OB subs: Best compromise?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Since we can't have everything when it comes to T/S params, what compromises work the best or hurt the least? For example, which of these would you chose? (Assuming all are about the same $) All are 15”.

Qts Fs SPL Xmax
driver 1 1.446 40 92 4.05
driver 2 .88 25.6 87.3 14
driver 3 .7 29 92 9.4
driver 4 .67 26.7 90 6

I want accurate music reproduction first, HT second. Not worrying about impressing (or bothering) the neighbors - nearest is about a quarter mile :)

I’m thinking of possibly putting these in an H-frame, approx. 24”x36”. Could I set it on the long side and put the TV on top? Well, I know I COULD, but is it a good idea?

If I do a W frame is there a simple way to calculate the spacing of the middle section? Sorry, No hablo calculus.
 
Thanks for the opinion. Sorry the formatting got messed up on the table, but I guess you figured it out. I would really like to use #1, it;s a cool looking alunimum cone, but that high Fs bothers me some, not sure if it would give me the opening notes of also sprach zarathrustra - I want to feel it.
 
I agree with number two.
Scale this up to a 15" driver.
 

Attachments

  • d_woof1.gif
    d_woof1.gif
    7.8 KB · Views: 391
I gotta go with the croud and vote for door # 2 due to the Fs and Xmax. Loosey goosey (quite high Qts) at 40hz seems like a problem I wouldn't want to have to design around for driver #1, at least not for a sub.

Regarding cavity width for a W baffle, I had the same question and couldn't find a hard answer. The height and depth dimensions can result in cavity resonances, but they're well above a sub's frequency. You just don't want it too narrow to create air flow noise, so the narrowest possible with the push/pull alignment leaving reasonable clearance if the pole is vented should be fine.
 
How about if I made all three chambers the same size? Then I could try facing the drivers either way.

#2 is a Volfenhag - anyone ever heard of/used one? It's an auto sub, but try to find a "real" home audio sub with good OB specs for a reasonable price - $50-60 each
 
MtnBob said:
Thanks, Tom. I've got that gif saved somewhere. WHen I said middle section, I was thinking of a design I saw where the drivers were facing each other. Wonder where I saved that? :xeye:

You may want to rethink the drivers facing each other. Here is
a response from Roscoe Primrose to the question of why is it better to have them oppose each other rather than face each other....

Second order distortion cancellation. Remember, in a W baffle the drivers are moving in opposite directions, so one cone is moving towards it's magnet structure wile the other is moving away...

Peace
 
I think Tom didn't mean "oppose each other". You want one facing the basket of the other, so they are facing the same direction but moving in opposite directions. They both fire into the chamber at the same time. One is pushing out of its basket and the other is pulling in, thus Push/pull. I did some experimenting and there is an audible difference at medium to high volumes and it becomes even more important with cheaper drivers.
 
johninCR said:
I think Tom didn't mean "oppose each other". You want one facing the basket of the other, so they are facing the same direction but moving in opposite directions. They both fire into the chamber at the same time. One is pushing out of its basket and the other is pulling in, thus Push/pull. I did some experimenting and there is an audible difference at medium to high volumes and it becomes even more important with cheaper drivers.


Yes...what he said :)
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.