DIY Dome Tweeter ?

Finding a guy to machine all the parts is more than half the battle won.

Btw who is this guy ?

what material will u use for the dome ?

Manek

Manek schrieb:

Finding a guy to machine all the parts is more than half the battle won. Btw who is this guy ? Manek

Hi,

Thanks Manek for checking the thread !!

The Guy is my friends classmate ! has a SSI unit in Jalahalli Industrial Area (Near HMT and MSR Nagar) ! He is more then willing to take any turning orders !

Have got many things done from him ! all top notch work !!

what material will u use for the dome ?

I thought no one will ask !!

So here's goes it goes !

The Dome itself will be in all probability a Titanium,but I have some other types aswell like PEI,Poly,Silk,Fabric,Metal etc etc.....

So Am going to try all the variety and see which suits best !

Any other query or suggestion please do ask !

Hoping to see more participation from all the members !

Regards.

Hoping you would be able to maintain the close tolerances between both tweeters in terms of cutting, material uniformity, coils, etc.

Your turner friend is not in bombay I presume as those places don't ring a bell.

Magnets are ferrite or neodynum ?

Fluid cooled ?

Manek

Hmm a Bangalorean from the places you mention.
going to watch this with great interest.

Would love to know where/ how you are sourcing all the components and materials for the tweeters...

Thanks

Hi,

Thanks one and all for the interest shown !!

Manek indeed he's not ! coz Am from Bengaluru so is he !!

Yes I will have to and will make sure that the tolerances are maintained ! again like I said before,I've some things done from him and this is not an issue !!

Am sticking with Ferrite (F36 or the likes) as I have no source for Neo ! also working with neo is way different then the ferrite due to its size : power ratio !

I have different idea's and plan to use 2magnets for greater flux and such !

First I plan to check the performance without ferro and later add to see how things change !!

The components are all sourced locally ! there is a shop where he has promised me to supply with high quality magnet ! another fellow has some dome units,the metal will bought from local metal market where you get precut round pieces so that the turning is kept to a minimum.

I cannot/don't want to source them from abroad as it will devoid the whole purpose and make it as expensive or even more then the branded ones ! If so then the its no use me cribbing bout VFM !!

Please keep shooting all kinds of question (technical non technical ) !!

Regards.

Hi,

Guys update time !

I have just bought some of the components required for the unit !!

The basic Metal plates ( precut round ones )

The Domes (various types)

Here's the pics of the same !



The Magnets



The Titanium/Silk Hyrbid dome ( Top View )



Side Voicecoil View

http://lh6.ggpht.com...50778.JPG?imgmax=800

Bottom or upside down View

Here's the remaining stuff !

This is the PEI dome unit !

http://lh3.ggpht.com...50760.JPG?imgmax=800

Top View

http://lh3.ggpht.com...50769.JPG?imgmax=800

Side Voice Coil View

http://lh4.ggpht.com...50772.JPG?imgmax=800

Bottom or upside down View

As of now this is what has happened ! the plates will be turned and be ready in a day or two !!

Regards.

Looking good so far..

what is the impedance of the voice coil?..DCR of the wire being used?

What is the diameter of the voice coil?

Have you designed the base plate and basket?

Hi,

Savyasaachi schrieb:

Looking good so far.. what is the impedance of the voice coil?..DCR of the wire being used? What is the diameter of the voice coil? Have you designed the base plate and basket?

Ohh Yeah thats what Am talking bout !

The VC has Nominal Imp of 8Ohm while DCR is at aprrox 6Ohm (have to further test extensively to arraive at the exact value ! but more or less around that )

The VC is of normal 25MM dia !

Yeah the plates are already designed ! as you know there will not be any basket present (as its tweeter) the Dome unit will be directly mounted on the top plate of the magnet motor structure !

Now to some other details !

The face is a 3MM thick and 115 dia made from Aluminum ! which along with the plates will be turned !!

The Pole Piece will be vented and extended further beyond the bottom plate ! Am also planning to use Faraday ring ! but that has to be seen later !

Just a quick brief bout the stuff !

As always please do bombard with all the possible quires and suggestions !! Shall try to my best ability to answer them all !

Regards.

Any specific TS parameters you are gunning for ? If so how would you plan to achieve those ?

What would the sensitivity and the resonance freq be like ?

Hi,

Here's the details Manek !

The Targeted Fs is around 600-800Hz ( think as crazy of me as possible ) for some specific reasons which Am in a liberty to discuss at this point in time ! The Imp of 8Ohm with a DCR of not less then 6.the sensitivity will be around 88-90dB Range !

Now coming to how I plan to achieve it, I have some basic things worked out as mentioned below to get the desired results !

1)The pole pieces will be of 3 and 2.5 MM (bottom and top) ! Further the topplate will have a small champher (somewhat like a V cut ) near the Bore of the plate (the inner hole ) !

2)The Air Gap for the coil is around 1.5 (which is need for the desired Fs) !

3) the voice coil will have an extensive venting throughout,this will aid in cooling the coil in case I choose not to go with ferro or even otherwise ! This vent will also reduce the resonant frequencies developing near dome area ! Thus will help in achieving the said Fs

4) The pole piece will be vented ( 14MM ) and the vent will extended further beyond the bottom plate ! this again will help to remove any spikes in the response curve and will make it smooth !!

So these are plans that I have devised to get the results ! Although Am pretty sure of its workability will still not claim anything as of now ! the reason is I have not used any software to simulate the results ! as you all know these softwares costs something that I may be able to afford in my entire life ! so have instead taken some notes from various tweeters that I mentioned in the first post ! based on these notes have designed this ! Have tried to overcome the shortcomings of these by adding new features as mentioned above !

Hope this info is enough ! if not please don't hesitate to ask !

Regards.

Very ambitious on the fs but not on the spl :-) the tweeter should remain composed at the top end as well. How far do you want it to go at the top ?

how achievable is that low fs without simulators and other testing equipment I am not to sure but give it your best shot, I say.

The very best to you sir.

Manek

Hi,

Manek indeed its an ambitious target ! I have selected to bring the tweeters Fs this low for some specific purposes which I will tell at a later date ( please don't mind ) ! I have some theories to test after which I shall talk on this regard !

I have already said the methods for the same ! i,e to get the desired Fs I have mentioned what all the points I thought was necessary to achieve !

As with the highs,I think it should be in the range of 20-22K coz due to the very low Fs the design might not reach the 25K mark for obvious reasons ! so currently thats the projected topend range ! however I will test it and then post exactly the frequency response of this !!

Am very thankful and glad for the support that you and others have shown !!

Regards.

Hi,

Guys its Update time :yahoo: !!

I have finally got the metal pieces machined and ready for action !!

Here's the pics of the same !!

http://lh4.ggpht.com...8Q/s800/P1050478.JPG]http://lh4.ggpht.com...8Q/s800/P1050478.JPG

Top and Bottom plates

http://lh4.ggpht.com...U8/s800/P1050482.JPG]http://lh4.ggpht.com...U8/s800/P1050482.JPG

The Center Pole Piece

http://lh6.ggpht.com...Gg/s800/P1050486.JPG]http://lh6.ggpht.com...Gg/s800/P1050486.JPG

Center Pole Piece different angle showing the vent

http://lh3.ggpht.com...tE/s800/P1050488.JPG]http://lh3.ggpht.com...tE/s800/P1050488.JPG

Mock assembly of the Pole Piece and Bottom Plate