I know andrew made the modification where he had the hatch as the whole back panel and I think he found it worked fine.

I think replacing the curve with mitred angles will ruin the sound of the cabinet unless you completely redesgned it. The curved section is actually not too difficult to do, its just hard work and time consuming.

I'd suggest reading Dom's step-by-step build for the HD15 on speakerplans.  I'm sure the curved section isn't as difficult as you think.  It's just the waiting for each layer to set...

(says he, never having touched a sander!!  )

Personally I think if you haven't much experience then you'll be much better off building the curved section, as all you have to do is bend the wood.  The only thing is waiting for the layers to dry.

Much easier than cutting accurate mitres if you haven't got a table saw...

I hadn't got any carpentry experience when I built my first hd15 cabs so just give it a go...

Hi,

Just wondering, do you have to use thin layers of wood for the curve, or is it possible to bend an 18mm sheet by steam? How about when using MDF?

Cheers

Jamie

The best driver to go with, if you are only going to use 1 is the P-Audio BM15LF, and its cheaper too. You would be ok with 360watts going into it, although ideally you would want 500 - 600 watts.

Jamie

The best driver to use in bigger stacks is the P-Audio C15-500LF, which is little over £100. The PDs are excellent drivers, but you need a lot of power to run them properly.

Jamie

The removeable back approach has still to get the Rog 'seal' of approval.  One day, hopefully at the Soundoff, Rog will be able to compare HD15 units built in different ways.

My approach is to glue/screw the four sides and baffle, and then start on the curved section using load straps to hold the wood down.  Would definitely recommend doing the curved section rather than a load of mitres.

Having a removeable back enables a top hat to be bolted in where the door is on the plans.

Also, I tend to use a tube of Gripfill per cabinet, mainly to glue down the first curved section from the inside, and thereafter any other inside edge, including the baffle.

The first unit I built, the curved section was made from 2mm MDF, nice and flexible, with lots of thin strips, like a roller blind/door, effectively lots of mitres, between layers.  Would definitely go the thin ply route, but the first layer is a bit tricky to bend.  Thereafter you just need to ensure that there are no air gaps between layers.

the curved section can be done in 20 minutes. Just create curved guide rails down the sides to screw too. Then glue one side of all 5/6 pieces. Screw them all into the bottom, and start bending by screwing into the guide rail ever 2cm. Worked great, we have a perfect curve with no problems. Took 2 days to build 4!

Have e-mailed the construction pic to Rog but he has yet to put them up...

Specs for most drivers are on the www.  Rog likes access panels as small as possible to improve rigidity.

The access hole for the driver ends up on the top of the unit, which makes it look a bit messy (with my carpentry anyway).  However I've not built it dom's way, with leaving the bass (top in the diagram) off until the end of the build.

My back panels are stiffened a little with an additional layer of ply glued down on part of the back to help support the speakon connectors.

Good luck with the build.

doing the curve is easy

when Dom and i did ours we had the individual sheets over sized so that they all but touched the back of the cabinet

make sure they're cut so that the grain goes across and there will be enough give in them

glue and screw the first to a batton running across the front of the cab then bend it over and glue and screw to the top of the baffle

you can then panel pin the next two sheets down with loads of pva inbetween especially from across the baffle and with plenty on the bit that over hangs to make sure of a good joint

if you look at this picture you'll see a length of wood being held by a G clamp this was pushing down on to the sheets ensuring enough pressure was there during the drying so that it's sealed well

to be honest that is the most important part that you have to make sure is completely glued up or it will vibrate

the final sheet is screwed through into the batton and baffle again the wood is placed there for pressure whilst drying

once it's all dry all you have to do is measure 120mm from the back and saw it off in a straight line

loophole wrote: what do you think of the structural strength of doing it that way davey? its tempting, but i'd be worried about glue in the inner layers setting correctly certain patches inside might never get the cure they need to get the glue's full strength

Its as solid as rock. Used lots of glue and screws and it set as if it was a 18mm thick piece of ply. I really reccomend doing it this way, it made them so easy to build.

matieo wrote: Firstly, thanks for an excellent resource! I would like to make a HD15. Unfortunatly I am inexperienced in carpentry so am trying to simplify the plan as much as possible. Would either of these modifications be sensible, how much would they damage the performance of the speaker? - Replace the curved section with 3 pieces cut with angled (mitred?) edges to simulate a curve - Have the back or base removable for driver access Of course, if all go's well; I will want to make more than one Matt

I.ve build a few double HD15 with the curved section replaced by 2 peices, and one of them is removeble for speaker access.          ;     The original HD15's i've build are powered by Beyma 15G400 speakers.  The double versions are powered by 18Sound 15W1402, and the a few with neodymium drivers from 18Sound.

Kind regards

Jack