DIY Sub .

siva, this is one project which i am going to be following with very keen interest ..most of them on dacs and amps are water over my bridge

how are you going to do the crossover in order to manage speaker integeration ? also would you plan line inputs from the preamp or high level inputs form the amp ?

Arj schrieb:

how are you going to do the crossover in order to manage speaker integeration ? also would you plan line inputs from the preamp or high level inputs form the amp ?

That's the best part ... no passive crossover to do any integration between the subwooer and the two-way (or MTM) speakers.

The natural roll-off of the two way speaker in the mids are just about sufficient. We then measure the FR and adjust the sub-woofer equalizer (which in turn will have an electronic crossover as well) to get the desired level of flatness....which is impossible in a conventional 3 way speaker with a passive crossover.

Well...all the above is my own theory, based on my understanding of physics (which is quite limited). Only time will tell !!

The subs will have only one channel input...directly from the preamp.

Hooray!
Lets follow this. What about the Shiva woofer?
Purnendu

purnendu schrieb:

Hooray! Lets follow this. What about the Shiva woofer? Purnendu

I thought Adire audio went under a while back...

Have you decided on your amp?

Having built a Sub sometime ago I think its worthwhile to consider a good quality plate amp.

I first built a Marchand Electronics mosfet amp coupled with their excellent active crossover. The amp and xo kit was imported from USA. A toriodal power transformer was custom wound by Miracle of banglore.

Putting together the amp, making a housing, getting an aritight fit, getting the amp stable etc etc were too much of an hassle. I gave up.

Now using the BASH Oaudio 500 watts plate amp. Its got all the controls that can possibly ask for. Continuously variable phase, notch filters, parametric equaliser, selectable subsonic filter. With a combination you can create any pole that you want

For the driver I am using Lambda Acoustics SB12. Again so kindly lugged all the way from USA by our good Bangalore buddy George Ollapally.

Again I will strongly recommend getting a plate amp

Should you guys interested than I will my post details in a new thread.

VERY fancy avatar aks07!!!
where did you find that tube girl??

AKS,

Checkout the following link, before u decide on a plate amp.

http://www.coldamp.c...d_amplifier_modules/

Also checkout Rod Elliot's solution for the xover...

Regards
Siva.

Hmmm DIY sub Siva. Well it all depends on the kind of bass you want. I would design one that works with my room boundaries rather than a text book perfect sub woofer. A H type open baffle is the easiest way with cheap 8" drivers, as they have figure of 8 pattern and can be judiciously directed to fill in the correct amount of SPL at the seating position. Wont go below 40, but a correct 40 is better than a bullshit inroom 50 in a box trying to do an inroom 30 .
I love maximising cheap drivers in my DIY so please excuse my lack luster input.
Deaf.

Great
This is one along with the TT project that I am going to follow.
It was a pleasure listening to the setup last Sunday Siva. Even without the sub, your setup extends quite low. But I guess you will need a sub if you want “ true full-range” extension. Hope your room will be able to support the lowest octave waves….

deaf schrieb:

Hmmm DIY sub Siva. Well it all depends on the kind of bass you want. I would design one that works with my room boundaries rather than a text book perfect sub woofer. A H type open baffle is the easiest way with cheap 8" drivers, as they have figure of 8 pattern and can be judiciously directed to fill in the correct amount of SPL at the seating position. Wont go below 40, but a correct 40 is better than a bullshit inroom 50 in a box trying to do an inroom 30 . I love maximising cheap drivers in my DIY so please excuse my lack luster input. Deaf.

Deaf,

I agreee with you fully. Infact it is the same philosophy that pushed me to make the sub amp on my own along with with L-R active crossover between the main system and the sub. I did not want to drive the drivers beyond FS and also wanted to rely largely on the sub's natural roll off. This way i get what the drivers are capable off...and nothing more.

I do have a big room in mind .. but room interaction related compensation will happen only after the initial version is ready.

Well Siva since you like doing the crazy and have the large room for it, here goes an idea. Make a pair of floor to ceiling line source subs using relatively inexpensive 8" drivers and mount them against the front wall. You will have a 2Pi line source, effectively minimising lobing errors and pressure and suckout zones. Now you can build a very good mid powered amp and go to extreme spl levels, as efficiency is nice to have.
Deaf.

deaf schrieb:

Well Siva since you like doing the crazy and have the large room for it, here goes an idea. Make a pair of floor to ceiling line source subs using relatively inexpensive 8" drivers and mount them against the front wall. You will have a 2Pi line source, effectively minimising lobing errors and pressure and suckout zones. Now you can build a very good mid powered amp and go to extreme spl levels, as efficiency is nice to have. Deaf.

Deaf,

Cool thoughts. I would love to try this...but i think i will most likely be thrown out of my own house.

However, since i intend to use a L-R active between the sub and the main setup, i'm hoping to minimize the lobing. Infact this was the primarily reason for me to take the sub route - rather than taking the conventional approach of a three way crossover.

Regards
Siva.

Dear Siva,
A sealed bass using a Classic Scan 10" paper carbon is also an option. A stereo set ought to do it.
Deaf.

Any reason why a Cylindrical design is not being considered ? i have heard only of the SVS and Hsu (in the past) with cylindrical designs. does this form have any disadvantages ?

Deaf,

I'm planning to use the Radiator 9" sub with the passive raditor. I feel this should be a better solution than a closed one. Yes.It will be a stereo set.

Arj,

Having non-parallel walls in a speaker cabinet is always an advantage...not only in sub. It is the logistics that makes it difficult...

Regards
Siva.

Dear Arj
They have only advantages and no disadvantages. I wont go into details as they are numerous, I will only say that the best material is cardboard much like car audio cylindrical subs.
Deaf.

Thanks Deaf and Siva.
Cosidering cardboard and Cylindrical shape, isnt this one of the easier sub to make once you already have a Driver and an Amp ?

I am asuming it cannot be a sealed box ( ?) but could a Bass Trap + Sub be an option in design ? where I am coming from is that corner placements might actually be a "2 birds with one stone" kind of a thing.

Arj schrieb:

Thanks Deaf and Siva. Cosidering cardboard and Cylindrical shape, isnt this one of the easier sub to make once you already have a Driver and an Amp ? I am asuming it cannot be a sealed box ( ?) but could a Bass Trap + Sub be an option in design ? where I am coming from is that corner placements might actually be a "2 birds with one stone" kind of a thing.

Dear Arj,

Same shape different purposes and hence different construction. But I will grant you that corner placement subs are the best. The only problem is the time relationship with the main pair. If that gets sorted out then everything is gung ho. Since we are in the cylindrical domain, the best subwoofer is the BOSE Acoustic WaveCannon, would love to make one.
Deaf.

deaf schrieb:

Dear Arj, Same shape different purposes and hence different construction. But I will grant you that corner placement subs are the best. The only problem is the time relationship with the main pair. If that gets sorted out then everything is gung ho. Since we are in the cylindrical domain, the best subwoofer is the BOSE Acoustic WaveCannon, would love to make one. Deaf.

Deaf, Wow.. this is something am doing some reading on it. Must say its very very male.


Frequency Range 25 Hz – 125 Hz Active Equalization (from 402TMC, 502®C or 802®C Series II systems controller) Required Nominal Impedance 8Ohm. Maximum acoustic output 115 dB-SPL average, 118 dB-SPL peak Maximum recommended amplifier power 600 Watts Sensitivity 90 dB-SPL (30 Hz, 1 W, 1 m) Enclosure construction Custom-extruded polyvinyl chloride Mounting points Four 12.7 mm-diameter (0.5") holes on two flanges Connectors 2-conductor spade lugs (barrier strips) Dimensions 3.81 L x 0.43 W m (150" x 17") Weight 29 kg (63 lb)

From what i could find out it costs about 4500 USD !!!

All specs talk of a 12" woofer and 12 feet in length and seems to be designed for conference rooms . i wonder, if a smaller one around a 8" would be possible..can "easily" be placed in a corner

I am sure with some ingenuity it can be disguided as a potted tree

You can also checkout the Tymphany LAT ..

The LAT is something you can give a shot at. Ok the best best sub is still as good as the room allows. So a pair of corner placed downward firing subs are the best bet.