hi - navin
ill reply to your post a bit later !
i think ampman and yourself would like a bit more in depth discussion on power handling
in the sence that , efficiency to wattage , how much minimum power required to drive
distortion and compression -
the main factors to decide wattage , before a burn out indian drivers distort like hell , therefore that is not useful wattage
accoustical out - put linearity to power fed by the amplifier ets
ill reply to this and your qs in detail
suranjan
ill reply to your post a bit later !
i think ampman and yourself would like a bit more in depth discussion on power handling
in the sence that , efficiency to wattage , how much minimum power required to drive
distortion and compression -
the main factors to decide wattage , before a burn out indian drivers distort like hell , therefore that is not useful wattage
accoustical out - put linearity to power fed by the amplifier ets
ill reply to this and your qs in detail
suranjan
assesing driver power rating procedures
reply to amp man
HOW THE POWER OUTPUT IS RATED FOR A DRIVER
AND THE CRITERIAS THAT NEEDS TO BE CHECKED BY USERS TO DETERMINE THE RATING
PLUS
WHAT ALL PARAMETERS DOES A RATING DEPEND ON
hi
this statement can be said as correct that :
a power rating given to a driver , means that at all input levels of the driver rating within its specified limit , the driver :
1 ) should perform within the rating in long term use , robustness
2) should perform within very acceptable limits of distortion
3) and should show a certain limit of linearity in relation with the , actual accoustic power output increase to the input power supplied from the amps
without compression
the distortion is now adays mostly the deciding factor of the power rating including long term use
Here it needs to be devided in two sections
FIRST SECTION
in a broad context
distortion / you will find some speakers distorting _ much before the voice coil actually burns out
for eg - considering a driver in which this takes place :
a driver or if they are pro audio or drivers with simple pole vent cooling with the coils set in a tight magnetic gap - the coil can be on a paper former , oridinary wires used in the vc s
the vc s temperature will not rise easily normally 60 deg max , at this time it will distort
then this distortion is not from the vc temperature
(though in most books vc temp is one of the main source of distortion , why ? read on ....)
there are 3 basic types of non linearity in a transducer , these generate distortion , due to this distortion the voice coil heats up / at this moment no amount of cooling can help ,
the distortion effect from driver non linearities are such that it may lead to vc temp rise exponentially leading to vc burn out
the non linearities are
1. non linearity in the suspension mechanism
2. non linearity in the motor sturucture
3. non linearity caused when a coil moves in a permanent magnet motor structure (this is bound to happen even if the above 2 non linearities are addressed well )
to check for these non linearities while purchasing drivers
1. suspension non linearity
for the x - max of the driver you would like to purchase (or the one specified by the manufacturer) meaning you either know the x-max or have one in mind , then :
step a
push the driver cone downwards by that amount , it should go down linearly (the stiffness of the suspension increasing linearly) to the amount of the x-max
step b
pull the cone upwards towards you from beneath and it should come up to the specified x-max , again stiffness increasing linearly
if this does not take place the driver will distort -
unless the transducer manufacturer identifies specifically that such a non - linearity has been addressed , by making suitable compensations in the vc itself
2. motorstructure non linearity
fringe fields exists at the magnetic gap - the motor structure should be - sfg a symmetrical field geometry _ topology
therefore while purchasing a driver look if the motorstructure is - sfg or not
since expenses goes up in a sfg structure it will be specifically mentioned mentioned by the driver manufacturer , to inform customers
3. Non linearity caused when a coil moves in a permanent magnet motor structure
explaining this nature of non linearity is complex , anyone interested can see the sections on shorting rings in my thread
what is important
is that : -
has this been addressed by the transducer manufacturer
it is addressed by shorting rings placed in the motorstructure
since this too involves expence , and a considerable slow down in the manufacturing process this too will be specified by the driver manufacturer , to inform customers
-
the above are the main sources of distortion that determines the safe operating power of a driver , and are not the only sources of driver distortion (other sources of distortion are eddys , bottoming to name a few)
due to such complex stuff good driver manufacturers all over the world can be counted on finger tips
------------------------------------------------------------------------------------
SECOND SECTION
in good drivers context
good drivers are in which all the above criterias have been addressed
then the rise in vc temperature over long time use / the cooling efficiency comes in , and mostly all speaker failures of reputated manufacturers result from vc burn out (as mentioned by Navin)
mostly these limits are tested thoroughly and drivers tested to distruction and safe regions specified
i have found driver malfunction due to negligence of owners to go in for a service contract when pro audio drivers are used eg - movie halls , discs
in home audio , sources of reputated driver burn outs are :
a)
amp malfunction and dc component generation in the drive signal or signal clipping
speacially when high power speakers are used by under powered amps , many people do not even consider that a 35 w amp can damage a 100 w speaker system _ plain simple signal clipping can distroy well made drivers
if you have an under powered amp please ask a sound engineer to determine the clipping levels of your amp and restrict from running at clipping levels (in high end audio amps from manufacturers like Nad and onwards this is built in as standard , in the circuitry , therefore the prices)
b)
or the suspension parts have outlived _ may be the owner !
thanks Amp Man , hope this comes of use ,
Suranjan Das Gupta
Transducer design engineer
reply to amp man
HOW THE POWER OUTPUT IS RATED FOR A DRIVER
AND THE CRITERIAS THAT NEEDS TO BE CHECKED BY USERS TO DETERMINE THE RATING
PLUS
WHAT ALL PARAMETERS DOES A RATING DEPEND ON
hi
this statement can be said as correct that :
a power rating given to a driver , means that at all input levels of the driver rating within its specified limit , the driver :
1 ) should perform within the rating in long term use , robustness
2) should perform within very acceptable limits of distortion
3) and should show a certain limit of linearity in relation with the , actual accoustic power output increase to the input power supplied from the amps
without compression
the distortion is now adays mostly the deciding factor of the power rating including long term use
Here it needs to be devided in two sections
FIRST SECTION
in a broad context
distortion / you will find some speakers distorting _ much before the voice coil actually burns out
for eg - considering a driver in which this takes place :
a driver or if they are pro audio or drivers with simple pole vent cooling with the coils set in a tight magnetic gap - the coil can be on a paper former , oridinary wires used in the vc s
the vc s temperature will not rise easily normally 60 deg max , at this time it will distort
then this distortion is not from the vc temperature
(though in most books vc temp is one of the main source of distortion , why ? read on ....)
there are 3 basic types of non linearity in a transducer , these generate distortion , due to this distortion the voice coil heats up / at this moment no amount of cooling can help ,
the distortion effect from driver non linearities are such that it may lead to vc temp rise exponentially leading to vc burn out
the non linearities are
1. non linearity in the suspension mechanism
2. non linearity in the motor sturucture
3. non linearity caused when a coil moves in a permanent magnet motor structure (this is bound to happen even if the above 2 non linearities are addressed well )
to check for these non linearities while purchasing drivers
1. suspension non linearity
for the x - max of the driver you would like to purchase (or the one specified by the manufacturer) meaning you either know the x-max or have one in mind , then :
step a
push the driver cone downwards by that amount , it should go down linearly (the stiffness of the suspension increasing linearly) to the amount of the x-max
step b
pull the cone upwards towards you from beneath and it should come up to the specified x-max , again stiffness increasing linearly
if this does not take place the driver will distort -
unless the transducer manufacturer identifies specifically that such a non - linearity has been addressed , by making suitable compensations in the vc itself
2. motorstructure non linearity
fringe fields exists at the magnetic gap - the motor structure should be - sfg a symmetrical field geometry _ topology
therefore while purchasing a driver look if the motorstructure is - sfg or not
since expenses goes up in a sfg structure it will be specifically mentioned mentioned by the driver manufacturer , to inform customers
3. Non linearity caused when a coil moves in a permanent magnet motor structure
explaining this nature of non linearity is complex , anyone interested can see the sections on shorting rings in my thread
what is important
is that : -
has this been addressed by the transducer manufacturer
it is addressed by shorting rings placed in the motorstructure
since this too involves expence , and a considerable slow down in the manufacturing process this too will be specified by the driver manufacturer , to inform customers
-
the above are the main sources of distortion that determines the safe operating power of a driver , and are not the only sources of driver distortion (other sources of distortion are eddys , bottoming to name a few)
due to such complex stuff good driver manufacturers all over the world can be counted on finger tips
------------------------------------------------------------------------------------
SECOND SECTION
in good drivers context
good drivers are in which all the above criterias have been addressed
then the rise in vc temperature over long time use / the cooling efficiency comes in , and mostly all speaker failures of reputated manufacturers result from vc burn out (as mentioned by Navin)
mostly these limits are tested thoroughly and drivers tested to distruction and safe regions specified
i have found driver malfunction due to negligence of owners to go in for a service contract when pro audio drivers are used eg - movie halls , discs
in home audio , sources of reputated driver burn outs are :
a)
amp malfunction and dc component generation in the drive signal or signal clipping
speacially when high power speakers are used by under powered amps , many people do not even consider that a 35 w amp can damage a 100 w speaker system _ plain simple signal clipping can distroy well made drivers
if you have an under powered amp please ask a sound engineer to determine the clipping levels of your amp and restrict from running at clipping levels (in high end audio amps from manufacturers like Nad and onwards this is built in as standard , in the circuitry , therefore the prices)
b)
or the suspension parts have outlived _ may be the owner !
thanks Amp Man , hope this comes of use ,
Suranjan Das Gupta
Transducer design engineer
1. suspension non linearity
2. motorstructure non linearity
3. Non linearity caused when a coil moves in a permanent magnet motor structure
hunter,
pls take this with a large grain of salt. i dont mean to be condesending, insulting in anyway in my comments below. I am very sensitive to anyone in India who is getting into the audio business. Like I have mentioned before (via Chat) I feel there are easier (honest) ways to make money. Audio is a very tough business esp when one end of the market is sewn up by Sony and Bose and the other end has a few mid sized gorillas like Theil, Wilson, Sonus Faber etc.. and as far as speaker go cos like B&W offers everything in the middle.
I have never seen any business where the % of faliures is so high as "high - end" audio. Even those cos that do not fail struggle and limp along for a long time. I appreciate all the effort you are making.
today most good drivers take care of suspension linearity and motor structure and linearity when the motor structure moves in magnetic gap. technologies and techniques like copper shorting rings, ferro fluid, dual spiders and magnets, resonance cavites, sophisticated rubber surrounds like Norosex have been around a while. There is enough technology out there for the larger drivers cos. to use to make a good driver - that is probably why many of the chinese/malay drivers I see recently are quite good.
A few brands even have even reduced their tolerance levels to such a degree that pair matching is not very nesscary.
Driver design is a matter of compromises esp convential driver design. If you want a big linear Xmax you will usually get a reduction in sensitivity, if you try and up the sensitivity Fs goes up. You cant compare the vocals of a 4" midrange to a 4" midbass.
for example: take Scan Speak 15W/4531 v/s the 15M/4531 OR Focal's 7K4412 v/s their 7K6411.
As a driver manufactuer you will get a lot of strange requests. everyone you meet, esp DIYers like me, will ask for this or that most of which does not fit into your regular range. What I would advise is that you stick to the OEM stuff. That will drive your business volumes and then offer a few special drivers (souped up stuff you make for the OEM market) to the DIY market.
Marketing is a very expensive proposition. Viral marketing takes time to get a foot hold esp. in audio which has seen it's share of "newer and better" technologies and theories.
Once you have a viable business (enough to be doing this full time) then you can look at making a few drivers that will NOT be available to anyone but will be used in a speaker system that you will make with your brand.
Cabasse, Focal (JM lab), etc.. follow this concept.
Like a few enterpreneus have proven already (Mr Rath and Mr Mukherjeee esp.) India can be very cost effective in markets where the volumes dont justiy moving to China.
2. motorstructure non linearity
3. Non linearity caused when a coil moves in a permanent magnet motor structure
hunter,
pls take this with a large grain of salt. i dont mean to be condesending, insulting in anyway in my comments below. I am very sensitive to anyone in India who is getting into the audio business. Like I have mentioned before (via Chat) I feel there are easier (honest) ways to make money. Audio is a very tough business esp when one end of the market is sewn up by Sony and Bose and the other end has a few mid sized gorillas like Theil, Wilson, Sonus Faber etc.. and as far as speaker go cos like B&W offers everything in the middle.
I have never seen any business where the % of faliures is so high as "high - end" audio. Even those cos that do not fail struggle and limp along for a long time. I appreciate all the effort you are making.
today most good drivers take care of suspension linearity and motor structure and linearity when the motor structure moves in magnetic gap. technologies and techniques like copper shorting rings, ferro fluid, dual spiders and magnets, resonance cavites, sophisticated rubber surrounds like Norosex have been around a while. There is enough technology out there for the larger drivers cos. to use to make a good driver - that is probably why many of the chinese/malay drivers I see recently are quite good.
A few brands even have even reduced their tolerance levels to such a degree that pair matching is not very nesscary.
Driver design is a matter of compromises esp convential driver design. If you want a big linear Xmax you will usually get a reduction in sensitivity, if you try and up the sensitivity Fs goes up. You cant compare the vocals of a 4" midrange to a 4" midbass.
for example: take Scan Speak 15W/4531 v/s the 15M/4531 OR Focal's 7K4412 v/s their 7K6411.
As a driver manufactuer you will get a lot of strange requests. everyone you meet, esp DIYers like me, will ask for this or that most of which does not fit into your regular range. What I would advise is that you stick to the OEM stuff. That will drive your business volumes and then offer a few special drivers (souped up stuff you make for the OEM market) to the DIY market.
Marketing is a very expensive proposition. Viral marketing takes time to get a foot hold esp. in audio which has seen it's share of "newer and better" technologies and theories.
Once you have a viable business (enough to be doing this full time) then you can look at making a few drivers that will NOT be available to anyone but will be used in a speaker system that you will make with your brand.
Cabasse, Focal (JM lab), etc.. follow this concept.
Like a few enterpreneus have proven already (Mr Rath and Mr Mukherjeee esp.) India can be very cost effective in markets where the volumes dont justiy moving to China.
.
I totally agree with Navin on the above comments, people will be asking strange things, which might be funny to you sometimes reasons are that they are not always expert's on driver technology, than you may start corresponding, explaining, educating, quoting & finally bargaining on price for two numbers in most cases. Do you have such time for every customer? I understand for OEM at design-stage.
I totally agree with Navin on the above comments, people will be asking strange things, which might be funny to you sometimes reasons are that they are not always expert's on driver technology, than you may start corresponding, explaining, educating, quoting & finally bargaining on price for two numbers in most cases. Do you have such time for every customer? I understand for OEM at design-stage.
Suranjan's contact
Hi Kanwar!
It's been a while since you wrote to me - I was out of country for a while, AND been busy with a brand new baby... will you by any chance still be able to provide me with the Suranjan/his partner's address/phone? I am very interested in getting latest prices and specs of his drivers.
Do you know if anyone has built anything from his drivers? I think Navin was going to, but haven't seen anything after that...
Regards,
Neel
Hi Kanwar!
It's been a while since you wrote to me - I was out of country for a while, AND been busy with a brand new baby... will you by any chance still be able to provide me with the Suranjan/his partner's address/phone? I am very interested in getting latest prices and specs of his drivers.
Do you know if anyone has built anything from his drivers? I think Navin was going to, but haven't seen anything after that...
Regards,
Neel
i had asked suranjan to make me a pair fo 8" woofers and had arranged for a friend of mine in calcutta to pay him and carry the woofers to mumbai but the woofers did not materilse.
i am still awaiting these woofers. the cabinets (30 liters sealed) boxes are ready. since surnjan does this part time and knowiing the diffculties of this business i am prepared to wait as long as it takes.
i sincerly wish hunter audio all the success as any success by an indian manufactuer should be aplauded. the audio business is not easy more so in india caught as we are between the low cost chinese imports and the european and american audiophile products.
i am still awaiting these woofers. the cabinets (30 liters sealed) boxes are ready. since surnjan does this part time and knowiing the diffculties of this business i am prepared to wait as long as it takes.
i sincerly wish hunter audio all the success as any success by an indian manufactuer should be aplauded. the audio business is not easy more so in india caught as we are between the low cost chinese imports and the european and american audiophile products.
no i did not as i do not know his partner. i would be the first to adive hunter audio to not entertain orders under 100 woofers and only when they are well on the way to being profitable should they enterain DIY.
DIY is the most demanding segment of any business (be it audio or hovercrafts). the volumes are small and the margins are thin. if and when hunter is able to build a business that has reached critical mass they could then make "modified" versions of their existing range of drivers for the DIY market.
Hunter would be best served by making a 12" and 6" woofer and a 1" tweeter. the 12" sub market is the biggest and the 6" 2way is a mainstay for any speaker company using dynamic drivers (other than fullrange).
Next in line would be a 3-4" full range that can be used in a small box (a la TB's 871 and 654 and fostex's 103 and 107). this would be primarily targeted at the HT market.
Then I would add a 8" woofer and a leaf/ribbon tweeter and later a 10" and 15" Pro woofers (a la focal audioum).
modified versions of the 6" could be targeted at the vifa PL series or Focal or SS midbass and the 1" tweeter could be modified to compete with the better domes.
modified versions of the 8" would have specs to serve the DIYer who is building a TL (few TLs are made in the commercial market). and so on....
DIY is the most demanding segment of any business (be it audio or hovercrafts). the volumes are small and the margins are thin. if and when hunter is able to build a business that has reached critical mass they could then make "modified" versions of their existing range of drivers for the DIY market.
Hunter would be best served by making a 12" and 6" woofer and a 1" tweeter. the 12" sub market is the biggest and the 6" 2way is a mainstay for any speaker company using dynamic drivers (other than fullrange).
Next in line would be a 3-4" full range that can be used in a small box (a la TB's 871 and 654 and fostex's 103 and 107). this would be primarily targeted at the HT market.
Then I would add a 8" woofer and a leaf/ribbon tweeter and later a 10" and 15" Pro woofers (a la focal audioum).
modified versions of the 6" could be targeted at the vifa PL series or Focal or SS midbass and the 1" tweeter could be modified to compete with the better domes.
modified versions of the 8" would have specs to serve the DIYer who is building a TL (few TLs are made in the commercial market). and so on....
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