Need advice for 210 VOTT mods

[RacerXtreme]

I bought 4 of the big 210 VOTT cabinets nearly 20 years ago from the George Burns Theatre (near Detroit) when it closed. Enjoyed the 515B's that were in them for years, but eventually started wishing for a little more performance. Read Jim Dickenson's article on some of the cabinets attributes and drawbacks. They need to be stiffened up a bit, the port volume reduced (did that), and add some more insulation (did that but need more). Most Altec experts seem to recommend upgrading to 515G's. For what they cost tho, and the fact that I can get JBL's for dealer cost - the 515's seem like they may not be the best choice. I have a good friend that has 30 DJ's working for him and JBL's reputation, reliability and performance are easy to see.

My question is this: With all the different 15" woofers available, should I just experiment and try to find some that are best suited to a large enclosure?

I realize that some may view this approach like putting a Chevy motor in a vintage Ford, but it happens all the time.

This system will primarily be for home use in a 20' by 40' garage, tho I may break them out occasionally for large parties. In other words, 1000 watt woofers aren't really necessary. Found some 400 watt Eminence 15's for around 80 bucks ea. Black Widows for around $125 - JBL's are even more. Considered putting an 18" sub in the lower part of the box, then time-aligning them with my Rane AC23 3-way stereo electronic x-over, but I'm having second thoughts. Been looking at Theil-Small parameters for hours.

Any ideas? Thoughts?? Thanks for the help.


Guy

[Roland N R]

If have 515Bs stick with them as these are almost as good as the 515G. I believe we already discussed the possibility of a subwoof in the lower vented compartment while still maintaining vented output of the horn. As far as other 15" drivers....Eminence does not generally use edgewound VCs so quality is not as good. JBL are better but as you increase power tolerance the VC gets heavier and you get decreased transient response. Likely the thermal
overload you experienced with the Altecs was due to trying for disco bass when the 210 cab is intrinsically bass limited in that regard. Either way use whatever large magnet 15s" you have and also use a built in sub with an 18" or two 15" and biamp with a rane delay to the sub. It so easy to do and the results are great. I use 2x4s" on the outside to reinforce three a side and back.

[stpower]

Racer,
I use 210 enclosures with the Dickenson mods and can say that stiffening up the horn flares and bracing the box makes a big improvement. If you have room, use the wings Altec used with the 210.
Otherwise, use a cross-strut on the sides of the horn mouth to brace them.
For home use I think the 515-b is the best choice.
The bass to about 40hz is tight and very fast and clean. It doesn't have the thump and boom some like, but is more natural sounding to my ears.
I like Rolands idea of a built-in subwoofer of an 18 or 2 15's. This would fill the missing bottom octave while maximising use of the box.. I plan to either go this route or try an Edgar seismic or Labhorn sub eventually.I think the horn sub may have a better subjective blend.
stpower

[Mirrophonic Sound System]

Join the four 210s together with bolts(like in an A2).
This will provide extra bracing and will increase the
effective horn size to full bass range (like a multicell's cut-off
is the sum of the component horns).
Run them upside down with the horns to the floor for
even more horn freq extension.
Now seal off those disasterous reflex ports and run
low mass 1950s woofers with an FS of around 30 Hz.
The internal cabinet volume should be large enough
as to not raise the Fs to any degree. Equalize to
taste if you prefer.
Now get ready for the best bass in town!

[budmonty]

Originally posted by stpower:
Racer,
I use 210 enclosures with the Dickenson mods and can say that stiffening up the horn flares and bracing the box makes a big improvement. If you have room, use the wings Altec used with the 210.
Otherwise, use a cross-strut on the sides of the horn mouth to brace them.
For home use I think the 515-b is the best choice.
The bass to about 40hz is tight and very fast and clean. It doesn't have the thump and boom some like, but is more natural sounding to my ears.
I like Rolands idea of a built-in subwoofer of an 18 or 2 15's. This would fill the missing bottom octave while maximising use of the box.. I plan to either go this route or try an Edgar seismic or Labhorn sub eventually.I think the horn sub may have a better subjective blend.
stpower

<font size="2" face="Verdana, Helvetica, sans-serif">Hi. I noticed in your reply to RacerXtreme that you mentioned you have modified your altec 210 using the Jim Dickinson plans. I have been looking for these plans for over a year with no results. Would you be able to help me in this regard........PLEASE! I would be willing to pay any reasonable expense involved in procuring these plans. budmonty

[Roland N R]

Jim Dickinson plans are listed free of charge at the Sound Practices website look under Altec. Basically the mods are stiffening the cabs and reducing internal volume by removing one foot from the bottom of the cabs. If dont' want cab alterations obviously can accomplish the same the same in other ways.

[budmonty]

Thanks Roland. I checked out that page which contained the article by Jim Dickinson. It seems all too simple to just cut off a foot and reinstall the end piece. I would like to leave the cabinet intact if I could. I was thinking of putting the high frequency horns within the enclosure in the space that is to be cut off, by just partitioning it. However it appears that the horns have a little too much hight (abt. 13 1/2") for that.
The bass ports are about 24" high. In your opinion would an extra inch or two at most make any significant difference in the bass response or is the port size quite critical? I appreciate your input. Thank you very much. Bud

[Roland N R]

Bud:

I don't think a 1 1/2" more or less will be critical you can add fiberglass to add apparent volume to compensate. Also you can just add a shelf at one foot from the bottom to reduce the volume w/o cutting the cab.

[budmonty]

Thanks Roland. I intend to investigate installing the high frequency horns within the enclosure this weekend. I think it will be feasable. Before I do that I will hook up the speakers to an amp and see how they sound as is. Then I will have something to compare to when the change is made. If the change is not acceptable then it will be easy enough to undo. I will let you know how it works. Thanks again. Bud.