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fEARful™ Part Ten (10)

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#723
think about what the midrange driver actually is doing, which also can get some Q boost form the xover network.
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Be really carefull with when designing a crossover that way. I also simulated a crossover for my 210 with coax mid/high unit. Since the midsection of the coax has a sensitivity of approx 95/96dB I want to add a bit more by designing the crossover in such a way that it gives the mid section a slight boost to get it to 98dB. But, when doing so the impedance can drop severely in the midband. A real impedance measurement is necessary when building a 3-way design like that.
 
#725
ko stradivarius said:
Hey all!
As usual I'm late to the party in regard to getting a fearful cab built. And now comes the "neo crisis". ;) sorry if this is an out of line question but does anyone know where to pick up a couple of in stock 18 sound 6NM410 from??
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I picked up (2) from audioauction.com. I think that is the name. They were sold in pairs. There was also an ebay action from the same seller only at a higher rate. Not sure if they have any left or not.

On a side note I just realized I forgot to put the styrofoam spacers in the mid chamber of my 12/6. Will that damage the mid? I have plenty of polyfil in there. I'm in the process of building another cab with the proper tools. (1st one was a prototype made with a jigsaw and lots of PL premium) Just didn't want to damage it until then. And I'm too lazy to take apart ths cab if not needed. The new one will be done in a few weeks.
 
#726
cableguy said:
I picked up (2) from audioauction.com. I think that is the name. They were sold in pairs. There was also an ebay action from the same seller only at a higher rate. Not sure if they have any left or not.

On a side note I just realized I forgot to put the styrofoam spacers in the mid chamber of my 12/6. Will that damage the mid? I have plenty of polyfil in there. I'm in the process of building another cab with the proper tools. (1st one was a prototype made with a jigsaw and lots of PL premium) Just didn't want to damage it until then. And I'm too lazy to take apart ths cab if not needed. The new one will be done in a few weeks.
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umm actually I would put that styrofoam in and remove the poly. adding poly actually makes the mid box work as if its even bigger on top of being too big so your really stressing the mid.
 
#727
mcapote said:
umm actually I would put that styrofoam in and remove the poly. adding poly actually makes the mid box work as if its even bigger on top of being too big so your really stressing the mid.
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Wrong. As someone who I think's been building cabs for others for some time now, you really ought to know better, AUTHORIZED or not. This stuff has been on the wiki and more recently my website for ages now.

Anyway.

cableguy, damping is covered for both the mid chamber and the woofer area on the website, about how to do appropriate damping. The damping is there to reduce bounced internal wave energy compromising the cone's frontal output.

As far as the styrofoam chamber reduction, that is something else entirely. The 18 Sound midrange drivers use it in conjunction with the crossover component values to get a proper transition. It adjusts chamber Q to fit better. No damage results from not using the sty - it just doesn't work as well without it.
 
#728
greenboy said:
Wrong. As someone who I think's been building cabs for others for some time now, you really ought to know better, AUTHORIZED or not. This stuff has been on the wiki and more recently my website for ages now.

Anyway.

cableguy, damping is covered for both the mid chamber and the woofer area on the website, about how to do appropriate damping. The damping is there to reduce bounced internal wave energy compromising the cone's frontal output.

As far as the styrofoam chamber reduction, that is something else entirely. The 18 Sound midrange drivers use it in conjunction with the crossover component values to get a proper transition. It adjusts chamber Q to fit better. No damage results from not using the sty - it just doesn't work as well without it.
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Authorized for what? Im not selling your plans. every box ive sold has been sold for my cost. I built most of them for myself and used them then later sold em to try another build. The last one was a request from someone who ive done deals with before and asked for a favor and im making $0 on the build. Just cause your in bed with Leland now please dont make it look like Im doing something wrong. Im not commercial or making a business from my builds, I just like building stuff and trying new equipment.

as for wrong Let me know how am i wrong? I mean If you build a box bigger than speced size and add poly the poly makes it appear as the box is even bigger from everything ive ever read on box building. So depending on how much bigger the box is adding poly can cause it to xmax to be reached alot quicker with lower wattage to it correct? So if youre box isnt that much bigger than thats one thing but in general isnt my though process on this correct?
 
#729
hey, mcapote,

I'm simply saying if people are buying boxes from you, it behooves you to know what you are doing. If you don't, FOLLOW THE PLANS. That "bigger internal volume via stuffing" stuff went out a long time ago, and I just mentioned why the fill is REALLY there in my previous post. As I do on the website, probably (been so long since I wrote that I'm not sure how in depth I went).

The guys that are authorized are guys I know will do their best to be responsible to the customer, and understand what I've prioritized in the design, and have reputations for good work. It's not about who's in bed. In fact, those guys are really early risers, quick to get out into the shop ; }

EDIT: There are two more guys waiting in the wings to become authorized BUILDERS, pending a couple details. One will be listed on my website and is in S Cal, but the other prefers to deal only locally without distraction from further locales via TalkBass.
 
#730
well everything ive built has been to the plans except a couple handle changes that were requested. including the batting, but also the foam i was just saying remove the batting and put the foam in behind it. now that im re reading it I can see how it could of been mis understood. I just got a little upset about the AUTHORIZED in caps thing like i did something wrong. anyways the bigger internal volume thing seems alive and well in the car audio side because they all still talk about it all the time, and since i build both i read on both sides of the audio. Also iirc that GK guy was saying something similar too when we started adding batting to the MB combos
 
#731
mcapote said:
as for wrong Let me know how am i wrong? I mean If you build a box bigger than speced size and add poly the poly makes it appear as the box is even bigger from everything ive ever read on box building. So depending on how much bigger the box is adding poly can cause it to xmax to be reached alot quicker with lower wattage to it correct? So if youre box isnt that much bigger than thats one thing but in general isnt my though process on this correct?
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Just so you don't think it's only greenboy getting on you about it...You really HAVE TO put poly in the mid chamber. It has nothing to do with the myth of making a chamber "appear bigger". It has everything to do with taming some nasty mid reflections from getting back into and out through the speaker (and will do so, not in phase with what the speaker is putting out the front on it's own). It will sound MUCH better and with greater clarity.

And CLARITY is the main design character of a fEARful. If you don't put it in, you are doing a disservice to anyone you build one for, whether you make money, break even or lose money.
 
#733
Yeah, I did want to mention those handle changes again, mcapote. I've covered what things are priority items in the past several times and I think most have read at least one of them, but it's time to refresh the handles issue: Basically, unless someone puts a medium scoop handle on each side of a 12/6 which is relatively small, as well as another on top perhaps, what are on the plans are only suggestions based on easy tie-in to the bracing system, and the need some had for me to actually draw something on the plans.

...With smaller cabs it's wise not to take away much or add much volume internally by handle choice, but with larger cabs like the 15/6 I even inferred on its plan a couple of options, and removing or ading a handle or putting a top handle in won't jack with the tuning enough to even make a 1/4" difference in shelf length were one to desire matched tuning. So: non-issue basically, as cab gets larger. 12/6, tread a little lighter as far as big scoop handles.
 
#734
greenboy said:
Yeah, I did want to mention those handle changes again, mcapote. I've covered what things are priority items in the past several times and I think most have read at least one of them, but it's time to refresh the handles issue: Basically, unless someone puts a medium scoop handle on each side of a 12/6 which is relatively small, as well as another on top perhaps, what are on the plans are only suggestions based on easy tie-in to the bracing system, and the need some had for me to actually draw something on the plans.

...With smaller cabs it's wise not to take away much or add much volume internally by handle choice, but with larger cabs like the 15/6 I even inferred on its plan a couple of options, and removing or ading a handle or putting a top handle in won't jack with the tuning enough to even make a 1/4" difference in shelf length were one to desire matched tuning. So: non-issue basically, as cab gets larger. 12/6, tread a little lighter as far as big scoop handles.
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yeah ive actually also tried to adjust for the volume used by handles so internal volume actually stays the same. the 15/6/1 im building now the guy wants 3 handles 2 sides and a top though i suggested sticking with 2, but I havent gotten that far in yet since i was in the hospital for a couple weeks kinda killed my building :( hoping to get it up this weekend, since im back home and ready to route and glue
 
#735
im just stating what ive done in my past builds, incase anyone who now has one was wondering LOL. once this 15/6/1 is done and I may sell my last 15sub off to make room in my studio, I will probably be done building for a bit cause im dying to try out the BFM plans i bought a long time ago and left sitting in my harddrive LOL. and I got another person asking me to build a prototypeof his design which might turn into something else.
 
#736
greenboy said:
As far as the styrofoam chamber reduction, that is something else entirely. The 18 Sound midrange drivers use it in conjunction with the crossover component values to get a proper transition. It adjusts chamber Q to fit better. No damage results from not using the sty - it just doesn't work as well without it.
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So - where is this chamber reduction step stipulated to? Can this step be compensated for in the volume of the mid enclosure/chamber?

I am going to build out a miniDSP to biamp so I'm uncertain whether I need to consider this - no crossover is intended to be constructed unless I can be convinced it's necessary.

I have a 6ND410 fwiw . . .
 
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