-of course don't forget that you are still "gating/windowing".
(..and will need to do a near-field measurement for freq.s lower than 300 Hz.)
Still, what you are typically "shooting" for here is about 500 Hz for most of the baffle effects on dispersion. (..for a typically "narrow" baffle loudspeaker.)
Note: the results of the rear of the open-box will look weird.
Yeah I still have to gate, I have noticed by doing so it smooth the frequency response but I suppose I should not have too much invisible dip & peaks because of that
Yep near-field at -20db, will not forget
I don't understand what you mean by shooting for 500Hz, do you speak about the accuracy of the measurement ?
So at first measuring on just the front baffle without box there is not point passing 90° and even I should get some wave cancellation in some frequencies because it's a narrow baffle and back-wave will cancel front-wave (if I understand right)
I suppose It's only when the cabinet is complete that this can be useful to measure 180°
So when you say weird at the rear is it about that Mid High open cabinet or just the front baffle ?
500 Hz presents a lower freq. limit where most diffraction effects for typical speakers are relatively uniform. As you go higher in freq. diffraction effects start becoming less uniform.
-of course with your loudspeaker design that's not true because of the open-box design: the dispersion pattern toward the open-rear of the loudspeaker (for mid + tweet) will look quite different: showing a lot of diffraction artifacts that won't look anything like the frequency response of the front/baffle of the loudspeaker. (ie. "weird" looking.)
..and yes, 180 degrees for the loudspeaker box. About 72 degrees for a test baffle.
-of course with your loudspeaker design that's not true because of the open-box design: the dispersion pattern toward the open-rear of the loudspeaker (for mid + tweet) will look quite different: showing a lot of diffraction artifacts that won't look anything like the frequency response of the front/baffle of the loudspeaker. (ie. "weird" looking.)
..and yes, 180 degrees for the loudspeaker box. About 72 degrees for a test baffle.
Ok clear to me now thanks
I hope that 100uf capacitor is enough to protect that tweeters when I will make measurements, If I measure it at around 75dB taking into account the natural roll-of of the driver it start to go down at 378hz and reach 55Hz at 40dB
I'll have to help my parents to pack & move to a new place, once that is done I'll begin working on the front baffle, I really need to start making some progress
Hi Scott,
It's a long time already, how are you?
I have started the front baffle boards, cutting, and glue them together, I did some routing but it's more difficult than I thought to be precise when cutting, that depth slider isn't holding very well so I have to start again, tweeter cutout is not accurate enough I can't see very well where is my router bit
I'll do a few hours every Saturday it's slow but hopefully I will end up with something that pass my quality expectation.
I find it more difficult to cut squares for the tweeter wave-guides, I'm happy I started with the cheapest MDF I could find!
Have a nice Weekend
It's a long time already, how are you?
I have started the front baffle boards, cutting, and glue them together, I did some routing but it's more difficult than I thought to be precise when cutting, that depth slider isn't holding very well so I have to start again, tweeter cutout is not accurate enough I can't see very well where is my router bit
I'll do a few hours every Saturday it's slow but hopefully I will end up with something that pass my quality expectation.
I find it more difficult to cut squares for the tweeter wave-guides, I'm happy I started with the cheapest MDF I could find!
Have a nice Weekend
-good enough.
I just started on my dipole bass baffle today. (..I got side-lined with a *project that got "binned" yesterday.)
*DirecTV (satellite TV provider raised their rates more than double, and I was planning on ditching them this month - scrambling to get an alternative up before then, when they called-up and offered the service at $10 less than I was paying before: so now I've got to return a bunch of stuff I ordered.)
I just started on my dipole bass baffle today. (..I got side-lined with a *project that got "binned" yesterday.)
*DirecTV (satellite TV provider raised their rates more than double, and I was planning on ditching them this month - scrambling to get an alternative up before then, when they called-up and offered the service at $10 less than I was paying before: so now I've got to return a bunch of stuff I ordered.)
That's a bummer.
Yeah, it's definitely a matter of practice and the "jig's" you use (and often create yourself).
Square cuts? Saw.
(..of course if it's an "internal" cut, then it's usually jigsaw with a guide/jig and a fair bit of small-block hand-sanding.)
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Great news, do you plan to share some details about that dipole baffle ?-good enough.
I just started on my dipole bass baffle today. (..I got side-lined with a *project that got "binned" yesterday.)
That seem to be a good news in the end, had a look on the DirecTV website out of curiosity and none of the channels are available here, but I rarely watch any I have here anyway I can't bear the amount of advertising and the content is old compared to what I can get on Internet.*DirecTV (satellite TV provider raised their rates more than double, and I was planning on ditching them this month - scrambling to get an alternative up before then, when they called-up and offered the service at $10 less than I was paying before: so now I've got to return a bunch of stuff I ordered.)
That's a bummer.
Yeah, it's definitely a matter of practice and the "jig's" you use (and often create yourself).
Square cuts? Saw.
Yes my Jig's game is really nowhere, I have the one that is delivered with the router but it's quiet limited what I can do with it.
I have seen a few video about making a circle cutting Jig for small and big radius but I have yet to find which I will make, I wish I could buy one that fit my router so I don't have to spend extra time on that.
The square is to flush the Radian Waveguide, so I have to use a router, I either have to buy the Triton guide bushes kit but I find it very expensive for what it is, or buy myself a straight bit with a bearing on top so I can cut myself a guide with a jigsaw to limit my cut
I ended up going out of lines, can't see very well where the bit is in relation to the markings through that plexi and I have to be more gentle when plunging so I don't force that depth limiter beyond what I set.
The baffle I just routed is barely large enough to mount the two 15" drivers (..still have to drill the bolt-mounts). Once I've figured-out orientation in-room it will get attached in a much larger "baffle" path-length (for phase cancellation/dipole) under the rear seats for the HT. Basically a tiny baffle mounted on a much larger "baffle" that utilizes the room floor and the raised seating area floor.
Advertising sucks.
..but it's what pays for all those new-content shows. Plus, I pretty much record everything and then FF through the commercials. It's super annoying with Movies that have been chopped-up, BUT with DirecTV they usually have a weekend every quarter with free access to premium channels like HBO, and at that time you just record every movie you are interested in. It works out for my family in particular because of the integrated guide (both local channels and "cable" channels on the same guide). The solution I was looking at to replace it was "over-the-air" for local broadcast channels (plus an automatic commercial skip solution from MythTV) and then adding-on SlingTV Blue w/DVR for that. While there is an ability to integrate them both on the same guide, you can't really do that AND have a complete commercial skip result for local channels. Except for hardware costs it would have been cheaper still, but several android TV boxes plus a PC server to record local shows would have added at least $600 done the way I wanted. DirecTV (for at least a year then) will be about $47 a month with taxes (where before it was close to $60). This last month after the price hike it was near $130 a month (but I got a $70 rebate for the last month as well). So at least I have it cheap"ish" for a year. Tried to get a lower rate on my internet (which is about $60 a month), but no luck there - no real alternatives in my area (..sort of "p!$$!ng in a pond").
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I just did this for my 15" driver holes.
Here you are making a new "base-plate" for your router (you do NOT use the base plate on your router, but you do use the screws that the plate is using for attachment to your router).
Had some floor ceder plank scrap wood (the type used in closets to keep bugs out) that was reasonably thin (slightly thicker than my router's base plate) and just wide enough for 2 of the 3 mounting screws that the router base-plate uses. Note: you need two mounting points as a minimum, but preferably as many as your router has. In this case though my scrap wood wasn't wide enough to accommodate all 3 mount-points.
Marked-out center on the board and then drilled a hole large enough for a phillips head screw driver to slide into it firmly. Made an identical hole for the ceder plank on one end. Made sure the screw driver would fit/couple the two boards together but still allow for rotation.
Measured from the center of that baffle hole out to half of the driver's diameter and then subtracted the amount for the mounting "lip" of the driver and made several lines showing where the router hole would be with the ceder plank covering that hole area. Then put the ceder plank onto the board with the screw driver in the center hole, and then marked the location for the router bit hole on the ceder plank. Drilled the (slightly larger than) bit-sized hole through the plank and board.
Then I pulled the plank off (pulled out the screw driver) and then mounted the plank on the router's bit. Moved it back and forth until I found where two of the base-plate holes would fit on the plank, drilled them and then used a counter-sink drill bit to allow the base-plate screws to mount flush (slightly inset actually) to the board. Attached the ceder plank to those base-plate screw holes with the base-plate's screws (..basically replacing the base-plate).
Finally: put the router bit through the router "outside" hole on the board to be cut and moved the plank to where the other holed lined-up with the center hole and pushed the screw driver through it.
Then I powered up the router and cut the circle.
..and did the other hole (though much easier, just taking off the ceder plank from the router and using it as a guide for the two other holes for the other 15" diameter hole).
..though in my case the two 15" holes I cut weren't quite lined-up, so one of the drivers is going to be slightly off-set from the other.
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Yes, that's much more difficult, and usually involves a chisel for the corners.
-at least you have a plunge router.
You can just make a large "frame" for the cut/routing. Clamp the frame to the board being cut and then push the router against the inside of the frame and cut at the correct depth. Then go back and chisel the corners as needed.
I think you are now used that I have some trouble picturing that in my head
Advertising sucks.
Wow, I'm quiet impressed of the elaborate thought process you put into this to watch television, look like you have a knack to find projects to keep you busy
Here there are not enough content on distributors that I value enough to watch, so, once I had SyFy channel but they removed it, since then it's mostly re-diffusion or stuff that are at least a year old.
In the end I watch my movies sitting on the computer chair with a headphone, the computer display is better than my 10 year old plasma television anyway.
One thing I am trying to do is to digitize a few VHS I have, unfortunately the ION VCR2PC USB recorder is quiet old and I have yet to succeed find a solution, I have tried setting up a small Fujitsu Q900, No luck on Win10, Win7x64 or XP32, the device is still shown as "unknown" in the USB controllers, I have tried all the ways to install the driver without success, I will maybe try to find myself a Win7 32bit, but I spent to much time on that already.
I just did this for my 15" driver holes.
Here you are making a new "base-plate" for your router (you do NOT use the base plate on your router, but you do use the screws that the plate is using for attachment to your router).
Had some floor ceder plank scrap wood (the type used in closets to keep bugs out) that was reasonably thin (slightly thicker than my router's base plate) and just wide enough for 2 of the 3 mounting screws that the router base-plate uses. Note: you need two mounting points as a minimum, but preferably as many as your router has. In this case though my scrap wood wasn't wide enough to accommodate all 3 mount-points.
Marked-out center on the board and then drilled a hole large enough for a phillips head screw driver to slide into it firmly. Made an identical hole for the ceder plank on one end. Made sure the screw driver would fit/couple the two boards together but still allow for rotation.
Measured from the center of that baffle hole out to half of the driver's diameter and then subtracted the amount for the mounting "lip" of the driver and made several lines showing where the router hole would be with the ceder plank covering that hole area. Then put the ceder plank onto the board with the screw driver in the center hole, and then marked the location for the router bit hole on the ceder plank. Drilled the (slightly larger than) bit-sized hole through the plank and board.
Then I pulled the plank off (pulled out the screw driver) and then mounted the plank on the router's bit. Moved it back and forth until I found where two of the base-plate holes would fit on the plank, drilled them and then used a counter-sink drill bit to allow the base-plate screws to mount flush (slightly inset actually) to the board. Attached the ceder plank to those base-plate screw holes with the base-plate's screws (..basically replacing the base-plate).
Finally: put the router bit through the router "outside" hole on the board to be cut and moved the plank to where the other holed lined-up with the center hole and pushed the screw driver through it.
Then I powered up the router and cut the circle.
..and did the other hole (though much easier, just taking off the ceder plank from the router and using it as a guide for the two other holes for the other 15" diameter hole).
..though in my case the two 15" holes I cut weren't quite lined-up, so one of the drivers is going to be slightly off-set from the other.
If I understand it well it's something like that I had in mind, at first I thought of making an adjustable point on a small wooden block for the compass held with with a washers, bolts & nuts with a butterfly head, but I can do that another time, I also wanted to make a way so my router could spin freely while rotating the compass with some kind of guide bush inserted in the jig, but that also would set me back to make progress on my baffles.
I have also to make a bigger circle about 20" diameter to use as a base for the turn-table, noticed also that the cheap big protractor I bought was not really accurate, 90° is not exactly 0 on it I'll have to make do
Yes, that's much more difficult, and usually involves a chisel for the corners.
-at least you have a plunge router.
You can just make a large "frame" for the cut/routing. Clamp the frame to the board being cut and then push the router against the inside of the frame and cut at the correct depth. Then go back and chisel the corners as needed.
Yes, spot on, that was my plan to use to limit the mess I can do, I thought of also buying a bit with a bearing on top to guide the cut but it's cheaper to use the router base as a limit.
I have some old Chisel that I can sharpen for the corners
I think you are now used that I have some trouble picturing that in my head
-when I get to that point I'll snap a picture to keep as part of the grouping I already have for this build log.
(..at some point I'll create a thread.)My current problem is mounting the spring-loaded "posts" for the sub on this panel.
After that's done I'll have to "brace" the panel to strengthen it (..the panel I used is just to thin without support).-when I get to that point I'll snap a picture to keep as part of the grouping I already have for this build log.
My current problem is mounting the spring-loaded "posts" for the sub on this panel.
Yes, you know how goes the say, a picture is worth a thousand word
Are the binding post not long enough to go through the panel ?
Perpendicular bracing that hold the back of the driver?
I imagine that for a 15" sub it need to be quiet rigid, a steel plating ?
..it's this cheap set:
Spring Loaded Speaker Terminal Nickel 13/16" Tab
It's designed for a mounting plate (thin and ridgid).
I'll just be mounting "on" the baffle, so I'll look to some thin (but rigid) material and electric tape for isolation. Honestly though, this is another one of those moments where I dearly wish I had a good 3D printer. (..I keep waiting for a larger build-volume on a cheap SLA (LCD) printer that has gone through at least a couple of design iterations. The LCD variety all use phone screens, and there are some larger screens that are being used now in phones and tablets that should make it to printer-use.)
Bracing will be rather like doing a stud wall in a home (where the sheet-rock panel is the baffle), though I might do the "framing" on both sides of the panel/baffle. Cheap implementation.. because it's HT (..and I don't care that much). No one's every going to see it though, so I don't have to care about how it looks (..when compared to a typical baffle). The one thing I do care about though is how high the overall structure (with drivers) is going to be: I can't raise the platform to much that this sub will be under.
Spring Loaded Speaker Terminal Nickel 13/16" Tab
It's designed for a mounting plate (thin and ridgid).
I'll just be mounting "on" the baffle, so I'll look to some thin (but rigid) material and electric tape for isolation. Honestly though, this is another one of those moments where I dearly wish I had a good 3D printer. (..I keep waiting for a larger build-volume on a cheap SLA (LCD) printer that has gone through at least a couple of design iterations. The LCD variety all use phone screens, and there are some larger screens that are being used now in phones and tablets that should make it to printer-use.)
Bracing will be rather like doing a stud wall in a home (where the sheet-rock panel is the baffle), though I might do the "framing" on both sides of the panel/baffle. Cheap implementation.. because it's HT (..and I don't care that much). No one's every going to see it though, so I don't have to care about how it looks (..when compared to a typical baffle). The one thing I do care about though is how high the overall structure (with drivers) is going to be: I can't raise the platform to much that this sub will be under.
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I hooked-up and tried my sub's (two 15" mentioned before) on-mini-baffle to see what the load ("booming") would be like in-room and beyond.
Overall it worked well, no booming into other rooms in the house. (..advantage of a dipole).
Disadvantage for the dipole was of course excursion. Going well beyond xmax with LOUD bass-effect transients. If not for the VC leads on one of the drivers (that are "sagging" down toward the cone to much), there was no audible problem. (..with the reward/return stroke the cone hits the leads and makes a "pop" with really loud transients). I'm going to have to figure-out how to keep them bent toward the frame rather than the cone. Other than that the driver's work well for my purpose. (..I guess as a last resort I could trim them and resolder to the terminal.)
Overall it worked well, no booming into other rooms in the house. (..advantage of a dipole).
Disadvantage for the dipole was of course excursion. Going well beyond xmax with LOUD bass-effect transients. If not for the VC leads on one of the drivers (that are "sagging" down toward the cone to much), there was no audible problem. (..with the reward/return stroke the cone hits the leads and makes a "pop" with really loud transients). I'm going to have to figure-out how to keep them bent toward the frame rather than the cone. Other than that the driver's work well for my purpose. (..I guess as a last resort I could trim them and resolder to the terminal.)
Funny, you have the same issue I had with the Infinity Sub-woofer in my car, the leads hitting the aluminum membrane, my fix was to attach rubber band from the leads to the frame. I don't know the longevity of that workaround because it's the car that didn't last...My Citroen was no match for the heavy VW
Great news that the sub-woofers are aligned with your expectation, do you loose much sensitivity from that 92db by going dipole ?
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