TQWT with 2 drivers - what to look out for?

[Rudolf]

I want to do a ML-TQWT with two 3" drivers in a MTM alignment. Line length will be 16". The distance between the 3" drivers is ~ 5". So its no "point source" anymore. Would a simulation with Martin Kings worksheets still give meaningful results?

How about the input values for the worksheet? Since the 3" are wired in parallel, I have to double Sd and Vad and halve Re. But I am not shure about Lvc, BxL and the Q-factors.

Thanks for some suggestions

Rudolf

[Timn8ter]

Martin addressed this in an article on his web site.
Two drivers in TQWT
You have the basics correct.

[Rudolf]

Thanks Timn8ter,
should have looked at MJKs site in the first place. Seems I´m getting too lazy.

But I am still not shure, if the distance between the drivers in such a short line could be an issue.
Anyway, I`ll get some ply tomorrow and give it a try

Rudolf

[Timn8ter]

The distance between the 3" drivers is ~ 5". So its no "point source" anymore.

I figured it would come up later. Is the 5" distance center to center? Why would you not make them 4" apart? Have you considered a bipole configuration?

[Rudolf]

Sorry, the drivers are only 2" and the distance is 5" center to center.

It´s a fixed system - an acoustically sound implementation of d´Appolitos theories. You see it in my first post. Obviously it´s only useable up from 100~200 Hz.

More details are here:
http://www.speakertrade.com/site/pro...roduct=Mmhe280

[Timn8ter]

Ah, I see. That's interesting. Part of the ML-TQWT theory is to place the driver at the point of the 3rd harmonic. I'm wondering if you use the center point between the two drivers for that.

[Rudolf]

That is exactly what I will do. I look at the system as a "very narrow" 8" woofer with the tweeter in the center. The weekend will show,whether this is right.
Thanx for your help.

Rudolf

(You´ve got a very attractive hometown. Been there - loved it!)

[weidok]

Hi Rudolf
Are you going to use teh MHE 280 MK II "Mittelhochtoneinheit " in your ML TQWT with the Gradient ??

[Rudolf]

Are you going to use the MHE 280 in your ML TQWT with the Gradient?

The MHE 280 is doing nicely down to near 100 Hz. So it would be a waste (of both speakers) to combine them with the Gradients.
I will put the Mivocs on top of small dipole subwoofers. It´s the most far out combination I could imagine for a small room - so I had to do it.

It will look somewhat like this (yes, it´s still another ML-TQWT - with a Fostex FF 85K):

Regards
Rudolf