Sorry if this is a dumb question, but every speaker box build video I watch and all the directions I read all show gluing and clamping MDF. Is there an acoustic, or other reason I am not aware of for not using any screws in the box construction? Or is this just because it simply makes the finish work easier? I'd like to countersink flat head screws and putty/sand. Is that a bad idea?
Thank You,
-RP
Thank You,
-RP
Robert - in my own experience, there's no particular reason to not use screws, but a couple of cautions. Even with properly countersunk pilot holes, keep the screws at least a couple of inches away from corners - MDF has much softer core than the face and splits quite easily. Today's wood glues are strong enough that unless subject to a lot of abuse - or the need to hang a cabinet on the wall - that with smooth joint surfaces, you can get a pretty sturdy cabinet. I happen to use Baltic Birch plywood almost exclusively, and have built literally hundreds of speaker boxes without any fasteners at all.
What type of finishing did you have in mind?
Please don't say High Gloss Paint - cause if you have to ask the earlier question, I'd imagine you aren't aware of the huge amount of time and materials required for that. 🙄
I avoid painting speaker boxes as much as possible, and when I do, it'll be stone coat textured products on back panels, or on shadow line reveals or visible slot ports.
As Cal noted above the subject of assembly techniques - and for that matter painting - has been discussed in various forums here ad nauseam.
What type of finishing did you have in mind?
Please don't say High Gloss Paint - cause if you have to ask the earlier question, I'd imagine you aren't aware of the huge amount of time and materials required for that. 🙄
I avoid painting speaker boxes as much as possible, and when I do, it'll be stone coat textured products on back panels, or on shadow line reveals or visible slot ports.
As Cal noted above the subject of assembly techniques - and for that matter painting - has been discussed in various forums here ad nauseam.
If all goes well and it sounds how I hope; I plan to add a wood veneer. I am adding a 1/4" real hardwood baffle during the build, so I don't have to veneer the front and to counter-sink the drivers flush.
The main reason I ask about the screws, I just don't have near enough clamps, but I have hundreds of screws. As long as it isn't an acoustic reason, I would just as well not have to go buy a bunch of clamps for one project and have no place to store them when i'm finished. I'm just doing a statement ii build with a different tweeter, so not re-creating too much wheel.
The main reason I ask about the screws, I just don't have near enough clamps, but I have hundreds of screws. As long as it isn't an acoustic reason, I would just as well not have to go buy a bunch of clamps for one project and have no place to store them when i'm finished. I'm just doing a statement ii build with a different tweeter, so not re-creating too much wheel.
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Just don’t use MDF, it is not a very good speaker box material.
On another note, i have never been able to break any of Chris’s builds, and if they were to be hung from the roof, special design considerations would be used in the design.
dave
On another note, i have never been able to break any of Chris’s builds, and if they were to be hung from the roof, special design considerations would be used in the design.
dave
Dave, this is my first speaker build ever; so with the plans calling for 3/4" MDF and it being far cheaper if I screw up, I think this one will have to be MDF. I can always take my time and build some better cabinets if the sound turns out to be a long-term keeper. Total MDF cost is only $115, I'll be thrilled to scrap that $115 if they turn out to be worthy of a good hardwood.
That’s like 3 sheets of MDF up here… how big are the speakers?
And if you build them of MDF and don’t like them how do you know if it is the speaker design or the MDF?
dave
And if you build them of MDF and don’t like them how do you know if it is the speaker design or the MDF?
dave
Good, this has turned into a far more interesting pointless discussion about something that has never been discussed at length here before
If you are veneering the boxes don't use butt joints. I execute 45 degree miters and lock miters for Baltic Birch, regular miters for PB and MDF. I don't used MDF very often because of the dust.
Thanks for the tip on the Miter'ing. Honestly fellas, I'm not too concerned at all about appearance (right now). These are going in my listening room and if I get any WAF grief I will show her the door; she has the whole rest of the house. The sound is my first and almost only concern.
Dave, I am building statement ii's with a different tweeter, never been a fan of ribbons personally. Speaker Design Works So yeah, looks like 3 sheets of 3/4" MDf and 2 sheets of 1/4" birch for the baffle.
Dave, I am building statement ii's with a different tweeter, never been a fan of ribbons personally. Speaker Design Works So yeah, looks like 3 sheets of 3/4" MDf and 2 sheets of 1/4" birch for the baffle.
Since this first build will be MDF, no one has any objections to screws in place of clamps, correct? Stay away from edges, corners, pilot drill first, be careful, otherwise okay? No acoustics objections to screws? I think that's what I'm hearing.
Last question, what's the recommendation in spacing for the screws, keeping in mind I won't be using clamps while the glue dries. 4"? 6" 8"?
Last question, what's the recommendation in spacing for the screws, keeping in mind I won't be using clamps while the glue dries. 4"? 6" 8"?
I used neither screws nor clamps, I just weighted the joints, had to be patient, couldn't do it all in one go. Advantages are, easier to get precise alignment and no chance of forcing out too much glue
8" spacing should be sufficient, unless you notice bulging between screws. Best if you clamp the wood to hold alignment, then drill pilot holes and re-clamp to hold alignment again, while you install the screws.
Dave,have you tried concrete? I've wanted to try it for decades. But then I haven't really noticed(subjectively) a difference between MDF vs Baltic Birch.
These guys used Stone and then added an angled board internally(measurement supported) to damp a resonance.
http://www.kirchner-elektronik.de/upload/15522377-Speaker-Development.pdf
Which tweeter? Have you got a plan for modifiying the XO? We have had the mids thru here (they can be used as a small FR), they are nice.
With the significnt budget for drivers and all th elabour involved are you sure using MDF instead of ply is really a significant cost savings relative to the entire budget. Also keep in mind that 15mm quality ply (we use Murphy Ply), will give a stouter build than ¾” MDF. And your back will really thank you.
With a box this big i would have expected more bracing.
dave
Dave, if I wasn't a complete rookie at the woodworking part I would have done something besides MDF, but I'm about a mile from Lowe's to grab another sheet when I inevitably screw up. I can pretty much repair anything electronic, but woodworking is very new to me. That's also why I went with this Statement ii build, everything is a square or rectangle, keeping this first one nice and simple.
As for the tweeter, I went with the SATORI TW29RN, I've heard nothing but good about it and it's a lot more "my type" of tweeter. I used WinPCD for the crossover design and the original crossover looked quite good on the TW29RN-B. I made some minor tweaks and ordered the components for the default Xover and for the one with my changes, I'll tinker and see what sounds best. I also have the option of going active if need be, I have a few minidsp units including a 2x8 I'm not currently using. I've never done a full active Xover, but that's another reason to avoid the ribbon, IMO.
As for the tweeter, I went with the SATORI TW29RN, I've heard nothing but good about it and it's a lot more "my type" of tweeter. I used WinPCD for the crossover design and the original crossover looked quite good on the TW29RN-B. I made some minor tweaks and ordered the components for the default Xover and for the one with my changes, I'll tinker and see what sounds best. I also have the option of going active if need be, I have a few minidsp units including a 2x8 I'm not currently using. I've never done a full active Xover, but that's another reason to avoid the ribbon, IMO.
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You should glue MDF and use wood dowels.
And you should use two layers of MDF glued together.
Or birch multiplex.
And you should use two layers of MDF glued together.
Or birch multiplex.
The front is multilayer glued, 1-1/4" total thickness, the rest is all 3/4". You think the whole box needs to be multilayered? I'll need a crane to move them 🙁 I think that 3/4" MDF comes in somewhere around 90lbs a sheet.
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