SoundLogic - ATMA

[Adhiraj]

Taking off from my last thread

http://www.hifivision.com/diy/8461-3-way-driver-selection.html

The new project has now been slightly modified hyeah:

to a 4 way active system.

Components being used on the driver front

LCY130 Ribbon Tweeters For the Highs
SEAS Prestige line MCA15RCY H1262 Coated Paper Midrange
BEYMA 10BR60 Woofer
2 x Hertz DS300 Subwoofers

On the electronics front I will be using

NAD c355bee As the pre amp and the power amp for the high section

Ebtech Line level shifter ,to convert -10dbv to +4Dbu

2 x DBX 234XL Pro Crossovers

2 x Crown XLS 202 ,one for the right mid and woofer and one for the left mid and woofer.Vertically Bi amping the midrange and the woofer sections

1 x Crown XLS 802 for powering 4 Hertz DS300 in Two Cabs (Stereo Subs ) in Sealed Isobaric Configuration.


Project Name

SoundLogic - ATMA

All components have been collected.

Now on to the build phase , will put up pictures of the components soon and follow up with the build once I get down to it :lol:

I would really appreciate ideas on loading the Midrange and its cabinet design and treatment.


Regards,

Adhiraj/SoundLogic

 

[Adhiraj]

I have finally managed to get around to building the subwoofer cabs for yes my Hertz "Car" subs , here are a couple of pics of the bracing and the cabinets , they are made out of club premium bwr aa ply , still unfinished as another layer of mdf is to be applied over the ply for a box in box concept , in between these two boxes will exist a layer of bitumen waterproofing felt (visco elastic 1 mm) .This should in theory work well as a Constrained layer damping system , which according to my research ( over the internetz) works best with a thin layer in between two plates of sinilar densities that are not coupled to each other by anything other than the layer and the glue. Initial tests (knuckle rap,ouch!) of just the ply cab with the bracing provides a very high pitched crack with no ringing , the cabinet seems quite dead already , things should only improve with the CLD (I hope) .

The bracing that you see is essentially non symmetrical , all the panels of the sub are of different sizes owing to the overlap butt joint system I have used , hence each panel has a different resonance characteristic , the bracing is offset using the golden ratio .The cabinet bracing is mirror imaged in its offset for the pair . In addition to the bracing you might notice a blue panel , containing a special sound absorbing / back wave scattering mat jointly developed by me and 3m/dupont and is proprietary hehehehe .
There will ultimately be two woofers in each cabinet in a face to face push pull isobaric configuration , this is done for three main reasons
1) Space used is half that of one woofer
2)In a push pull (where one woofer moves out and one in) distortion is lowered .
3)Its just a cool concept , hehe .

Things I am giving up include 3 db spl because they are wired in series , but hey I have two cabs , stereo subs so I guess I make it up there . Using these car subs have a few problems , they dont handle all that much power before reaching excursion limits , but I am listening to music only so very little sub 30 hz content anyway .

Hoping to get them absolutely done in a few days , more pics to come

 

[Adhiraj]

By SoundLogic at 2011-02-21[/IMG]

 

[Adhiraj]

Sorry for the bad image quality , I didnt really feel like breaking out the slr

 

[Adhiraj]

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[Adhiraj]

A couple of more changes to the initial plan , I will now be using Crowns Class D power amp the XLS1500 for the subs instead of the old XLS series ( I can just see it now , all the audiophiles rolling their eyes ,"he is mixing 'pro' audio with 'home' audio and 'car' audio" hehehe )