Buck Box Designs 2022 :)

[Buck 5,000+ posts]

Audio friend sent me this:

 

[sizmtrz]

Trying to fit 480 pounds of 12's with a combined 15,000w RMS rating in a blowthrough. It's such a tight fit, not sure if this will work yet or not:

View attachment 35660

View attachment 35661

Forgive my ignorance, when you aim speakers at one another does that create any cancelation? Like the air pressure from each side causing resistance on the movement of the adjacent speaker? thank you!

 

[metalheadjoe 10+ year member]

Audio friend sent me this:

View attachment 35673

Are those red critters subwoofers?

 

[metalheadjoe 10+ year member]

Forgive my ignorance, when you aim speakers at one another does that create any cancelation? Like the air pressure from each side causing resistance on the movement of the adjacent speaker? thank you!

When a subwoofer moves, it creates positive pressure on one side of the cone and negative pressure on the other side. Cancellation is when the negative pressure meets the positive pressure. Two subwoofers facing each other add to SPL the same way two subs in the same box do; they pressurize a common chamber in sync.

 

[Bobbytwonames 5,000+ posts]

Yes or No..
Did you have any part of these builds you posted in this thread?

Some of them. It's not my car audio shop. We all hang out at the shop like some people hang out at barber shops or bars. What's the difference? They are all real boxes and real builds. Did I ever say that I built these boxes and did the installs? Nope. Never. Do I help sometimes for free, yes.

 

[deez283 10+ year member]

Some of them. It's not my car audio shop. We all hang out at the shop like some people hang out at barber shops or bars. What's the difference? They are all real boxes and real builds. Did I ever say that I built these boxes and did the installs? Nope. Never. Do I help sometimes for free, yes.

I don't care either way.. I'm just wondering why it's so hard for a grown azz man to answer a simple question with a yes or no.. no need for a bunch of explaining and shit it's like talking to my kids.

 

[Buck 5,000+ posts]

I don't care either way.. I'm just wondering why it's so hard for a grown azz man to answer a simple question with a yes or no.. no need for a bunch of explaining and shit it's like talking to my kids.

Because he tries to act like they’re his builds, like he’s some huge part of this when really he just happens to be there. He wants to compare this stuff to my designs and I’m doing 100% of my designs from scratch and he’s taking pictures of someone’s else’s work and acting like we’re on the same level.

 

[Buck 5,000+ posts]

Forgive my ignorance, when you aim speakers at one another does that create any cancelation? Like the air pressure from each side causing resistance on the movement of the adjacent speaker? thank you!

Bass is pressure, so the only way woofers cancel is if they are out of phase with each other.

 

[mat3833 10+ year member]

Bass is pressure, so the only way woofers cancel is if they are out of phase with each other.

It's a little more complex than that when it comes to cancelation. Yes, sound is pressure. Yes, being out of phase will add a bunch of cancelation. But when you have sound waves interacting at angles weird things start to happen. You are definitely going to make pressure either way.

Totally not discrediting you man, you know so much more than I do about enclosure design and whatnot. But from my limited experience with multiple drivers interacting at angles narrower than 45 degrees, they have alot of odd peaks and dips across their range, but I'm speaking from more of a midbass/midrange perspective. Not sure how much of that translates to sub-60hz frequencies. It's really hard to model anything like this, hell I don't think there is a "consumer" level program for doing that even.

Matt

 

[Buck 5,000+ posts]

It's a little more complex than that when it comes to cancelation. Yes, sound is pressure. Yes, being out of phase will add a bunch of cancelation. But when you have sound waves interacting at angles weird things start to happen. You are definitely going to make pressure either way.

Totally not discrediting you man, you know so much more than I do about enclosure design and whatnot. But from my limited experience with multiple drivers interacting at angles narrower than 45 degrees, they have alot of odd peaks and dips across their range, but I'm speaking from more of a midbass/midrange perspective. Not sure how much of that translates to sub-60hz frequencies. It's really hard to model anything like this, hell I don't think there is a "consumer" level program for doing that even.

Matt

Well, bass is omnidirectional, so the pressure flow works differently with angles than midrange or highs. Mids and highs actually have a limited angles from main axis of propagation that produces sound. Bass isn't directional like a mid is. Highs are super directional, that's why you see people with tweeter pods. Subs are just frequency driven air pumps. If all of the subs are pumping together, then everything is all good, as long as they aren't too close together and have enough room to not have any specific part of the cone too pressurized.

You are correct, in a way, in that expanding-width chambers or ports are inherently more peaky, such as a horn will tend to be more peaky than a transmission line, and that's due how pressurization works in different volumes/cross-sectional areas at tuning frequency. A sub horn box, where the sub has very little line width at the throat, will resonate harder at tuning frequency than a t-line would, but the db/octave rolloff can be worse than a t-line, because if you're playing out of resonance with a horn, that tiny airspace at the throat doesn't provide much sound-boost, if the whole horn isn't loading.

If the whole horn doesn't load, that tiny airspace doesn't provide hardly any pressure to help make sound travel through the rest of the horn. But, if you have a t-line, the line width is consistent, which means the roll off away from tuning frequency will be more consistent. The amount of air behind the sub in a t-line allows the sub to move a lot more easily out of resonance, and there's more air to be pressurized immediately behind the sub, which then helps pressurize the whole line better across a wider bandwidth, and that's why t-lines are OG probably the best all-around enclosure for any type of music in any environment, IMO. I hope that made sense.

I stayed up late fighting that 6x 12's box and I'm just

 

[Buck 5,000+ posts]

I don't want to give away too much secret sauce here, but how much air is directly available to a sub to pressurize changes the nature of the enclosure.

I'll give an example: if you have 1 sub, and you have your port area and X amount of cubic feet. If you change the way X amount of sub-loading-air travels to the port through the loading chamber, you can guarantee the sub is using all of the box's chamber-loading potential. But be careful- in ported boxes, you don't want hinder flow within the chamber itself. I've seen this with bracing, where too much bracing will divide a sub's loading chamber in half, and the air from the sub faces too much resistance trying to pass through the bracing to make it's way to the port.

I've been doing this a minute

 

[SlugButter]

I did some very unscientific testing with some clamshell designs a long time ago and the clamshells seemed a little bit louder I think. I used 4 10 inch JL w3 s. I did 3 builds for testing. I staggered the subs and did a normal flat baffle and I did a 90 degree and an approx 120 degree angle on the clamshells. The 120 wasn’t an exact angle and I don’t remember what it actually came out to. I did it by trial and error measuring/cutting and angled it the least amount I could and still be able fit 4 10 inch subs into a 36 inch wide space. The 90 degree one seemed louder to my ear than the normal baffle. It could’ve been psychological though. I wish I would have had a meter to actually test it.

 

[mat3833 10+ year member]

I did some very unscientific testing with some clamshell designs a long time ago and the clamshells seemed a little bit louder I think. I used 4 10 inch JL w3 s. I did 3 builds for testing. I staggered the subs and did a normal flat baffle and I did a 90 degree and an approx 120 degree angle on the clamshells. The 120 wasn’t an exact angle and I don’t remember what it actually came out to. I did it by trial and error measuring/cutting and angled it the least amount I could and still be able fit 4 10 inch subs into a 36 inch wide space. The 90 degree one seemed louder to my ear than the normal baffle. It could’ve been psychological though. I wish I would have had a meter to actually test it.

The clamshell opening itself should act kinda like a horn in reality. But as you move from the port opening in the back towards the front you have the woofers compressing the air in the clamshell even further. It's alot of energy being put into a small "cone" of air inside the clamshell.

Louder? I would almost bet money on it. But you are probably loosing some efficiency with the drivers compressing already compressed air. A wider clamshell angel would probably be better from an efficiency standpoint.

Keep in mind, I'm one or 2 steps above talking out my ***. I can say that mounting the baffle in my current setup at the factory back seat angle(some thing like 30 degree recline) was definitely louder to the ear than having it at an actual 90 degrees up and down.

There's a reason horns are used almost exclusively in large venue applications. They are crazy efficient and self-load when designed properly. They will be just as loud in an open field as inside a room.

Matt

 

[Buck 5,000+ posts]

The clamshell opening itself should act kinda like a horn in reality. But as you move from the port opening in the back towards the front you have the woofers compressing the air in the clamshell even further. It's alot of energy being put into a small "cone" of air inside the clamshell.

Louder? I would almost bet money on it. But you are probably loosing some efficiency with the drivers compressing already compressed air. A wider clamshell angel would probably be better from an efficiency standpoint.

Keep in mind, I'm one or 2 steps above talking out my ***. I can say that mounting the baffle in my current setup at the factory back seat angle(some thing like 30 degree recline) was definitely louder to the ear than having it at an actual 90 degrees up and down.

There's a reason horns are used almost exclusively in large venue applications. They are crazy efficient and self-load when designed properly. They will be just as loud in an open field as inside a room.

Matt

This is a thoughtful post.

I think you only lose efficiency if your chamshell is too small for the power + cone area. Some woofers now have so much motor force that you can get away with tighter distances or more extreme proximities, to a degree. It's all relative and situation by situation.

Clamshells do have horn-like properties and are more efficient, in general. In a car audio application with a really big system, say a full wall clam, that style can really have some benefits. The depth of the clam and the angle are huge factors. Basically a clamshell becomes a series 6th order when the opening mouth into the environment becomes smaller than the rest of the line.

You can take a ported flat wall, let's say for 4 15's with a center slot port, and fold it into a clamshell, then keep folding it, and it becomes a series 6th order just after the 2 clam halves are parallel to each other. I guess it's like a -clam angle lol

 

[sizmtrz]

When a subwoofer moves, it creates positive pressure on one side of the cone and negative pressure on the other side. Cancellation is when the negative pressure meets the positive pressure. Two subwoofers facing each other add to SPL the same way two subs in the same box do; they pressurize a common chamber in sync.

Thank you!