Sorry, I have been in speaker R&D for 2 days. 
Ok this is not pretty but it sounds great, although for some reason I can't seem to capture it's awesomeness. Like I said It's not pretty but here it goes, I have to build some thick baffles now so just ignore them, originally I was trying to relieve the area around the back of the driver but that didn't work out too well so I went this a way. And yes 4 drivers together lost all of their pin point accuracy. And since PVC pipe is actually foam cored I don't feel this is out of place here. Okay here goes Oh yeah, the pipe is stuffed from one end to the other including up tight to the driver. I ended up taking out one section at the end though. so 4-2" thick discs shoved into the pipe.
Heres a video of them in action
Video:
https://www.youtube.com/watch?v=h8fyNO5amnc
Pics:
Ok this is not pretty but it sounds great, although for some reason I can't seem to capture it's awesomeness. Like I said It's not pretty but here it goes, I have to build some thick baffles now so just ignore them, originally I was trying to relieve the area around the back of the driver but that didn't work out too well so I went this a way. And yes 4 drivers together lost all of their pin point accuracy. And since PVC pipe is actually foam cored I don't feel this is out of place here. Okay here goes Oh yeah, the pipe is stuffed from one end to the other including up tight to the driver. I ended up taking out one section at the end though. so 4-2" thick discs shoved into the pipe.Heres a video of them in action
Video:
https://www.youtube.com/watch?v=h8fyNO5amnc
Pics:
Attachments
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Is the PVC duct open back with foam stuffed in it then? I guess if you have a baffle why not go open baffle and have a foam stuffed duct behind? You don't want to hear the back wave? I am sure it sounds good but I think it will sound better if you build a triangular Dagger and find out for yourself.
Yep opened backed, I just have the cleanout thing so I could try it closed and to be able to adjust the stuffing. But open sounds best. I think once I get a 3" baffle setup it'll be much better as this one is way too flimsy. Kinda burned out on the whole experimentation thing. If i get sick of this setup or bored I might toss together a dagger. But at this moment all I want to do is sleep.. I wasn't real pleased with the tiny baffle sound, it was leaving a big hole between the fostex and the sub, with the big baffle it all jives just fine. so even if I did a dagger I would still need a big baffle.
I wasn't real pleased with the tiny baffle sound, it was leaving a big hole between the fostex and the sub, with the big baffle it all jives just fine. so even if I did a dagger I would still need a big baffle.
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open tube - -no damping in tube - high baffle step frequency
An externally hosted image should be here but it was not working when we last tested it.
It suppresses about 90% of the backwave. Question, So even if there is a cap on the driver which in this case is(68uf) wouldn't it begin to shut down the driver before the baffle step? I'm assuming this soley because when I use the baffle step calculator on quarter wave it gives me an f3 of 300hz with a 15" baffle (mines 24") . and when I calculate a low pass filter at 300hz it comes out to roughly 68uf.? So isn't my baffle larger than the baffle step?
I'll say this with the BSC and then the cap in line, it didn't sound to great. With just the BSC it was fine but the driver was going too low. With just the 68 uf cap I was the happiest at how it sounded. So that's how I ended up at this point.
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I forgot I shot this video of jazz brunch this morning. It sounds better than the last one..
https://www.youtube.com/watch?v=scnNzZret6M&feature=youtu.be
https://www.youtube.com/watch?v=scnNzZret6M&feature=youtu.be
With just the 68 uf cap I was the happiest at how it sounded. So that's how I ended up at this point.
I will never argue with a statement like this. Go for it! I just wanted to point out that for all practical purposes, you have build a sealed box with a baffle width of 24". But then the whole Nautaloss thing is about creating the perfect IB, i.e. a sealed box with zero reflections.
Again, not making any judgements, just saying....
Bob
I hope you try the Nautaloss or at least the straightened Dagger variant. It will sound better as it has to be better than a straight duct which will have some reflections from impedance mismatch at the terminus and if you are stuffing it tight with foam, it will be more open sounding without being open.
I'm betting the dagger will sound boxy, just like the tube sounded tubey, but stuffed it doesn't sound tubey. And I bet stuffed the dagger wouldn't sound boxy, but I do bet that they would both sound equally good And mine has some sound coming out the back, I wouldn't get that with the dagger, plus I would still need the large baffle.
And mine has some sound coming out the back, I wouldn't get that with the dagger, plus I would still need the large baffle.
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Bet you that the dagger doesn't measure boxy. Do you have a mic and measurement software? The triangle taper cannot support a standing wave in the same way a straight duct can. Look at the sims from a few posts back - the straight pipe will have larger reflections (source of boxy sound). But the important thing is that you THINK it sounds good
Anything is possible, I don't have measuring equipment except for my ears. but then again that's what really matters in the end right? I could always build a cone and mount it to one of the screw on cleanout caps, that would create a constant taper inside of the tube. shouldn't really matter which way the taper goes should it?Bet you that the dagger doesn't measure boxy. Do you have a mic and measurement software? The triangle taper cannot support a standing wave in the same way a straight duct can. Look at the sims from a few posts back - the straight pipe will have larger reflections (source of boxy sound). But the important thing is that you THINK it sounds good
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You mean a cone with vertex pointed at the driver mounted from the back of the PVC pipe? Well the only thing is the length of 12 in is not ideal like a 3 ft long one. It can't hurt though but it does decrease your volume significantly. Slapping 5 pieces of wood together to form the Dagger is not that hard. You should just try it with hot melt and foam core and then it will really be easy. It will work just as well as wood for the purposes of absorbing the back wave like an acoustic black hole. Better yet, build a spiral Nautaloss out of foam core and listen for yourself.
Yep with the point heading towards the driver. But I'm not getting the jist of why it needs to be 36" long? I will agree with you 100% that the taper would not support a standing wave though,. And that would be a good thing. But before I do anything I need to construct some nice solid baffles so I'm not confusing baffle noises with boxy, tubey sounds. Then I will go on to the tapered dagger to check the sound of them.
The longer length gives the taper more room for it to do its thing in terms of absorbing the back wave and being more "open" and less box like but not sustaining a mode like a long rectangular box. Why do you need such a large thick front baffle? Are you trying to get the baffle cutoff freq low enough to cross with the 200 Hz from the sub?