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- Analogkid455 9:45AM
- jholtz 9:45AM
- rjj45 9:46AM
- Tom_S 9:46AM
New project - The Chiquitos
I am starting a new project that will use a pair of the brand new MAC-04 drivers. I am calling this project The Chiquitos. That is Spanish for "Little Ones". While these won't be super tiny they will be pretty small at just 5 Liters and some change. They will be a basic ported two way design with the MAC 4" woofer and a Beston RT003C round ribbon tweeter. The tweeter will force a fairly high crossover point but I think the two drivers will work well together.
The box model indicates an F3 point of 56 Hz with a smooth and shallow rolloff which isn't bad at all for a 4" woofer. Here is the modeled box response at 10 Watts:
I am using 1.5" diameter PVC for the ports. The box model shows that there will be a port resonance somewhere above 1kHz. Because of that I am going to try Scott Sehlin's port resonance damping technique again (it worked for me before). I will drill a series of small holes around the port at the mid point and another series of holes at the 1/4 length, then wrap the port with some light damping material.
Comments
Here is the baffle layout with 3/4" round overs on all 4 edges:
Made the port tubes over lunch:
I'm interested in your thoughts on the Beston tweeter. I've got it penciled in for my next project. I know I've heard it few times, but don't recall if gave a ribbon like performance.
It has a sound all its own, but I like it.
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Wolfy's Photobucket
Its sound is definitely more ribbon like than dome like IMO.
John, you may have heard it in my 3 way project, two years ago at Indy. The woofer was the SD215A and the mid was the TC9FD. It was my project with the grills and the 1/2" felt on the baffle.
Yeah, maybe, thanks. I think Chuck used it with a Faital Pro. I'll have to do a test and compare against the OT19
Ben also used it in his Stances project many moons ago.
The enclosures are built sans the removable hardwood baffles. It's supposed to get pretty darn cold here starting tonight, and even some snow on Tuesday for trick or treating. But then a slight warm up at the end of the week so I should be able to get the project to the point of measuring/voicing/measuring/voicing/etc.
Finishing the enclosures and baffles will have to wait several months at least. I really look forward to measuring and hearing these new MAC-04's. They sounded clean and clear as midrangers in JR's 3 way project last weekend in Iowa.
I have to say, building smaller speakers is way more fun than building towers.
Why do you think I do so much of it?
1- they take up less room.
2- they take less material.
3- they really are more fun!
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Wolfy's Photobucket
Nope, with the Faital pro, I used the Dayton AMT2-4. I did use the beston one year with a Dayton rs150 in the "Pipe Dreams"
Just to be clear, that got a WTF from me.
It is a nice reprieve from dealing with the extra size and weight the whole time during construction and finishing. If small enough, each step is hardly "work" by comparison.
Yeah, small speakers are fun and surprisingly difficult to get "right".
For me it might be a seasonal preference, as I prefer to rout outdoors... and we have snow
Me too. I do all of my router work, as well as table saw work, outside on my driveway. I've been known to be out there machining baffle with the temps around 30F. Sucks but don't want all that dust in the garage or house.
Nice ports. I'll be doing that again. There's not much downside.
Sehlin Sound Solutions
I wonder if slash cutting the inner end would help flatten/broaden the resonance peak too.
Consider how mufflers work on automobiles and suppressors work on firearms and I think therein lies a lot of possible answers . . . we are dealing with pressure waves . . .
My thought is it would create a varying length so it broadens the frequencies that are excited within the tube. Typically when that happens the energy is spread across that range rather than focused towards a single frequency.
A bend in the pipe would also do this a bit since the inside circumference of the bend is shorter than the outer circumference.. From a side view.
An angled or 45° off the end of the port works like a roundover or flare. The tuning is at the center line length.
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Wolfy's Photobucket
Not sure if this discussion/experiment addresses the concern here but take a look at this --> https://www.diyaudio.com/community/threads/investigating-port-resonance-absorbers.388264/
So these oak baffles are just rough cut. Obviously lots of sanding to do and then the final finishing process. Just thought I would share
Hmm? Having a bit of a hard time posting pictures from my phone today. Will update this tread tomorrow from my work computer.
The gray paint on the cabinets is actually much darker when not under all the LED lighting of my workbench. I'd say it's more charcoal grayish.
Project ready for measurements!
Damn, that was fast!