My driver building Experiment

[somakmaitra]

Hello Everybody ,
This is my first post in this wonderful forum .
This is my attempt at building a couple of 8 inch woofer using locally available parts .
The rationale of such a project :-
Indian made drivers are absolutely crap in every sense (Excluding a few )I dissected a number of boltons the results are horrible
Picasa Web Albums - somak - speaker modif...
2.No pair of finished products are the same (There are exceptions).
3.We have very good skilled lathe operators in Kolkata.
4.Now we have access to acceptable quality of cones and coils .
5. The quality of magnets are not that great ,but cant help :sad:
6.Most 8 inch woofer have 1 inch voice coils .

I was inspired by sumit's efforts which is documented in diyaudio.com
Pictures by sumitdutta77 - Photobucket

I have built the 8 inch woofer and I am happy with the outcome .Havent had the time to mount it or measure it . But will do it soon .

Costs Breakup :-
1. paper Cone with rubber surround Rs 20 each
2. Kapton Voice coil Flat wire Diagonally slit Rs 40.00 each
3. Basket Powder coated aluminum Rs 120 each
4. Magnet and the plate assembly Rs 200 each
5 .Spider Rs 5.00
6. Copper pipe for Faraday ring Rs 400
7 Machining cost for finishing the plates
and inserting the faraday rings Rs 300

8. Adhesive two part & lead wire (I already had )

Picasa Web Albums - somak - speaker

This is a DIY effort .
Thanks to Sumit for the inspiration
One small foot note :-
DIY Driver building is doable and quite enjoyable :yahoo:

 

[gobble]

Great effort - but how is the SQ? :licklips:

Cheers

 

[suri]

yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeaaaaaaaagh!!!!!!!!:clapping::clapping:


please immediately contact soundsgreat on this forum. if you and he get together you (we) will end up with world-class drivers

and hey listen, if you persevere, you could make more money than, say, the mushroom king of panjab!

i wish you all the best, but please contact soundsgreat

 

[suri]

Now, who is Sumit? introductions? oops?

 

[somakmaitra]

Thanks for such inspiring words

Sumit's Speaker building thread:-

diyAudio Forums - searched enough for drivers ....INDIA - Page 1

The sound quality of the woofer is quite smooth and controlled .

Regards ,
Somak

 

[goldyrathore]

Very good work somakmaitra. How do they measure? Did you measure the T/S specs. IMHO the magnets available locally are not strong enough and so result in high Qe and therefore high Qts as well. I have not checked the scene lately and am only reflecting from my experience with reconing some drivers (which I did just for the fun).

Congratulations for getting good sonic results.

 

[somakmaitra]

hello goldy,
the magnets are really bad but cant help as they are all that are available (Low qualityChinese stuff) all indian magnet manufacturers have gone out of business . Sumit suggested a way around of demagnetising and then remagnetising will try that . Of late havent had the time to check the t/s parameters due to work load and family commitments .
I have jus got my panasonic mic from digikey will measure in due time .

But I was satisfied by the fact that they are far better than the shit drivers that are available in kolkata .

importing the speakers are very expensive .If we get good magnet the result will be far better .

Regards ,
Somak

 

[ravs]

hi all,

making a transducer with with locally available parts is not a bigdeal.join all the parts together and charge the magnet. driver wil definately produce the sound.
but with useless parameter.to make a proper driver ie for desired t/s parameter
you should know the spider flexiblity.cone compliance. magnet type.voice coil length and gauge of the wire according to pole piece and wattage.you cant get y30-35 cateory magnets.top/bottom plates and pole piece are made of dirty or
impure iron.i have searched the whole lajpat rai market for all these but i found nothing as far as sumit is concerned he has imported cone and spiders.which cost around 20-25$ per cone.which is not possible for normal indian diyer.if any body have any source for reliable source pleaese do let me know.


ravs




be a vegeterian.......

 

[kaushik]

Ravs , one thing i like to add is building a high end speaker in a short span of time is not practical assumption ..
but remember the net is a source of unending info ..
constantly if you try at some point you will have a good working formula:licklips:..

break the goal into parameters
1)info of materials and parameters: ways to go
a)forums b)email exchange with experts
2)usable materials: info from sumit,somakmaitra..
3)what parameters ,spider flexibility ,cone complience:
loudspeaker motor simulators are there but costly..and simulation is the extreme stage of improvements..
for now try building some variants ,info from sumit ...i know the cone can be treated with some materials
for improvements ,
here is a link for some good docs :audioXpress - Voice Coil Articles and Addenda

A Look at Speaker Cones pdf is one important document.

4)a plug-in type basket arrangement for repeated tests .. for fine tuning TS parameters

 

[somakmaitra]

Hello ,
I totally agree with Ravs

making a transducer with with locally available parts is not a bigdeal.join all the parts together and charge the magnet. driver wil definately produce the sound.

I just did a bit of retro fitment I did an extended pole piece and added a thick copper Faraday ring (followed the lambda drivers).
To get a better BI I chose a heavy magnet but the quality was still horrible .
Actually I was frustrated with the quality of woofers available at Kolkata .
The voice coils were quite good having diagonally slit kapton and flat copper wire imported from china ,cone was from Jupiter who claims to supply to big OEM's like morel etc Jupiter

Regarding the spider you can eliminate the same totally see the Steen Duelund experiment .
for the top plate and bottom plate you can get low carbon steel from the steel dealers .But you require good lathe operator to get the job done .The quality available in lajpat market is horrible Kolkata spares are a bit better .

You can further take reference from the book loudspeaker cook book .

I enjoyed the exercise hope you will also feel the same .The aim was pure fun, DIY and to get something better than what was available locally .
regarding simulation software ,some are available in torrent I will not comment further on them .


regards and happy DIYing ,

Somak

 

[ravs]

Ravs , one thing i like to add is building a high end speaker in a short span of time is not practical assumption ..
but remember the net is a source of unending info ..
constantly if you try at some point you will have a good working formula:licklips:..

break the goal into parameters
1)info of materials and parameters: ways to go
a)forums b)email exchange with experts
2)usable materials: info from sumit,somakmaitra..
3)what parameters ,spider flexibility ,cone complience:
loudspeaker motor simulators are there but costly..and simulation is the extreme stage of improvements..
for now try building some variants ,info from sumit ...i know the cone can be treated with some materials
for improvements ,
here is a link for some good docs :audioXpress - Voice Coil Articles and Addenda

A Look at Speaker Cones pdf is one important document.

4)a plug-in type basket arrangement for repeated tests .. for fine tuning TS parameters

hi kaushik,

i have been tangling around for 7-8 months looking for some measured specs of stuffs.searching ways to things get done.not every guy have the equipment to test the stuff accurately.not every guy have access to cnc lathe machine nor they know to operate it.
it is not possible to import every thing outside the country.steel dealers are not willing to sell few sheets of steel they are wholesalers.yes net is never ending story.one guy is measuring xmax with the help of radar on diyaudio.
so do you expect every one to own a radar just to measure xmax of driver.
7-8 months are not so small figures.forget about motor simulation.just recone a driver you wont even get near the original specs.iam not asking to improve
the cone properties.iam asking the solution to test them for their compliance
or stiffness.i have experimented a lot with different size magnets,voicecoils,
spiders and cones and you know something i could not push the force factor {bl} beyond 7 with 220mm magnets and different simulations for different pole piece diameter.


a plug-in type basket arrangement for repeated tests .. for fine tuning TS parameters

here it comes again .different basket size means different flexiblities of spider.
this is why i was asking for measured specs.just throw them in simulation soft
you are just 2-7% away from simulated specs.

anyway thanks for the links


ravs



be a vegeterian ........

 

[ravs]

Hello ,
I totally agree with Ravs I just did a bit of retro fitment I did an extended pole piece and added a thick copper Faraday ring (followed the lambda drivers).
To get a better BI I chose a heavy magnet but the quality was still horrible .
Actually I was frustrated with the quality of woofers available at Kolkata .
The voice coils were quite good having diagonally slit kapton and flat copper wire imported from china ,cone was from Jupiter who claims to supply to big OEM's like morel etc Jupiter

Regarding the spider you can eliminate the same totally see the Steen Duelund experiment .
for the top plate and bottom plate you can get low carbon steel from the steel dealers .But you require good lathe operator to get the job done .The quality available in lajpat market is horrible Kolkata spares are a bit better .

You can further take reference from the book loudspeaker cook book .

I enjoyed the exercise hope you will also feel the same .The aim was pure fun, DIY and to get something better than what was available locally .
regarding simulation software ,some are available in torrent I will not comment further on them .


regards and happy DIYing ,

Somak

hi somakmaitra,

i have tried different size of magnets and coils.i always get higher qe and lower bl.chinese products are much better then the indian ones.atleast they sell what they say.but now indian shopkeepers are selling their lowest grade
product on the name of china.still finding solutions from wherever possible.


thanks for STEEN DUELUND link.


ravs


be a vegeterian.......

 

[kaushik]

i can tell you some facts ....

good drivers are the key components of audio systems
once you get the right combo you will hit the jack pot
this may even take another year,

what you need to is give this task a break , roaming
markets filled with cheap stuff will lead to frustration..

leave it for some time and after a while fresh Ideas will come up ,
i try this .. and it works!
for an attenuator part i was
busy searching..made one too but was not as smooth,
i gave it a break,after some time i got a highly reliable part.

without online shopping from outside (direct import from china may be needed) you will be roaming around the same parameter , local markets are full of crap .

and hence some money you may have to spend! Good thing is small parcels customs dunt take duty.

regarding xmax if you really want i can help you with an optical sensor.


small steel qty are available specially at the fabricators places dont go to whole sellers,here Bangalore all fabricators nearby my place r very friendly!

 

[somakmaitra]

I agree with you Kaushik ,
My frustration arose out of the sheer frustration of non availability of good quality parts in kolkata .
Import is out of question as i have a very shallow pocket lol: .now there are a lot of good speakers available at parts express on buyout .But when I tried on building the woofer importing a respectable woofer would have sent me back by 10,000/- I have bought a couple of drivers from USA (HIVI ones ) and the quality is very good .
Right now there is a scarcity of good 6 inch woofers in kolkata and to add to the frustration even cast baskets of 6 inches are also not available.
I have the Loudspeaker Design Cookbook which is a great book with tons of info I would request ravs to get one I bought it from Madisound which was on sale .
for measuring Xmax vance has a very good methord which uses a simple method.

My aim was not to make a driver comparable to VIFA etc but an unit better than the boltons etc which I believe is possible even with the stock parts .
I believe the biggest problem with the local suppliers is the lack of consistency which we can care fully avoid .
Good imported voice coils are available now which are imported from china or thailand .
The cones of jupiter are also quite good ,cast basket above 8' are also available .
Only prob are ferrite which cant be helped ,Summit has suggested to go for magnetise ,demagnetise and remagnetising process which I will try out .

Regards ,
Somak

 

[quad]

All power to Somak, Sumit, Srikanth and others who
are doing this innovative and pioneering work.
My best wishes to them to keep plugging at it,
though getting parts, information, test tools etc is
very challenging and expensive.

Hope with Sumit/Somak doing a woofer
and Srikanth building a tweeter, and perhaps Kaushik,
Ravs et al building a midrange, it may be the beginning
of a great, collaborative driver story from India.

 

[kaushik]

I agree with you Kaushik ,
My frustration arose out of the sheer frustration of non availability of good quality parts in kolkata .


My aim was not to make a driver comparable to VIFA etc but an unit better than the boltons etc which I believe is possible even with the stock parts .

The important part is to 'believe',and surely if you try
removing the deadlocks one day things will be possible.

Good imported voice coils are available now which are imported from china or thailand .
The cones of jupiter are also quite good ,cast basket above 8' are also available .

That is encouraging,now things of importing drivers is bit easy,20north has dayton reference drivers at 2.5k ..may serve a reference for many .

For light weight components,try asking sample purchase from some china company (act like you are running a small company),there are many quality suppliers in china and they allow 2-5 pcs as sample order just to evaluate ,also pricing is very good.

For an example I have got quote for 30VA toroidals 5$ each for small qty .

Only prob are ferrite which cant be helped ,Summit has suggested to go for magnetise ,demagnetise and remagnetising process which I will try out .

look at..
Speaker magnets ferrite speaker magnet magnetizer/demagnetizer loudspeaker magnetizer speaker magnets specification
you can order light weight sample and evaluate..
let me get search for a magnetizer schematic.. should be easy to build.
useful links,
small magnetizer with schematic:http://www.antennex.com/hws/ws0300/magdemag.htm
patent:http://www.patentstorm.us/patents/6310532/description.html

quad,
thanks for the lines...others please gather some online info
and contribute here
Interesting site Axiom audio building woofer manually(pics) :
http://www.axiomaudio.com/research_WooferBuilding.html

 

[ravs]

hi guys do you have any idea of what is the gauge of wire used in 15-18 inchi
pro woofer voice coils used by big manufacturer eminence .fane,beyma etc for 600-800 watt.i think its between 27 to 24 awg.


thanks in advance


ravs



be a vegeterian

 

[ravs]

hi cranky,

iam building a 15 or 18 inchi sub.according to simulations done by finemotor
gives me the gauges around 27 to 24 awg.i cant find the power handlng capablityof the coils.4 inch in diameter.


thanks


ravs



be a vegeteran

 

[soundsgreat]

Hi,

I've been following this thread from day one and didn't post for various reasons !

The voice coils were quite good having diagonally slit kapton and flat copper wire imported from china ,cone was from Jupiter who claims to supply to big OEM's like morel etc

Am in a process of building 6.5" midbass to complement my DIY dome tweeter and thought (still thinking ) to open a thread (which I will in due time course) !

Somak can you please give me a link or contact details or help me get a similar quality voice coil ? I need 32,37,50MM dual layer (preferably 32Gauge) with 20MM of winding height !

Anyone who can give me some info on the same will be much appreciated !

Right now there is a scarcity of good 6 inch woofers in kolkata and to add to the frustration even cast baskets of 6 inches are also not available.

Same problem here aswell :lol: ! So I decided and have got the Baskets done in Aluminum !

Also some good cones to go,I have already shortlisted few but need as much as I can for the final design !

Jupiter is no good !!! contacted them several times with no result,they don't have courtesy to even respond to mails !

Anyways some brief points that I have in mind for the design ! Hope Am not trying to deviate this thread !

1.Pole piece ( or T-Yoke) 32,37,50 (will finalise on one of these based on results)

2.Top and bottom plates 7,10MM

3. Air Gap 2-2.5MM

4.Voice coil : Dual Layer with above said spec

5. Cone : Air dried (or if I can find a Sandwich or woven cone much better) with rubber surround.

6. Magnet : 120MM Y30 (as Y35 is literally not available in India)

Thats all I can of for now ! let me know what you guys think and have to say about this !

Regards.

 

[ravs]

Hi,

I've been following this thread from day one and didn't post for various reasons !



Am in a process of building 6.5" midbass to complement my DIY dome tweeter and thought (still thinking ) to open a thread (which I will in due time course) !

Somak can you please give me a link or contact details or help me get a similar quality voice coil ? I need 32,37,50MM dual layer (preferably 32Gauge) with 20MM of winding height !

Anyone who can give me some info on the same will be much appreciated !



Same problem here aswell :lol: ! So I decided and have got the Baskets done in Aluminum !

Also some good cones to go,I have already shortlisted few but need as much as I can for the final design !

Jupiter is no good !!! contacted them several times with no result,they don't have courtesy to even respond to mails !

Anyways some brief points that I have in mind for the design ! Hope Am not trying to deviate this thread !

1.Pole piece ( or T-Yoke) 32,37,50 (will finalise on one of these based on results)

2.Top and bottom plates 7,10MM

3. Air Gap 2-2.5MM

4.Voice coil : Dual Layer with above said spec

5. Cone : Air dried (or if I can find a Sandwich or woven cone much better) with rubber surround.

6. Magnet : 120MM Y30 (as Y35 is literally not available in India)

Thats all I can of for now ! let me know what you guys think and have to say about this !

Regards.

hi there,

for your first simulation of 32 mm t yoke y35(120x57x17) agh=2.5mm,

for that you need 32 awg bare diameter cu wire
aluminium former
vcid=32.50
winding height=12.04mm
winding outer diameter = 33.53mm
dc re= 6 ohm
force factor= 8.31 tm
xmax = 2.52



spl qe,qt,fs and vas will depent on spider and cone stiffness and mass of moving parts


ravs


be a vegeterian.....