MCM 55-2421 T/S Parameters and thoughts

[greg_mcquaid]

Well i am in the process of wanting to build i nice small HT/music sub built around the mcm 55-2421 but i cant find any t/s parameters for it anywhere. And one other thing is i want it to be able to play down to the 20 -30 region, is that possible with this driver?

Greg

[Zaph]

Actual measurements:

Fs=30.95 hz
Qms=12.2863
Qes=0.2365
Qts=0.2320
Vas=23.88 l
SPL=86.59 1w/1m
Re=3.4
Le=2.42
BL=13.15
Xmax=16mm P-P

This was from an early model, hopefully the specs have not changed.

[BillFitzmaurice]

Those specs are pretty close. The claimed Fs is 24 Hz, but it does measure out more like 30 Hz even after break in. This link is to a measured SPL chart of it in a small (3.3 cu ft) 40 Hz folded horn. With the right cabinet it will work fine to 20Hz.

http://hometown.aol.com/billfitzmaur...mtbrand=AOL_US

[greg_mcquaid]

Thanks for the info but can someone point me to a program or spreadsheet that can calculate the sizes of the folded horn. And is there anyother way of reaching 20hz without a foled horn like ported design?

Greg

[BillFitzmaurice]

You only need a horn if you require high SPL, for instance to run it with a low power tube amp or to match up with high sensitivity mains. For more normal SPL just model it up in WinISD in ported box, 4th order and 6th order alignments to find what suits your requirements. The Qts is a bit too low for a sealed box or TL. I also wouldn't be too concerned about trying to get flat to 20 Hz. down 10-15dB there is quite adequate, but if you really want that kind of extension you'll have to look at larger drivers.

[Patrick Bateman]

Originally posted by Zaph
Actual measurements:

Fs=30.95 hz
Qms=12.2863
Qes=0.2365
Qts=0.2320
Vas=23.88 l
SPL=86.59 1w/1m
Re=3.4
Le=2.42
BL=13.15
Xmax=16mm P-P

This was from an early model, hopefully the specs have not changed.

I've personally measured four of them which I purchased from MCM in 2006, and these specs are right on the money.

[Studio Au]

@greg, may I ask where you purchased these drivers, wanting to make a push pull sub, like the one featured here.\

http://www.instructables.com/id/Building-a-tapped-horn/

In Bristol too.

Thanks

[tb46]

Hi greg_mcquaid, and Studio Au,

These drivers will work in this enclosure. Post #30: Dual 8" tapped horn = TH-SPUD

Regards,

[Studio Au]

@Oliver, There are a couple of links, the Tang Band ones or the B&C.

Low cost is a priority and uk availability. Parts express international shipping is rather costly!

[ODougbo]

Just jumping on the tread; I have a bunch of them laying around :-/


btw....

Silly's 1st Sub -- 8" MCM 55-2421