Need help/guidance to make cabinets for GR Research X-ls encore kit

AmitKumar

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Sep 27, 2010
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Dear FMs,

Few months back after reading a lot abt the GR Research kit in our forum, other hifi forums and after talking to few FMs who are using them i got interested in buying the X-ls encore kit from GR Research. Before making the final decision i interacted with FMs Capt. Rajesh, Mishra Ji and Bibin. I am very much thankful to them for their advice and guidance. FM Manniraj supported me a lot in finalizing this decision and i am very thankful to him too. I am sorry if missed any name as i might have discussed with more FMs. After deciding on this kit i even posted a wanted thread to buy the mentioned kit but i could not get my hands on the same. So towards the end of last month i decided to import the the kit from US. A generous friend arranged for a hand carry of the kit to india from US. I received the same day before yesterday, i checked the contents and everything seems to be in order.

Now the next part starts, that is building the cabinets for the same. Due to real estate constraints i can only make bookshelf speakers out of this kit. My experience with the DIY is zero, infact i have never even tried soldering a wire. I need your help and guidance on making these cabinets or getting them made from somebody who can do this for me partly or fully. I have tried to divide this into following points where i will be really thankful if i can get some ideas/guidance:

1) I wanted to check with the DIY experts if there is a possibility of making front ported bookshelf speakers from this kit instead of going with the original plan of back ported ones without making any change to the cross over. I read somewhere Danny mentioning that these can be made into front ported speakers also, The same is mentioned in the beginning of the following thread:

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An FM and a great friend has advised me to stick to the original plan given by GR Research, but i still thought to check with you guys before making final decision.

2) The second part is related to the actual building of the cabinets and assembling of the kit. i have further tried to split this into following:
a) I think the cabinets will take about half of a mdf sheet. Is it possible to buy a half sheet of the mdf or not. If Bangalore FMs know somebody who sell half of the mdf sheet then it will be a great help. Otherwise buying a full sheet is the only option.
b) Once MDF sheet is acquired then i need to find somebody who can cut it for me as well as assemble the cabinet. now this can be by the same vendor or two different vendors. But how do i find those vendors.
c) Third part is assembling the kit into the cabinets and testing them, for sure i need help and guidance from FMs from Bangalore especially.
d) Once the kit is assembled and tested then i need to get the cabinets veneered with the 3mm veneer also known as decorative ply. I think this can be done by the same person as of point b. though not sure.

I request all the DIY Enthusiasts/Experts to help me with this DIY project.

Waiting for your valuable guidance and support.

Regards, Amit
 
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I read somewhere that ibin has some unfinished cabinets. May be you can check with him.

Even my 5.1 kit is lying on the attic begging me to get them out from there. :)

Now finally I've been able to locate a guy here in Chennai who makes office furniture actually and who is an audio enthusiast and has a workshop with CNC router, pressing machine, edge banding machine, rounding machine et al.
 
I read somewhere that Bibin has some unfinished cabinets. May be you can check with him.

... who is an audio enthusiast and has a workshop with CNC router, pressing machine, edge banding machine, rounding machine et al.
+1. That looks good option. Bibin has it. So why to reinvent wheel? If that known to me earlier I could have gone that way. In fact still you can get DIY fulfillment by fitting all by hand.
Making the correct box is very time consuming if you don't have tools, resources and time.
 
If you go the cabinet building route, some pointers:

1) For front and rear baffles you can use two layers of 18 mm.

2) If you want to go even further this route, you can make all baffles of 18 mm x 2 layers. Do maintain inner dimensions strictly.

3) Bracing is very important

4) Bitumen sheet is useful for dampening the inside of the cabinet. You can use acoustic foam on top of the bitumen sheet. Then use glasswool or synthetic fiber to fill the cabinet.

5) Rounding the woofer hole from the inside is important

6) Don't play around with the porting unless Danny has given specific drawing for front porting.

7) Plywood shops usually have MDF. It shouldn't be a problem finding suitable MDF.

8) CNC cutters will give you correct dimensions.

9) If you have decorative veneer in mind, do take into consideration its thickness.
 
1) For front and rear baffles you can use two layers of 18 mm.

2) If you want to go even further this route, you can make all baffles of 18 mm x 2 layers. Do maintain inner dimensions strictly.
2x18mm is IMO overkill and unnecessary. At most I would go 1" thick. And why 2 layers? What would be the benefit?

4) Bitumen sheet is useful for dampening the inside of the cabinet. You can use acoustic foam on top of the bitumen sheet. Then use glasswool or synthetic fiber to fill the cabinet.
Correction - use glasswool or acoustic foam over the bitumen sheet to line the cabinet.

The back of the woofer cutout should be angled at at least 45 and not just rounded in order not to suffocate movement of the cone. This becomes even more critical when the front baffle is thicker.

Danny also recommends angling the inner perimeter of the grille frame (if a grille is used).
 
2x18mm is IMO overkill and unnecessary. At most I would go 1" thick. And why 2 layers? What would be the benefit?


Correction - use glasswool or acoustic foam over the bitumen sheet to line the cabinet.

The back of the woofer cutout should be angled at at least 45 and not just rounded in order not to suffocate movement of the cone. This becomes even more critical when the front baffle is thicker.

Danny also recommends angling the inner perimeter of the grille frame (if a grille is used).

Most of the DIY kit cabinet plans that we get like mine Zaph audio and GR Research suggest to use 1 and 1/2" MDF panels but here in India we get only 3/4" MDF (which is roughly 18 to 19mm thickness). Hence to achieve that doubling of the 3/4" MDF is the only option. I have also used double layering of 2 MDF sheets by maintaining the internal volume. It has made my cabinets very sturdy and as per the specifications. I believe it does not harm and as far as I have seen/heard there is no draw backs of doubling.
 
You get 1" MDF here. And, yes using thicker will do no harm but IMO, provide no real benefit too in cabinets this small especially when they are going to be damped. Sub enclosures are a different matter though.

And a little OT, but I read once that the best and most effective form of bracing is to pull the walls to be braced with a little tension. Suggestions on how to easily achieve this is welcome. Eyelets on opposite sides with long cable ties through them and tightened?
 
You get 1" MDF here. And, yes using thicker will do no harm but IMO, provide no real benefit too in cabinets this small especially when they are going to be damped. Sub enclosures are a different matter though.

And a little OT, but I read once that the best and most effective form of bracing is to pull the walls to be braced with a little tension. Suggestions on how to easily achieve this is welcome. Eyelets on opposite sides with long cable ties through them and tightened?

I agree to Keith, using 1" or 1.5" baffle will not make much difference in such small dimensions. However for Sub and FS enclosure 1.5" or above is the min. requirement.

For bracing, lining the internal walls with ceramic tile is an alternative as it won't eat up much of the internal volume and is cost effective too. Using Araldite, it can be very easily glued to the internal walls.

Thanks,
Bibin
 
+1. That looks good option. Bibin has it. So why to reinvent wheel? If that known to me earlier I could have gone that way. In fact still you can get DIY fulfillment by fitting all by hand.
Making the correct box is very time consuming if you don't have tools, resources and time.

As of now this seems to be the best option for me if i am going ahead with the original drawings given by GR Research. I will probably discuss with Bibin on this once i finalise the porting part.
 
I am not sure if the 25mm mdf is available or not. I read at most of the places that 18mm is the one which is widely available. If 25mm is available then it is probably better to make the whole cabinet with the 25mm mdf only, however one need to cut the mdf carefully to ensure that the internal volume is not compromised.

Other option may be to sandwich a 18mm mdf with 6 mm mdf or ply.

Dear Friends

Please give your view on the point number 1. that is making front ported enclosure.
 
in India we get only 3/4" MDF (which is roughly 18 to 19mm thickness).
25 mm MDF is available in India. I saw a sample at the workshop I talked about in my earlier post.
For bracing, lining the internal walls with ceramic tile is an alternative as it won't eat up much of the internal volume and is cost effective too.

I'm not sure what how we can achieve by lining the internal walls with ceramic tiles.:confused: Since one of their sides are glazed, IMO it would increase standing waves inside the cabinet rather than absorbing.
 
2x18mm is IMO overkill and unnecessary. At most I would go 1" thick. And why 2 layers? What would be the benefit?

Two layers because there is no 1-and-half inch sheet available. Thicker because it is much more rigid. And more damped, too. In fact using two layers glued together properly (inadvertently) provides is constrained layer damping. I think there are benefits even for a small bookshelf. Of course cost and effort goes up.
 
25 mm MDF is available in India. I saw a sample at the workshop I talked about in my earlier post.


I'm not sure what how we can achieve by lining the internal walls with ceramic tiles.:confused: Since one of their sides are glazed, IMO it would increase standing waves inside the cabinet rather than absorbing.

Yes captain, I agree that it is available but most of the stores do not stock these 1 and 1/2" MDF boards and the fast moving is 3/4" only. I inquired almost 15 to 20 stores and nobody had this 25mm MDF. But some of them were ready to get it especially for my need but the cost more than doubles up. Hence I decided to sandwich 2 pieces to get the panels done and I am happy with the outcome.
 
Hey guys,

A couple of things.

Porting out the front is only possible if building the small floor standing version.

http://gr-research.com/pdf/X-SLS Encore box.pdf

There is no room on the front baffle for a front port on the mini-monitor. You can however move the port to one of the sides. I would only do this though if the speaker has to be placed right up against a wall.

On thicker walls and baffles. This is not at all necessary with this design. 3/4" or 18mm material is fine.

The reason many speakers need a thicker front baffle is that most woofers require material be removed from the front baffle in order to flush mount them. And metal frame drivers tend to transmit resonances to the front baffle.

The M-165 woofer surface mounts without removing any material from the baffle. So the full thickness is maintained.

Secondly, the polymer chassis doesn't ring or resonant. So resonances are not transmitted to the front baffle.

And if thicker baffles are used then the radius to the back side must also be increased. An inch and a half thick baffle for instance could really use about a one inch radius. And you'd run out of front baffle width with a radius that big.

The bracing will take care of the rest of the cabinet walls. No Rez or any other damper placed on the inside walls is also a plus. The more solid the cabinet is the better.
 
Two layers because there is no 1-and-half inch sheet available. Thicker because it is much more rigid. And more damped, too. In fact using two layers glued together properly (inadvertently) provides is constrained layer damping. I think there are benefits even for a small bookshelf. Of course cost and effort goes up.

+1 and my BS are so heavy that I am hesitant to carry anywhere for audition even in my car. They do not shake even at high volume and gives good feel to the sound.
 
Thicker because it is much more rigid.
I agree.

And more damped, too.
I disagree.

In fact using two layers glued together properly (inadvertently) provides is constrained layer damping. I think there are benefits even for a small bookshelf. Of course cost and effort goes up.
Joshua, if that were true, plywood would be already be conforming to the CLD principle. But it does not. The damping layer should be some sort of a viscoelastic material.

If I really needed a Q&D CLD solution, I'd layer 18mm MDF with 5mm MDF [5mm on the inside of the cab] with the thinnest rubber sheet I can find as the damping layer between the 2 MDF layers. Any shop that sells baby products sells rubber sheets - it is actually fine fabric sprayed with rubber. Should work fine. Hell, lets go anal and layer three 5mm layers with the rubber sheet between the 3 layers. I bet it would be killer!!!.
Bibin, you want to try this for Amit's cabs? :D
 
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+1 and my BS are so heavy that I am hesitant to carry anywhere for audition even in my car. They do not shake even at high volume and gives good feel to the sound.
I've used 0.75" MDF for small floorstanders [with bracing] and they are fine there too. Horses for courses.
 
I'm not sure what how we can achieve by lining the internal walls with ceramic tiles.:confused: Since one of their sides are glazed, IMO it would increase standing waves inside the cabinet rather than absorbing.

We have to use damping material over the tiles to overcome the reflections. The kind of glue (silicon based) used for stick the tile is also important here. This makes the enclosure walls really solid and reduces the vibrations.

Thanks,
Bibin
 
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