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Get familiar with the reaction system: Introducing the Reaction System
MCM-5670 Woofer Alignments . . .
Thought I would share my findings using these excellent drivers (very affordable/flexible) too . . . DUAL drivers in single enclosure . . .
1.25 cu ft / 35L - DUAL Drivers, SEALED enclosure, Qtc = 0.673, QA = 50
Input Power = 10.0 W, Distance = 2.5M, Angle = 20*:
Linkwitz Transform (LT) applied:
PEQ ONLY:
LT wins out slightly in Group Delay (GD) improvement however PEQ wins in Amp Power required AND Cone Excursion to achieve the graphed 96 db SPL
I don't find vented alignments to be useful for my needs but please post your findings for others to observe.
Comments
Steve, I see your power level is 10 watts in your SPL screenshot. Is it the same 10 watts in your Cone Excursion screenshot?
Yes, David - the 2nd sentence above stated 10W applied.
You know, when you put it that way...it's almost like it should have been obvious to me!
No worries, mate - I do the same thing when in a hurry, too . . .
Here is a ported model with dual 55-5670's.
2.4 c.f. tuned to 45Hz.
0.60 ohms Series Resistance. Qa = 50
160 watts, at 1 meter [Note, 160 watts is the max continuous power rating and at this level the drivers are not reaching xmax. I would NOT run these at 160 watts continuous power regardless of what my simulation is telling me
]
Note, this would require pretty big ports: 2 x 2.5 inch, 2 x 3.0 inch or 1 x 4 inch. However, they would be pretty short and port resonances would be way out of the band pass.
Transfer Function: F3/F6/F10 = 45/40/35Hz
SPL at 160w at 1 meter
Cone Excursion at 160w
Group Delay
They can dig reasonably deep as subwoofers but they want so much internal volume to do it. I was kicking around the idea of using these in an isobaric config instead of the Peerless 160f25pr01 isobaric for sub speaker stands.
Single isobaric pair In 1cf. Tuned to 29hz. I've got SA70s so they will only get up to 4.5mm excursion until about 23hz when they unload past xmax. I put a 3rd order lowpass fc-80hz as an example. F3 effectively becomes 27hz. 70watts will put a 2"x8.5" port at 28.5m/s. So probably precision port.
The plate amp likely has a 19 or 20hz high pass.
True, so worry free full send!
19hz high pass (2nd order) added to the above 70watt isobaric config, ported.
Curious if anyone has ever measured them to know how close actual TSP are to manufacturer data?
I measured 4 of them several years ago - IIRC all four were pretty close to advertised.
Chuck helped Geoff (then at MCM) with the measurements of them when they were being designed. MCM didn't have a standard method of getting them until then. IIRC, the T/S and FR that were published were a result of this collaboration. It's one of the reasons the 5665 and 5670 were as good as they were.
Just as they were hitting the market and getting good reviews, Newark took stock/receipt of all MCM products and closed them down.
It's just how it happened. MCM was on the verge of a revamped driver lineup, and poof(!), they were gone.
InDIYana Event Website
I've gotten a few measured specs that I play with. One I don't remember where I got.. I don't think it was my own measurements. Another I snagged from one of Ron_E's posts (I think that is what I used for the above graphs). They aren't quite as nice as the factory specs, but not way off.
I had a quad of them, still have 2. Yeah my measurements were not precisely the same as factory specs but close enough I doubt I could hear any difference at all. I was thrilled when I bought my 4 for only $26 each. At $14.90 what a total steal of a deal!
Looks like the price just shot up to $42.58!