I've never had a crack in a finished speaker before, so I've never bothered. I don't really see how biscuits would help though. We are talking about very small amounts of movements, so I don't see how they would help, but maybe I'm wrong.
I've heard of the issues that Markus had happen, but I've never experienced it myself. I don't know what causes it, so I can't speak to how to prevent it. I used gorilla glue in my last enclosure, which is designed to work with wood, and many pro's do use it in furniture assembly. There were no cracks on that enclosure. The current ones are too new to know I suppose. I would be surprised if they cracked though, I spent a lot of time getting those joints right.
Markus, didn't you use woodglue and water as your sealer? If not, what did you use to seal the wood before finishing? Woodglue and water does work well on the open wood joints, but I don't find it best on all of the cabinet. I think something with shellac is great for the overall cabinet, such as the BIN that I used this time, or even normal sanding sealer as I have used in the past.
I've heard of the issues that Markus had happen, but I've never experienced it myself. I don't know what causes it, so I can't speak to how to prevent it. I used gorilla glue in my last enclosure, which is designed to work with wood, and many pro's do use it in furniture assembly. There were no cracks on that enclosure. The current ones are too new to know I suppose. I would be surprised if they cracked though, I spent a lot of time getting those joints right.
Markus, didn't you use woodglue and water as your sealer? If not, what did you use to seal the wood before finishing? Woodglue and water does work well on the open wood joints, but I don't find it best on all of the cabinet. I think something with shellac is great for the overall cabinet, such as the BIN that I used this time, or even normal sanding sealer as I have used in the past.
thing's can often look less deep if they are made wider than they are deep, and having a rear that is less wide than the wrong. What about offering a rear surround wall mount version with a different enclosure design that follows this sort of design?
markus76 said:
Markus - no I did miss that picture. Clearly you rushed the assembly. I've never had this seveer a problem. As I said I don't ever see problems at all anymore, but that has taken some time to learn. One thing that I do not do is rush things. I let parts and assemblies sit for days before moving to the next step. If I remember correctly, you were done in about a week.
pjpoes said:
Yes, I have noticed that the CLD panels can shift, so now I put in a nail to prevent that. I would have checked the fit of the back panel before I mounted the crossover parts. Its trivial to correct the problem if there aren't parts on the boards - just pass it through a table saw with the blade set at the correct depth (1/2") and you can easily trim off 1/8". Of course with all the parts mounted this is not possible. MDF is so soft that it can also be cut with a knife, so thats what I would do. A box cutter with new sharp blades will trim off 1/8" in a few minutes - just do a little at a time. That way you don't have to remove anything. You can easily trim the baluns that way too, although the CLD boards on the back panel would be easier since they are only 1/2". Sounds to me like your baluns might have gotten a bit too wide. They should be 1" wide. Is that correct?
How long did the enclosure set before you started to paint? Its not how fast you paint, its more how long the enclosure sets after assembly so that it has time to settle.
pjpoes said:
Making a tapered enclosure dramatically complicates the panels cutting and the assembly and then its only appearance, the enclosures still need to be deep enough to allow for the waveguide.
There is no end of products that can be offered, but they take time. After the Harper I'm going to do subs.
I can tell you that I probably won't assemble the next set myself. It's not worth the savings in my opinion. We shall see how I feel when that time comes, but at the moment, I won't be assembling myself.
With the Harpers, the enclosure will probably be sent out assembled since they are small enough that this makes sense. That takes away a lot of problems. Then the customer can get them painted or not. The plan now is also to have square edges on the sides so that they can be veneered. But the front will virtually always need to be painted.
I can see that selling kits is not really a very good idea since there are too many things that can go wrong. I have some kind of problem every time I build one, but then I just correct it. But someone without my experience is likely to have lots and lots of problems. Making a "fool" proof kit would make it almost as expensive as the assmebled kits in which case what's the point? I keep fixing small things, but the big problems, mostly finish, simply have to rely on the capabilities of the end user. There is no way that I can "teach" paint and the equipment required for a really good finish is prohibitively expensive. All in all you save a little money with a kit, but you are in for big headaches.
I can see that selling kits is not really a very good idea since there are too many things that can go wrong. I have some kind of problem every time I build one, but then I just correct it. But someone without my experience is likely to have lots and lots of problems. Making a "fool" proof kit would make it almost as expensive as the assmebled kits in which case what's the point? I keep fixing small things, but the big problems, mostly finish, simply have to rely on the capabilities of the end user. There is no way that I can "teach" paint and the equipment required for a really good finish is prohibitively expensive. All in all you save a little money with a kit, but you are in for big headaches.
Dr. Geddes,
It's probably better if you start the Harper thread.
That way you can post your graphs and basic info (drivers used, XO freq, purchase options/prices), forestalling a lot of questions that would be posted otherwise.
It's probably better if you start the Harper thread.
That way you can post your graphs and basic info (drivers used, XO freq, purchase options/prices), forestalling a lot of questions that would be posted otherwise.
gedlee said:
Well, 18 days because I had to wait for the manufacturer to send me new top boards 😉 It's the not very dense MDF swelling from that water based sealer and paint.
There sure are a lot of issues with these cabinet. This is not towards Gedlee, but to anyone using MDF. I sill think birch plywood would have less issues. I did not know MDF was so sensitive to moisture or humidity. Someone mentioned that the plywood can be too expensive, and MDF is cheaper. For a speaker project that costs $2400 for a pair, the cost difference between MDF or plywood is so little, it's silly.
Also, all these different glues. I have read about so many in this thread, I can't keep them straight.
I don't have all the experience building speakers like most of you do. So I come here to read and learn. I have only built one pair of speakers ever. It was about 4 years ago. I still use them today. I used a combination of MDF and birch plywood. The glue was Elmer's carpenter wood glue. The cabinets are solid as a rock.
I did want to add that I think Earl is doing a good job with his kits. I may buy something from him in the near future. I just wish the 12TBX100 was not so expensive. Especially is a design that is not trying to get the most bass output.
Also, all these different glues. I have read about so many in this thread, I can't keep them straight.
I don't have all the experience building speakers like most of you do. So I come here to read and learn. I have only built one pair of speakers ever. It was about 4 years ago. I still use them today. I used a combination of MDF and birch plywood. The glue was Elmer's carpenter wood glue. The cabinets are solid as a rock.
I did want to add that I think Earl is doing a good job with his kits. I may buy something from him in the near future. I just wish the 12TBX100 was not so expensive. Especially is a design that is not trying to get the most bass output.
tomcat9 said:
I don't consider this "issues with these cabinets". To me it's normal DIY talk. Obviously Earl and others are capable of painting MDF enclosures that don't have any issues at all.
Plywood is more dimensionally stable I believe, but any wood product swells and contracts. In fact, I believe I have read that solid wood is the worst in that regard. Anyway, I have seen the same problems with birch plywood, and quality consistency issue with birch ply makes it difficult to use. Once you have a good supplier it's less of an issue, but cost is still pretty high.
I don't think any of my problems have been because its mdf, they were just little minor issues that all added up to create small fit issues. I've not had any finish problems as a result of MDF, mine were the result of sub zero weather and an inability to keep my garage above 50 degrees. Really I should be spraying in 70+ degree weather with minimal humidity. I also didn't fully listen to Dr. Geddes recommendation on paint and made the mistake of thinking that any water based acrylic enamel was the same, and bought what turned out to be nothing more than a slightly tweaked latex house paint called acrylic enamel. The finish looks great, but isn't durable enough, and will be redone when weather permits.
Dr. Geddes hasn't responded to let me know for sure that this was the issue, but apparently those rear baluns were supposed to be 1" and turned out to be more like 1 1/8th of an inch, so it looks like my 1/4" problem was due to a slight issue with the guy who cut the parts for Dr. Geddes. Those rear braces were slightly off in every dimension actually, not that it caused big issues, but the long ones were too long, and the shorter ones were too short. I had to use prodigious amounts of fill to seal those gaps, and I had to cut down the long ones by about a 1/4" each. I can't fault Dr. Geddes as he didn't cut these. They were cut by a guy using a CNC router, and I can't expect that he would have measured every single piece that came in to ensure that every one was correct. I would have assumed they were correct. Again, it wasn't that big a deal to fix either, I just needed to think about the problem for a moment. I have far more problems when I design and build my own speakers and enclosures than I have had with this kit. I can't compare this experience to other kits I have built really as they used either pre-assembled boxes or were tiny bookshelf speakers, which made fixes much easier.
I don't think any of my problems have been because its mdf, they were just little minor issues that all added up to create small fit issues. I've not had any finish problems as a result of MDF, mine were the result of sub zero weather and an inability to keep my garage above 50 degrees. Really I should be spraying in 70+ degree weather with minimal humidity. I also didn't fully listen to Dr. Geddes recommendation on paint and made the mistake of thinking that any water based acrylic enamel was the same, and bought what turned out to be nothing more than a slightly tweaked latex house paint called acrylic enamel. The finish looks great, but isn't durable enough, and will be redone when weather permits.
Dr. Geddes hasn't responded to let me know for sure that this was the issue, but apparently those rear baluns were supposed to be 1" and turned out to be more like 1 1/8th of an inch, so it looks like my 1/4" problem was due to a slight issue with the guy who cut the parts for Dr. Geddes. Those rear braces were slightly off in every dimension actually, not that it caused big issues, but the long ones were too long, and the shorter ones were too short. I had to use prodigious amounts of fill to seal those gaps, and I had to cut down the long ones by about a 1/4" each. I can't fault Dr. Geddes as he didn't cut these. They were cut by a guy using a CNC router, and I can't expect that he would have measured every single piece that came in to ensure that every one was correct. I would have assumed they were correct. Again, it wasn't that big a deal to fix either, I just needed to think about the problem for a moment. I have far more problems when I design and build my own speakers and enclosures than I have had with this kit. I can't compare this experience to other kits I have built really as they used either pre-assembled boxes or were tiny bookshelf speakers, which made fixes much easier.
Matt
Actually I do cut those pieces - my bad! But the long ones would be off by the 1/4" you noted if the width of the other two was 1 1/8". That's the issue, and I'm not sure how that happened. In a rush probably and didn't check the saw setup. I actually have to put on magnifying eye glasses when I need to make precise cuts because I can't see the fine gradations without them. Sometimes I guess.
As to MDF, paint, plywood, etc. you have to remember that they would all have problems if sprayed outside when the weather was sub zero. Matt should not have done that, I warned him, and he is paying the price now. I have no problems with MDF, and plywood, when routed like these cabinets are, would have just as much trouble with grain on these edges because of its alternating pattern and it would have to be premium plywood to not have any voids. There is a very good reason why you don't see round overs on a lot of speaker cabinets - they are hard to finish. The finish would be trivial with standard square edges - but then the sound would also degrade.
Actually I do cut those pieces - my bad! But the long ones would be off by the 1/4" you noted if the width of the other two was 1 1/8". That's the issue, and I'm not sure how that happened. In a rush probably and didn't check the saw setup. I actually have to put on magnifying eye glasses when I need to make precise cuts because I can't see the fine gradations without them. Sometimes I guess.
As to MDF, paint, plywood, etc. you have to remember that they would all have problems if sprayed outside when the weather was sub zero. Matt should not have done that, I warned him, and he is paying the price now. I have no problems with MDF, and plywood, when routed like these cabinets are, would have just as much trouble with grain on these edges because of its alternating pattern and it would have to be premium plywood to not have any voids. There is a very good reason why you don't see round overs on a lot of speaker cabinets - they are hard to finish. The finish would be trivial with standard square edges - but then the sound would also degrade.
markus76 said:
Markus
My point also. MDF requires some special care, but in the end can have just as good a finish as anything else. My last Nathans had a premium high gloss black piano finish on MDF and it was fine. I had some problems with the paint, but none with the MDF.