This thread for me better and more interesting that any TV channel i can receive, and now with added fine humor, splendid and thank you diy members.
🙂 Yep , start with building something simple, then use that to build something a little more complicated ... repeat, gain experience, learn from mistakes etc. ... 🙂
I use the hallway for the dirty work, the living room has better lighting for photography.
The store cut the 4'x8' sheet into four 2'x4' sheets for me, the rest was done at home. So far I have made/use two straight edges, one for the circular saw and one for the router, plus a circle cutting jig. And now a router table 🙂 No table-saw as yet... thinking a band-saw might useful also.
As for the Nautaloss... will need to re-make the template, an aluminium one would be nice but costly to have made. Going to make the wall of the outer curve thicker and make sure the feet give better stability.
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Just get a sheet of aluminium 1 mm thickness, you can cut thin strips with good scissors.
Use that on the template where the bearing of your router bit follows the template.
That will make the template last for more than 2 copies 🙂.
Use that on the template where the bearing of your router bit follows the template.
That will make the template last for more than 2 copies 🙂.
Nice! 
How do you handle the sawdust? You just make a mess in the hallway and sweep up afterwards?
How do you handle the sawdust? You just make a mess in the hallway and sweep up afterwards?
Normally sweep up afterwards, but do use the vacuum attachments as much as possible in an attempt to keep the mess to a minimum... Still, MDF dust gets everywhere no matter what you do 🙁
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Decided that I'm going to make the Nautaloss the 5 part of my 5.1 HT setup... will need to work out passive BSC for them also ... Still working out how I want to proceed with my main music only speakers.
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Decided that I'm going to make the Nautaloss the 5 part of my 5.1 HT setup... will need to work out passive BSC for them also ... Still working out how I want to proceed with my main music only speakers.
The baffle dimensions of the Nautaloss are similar to the Vifa DCR which uses a 1.0 mH + 10 ohm + 0.47uF all in parallel. This worked pretty nice. If you want it a bit brighter, use a 5 ohm resistor.
Some ideas for the Twin Peerless enclosure...
Left design ... note the front chamber tapers towards the base, so expanding slightly before going into the rear pathway... ~ 7 foot pathway.
Middle design ... full tapering pathway ~ 7 foot long.
Right design ... based on the B&W 802 Diamond enclosure.
All three are ~46L sealed enclosures and would give an F3 of ~50Hz at 90dB 1W/m... Room gain would lower F3 again. With EQ and limiting SPL, F3 can be lowered still.
With the amount of stuffing required in the tapered design, actual Vb would be more like 38L than 46L to keep system Q at ~0.707
Left design ... note the front chamber tapers towards the base, so expanding slightly before going into the rear pathway... ~ 7 foot pathway.
Middle design ... full tapering pathway ~ 7 foot long.
Right design ... based on the B&W 802 Diamond enclosure.
All three are ~46L sealed enclosures and would give an F3 of ~50Hz at 90dB 1W/m... Room gain would lower F3 again. With EQ and limiting SPL, F3 can be lowered still.
With the amount of stuffing required in the tapered design, actual Vb would be more like 38L than 46L to keep system Q at ~0.707
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BMS,
Neat design... a few comments...
I would not make the TL so long as that will tend to set up a possible resonance in the bass region where you want to avoid the resonance. I think a 48 in long TL is sufficient and will keep the resonances higher in freq where you won't care. Also, it will make it smaller. If you are using the 830869 Nomex drivers, I think a 20 in tall x 10 wide baffle where the dual drivers mount and then the rear extending to a point 48 in away like a dagger (and now you can coil or fold as you have done) should give you an f3 closer to 31 Hz. If you want to build it like you have just make sure you don't have a parallel wall directly behind driver. So I would actually have the area directly behind the driver open and going back then turn 90 up and then fold as you are doing with a 180 deg turn down then up again - whatever it takes to get to 48 in. Also, doesn't stuffing actually produce a larger apparent Vb?
Neat design... a few comments...
I would not make the TL so long as that will tend to set up a possible resonance in the bass region where you want to avoid the resonance. I think a 48 in long TL is sufficient and will keep the resonances higher in freq where you won't care. Also, it will make it smaller. If you are using the 830869 Nomex drivers, I think a 20 in tall x 10 wide baffle where the dual drivers mount and then the rear extending to a point 48 in away like a dagger (and now you can coil or fold as you have done) should give you an f3 closer to 31 Hz. If you want to build it like you have just make sure you don't have a parallel wall directly behind driver. So I would actually have the area directly behind the driver open and going back then turn 90 up and then fold as you are doing with a 180 deg turn down then up again - whatever it takes to get to 48 in. Also, doesn't stuffing actually produce a larger apparent Vb?
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Stuffing will lower, not raise the Q, unless it's overly dense, in which case it mostly just takes up volume with relatively little absorption.
Re length, depends. A long sealed TL is fine providing it's properly damped & well matched to the driver. They have been commonly employed in various forms since the 1930s in commercial audio (not popular but exists, e.g. B&W, Monitor Audio &c.) & in manufacturing / testing (plane wave tubes, popular for measuring compression drivers for example).
Re length, depends. A long sealed TL is fine providing it's properly damped & well matched to the driver. They have been commonly employed in various forms since the 1930s in commercial audio (not popular but exists, e.g. B&W, Monitor Audio &c.) & in manufacturing / testing (plane wave tubes, popular for measuring compression drivers for example).
Thanks both,
X, path length just happened to be that for those configuration and easy to shorten. Can remember you said between 4 and 6 feet would be OK. It was more about which layout might be appropriate.
Yes, sorry my poor way of explaining things again. To get a Q of 0.707 for the B&W 802 inspired enclosure with minimum stuffing would require ~46L [48L effective Vb]. For the tapered two, 38L unstuffed Q is ~0.78, with ~65% stuffing it's effective Vb rises to 48L and Q drops to 0.707 ... That's using Basta! and specific to twin 8" Peerles drivers.
Good communication is not my forte, that's why I draw things, it takes less time than writing a paragraph 😀
X, path length just happened to be that for those configuration and easy to shorten. Can remember you said between 4 and 6 feet would be OK. It was more about which layout might be appropriate.
Yes, sorry my poor way of explaining things again. To get a Q of 0.707 for the B&W 802 inspired enclosure with minimum stuffing would require ~46L [48L effective Vb]. For the tapered two, 38L unstuffed Q is ~0.78, with ~65% stuffing it's effective Vb rises to 48L and Q drops to 0.707 ... That's using Basta! and specific to twin 8" Peerles drivers.
Good communication is not my forte, that's why I draw things, it takes less time than writing a paragraph 😀
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6 ft should be fine, just make sure you set the volume and Q appropriately to get bass extension you want and cone excursion control you want. I was trying to keep the box smaller by going with shorter path. You have a good plan and I look forward to seeing how this works out.
Since volume is presumably (sorry, I haven't had chance to read all the thread) derived from a chosen sealed box Qtc, the length of the TL shouldn't have much impact on the size of the box, short of a little extra for the volume taken up by the panels. (?) Or are you fixing the nominal line 1/2 wave resonance as = system resonance in a given sealed volume / Q?
Either way, likewise, be very interesting to see how you get on.
Either way, likewise, be very interesting to see how you get on.
From what X has explained, the volume is derived from the chosen sealed box Qtc and has given an approximate length for the TL. The main instance has been for ~4" drivers in a sealed box, but expanded upon for use with woofers 🙂
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So this is going to be with the Peerless 830869? I'm using a pair in essentially MLTL boxes, along with BMS 4540ND and small JBL PT-waveguide. They should do well in sealed boxes and can take some EQ if needed.
At the risk of sounding like a heretic, you could do worse than a low-tuned EBS (recent convert here for woofers 😉 ).
Extended Bass Shelf?! overly large ported enclosure tuned to roughly the drivers Fs, giving a slow frequency roll-off rather than flat response and using room gain?!
Though I didn't know it had a name, I've simulated something similar in Basta! Only thing that put me off, is not knowing how suited a ported system [downward firing] is for use in corner-of-the-room placement. Active XO & EQ could be a God send for this type of build.
Though I didn't know it had a name, I've simulated something similar in Basta! Only thing that put me off, is not knowing how suited a ported system [downward firing] is for use in corner-of-the-room placement. Active XO & EQ could be a God send for this type of build.
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