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MCM 1900 rigging the mid and high?


godfried

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We (an volunteer driven cultural centre in the Netherlands) acquired a good working MCM1900 system (the touring version with handles and aluminium rims). 4 way, so MWM, MSSM, MSM & MTM (the 5 piece Motorola version). This is for our venue (33ft wide * 60ft * 12 ft high) for 300 persons. Mostly used for dj's with hardcore, techno etc. We use a Rane MA6  6*100w amp and a DBX 234 XL crossover, at 350hz and 1khz. Linkwitz-Riley 24 dB per octave filters. The gain for the MWM and MSSM are set to 0db, the gain for the MSM is set to -6 db. The MTM is coupled to the MSM.

 

The sound and volume are incredible. But for a better reach, spread and for flexibility in the venue we like to fly everything except the MWM. Is there any experience how to do this. The doubts are in the high crossover from the MWM to the MSSM. 

 

Any one with other, better ideas is welcome. Also other frequency's etc.

 

regards, on behalf of the Culture Cooperation Brebl, Godfried

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Hi DJK, thank you for the reply. we know how to do it, but the question is, is it wise to do it?

In modern setups (sub / tops) the crossover point is mostly max 150hz, often lower. But with the MCM 1900, the crossover between MWM and up is set to 350hz. Would it be wise to fly them, sound wise. Does anybody know if this is done, can we lower the crossover frequency, or will that damage the MSSM?

 

regards, Godfried

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  • 2 weeks later...

MSSM is a 10" used as a compression driver, probably no harm in lowering the crossover as it stands that unit is only handing about an octave, yet a critical octave from 100-30 hz. Why is it needed to lower the crossover point? More overlap does not necessarily help in coverage with the LF being stacked and Lo mid being flown in my opinion. 

 

DJK's advice on bolting them together using threaded rod is right on, they need support THROUGH the cabinets, not hung from the top panels, certainly NEVER SUSPENDED FROM HANDLES. 

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thank you for the input, we're gonna give the setup a try tonight, not rigged to the ceiling, but just as it is. And i'm gonna fiddle around with the crossover frequency for the MSSM. If we're gonna ring it, is it really necessary to hang them above each other, or kan we ring them beside each other. We ave obtained a Driverack 260, so we'll be able to use other filterslopes.

 

regards, Godfried

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It sounds best to cross flown mid/HF cabinets at 100hz (or less), but the Klipsch may not go that low.

 

Measure them and see what will work, I'm guessing 200hz may be in order. As long as they are directly above the bass units it should not be a problem to a listener back just a few feet.

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We (an volunteer driven cultural centre in the Netherlands) acquired a good working MCM1900 system (the touring version with handles and aluminium rims). 4 way, so MWM, MSSM, MSM & MTM (the 5 piece Motorola version). This is for our venue (33ft wide * 60ft * 12 ft high) for 300 persons. Mostly used for dj's with hardcore, techno etc. We use a Rane MA6  6*100w amp and a DBX 234 XL crossover, at 350hz and 1khz. Linkwitz-Riley 24 dB per octave filters. The gain for the MWM and MSSM are set to 0db, the gain for the MSM is set to -6 db. The MTM is coupled to the MSM.

 

The sound and volume are incredible. But for a better reach, spread and for flexibility in the venue we like to fly everything except the MWM. Is there any experience how to do this. The doubts are in the high crossover from the MWM to the MSSM. 

 

Any one with other, better ideas is welcome. Also other frequency's etc.

 

regards, on behalf of the Culture Cooperation Brebl, Godfried

If you plan to bring DJ's in make sure to have appropriate High Bypass filters  and limiter settings on the amps  as it has been my experience that they will damage the LF drivers if given the chance. If I rent my system to do DJ gigs I have them plug into my mixer so I can control the output via my iPad.

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I didn't answer before because I don't have experience with these massive pro systems.

If I read correctly, the issue is that the units which are elevated handle freqs above 350 Hz and the bass unit is on the floor. Will that cause some anomaly which can be heard?

One reference point is the conventional settings of a home theater system which crosses over to a subwoofer at 80 Hz. But, what I read is that this 80 Hz was selected because it is two standard deviations (statistics, here) below the freq where the most sensitive listeners, hearing the most demonstrative program, can localize the sub. Okay, fine, but I don't find a listing of just what the standard deviation is. So this doesn't tell us how far you can deviate and go to a higher freq.

Contrary to what we read, it is not whether bass can be directional. Granted, you need huge "antenna" to get bass to beam.

But, our ears only about eight inches (about 10 cm) apart, and thus while they (as receivers) can triangulate high freqs (short wavelengths) they can't triangulate low freqs (long wave lengths). E.g. outside, you can hear thunder, but not the direction where it is coming from.

I don't have it here before me, but there was a paper in the Klipsch Papers describing a panel discussion. There it was speculated, though by learned people, that the ability to localize "bass" started at 400 Hz. If so, that would put you someplace at a marginal situation. But I'd say, and okay situation, and not something to worry about.

I can only suggest that you play a 350 Hz tone through the system "as flown" and switch back and forth between the speakers. My guess is that it will be okay. Part of the reason is that our ears localize left and right, but not very much up and down.

Let us know.

WMcD

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