[mlundy57]

I received the first 4 of the 8" non-servo drivers yesterday. I'm going to use 2 of them to build 2 of the single driver X-Subs.

Danny,

I a little confused about the dimensions in the X-Sub plans you posted. When I add up the seven internal height dimensions (254mm+12mm+19mm+12mm+19mm+12mm+19mm) I get a total internal height of 347mm. If I build the box out of 3/4" material that would add an additional 38mm for an outside height of 385mm.

The instructions say to increase the outside height to 397mm (additional 12mm or 1/2") to accommodate port volume. Where does this extra 1/2" go?

Also, how tall are the legs supposed to be to provide adequate clearance for the driver?

Mike

[Danny Richie]

I received the first 4 of the 8" non-servo drivers yesterday. I'm going to use 2 of them to build 2 of the single driver X-Subs.

Danny,

I a little confused about the dimensions in the X-Sub plans you posted. When I add up the seven internal height dimensions (254mm+12mm+19mm+12mm+19mm+12mm+19mm) I get a total internal height of 347mm. If I build the box out of 3/4" material that would add an additional 38mm for an outside height of 385mm.

The instructions say to increase the outside height to 397mm (additional 12mm or 1/2") to accommodate port volume. Where does this extra 1/2" go?

Also, how tall are the legs supposed to be to provide adequate clearance for the driver?

Mike

Yeah, over in China where those boxes were built they had odd sized metric measured MDF thicknesses. Making it out of 3/4" MDF will add a little bit of height and air space. It is a very trivial amount though and will have no real effect.

Just be sure and get the port size as close as possible.

If you down fire the woofer then it needs about a 2.5" to 3" tall set of legs under it.

[mlundy57]

Danny,

Thanks.

How important is the bottom plate? Would 2 1/2" to 3" floor spikes work by themselves or is the plate needed also?

Mike

[Danny Richie]

You don't have to use the bottom plate if you don't want to. Just let them fire into the floor.

[slosjo]

Just be sure and get the port size as close as possible.

I'm building a pair of these also.  A related question:
Can the vanes of the port be constructed out of 3/4" instead of 1/2"?
I have an overabundance of 3/4" pieces laying around but no 1/2".
Reducing the spacing by (math) inches could keep the length the same but would reduce volume.

[Danny Richie]

I'm building a pair of these also.  A related question:
Can the vanes of the port be constructed out of 3/4" instead of 1/2"?
I have an overabundance of 3/4" pieces laying around but no 1/2".
Reducing the spacing by (math) inches could keep the length the same but would reduce volume.

No problem. Just keep the lengths and volume of the port the same.

[mlundy57]

Instead of reducing the internal volume to accommodate the additional 3/4" of material (1/4" per piece x 3 pieces) could you increase the height of the cabinet by 3/4"?

By increasing the height 3/4" you would keep the volume of the box box itself the same (254mm x 279mm (10"x11")) and keep the port opening the same at 3/4". Seems like this would be the better way to go.

Mike

[Danny Richie]

Instead of reducing the internal volume to accommodate the additional 3/4" of material (1/4" per piece x 3 pieces) could you increase the height of the cabinet by 3/4"?

By increasing the height 3/4" you would keep the volume of the box box itself the same (254mm x 279mm (10"x11")) and keep the port opening the same at 3/4". Seems like this would be the better way to go.

Mike

Yep, yep, do it that way.

[ttan98]

Danny,

I am interested in a 8" non server sub, can you direct me to the spec., and cabinet design. I can't find it at your website, I assume it is rather new.

[Captainhemo]

Danny,

I am interested in a 8" non server sub, can you direct me to the spec., and cabinet design. I can't find it at your website, I assume it is rather new.

Here is the link Danny posted for the  box design
http://gr-research.com/pdf/X-sub.pdf

Last I heard  there wasn't a whole lot of  the non sevo 8" drivers left,  might want to call  Danny  soon  !!

-jay

[ttan98]

Here is the link Danny posted for the  box design
http://gr-research.com/pdf/X-sub.pdf

Last I heard  there wasn't a whole lot of  the non sevo 8" drivers left,  might want to call  Danny  soon  !!

-jay

Thanks for info, what's the spec., and price?

[Captainhemo]

The drivers  were recently  offered at $25 / piece.  Not sure on specs,  you'll have to wait for Danny to chime in

http://www.audiocircle.com/index.php?topic=112798.100



-jay

Post #103 

[slosjo]

These little drivers are quite a steal at $25 each.  Mine arrived yesterday and they are very nice. 
The whole assembly is very stout.  Rubber surround is very substantial and the cone is very sturdy (paper).

[Danny Richie]

Thanks for info, what's the spec., and price?

Specs:



Two left.

[ttan98]

Danny,

Thanks for the spec., looks like they don't meet my requirements.

[Danny Richie]

Danny,

Thanks for the spec., looks like they don't meet my requirements.

-3db ports is in the mid to high 20's. Not too bad...

[mlundy57]

These drivers look like they are designed to mount on the inside of the baffle. How do you do that so the driver will seal but not have the baffle opening rub the surround? There is only about 1/8" (with 1/16" of that being gasket) between the back of the mounting holes and the surround.

What type of clearance does the surround need?

Also, what type of mounting hardware would work best for this?

Mike

[Danny Richie]

These drivers look like they are designed to mount on the inside of the baffle. How do you do that so the driver will seal but not have the baffle opening rub the surround? There is only about 1/8" (with 1/16" of that being gasket) between the back of the mounting holes and the surround.

What type of clearance does the surround need?

Also, what type of mounting hardware would work best for this?

Mike

They don't mount from the back. I guess you could though. There is a gasket on the front side of the frame.

[mlundy57]

The gasket on the front side of the frame is intended to seal against the baffle, correct?

That puts the orientation of the gasket opposite what it is for say the M130. The M130's are designed to slide into the cabinet and the gasket seals against (and the driver is screwed to) the outside of the front baffle.

With the gasket on the front of the frame, these 8" woofers look like they are intended to mount to, and seal against,  the inside of the baffle. Which makes a lot of sense for a down firing application since the weight of the driver is supported by the baffle instead of the mounting screws/bolts but more difficult to mount since you would have to install the driver through the amp cutout.

My question is twofold. First, how to cut the opening (size, roundover, etc) so that nothing touches the surround but the driver will still seal given the tight clearences (1/8" total from the back of the mounting hole to the surround surface and only 1/16" of gasket)? and

Second, what type of hardware would work best, screws or threaded insert with mounting bolt?

Mike

[Danny Richie]

Actually those gaskets are typically installed on the front of those drivers for shipping reasons. Some even use a thick gasket to allow the woofer to be laid flat on the face.

If you want to mount it on that gasket though then you can. The through hole is the same. You can use a router with a circle jig to cut the through hole either way. You'll need to mark and pre-drill the mounting screw holes before assembling the box.

I would also recommend a slight rounding of the edge of the front surface.