Vifa TML

[kyote]

Hello,
i had planned to build a TML with the following Speakers:
- 2x Vifa TC14-SG49-04
- 1x Monacor DT25N

Now you have to know am still a Newbie and my trys with Martin King's Sheets hasen't been very successful.

Because of that I want to ask you to help me out with the TML design.
The Parameters of the woofer are:

Nominal impedance [ohm] 4
Voice coil resistance [ohm] 3.1
Fs [Hz] 52
Voice coil inductance [mH] 0.45
Eff. diaphragm Area [cm²] 80
Moving mass [g] 8.1
Force factor [Bl] 4.3
VAS [l] 10.5
Qms 2.79
Qes 0.44
Qts 0.38

I want to use two of them for each speaker.
I would be thankful if you would help me.

Greetings, Olli

[BillFitzmaurice]

You may want to reconsider these drivers for a TL. TLs are generally used as full range speakers, and with their 52 Hz Fs you probably won't get response much below 60 Hz with these, which means you'll still need a sub. For what they're capable of these might be better suited to a sealed box. Drivers with similar specs but with fs 20 Hz lower would be a different story. Look at the Thor kit at the Madisound site.

[kyote]

Thank you for your suggestions, but the Compny Newtronics use similat woofers for a TML and I want to build something like that.

Surely they won't give me the Plans for their Speakers so I asked here to help me Design them.

P.S.: I already have the Speakers. Got them cheap.

[cheesehead]

I made a MLTL with the Vifa TC18's, the TC14's big brother... they require a huge box. As with the previous post, I'd go with another driver.

*EDIT* - of course if you already have them...

[BillFitzmaurice]

Compny Newtronics use similat woofers for a TML and I want to build something like that

I don't speak German, so I can't comment on the speakers you're referring to, but it's safe to say that if they're using these drivers then they still need a sub. From the standpoint of both size and complexity a TL is still not the best way to utilize the drivers you have on hand, especially if you are a newcomer.

[kyote]

Hmm,
and what would you recommend instead?

On the Newtronics Page they write that their box (Skate MK III) has a lower Frequency Stop at 40 Hz at -1dB.
Sounds good to me. Don't want more.
To the Newtronics Skate MK III


P.S.: I've already build another TML Casing. It's a speakerdesign from the German Mag Klang+Ton and can be found as CT206.

[GM]

Greets!

I only made a cursory attempt to match their performance with the your driver's published specs and couldn't, so I have to wonder if either they are off quite a bit or Newtronics tweaks them to suit.

Anyway, adding 1.0 ohm of series resistance raises Qts enough that in a straight ML-TL that's a bit larger than the Skate, ~flat to 40Hz is doable after some baffle step compensation (BSC) is used. The added resistance also allows the 4 ohm drivers to be wired in parallel without overdriving your amp if it's rated for a 4 ohm load.

In this alignment they are Xmax limited to ~10W, but since you have four, very low distortion 100+dB peaks down into the high 30s is theoretically available even with BSC so with a bit of room gain, they should play loud enough for most folks.

Plug these into MJK's ported box WS for a sim:

Fs = 52 Hz
Re = 2.55 ohm
Lvc = 0.225 mH
BL = 4.3126 n/a
Sd = 160 cm^2
Vd = 21 L
Qed = 0.724
Qms = 2.79

L = 52.3"
zdriver = 18.5" - this would be the midpoint between the two
zport = 50.6"
density = 0.2 lbs/ft^3 as a starting point
S0 = 75"^2
SL = 75"^2
rport = 1.5"
Lport = 0.75"

If nothing else, it is a good performing alignment for you use as a baseline to experiment with.

FWIW, I recommend putting the two woofers right up against each other and make the baffle wide enough to put the tweeter in the 'v' between them, so mirror image baffles will be required. Better still, make them bipoles.

GM