mistake in logic. But you must remember that although the useable output drops sharply at frequencies below baffle reinforcement, the radiation pattern remains very markedly dipolar (in fact, more so than at higher frequencies).
johninCR said:
Because they are easy and sound fine in the mids-- here is the best of the bunch -- Altec 415A Biflex with violin varnish treatment with ESg1 ribbons and a series network - biamped to the basshorns. i also triamped them with a 6th order electronic crossover between the Altec and the ribbons. The problem was the mid couldn't keep up with the rest even though it is 98 db sensitive.
NOTE -- Horn loaded below 100 cycles with side mounted corner loaded 18" drivers in Sensurround horn subs.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
These used diipole "open baffle" mids - the PHL 3451 and the big Heil air motion transformers -- KARLSON loaded bass -- with a 15" PHL 5320.
Magnetar,
Did you try any with swept back "wings". It seems to widen the off axis response on the ones I've used.
I'm a noob with dipoles. Any tips since you've got alot of experience?
How did the Karlson loading work with the setup pictured? I've seen some Karlson type OB subs that looked interesting.
Did you try any with swept back "wings". It seems to widen the off axis response on the ones I've used.
I'm a noob with dipoles. Any tips since you've got alot of experience?
How did the Karlson loading work with the setup pictured? I've seen some Karlson type OB subs that looked interesting.
paulspencer said:
Below is a link to some of my contraptions - after 20 or so I figured it was time to give up on them. Horns bring me much, much closer to complete musical emotional bliss. Why compromise?
Anyone can build an "open baffle." Just take some cardboard cut out a hole and insert your favorite driver.
contraptions
An externally hosted image should be here but it was not working when we last tested it.
johninCR said:
Yes I swept them front and back -- even over and around. As long as the wings are behind the main baffle it has no effect on the off axis response IME.
My tip is to build yourself some horns -- open baffle is OK for mids but in the bass they are backwards.
The Karlson couplers are EXCELLENT in the bass. I haven't built one that will go below 40 Hz but the couplers I built are great 40-200 cycles-- above that you get holes in the response from the front cavity. Highly reccomended! Almost as fun as real horns..
RHosch said:With the utter lack of front wall absorption (concrete block) it is no small wonder that you prefer the radiation pattern of horns to that of dipoles.
What do you have on your walls? Are they concrete? Most of the dipoles I have had in my room I damp the response behind the driver above 300-400 cycles with R-19 and foam. What do you do? If you don't the back wave of 99.9999999% of dynamic drivers sound like crap. Do you like that or do you damp it?
What do you use for bass? Why? What horns have you used in your system? What did you drive them with?
Magnetar,
I still don't get it. Why your experience conflicts so much with other ppls' dipole experience.
That's not enough. Maybe here we have a problem with all your dipoles. There needs to be some account for the bass rolloff due to rear wave cancellation. Either clever combination of driver resonance, baffle size and room gain, or active EQ.
Did you ever use any EQ on your dipoles?
Or did you just stick them on a baffle and find low bass output? You built so many, I can't figure how you could NOT have taken account of this. So why is your experience so different?
BTW - damping of the rear wave is the lesser solution. The better solution is to diffues it. It contributes to airiness, but only if the distance to the rear wall is big enough for a decent delay (perception as reflection which doesn't merge with the original sound) , and ideally, some diffusion.
I still don't get it. Why your experience conflicts so much with other ppls' dipole experience.
That's not enough. Maybe here we have a problem with all your dipoles. There needs to be some account for the bass rolloff due to rear wave cancellation. Either clever combination of driver resonance, baffle size and room gain, or active EQ.
Did you ever use any EQ on your dipoles?
Or did you just stick them on a baffle and find low bass output? You built so many, I can't figure how you could NOT have taken account of this. So why is your experience so different?
BTW - damping of the rear wave is the lesser solution. The better solution is to diffues it. It contributes to airiness, but only if the distance to the rear wall is big enough for a decent delay (perception as reflection which doesn't merge with the original sound) , and ideally, some diffusion.
I still don't get it. Why your experience conflicts so much with other ppls' dipole experience.
--- Probably because they have never heard a good horn! Or they are just happy with what they have ---------
Maybe here we have a problem with all your dipoles. There needs to be some account for the bass rolloff due to rear wave cancellation. Either clever combination of driver resonance, baffle size and room gain, or active EQ.
----I have built dipoles since 1976. I have Eq'd them, changed the QTS through series resistance, build many, many different size/configurations (like the 'H" junk, and placed them all over five different rooms. I almost duplicated Linkwitz's speaker when it came out in Speaker Builder years ago except I used JBL 2235 15" woofers for bass - look at the specs they are better drivers.
Did you ever use any EQ on your dipoles?
----See above ------ YOU HAVE to if you want any resemblance of bass - They are BACKWARDS -- you force the driver into it's worst operating conditions. The OPPOSITE of a good horn!
Or did you just stick them on a baffle and find low bass output? You built so many, I can't figure how you could NOT have taken account of this. So why is your experience so different?
----See my first response. You are repeating yourself!
BTW - damping of the rear wave is the lesser solution. The better solution is to diffues it. It contributes to airiness, but only if the distance to the rear wall is big enough for a decent delay (perception as reflection which doesn't merge with the original sound) , and ideally, some diffusion. [/B][/QUOTE]
----- If you believe this reflected non linear "airiness" is accuracy then I agree. IMO it is fake and the back wave should be damped. Listen to good a recording with two microphones with and without the damping -- it should show you the way.
--- Probably because they have never heard a good horn! Or they are just happy with what they have ---------
Maybe here we have a problem with all your dipoles. There needs to be some account for the bass rolloff due to rear wave cancellation. Either clever combination of driver resonance, baffle size and room gain, or active EQ.
----I have built dipoles since 1976. I have Eq'd them, changed the QTS through series resistance, build many, many different size/configurations (like the 'H" junk, and placed them all over five different rooms. I almost duplicated Linkwitz's speaker when it came out in Speaker Builder years ago except I used JBL 2235 15" woofers for bass - look at the specs they are better drivers.
Did you ever use any EQ on your dipoles?
----See above ------ YOU HAVE to if you want any resemblance of bass - They are BACKWARDS -- you force the driver into it's worst operating conditions. The OPPOSITE of a good horn!
Or did you just stick them on a baffle and find low bass output? You built so many, I can't figure how you could NOT have taken account of this. So why is your experience so different?
----See my first response. You are repeating yourself!
BTW - damping of the rear wave is the lesser solution. The better solution is to diffues it. It contributes to airiness, but only if the distance to the rear wall is big enough for a decent delay (perception as reflection which doesn't merge with the original sound) , and ideally, some diffusion. [/B][/QUOTE]
----- If you believe this reflected non linear "airiness" is accuracy then I agree. IMO it is fake and the back wave should be damped. Listen to good a recording with two microphones with and without the damping -- it should show you the way.
Well, I rest my case. You've tried all options, and you don't like them. Fair enough.
As for myself, I like what I hear from dipoles, bass and mids. I have never heard a good bass horn, true. I wouldn't have space for one, nor do I know anybody who does. I keep an open mind though, I would give a bass horn a try if I built a new house on a large property, just for the fun of it...
As for myself, I like what I hear from dipoles, bass and mids. I have never heard a good bass horn, true. I wouldn't have space for one, nor do I know anybody who does. I keep an open mind though, I would give a bass horn a try if I built a new house on a large property, just for the fun of it...
>The increased cost of the extra drivers can easily be offset by the fact that cheaper drivers can be used with great results and any incremental cost is easily offset by the cost of wood and construction time it takes to build a proper horn.
====
Hmm, it depends on the BW and what is considered good, or at least acceptable, performance. A compression loaded basshorn will be highly damped with a ~flat acoustic phase response in the passband. No point source driver can achieve the latter, and will require very low Q/Le drivers to match the former, which are hardly cheap. Then there's the open chassis design required for dipoles, no cheap stamped steel baskets allowed. Factor in that the mounting area required to match the basshorn's mouth area will be considerably larger if not folded, ergo a ~competitive dipole array will cost considerably more than the basshorn.
====
>I agree with the start of the thread, horns and dipoles are the best and they are very different. In terms of room interaction and accuracy I'd have to give the edge to dipole.
====
Room interaction, yes, horns go omni below ~10^-6/(mouth width or height*wall angle), which will normally be through most of a basshorn's BW. Indeed, the only way to get directivity down low with any closed box design in a typical room is to corner load it. Now all the LF below beaming is theoretically confined to a 90deg wide by 180 deg angle, though in reality, the lower you go, the more acoustic energy extends through the walls if not sufficiently rigid/damped, increasingly bleeding off the acoustic gain.
Accuracy, no, at least not if by accuracy you mean ~faithfully reproducing the signal. That said, down in the <80Hz BW our hearing acuity is so poor that we have a hard time telling when a sub is 180deg out of phase beyond a slight change in loudness, so as long as whatever sub design used can generate the requisite SPL without 'ringing' or other audible ques that locates them, such as high excursion 'pumping' or thermal power compression, then whatever size/design type that works for the app. is sufficient.
====
>I think a dipole line array combined with a multi-driver high output dipole sub (huge baffles are not required) would give you the kind of dynamic presence you prefer.
====
Well, I spent most of a day with the XR290 arrays http://www.roger-russell.com/xr290.htm in an optimized room and was mightily impressed, until I got home and turned on my system that is. As they say, the veil was lifted between me and the music. The fact that they weren't dipole wouldn't have made enough difference to matter IMO, and would have fared worse the lower the signal went.
Mine was physically larger, heavier, and probably would have cost as much or more if finished similarly and sold at retail, but the overall performance difference was clear. Performance wise, it couldn't compete with Magnetar's at the BW extremes, so I would be very surprised if he'd be satisfied with them either.
WRT dipole subs, I helped install/dial in a flown array consisting of eight each 515B very low Q/Le woofers and 511 HF compression horns XO'd at 500Hz for PA address. All were just bolted to some angle iron to make it as compact/strong as practical and to limit their LF response. This was easily the most articulate address sytem I've ever heard, cutting right through the fairly high ambient noise, though theoretically a Unity concept or early WE theater horn would best it. Still, in the ~80-10kHz BW, a large HE dipole 'FR' (several drivers combined to form an apparent point source) would be hard to top in most HIFI apps IMO, with the bottom filled in by whatever best suits the room/SPL required.
Like most things audio though, it all boils down to what sounds 'right' to us since we all seem to hear a little bit differently than the next person, so regardless of what's technically superior, until you've auditioned each kind of system in your room there's no way to know what's best for your app., and why these types of threads are mostly a waste of time/BW IMO.
====
>That is actually pretty funny -- bass wavelengths that wrap around the baffle become omni-directional. This is a simple fact.
====
Not so, they have a figure of eight pattern, hence the lack of strong side boundary interaction due to its nulls. If driven higher up where there's room for standing waves to develop, the rear radiation bounces around and comb filters with the front radiation, and why I don't like dipoles whose rear radiation isn't either damped somewhat or diffused enough to dissipate much of its energy.
As always though, YMMV.
GM
====
Hmm, it depends on the BW and what is considered good, or at least acceptable, performance. A compression loaded basshorn will be highly damped with a ~flat acoustic phase response in the passband. No point source driver can achieve the latter, and will require very low Q/Le drivers to match the former, which are hardly cheap. Then there's the open chassis design required for dipoles, no cheap stamped steel baskets allowed. Factor in that the mounting area required to match the basshorn's mouth area will be considerably larger if not folded, ergo a ~competitive dipole array will cost considerably more than the basshorn.
====
>I agree with the start of the thread, horns and dipoles are the best and they are very different. In terms of room interaction and accuracy I'd have to give the edge to dipole.
====
Room interaction, yes, horns go omni below ~10^-6/(mouth width or height*wall angle), which will normally be through most of a basshorn's BW. Indeed, the only way to get directivity down low with any closed box design in a typical room is to corner load it. Now all the LF below beaming is theoretically confined to a 90deg wide by 180 deg angle, though in reality, the lower you go, the more acoustic energy extends through the walls if not sufficiently rigid/damped, increasingly bleeding off the acoustic gain.
Accuracy, no, at least not if by accuracy you mean ~faithfully reproducing the signal. That said, down in the <80Hz BW our hearing acuity is so poor that we have a hard time telling when a sub is 180deg out of phase beyond a slight change in loudness, so as long as whatever sub design used can generate the requisite SPL without 'ringing' or other audible ques that locates them, such as high excursion 'pumping' or thermal power compression, then whatever size/design type that works for the app. is sufficient.
====
>I think a dipole line array combined with a multi-driver high output dipole sub (huge baffles are not required) would give you the kind of dynamic presence you prefer.
====
Well, I spent most of a day with the XR290 arrays http://www.roger-russell.com/xr290.htm in an optimized room and was mightily impressed, until I got home and turned on my system that is. As they say, the veil was lifted between me and the music. The fact that they weren't dipole wouldn't have made enough difference to matter IMO, and would have fared worse the lower the signal went.
Mine was physically larger, heavier, and probably would have cost as much or more if finished similarly and sold at retail, but the overall performance difference was clear. Performance wise, it couldn't compete with Magnetar's at the BW extremes, so I would be very surprised if he'd be satisfied with them either.
WRT dipole subs, I helped install/dial in a flown array consisting of eight each 515B very low Q/Le woofers and 511 HF compression horns XO'd at 500Hz for PA address. All were just bolted to some angle iron to make it as compact/strong as practical and to limit their LF response. This was easily the most articulate address sytem I've ever heard, cutting right through the fairly high ambient noise, though theoretically a Unity concept or early WE theater horn would best it. Still, in the ~80-10kHz BW, a large HE dipole 'FR' (several drivers combined to form an apparent point source) would be hard to top in most HIFI apps IMO, with the bottom filled in by whatever best suits the room/SPL required.
Like most things audio though, it all boils down to what sounds 'right' to us since we all seem to hear a little bit differently than the next person, so regardless of what's technically superior, until you've auditioned each kind of system in your room there's no way to know what's best for your app., and why these types of threads are mostly a waste of time/BW IMO.
====
>That is actually pretty funny -- bass wavelengths that wrap around the baffle become omni-directional. This is a simple fact.
====
Not so, they have a figure of eight pattern, hence the lack of strong side boundary interaction due to its nulls. If driven higher up where there's room for standing waves to develop, the rear radiation bounces around and comb filters with the front radiation, and why I don't like dipoles whose rear radiation isn't either damped somewhat or diffused enough to dissipate much of its energy.
As always though, YMMV.
GM
Kuei Yang Wang said:
Maybe you could also argue that "depending upon the specific application and personal taste as to which is preferable" EVEN a PROPERLY DESIGNED bass reflex box with a dome tweeter and cone midbass can be suitable.
The reason I say this is that I had one time had a very nice bass reflex MTM. While I did not like small sweet spot afforded by them the bass in my room (27 ft x 16ft x 9.5ft) was adequate.
BTW what about a sealed box using a very low Qtc (say 0.5). I heard a Manger based system using a 8" Vifa and a single Manger driver powered by NAD silver line electronics that was quite nice.
Konnichiwa,
This is only suitable if the desired reproduction is to be severely distorted in the time domain with a very uneven frequency response in the reverbrant field. Or maybe if the owner likes large size and expensive room treatment or if the listening is in the extreme nearfield, all options usually not given in domestic conditions
After length and careful consideration/research I feel that the OPTIMUM speaker for domestic applications has the following characteristics:
1) Omnidirectional EXTREME LOW FREQUENCIES (from here on Superwoofer) system, delivering output to as low a frequency as possible.
2) Dipole Woofer system covering up to around 250...300Hz.#
3) Monopole pointsource Midgrange/Treble system with ideally constant and well controlled directivity. Such directivity control can at low frequencies be achieved with a system similar to the NAO, we used to use this principle in "Column" type PA Speakers which managed a compact form factor and near constant directivity with a hypercardiod pattern down to nearly 100Hz.
Speakers of commercial sources that come to mind as offering or having offered most of the desired charateristics are the Hartley Concert Master (which i have not heard) and the Gradient Revolution (which I have heard and liked a lot, baring the poor dynamic range and obvious compression).
If I had to design such a system for the current day and age with a reasonable compactness and modertae cost I would likely make the system active, using a Seas 6.5" Coaxial Driver (ideally a custom Job combining the CB17RCY woofer section with a Seas 1" Aluminum Dome or even better a Focal TC120) above 300Hz with a suitable (acoustic) delay line to ensure a strong cardiod pattern down to around 150Hz, driven in "current mode" on dome and cone.
The Woofers would be double 10" Woofers (probably Seas CA25REX), again current mode operation and selecting items with a lowish Qm and electrical "feed forward" correction for the Baffle rolloff and the highish Qt (as in current mode Qm = Qt). An option would be to implement feedback on the woofers using electrect mike capsulas to improve linearity at high levels.
If you use the right equalisation and crossovers for this speaker it can be transient coherent and will offer reasonable SPL's with minimal compression and fairly low distortion.
The "Superwoofer" I would treat as optional and direct people to commercial solutions.
Note that the above would be a domestic compromise speaker, not something I'd consider as "ABSOLUTE", I posted about my "Modest Proposal" elsewhere....
Sayonara
navin said:
This is only suitable if the desired reproduction is to be severely distorted in the time domain with a very uneven frequency response in the reverbrant field. Or maybe if the owner likes large size and expensive room treatment or if the listening is in the extreme nearfield, all options usually not given in domestic conditions
navin said:
After length and careful consideration/research I feel that the OPTIMUM speaker for domestic applications has the following characteristics:
1) Omnidirectional EXTREME LOW FREQUENCIES (from here on Superwoofer) system, delivering output to as low a frequency as possible.
2) Dipole Woofer system covering up to around 250...300Hz.#
3) Monopole pointsource Midgrange/Treble system with ideally constant and well controlled directivity. Such directivity control can at low frequencies be achieved with a system similar to the NAO, we used to use this principle in "Column" type PA Speakers which managed a compact form factor and near constant directivity with a hypercardiod pattern down to nearly 100Hz.
Speakers of commercial sources that come to mind as offering or having offered most of the desired charateristics are the Hartley Concert Master (which i have not heard) and the Gradient Revolution (which I have heard and liked a lot, baring the poor dynamic range and obvious compression).
If I had to design such a system for the current day and age with a reasonable compactness and modertae cost I would likely make the system active, using a Seas 6.5" Coaxial Driver (ideally a custom Job combining the CB17RCY woofer section with a Seas 1" Aluminum Dome or even better a Focal TC120) above 300Hz with a suitable (acoustic) delay line to ensure a strong cardiod pattern down to around 150Hz, driven in "current mode" on dome and cone.
The Woofers would be double 10" Woofers (probably Seas CA25REX), again current mode operation and selecting items with a lowish Qm and electrical "feed forward" correction for the Baffle rolloff and the highish Qt (as in current mode Qm = Qt). An option would be to implement feedback on the woofers using electrect mike capsulas to improve linearity at high levels.
If you use the right equalisation and crossovers for this speaker it can be transient coherent and will offer reasonable SPL's with minimal compression and fairly low distortion.
The "Superwoofer" I would treat as optional and direct people to commercial solutions.
Note that the above would be a domestic compromise speaker, not something I'd consider as "ABSOLUTE", I posted about my "Modest Proposal" elsewhere....
Sayonara
The correct sound
I must agree with Magnetar,
There's just something That is not correct with the soundfield of dipoles.
The imaging is not as real as horns, it's there but it is indeed "fake".
The back wave must be elimilated to get the right sound. This is hard to do
for the low frequencies. Placement further from the back wall thus
increasing direct sound helps alot here if your room alows. However this
sound will always mix with the original. The distance is almost always too
short for it to be heard as an echo which is a good thing, imagine multiple soundstages !
Also, depending on the width of the baffle more or less bass energy is
"shorted" to the other side. But not all of this sound is realy lost.
I think that the soundwaves that are sent to the sides are infact not fully
cancelled out but are only in a null at the sides and as they travel further
they reappear again where and thus creating an extra diffuse soundfield.
Sound waves behave like waves in water, they interfere but dont disappear
when they meet.
I thought it was great too, untill i started playing with larger bafles and
horns
Collin
I must agree with Magnetar,
There's just something That is not correct with the soundfield of dipoles.
The imaging is not as real as horns, it's there but it is indeed "fake".
The back wave must be elimilated to get the right sound. This is hard to do
for the low frequencies. Placement further from the back wall thus
increasing direct sound helps alot here if your room alows. However this
sound will always mix with the original. The distance is almost always too
short for it to be heard as an echo which is a good thing, imagine multiple soundstages !
Also, depending on the width of the baffle more or less bass energy is
"shorted" to the other side. But not all of this sound is realy lost.
I think that the soundwaves that are sent to the sides are infact not fully
cancelled out but are only in a null at the sides and as they travel further
they reappear again where and thus creating an extra diffuse soundfield.
Sound waves behave like waves in water, they interfere but dont disappear
when they meet.
I thought it was great too, untill i started playing with larger bafles and
horns
Collin
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.