420 @19hz

[valhallax]

i was messing around with the winisd program and found out that a 420a speaker in a 46 cu ft box will play flat from 19hz. ive read somewhere that in big boxes usable power decreases quite abit? also, this driver looks favorable for a sealed enclosure. but im not sure what qtc means? and what does it compare with hz? whats a good qtc? and will the 420a really play that low in a vented box. as it is, im supposed to usea 22 cu ft box with a qtc of .71?

[Old Guy]

I dunno. My experience with 420's frankly, is I think your software has been smoking something very powerful.

Hopefully GM will weigh in, but I mistrusted simulations before- I certainly do now. I say no way.

But I have been known to be wrong...

[bowtie427ss]

I was wondering if this wasn't a contemporary slang reference to "420".

Having "played" with 420's in the past i'd expect their performance at 19hz to be right on par with their performance at 15khz.

Tho claimed to be a FR speaker, i think i'd be more inclined to call it "extended range" than full range. According to analysis with Clio their response rolls off significantly above 6-7khz, and to my ears that biflex cone doesn't make bass with the same "cleanliness" of the 416.

This is just my opinion, but at lower levels in a near field, with the addition of a tweeter 420's can sing very nicely. Outside of that environment they're just a frame and motor begging to be a 416, but that's just my take on them. I'll take the "contemporary 420" over the vintage Altec in this case.

[Old Guy]

Originally posted by bowtie427ss:
I was wondering if this wasn't a contemporary slang reference to "420".

<font size="2" face="Verdana, Helvetica, sans-serif">Bah! Humboldt!

[bfish]

Out of curiousity I ran a 420A in WinISD, and got the same results, with the 22.332 cu/ft sealed box the preferred default selection. When run as vented, I couldn't get a satisfactory vent mach at all. 19Hz was Fb (box tuning), not the "flat to". A 40+ cu/ft box is, well, a closet.

I even checked T/S parameters against those in the library. Identical...

If I had 420s to build for, I'd measure the T/S of the drivers I had to be sure. If published specs are correct, I'd be considering an infinite baffle (built-in) setup.

[Old Guy]

I still wanna see it- I ain't saying the 420 is bad- I'm just saying I don't believe it will go flat to 20 in any cabinet.

Simulaions are just that. Building and testing is the proof.

please note- this is not meant as a slam against anyone. just saying I don't believe the simulation.

[Old Guy]

I just noticed the difference in your post bfish- you aren't claiming "flat to'.

[bfish]

I can't find it now, but somewhere on the web is an old pic of an Altec 15 mounted in a closet door (maybe a Duplex?). If the 420A numbers are right, that might be a good application for one, but unless you had room-symmetrical 'his-n-hers' closets, stereo might be a little tricky...

...not to mention the unknown damping effects of the stuff often found in a "hers" closet...

[valhallax]

i pretty much thought the sim was far fetched but what i was wondering about..the larger cabinets making a speaker able to "use" less power? and the whole qtc thing? a lower qtc is a higherfrequency response?

[zelgall]

I have learned to stay out of discussions with specs and documentation because I have neither. I do however have 2 pairs of the 16" 420's and a pair of the 15" ones. I put the 16" 420's into a 10cuFt cabinet based on results from various box software, with appropriate venting and also tried them with the vent sealed in the same volume. I had good but not great results with the vented box but sealing the port on the same box made a big difference. The bass was more than acceptable for the size of box as well as very tight and well defined. I have model 19's and 604-8G's in factory 620 boxes and a variety of DIY boxes of different sizes to compare to by listening and I think that the 420's are a very good speaker if you use a tweeter that can run down to 10K to fill in the top. I have never felt that the bass was either lacking or flabby compared to other Altecs that I own. They aren't necessarily the best for everyone but with the many different opinions on which Altec sounds best being put forward everyday, I feel that there is a large group of Altec lovers that would find the 420 to be a satisfying choice. And all of these opinions of mine are without years of professional experience or measurements, just my admittably poor hearing.