In Search of MidRange Replacement-

[Cu-Melter]

Good Morning All-
I'm trying to find a suitable replacement driver for a pair of Realistic Mach Two cabinets.
5" Ferro-Fluid...If I knew the crossover points, that would help me in my purchasing decisions.

If someone could help me determine the crossover points within this circuit...?

http://www.frontiernet.net/~dreagh/Shack/MachTwo_Schem.gif

My main curiosity is if someone could post up the cross-over points of the Mach Two.
Anyone have a spec sheet on hand?
Large A$$ Thanks in Advance-

[Cu-Melter]

Come On- Where are the ivory towers around here?

[Luvin Da Blues]

I'm at work and don't have time to fool around with it but here is a calculator for you to use.....

http://www.carstereo.com/help/Articles.cfm?id=1

[cjpremierfour]

The Radio Shack support site gives the 400-4032 and 400-4032/A Mach 2 mid-range crossover frequency at 800hz to 6000hz. The woofer's range is 25 to 800hz and the tweeter only has a top end extension spec of 40k.
** The site does not give a crossover slope on any of it's drivers.

[harley .guy07]

once you find out the specs of the driver you want. try out madisound or Parts express. they both have plenty of drivers in that size that are of good quality and you can probably find something that would work for you.

[Cu-Melter]

The only midrange drivers I've located are 8 ohm.
Could I place a resistor shunt across the speaker terminals to compensate for this?

My math concludes 24-25 ohms resistor..
or should I consider changing the seried lamp fuse #2 .........

[Cu-Melter]

The Radio Shack support site gives the 400-4032 and 400-4032/A Mach 2 mid-range crossover frequency at 800hz to 6000hz. The woofer's range is 25 to 800hz and the tweeter only has a top end extension spec of 40k.
** The site does not give a crossover slope on any of it's drivers.
So my guess would be to locate a driver that'll operate between ~600 Hz to ~8000 Hz.....
to account for overlap in the crossover and provide margins for bandwidth...

[3LB]

that's a -12db crossover slope...the natural rolloff slope of any driver is -6db...why do you need to add such a large resistor? Does the driver give an impedance rating on the back? I'd be surprised if it isn't an 8ohm driver...I'm on my phone and can't see the values of the components, those values will not only tell you x-over points but the driver impedance, because you already have those points listed.

[Cu-Melter]

Hello 3LB-
The mids are Six Ohm (6), 40 watts

[3LB]

without knowing the DC resistence value of a driver, its hard to say what your best course of action is...I would suggest however, that you replace both mids, cuz its going to be a challenge to find a new mid that'll sonically match your decades old one. Is it a sealed back driver?

I wonder what the ohm rating is on that L-pad? Does it say on that sheet?

If yer feeling real discouraged, you could mosey over to audio asylum or DIYaudio.com and post the question there. Madisound has a forum.

or you could roll the dice on your resistence in parallel idea and give listen.

[Cu-Melter]

The L-Pad resistance is 8 ohms typical. I don't have a VOM, but my guess is that the DC resistance on the driver would run ~4.8 to 5.6 ohm.....I realize this guesstimate serves little purpose for this discussion/evaluation. The driver is not a sealed back unit, however. The cabinet provides a plastic 'well' that prevents woofer back waves from coloring the midrange.

Madisound was the name I was trying to remember.....some other posters have just typed 'MSound'...left me in the dark, as it were-
Thanks for your help and insight. I'm concerned that if I replace w/a typical 8 ohm driver, I'm going to realize a decibel drop off, making the whole system sound weak in the mid areas.
Of course, I suppose I could just dial back on the bass knob of the intended audio source signal.

Regards-Ed

[3LB]

The L-Pad resistance is 8 ohms typical. I don't have a VOM, but my guess is that the DC resistance on the driver would run ~4.8 to 5.6 ohm.....I realize this guesstimate serves little purpose for this discussion/evaluation. The driver is not a sealed back unit, however. The cabinet provides a plastic 'well' that prevents woofer back waves from coloring the midrange.

Madisound was the name I was trying to remember.....some other posters have just typed 'MSound'...left me in the dark, as it were-
Thanks for your help and insight. I'm concerned that if I replace w/a typical 8 ohm driver, I'm going to realize a decibel drop off, making the whole system sound weak in the mid areas.
Of course, I suppose I could just dial back on the bass knob of the intended audio source signal.

Regards-Ed
you could just make sure and get a sensative mid. Try Parts Express and MCM electronics as well. Happy hunting.

[Cu-Melter]

3LB-
What's your take on just using a pair of 5" full range drivers?

[3LB]

3LB-
What's your take on just using a pair of 5" full range drivers?
That's actually a good point...there shouldn't be much of a difference really, hell, you might improve the mids with a smaller diameter driver. Since the x-over point is 800hz, the mid isn't producing any significant midbass. You might also have a better varierty of drivers to choose from, although 6ohms isn't a standard impedence.