MCA2550D 2.1 Amplifier mistake in specs or bad design

[stephed]

If you read the specs it says the sub is variable from 40-240 but the sat are fixed from 240-20k.
The way I see it if you adjust the sub off 240 you create a huge freq. gap.
What good is the sub adjust if you create a huge gap in you freq. response.

Any opinions on how this compares to the Keiga KG-3100 2.1 on madisound.
http://www.madisound.com/catalog/pro...roducts_id=369http://www.parts-express.com/pe/show...number=300-772

[jeffreynixon]

Re: MCA2550D 2.1 Amplifier mistake in specs or bad design

Looking at the Keiga specs with HP and LP x-over points apparently tied together makes me nervous about it rather than the MCA. Reason for this is that the "sub" is probably still rising in output around 250 Hz and what you are looking for is a probably lower electrical crossover point that will allow it to blend with the HP speakers. I suppose if the Keiga is electrical 4th order on both sides it would be OK. I confess I did not bother to look, if they say so. Depending on what your planned HP speaker/box/placement is it will probably not just stop at 250 Hz and will be putting out something. I won't even say that 250 Hz is a bit high for "serious" subs. Probably in the scheme of real things the MCA should work just fine.

[[email protected]]

Re: MCA2550D 2.1 Amplifier mistake in specs or bad design

If you read the specs...

[stephed]

Re: MCA2550D 2.1 Amplifier mistake in specs or bad design

My plan was to replace the amp in a klipsch ksw-10 (10") with a 2.1 amp of some form and then use it with the tv on the variable output (set tv speaks to off). The sats for now will be a pair of minimus 7's.

Would it be worth putting a cap or a 12db low pass on the sats woofer to cut the low end to the sats?


Ed

[jims]

Re: MCA2550D 2.1 Amplifier mistake in specs or bad design

My plan was to replace the amp in a klipsch ksw-10 (10") with a 2.1 amp of some form and then use it with the tv on the variable output (set tv speaks to off). The sats for now will be a pair of minimus 7's.

Would it be worth putting a cap or a 12db low pass on the sats woofer to cut the low end to the sats?


Ed

As far as cutting the lows to the sats, you'll have to check the impedance in the region of the crossover point. Often the woofer's impedance peak will be too close, and the high pass filter won't work very well. It definitely needs to be modeled.

Jim

[taloyd]

Re: confused!

Indeed this amplifier does have a fixed high pass filter starting at 240 Hz, it works well with the variable low pass filter because the roll-off is very shallow (Q of 0.5). At 60 Hz the satellites (HPF) output is only down about 3 dB

Isn't the -3db point what's considered the crossover point, as at that frequency, it'll sum back to unity? If so, if it's -3db at 60 Hz, isn't the crossover... at 60 Hz?

Although after reading this, I'm even more confused...

But a linear-phase HP seems good, especially with quality drivers (Mark Audio, Fostex, etc.)

confusedly,
-Tal

[daver]

Re: MCA2550D 2.1 Amplifier mistake in specs or bad design

and with a little tweaking the transition between the subwoofer and satellites can be barely noticeable. It is really a well designed 2.1 amplifier.

I'll vouch for how easy it is to adjust and how well it blends in with my 2-way pair. I mounted it in a vented box with a Dayton 8" DVC woofer. Maybe 5 minutes of playing with the settings, and I got full sound at my computer desk.