Speaker mounting question- Pensil 10p

[crcook]

New speaker builder question- I am building a pair of Pensil 10Ps, and have made all the straight cuts on the BB ply. Test clamped, and everything looks good. Next step is to cut holes for speakers.

Do the speaker need to be flush with the speaker front? Most of the pics have shown the speaker flush with the surface, but I would have a tough time doing a perfect recessed opening with the tools I have. If the bezel of the speaker could sit on the wood, as opposed to being fully recessed, would that significantly affect the sound?

 

[sreten]

Hi, generally no, and not much at all, rgds, sreten.

 

[vinylkid58]

Do the speaker need to be flush with the speaker front?

I don't recall ever seeing a speaker using MA drivers where the driver wasn't flush mounted. The front baffle will need to be thick enough to secure the driver after the rebate, which means you'll probably want at least 22-25mm of material where the driver mounts, because you'll loose approx. 10mm for the bezel. Don't forget to chamfer 45 degrees on the backside of the cutout, but leave full material near where the screws go thru.

What is your front baffle thickness, 18mm?

jeff

 

[crcook]

Using 3/4 inch (~19mm) baltic birth ply. Plan on cutting hole for speaker to fit into front baffle, but the outer rim will protrude, not be flush with baffle surface. That also gives me more wood for longer screws and a secure mount. I see a lot of pictures of full range system in this site, some have flush mounted drivers, some don't. Not too hard to do with a 4" driver, there are hole saws that mount on drills. That is what I did when I made some speakers 10 years ago. Going with the bigger MarkAudio drivers means getting a quality router circular jig and good quality router bits to cut out a recess for the speaker rim. It also means less material behind to support the screws.

While I could buy the extra tools, I am OK with the driver not being flush, as long as it is not a major concern with the sound.

 

[vinylkid58]

Going with the bigger MarkAudio drivers means getting a quality router circular jig and good quality router bits to cut out a recess for the speaker rim. It also means less material behind to support the screws.

There is another way, without the need for a router, although you still need to cut a nice round hole. Just add a thinner piece of material to the front of the baffle, roughly the same thickness as the driver bezel. Voila, the driver is now flush mounted.

I believe there is a sonic advantage to flush mounting MA drivers, so it's worth the effort.

jeff

 

[planet10]

With the thick bezels the Mark Audios really want to be flush mounted. An approach different from the rebate, is to build up the baffle after the fact to achieve flush mount. Something like cork makes it a fairly easy task.

dave

 

[GdK]

I did what Jeff suggested. For the front i used 2 pieces of 12mm bb, so the driver is nicely flush mounted. I used 18mm bb for the other pieces.

Btw: completed the build, i love the sound! Thanks for the design and awesome drivers.

 

[Scottmoose]

Wise. In general, when it comes to wideband units more than about 3in, I'd say sreten's about on the money. However, the Alpairs have unusually broad dispersion for units of their size -surface mounting them = not a good move.

 

[larryldspkr]

You could incorporate flush mounting with your grills.

Larry

 

[Andrewbee]

Hello Chaps,
The doc says rest but its utterly boring. So I'm up and about early this morning.

An interesting thread. Ideally, its is better to flush mount the drivers. I appreciate that for newer members with less wood-working experience and for regular experimenters, surface mounting is a fast easy option. Provided you are prepared to accept the likely acoustic shortfalls already mentioned and don't blame the driver, then its possible to still get a musical outcome. All the same, please try to flush mount when ever possible into baffles between 18mm to 25mm thick (depending on driver size). Remember to flare or angle the baffle hole side wall to help avoid reflections on to the back of the driver's cone.

For those members with limited wood-working equipment, a possible solution is to laminate the front baffle with 2 or 3 thicknesses of wood/ply. 2 sizes of hole will make up a recess and get you on or close to flush mounting. Possibly your local wood merchant/yard could cut the holes for you.

Cheers
Mark.

 

[chuyler1]

If you're going to be building speaker cabinets having a perfect circle jig and a router are a must (even if it's a cheap one like the the one in the link). Even the most steady hand will screw up cutting a circle to mount a speaker. You'll spend hours sanding it to get the basket to slide in or you'll go too far and end up with gaps. It's an upfront investment in your sanity and you'll find it comes in handy for lots of other tasks like creating the chamfered inner lip to your speaker cutouts, beveling edges of the cabinets, or trimming a little overhang after you glue boards together.