anyone with experience with 421 8LFs?

[Phil-G]

i kinda like these drivers. my questian really should be does anyone have a prefered application? the specs suggest they play really high. a little better than 5000-6000.
i was kinda thinking of a quad parallel/series for guitars. or,,,, maybe not

[GM]

MI horn driver for 816, 817, 828 and prosound 210, 211 cabs, so lots of [combo] horn options.

GM

[mah]

The 817 series seems to be preferred for guitar. The 421-8h probably more so than the 421-LFs in the larger drivers for guitar, with the latter preferred for bass guitar, but there are no strict rules.

[Phil-G]

thanks GM. i didn't think of 421s as horn compatable drivers. and i've wanted to give my take on 200 series cabinets. how would they compare to 515s? i have 4 515 GHPs but i just don't see them going very low. 50hz seems kinda anticlimatic for a 210. i don't know, which would sound better?

[GM]

You're welcome! There's few Altec drivers not suitable for some type of horn loading such as the high Qt, dual cone 420 and similar. Didn't know 515GHPs [and several others] existed until I joined this forum.

?? 210/211 are ~70 Hz horns reflex tuned to 35 Hz and meant to be EQ'd.

Don't recall ever using the 421LF, just the 'A' and 8H. Frankly, I don't understand all the overlapping models and some of the marketing hype such as listing the 515 as only good to 1 kHz, but the 416 to 1600 Hz when it's the 515 with a much wider useful BW and why it sounds 'sweeter', though apparently kind of academic once re-coned or new GPA based on some measurements I've seen that shows them as virtually identical from ~300 Hz-up, but thankfully it's 515's.

Anyway, I can only guess that the main performance differences between any 515 and 421 in any cab alignment will be mostly a matter of mids/HF 'brightness', increased distortion at higher power due to the MI driver's 'chrome dome' and lower linear travel plus its lower efficiency making a bit more tonally balanced [mid] bass.

The bottom line for me has never changed, excepting MI or infrabass app, the low Fs, Qts/high Vas 515 is the most flexible, best overall performer of the ones I'm familiar with, so between cab loading and some form of EQ I can make it perform best overall to my ears anywhere a modest power handling 15" is a viable option.

Unfortunately, I get the impression that GPA can no longer properly repair/replace my drivers, so would have to sell them and buy new, though not sure which version comes closest overall since there's no accurate response, impedance plots to compare, making me wonder if I should buy a well documented modern day high power mid-bass horn driver and just use [1]/channel.

GM

edit: to clarify a bit...........

My 'concerns' aren't with GPA's product quality, which with one documented exception [Panomaniac's] has AFAIK been on a par with Altec's 'glory' days WRT Quality Assurance [QA], i.e. attention to overall detail and measured specs being well within the industry's claimed +/- 10% [many manufacturers aren't even in the 'ballpark'] and well above what they 'sank' to as it was being gutted to just little more than a name; but with Altec's too often changing a driver's specs [sometimes repeatedly] over time without it being apparent by having a new suffix or at least a version update to differentiate it from a prior design and make known in its description any changes pertinent to a designer and/or end user.

This, combined with someone posting that GPA only has tooling/replacement parts/instructions for the way they were made/re-coned at the time of the sale to GPA and some measured specs [may have been WRT Pano's unfortunate situation, which should be a mandatory required reading 'sticky' note for anyone contemplating buying used Altec drivers, especially AlNiCo], published frequency responses of their re-cones and new drivers in particular strongly implies that while they should have no problem matching mine's [4] matched sets of T/S specs; doping and/or whatever else is done to get the desired frequency response/tonal balance seems a bit too 'iffy' for me and not willing to gamble as Pano did if I should ever have the need.


Some have asked me if originals in general or mine in particular 'sound' or perform better overall than GPA's, but with so many [subjective] variables to consider plus having only auditioned GPA's 515-8G in a DIY 'chopped down' 825 to be a better performing version of an 816, about all I can say is that without either copious measurements and/or outdoor 'free air' A/B comparisons I can only speculate that with modern electronics they probably perform same-to-better overall and with period correct tube electronics, not so much. This isn't to imply that they won't sound good, just maybe different than what the factory approved 'voicing' was.


In short, WRT point source [cone] drivers and horn driver diaphragms, I recommend buying GPA over used whenever possible unless either the buyer knows they are original and been well taken care of or plans to have GPA do a complete overhaul and if the latter are aluminum, then by now they are so work hardened that they should ideally only be used when there's a super tweeter horn.


WRT re-coning, I recommend doing all or none at least with AlNiCos and paying for a proper drain/re-zapping to within tolerance if not part of the re-cone price as this audibly impacts their overall performance as much, if not more than, anything else [doping/whatever]. Other type motors should at least be checked and if not already an option, paying for measured T/S specs should be considered if not either willing to measure them or planning on a custom cab alignment.


GM

[bowtie427ss]

Frankly, I don't understand all the overlapping models and some of the marketing hype such as listing the 515 as only good to 1 kHz, but the 416 to 1600 Hz when it's the 515 with a much wider useful BW and why it sounds 'sweeter',

The answer is in the 515's impedance curve. In the horns it's impedance is nearly ruler flat at 16ohms from just above resonance to just a tad past 500hz(much flatter than any other Altec woofer) where it begins it's continuous rise with frequency.

[GM]

Hmm, only when they had zobels in the XOs.............otherwise they're only ~flat through the horn's gain BW, same as the other models. Regardless, an awfully obscure way to differentiate them, downplaying their superior overall performance.

GM