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GR Research OB7, N3S and AV1-RS build

Wharfedale Linton Heritage Speakers

baswamin

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Jul 11, 2011
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bangalore
Hello all,

First of all, this build would not have been possible without the brilliant effort of Captain and a BIG thank you to him for pulling off the group buy.
I had procured the speaker kits through the mega group buy organized by Captain and have started the build of these kits.

I had passed along the drawing that comes along with the kit to my cabinet builder to get started. He called me on Friday (10/12) and told me to get some sample speakers and suggest any changes if needed. I was told it was a mock up using scrap wood panels (left over from other projects) since these guys had not built anything like this earlier. When I went there I was thinking it will be rough mock up. But to my utter surprise, these guys have built exact replicas. :clapping: Big kudos to them for this effort.

Anyway, I have given all the feedback necessary and they will be starting the build soon. It may take some time to get it finished since this is holiday season with Dasshera around the corner. I am hoping we can get it done before Diwali, but this is not sure. Some pics are attached.

ImageShack Album - 5 images
 

jls001

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Feb 9, 2010
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Nicely shaping up.

Please use bracing wherever possible to make the cabs more rigid.
 

iaudio

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Are these the photos of mock ups in the imageshack album? If so, the final product finish is sure to be phenomenal!
 

baswamin

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Jul 11, 2011
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bangalore
Nicely shaping up.

Please use bracing wherever possible to make the cabs more rigid.

Thank you for the comments. Yes, bracing will be used as indicated in drawings provided. Since this is a mock up and they had some doubts regarding the bracing in X-LS encore, they had not fixed it. You can also notice the dovel joint in the pic where the front panel is removed.

Are these the photos of mock ups in the imageshack album? If so, the final product finish is sure to be phenomenal!
Yes, these are mock up photos. Hope the final finish will be good.

Congrats on your build Baswamin. Is the MDF pre-laminated on one side?

MDF is not laminated, there will be veneer applied on top. The front panel will be painted black with semi gloss finish (so that maintenance is not very difficult) and the sides of the cabinet will be veneered. It may look similar to this.
A sample of veneer that will be used along with painted panel is shown here.
Veneer and panel

Nice going! Best of luck for a speedy build...
Thank you for the wishes.
 

Danny Richie

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Sep 6, 2011
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Iowa Park, Texas
Looks good.

I can't really tell in the pics but thought that I would remind how important it is to add a radius to the back side off all woofer through holes. Otherwise the diffraction effects of the back edge will disrupt the response.

This of coarse is for the small woofers, not the sub.
 

exljp

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Aug 23, 2006
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Looks good.

I can't really tell in the pics but thought that I would remind how important it is to add a radius to the back side off all woofer through holes. Otherwise the diffraction effects of the back edge will disrupt the response.

This of coarse is for the small woofers, not the sub.

I am not able to understand what Danny says here, can someone explain further?
 

Rgn1

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Sep 10, 2011
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I had similar Questions as well :)
Take a look at the link to N3 build pics posted by Surrealistix below.
Should give you a fair idea.

But if this is not what Danny meant, do let me know too :eek:

Edit:
Added G0bble's post which I think explains the need, but again correct me if I guessed wrong.

~Cheers!

Hey guys, could you please post a snaps of the front baffle of the speakers showing the radius that Danny had mentioned on the inner side of the woofer hole? It would really help.

Does the radius and round over mean the same thing or are they different?

Also, is a similar radius or round over required for the front baffle of the subwoofer as well?

And if we choose to double the thickness of the subwoofer cabinet walls, would we need to change the dimensions of the radius or round over of the inner side?

Thanks!

Thanks, I meant what Danny mentions here in Magma's LS-Encore build:
X-LS Encore Build from India


I am not sure if that is applicable to N3 as well. I am guessing Danny means for us to have a round over and/or radius (I don't know the difference :() of the inner side of the woofer hole, so was looking for confirmation of that and some snaps if it had been done by some of the early starters.

Cheers!

Yes, I think this rounding over is very critical: http://gr-research.com/pdf/X-LS Encore box.pdf

Here is how it's done for the N3.

speaker build 33

Here is a link - chamfering driver holes

Snake oil with masala and all ... :)

--G0bble
 
Last edited:

jls001

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Radiusing refers to this?

 

sbg

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Dec 28, 2009
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What he means is Chamfering the inner side -as I understand.

Danny had been stressing this at almost on all the builds

http://www.hifivision.com/diy/28409-cabinet-build-gr-group-buy-kits-4.html

speaker build 33
Speaker Build 63
check how rounded is the innder side of the woofe hole

Paul Carmody's - SPEEDSTER build thread - Page 2
check posts not 30 and 35 - Chamfering the inner side of the woofer hole
-- this couold have been a half inch radius cut on the
inner side to woofer hole instead of leaving it straight edge.

Giant Killer build - Page 5 - Home Theater Forum and Systems - HomeTheaterShack.com
Giant Killer build - Page 8 - Home Theater Forum and Systems - HomeTheaterShack.com
post #77

hope this helps
 

baswamin

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bangalore
I think sbg's post with pic "speaker build 33" shows it clearly. In that pic, the right hand side baffle shows the back side where as the left hand side shows the front side. On the back side, the openings for woofers have their edges rounded. This is to avoid diffraction of sound which is high at sharp corners.

Thanks
 

baswamin

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Jul 11, 2011
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bangalore
GR Research OB7, N3S and AV1-RS build: Crossover build

I started to build the crossover for the speakers. Last time I visited my cabinet builder, I also got some pieces of wood on which crossover would be built. I dont know what type of wood it is but looked strong enough to hold all the components. The dimension of these pieces were based on the available space within each cabinet. Based on Danny's tutorial on audiocircle, I started the assembly. Few snaps attached below and I think they came out ok.

Now, I need to solder the joints and connect the wires. But before that, I will start OB7 crossover and get it to this stage. It is the most complex cross over of the lot and hence I kept it for last.
 

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baswamin

Active Member
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Jul 11, 2011
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Location
bangalore
OB7: I have to still get the boxes for the cross over of OB7 completed. I thought the exterior of this cross over box can be any finish but it looked ugly with the finished speaker. I should get it in couple of weeks. Anyway, I dont yet have a good amplifier to drive this speaker. Amplifier build is also half way through. So, still some way to go before I finish everything up.

N3S, AV1RS and Servo Sub: These are ready and are being driven by Marantz receiver (along with OB7).

Initial impression is that the Neo3 tweeter is really really good (even with the receiver), so I assume it will be very good with a good amplifier. I cant describe the sound in audiophile terms but the sound from Neo3 tweeter is very detailed. The midbass drivers are also very good, I had the M130x in lower half of OB7 and produces good bass. I dont have any other reference to compare with, so not sure how it compares to other good speakers.

Anyway, I am pretty happy till now on how the whole thing sounds (considering I dint have anything good system till now). Captain, thank you again for your herculean effort. I have attached only couple of pics for now (N3S was not finished when these snaps were taken).
 

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harsh247

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Sep 23, 2010
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kolkata
looking good!
i have sent my x stats and voce and encore for finishing. should get it soon.
i did hook em up to listen to them. the stats are brill. i can imagine what the ob 7's will sound like!
 
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