Need box design plans for mojo 12s

[Buck 5,000+ posts]

and if you're listening to rap, i would tune at 32-34. like if you want musical bass, you can do closer to 10-12 in^2 per cube. you may want to download winisd or something, to see what your port air speeds look like.

But i wouldn't go too small without absolutely checking airspeed first.

 

[LMJexploder]

Ok I'll check and see what the numbers are thanks you want the air speed to be under like 15ish right

 

[Buck 5,000+ posts]

Ok I'll check and see what the numbers are thanks you want the air speed to be under like 15ish right

no no. absolute maxiumum air speed is about 54 m/s or .16 mach. I have really good results with 30-35 m/s for daily. Expecially with 4th order. I don't like much under 20 m/s or so for ported boxes. But it depends on the woofer and basically how stiff the suspension is. People give WAAAAYYYY too much port area for 4th orders for some strange reason. I've done a lot of 1000w-1500w per woofer 4th order bandpasses that use 12in^2 per cube, like the older 1250w sundown x 15's.

You really have to keep in mind that t/s parameters + box designing programs =/ real world sound. Air speed can be way off, is what I'm saying. If you ever get to design over 1000+ individual boxes, you can recognize when t/s parameters are doodoo. Subwoofer box programs also sometimes have issues with woofers with progressive suspensions. You can have a relatively high Vas, reltatively low Fs (mid 20's to low 30's), AND low Q factors with a progressive woofer, and I've found that sometimes programs don't know wtf to think about that. My old Fi Bl 18's were like that. They modeled horribly. But they were stupid loud. So you gotta kind of see through the haze of some of this stuff.

 

[Buck 5,000+ posts]

Don't take offense OP, I am really not a fan of memphis woofers. When I worked at a shop and had my 2 dc xl 18's, I gave our local memphis rep a demo. He was like holy f*ck, I want you to use our products and be a rep. I told him no. We were dealers for Sundown, DD, CT sounds. idk if CT still has all those prefab box designs i did for them up or not. I did probably 20-30 designs or something for the owner, i forget his name, so he could put them up for free on the website back in 2018 i think. Companies like Sundown and DD and SQ and DC and SSA and Fi are the real woofer pros.

Memphis takes some short cuts, like having to have a 3.5" VC instead of like doing actual proper cooling. If you have that large of a voice coil and only a 235 oz motor,, it's a sign to me of cheapness in the actual designing phase. So you wind up with this huge Mms. It makes the woofer moving parts very heavy.

 

[Buck 5,000+ posts]

Product Page | memphisaudio

www.memphiscaraudio.com

 

[Buck 5,000+ posts]

So these 12's have a Mms of 400 grams which is heavy for a 12. Weak motor it looks like, so you're going to lose so much sound trying to move that heavy *** coil with that weak *** motor.

edit: i shouldn't say the motor is weak because i don't know the Re it was measured at, if it was series or parallel with the VC's

 

[Buck 5,000+ posts]

And those pretty high q values come from all of that extra weight more than likely.

 

[Buck 5,000+ posts]

The Qms is alright. But look at how high that Qes is. That's combo of that big VC and heavy Mms. So if you look at say an Fi SSD @ 1500 watts, you can compare some.

SSD v4 Series | Fi Car Audio

ficaraudio.com

 

[Buck 5,000+ posts]

You see the Mms of the SSD is only 313 grams, and the Q values look much lower and the BL is significantly higher. And that's all because of the way memphis cheaps out on their motor design. There is absolutely no need for a 3.5 vc for a 1500w woofer IMO.

 

[Buck 5,000+ posts]

Another thing about their motor design that i think i've seen in the past is they have large gaps in the motor where the voice coil moves in and out of the motor. Those larger gaps keep the woofer cooler, but you get a weaker magentic field concentration in the gap for the coil. So the coil doesn't have as much magnetism to push and pull itself around. I know Orion does this too, with the big VC's and larger motor gaps. Sundown does a really good job with their motors, for example. They use some of those neo shorting rings, and they extend the center pole like up into the center of the voice coil for more magnetic grip, if you will. And you look at the gaps that the coil fits in, they're way tighter, because Sundown puts a lot of work and cooling and magnetic design into their woofers. Many other companies do this too.

 

[LMJexploder]

It's all good no offense taken I got um for basically nothing anyway so if they don't work out I'll stick with my type Rs untill I get something else to try I was looking at some dc subs any recommendations

 

[Buck 5,000+ posts]

It's all good no offense taken I got um for basically nothing anyway so if they don't work out I'll stick with my type Rs untill I get something else to try I was looking at some dc subs any recommendations

My 2 DC's were my favorite subs i ever owned. I may be able to get you some. PM me if you're interested. Let me see if an old connect I have works. I've designed A LOT of DC boxes. People used to make fun of DC and say it stands for Direct Copy (referring to Digital Designs iirc). But DC's are really good woofers and I think they have a style of their own. Their smaller box sizes are really appealing. Before I moved to FL, I did a DC level 3 for my local buddy in his nissan. I'm sickly and poor and we wound up cutting the box on one of his friend's parents back porch like on one of their patio tables LOL

But we built the box, like 3.5 cubes @ 33 hz or something. I sold him my worse-condition ed 9.1 man, and I was surprised. That 9.1 is too much power for that sub, but I set the gains for him. It was loud and sounded so good.

I had another guy when i was building boxes, he was competing with a mazda rx-8, like the only car worse for competing than that would be a miata or something. But we did a trunk passthrough box. I think they were level 4 Xl 10's. But he did like a 147 @ 35 hz in that rx-8 with ONE 50 ah battery and a 3800w amp. Underpowered the woofers and literally like no electrical at all. Idk how he didn't fry that amp. I couldn't believe he did a 147. FYI when you do a ported box like this, it starts acting more and more like a series 6th.

But I've just generally been impressed with DC's when I was doing audio. It's been a couple of years but it looks like they're still good as always.

 

[Buck 5,000+ posts]

My 2 DC's were my favorite subs i ever owned. I may be able to get you some. PM me if you're interested. Let me see if an old connect I have works. I've designed A LOT of DC boxes. People used to make fun of DC and say it stands for Direct Copy (referring to Digital Designs iirc). But DC's are really good woofers and I think they have a style of their own. Their smaller box sizes are really appealing. Before I moved to FL, I did a DC level 3 for my local buddy in his nission. I'm sickly and poor and we wound up cutting the box on one of his friend's parents back porch like on one of their patio tables LOL

But we built the box, like 3.5 cubes @ 33 hz or something. I sold him my worse-condition ed 9.1 man, and I was surprised. That 9.1 is too much power for that sub, but I set the gains for him. It was loud and sounded so good.

I had another guy when i was building boxes, he was competing with a mazda rx-8, like the only car worse for competing than that would be a miata or something. But we did a trunk passthrough box. I think they were level 4 Xl 10's. But he did like a 147 @ 35 hz in that rx-8 with ONE 50 ah battery and a 3800w amp. Underpowered the woofers and literally like no electrical at all. Idk how he didn't fry that amp. I couldn't believe he did a 147. FYI when you do a ported box like this, it start acting more and more like a series 6th.

But I've just generally been impressed with DC's when I was doing audio. It's been a couple of years but it looks like they're still good as always.

I do not use the name High Output Enclosures. My buddy took that name when I quit working with him. Here's his site I believe. I'm actually in one of these videos: https://soundauthority.co/

 

[Buck 5,000+ posts]

I'll show you my DC box. It was originally for 2 400 watt CT sounds 18's, but my DC XL's fit in it.

 

[Buck 5,000+ posts]

If you're going to do your box yourself, winisd pro can really help with things like vent speed, and even sometimes you can look at xmax if you're worried about a woofer or a design that might bottom out a woofer. Only other free one worth a crap is bass box pro 6 iirc, but it's a PITA to use. But it lets you do series 6th orders and stuff, even though i never modeled a series 6th order once in my life besides just checking ports. series 6th rear ports are a ***** to get perfect.

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