Cloning the Okara - 2-way reference Speaker

[sunilj]

Thanks Harsha, let me try that.

Try this link for the completed pics

The Okara - a set on Flickr

Meet the 'Okara'

This is the finished speaker.

 

[t.antony]

Good job with the vinyl stripes.:thumbsup:

 

[Rajiv]

Hi,

Thank you for the detailed posts and pictures of the build.


Regards
Rajiv

 

[santhosh]

The Okaras look very neat in their Zebra finish Sunil. How tall are they when placed on the woofer?

Btw, Nice transformation on the room too, since I last saw it.

 

[anilva]

Sunil, great build and a very informative post as well.

Congrats. I am yet to listen to any of your stuff

Cheers.

 

[Gijo George]

That finish is a first and looks wild.
I see you haven't provided any bracing in the cabinet. Is it not required with the tar sheets provided?

Could you also give some details of the DIY LF cabinet like driver, amp, XO etc.

And please do give a brief description of the sound.
Thanks

 

[sunilj]

Anthony /Rajiv - thanks for the comments.

Santhosh,

The Okara's are tiny compared to other bookshelves. It was a challenge to fix the X-over inside that little cabinet. Before anybody asks....the volume of X-over components have been considered.

The volume is ~ 7.2 lt. The box height is 12.5 in.

Anil,

Anytime...over a 'Single'.

Gijo,

I got tired of the standard finishes and was keen to do something with my own hands. Spending money on the drivers and components makes sens but a lot can be done ourselves.

Regarding the shelving, such a small cabinet does not really require one. Also, remember these have been excluded from the responsibility of any music below 100hz. It makes a big difference overall.

Keep the questions coming. I was hoping to be a lot more detailed but lost the enthusiasm with the 'upload' limit. Somehow a link elsewhere and an explaination here does not cut it.

Regards,
Sunil

 

[cmsajith]

Similar to posting the pictures in HFV, you can do by copying it to imageshack and using the <IMG> ImageLink </IMG> to show the pics in the page itself.

Expecting a detailed thread...

 

[sunilj]

Where were we....

I'm a fan of braided Cat5, so used them for the X-over cabling.

The rear panel before adding the Anutone 'Synth' material. The foam is first rate for speaker filling, does not have any of the problems fibre-glass has and is very easy to use.

While mounting and tying down the X-over components, I made a mistake to have the 'clip' at the bottom. This is a no-no as I found out. Within the limited space inside it adds to the tkness of the board and you have to use a much longer screw to hold down the X-over inside.

In this photo, I've corrected the mistake and used a nail to make a hole so the screw can trace a path while tightening the X-over within the cabinet. It's a real pain to work within such a small space, but hey everything falls into one neat speaker without anything external. I know there are builders who go the path of keeping the X-overs external, so its your call.

A shot of the cabinet with the 'Synth'

For the speaker connectors I've used gasket foam around the edges so it makes an airtight joint. In ported systems it will make a difference.

The 'MX' brand speaker connectors. I've used them upside down so the connection does not strain the speaker cable.

The Vifa drivers.

Hex-nut used to close rear panel

 

[kaushik]

Very good progress , sticking to the thread for more ...

The cat5s do magic ,i tried them and they really help the units to get enough current for better SQ. Two main points they are cheap and OFC. We get the belden makes in 25Rs /pm,after stripping they give 3x the length .

 

[Gijo George]

Hex-nut used to close rear panel

Have you used just hex nuts or that with SH glue?
How many of those Cat 5 cables would you recommend in a braid? Plan to use them in case I run out of solid core cables supplied with the kit I bought.

That PVC connector is quite an idea coz it beats the need for soldering. Didn't have space to try it out in my XO.

 

[keith_correa]

Is that CAT5 braided? Looks twisted to me and not braided. Maybe I need to have my eyes checked

 

[santhosh]

Have you used just hex nuts or that with SH glue?
How many of those Cat 5 cables would you recommend in a braid? Plan to use them in case I run out of solid core cables supplied with the kit I bought.

That PVC connector is quite an idea coz it beats the need for soldering. Didn't have space to try it out in my XO.

Hi Gijo,
Since you have bought a kit (driver, crossover et all), I feel you should still stick to soldering. Unless ofcourse you want to keep tweaking with the components (like I know Sunil to be ).

Is that CAT5 braided? Looks twisted to me and not braided. Maybe I need to have my eyes checked

Keith, I too feel the CAT5 is twisted, but I am too distracted by an insect running on my monitor to be sure

 

[keith_correa]

That insect is IN my eye

If the CAT5 is twisted - it's nicely twisted. Does not seem done by hand. Drill twisted? Sunil?

 

[sunilj]

Is that CAT5 braided? Looks twisted to me and not braided. Maybe I need to have my eyes checked

Keith,

Quiet right, twisted, not braided....extended range :lol:

It was twisted by hand, very painful, but offset by what good internal heavy gauge cable might have costed.

Have you used just hex nuts or that with SH glue?
How many of those Cat 5 cables would you recommend in a braid? Plan to use them in case I run out of solid core cables supplied with the kit I bought.

That PVC connector is quite an idea coz it beats the need for soldering. Didn't have space to try it out in my XO.

Gijo, for the majority of the connections, they're all soldered. The 4 pair Cat5 is 16gauge and fits very tightly into the PVC connector which was the only reason I went that route....lazy basically.

Like Santhosh mentioned, stick with soldering, its an airtight joint.

The Final photos

Here are the final views.

This is my audio pad.

The power behind the speakers

The system is powered by my 'Super-Clone....tongue-in-cheek', for want of a better name.

Its a 6-channel gainclone, consists of:

3875 (BrianGT kit)
3886 (Designed by a friend & me)
4780 (Peter Daniel kit)

Its powered by 26-0-26@8A x 3 pairs of secondaries (1.2 KVa). The tranny is 8.5 Kg's and worth it. The total power at that secondary voltage works out to:

3875: 30/50w @ 8/4 ohms
3886: 32/62w @ 8/4 ohms
4780: 32/62w @ 8/4 ohms

The sound

I'm at a loss for explaining sound with superlative adjectives so will try to keep it simple.

The sound is beautiful and great to listen to. The highs are almost not-there, its just really really smooth ( I think this is described as 'silky' ). It can handle a lot of power and get incredibly loud. Perhaps this is due to the active x-over at 100hz.

Something I didn't expect but desperately wanted was a speaker capable of ALL kinds of music and this little bugger does it in spades. Whether you throw it D.Purple | Zappa | Tribal Tech | Jacques Loussier | Chic C. or Ravel, it just sounds good.

I've read dynamics are affected with higher order x-over (this one is 3rd order electrical). This is no slouch here either. Whether the drummer whacks the snare or beating the sh1t out of the bass-drum (RUSH) the Zebroid puts a smile on your face.

All in all, I'm happy, well worth the effort, bruised knuckles and fingers.

I've re-designed my bass-unit (the tall black box in the photos under the Zebroid). It was designed as a closed box which I later ported as a compromise. It will be redone in a properly ported enclosure.

Thats it folks. Thanks for looking & listening to my rant.

 

[denom]

Awesome work Sunil,

Really want to hear your speakers!!! Will PM you whenever I am in Bengaluru.

So whats the next project ???

 

[sunilj]

You're welcome anytime.

 

[Tarniel007]

Wiring a crossover

The crossover shown here is not of the Okara but I thought I'd put it here for others to see how easy it can be.

Pic 1: Start with a bare wooden sheet of MDF /Ply /Wood
Pic 2: Layout the components based on the crossover and wiring
Pic 3: Mark components and drill the holes for tying down
Pic 4: The connectors go in (not necessary to be done first...but I did)

I've never wired a speaker before. I bought the North Creek Okara 2 speaker hit and have no idea how to wire or set the omg connectors. Can you send me a pic or two on how you did this? I'm good at building computers so I thought I could do this to

You're welcome anytime.

Thanks

 

[sunilj]

Hi, old thread . Long gone.

The Okara's moved into this. A different design (P21) with D27 and P13 Vifa drivers. Text book copy. It was a 'BIG' difference and the speaker is with a friend.

Coming back to wiring the crossover - plywood, place your components, drill holes for cable ties and VOILA !. No real science there. There's plenty videos.

 

[sunilj]

The horn (Altec 802) is part of another system. The two 12" are just OB bass. Party sound , not really LOWww !