RWA Voigt pipe measurements!

The measurements of my Voigt pipe, so you can build them if you'd like to.
It's a perfect match for:
Fostex 8in drivers (FE204, FE206, FE208sigma)
Cube Audio Fc8
WE 755 series
& quite likely a very good match for most 8in full range drivers
Made with pine. I VERY, VERY highly recommend to build from higher grade pine or spruce if you can source it.

[@hoobsgroove]

might be worth trying a ¼" board on the top side port, sticking out an inch and a half and 3"sticking in, can attach it with a bead of blu tack, should increase the bass rohloff +2-3db and prevent the cancellation so easily from the driver, somewhere between -40Hz to -120 Hz depending on driver. don't forget checking your opening port measurement you have to take in consideration the three quarters of an inch that is part of the opening port. worth painting the boards with an thin epoxy resin that will help with lower frequencies totally sound better more like using old type of wood, help with the knots as well

[@realworldaudio]

👍 I tried that, actually several different sizes, and they were largely ineffective or offered less advantages than placing a slanted LP cover in front of the port/slot. However, placing a thin blue tac strip (approx 1/8in diameter) was a noticeable improvement: placing both outside and inside.... however, the cats ate it! When you see them sniffing the port on the videos, they are looking for leftovers of the blue-tac... The low bass performance is actually astonishing, shames badly most subwoofer / main speaker combos in the high end range.

[@hoobsgroove]

@@realworldaudio 😂

[@IDontExist14]

Thanks for the design

[@realworldaudio]

🎶👍

[@andredebacco]

hi janos! I was waiting for this video! I will make two voight pipe for FE206NV. But shouldn't the mouth area be similar to the cone area? from the photo it seems to be bigger... Thanks, Andre

[@realworldaudio]

I know, I made it bigger than most pipes. I followed Derek Walton's mouth area recommendation, and it worked superbly. I'm getting much deeper bass than people get with Voigt pipes in general, the larger mouth might be responsible for that. I tried several pipes with smaller mouths (different drivers, many different parameters though), and this cabinet VS others are in such a different ballpark. (Like Bruce Lee vs the novice kid... that different to my ears.)

[@andredebacco]

@@realworldaudio thanks Janos!

[@danbuffington75]

The placement of the side boards seems to be traditionally be on the outside of the other boards. Does it really matter, acoustically?

[@realworldaudio]

👍✨ On the sides it offers more stability - on he inside the top would be just a sliver, that breaks easily, not good to work with. I have see one pipe with the side on the inside, it can be done, but on the outside works better both for construction ease and resonance control.

[@danbuffington75]

@@realworldaudio and tradition...

[@danbuffington75]

@@realworldaudio thank you for explaining. I can see how it would be more stable.

[@luminousfractal420]

Many socks 😐 But I tested the sock fairy. I put 4 items into the machine including two socks. Only one sock came out. The sock fairys are real. The cats are sneaky smart but they can't steal a sock from an active machine😂

[@wjcze]

so I wonder if the VAS of the loudspeaker has any significance in the design of the Voigta loudspeaker? Because when you mention, for example, Foster speakers that fit your enclosure, their VAS ranges from 35 to 71L. Really, where did these curves in your pipe come from? -They depend on the room and not on the speaker at all?

[@1christian1sonne1]

Very nice

[@realworldaudio]

Thank you Christian! ;

[@adrianneukirchner]

Hey Janos, thanks for your Video... Is there a recommendation for the width of a Voigt Pipe. I'm designing one on my own at the moment. I understood that in order for the angle you have to calculate it proportionally to the volume. But what is the volume if you haven't determined the width of the speaker. Thank you in advance.

[@realworldaudio]

The width should be as close as possible to the drivers size, but going narrower than 20cm will result in nasal thin sound. I'd say aim for 20cm width, and go larger if the driver does not fit, but try to avoid narrower.

[@stevenjackson8226]

Thanks for all this. I see below a reply to a question about stuffing/damping. I suspect this is bit like stuffing in a ported enclosure. You certainly don't want to cover the port. How about flush mounting the driver? Every speaker measurement I recall seeing typically shows up some refraction around a raised driver, and none/less with flush mounted drivers. Have you ever measured a set of Voight pipes/TWQTs?

[@christophgraf63]

Hi Janos. Do you think it would be worth to try this design as folded voight pipe ? My room would be ok I think with 7mX8m. I got the principle from a previous video of yours. What I still do not get is how you calculate the total length of the folded design as the inside "seperator" goes around to the middle of the driver... ?????? thanks for all your great videos 🙂

[@realworldaudio]

The quarter wave length of a folded pipe is practically the double of the internal height. Folded pipe in comparison to the straight pipe muddies the midrange, and imparts a noticeable cabinet coloration to it. The straight pipe is much superior. The folded pipe does not have sonic advantage - it looks visually more like a typical loudspeaker, but it's a noticeable step back in sound quality. This straight pipe (I have designed /built) two of it, stands a class above all folded pipes I tried / heard.

[@Thelonius.M]

Hi!! Thank you for sharing the design..what about internal filling?is it necessary?what material do you use in this design and where you put it??because i saw some in one of your videos with this voigt pipe.thanks

[@realworldaudio]

Loose polyfill to the top only, and a little felt on the back panel behind the driver.

[@Thelonius.M]

Thanks a lot 👍

[@heshoh2]

Hi Janos. You mentioned that the top of the Pipes are glued together. I noticed that you used brass screws to attach the boards but is glue used there also? How far apart are most of the screws? Is there a special type of glue that you used or just a good glue like Elmers glue? Thank you.

[@nicktube3904]

Just normal wood glue D4 will be fine. It’s extremely strong it will not break at the glue part but the wood around would break

[@miroslavnovotny5025]

Hello Janos, is there any calculation for the port size? i didn't find any recomendation. am i correct the length of the room shall be like 4 meters? for 1/2 wave length? is that ok for (i don't remember) about 50-60Hz?

[@realworldaudio]

Hello Miroslav, indeed, I don't think there is a general consensus about the port size. Having the same surface area for the port as the driver surface area is a good start. Keep it that size (or even little smaller if you have problem with not enough bass in the room) for smaller rooms, and can increase port size for larger rooms. The 4 meters will get you about 43Hz or so for the half-wave. Cheers, Janos

[@asadabbasmirza9519]

When and which material to stuff with.explainn please anything at back of driver??

[@asadabbasmirza9519]

4" drivers? Jordan.

[@m.j.s.3838]

Would your cabinet dimensions work with the Cube F10 Select in a 24 by 19 by 8 foot room? My drivers will be here soon…

[@realworldaudio]

That's quite similar to my room, it's a perfect match!! ;)

[@menachemsteinberger8505]

Many thanks for this great video. What drivers do you use?

[@realworldaudio]

Cube Audio Fc8

[@makcheeseng1284]

Hi, is it possible to build a voigt pipe for a room less than 6 meters? Tq

[@asadabbasmirza9519]

What to stuff and when to stuff ,glass fiber....??????

[@asadabbasmirza9519]

Will red oak do? Though more expensive?

[@asadabbasmirza9519]

By cutting top ,it will tame lowther high frequency sensitivity?

[@realworldaudio]

Sadly no, because that comes from the whizzer cone. Placing a second cone between whizzer and main cone will help with the issue, but you need a contraption to secure the cone to the cabinet. It should not touch any part of the driver, you can try something as simple as a cut out coffee cup. Looks ugly but works miracles.

[@asadabbasmirza9519]

Can one seal the wood from inside with a coating of wood sealer or wood barrier to withstand moisture movement? Any difference in characteristics of wood for accoutic reasons?

[@ufarkingicehole]

Would a bigger driver be better assuming you scaled the cabinet?

[@realworldaudio]

You will get capacity for louder playback levels, greater dynamics, stronger midbass... but speed, top extension will suffer. So, not an easy, nor a straightforward choice ; ). Overall, to me, certain music will sound better on the bigger one, while others on the smaller one....

[@TitofBee]

variable thickness along the width, like a cello... (?)

[@realworldaudio]

Yes, that would be the goal! It's already high time to re-finish my Voigt pipes (the cabs are already 22 years old!), will do that with varying the cab thickness ;

[@TitofBee]

can't wait to see that. hard to find nice spruce of this size

[@adfgyahoocom]

Thanks for the design!! I have some questions for you) I checked the design of cube audio for Fc8 it seems you have the same geometry but not truncated. What does it improve? 2In order to adapt the design for 3 in drive (may be 2 drivers) the main parameters are the height and the base angle (as the volume can be reduced with filling material) 3) Why do you prefer pine or spruce over the plywood?

[@realworldaudio]

Hi Anton, truncating the pipe is fist of all cosmetic - people are far more willing to put a 1.4m tall speaker in their room than one that's taller than you. Soundwise, the truncated version accentuates midbass, and the full version allows a lot lower bass extension. So, for a 3in driver/ pair of them, 1.35m height for a pipe is perfect. The Fc8 loves the 1.9m height and can utilize it to go down to 25Hz with authority. Technically, the 3in driver also goes down to 25Hz in the same cabinet - however, the small driver is not capable of the large excursion that the 25Hz would demand, so can reproduce it only at very low volume.... yet, it's a lot of fun, hearing tiny drivers go down real deep, can freak people out. I do not recommend reducing the volume by increasing filling. Filling KILLS, violates the sound. Use as little as possible, otherwise it will become a lifeless mess, exactly like a mediocre commercial loudspeaker. I prefer spruce and pine because they have life and personality, although high quality plywood can get close, but not there yet. I have a series on wood types for cabinet material where I go deep into the physics of resonance transmission - spruce is the best, and plywood mimics a low grade spruce.

[@TitofBee]

@@realworldaudio in a cello or a violin, spruce transmits waves very strongly along the fibers and is less strong in the width of the mainboards. this offers a unique coloration. by its mechanical characteriics in each directions, plywood can't offer the same vi(fi)bration transmission. even with a thickness distribution in width. next step could be to CNC-mill the main boards from spruce. even 2 layers especially handsanded for a lower cost could work. 2 small midranges with the same global Vas could be a more affordable operation. i'm also thinking about a linkwith tranformation, with a sprectral analyse, corrected by DSP , Janos what have you tried on this point? it make miracles on a sealed enclosure and a single midrange driver to deep in bass to the max.... sorry for the long message

[@m.j.s.3838]

Magico looks like my cat, Sasquatch, r.i.p. He loved to sleep on my socks, not steal them.

[@realworldaudio]

So sad Sasquatch is gone! :(

[@asadabbasmirza9519]

Curve at lower bottom at back???

[@asadabbasmirza9519]

Any change for lowther DX3?

[@dannixon247]

👏👏👌

[@realworldaudio]

Thanks Dan! ;

[@asadabbasmirza9519]

What bout that guy making voight with plywood and one layer after application of polyurethane damper in between.

[@asadabbasmirza9519]

Sorry DX 4 ?

[@asadabbasmirza9519]

Immediately plan is underway for vintage coral 10 inchfull range ,brand new ...

[@asadabbasmirza9519]

Is that a kit amp at the back? Darling?

[@dannyalvens5418]

A darling amp doesn't use 807 tubes....