annunaki
Moderator
That's why they make respirators and vacuum systems.
Your resurrection of this build really has been leaning towards doing a pair of these again. I just need to find someone that can build them for me.Tomorrow I am taking the sub to myer emco and play a little bit.I have a buddy who is going to let me a/b it with what they have. I am sure he is going to freak out when he hears this thing. I cannot stress enough that this thing has destroyed anything I have heard yet.......
Sounds like marketing fluff to me.an interesting read on mdf vs a new "greener" panel product.
http://www.edesignaudio.com/pdf/EFS.pdf
MDF is heavier and less stiff than plywood. So all things equal a plywood box will have less resonances and be lighter than the MDF box. Additionally, MDF is hazardous to work with due to the chemicals used to bond the fibers.i'm curious (not arguing) why plywood was spec'ed for this. i would think mdf is a less resonant material and would be better. i imagine the bracing would level the field. so for the sake of curiosity, what would one loose real world if this was done in mdf vs 3/4" ply?
The cop who heard mine built one....i GOTTA quit reading this thread. that sub WOULD get me arrested.
It seems like you're on the other side of the city - now, that's one listening session I'd like to hear at Myer-Emco. My last trip to M.E. didn't reveal too many *all that good subs*. Sure, there were Velodyne, B&W - I think that's it for brands. I don't recall the price of the top model, though. This was in the main speaker/sub listening room. I'm not sure if they have better subs tucked out into the other theater and higher end spots.Tomorrow I am taking the sub to myer emco and play a little bit.I have a buddy who is going to let me a/b it with what they have. I am sure he is going to freak out when he hears this thing. I cannot stress enough that this thing has destroyed anything I have heard yet.......
Sure. Lots of it is marketing fluff when it comes to companies wanting to call their product "green". However, getting the formaldehyde out of the product was a major step. IMO, formaldehyde was too often used and many new homes would be full of it with some of the materials used.Sounds like marketing fluff to me.
I have to ask since I'm considering some 15" drivers for a new sub build.
Is this sub still very good to excellent without the DCX? Down the road I may get a DCX but for now if I built this sub it would be with BFD only and 600 watts.
Without the DCX you will need some sort of infrasonic filter. There are less expensive, less ideal, options such as the Reckhorn I have previously mentioned within this thread. The VQ with 600 watts and an infrasonic filter will be a superb subwoofer.I have to ask since I'm considering some 15" drivers for a new sub build.
Given my design constraints below would you still recommend this sub over a sealed 15" design?
600 watts
No DCX, only BFD
Though it will limit the low end response below 20hz (which I assume is the tuning frequency here) the Harrison Labs F-mod highpass filters at 20hz are a really cheap option. I believe they are around $30.00 or so. I used them on the BASH plate amp I did for lbolts20 as the enclosure was tuned to 21hz. They worked very well.Without the DCX you will need some sort of infrasonic filter. There are less expensive, less ideal, options such as the Reckhorn I have previously mentioned within this thread. The VQ with 600 watts and an infrasonic filter will be a superb subwoofer.
20Hz max, 18Hz will be fine. These values are chosen based on how they limit driver excursion.Does the subsonic filter need to start at the Fs of the driver or the F3 of the box or neither? I understand the subsonic filter, just not sure what frequency the filter needs to start at?
The F-mods are only 12 db/octave slope which I don't think is steep enough. If the roll off of the enclosure is already 24 db/octave is another 12 db/octave sufficient?Though it will limit the low end response below 20hz (which I assume is the tuning frequency here) the Harrison Labs F-mod highpass filters at 20hz are a really cheap option. I believe they are around $30.00 or so. I used them on the BASH plate amp I did for lbolts20 as the enclosure was tuned to 21hz. They worked very well.
Due to enclosure roll off and the F-mods it was an effective overall 36db/oct. slope beginning at 20hz.
So I guess 12db/octave is sufficient.... I recommend you put a second order highpass filter at 20Hz. This will act as a protection filter such that at high SPL at low frequencies (below 20Hz) there is minimal chance of the driver bottoming out.