VIB 170AL mit Impedanz = 4 OHM?

[YouGo]

Hi there

Is it possible to change the crossover of the VIB170AL, so that the nominal impedance becomes 4 of 6 Ohms?
I want that, because my amplifier has only 50Watts @ 8 Ohms and 100W @ 4 Ohms.

YouGo

PS. I have also placed this topic in Forum Elektronik but I think it is better to place it here

[derjan]

That woundn't make ANY sense. The drivers still have 8 Ohms.

You surely could build something to get a 4 Ohms Vib170AL, but the only thing you'd be doing is burning the additional 50 Watts in some kind of resistor.

You would waste more energy, the amp is getting hotter, but the speakers won't play louder.

[YouGo]

Hmmkey...
So that wasn't a very smart question.

[derjan]

A much better idea would be to build Vib170AL with two AL170 per box!

Such a project has already been built by antoher user...

http://www.visaton.de/vb/showthread....highlight=dual

[YouGo]

I see that box has a much higher efficiency (if the graph has been made with 1 Watt). Is that only because the box has more speakers, or does it also have something to do with the crossover design?

[4real]

The efficiency of my DuAL is a bit better, and the minimal impendace is quite low (3,8 Ohms).

But note that not all amps will like this (even if the specs say it will deliver more power @ lower impedance). My Marants SR-5200 can handle it, but I'm sure it's on the edge. Next monday, I can use my brand new (eh.. not excactly new, but still) Parasound HCA-1000A, which will do 2x 200 @ 4 Ohms. That should work very nice.

You could of cource find some circuit to lower your impedance, and your amp would probably give 100W, but the circuit itself would most likely burn the extra 50W itself, leaving just 50W for the speaker. Not to mention what the circuit would do for the bass response (BR tuning would probably be way off)!

[Frankynstone]

You can reduce the impedance by transforming ist

Search in some tube amplifier forums for someone to make an audio transformer for your speakers with a ratio of 1 : 1.4 or 1 : 1.5 and don't forget to tell him the speaker impedance of 8 ohms and the sinus power (same as RMS) of 100 watts and you can chose a reasonable lowest frequency to be passed, e. g. 30 Hz.

How it works: drive the speakers at the 1.4fold voltage, the 1.4fold current will flow and 1.4 times 1.4 makes 2 --> twice the power. Your amplifier "sees" half the impedance.

Result: The sound comes a bit louder, of cause. But depending on the quality of the transformer there could be a loss of highest frequencies. Ask the trafo maker about the aplicated winding technology.

much success

[broesel]

Die Differenz zwischen 50 und 100 Watt sind man gerade 3dB mehr Dreh am Lautstärkeregler. Mann sollte sich fragen: Ist dieser minimale Lautstärkezuwachs es wert, irgendwelche Verrenkungen bei der Konstruktion der Box zu machen?

[Frankynstone]

If I were you, I would not try to change anything. Twice the power is ridiculous. Broesel is right, 3 db is nearly nothing. Yeah, one can hear the difference, but it's not much. Do double the volume approx the tenfold power is needed.

Dear YouGo, if you like to, then build another kind of box with high efficiency speakers and it will be loud but im sure, that an 8 ohm box runs fine at a 4 ohm amp.

so long