Surface or flush mount Markaudio CHP-70

[AUtgr85]

New this forum and diy, so firstly please excuse my ignorance.

I'm planning on making a set of small bookshelf monitors with a built in t-amp as a wedding present for a couple of friends. I was considering using the BR design from the markaudio site, but I don't have access to a CNC or router circle jig to flush mount drivers as per the technical drawings. What I do have is a 4 inch hole saw to make the driver cutouts, so I could easily mount directly on the baffle surface. I am wondering whether surface mounting the drivers will seriously impact sound quality. The couple receiving this gift are by no means audiophiles, but I would still like these speakers to sound as good as possible.

Any input would be appreciated!

T

[planet10]

With the thick circular bezel on the Mark Audio drivers it is advised to have them flush mount. There are a number of ways to accomplish this.

1/ a rebate in the baffle (requires a router, a jig is easy)
2/ an additional piece of material fitted on top of the same thickness as the bezel. If a solid panel then you'll either need a jig saw or another hole saw of appropriate diameter. But it could also be a dense felt (you can get away with sissors) or something like cork (where a utility knife would likely be sufficient).

Of even greater importance thou is to relieve the back of the driver cutout (a good rasp is sufficient here)

dave

[chrisb]

Even though I'm spoiled by usually having access to a CNC, a dedicated circle cutting jig for router is very easy to build, and will give you great results, Due to the wide flange margin on the CHP70 (over 10mm) it does take some careful measures of depth to route rebate and through hole from the same center pivot of a circle jig. A 1/2" diameter plunge bit will allow this in one pass for the rebate.

Or after cutting the through hole, you could make a separate template for the larger hole, place the driver, align & clamp the pattern, then route the rebate with a top bearing pattern following/mortising bit.

But if you don't have a router at all, then Dave's suggestion of adding second layer (1/4" thick should work just fine) with larger cutout for the flange would also work.


The extra work of rebating any of the MA drivers is definitely worth it sonically, as well as aesthetically - and absolutely chamfer or round-over the rear side of driver mounting hole on any driver of this size.