# MCACC crossover selection - fr/cntr good low end vs. sur fair low end



## GCG (Aug 22, 2013)

I'm on the fence with my crossover selection (old Pioneer Elite VSX-43TX soon to be replaced with a new SC-71). below is list of the speakers in a 5.1 system

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Speakers
Front's - Infinty RSb's

Introduced: 1978
Dimensions: 63 x 35 x 25 cm
Bass: 1 x 25 cm
Mids: 1 x 12 cm
Highs: 1 x EMIT (Yup, still kick'n with the original diaphragms) 
Enclosure Type: Acoustic Suspension
Suggested for amplifiers with: 35-200 Watts per channel
Frequency range: 45 Hz - 32 kHz
Crossover frequencies: 600 Hz, 4000 Hz
Suggested price (Then - pair): $580 
Woofers rehung in Late '90's and in good shape.
http://www.infinity-classics.de/mode...ence-klein.htm

Center - Infinity Video-1

Frequency Response: 58 Hz - 20 kHz +-3dB 
Sensitivity: 89 dB @ 2.87 volts, 1 meter 
Power Rating: Use w/amps rated between 5 - 100 watts RMS for Center Channel 
Enclosure Type: Acoustic Suspension 
Crossover Frequency: 4.5 kHz 
Nominal Impedance: 8 ohms 
Drivers: Dual 5-1/2" Polyproplene woofers, 1/2" Polycarbonate tweeter.
Magnetically shielded for video applications. (An old spec dating back to CRT's for you youngsters)
Dimensions: 18-1/4" wide, 7" high, 6" deep

Surrounds - Infinity SM-65

Power Rating: 10-100 Watts
Freq Response: 78Hz-25kHz +/- 3db
Crossover: 4.5 kHz
Efficiency: 94 db SPL, 1 watt/1 Meter
Impedance: Compatible with 4 to 8 Ohms
Drivers: 6-1/2" Polypropylene Coated Woofer, 3/4" High Output Polycell Tweeter
Dimensions: 8" wide x 13-1/4" High x 7-1/2" Deep
Rear Ported
http://www.infinity-classics.de/tech...15-125-155.pdf


Read more: http://www.hometheatershack.com/forums/rew-forum/72236-noob-new-setup-soon.html#ixzz2poaFEhLa

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The question is can I cross the sub @ 80 Hz considering the fronts and center low end (45 & 58 Hz respectfully) even though that is crowding the low end response of the surrounds @ 78 Hz? I don't have a REW sample as yet and I'm aware that the results may make the question mute.


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## Prof. (Oct 20, 2006)

80Hz. may be a bit low with those specs..I would be more inclined to make your xover at 100Hz..and set your speakers to "small"..


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## GCG (Aug 22, 2013)

Thanks for the reply. Just thought I might get away with 80hz on the surr's. I've read the surr's don't necessarily get as much of the low end.


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## Prof. (Oct 20, 2006)

Generally your xover frequency should be approx. double the lowest frequency of you front speakers..
In your case the centre speaker at 58Hz. would require a xover at 100Hz.

Since there is no separate xover adjustment for the surrounds with MCACC, it's not so critical..
My surrounds are 75Hz - 22KHz. and my fronts are 30Hz.- 20KHz.and I use an 80Hz. xover..
Best thing to do is to try both and see which one appeals to you..It's not set in concrete..


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