Zigmahornets on their way..

[Scottmoose]

The quick and easy method. On reason why you couldn't, especially as the FE103E is never going to generate massive internal SPL, so vibration shouldn't be too bad. Damp the cavity with whatever you have to hand, and you should be fine.

 

[Sylver300B]

Re: Sloped Top Issues

I assume you could eliminate the sloped top by "boxing out" that portion of the speaker and adding an internal sloped piece? Right?

Just thinking in terms of speed of construction, or WAF for someone whose wife (like mine) asked if we had to have that slope on the top!

travis

Hi Travis,

For my first project, I sure did add a few complex tricks.. And at each step, I had to figure out "how" to do it. The sloped tops are done right. As well, I added a interchangeable faceplate, so that I can try different drivers, of different sizes, without altering the cabinet afterward.. and I thought of making different face plates to match these drivers... and adding a hole at the back (covered with a plate) so that I can add a second driver at the back to make it dipole.. and I .. anyway, I'll soon put pics of it.. Let's just hope they're fun to listen to.

How do you like your own Zigmas?

 

[planet10]

Re: Re: Sloped Top Issues

so that I can add a second driver at the back to make it dipole

Bipole not dipole

dave

 

[Scottmoose]

You'd need to double the effective size of these if you're going to use two drivers in biole (or any) configuration as I understand it. I could be wrong though, and it will be interesting to see what gives at any rate. Not a bad idea though -I'll have to give it a try at some point. Good luck!
Best
Scott.

 

[planet10]

You'd need to double the effective size of these

Normally it would be the case (double the cross-section. But with the variety of drivers he is trying, would be worthwhile to try.

dave

 

[Scottmoose]

True. I was forgetting that. The results will be interesting at any rate. I'm trying to model the Zigma in MathCad without much success at the moment -mostly because I can't for the life of me work out exactly what sort of speaker it is! Any thoughts? TL, BR?

Best
Scott

 

[planet10]

Originally posted by Scottmoose mostly because I can't for the life of me work out exactly what sort of speaker it is! Any thoughts? TL, BR?

It is an ML-TL... best modeled in the sections worksheet -- then you can model the angle at the top & the port without any figuring.

dave

 

[Scottmoose]

Cheers Dave, that seemed like the best option, but I thought I'd check to make sure!
Scott

 

[Sylver300B]

theory

Well, I am just a beginer, and alas, have not much theory.. Just trying so see what makes what, and then try to explain it.

So, I made my enclosures so that I can put the Fosters in it, then try the Philips, and as well, put back the Fosters but in "bipole" configuration.

I'm almost there, just need to fnish some details, and I'm ready to go.

 

[Scottmoose]

I look forward to hearing your oppinions on the different combinations -it sounds an interesting project!
Scott

 

[Sylver300B]

It is an ML-TL... best modeled in the sections worksheet -- then you can model the angle at the top & the port without any figuring.

dave

Hi Dave,

What is an "ML TL"?? 😕

I guess TL is for transmission line, but what about the ML?

 

[tleonard]

ML = ?

ML = Mass Loaded, although I'll leave it up to someone more qualified to explain what that means...

If all goes well with my garage sale tomorrow I'll have the cash and working space to begin construction on several projects, including some zigmas...

travis

 

[Sylver300B]

Re: ML = ?

If all goes well with my garage sale tomorrow I'll have the cash and working space to begin construction on several projects, including some zigmas...

travis

We should start a Zigma club.. he he..

That's fun and very motivating to have friends you all, building similar or related projects.

May I can add in my CV "Zigma builder" ? 😀

OK, I did not graduate yet.. but one day.. 😉

Oh, and... what "mass loaded" means?

 

[Scottmoose]

What is Mass-Loading? Oh dear, a technical question! Read this (and the rest of Martin's site):
http://www.quarter-wave.com/Project02/ML_TQWT.pdf
All will be revealed. Probably. If you can wade through the math -Martin is very obviously a latant mathematical genius. Still, that's what it took to crack the mysteries of the TL. You can still build this superb project BTW using the FE167E. I've built two pairs so far, and may build a third quite soon.

Short version: in practical terms mass-loading involves stuffing strategies, or lining the cabinet, as Bob Brines generally does now with his designs. This added mass loads the quarter-wavelength standing waves generated in a transmission lines' cabinet. Also, with straight ML TL and ML TQWT designs, a port of some form is usually employed: this adds additional air mass to the loading on the quarter-waves thanks to the restriction provided by the port.
Best
Scott

 

[Sylver300B]

What is Mass-Loading? Oh dear, a technical question! Read this (and the rest of Martin's site):

Short version: in practical terms mass-loading involves stuffing strategies, or lining the cabinet
Best
Scott

Is the Zigmahornet a TQWT? or a TL? or just some kind of tuned pipe? and then, should it be "mass loaded" furthermore by adding stuffing?

By the way, I started reading the doc you refered to, and it's quite interesting. It's sunny and hot here (at last) so, reading will have to wait a bit, but I'll be back to it soon..

 

[Scottmoose]

Glad you've found the documentation useful.
As for the Zigma, I had trouble deciding what it is myself, so you're not alone! My guess, confirmed by Dave, is that it's a straight, mass-loaded design. The mass loading in the case of the Zigma in my experience only requires a 1in layer of felt etc attached to the sloped top. The models I've run recently suggest, this slope actually doesn't make a huge difference to the sound.
Best (& enjoy the sun!)
Scott

 

[planet10]

Is the Zigmahornet a TQWT? or a TL? or just some kind of tuned pipe?

With King & Augspurger allowing us to explore much more of quarter-wave space, the pigieon holes we have used are starting to become blurred. A TQWT (aka TQWP, Voigt Pipe) is a QW design that is larger at the terminus end than at the closed end and has linear taper. A TL is smaller (or the same) at the terminus & larger at the closed end. But to make things a bit trickier the whole space can be referred to at times as pipes, or TLs.

and then, should it be "mass loaded" furthermore by adding stuffing?

The Zigmahornet is an ML-TL. It is the restricted terminus (aks port) that provides the mass loading. As well as providing mass it also adds a pole to the high frequency output of the terminus, meaning that less stuffing can be used to kill the undesired line harmonics, typically resulting in more LF gain at the terminus.

Stuffing has nothing to do with mass-loading, its purpose is to provide a LP function at the terminus

dave

 

[Scottmoose]

I tend to view mass-loading as the air in the cabinet in general, with the restricted area of a port providing an additional load. Stuffing / lining damps higher harmonics in the mass-loaded line, which 9 times out of 10 this technique requires to smooth out the frequency response. My description before didn't make that clear (I really should have woken up before writing!)

Cheers
Scott

 

[Sylver300B]

Stuffing has nothing to do with mass-loading, its purpose is to provide a LP function at the terminus

dave

Hi Dave,

and what is the "LP function" you are refering to?

 

[planet10]

and what is the "LP function" you are refering to?

LP = low pass... in any "TL" the goal is that the terminus only passes frequencies around the fundemental resonance and that all the higher resonance modes are filtered out. You do this with geometry and stuffing.


dave