Particle Board(I know, I know...)

[Heli-Tim]

While I'm sure that this is frowned upon in the DIY community, I know that a lot of manufacturers (most?) use particle board for speaker cabinets/bracing(I don't mean MDF). I personally like working with real wood products significantly better, but am seriously considering particle board for its light weight. I have 3 herniated discs, and every pound I can save counts!

Any thoughts on this?

Edit: I think it might also be called or is similar to melamine.

Cheers,
Tim

[Alaric]

I think MDF is chosen for it's density and low resonance qualities, along with minimal temperature related changes. I have no idea how particle board compares, but I would at least investigate those attributes. Considering the difference in weight vs. area, I would already suspect the resonance issue would raise its head. And from the some of the wild warping I've seen from particle board furniture I suspect it doesn't compare well on that score, either.

I have no idea if there are different grades of particle board, or how much its shortcomings can be attenuated with sealing and bracing. Particle board doesn't like humidity. Under damp enough circumstances, a speaker cabinet could end up looking like an old outhouse.

[Heli-Tim]

I was surprised to see that B & W used it in their cabinets.

I had planned on using Baltic Birch, or similar. I've been hesitant to start building my speakers partially due to the weight (but mostly home renovations, and having a kid).

You raise some good concerns.

[PMazz]

[TMM]

If you want to save weight, the key is bracing. You want the bracing to divide large panels into smaller ones so that the panel resonances occur high enough in frequency that they are not excited by the woofers. A series of 'window frame' shelves are generally quite effective and do not cost much weight. If you can divide all panels into sections no larger than 20x20cm you will be doing well. As a result 16mm sides and 12mm bracing is fine imho.


There is not much difference between the better grades of MDF and particle board as shown above. Instead of using a low grade of particle board, you could use a thinner sheet of MDF instead and achieve similar weight/strength ratio. Then make up for the reduction in strength by using a clever bracing scheme. MDF cutting a whole lot nicer than low grade particle board would be enough motivation to stick with MDF for me.

[Heli-Tim]

Thanks for the tips. I was/am leaning towards Baltic Birch . I just like to explore all my options first. In reality, my wife will have to move these around for me, as I cannot lift more then 20lbs (and has to be tight to my center of gravity) . It's always frustrating when something out of your control limits your project choices :s

[BobEllis]

I picked up a hand truck when I built my Ardents. I use it all the time now.

To re-hone my woodworking “skills”, I built a set of MDF Ardent cabinets before the BB/bamboo final versions. The MDF weighed 1/3 less than the BB/bamboo versions. BB is so much nicer to work with, I’ll never use MDF again.

[Heli-Tim]

Bob, I love your Ardents!

14 years ago when I was only 19, I took a bad kick to the spine in a martial arts tournament. The result is that I can't lift very much, and I have some nerve problems in my right hand that make it hard to use tools that vibrate. I definetly have challenges ahead of me while building these speakers .

I have some woodworking skills, I just need to make the right tools to do the job.

A hand truck will be a "must" for me. It is absolutely amazing sometimes,what we as humans can overcome to accomplish our goals.

[Bear]

I'll second the opinion of the superiority of BB to MDF. Aside from the general messiness of working with MDF, the screw holding of MDF is terrible, especially if you need to withdraw the screw for any reason and screw it back in. This is why so many people use hurricane nuts or T-nuts to mount drivers. There are a lot more disadvantages for MDF, but there's little need for me to rehash that here.

Bracing matters a lot for big cabinets, and increasing the the bracing density using lighter sheet goods can go a LONG way. In fact, if you think of something like a torsion box, you get an idea about how lighter weight and improved mechanical strength can go hand-in-hand. I often refer to the "sagulator" (https://www.woodbin.com/calcs/sagulator/) as a reminder of how much strength one can gain with just a bit of additional material applied in the right locations.

A big caveat, though: bracing matters most when doing larger cabinet sizes. If you face significant limitations, please consider smaller or multi-box designs, rather than larger monolithic ones. You don't need a 100 pound speaker that lives in the middle of your shop, no matter how elegant! :-)

On this forum, JonMarsh's Modula series, especially the Modula MT-XE and Xtreme, can give you an idea of what a multi-box design can look like and perform like. His method of using pre-built (or flat pack) cabinets not only helps reduce time to build, but also reduces the requirements for tools/tool use. Outside of this forum, a designer like Troels Gravesen is both well-respected and also includes many compound box designs on his website, though these tend to require a significant number of machining/construction steps (e.g., http://www.troelsgravesen.dk/Illuminator-5.htm).

Start with considering your goals. If you are a two-channel purist who wants a "20-20" speaker, then a larger, monolithic design may be your best bet. If you want good multi-channel playback (music and HT), and you are not averse to subwoofers, then life becomes a bit easier. Many people get fixated on low-end extension for smaller drivers who are then paired with subs. A good sub or woofer that can cover the 20 - 200Hz range and an active crossover to a 5" mid + Tweeter should give you great sound with a minimal construction load. Subwoofers like the SEAS L26ROY or Wavecor SW223 in a flatpack box with a DSP/Amp combo should easily cover a 200Hz or 300Hz crossover point. Something like the Dayton RSS315HF can probably handle 200Hz, though 300Hz is probably too high. At a 200 - 300Hz crossover point, you may be Xmax limited in the woofer for your ultimate SPL, but porting the midwoofer won't be necessary (saving construction effort and expense).

A very concrete example: I use Mark K's ER18DXT design for my surrounds, and they'd be quite good as main speakers when crossed to a sub. They're designed for the 0.5cf Parts Express cabinet (which is still available). And while they are decently heavy when built, a design like the Ardent will dwarf them. Because the cabinets are pre-finished, you can also assemble them in-situ, rather than having to move them around a shop, then transporting to their final location. Also, all that you need is a few standard hand tools (e.g., screw drivers), a soldering gun, a drill driver, a router and a circle jig (e.g., Jasper Jig). Replacement baffles are (relatively) cheap and available in case something goes wrong cutting the driver holes. I actually cheated entirely when building mine since Madisound still offered pre-built cabinets back then, and I used Madisounds CNC machined baffles, as well, which fit the ER18 woofer and DXT tweeter perfectly (this should also give you an idea of how they have held up over time...).

http://er18dxt-backer.blogspot.com/2013/12/overview_8.html

https://www.parts-express.com/dayton-audio-twc-050ch-050-cu-ft-2-way-curved-speaker-cabinet-cherry--302-723

Hope this helps!

[Steve Manning]

Bob's idea about a hand truck is a great idea regardless of the type of wood you use. They make a big difference in moving stuff around. With something like this, https://www.amazon.com/VEVOR-Climbin...FBY340RGP3PMRS you can do all kinds of crazy stuff.