Another Voigt Pipe

[xrk971]

So is IkEA pillow stuffing the best? Have you tried polyester microfiber cloth like used for cleaning glass surfaces? It has lots of surface to volume ratio.

 

[pianolydia]

Yes, even Visaton mentions a Vented optimised 4.4Cu.ft 35Hz.

I will comment here since I started this design. It was never going to be a subwoofer or low as an extended woofer design. This is strictly for midrange and single ended tube Faire. So yes, a helper subwoofer would benefit! But, I could make it full 72" like the original Pipe and then it will give us better results, closer to a low woofer would go. I modeled this in BassBox pro 6 and had 40.65 liters at fb 40.85 and a f3 at 66.87 and with one 3" x 4-3/4" long port at 3-4 watts would be plenty in a small to medium room (tube watts) Spl on that driver is 92-93 So I would presume nothing too loud! But, let's not say that this can't go to 35hz. Just have to be ready for output vs CD bottoming out and can damage the driver. Better to make this design the full 72" height and be done with it! Pianolydia
P.s. Though I would have to give up my left over wood wouldn't I....

 

[kees52]

Hi Bjorno

I go here because the hornresp thread is not for this kind of bussiness.

YOu say the numbers are different, yes I play with them only the old numbers who belong to the pipe but have now re-measure them and put in hornresp, this give a need of some more damping (375 grams) and some in beginning of S2. Last picture give some bump on the end, this dissapairs when use proper crossover (frq and order) more damping destroy low end, (this is hornresp advise afcourse).

I use fiber whool like on the rats nest;-).

this pictures is of how it is now. I go do also a measurement in real.

 

[larryldspkr]

I really like the look of the voigt pipe, 6ft makes good sense and puts the driver at the right height! Better bass with more volume sounds like a better build, save your wood for a different project. Go for it!

Larry

 

[GM]

I've spending most of my 'Retirement' time(Since last Summer) in an Acoustics Laboratory at:

Sontech International AB

Regarding my own interest:
I'm focusing on finding Materials with low Flow Resistance at Low Volume Velocities (RMS= max 10 m/s)+Low Absorption Coefficients trying to find good Damping Method Metrics....

Greets!

Cool! I’m ‘green’ with envy!

Sounds like a great [and challenging] project of contradicting goals that should keep you busy for awhile. Looking forward to any insight you may share with us and thanks for your continuing efforts to ‘peel back the veil of science’ [as Tom Danley calls it] for us math challenged DIYers. 😉

GM

 

[GM]

this pictures is of how it is now.

FWIW, HR's 0.5 pi space corner loading is unrealistically optimistic in all but the largest, most rigid, massive constructed rooms, so using 1.0 pi for corner loading is recommended and if you have a 'floating' floor, stick built, hardboard or similar sided house like I do, then best overall to use 2.0 pi to ensure an acoustically adequate speaker alignment.

GM

 

[Greebster]

Greets!

Cool! I’m ‘green’ with envy!

Sounds like a great [and challenging] project of contradicting goals that should keep you busy for awhile. Looking forward to any insight you may share with us and thanks for your continuing efforts to ‘peel back the veil of science’ [as Tom Danley calls it] for us math challenged DIYers. 😉

GM

Like in florescent! 😀

bjorno,
Noted the Ikea stuffing. Wife won't be pleased I killed my pillow, but Ikea is just an hour up the road. At least I waited til morning 😉

Also ask if you have tested any microfiber materials. Have various wash cloths, hand towels and full sized towels. Also a microfiber "muppet" washing mit, for good measure.

 

[GM]

Micro fiber towels, etc., aren't very transparent, though lining walls, including vents, horns with the cheap ones I buy in bulk at Samsclub work well for fine tuning. Haven't seen a washing mitt with such long fibers, but my first thought is to use them to damp/diffuse driver frames, motors. Adding a piece of one to a 'screeching' wide BW driver's dust cap might be both visually and sonically entertaining. 😉

GM

 

[Greebster]

Micro fiber towels, etc., aren't very transparent, though lining walls, including vents, horns with the cheap ones I buy in bulk at Samsclub work well for fine tuning. Haven't seen a washing mitt with such long fibers, but my first thought is to use them to damp/diffuse driver frames, motors. Adding a piece of one to a 'screeching' wide BW driver's dust cap might be both visually and sonically entertaining. 😉

GM

That was my assesment of the towels, to line the walls, tho draping down the length of a line works quite well to maximize flow. Wasn't an issue with the MLTL I'm working on. Originally had a 30cm² 3.8:1 slot port, 3.25 (8.25cm) long. Chuffed horribly bad around 30Hz down with a high third harmonic resonance to it. Fixed the harmonic issue with clay lol But went on to change the port anywho. Used a 2.5" ID electrical pvc pipe, accommodated for the area change by increasing length to 3.75" for the same tuning. AMAZING amount of output from the port measured nearfield is only -4db +1 down from 20-40 Hz driver level measured under the same conditions.

Did some sealing of the enclosure overnight, slight leak between short leg end and the longer leg. Nothing major, had to listen close up to detect, unlike my drywall ceiling, which is having a fit above 105dB around 65Hz. Touchaire lamp at 186Hz etc. Am thinking, this is only one and each speaker will have two and I have 8 for this purpose 😱

They were cheap, couldn't help myself and bought a dozen total 😉

Glue just dried and have a couple hours before the wife gets home. My son is loving it, the neighbors that're home don't 😀

Back to stuffing tests... Like the kids that have their own toboggan track up in Minnesota... Weeeeeeeeee

it's 70f here atm, school must be out because unsupervised teeny girls are at the pool. Most don't get out, parents and kids alike, until lightning blows up a power transformer in the Lightning Capitol of the US. Sorry had to vent 🙂

 

[Greebster]

forgot to add the graphic 🙄

 

[tca]

Hi,
Have a look at these Pictures:
b🙂

I've tried to simulate the same but I get something completely different!

What am I doing wrong?

Thanks.

 

[kees52]

Bjorno

I have did a measurement with Room Wizzard.

I have some room problems but I think this graph is not bad at all.

The same damping, the same box input some posts ago.

I did see that the mic input of the pc is not very good, I am building now a high quality
mic amplifier with OP opamps.

I have the T-TQWT with two open baffles with old phillips speakers and a tweeter filters are 6 dB for open baffle, 12 dB for tweeter and 24dB for woofer.

Only when I put the subwoofer out of phase it works oke, I do not now why this do happen, I did see the 24dB filter do this to him. Measurement is in middle of the room, sub in a corner facing the long end of room.

Second photo is only sub on differend places, you see how tricky it is but you now that afcourse better then me. thirth photo is only the open baffle and the last photo is when baffle correction cicuit is on.


regards

kees

 

[David McBean]

I've tried to simulate the same but I get something completely different! What am I doing wrong?

Hi tca,

1. Select Tools > Combined Response from the SPL Response window to get the result shown in the attachment below.

2. You need to use the Loudspeaker and Filter Wizards if you wish to generate results similar to those shown by 'bjorno' in post #12. See the Loudspeaker Wizard and Filter Wizard sections in the Hornresp Help file for further details.

Kind regards,

David

 

[tca]

^ Got it. Thanks.