XtrmAudioCncpts
10+ year member
CarAudio.com Veteran
wow good write up
XtrmAudioCncpts
LBX2G
10+ year member
R.I.P Camofluage
thnx for my cheat sheet......now to summarize ur info
ps........what about the different types of enclosures especially free-air //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif)
ps........what about the different types of enclosures especially free-air //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif)
- Thread Starter
- #20
what do u mean summarize...
what enclosure is free air...unless you mean infinite baffle? i'm reading a few Small articles on it right now and i'll have a synopsis later unless someone else is good enough to have the info right now (you know who you are) //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
what enclosure is free air...unless you mean infinite baffle? i'm reading a few Small articles on it right now and i'll have a synopsis later unless someone else is good enough to have the info right now (you know who you are) //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
JimJ
5,000+ posts
Tangled Up in Blue
Maybe he's talking about dipole setups...which actually would be a cool writeup to have, I remember seeing an article once about needed baffle sizes to reproduce different frequencies. Something like a 9 meter-high baffle is needed to produce sub-30Hz bass response free-air //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
LBX2G
10+ year member
R.I.P Camofluage
no i am going to make a cheat sheet like they sell for math in ur college book store.
- Thread Starter
- #26
Now that that is taken care of, onto some general cabinet construction tips, some superfluous, some important
When cutting the cabinet, it is a good idea to cut a few millimeters or 1/8" wide for good measure. This way, you can have over hang OR you will be dead on the correct measurement. The only reason for this is because when using circular saws, or table saws inparticular, most people dont account for the blade which is usally 1/8 or more by itself. By cutting them wide, you have a margin of error and can then just throw in a flush trim bit on the router and go to town for a fine finish.
The circle is the most important part of the enclosure, otherwise, where would the speaker go? //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
One good thing to do when making the cutout is to flush mount the cone. This makes it essentially a part of the baffle, thus keeping the drivers on the same plane as the baffle. This generally increases imaging and soundstage. Another tip is to make sure that the drivers are not equidstant from any baffle edge. While there is come disagreement on this, it doesn't hurt to try as long as the width is large enough to matter. Another good suggestion is to round-over the rear of the baffle. This essentially "unchokes" the air from the rear of the cone. For example, if you are using a small midrange in 1" plywood, the air from the rear of that cone has no space to go to. This is just a good tip if you want to do all that you can to improve the small things about your speaker.
Bracing is VERY important in both subwoofers and loudspeakers. While in subwoofers bracing is used for the reduction of flexing, in both subwoofers and loudspeakers effective bracing is IDEAL to cut down on cabinet resonance. Bracing effectively makes the cabinet ONE piece of wood rather than six. By increasing the rigidity of the structure, you are essentially strengthing it and allowing less unwanted noise in the enclosure. Think about it like this. You are a scrawny person holding a heavy barbell. Your arms quiver and shake from the weight. When someone helps you, or BRACES your arms, the quivering stops. While this is an elementary way of thinking, it is still quite relative.
There are three types of bracing, and one is more effective than the other two. They are listed in order of effectiveness, highest to lowest. The three main types are shelf braces, span braces (many names for these) and corner braces. The shelf braces couple all four sides. Imagine putting a shelf inside of a sub box. It is connected to the front baffle, rear baffle and the sides. These are now coupled to create a single piece. When a brace is put in the vertical direction as well, you are gold. These braces have holes cut into them so as not to impede airflow within the cabinet, but not so much as the integral strength of the brace is jeopardized. The problem with shelf braces is that they take up precious Vb. If you don't have a lot of room to spare (most trunks are on space constraints //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ) read on. The next brace, the span brace, couples two sides together. An example is a 1.5 x .75 inch piece of wood running the distance from the front to the back. This only couples two sides which is better than nothing. Very commonly used in enclosures that are tight on space as they are more effective than the last brace, the corner brace. This is just a square piece of wood placed in the corner between two cabinet sides. These are not ideal as the probability that the brace is LITERALLY on the sides is nil (unless screwed in, when the glue dries it sometimes takes it away from the corresponding wood) and thus possible jeopardizing the effective bracing qualities of the brace. However, these take up very little room as well and are common in small bookshelf speakers where a shelf is obviously impractical and a span brace may impede either a port or the driver itself.
Wood itself is probably the second most important part of a speaker (you don't HAVE to use wood, as apparently the closest to natural speaker was an aluminum honey comb tower from the 1970s, according to various authors) next to the driver. Wood materials are VERY important when considering what you want the enclosure to sound like. Believe it or not, wood makes a sound when acted upon. For most enclosures, the relative stiffness of MDF as well as it's damping quality makes it very popular. However, to get truly the best sound for your money, a good plywood has always shown to be superior. These woods are rather expensive though. By plywood, I don't mean the chipboard used for underlayments, I mean the plywood that is multiple layers thick and resembles flooring. Baltic birch is a personal favorite of mine, as well as oak. The damping characteristics of the plywood are better and have a tendency to resonate LESS than MDF (as said by Small in an article from the 70's, just so u don't think i'm makin that up //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ). However, for most builders, MDF is ideal because it is relatively cheap, sounds good, is better than particleboard and can be easily found and cut.
When cutting the cabinet, it is a good idea to cut a few millimeters or 1/8" wide for good measure. This way, you can have over hang OR you will be dead on the correct measurement. The only reason for this is because when using circular saws, or table saws inparticular, most people dont account for the blade which is usally 1/8 or more by itself. By cutting them wide, you have a margin of error and can then just throw in a flush trim bit on the router and go to town for a fine finish.
The circle is the most important part of the enclosure, otherwise, where would the speaker go? //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
One good thing to do when making the cutout is to flush mount the cone. This makes it essentially a part of the baffle, thus keeping the drivers on the same plane as the baffle. This generally increases imaging and soundstage. Another tip is to make sure that the drivers are not equidstant from any baffle edge. While there is come disagreement on this, it doesn't hurt to try as long as the width is large enough to matter. Another good suggestion is to round-over the rear of the baffle. This essentially "unchokes" the air from the rear of the cone. For example, if you are using a small midrange in 1" plywood, the air from the rear of that cone has no space to go to. This is just a good tip if you want to do all that you can to improve the small things about your speaker.
Bracing is VERY important in both subwoofers and loudspeakers. While in subwoofers bracing is used for the reduction of flexing, in both subwoofers and loudspeakers effective bracing is IDEAL to cut down on cabinet resonance. Bracing effectively makes the cabinet ONE piece of wood rather than six. By increasing the rigidity of the structure, you are essentially strengthing it and allowing less unwanted noise in the enclosure. Think about it like this. You are a scrawny person holding a heavy barbell. Your arms quiver and shake from the weight. When someone helps you, or BRACES your arms, the quivering stops. While this is an elementary way of thinking, it is still quite relative.
There are three types of bracing, and one is more effective than the other two. They are listed in order of effectiveness, highest to lowest. The three main types are shelf braces, span braces (many names for these) and corner braces. The shelf braces couple all four sides. Imagine putting a shelf inside of a sub box. It is connected to the front baffle, rear baffle and the sides. These are now coupled to create a single piece. When a brace is put in the vertical direction as well, you are gold. These braces have holes cut into them so as not to impede airflow within the cabinet, but not so much as the integral strength of the brace is jeopardized. The problem with shelf braces is that they take up precious Vb. If you don't have a lot of room to spare (most trunks are on space constraints //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ) read on. The next brace, the span brace, couples two sides together. An example is a 1.5 x .75 inch piece of wood running the distance from the front to the back. This only couples two sides which is better than nothing. Very commonly used in enclosures that are tight on space as they are more effective than the last brace, the corner brace. This is just a square piece of wood placed in the corner between two cabinet sides. These are not ideal as the probability that the brace is LITERALLY on the sides is nil (unless screwed in, when the glue dries it sometimes takes it away from the corresponding wood) and thus possible jeopardizing the effective bracing qualities of the brace. However, these take up very little room as well and are common in small bookshelf speakers where a shelf is obviously impractical and a span brace may impede either a port or the driver itself.
Wood itself is probably the second most important part of a speaker (you don't HAVE to use wood, as apparently the closest to natural speaker was an aluminum honey comb tower from the 1970s, according to various authors) next to the driver. Wood materials are VERY important when considering what you want the enclosure to sound like. Believe it or not, wood makes a sound when acted upon. For most enclosures, the relative stiffness of MDF as well as it's damping quality makes it very popular. However, to get truly the best sound for your money, a good plywood has always shown to be superior. These woods are rather expensive though. By plywood, I don't mean the chipboard used for underlayments, I mean the plywood that is multiple layers thick and resembles flooring. Baltic birch is a personal favorite of mine, as well as oak. The damping characteristics of the plywood are better and have a tendency to resonate LESS than MDF (as said by Small in an article from the 70's, just so u don't think i'm makin that up //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ). However, for most builders, MDF is ideal because it is relatively cheap, sounds good, is better than particleboard and can be easily found and cut.
"Take small signal .. make into big signal" //content.invisioncic.com/y282845/emoticons/waycrazy.gif.f4a380c3f94043939fd369defd9e6be2.gif
When cutting the cabinet, it is a good idea to cut a few millimeters or 1/8" wide for good measure. This way, you can have over hang OR you will be dead on the correct measurement. The only reason for this is because when using circular saws, or table saws inparticular, most people dont account for the blade which is usally 1/8 or more by itself. By cutting them wide, you have a margin of error and can then just throw in a flush trim bit on the router and go to town for a fine finish.
On my tablesaw, every cut I make is precision and the box is glued to perfection.
It's harder to do with a circular saw, jig saw, hand saw, etc. Tablesaw rules.
I think it's better to train yourself to do precision cuts than to settle for loose
tolerance cutting, eventually you will be happier this way as it's less work.
I mean the plywood that is multiple layers thick and resembles flooring. Baltic birch is a personal favorite of mine, as well as oak.
Baltic Birch at the local lumber store here is 14 ply, $202 for 3/4" , 4x8 sheet. /ouch
It's strong because of the laminations but will resonate in a similar fashion
to ordinary 7 ply wood, knock on it and you'll see [or hear it, hehe}.
Typical oak, birch, maple, etc plywood {$50/sheet} at the home centers
is 7 ply, the only thing 'oak', 'birch', 'maple', etc., about this wood is just the
very thin veneer, the inner layers are usually other types of cheaper
wood, perhaps fir or whatever. Because you pay premium for this 'veneered'
plywood, they try to make the quality of the sheet better with less voids to
because you expect it to be this way. If you don't need the fancy veneer
*and* can find good quality 'construction' grade plywood then it will perform
just as well for less money.
The damping characteristics of the plywood are better and have a tendency to resonate LESS than MDF (as said by Small in an article from the 70's, just so u don't think i'm makin that up //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ).
30 year old article? /hehe
MDF pros for loudspeakers;
* cheaper than veneered plywoods, marine plywood, baltic birch
* it doesn't warp like plywood
* weights 2x more than typical plywood which gives it a lower resonant frequency, damps higher frequencies better.
* machines well
* smooth surface for painting
Plywood pros for loudspeakers;
* more robust cabinets for other industries {DJ, proaudio, etc.}
* lighter weight + bracing can be very effective too.
* if veneered plywood, will finish well with stains, lacquers, etc.
What else?
When is your book going to be released ? //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
On my tablesaw, every cut I make is precision and the box is glued to perfection.
It's harder to do with a circular saw, jig saw, hand saw, etc. Tablesaw rules.
I think it's better to train yourself to do precision cuts than to settle for loose
tolerance cutting, eventually you will be happier this way as it's less work.
I mean the plywood that is multiple layers thick and resembles flooring. Baltic birch is a personal favorite of mine, as well as oak.
Baltic Birch at the local lumber store here is 14 ply, $202 for 3/4" , 4x8 sheet. /ouch
It's strong because of the laminations but will resonate in a similar fashion
to ordinary 7 ply wood, knock on it and you'll see [or hear it, hehe}.
Typical oak, birch, maple, etc plywood {$50/sheet} at the home centers
is 7 ply, the only thing 'oak', 'birch', 'maple', etc., about this wood is just the
very thin veneer, the inner layers are usually other types of cheaper
wood, perhaps fir or whatever. Because you pay premium for this 'veneered'
plywood, they try to make the quality of the sheet better with less voids to
because you expect it to be this way. If you don't need the fancy veneer
*and* can find good quality 'construction' grade plywood then it will perform
just as well for less money.
The damping characteristics of the plywood are better and have a tendency to resonate LESS than MDF (as said by Small in an article from the 70's, just so u don't think i'm makin that up //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ).
30 year old article? /hehe
MDF pros for loudspeakers;
* cheaper than veneered plywoods, marine plywood, baltic birch
* it doesn't warp like plywood
* weights 2x more than typical plywood which gives it a lower resonant frequency, damps higher frequencies better.
* machines well
* smooth surface for painting
Plywood pros for loudspeakers;
* more robust cabinets for other industries {DJ, proaudio, etc.}
* lighter weight + bracing can be very effective too.
* if veneered plywood, will finish well with stains, lacquers, etc.
What else?
When is your book going to be released ? //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
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