Any way to model a woofer in an open tube?

[neRok]

Just wondering what it would do? I've got some old 6.5" woofers here and was mucking around with winISD to get a box design so that I could try them out as "cardioid" helpers with my bookshelfs. But then I just had the thought - what would the drivers do in an open tube? Kind of like the LXmini I guess. If the tube was long enough, would it have some sort of tuning effect? And what if it was progressively stuffed with filling, and/or tapered in diameter?

 

[digitalfrost]

An open tube is a rear- or frontloaded horn with a constant opening angle (0 ).

https://www.aj-systems.de (Paid)

or

http://www.hornresp.net (Free)


Any software that can model horns should be able to do it.

 

[neRok]

http://www.hornresp.net (Free)

I've heard of it. I guess I'll have to check it out.

Just whipped this one up for a chuckle. Get a 3m tube of 150mm PVC, cut it in half (1.5m each), woofer on one end, an adapter or a cap on the other end with a small tube attached (it could stick out, or stick in and lose a half a liter), and apparently that's a ported speaker? Lol

 

[Rednaxela]

Not uncommon in car audio.

 

[neRok]

This is all just a brain fart, but I was thinking about the "horn" aspect of it a bit more, because a horns driver projects down the tube/horn, and that's what you hear. I was originally considering the external sound to be the main sound, like a box speaker. Then I was thinking what would happen to the "back-wave" going down the tube. As in, would it be "tuned" by the tube? Could the "speaker" and tube-outlet be arranged in such a way in the room that the back-wave becomes in-phase with the main-wave? And my comment about the filling and/or tapering was alone the lines of the B&W Nautilus speaker, where it just "fades away". Anyway, lots to think about...

Like this crazy idea. 2 drivers sealed together, and then the "horn" side of things, maybe tuned, maybe not. It's kind of a 4th order bandpass if it's tuned? Anyway, the tube output can come out perfectly where required behind main speakers, thus possible to do "end-fire".

 

[Line Array]

by all means model it in hornresp

just to find out what a horrible idea it is

frankly it will be so bad you might never build a speaker again from PTSD

a tube is the literal definition of the opposite of what you want

modeling stuff in HornResp actually made me question whether i was qualified to design speakers because it showed me that physical reality doesn't quite reduce to the rules of thumb most DIYers use ...

with finite element analysis eventually DIYers will be able to know what the result of their project will be before building it just like how with 3D printing you can now do in hours what used to take ... longer

but i don't need FEA or HornResp to tell you that a tube will be the worst horror show you will ever hear

 

[sam_adams]

From:

Direct Radiator Loudspeaker Enclosures - Harry F. Olson, AES, Oct. 1950 (PDF)

 

[Line Array]

Not uncommon in car audio.

a lot of foolishness is common in car audio.

me and a friend once opened the door panel of his Nissan Maxima with Bose system to find out why it had the classical "no highs" sound Bose is famous for and there was a tweeter inside the door

it was literally inside the door - it wasn't up against the grille.

if an OEM would do this imagine what DIYers do in Car Audio.

in my experience PROSOUND ( and by that i mean PROSOUND not to be confused with PA ! ) is the ONLY area of audio where people have some semblance of a clue of what they're doing.

a typical prosound systems costs about $2 million versus about $20,000 for a typical PA system and $2,000 for a typical hi-fi system.

only prosound systems are designed by people with physics PHDs - everybody else just throws stuff together and hopes it will work.

Studio Monitors are in 2nd place after Prosound for the average IQ of people designing them.

DIY Car Audio is at the very bottom of the food chain consisting mainly of illiterate 20 year olds.

 

[neRok]

but i don't need FEA or HornResp to tell you that a tube will be the worst horror show you will ever hear

My original post was asking about the internal side of a ported enclosure, not the external/output side where it would be a horn. Perhaps this graphic will do a better at asking my question...



If the 3 boxes on the left all have the same driver, volume, and port tuning, then I would think they would perform similarly. But what does that mean with regards to the bottom-right example?

Perhaps there is some rule (ie. more to the science) like "ports can only be up to 50% of a enclosures face" or something like that, which means that isn't a port.

Edit: Perhaps the "ported round-box" is both a 150cm box with 50cm port, and a 50cm box with 150cm port, and everything in between, all at once? So maybe that is a 0-degree horn? lol.

 

[Jim Taylor]

This link, from John Kreskovsky's Music and Design website, might help you. I hope you find it instructive.

NaO U-frame