MCM 21" tuned LOW thoughts? - Page 2

siruis815 · 19th February 2013, 10:21 PM

@abcdmku - What's the tuning on that? Any equalization going on?

I wish I could go bigger, however even 7cuft/driver x4 is pushing it. 5cuft would be even better, however then I definitely run into excessive gain and power requirement issues - 14cuft/driver is what I'd like to do.

abcdmku · 20th February 2013, 04:59 PM

I'm out right now, but when I get back to my computer later today I'll post the frequency response, and the rest of the data.

mr. doom · 20th February 2013, 06:19 PM

I do not see any benefit of using this driver for home applications. The box required is huge and with a LT circuit you will probably be getting some motor noise from it if you push real power through it.
It is an interesting driver being 21" with a 4" voice coil and die cast basket for only $120.

My MCM experiments with the cheap cast pro drivers have met my expectations but you get what you pay for.

Nelson Pass · 20th February 2013, 06:39 PM

They work in an open baffle though.

siruis815 · 20th February 2013, 11:48 PM

Quote:

Originally Posted by mr. doom

... and with a LT circuit you will probably be getting some motor noise from it if you push real power through it.

Interesting - any reference material for this?

Quote:

Originally Posted by Nelson Pass

They work in an open baffle though.

Why yes, yes they do

Mr. Pass - any personal experience with these?

Nelson Pass · 21st February 2013, 04:02 AM

If you mean the woofers I can see, no. What are they?

siruis815 · 21st February 2013, 10:19 AM

No - the MCMs are attached to the panels hanging from the ceiling

Not the ideal location for them, but it actually does work. I think it's more of brute force than good design.

The drivers on the floorstanding OBs have been replaced by a 10" B&C Mid and Selenium CD (w/15" horn)

mr. doom · 03:36 PM

Concerning motor noise.

Quote:

Originally Posted by siruis815

Interesting - any reference material for this?

Only from personal experience with the15" MCM cast drivers and driving them past x-max.

I have not tried the 21" but was looking at using them for some budget reflex bins and decided that some neo 18's with 30% more (measured excursion) and much lower vas would be better for my purposes.
The neo drivers cost twice as much but weigh 25lbs less which is huge for me.

siruis815 · 22nd February 2013, 03:41 PM

Cost for me was definitely an issue. If I could go back, I'd probably end up going with 2 FI IB3-18s (~30mm Xmax) at $254 a piece. A bit more cost, but pretty much the same output out of half the amount of drivers.

rafaro · 29th March 2013, 08:54 PM

Hello ABCNMKU you said:

"I just built a ~12 cu ft enclosure for the MCM 21 inch. It has two 2"x22.5" and 20 inches deep, gets a solid 35hz"

"I'm out right now, but when I get back to my computer later today I'll post the frequency response, and the rest of the data."

I can modify 8 cu ft box to 12 cu ft can you provide additional data. 35Hz F3 is about right for my needs

Rafaro

29th March 2013, 08:54 PM	#20
rafaro diyAudio Member Join Date: Feb 2006 Location: Guatemala	MCM 21" Hello ABCNMKU you said: "I just built a ~12 cu ft enclosure for the MCM 21 inch. It has two 2"x22.5" and 20 inches deep, gets a solid 35hz" "I'm out right now, but when I get back to my computer later today I'll post the frequency response, and the rest of the data." I can modify 8 cu ft box to 12 cu ft can you provide additional data. 35Hz F3 is about right for my needs Rafaro

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19th February 2013, 10:21 PM	#11
siruis815 diyAudio Member Join Date: Dec 2011 Location: NC	@abcdmku - What's the tuning on that? Any equalization going on? I wish I could go bigger, however even 7cuft/driver x4 is pushing it. 5cuft would be even better, however then I definitely run into excessive gain and power requirement issues - 14cuft/driver is what I'd like to do.

20th February 2013, 04:59 PM	#12
abcdmku diyAudio Member Join Date: Mar 2012	I'm out right now, but when I get back to my computer later today I'll post the frequency response, and the rest of the data.

20th February 2013, 06:19 PM	#13
mr. doom diyAudio Member Join Date: Mar 2006 Location: Montana Missoula	I do not see any benefit of using this driver for home applications. The box required is huge and with a LT circuit you will probably be getting some motor noise from it if you push real power through it. It is an interesting driver being 21" with a 4" voice coil and die cast basket for only $120. My MCM experiments with the cheap cast pro drivers have met my expectations but you get what you pay for.

20th February 2013, 06:39 PM	#14
Nelson Pass The one and only Join Date: Mar 2001	They work in an open baffle though.

21st February 2013, 04:02 AM	#16
Nelson Pass The one and only Join Date: Mar 2001	If you mean the woofers I can see, no. What are they?

21st February 2013, 10:19 AM	#17
siruis815 diyAudio Member Join Date: Dec 2011 Location: NC	No - the MCMs are attached to the panels hanging from the ceiling Not the ideal location for them, but it actually does work. I think it's more of brute force than good design. The drivers on the floorstanding OBs have been replaced by a 10" B&C Mid and Selenium CD (w/15" horn)

22nd February 2013, 03:41 PM	#19
siruis815 diyAudio Member Join Date: Dec 2011 Location: NC	Cost for me was definitely an issue. If I could go back, I'd probably end up going with 2 FI IB3-18s (~30mm Xmax) at $254 a piece. A bit more cost, but pretty much the same output out of half the amount of drivers.