Hi,
Overkill started a pistonic versus bending thread but didn´t get the hand clapping he wanted. Now he´s trying his luck over here.
As I pointed out in this thread, his analogy completely omisses with the driving electromagnetic forces (the pinpong-ball is similar to a driver with open coil) and as such is no real world situation. Under this condition a Manger behaves the very same as any dynamic driver, because there is a force that centers the voicecoil relative to the pole plate of the magnet. Manger doesn´t use a dedicated spider for this, but the result is the same.
Since I wondered why I never had the revealing experinence with any of the Manger-incarnations, I looked closely at a lot of measurement protocols and papers and the driver itself.
In short....I still wonder is there a functional difference to other dynamic drivers?
With classical measurements like amplitude-phase-response (on axis and off), CSD, impulse, distortion one can see a fairly well behaved wide-bandwidth driver, but nothing outstanding....some plots beeing rather better other rather worse than average.
The question is..are other measurement parameters more revealing like ETC et al and could those explain the audible behaviour?
If You look at the Manger in a black box approach without knowing about the theory behind.....You could guess that it might be a normal dynamic driver of the 8"-class. It features a highish Fs around 80Hz and a lot of small peaks in the impedance plot, suggesting serious resonances within the membrane. The on-axis response is rather smooth compared to other widebandwidth drivers which is a sign for a high damping, i.e. soft membrane material with low-Qs of the break-up modes. The off-axis amplitude response is similar to a soft membraned 6-8"-driver, which claims to reduce its driven mass with increasing frequency, apart from some serious combing artefacts-which too support the large soft-membrane guess. The narrowing of the distribution character begins where one could expect it for any 8"-driver.
Distortion values are rather high and again similar to standard ´softie´.
Looking at Manger´s own pics of membrane behaviour at different freqs, You can see that even at 10kHz the complete membrane is moving and not just a small ring in close proximity to the voicecoil. The pattern is apart from the damping ´star´ similar to those I´d expect from a soft membraned 8"-driver, so this is adverse to their claims.
To me the manger works very much like a quite well behaved, very soft membraned, wide bandwidth 8"-driver, nothing more nothing less. Up till now I don´t see a proof that it works as claimed in theory!
The main differences to any other driver are the use of the very soft membrane and the omittance of a spider as dedicated centering device. And the softness of the membrane allows for the use of a damper on the outer rim of the membrane instead of a surround. The first leads to a smoother frequency response at elevated freqs because of the reduced Q of the break ups, the second is claimed to reduce the count of energy storage mechanisms. I haven´t seen any ETC-curves of the Manger yet -and as said before- would find it interesting since differences to classical drivers should show up here first and clearest(?).
My favourite wide bandwidth transducers, Electrostats, follow the same appoach. They too reduce the number of energy storage mechanisms and can reach exceptional good results. So the idea behind this has a intriguing charme. Anybody out there who has done ETC and similar measurements with Mangers and compared results to a classical driver?
jauu
Calvin
Overkill started a pistonic versus bending thread but didn´t get the hand clapping he wanted. Now he´s trying his luck over here.
As I pointed out in this thread, his analogy completely omisses with the driving electromagnetic forces (the pinpong-ball is similar to a driver with open coil) and as such is no real world situation. Under this condition a Manger behaves the very same as any dynamic driver, because there is a force that centers the voicecoil relative to the pole plate of the magnet. Manger doesn´t use a dedicated spider for this, but the result is the same.
Since I wondered why I never had the revealing experinence with any of the Manger-incarnations, I looked closely at a lot of measurement protocols and papers and the driver itself.
In short....I still wonder is there a functional difference to other dynamic drivers?
With classical measurements like amplitude-phase-response (on axis and off), CSD, impulse, distortion one can see a fairly well behaved wide-bandwidth driver, but nothing outstanding....some plots beeing rather better other rather worse than average.
The question is..are other measurement parameters more revealing like ETC et al and could those explain the audible behaviour?
If You look at the Manger in a black box approach without knowing about the theory behind.....You could guess that it might be a normal dynamic driver of the 8"-class. It features a highish Fs around 80Hz and a lot of small peaks in the impedance plot, suggesting serious resonances within the membrane. The on-axis response is rather smooth compared to other widebandwidth drivers which is a sign for a high damping, i.e. soft membrane material with low-Qs of the break-up modes. The off-axis amplitude response is similar to a soft membraned 6-8"-driver, which claims to reduce its driven mass with increasing frequency, apart from some serious combing artefacts-which too support the large soft-membrane guess. The narrowing of the distribution character begins where one could expect it for any 8"-driver.
Distortion values are rather high and again similar to standard ´softie´.
Looking at Manger´s own pics of membrane behaviour at different freqs, You can see that even at 10kHz the complete membrane is moving and not just a small ring in close proximity to the voicecoil. The pattern is apart from the damping ´star´ similar to those I´d expect from a soft membraned 8"-driver, so this is adverse to their claims.
To me the manger works very much like a quite well behaved, very soft membraned, wide bandwidth 8"-driver, nothing more nothing less. Up till now I don´t see a proof that it works as claimed in theory!
The main differences to any other driver are the use of the very soft membrane and the omittance of a spider as dedicated centering device. And the softness of the membrane allows for the use of a damper on the outer rim of the membrane instead of a surround. The first leads to a smoother frequency response at elevated freqs because of the reduced Q of the break ups, the second is claimed to reduce the count of energy storage mechanisms. I haven´t seen any ETC-curves of the Manger yet -and as said before- would find it interesting since differences to classical drivers should show up here first and clearest(?).
My favourite wide bandwidth transducers, Electrostats, follow the same appoach. They too reduce the number of energy storage mechanisms and can reach exceptional good results. So the idea behind this has a intriguing charme. Anybody out there who has done ETC and similar measurements with Mangers and compared results to a classical driver?
jauu
Calvin
Can Manger be named bending wave transducer when it has pistonic response and no bending wave contribution to the off-axis response, heh? I only see Heckl calculation that supports traveling wave transducers in quasi infinite plate but no one was ever tried to check the theory again. Prof. Dobrucki (AES) only copied those informations. As I know far field response of a bending wave plate depends on nonlinear behavior in the near field and that's why it's hard to find good explanation how this things work.
When I bought my Mangers some years ago there were several reasons for this:
- almost the same performance as an ESL without the size and the hassle with step-up transformers and high voltage
- the only dynamic driver available with a bandwidth of 100 Hz up to 35 kHz
- One of the very few drivers back then that was avaialble with rare-earth magnet
- One of the very few drivers that is manufactured with a consistency of 0.5 dB
These are enough reasons to distinguish it from many other drivers (I didn't say that this makes it better, but it really isn't just the "ordinary" FR driver).
Regards
Charles
- almost the same performance as an ESL without the size and the hassle with step-up transformers and high voltage
- the only dynamic driver available with a bandwidth of 100 Hz up to 35 kHz
- One of the very few drivers back then that was avaialble with rare-earth magnet
- One of the very few drivers that is manufactured with a consistency of 0.5 dB
These are enough reasons to distinguish it from many other drivers (I didn't say that this makes it better, but it really isn't just the "ordinary" FR driver).
Regards
Charles
hi derek
heres the design im thinking of feel free to pick it apart if its not workable
i already have the drivers so i cant change them
2x scanspeak 25w8565-01 per cab crossed to the mangers at 350hz
ob in the same design as your angel in clear acrylic
baffle 350mm wide by 1100mm high
baffle is 20mm acrylic as are the wings ,top and bottom panels
bottom panel will be 500mm long top will be 300mm long with your vpl curve in between
manger will be mounted at the top 50mm down and offsett to one side instead of centre
id like to mount the 2x ss bass drivers as close to the mangers as possible but central on the baffle (side to side) not top to bottom
i realise this will compromise bass though as its better to have them closer to the floor rather than up higher just under the manger
which do you feel is the lesser evil ?
do i have to put a divider in to seperate the manger from the bass drivers or is it ok to have them sharing the same vpl cab and baffle
the above will be run active with my 2x pass f5 and maybe a groundsound crossover
any help advice you could give on the above would be very much appreciated
regards sheafer
heres the design im thinking of feel free to pick it apart if its not workable
i already have the drivers so i cant change them
2x scanspeak 25w8565-01 per cab crossed to the mangers at 350hz
ob in the same design as your angel in clear acrylic
baffle 350mm wide by 1100mm high
baffle is 20mm acrylic as are the wings ,top and bottom panels
bottom panel will be 500mm long top will be 300mm long with your vpl curve in between
manger will be mounted at the top 50mm down and offsett to one side instead of centre
id like to mount the 2x ss bass drivers as close to the mangers as possible but central on the baffle (side to side) not top to bottom
i realise this will compromise bass though as its better to have them closer to the floor rather than up higher just under the manger
which do you feel is the lesser evil ?
do i have to put a divider in to seperate the manger from the bass drivers or is it ok to have them sharing the same vpl cab and baffle
the above will be run active with my 2x pass f5 and maybe a groundsound crossover
any help advice you could give on the above would be very much appreciated
regards sheafer
hi charles
is there a reason for the divider
i thought becouse all the drivers are open baffle a divider would not be required
ive ordered the clear acrylic yesterday the vpl wings are in 15mm
the top bottom and baffle are in 20mm acrylic
cut to size it come to $600 so i just have to glue the cabs together
i priced the cabs in 25mm first but got quite a shock when the price came to $1800 the 25mm is bloudy pricey!!!
i cant wait to try it out this will be the first ob speakers ive ever built or heard and im not sure what to expect
if alls not well i have some sealed cabs ive just built to fall back on i guess , which were part of my original project until i saw the overkill angels and decided to try something similar
is there a reason for the divider
i thought becouse all the drivers are open baffle a divider would not be required
ive ordered the clear acrylic yesterday the vpl wings are in 15mm
the top bottom and baffle are in 20mm acrylic
cut to size it come to $600 so i just have to glue the cabs together
i priced the cabs in 25mm first but got quite a shock when the price came to $1800 the 25mm is bloudy pricey!!!
i cant wait to try it out this will be the first ob speakers ive ever built or heard and im not sure what to expect
if alls not well i have some sealed cabs ive just built to fall back on i guess , which were part of my original project until i saw the overkill angels and decided to try something similar
Ouch !!!!!
I didn't watch out properly ! I was considering a closed box !
With an open baffle it might probably not be needed - but only experimentation would give you an answer.
I would do a design that could easily be adopted for a divider. As a first step I would drive the woofers only and watch how much excursion the MSW makes (with its leads shorted or connected to an amp without input signal).
Regards
Charles
I didn't watch out properly ! I was considering a closed box !
With an open baffle it might probably not be needed - but only experimentation would give you an answer.
I would do a design that could easily be adopted for a divider. As a first step I would drive the woofers only and watch how much excursion the MSW makes (with its leads shorted or connected to an amp without input signal).
Regards
Charles
Slr 5000,
-> I would play two tracks with a digital voltmeter (set to AC, leads across manger, set to capture the Highest level).
-> I would play two sounds through the scanspeak: (i) 350 Hz and (ii) Highest bass frequency where you get maximum xmax excursion.
-> Then run a frequency sweep from 20Hz -> 1 KHz through the Scanspeak again to see if the Manger is effected by another other frequency.
-> Then repeat with a divider!
I'd be very interested to know your results!
AJ.
-> I would play two tracks with a digital voltmeter (set to AC, leads across manger, set to capture the Highest level).
-> I would play two sounds through the scanspeak: (i) 350 Hz and (ii) Highest bass frequency where you get maximum xmax excursion.
-> Then run a frequency sweep from 20Hz -> 1 KHz through the Scanspeak again to see if the Manger is effected by another other frequency.
-> Then repeat with a divider!
I'd be very interested to know your results!
AJ.
hi mate
once the cabs are all setup ill do some tests and post my results
the acrylic does seem pricey for the thicker sheets but its ok as long as you stick below 25mm
as for cutting im told that normal wood routing bits are ok and wood saw blades will work with a slight modification to the teeth
once the cabs are all setup ill do some tests and post my results
the acrylic does seem pricey for the thicker sheets but its ok as long as you stick below 25mm
as for cutting im told that normal wood routing bits are ok and wood saw blades will work with a slight modification to the teeth
Hi AJ
Nice idea to measure the Manger's output when driven by sound pressure.
But be aware that in a real-life situation the Manger would feed its EMF into a short circuit - or well - almost ... (the amp's output impedance). So it woulkd be important to measure A current and not AC volts.
And since we are interested in how the Manger is affected mechanically - the most important thing is still watching its excursion.
Regards
Charles
Nice idea to measure the Manger's output when driven by sound pressure.
But be aware that in a real-life situation the Manger would feed its EMF into a short circuit - or well - almost ... (the amp's output impedance). So it woulkd be important to measure A current and not AC volts.
And since we are interested in how the Manger is affected mechanically - the most important thing is still watching its excursion.
Regards
Charles
Acrylic Angel cabinets.
Hi Sheafer and AJ,
Sorry about the delay in replying (my house move is going badly!) but by the end of the month I should be back online more often.
Re the Angel cabinets:
,
(1) twin Scan Speak Hi Sheafer and AJ,10 inch drivers per side running up to 350Hz should be very nice indeed.
(2) I may be too late with this comment but it’s important to separate and isolate the Manger from the bass cabinet because the bass drivers will transmit a lot of mechanical energy into the Manger if all drivers are bolted to the same baffle.
This will be even more important in an open baffle as the Manger really digs deep with amazing low level detail and sublime imaging that I never heard with any sealed cabinets. Heavy bass mechanical vibrations will mask this musically essential information.
(3) I used a 25mm thick Sorbothane pad custom molded to lock on to the underside of the teardrop shaped eggs ("Prey") which I used to house the Mangers.
I would recommend 700mm to 800mm tall bass / mid cabinets with a separate (sitting on a 10mm to 20mm thick Sorbothane pad)trapezoid open baffle VPL Manger cabinet. The Manger cabinet only need to be 400mm to 500mm tall with the Manger located off centre and approx two thirds of the way up the baffle.
10mm and 12 mm acrylic is fine for the Manger cabinet.
(4) Mounting the bass drivers high up will be fine, the trade off is more low end Vs better driver integration. It’s really personal taste and aesthetics at the end of the day.
(5) Try to avoid adding too much bass boost below 80Hz as this will gobble up the Xmax of the bass drivers. I set the bass / low midrange Vs Manger levels on the DEQX crossover with the bass/low mid about 8dB too high. This then enabled me to EQ the balance correctly with subtractive (troughs) of EQ rather than additive (peaks).
The twin Seas Excel drivers responded really well to this.
For any UK based guy's I still have two pairs of original Angel cabinets in the garage (one pair still has the Seas Excel drivers installed), I am open to reasonable offers....!
Please remember the VPL design needs some EQ' ing as I always use the DEQX crossover (or a PC with Smart Live or similar) and you need to spend some time measuring and setting it all up. Once its set up correctly it’s unbelievable, people can’t believe that all that bass and Manger magic come out of no box.....!
All the best and good luck.
Derek.
Hi Sheafer and AJ,
Sorry about the delay in replying (my house move is going badly!) but by the end of the month I should be back online more often.
Re the Angel cabinets:
,
(1) twin Scan Speak Hi Sheafer and AJ,10 inch drivers per side running up to 350Hz should be very nice indeed.
(2) I may be too late with this comment but it’s important to separate and isolate the Manger from the bass cabinet because the bass drivers will transmit a lot of mechanical energy into the Manger if all drivers are bolted to the same baffle.
This will be even more important in an open baffle as the Manger really digs deep with amazing low level detail and sublime imaging that I never heard with any sealed cabinets. Heavy bass mechanical vibrations will mask this musically essential information.
(3) I used a 25mm thick Sorbothane pad custom molded to lock on to the underside of the teardrop shaped eggs ("Prey") which I used to house the Mangers.
I would recommend 700mm to 800mm tall bass / mid cabinets with a separate (sitting on a 10mm to 20mm thick Sorbothane pad)trapezoid open baffle VPL Manger cabinet. The Manger cabinet only need to be 400mm to 500mm tall with the Manger located off centre and approx two thirds of the way up the baffle.
10mm and 12 mm acrylic is fine for the Manger cabinet.
(4) Mounting the bass drivers high up will be fine, the trade off is more low end Vs better driver integration. It’s really personal taste and aesthetics at the end of the day.
(5) Try to avoid adding too much bass boost below 80Hz as this will gobble up the Xmax of the bass drivers. I set the bass / low midrange Vs Manger levels on the DEQX crossover with the bass/low mid about 8dB too high. This then enabled me to EQ the balance correctly with subtractive (troughs) of EQ rather than additive (peaks).
The twin Seas Excel drivers responded really well to this.
For any UK based guy's I still have two pairs of original Angel cabinets in the garage (one pair still has the Seas Excel drivers installed), I am open to reasonable offers....!
Please remember the VPL design needs some EQ' ing as I always use the DEQX crossover (or a PC with Smart Live or similar) and you need to spend some time measuring and setting it all up. Once its set up correctly it’s unbelievable, people can’t believe that all that bass and Manger magic come out of no box.....!
All the best and good luck.
Derek.
hi mate
my acrylic cabs are already cut and just awaiting glueing so i wont be able to seperate the manger cab but ill get it up and running first and see how it goes
the cabs are 1m high by 350mm wide
the manger is 50mm from the top and offset from centre
the bass drivers are 30mm below the manger and are mounted as close as possible to each other (5mm apart)
the cabs are 300mm deep at the top and 450mm at the base with the vpl curve in between ,i took a guess on the curve so i hope it will be ok
ill use large spikes/feet on the bottom of the cabs so the mangers centre will be 900mm from floor level ,i maybe should have made the cabs taller but i tried to pick the compromise between having the bass drivers as close as possible to the manger whilst still keeping them not too far from the floor for some bass reinforcement
im a little concerned now after your comments above about the manger and bass drivers being on the same baffle but the acrylics cut so ill have too hope for the best and cross my fingers
i will post some pics of the assembled cabs next week
i forgot to add the sharkbites taper in to 160mm at the narowest point
my acrylic cabs are already cut and just awaiting glueing so i wont be able to seperate the manger cab but ill get it up and running first and see how it goes
the cabs are 1m high by 350mm wide
the manger is 50mm from the top and offset from centre
the bass drivers are 30mm below the manger and are mounted as close as possible to each other (5mm apart)
the cabs are 300mm deep at the top and 450mm at the base with the vpl curve in between ,i took a guess on the curve so i hope it will be ok
ill use large spikes/feet on the bottom of the cabs so the mangers centre will be 900mm from floor level ,i maybe should have made the cabs taller but i tried to pick the compromise between having the bass drivers as close as possible to the manger whilst still keeping them not too far from the floor for some bass reinforcement
im a little concerned now after your comments above about the manger and bass drivers being on the same baffle but the acrylics cut so ill have too hope for the best and cross my fingers
i will post some pics of the assembled cabs next week
i forgot to add the sharkbites taper in to 160mm at the narowest point
hi all
as promised heres some pics
ive only ran them with the manger full range so far as i still have not got a crossover so i have not heard the bass drivers as yet
they are in a frosted finish instead of clear
the finish looks uneven in the pics but its just the light and my grotty finger marks all over them
as promised heres some pics
ive only ran them with the manger full range so far as i still have not got a crossover so i have not heard the bass drivers as yet
they are in a frosted finish instead of clear
the finish looks uneven in the pics but its just the light and my grotty finger marks all over them
