Numbscull question on enclosure design

Bradrock

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#1
If I'm looking at a 12" woofer and the manufacturer recommends a 4 cubic foot sealed box, and I want to use two of them. Can I assume I want an 8 cubic foot box? Or is that not how it works?
I think I'll buy the BassBox software soon. But it's not at the top of my list, until I get going on the White Oak mods on my 3 amps.

Thank you for any guidance, Brad
 

Bradrock

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#3

Netfly

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#4
Thank you. I just used a round number for simplicity's sake. As I am a simpleton.
I know that I need to calculate in the mass of the drivers themselves & all bracing.
But not sure if it was as simple as doubling the size for two drivers, or if a special formula is required.
I appreciate you clearing that up for me.

Here are the woofs I'm considering:

https://www.madisoundspeakerstore.com/approx-12-woofers/sb-acoustics-sb34nrx75-6-12-woofer/
It's assumed that the speaker will be in the box. So you shouldn't have to calculate anything if there are no internal braces.

I'm not familiar with that brand. Things you need to decide - Are you running them as a stand alone sub or with passive crossovers to other speakers? 6Ω may be hard to mach to your top end speakers. Also can you amp handle 6Ω subs? What crossover frequency are you planning on? I would set that one at about 120hz. In general that speaker doesn't appear to have a very flat response.
 

Bradrock

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#5
I'm just starting the planning phase. This is going to take some time.
I plan to tri amp with one WOPL 700b & two WOPL 400's
Lot of work & time needed for me to get those modded.
I'm looking at Marchand electronic crossover systems & Lee has showed another groovy option he's going with.
I'm lucky to get a few minutes at a time away from caregiving my paralyzed wife, so this will be sort of a marathon project & plenty of time to change course.
I need to be careful not to wear out my welcome here over the month's, as I'd be lost without Phoenix.
 

laatsch55

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#6
I'm just starting the planning phase. This is going to take some time.
I plan to tri amp with one WOPL 700b & two WOPL 400's
Lot of work & time needed for me to get those modded.
I'm looking at Marchand electronic crossover systems & Lee has showed another groovy option he's going with.
I'm lucky to get a few minutes at a time away from caregiving my paralyzed wife, so this will be sort of a marathon project & plenty of time to change course.
I need to be careful not to wear out my welcome here over the month's, as I'd be lost without Phoenix.
Dude, just being here and asking questions, does not wear out your welcome. You're family now Bud.....
 

Bradrock

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#7
Dude, just being here and asking questions, does not wear out your welcome. You're family now Bud.....


Oh I know Lee & I'm very comfortable. It's just that when I let my fingers do my talking, things are not alway's received as intended. And believe it or not.....I can be a real jerk at times! Just ask my wife!!
I feel like I'm walking among giants here & I presume to know nothing. And assume I'll know much more as the weeks and months roll on & I learn me some tronics.


Rock on!
 

Netfly

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#8
I've been here a very short time too. So I don't want to be talking out of turn, but I like to help people with what little I know.
When it comes to picking parts, I'm not up on the latest and greatest stuff, but I do know a bit of theory. A Tri-amp with a 700B on the bottom is going to give you about 518w to each channel at 6Ω, before the WOPL mods which increase power. That's more than double what that 200w speaker can handle. So unless you want to wire four of them together for each channel, I'd pick a better speaker. If you're starting from scratch, maybe you should be thinking 15".
 

WOPL Sniffer

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I've been here a very short time too. So I don't want to be talking out of turn, but I like to help people with what little I know.
When it comes to picking parts, I'm not up on the latest and greatest stuff, but I do know a bit of theory. A Tri-amp with a 700B on the bottom is going to give you about 518w to each channel at 6Ω, before the WOPL mods which increase power. That's more than double what that 200w speaker can handle. So unless you want to wire four of them together for each channel, I'd pick a better speaker. If you're starting from scratch, maybe you should be thinking 15".
Do not "wire" 2 pairs of speakers together, it may cause serious problems for your amp. I run 110 watt speakers on my WOPL very often (all the time) and the power from the amp is so clean, you DON'T have to use the whole volume knob. Headroom is awesome on a WOPL. You wont have any issues with a 200 wpc set of speakers. I do agree with waiting and not wasting money on bonfire speakers. You get what you pay for...
 

WOPL Sniffer

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#10
There is a correct way to connect 2 sets of speakers together and it does NOT include twisting both positive to one post and both negatives to the other.
 

laatsch55

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#11
My K's are rated at 100 watts continuous........no shit.....they routinely take 200-300......
 

Netfly

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#12
You can run four speakers in a parallel, series configuration and get the same impedence of the 1 speaker, in this case 6Ω.
 

finebar4

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#14
Let me turn you on to the place I am considering picking up a pair of 15's from. Check out Accustic Elegance. He makes products for Infinite Baffle (2 in the ceiling using attic for "box"), open baffle (just a mounting face....no box), horn loaded, and conventional. I have heard a couple of his setups.....a friend of mine has 4 18's in his ceiling, and I have heard a pair of 12's each in a less than 2 cubic feet sealed in a suburban that with cabin gain.....rattled two fillings and a crown loose.

A word to the wise on power ratings on drivers. I have ran 100 watt drivers off a 300 watt amp all day. There isn't any issues a normal listening levels......it is when you crank up the juice that the issues begin. The ratings are based a lot on how much the voice coils can take. After a long jam session, you can smell the glue heating up on the coils and over time they will get brittle and break.....been there....burnt some :) you can hear the mechanical limits of a speaker real quick...but pushing thermal limits doesn't start coloring the music till it's too late. It's all in how you listen to your music..... if you like real loud...invest in higher efficiency drivers and speaker designs.....Lee's speakers could rock your world at 50 watts all day long......throw them a couple hundred watts and your ears are bleeding......but so worth it for the visceral effects!!!!
 
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Gepetto

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#15
You can run four speakers in a parallel, series configuration and get the same impedence of the 1 speaker, in this case 6Ω.
You can do this but that configuration kills the damping factor that the amp normally provides. Damping factor essentially is reduced to 1.
 
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