M14s: I may have a pair

[VolvoHeretic]

Maybe you need to drag those things outside to measure them?

[Alien_Shore]

Maybe you need to drag those things outside to measure them?

I'm up for trying it, but it just makes me wonder how the recone could impact the FR that significantly? Is it possible there's something wrong with the new VC/recone job? Let me go compare the original NF measurement on the same scale with the recone NF response...

[Alien_Shore]

I pulled up the before-and-after recone measurements in Holm this morning and did some comparative scrutiny:



The biggest difference in the parameters of the two measurements was max amplitude (I had the volume turned up much higher for the post-recone measurement)

[Earl K]

Hi Mike,

> What ever happened here ( re; your search for an explanation of old vs new rehabbed woofers, etc. & holes in the mid-range ) ?

> Did these woofers ever breakin & then even out ( their Freq. response ) ?

BTW ;



> This 22 db vertical scale is a might severe looking ( exaggerating those peaks & dips into things that you won't be able to easily hear ).

> Try a 50db ( to the vertical scale ) instead. One benefit will be that things just won't look as bad ( as this microscopic like look-see makes it out to be ) .

[Alien_Shore]

Hi Mike,

> What ever happened here ( re; your search for an explanation of old vs new rehabbed woofers, etc. & holes in the mid-range ) ?

> Did these woofers ever breakin & then even out ( their Freq. response ) ?

BTW ;
> This 22 db vertical scale is a might severe looking ( exaggerating those peaks & dips into things that you won't be able to easily hear ).

> Try a 50db ( to the vertical scale ) instead. One benefit will be that things just won't look as bad ( as this microscopic like look-see makes it out to be ) .

Thanks for following up, Earl.
The primary thing I've been doing with my 14s is listening to them
I'm taking some time off work later this month, and will be working on my numerous Altec projects. I too am quite interested in running some additional FR curves on the 14s now that the woofers have had some time to break in. I will use your advice on the next round of measurements and get them posted up. Another thing I want to do is try the DE250's in them and see if they sound/perform better than the old 902s.

[Skywave-Rider]

If you haven't, try measuring only one speaker, mute the other. You'll get problems with HF cancellation otherwise, unless you are painstakingly precise in your setup. It looks to me like you had both running.

[Altec Best]

If you haven't, try measuring only one speaker, mute the other. You'll get problems with HF cancellation otherwise, unless you are painstakingly precise in your setup. It looks to me like you had both running.

Hey Skywave ! Nice to see you drop by !

[Alien_Shore]

Here are the original 2 M14 woofers (before reconing) as tested in Aug, 2012:



Maybe I'll drag out the testing gear and see if I can get some updated graphs...