See if this works.Congrats!
Is this with the Altec PC subwoofer? Wait until you put a real sub that is clean next to it.
Good ideas for a wood build with side and front panels - all easy cuts. Not sure why you want to kerf the outside (convex) side of the foam core. Mine curved nicely with the scoring on the concave side and it leaves it smooth that way. Good idea on the tube - I thought of using a paper roll tube...
Any chance we can see photos of your ugly glue-covered baby? 🙂
As you can see, I need to work on my build skills.
Would not pass at work.
Great thread.....I read it back and front on Sunday and amazed at the creativity from the OP. Bravo!
.......so while at work today I grabbed a strip of Coroplast and heated it with a heat gun. Coiled it up and then shaped to while it cooled. Wow!. Very easy to work, no kerf cutting required and it held its shape remarkably well. Not cheap as foam core, but IMO much faster to work and more rigid.
I'm well versed in polyester resins, fillers and cloth too. There will be some leftovers from my boat' enclosed transom project this spring so I'll mess around with that as well. Did make a B&W type mid enclosure stretching polyester over an MDF frame and brushed resin in it. Very nice, rigid and the stretching of the fabric made for really smooth and even curves. Stinks though.....and not exactly cheap,....at least the resin. Fabric is cheap. Lol
.......so while at work today I grabbed a strip of Coroplast and heated it with a heat gun. Coiled it up and then shaped to while it cooled. Wow!. Very easy to work, no kerf cutting required and it held its shape remarkably well. Not cheap as foam core, but IMO much faster to work and more rigid.
I'm well versed in polyester resins, fillers and cloth too. There will be some leftovers from my boat' enclosed transom project this spring so I'll mess around with that as well. Did make a B&W type mid enclosure stretching polyester over an MDF frame and brushed resin in it. Very nice, rigid and the stretching of the fabric made for really smooth and even curves. Stinks though.....and not exactly cheap,....at least the resin. Fabric is cheap. Lol
Thanks for the kind words Mayhem13. I'm looking forward to seeing your designs using the heated coroplast material that you describe. I am not familiar with coroplast. Can you post some pics?
Last edited:
Yes I see it now.
It looks hollow at the bottom, how low does the spiral coil go on your box? Kind of surreal to see my speaker in someone else's stereo shelf. 🙂
It looks hollow at the bottom, how low does the spiral coil go on your box? Kind of surreal to see my speaker in someone else's stereo shelf. 🙂
I think the spiral did not have quite the right shape. I made it freehand without drawing it, during a slow night at work between looking at work. (aerospace, which is why I'm a bit ashamed of that speaker's appearance. Would not pass muster here.) It sounds OK though.
What is the profile of that spiral supposed to be?
Log, involute, Archimedean, Euler, Hyperbolic, Lituus, Spiral of Theodorus, Golden, Fibonacci, or does it matter much? The spiral I made most closely resembles the last.
Spiral - Wikipedia, the free encyclopedia
Some links to coroplast panels:
Amazon --- http://www.amazon.com/White-Coropla...UTF8&qid=1390354682&sr=8-4&keywords=coroplast
U-line:
Corrugated Plastic Sheets in Stock - ULINE
What is the profile of that spiral supposed to be?
Log, involute, Archimedean, Euler, Hyperbolic, Lituus, Spiral of Theodorus, Golden, Fibonacci, or does it matter much? The spiral I made most closely resembles the last.
Spiral - Wikipedia, the free encyclopedia
Some links to coroplast panels:
Amazon --- http://www.amazon.com/White-Coropla...UTF8&qid=1390354682&sr=8-4&keywords=coroplast
U-line:
Corrugated Plastic Sheets in Stock - ULINE
Nautaloss II Plan
Ok, here is a sketch of the Nautaloss II plan. It is drawn to scale (each grid = 0.5 inch), but I would not be too worried if you are off a bit on the internal spiral dimensions as the point of the spiral is to absorb the back waves. If this was a horn with an open mouth then the dimensions would be more critical. The internal width is 5.0 inches. Be sure to add bracing every 90 deg at least for the first 1.75 revolutions from the mouth. I am including a photo of the internals again for convenience. Note that my spirals aren't that exact either.
Have fun.
Ok, here is a sketch of the Nautaloss II plan. It is drawn to scale (each grid = 0.5 inch), but I would not be too worried if you are off a bit on the internal spiral dimensions as the point of the spiral is to absorb the back waves. If this was a horn with an open mouth then the dimensions would be more critical. The internal width is 5.0 inches. Be sure to add bracing every 90 deg at least for the first 1.75 revolutions from the mouth. I am including a photo of the internals again for convenience. Note that my spirals aren't that exact either.
Have fun.
Attachments
Last edited:
X
A sub brings up another question, what are you using for X-over and DSP for room equalization. How are you measuring the speakers?
A sub brings up another question, what are you using for X-over and DSP for room equalization. How are you measuring the speakers?
At first I ran both full range and it sounded pretty good - it even measured pretty decently. Now I am using miniDSP 2x4 with advanced 2-way plugin for XO, EQ, & Delay. I use a Dayton UMM-6 microphone and the REW v5.1 (beta) software for measurement and EQ curve generation. I am bi-amping with a Yamaha RX360 (45 w/ch) amp for subs and a home built TPA3116D2 class D amp for the tops (40 w/ch). I am looking to get a couple of the prebuilt TPA3116's and put them in the same case as the miniDSP for a clean integrated look.
Pondering other variants of this to build, wondering if any make any sense.
a 4 Vifa high Naut horn,
A Naut with a spiral that twists as it gets smaller in the Z dimension, like a living Nautilus.(don't have the build skills to do this one myself)
With multiple boards layered above each other 3/16" with dividers arranged in a radial pattern to the edges of the board. with a series of decreasing diameter holes cut out from the center behind the speaker in a conical or bowl cutout shape. A radial smith horn.
a 4 Vifa high Naut horn,
A Naut with a spiral that twists as it gets smaller in the Z dimension, like a living Nautilus.(don't have the build skills to do this one myself)
With multiple boards layered above each other 3/16" with dividers arranged in a radial pattern to the edges of the board. with a series of decreasing diameter holes cut out from the center behind the speaker in a conical or bowl cutout shape. A radial smith horn.
Is the horn for the back wave or front wave? Any horn you put on the front of the Vifa will kill its nice flat response from 200 Hz to 18kHz.
If that mini DSP has delay, I may be able to put a huge sub in the corner of the room in an unused corner. The space is 12X20X80". I think I have a pair of 12" woofers from a pair of Pioneer speakers that got bashed up in too many moves. The cabinets are cracked. Sitting in a shed, so I do not know the condition of the speakers, may be OK or mouse eaten. Will have to pull them out, dissemble them and see. They used to sound pretty good.
The multiple board speaker would not be a front horn, would be back loaded. Did not make that clear. Saw something that Danely made with multiple parallel panels for back loading. Was never actually in production.
The minDSP has max 7 ms of delay which is not much. So you can't go too far away. I noticed that the iNuke 1000 Dsp has basically everything the minDSP does plus it has a huge amp and up to 300 ms of delay. You would need two of them and that would get pricey.
What about this guys DSP, has up to 1 second of delay shared for all functions including some of the filtering.
http://www.diyaudio.com/forums/digital-line-level/215379-dsp-xover-project-part-2-a.html
http://www.diyaudio.com/forums/digital-line-level/215379-dsp-xover-project-part-2-a.html
Cochle ear
Good thread and nice job OP.
After scanning a bit of the research on the cochlear spiral, it seems that it's ability to increase the sensitivity of the ear to low frequencies, is due to increased pressure on the outer wall of the spiral. The faster it tightens, and the more curvature there is, the greater the ray density against the wall. In this sense, In addition to keeping the radius as tight as possible, some damping treatment applied to the outer wall may improve performance. My .02c
Good thread and nice job OP.
After scanning a bit of the research on the cochlear spiral, it seems that it's ability to increase the sensitivity of the ear to low frequencies, is due to increased pressure on the outer wall of the spiral. The faster it tightens, and the more curvature there is, the greater the ray density against the wall. In this sense, In addition to keeping the radius as tight as possible, some damping treatment applied to the outer wall may improve performance. My .02c
Found something exciting, to use on the Naut spirals as well as other speakers, 5mm thick 4’X8’ mahogany door skins at Home Depot. (might be at other places as well) 11 bucks and some cents with tax. If you need it smaller to take home, the workers there will do a rough cut for you. .
For the Naut spirals, use the skins on all exposed surfaces. Has the advantage of if there is a glue spot, or other flaw, this can be sanded out and fixed. Glue spots and drips on internal surfaces does not matter, since it can not be seen there.
For the Naut spirals, use the skins on all exposed surfaces. Has the advantage of if there is a glue spot, or other flaw, this can be sanded out and fixed. Glue spots and drips on internal surfaces does not matter, since it can not be seen there.