Re: Re: Re: Re: Carcass construction
Dave, this could be another thread and I don’t want to be argumentative but why do so many other sources recommend MDF then? I was under the impression that it is an inert (no/little expansion) and reasonably resonance free material. I thought it was a “close call” between MDF/plywood!
As I haven’t built a lot of speakers I’d like to hear what you and others think on the matter.
planet10 said:
Dave, this could be another thread and I don’t want to be argumentative but why do so many other sources recommend MDF then? I was under the impression that it is an inert (no/little expansion) and reasonably resonance free material. I thought it was a “close call” between MDF/plywood!
As I haven’t built a lot of speakers I’d like to hear what you and others think on the matter.
Re: Re: Re: Re: Re: Carcass construction
1st off i don't know of anyone who recommends MDF for the Fostex Horns.
That so many recommend MDF is -- for the want of a better term -- "don't know any better" syndrome.
That MDF is good is pretty much just conventional wisdom. The guy that recommended it you is using it -- and hasn't tried anything else -- because some "expert*" told him that... and he holds that because some expert told him that. This kind of thing happens all the time (ie that Microsoft word ddn't get to be the most popular word processing program had nothing to do with it actually being a good word preocessor (which it is decidedly not)).
*expert being anyone with more experience than you
Now, you do need to stay away from "just plywood"... you need to use void free ply. This costs about twice what MDF costs.
Of course there are all the "good" reasons that manufacturers give you that MDF is better. Most of these are really marketing to justify its use because it is cheaper, easier to work, and easier to finish (ie they can build the box cheaper).
If you look at the best of the commercial speakers, you will note that large numbers of them don't use MDF (althou some use combinations of MDF & ply or even of particle board (which althou ugly to work with is probably preferable to straight MDF). And often the ones that are made of MDF are really not MDF but plywood made of MDF (translam for instance). HDF is also preferable to MDF -- i have built some pretty good boxes with well-braced 1/2" HDF.
ut for these horns, spend the money, go out and get some void free plywood.
dave
greenie512 said:
1st off i don't know of anyone who recommends MDF for the Fostex Horns.
That so many recommend MDF is -- for the want of a better term -- "don't know any better" syndrome.
That MDF is good is pretty much just conventional wisdom. The guy that recommended it you is using it -- and hasn't tried anything else -- because some "expert*" told him that... and he holds that because some expert told him that. This kind of thing happens all the time (ie that Microsoft word ddn't get to be the most popular word processing program had nothing to do with it actually being a good word preocessor (which it is decidedly not)).
*expert being anyone with more experience than you
Now, you do need to stay away from "just plywood"... you need to use void free ply. This costs about twice what MDF costs.
Of course there are all the "good" reasons that manufacturers give you that MDF is better. Most of these are really marketing to justify its use because it is cheaper, easier to work, and easier to finish (ie they can build the box cheaper).
If you look at the best of the commercial speakers, you will note that large numbers of them don't use MDF (althou some use combinations of MDF & ply or even of particle board (which althou ugly to work with is probably preferable to straight MDF). And often the ones that are made of MDF are really not MDF but plywood made of MDF (translam for instance). HDF is also preferable to MDF -- i have built some pretty good boxes with well-braced 1/2" HDF.
ut for these horns, spend the money, go out and get some void free plywood.
dave
Re: Re: Re: Re: Re: Carcass construction
i once built 2 sets of vented loudspeakers. they were identical in every respect except for the material.
1 set was good birch ply, 1 was set was veneered MDF. the birch ply ones were my prototype.
they sounded so much better it wasn't funny. i ended up trashing the MDF boxes, but the ply prototypes sold immediately...
greenie512 said:
i once built 2 sets of vented loudspeakers. they were identical in every respect except for the material.
1 set was good birch ply, 1 was set was veneered MDF. the birch ply ones were my prototype.
they sounded so much better it wasn't funny. i ended up trashing the MDF boxes, but the ply prototypes sold immediately...
Re: Re: Re: Re: Re: Re: Carcass construction
We did the same thing... MDF vrs BB Buschorns, and MDF vrs BB Doppenburg pipes. The MDF B-Horns burned nicely, the MDF BD-Pipes ended up at a clients because she fell in love with the maroon painted finish (we had to make a mathcing set for the reares (making that the last set of MDF BD-Pipes, but the CC was ply)
dave
noisenyc said:
We did the same thing... MDF vrs BB Buschorns, and MDF vrs BB Doppenburg pipes. The MDF B-Horns burned nicely, the MDF BD-Pipes ended up at a clients because she fell in love with the maroon painted finish (we had to make a mathcing set for the reares (making that the last set of MDF BD-Pipes, but the CC was ply)
dave
Re: Carcass construction
I did mine in three 4'x8' 3/4" ply sheets.
I like your idea of MDF. Someone should try this, although it isn't quite "purist." Be aware, though, that some have commented elsewhere that these type of enclosures should in fact use plywood for "some" flex. Otherwise the cabinet sounds too dead...and dull.
greenie512 said:
I did mine in three 4'x8' 3/4" ply sheets.
I like your idea of MDF. Someone should try this, although it isn't quite "purist." Be aware, though, that some have commented elsewhere that these type of enclosures should in fact use plywood for "some" flex. Otherwise the cabinet sounds too dead...and dull.
greenie512 said:
This is not my best example, but here's a DX4 in Lowther's
Medallion with and without an absorbent floor space between
the speaker and microphone. You can see the "comb effect"
from floor reflection pretty easily at 250 Hz spacing.
I say that this is not my best example because the placement
of the Medallion mouth and its tuning are such that the
inteference pattern occurs at about 250 Hz and is fairly minimal,
where usually it's around 150-200 Hz and the first dip is bigger.
Attachments
For tmmuch
Hi,
Sorry to use this thread to contact you but I don't know how else to do it.
I just ran across this thread and saw you are from AZ. If you haven't heard there is a DIY Speaker event in Tucson this coming Saturday. It's our 3rd annual event. Should be 25 - 30 people attending. See link for info.
I hope to be back from Vermont in time for it.
http://www.madisound.com/cgi-bin/discuss.cgi?read=332418
Russ
Hi,
Sorry to use this thread to contact you but I don't know how else to do it.
I just ran across this thread and saw you are from AZ. If you haven't heard there is a DIY Speaker event in Tucson this coming Saturday. It's our 3rd annual event. Should be 25 - 30 people attending. See link for info.
I hope to be back from Vermont in time for it.
http://www.madisound.com/cgi-bin/discuss.cgi?read=332418
Russ
Hey guys I bought these drivers also and just finished cutting up the plywood yesterday for the recommended box. I do have a question about the assemlby. Is it OK to use screws and glue to put the box together or should I use just use glue. I did not know if the screws would do anything to the sound. This is my first time using a full range driver and making a BLH box. So I just want to make sure I do it right. Thanks for your help.
John
John
Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Carcass construction
I too very much prefer livelier wood. Partially it's an aesthetic
physical choice (who wants particle board?), but there's also
a sonic quality that's pleasing.
At the same time, like a musical instrument, it takes quite a bit
of work to get it right, in contrast to MDF where you don't need
to think deeply about something that's dead.
It reminds me of the musicians who insist on using silver flutes
and the scientists who insist that concrete sounds just as good.
As much as I respect science, I go with the musicians.
I too very much prefer livelier wood. Partially it's an aesthetic
physical choice (who wants particle board?), but there's also
a sonic quality that's pleasing.
At the same time, like a musical instrument, it takes quite a bit
of work to get it right, in contrast to MDF where you don't need
to think deeply about something that's dead.
It reminds me of the musicians who insist on using silver flutes
and the scientists who insist that concrete sounds just as good.
As much as I respect science, I go with the musicians.
kazoo said:
Just glue requires a lot of clamps -- i like to use the belt & suspenders approach, and use screws to hold the panels togther till the glue dries... if you are not going to cover the outside with somesort of "veneer, then the discontinuity introduced by screws is something you may want to avoid.
dave
kazoo said:
Use both glue and screws...at least for the inner side walls and all of the internals that won't show. I used coarse drywall screws. Drill pilot holes. Countersink. Then fill with wood filler or whatever. Then you can just glue and clamp the hell out of the outer side (show) pieces. Maybe use a few finishing nails just to keep them from shifting during glue-up. Remove the nails after glue dries...or drive them home, use a nail set and fill.
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