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MCM 53-5165

edited November 2016 in Hard Data
In-box measurements of MCM 53-5165

http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-53-5165-/53-5165

Surface mounted in a Denovo 0.23 cubic foot enclosure

http://www.parts-express.com/denovo-audio-knock-down-mdf-023-cu-ft-mini-bookshelf-speaker-cabinet--300-7062

Mounted on center axis, about 8" or so from bottom. 

Distortion, SPL accurate, 1M:



Extremely clean above 3K, and still very usable at 2K (with careful crossover work). However - that dip at ~3K is fairly pronounced and may be a turn-off for some people. It doesn't bother me since it falls right in the region that always sounds just fine with a dip. Slightly elevated top end, however, may lend some slight sizzle - but given the pretty much non-existent distortion in that area it will sound cleaner and more natural than the slight rise would otherwise indicate. 

Before anyone gets too excited about that dip, however - keep in mind this is a metal dome and as such, has a phase shield implemented. So, let us take a look at the off-axis:



That is out to about 30 degrees or so - seems to be a natural for a sloped baffle. 

That being said, if you use this tweeter - keep in mind that the dip at 3K will fill in off-axis, and trying to "fix it" in the crossover to get to a flat on-axis response will probably yield some pretty mediocre results so leave it in there - physics will take care of it. The top couple octaves smooth out nicely just a bit off-axis, as well. This tweeter will probably be great for speakers with a wide spacing and no toe-in. 

Speaking of off-axis, some additional evidence for why we don't trust polar models:



The breakup is not predictable using standard simulators, and in this case for maximum effect will require quite a bit of tanking - or at a minimum a dedicated notch at 8500 in addition to whatever other crossover you are using. 
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Comments

  • Hey Johnny, Look pretty good for $30...er I mean $18! What were the conditions of the last plot?
  • The woofer? Same cabinet - this is a two way I have been doing a start-stop with lol. 1M, out to about 30 degrees, same voltage as the tweeter measurement. MCM 55-2669.


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  • jr@mac said:
    The woofer? Same cabinet - this is a two way I have been doing a start-stop with lol. 1M, out to about 30 degrees, same voltage as the tweeter measurement. MCM 55-2669.


    Wow...No cure for stupid on my part. Thanks. 

    That dip at 3K would really be a non-issue. People worry too much about that crap. It is fairly high Q which Toole, Vance D. others all agree that a fairly sharp bandwidth (this is a hair broad) High Q (it dips fast over a a short band) dips are highly inaudible in-room.  I would take the dip for the rest of its performance and if you cross it at 3K ish to a 4" mid/woof, well?  
  • Yeah, not to mention it fills in off-axis. Flat on-axis is a wonderful thing, but if it comes at a price of significant blooming off-axis I don't pursue it. 
    Mzisserson
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