[Hank]

Excellent build there, Peter!  Tile is a nice touch.  And, you're certainly using the corect brand of contact cement and painter's tape

[edoggrc51]

Hi all, the second set in this thread is for sale here:

http://www.audiocircle.com/index.php?topic=115384.new#new

Just replied to your thread. 

[rajesh]

I'm the guy on the Indian DIY group who had organised a group buy of GR Research speaker kits. Also, I'm (most probably) the last guy on the group to have taken up the build. Was going through the builds and found that Peter has documented the build of all the speakers that I'm making and documented too well. I have a few queries; hope Danny, Peter or others could comment.

Doesn't this additional layer of 19mm MDF increase the height thereby altering the response from what's the designer intended?

I'm resurrecting this because it's essentially the same speaker setup with a different finishing twist.

I can see that the X-SLS are rear ported. I remember reading one of Danny's post where he had stated that the port could be shifted to front too, which is what I too am thinking of to enable me to push the speakers closer to the rear wall. If it could be front ported, I'm wondering where on front should the port be located? Bottom, (Above the space at the bottom for filling the ballast) Top or in the middle!

[persisting1]

rajesh, I'm happy to read that you have yet to build your kit. I now have company    With that said, I need to get to work on a few project Hope it turns out well for you.

[Peter J]

I'm the guy on the Indian DIY group who had organised a group buy of GR Research speaker kits. Also, I'm (most probably) the last guy on the group to have taken up the build. Was going through the builds and found that Peter has documented the build of all the speakers that I'm making and documented too well. I have a few queries; hope Danny, Peter or others could comment.

Doesn't this additional layer of 19mm MDF increase the height thereby altering the response from what's the designer intended?

I can see that the X-SLS are rear ported. I remember reading one of Danny's post where he had stated that the port could be shifted to front too, which is what I too am thinking of to enable me to push the speakers closer to the rear wall. If it could be front ported, I'm wondering where on front should the port be located? Bottom, (Above the space at the bottom for filling the ballast) Top or in the middle!

Hi rajesh, you dug up an old thread here, glad to know they're of some help still!

 To clarify, the reinforcement I added to bottom was plywood, not MDF. I can't imagine the additional 1/2"(12mm) in height would make appreciable differences in speaker performance. One could gain or lose similar amounts in adjustment of the bottom spikes or simply slumping down in your favorite listening chair 

As to port positioning, I suspect putting it in lowermost area of cabinet (above ballast compartment)  would be best, but I'll let Danny speak to that. Also, I know Danny has recommended moving transmission line exit on N3 from rear to front, but unsure if he's mentioned it for this model. My gut says it'd be fine, but best let him confirm.

[Danny Richie]

Yeah, plus or minus a little height is no different than variations in seating height.

Moving the port to the front is also fine. Just put in in the same plane just moved to the front panel.

[rajesh]

Thank you Peter and Danny. I'll take it up accordingly.

@persisting1, just do it.

[rajesh]

As I keep progressing, I'm encountering new challenges. I'm posting them here as this thread has documented the build of all the speakers that I'm building too. Hope OP doesn't mind my posting queries here.

I've noted that a few members have made baffle twice as thick as the rest of the box by affixing two 19mm sheets which can loosely be termed as double baffle IMHO. In India, we get only 18 mm sheets. Many members of that Indian group buy have made X-LS speakers with double baffle which I personally consider an overkill. However, since the X-SLS is much longer, I found the double baffle to be a great idea and hence have fabricated the same by affixing two 18 mm sheets. (I've also remembered to do some chamfering of the inner sheet.)

Now my query is, does this double baffle thingy is necessary for the X-CS and A/V 1RS too or would it be an overkill (especially for the A/V 1RS) As per my perception, since the X-CS has two mid-woofers, double baffle may be of some relevance.

Soliciting comments from Danny, Peter and other experts. 

[Peter J]

Rajesh, my understanding of "double thick" baffles is that it's another way to damp and stiffen cabinet. The only negative effect I could imagine would be the longer "tunnel" created behind drivers. I suspect it would be no issue on tweeter, more likely with woofer.

Could one hear the difference with thick baffle in this design? I kinda doubt I could, but my hearing's not all that great...funny I chose this hobby, huh? One thing I can tell you about Danny's cabinet designs is that they're well braced, which in and of itself helps to damp the enclosure. Couple that with NoRez and I haven't felt compelled to add to 'em.

All that said, I'd defer to Danny for what effects thick baffle might have on design.

[Danny Richie]

Additional baffle layers are not necessary with these designs.

Unlike other types of woofers these woofers do not require additional material to be removed from the baffle to flush mount the driver. Also, the polymer frame is non resonant and will not transmit a resonance to the front panel like most metal frame woofers.

If additional baffle layers are used then it is important to increase the back side radius behind the woofer.

[rajesh]

Read this thread on my Android phone and thought of replying later as it is too painful to type with my thick fingers and forgot to reply. 

Thanks for the reply Peter & Danny. Wish I had posted the query before fixing the baffles. I could've saved some wood. Nevertheless, it certainly helped in making up my mind with regard to baffles for the Centre and surrounds.

[rajesh]

If additional baffle layers are used then it is important to increase the back side radius behind the woofer.

I've just finished all the boxes but the back side radius behind the woofer (chamfering) of the towers remains which I intend to do this weekend. That brings another doubt in my mind. Is this chamfering required behind the woofers of X-CS, A/V 1RS and that of the Servo Subwoofer also?

[Danny Richie]

I've just finished all the boxes but the back side radius behind the woofer (chamfering) of the towers remains which I intend to do this weekend. That brings another doubt in my mind. Is this chamfering required behind the woofers of X-CS, A/V 1RS and that of the Servo Subwoofer also?

You should always radius the back side of the through hole on all but sub-woofers. The wavelengths that the sub-woofer plays are too long to matter and won't even propagate in the box anyway. However, rounding the edge on a sub-woofer can in some cases prevent air turbulence in that area of the box. So it doesn't hurt. 

[rajesh]

You should always radius the back side of the through hole on all but sub-woofers. The wavelengths that the sub-woofer plays are too long to matter and won't even propagate in the box anyway. However, rounding the edge on a sub-woofer can in some cases prevent air turbulence in that area of the box. So it doesn't hurt.

I was attempting a 45° shaving off at the rear but if it just needs to round off, that would be easier I guess. Let me discuss with my carpenter.

[lacro]

I was attempting a 45° shaving off at the rear but if it just needs to round off, that would be easier I guess. Let me discuss with my carpenter.

Rajesh,
To cut the radius after the cabinets are assembled, your carpenter would need this router bit. The photo is from Peter's build.

[rajesh]

That's nice of you Lacro. 

Though in a different league as far as price is concerned, the finish of this Focal Sopra Speakers is so outstanding that I wish I can do the same way of making grills to cover just the drivers. But won't those recesses around the drivers degrade the sound?

[Danny Richie]

The two lower drivers in that speaker are not playing up high enough for there to be any reflection issues off of the recess. The upper one is a mid-bass driver though. So there could be some issues there. And with the grill on there will be some edge reflections (worse) from the edges of the grill frame.

[rajesh]

Point well taken Danny. Thanks.

I can see that the X-SLS are rear ported. I remember reading one of Danny's post where he had stated that the port could be shifted to front too, which is what I too am thinking of to enable me to push the speakers closer to the rear wall.

Moving the port to the front is also fine. Just put in in the same plane just moved to the front panel.

I've noted that a few members have made baffle twice as thick as the rest of the box by affixing two 19mm sheets.

since the X-SLS is much longer, I found the double baffle to be a great idea and hence have fabricated the same by affixing two 18 mm sheets.

I wish I could go with Danny's design in toto. Because I deviated a little, I'm facing new problems, this time regarding placement of the port.

Since I had made a thicker 36 mm baffle, I now realise that if I were to shift the port to the front, the port tube would move out of the box by 18mm (Though the port length per se would remain the same)

Will that have any adverse on the performance of the speaker? If so, I'll proceed with the original design (of keeping the port at the rear)

What say folks?

[Danny Richie]

I am not sure what you mean by the port tube moving out of the box.

Unless you are placing the speakers right up against a wall then I would keep the port in the rear.

[rajesh]

I am not sure what you mean by the port tube moving out of the box.

Unless you are placing the speakers right up against a wall then I would keep the port in the rear.

Since I added 18 more mm on the baffle and since the port has to be now fixed over that additional MDF plank, I described it as port moving out of the box (to the tune of 18mm)

As for the placement, since I do not live in a permanent house as yet, I don't know how they are going to end up with. Hence I wanted to keep the option (of placing it right up against the wall) It's not a deal breaker though. If the port placement on the baffle poses a problem, I would happily settle placing it at the rear.