604E or GPA's 604HII/III - final decision after back and forth

[oface1]

GM,

I thought I saw a post about this design before somewhere and some posters mentioned your involvement in it. Did not know it was you that had a hand in that MLTL cab in the 6 moons article.

Since you had designed it or one very similar, would mind sharing it with folks who would like to see if this would be a design for them? I am interested in this desgin, or would I just go with any of the other ones I have seen?


Thanks for your contributions GM, I first came about your involvement back in my BIB period in the Diyaudio forum.I noticed you seem to knock out a lot calculations in your own time and never seem to get much recognition for it, Thank again GM.


-chris

[gortnipper]

ooops - deleted dupe post

<font color="#FFFFFF" size="1">[ December 01, 2008 04:27 AM: Message edited by: Gortnipper ]</font>

[gortnipper]

Originally posted by Gortnipper:
It appears to me that all four walls taper back to round. The pick isnt the greatest, since I took it with my phone. Looking at mine with a flash light you can see they do all taper to round despite the rapid taper at the end, and you can feel the wall thicken on the inside despite the outer sides being relatively flat.

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

[DaveCan]

Does the horn part come off easy enough? I was thinking it would be neat to try and make a copy out of wood (spruce) or do an exact cast in lead.. Perhaps some small sq improvements may be noticed with the wood or lead?

Dave

[gortnipper]

No - I asked Bill about that and he said it would be difficult to do. You can see that this one doesnt have a screen in the throat like it should - it made it past QC without it, which did not make him too happy.

David

[GM]

Good to know, thanks! Then it's an 'ideal' radial rather than the typical easier to make flared in only one plane radials.

What I don't understand though is why he didn't opt for a larger horn suitable for a ~900-1 kHz XO point where a typical 15" has its initial 90 deg beamwidth or even the original's 1.2 kHz XO point. My limited time with an original made the 604E sound a rather poor excuse of a coax overall in comparison, making me wonder why Altec shifted to a smaller horn/higher XO point unless it was purely for cost reduction.

GM

[Todd W. White]

Technically, it's an exponentially-flared radial horn.

As to why Altec went to the smaller horn from the B to begin with, my friend, the late Dr. Paul S. Veneklasen, who was on staff at Altec as a physicist at the time Alexis Badmaeiff did the change to the C-G series horn, HATED it!

I have a letter in his own hand from him on the subject stating "it was stupid!"

<font color="#FFFFFF" size="1">[ December 01, 2008 09:06 PM: Message edited by: Todd W. White ]</font>

[gortnipper]

Originally posted by GM:
...unless it was purely for cost reduction.

<font size="2" face="Verdana, Helvetica, sans-serif">I work for a company that makes consumer electronics, and every day we make stupid product decisions for that very reason.

David

[DaveCan]

I thought I read somewhere that the new III version had the Urei horn? Ok that was a dumb ?, I just looked and they are the Urei.. I'm still trying to learn all this stuff, sorry....

Dave

<font color="#FFFFFF" size="1">[ December 01, 2008 10:44 PM: Message edited by: DaveCan ]</font>

[selmerdave]

So Todd in that case why didn't Bill go for a larger horn?

Dave