I just had extra pvc laying around from a potato launcher I built 2 weeks ago. The prototype is just to get an initial feel, for how I can expect the speakers to perform, and I think it was a great success. The caps arn't even sealed on the pipe, just a dry fit. I am planing on building Zaphs's boxes.
Besides my design goal is to make a nearly disposable speaker, not a really high quality build. The speakers are going to be exposed to alaska oceans and extreme weather. I have a pair of nice PSB's for my apartment that don't need to be replaced.
I'll post some videos after work
Besides my design goal is to make a nearly disposable speaker, not a really high quality build. The speakers are going to be exposed to alaska oceans and extreme weather. I have a pair of nice PSB's for my apartment that don't need to be replaced.
I'll post some videos after work
hope this is not redundant
this is from Zaphs build page:
"I don't know where I got a Bennic Poly 4.3 uF cap, nobody sells them. 4.7 is too big and 3.9 is too small for this. You can parallel a 1.0 and 3.3 to reach this value however. "
but now Parts /Express has these:
4.3 - Parts Express Ships Fast and Ships Free.
If the link does not work, just search PE website for "4.3uf capacitor"
Howard
this is from Zaphs build page:
"I don't know where I got a Bennic Poly 4.3 uF cap, nobody sells them. 4.7 is too big and 3.9 is too small for this. You can parallel a 1.0 and 3.3 to reach this value however. "
but now Parts /Express has these:
4.3 - Parts Express Ships Fast and Ships Free.
If the link does not work, just search PE website for "4.3uf capacitor"
Howard
You probably missed something while posting the link to the URL. Here it goes:
Dayton Audio DMPC-4.3 4.3uF 250V Polypropylene Capacitor
Dayton Audio DMPC-4.3 4.3uF 250V Polypropylene Capacitor
Modern flat screen TVs are slim, which doesn't leave much room for speakers. That's why they all have poor sound. External boxes are always a great improvement.
As for the sub-woofer, if you haven't seen this project, it gives good results for its low cost. I built it in a box with the equivalent volume to have a better looking unit.
Subwoofer
As for the sub-woofer, if you haven't seen this project, it gives good results for its low cost. I built it in a box with the equivalent volume to have a better looking unit.
Subwoofer
subwoofer
Grimberg,
I was recently looking at the SLS woofers. Seems like good value in these drivers.
The bucket as enclosure is interesting approach. I have woodworking tools, so a wood box is my choice too, but the bucket is a nice option for those without easy access to tools and appropriate work-space.
The bucket is interesting in another way---in a way it is an aperiodic type of enclosure-due to the flexing of the walls. Also the plastic will re-radiate energy in a different way than wood.
I smiled as I remembered a speaker that I made for my teenaged backyard hide-out. It was a 1950's Jensen alnico 8" set into the top of a metal milk can--about 15 gals or so? I ran zip cord for about 75ft and put on a reel to reel tape from my room in the house. That was a nice sounding speaker. Wish I still had it.
Grimberg,
I was recently looking at the SLS woofers. Seems like good value in these drivers.
The bucket as enclosure is interesting approach. I have woodworking tools, so a wood box is my choice too, but the bucket is a nice option for those without easy access to tools and appropriate work-space.
The bucket is interesting in another way---in a way it is an aperiodic type of enclosure-due to the flexing of the walls. Also the plastic will re-radiate energy in a different way than wood.
I smiled as I remembered a speaker that I made for my teenaged backyard hide-out. It was a 1950's Jensen alnico 8" set into the top of a metal milk can--about 15 gals or so? I ran zip cord for about 75ft and put on a reel to reel tape from my room in the house. That was a nice sounding speaker. Wish I still had it.
flexing
Hi Dave,
So, the cylinder is a good shape for a sub woofer enclosure with minimal wall thickness.
That indicates that whatever movement there is in the bucket enclosure membrane around the cylinder--such as vibration that you can probably feel when it is playing loud, is likely the plastic stretching? The top would probably flex up and down a bit. The bottom is secured with concrete.
And a sphere?
Hi Dave,
So, the cylinder is a good shape for a sub woofer enclosure with minimal wall thickness.
That indicates that whatever movement there is in the bucket enclosure membrane around the cylinder--such as vibration that you can probably feel when it is playing loud, is likely the plastic stretching? The top would probably flex up and down a bit. The bottom is secured with concrete.
And a sphere?
aspect ratio
Is there an aspect ratio where an enclosure stops/starts behaving like a pipe?
The MLTL low cut-off is directly related to it's length, but also to the dimensions of the port?
I have been intrigued to see comments/data that in some enclosures different size drivers of similar type(up to a reasonable degree of size variation I'm sure) can work similarly in a given ported-box/horn/pipe. The position of the driver in a pipe seems to be really important to optimizing the design.
I have noticed that a big driver in a small (sealed or ported) box tends to have a boomy peak before it rolls off. I assume this would be true for a TL, MLTL?
Is there an aspect ratio where an enclosure stops/starts behaving like a pipe?
The MLTL low cut-off is directly related to it's length, but also to the dimensions of the port?
I have been intrigued to see comments/data that in some enclosures different size drivers of similar type(up to a reasonable degree of size variation I'm sure) can work similarly in a given ported-box/horn/pipe. The position of the driver in a pipe seems to be really important to optimizing the design.
I have noticed that a big driver in a small (sealed or ported) box tends to have a boomy peak before it rolls off. I assume this would be true for a TL, MLTL?
The BR math assumes a box with dimensional ratios not that far off from a cube. As one dimension starts to significantly grow and the other 2 shrink, the box will slowly transition from a BR to an ML-TL. I have boxes where i purposely work to defeat the ¼ wave behavior (the Compact FLoor Stander miniOnkens) and visa-versa one can work to enhance the ¼ wave action (the big Woden ML-TL for the GPA 604).
Here is a picture collaged together from Martin's ANSYS simulation of a BR vrs his 1st ML-TQWT which clearly shows the different characteristics caused by a stretching the box... both have the same driver, volume & port -- the only difference is shape.
Yes. The port/restricted terminus supplies some extra pole(s) to the Low Pass function of the pipe and where this is is determined by its size.
The Zd of a driver can be such that it acts to kill off one of the unwanted harmonics (usually best to traget the lowest one) to further improve the low-pass function of the terminus. This and the mass-loading given by a restricted terminus means less damping is required to get smooth response and more bass enhancement can be realized by the primary ¼ wavelength resonance.
That is all design dependent. A driver in a box significantly smaller than its Vas will peak at the bottom and have an underdamped response. Adding a reflex port typically just makes this worse.
dave
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