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View Full Version : slot vs aero AGAIN!!



jusBloud
12-05-2009, 01:54 PM
has anyone testet the same exact set up slot vs areo? I have a trunk car and i'm gonna try sub back but i'm wondering if i shoud try slot or aero. the first aero box i made didn't live up to the hype but i only had a 8 inch areo for 4.7 ft. what size aero would be good in that size box?

azimuth
12-05-2009, 01:57 PM
was it an actual aero, or just a round port?

jusBloud
12-05-2009, 02:03 PM
was it an actual aero, or just a round port?

round port

MakeshiftAudio
12-05-2009, 02:06 PM
Eh, the only difference is the presence of flaring.

azimuth
12-05-2009, 02:07 PM
agreed. you had far too little port area without flared ports.

jusBloud
12-05-2009, 02:22 PM
agreed. you had far too little port area without flared ports.

10 inch tube?

jusBloud
12-05-2009, 02:24 PM
2 6's? the 10 would be extremely long and i have no idea where to find a elbow that big

Ray21
12-05-2009, 02:28 PM
If you're not going to use flared round ports (aeroports/precision ports), then just make a slot ported box with the appropriate amount of port area.

Simple round ports without flares give no real benefit over properly designed slot ports.

mazdakid
12-05-2009, 02:30 PM
an 8" round wouldnt be too bad

MakeshiftAudio
12-05-2009, 02:46 PM
I just used a large band saw and cut my 10" PVC port at a 45 to make an elbow. I am considering machining a jig with an internal heater to flare them to see if I notice a difference.

SicAudio
12-05-2009, 02:47 PM
8" gives 10.68 sq in per cube so depending on the sub / s it shouldnt have been horrible.
i still prefer slot ports the slot acts as a brace for the box. i think aeros are all look and hype personally especially for what they cost but thats just my .02 . if they could be proven to me to increase sq or db by a significant amount then I would change my mind.

Ray21
12-05-2009, 02:51 PM
Flared round ports decrease port velocity, performing as if they had more cross-sectional area.

There's a thread somewhere saying that they are so efficient, you can get away with half the port area by using flared round ports.

MakeshiftAudio
12-05-2009, 02:51 PM
The reason I use it is due to size constraints and simplicity. An external aero port is easy to calculate for tuning, and can worm through weird spaces in an attempt to achieve optimal box volume, port area, and port length. :)

basebalz13
12-05-2009, 02:53 PM
slot port if your not using true aero port

Plottin4success
12-05-2009, 02:54 PM
I bought Aeros bc someone told me it would make my ***** bigger.

I sold them shortly after.

Skip01
12-05-2009, 02:57 PM
You can make a box sooooo much smaller, externally , with aeros.

Its almost impossible too do side by side test really.

Cabin_Pressure
12-05-2009, 02:58 PM
Title FAIL! A piece of PVC is not an aero-port.

jusBloud
12-05-2009, 03:04 PM
i think i'm more lost now than when i started

Ray21
12-05-2009, 03:16 PM
i think i'm more lost now than when i started

Read this:
http://www.caraudio.com/forum/showthread.php?t=412621

robertoyoung08
12-05-2009, 03:23 PM
The reason I use it is due to size constraints and simplicity. An external aero port is easy to calculate for tuning, and can worm through weird spaces in an attempt to achieve optimal box volume, port area, and port length. :)

can you figure out aero "math" calculations easily then?

i REALLY need some help figuring out some aeros length/diamater.

amartin_72
12-05-2009, 03:29 PM
This box is 4.5 ft 8" aero and its one of the 10 best sounding subs i've heard. Hatchbacks are amazing.

Its on an AQ 1200D we clamped it at 1000watts D2 wired parallell 1 ohm rising to 2.6 ohms! sometimes 3!

http://audible-engineering.com/jery001.jpg

video

http://s37.photobucket.com/albums/e76/amartin_72/?action=view&current=jery008.flv

http://s37.photobucket.com/albums/e76/amartin_72/?action=view&current=jery008.flv

jusBloud
12-05-2009, 03:40 PM
This box is 4.5 ft 8" aero and its one of the 10 best sounding subs i've heard. Hatchbacks are amazing.

Its on an AQ 1200D we clamped it at 1000watts D2 wired parallell 1 ohm rising to 2.6 ohms! sometimes 3!

http://audible-engineering.com/jery001.jpg

video

http://s37.photobucket.com/albums/e76/amartin_72/?action=view&current=jery008.flv

http://s37.photobucket.com/albums/e76/amartin_72/?action=view&current=jery008.flv
the size of the box is the only thing that matters for port size right? cause i had 3 10's in mine.

amartin_72
12-05-2009, 03:43 PM
No I believe to choose port area you have to factor in total power and xmax, cone area, what the sub likes. Thats what I do it works great every time. If This box was for 3kw I might do even more port area like two 6's. But more port area usually brings down SQ. Depends what you like.

amartin_72
12-05-2009, 03:45 PM
Like A box for two 10" HDC3's would need 14-15 sq inches of aero per cube,8" in 3 cubes but if it was for say two concepts getting 250 rms, 2.8 cubes and 6" aero would be fine. When you have aq's in the big port area boxes they do sound different at low to mid volume but when you get them going they sound great, very powerful. If you dont want that sound at low volume then cut the port area down and it will help over all SQ - to a point.

RAM_Designs
12-05-2009, 03:46 PM
the size of the box is the only thing that matters for port size right? cause i had 3 10's in mine.

Things that determind port length.
1) box size
2) tuning frequency
3) size of the port
4) number of ports

amartin_72
12-05-2009, 03:55 PM
There are so many industries that have used flared and contoured edges to flow things 2x - 3x what they could before they implemented the technology. Inside the tips of diesel injectors each of the spray holes on the nozzle have flared edges internally to get more flow through a smaller hole. They do this by drilling the holes in the nozzle (about .035 inch drill bit i think) and then pumping silly putty with diamond dust through the nozzle wearing down the edges of each hole.

jusBloud
12-05-2009, 04:06 PM
Things that determind port length.
1) box size
2) tuning frequency
3) size of the port
4) number of ports

let me re word that! does the amount of cone area count at all?

Lakota
12-06-2009, 06:38 PM
Which is best depends on the box design. Some boxes are louder slotted (like walls) and most street boxes are louder with aeroports. It really depends on the the application.

sub-FATHER
12-06-2009, 06:54 PM
i think i'm more lost now than when i started

thats because your taking advise from makeshift audio on box building. that guy fixes amps.

what kinda subs are you running? because the best designs ive seen and heard is with the subs firing foward and completely sealing off the trunk from the cabin. with a slot port on the driver side firing foward.

jusBloud
12-07-2009, 08:38 AM
thats because your taking advise from makeshift audio on box building. that guy fixes amps.

what kinda subs are you running? because the best designs ive seen and heard is with the subs firing foward and completely sealing off the trunk from the cabin. with a slot port on the driver side firing foward.

http://www.caraudio.com/forum/showthread.php?t=443516

i got a 2000 watt amp.cut the port and it does sound better. but i think i need a bigger box. i'm gonna try 2 in 4.5. what size round port? 2 6's? make a elbow for a 10?

BassMechkanic
12-07-2009, 10:22 AM
This box is 4.5 ft 8" aero and its one of the 10 best sounding subs i've heard. Hatchbacks are amazing.

Its on an AQ 1200D we clamped it at 1000watts D2 wired parallell 1 ohm rising to 2.6 ohms! sometimes 3!

http://audible-engineering.com/jery001.jpg

video

http://s37.photobucket.com/albums/e76/amartin_72/?action=view&current=jery008.flv

http://s37.photobucket.com/albums/e76/amartin_72/?action=view&current=jery008.flv



where do you fins aeros's that size? or do you make them?

amartin_72
12-16-2009, 02:29 PM
www.audible-engineering.com

RCobra07
12-18-2009, 12:40 AM
This box is 4.5 ft 8" aero and its one of the 10 best sounding subs i've heard. Hatchbacks are amazing.

Its on an AQ 1200D we clamped it at 1000watts D2 wired parallell 1 ohm rising to 2.6 ohms! sometimes 3!

http://audible-engineering.com/jery001.jpg

video

http://s37.photobucket.com/albums/e76/amartin_72/?action=view&current=jery008.flv

http://s37.photobucket.com/albums/e76/amartin_72/?action=view&current=jery008.flv


How on earth is it rising by 1.6-2.0 ohms?? I can not understand this for the life of me...is there anyway to estimate for this?

mylows10
12-18-2009, 02:30 AM
i tried both slot and aero ports in my box, same frequency but louder by almost 3 db with the areo ports

amartin_72
12-18-2009, 02:36 AM
I dont know why it was rising that much, combination of heat and box rise. That was after beating it for a few hours.

SicAudio
12-18-2009, 02:50 AM
WARNING: BORING SCIENCE AHEAD!!

It should allow the back wave to travel freely to the outside environment to add to the front wave. A ported enclosure is what is known as a Helmholtz resonator. What a HR is is a cavity of air with a neck or channel at one end. When the pressure inside the cavity is increased, the air wants to go to the area of lower pressure, aka, the outside, so that it is in equilibrium. Now, think about your speaker cone as a spring: as it moves in, it compresses the air in the box which increases the air pressure inside the box compared to the outside.

Unfortunately, when the compressed air inside the cavity encounters the internal mouth of the port, the air will have momentum to it and the cavity will consequently overcompensate for this and push out too much air. Why does it have momentum? The air in the cavity is of a much greater volume than the air in the port and by fluid dynamics, to account for the difference in pressure, the air in the narrower channel must move faster than the air in the box is actually being pressurized. That's also why smaller ports have higher port velocity: the air in the port has higher momentum which as you may know is a function of velocity, or as we are concerned, acceleration since the force that the cone is exerting on the air is changing due to excursion and different frequencies.

Now that the pressure in the box is too low, the speaker needs to **** in more air to be at equilibrium again. The process can repeat in reverse again and again until you get to equilibrium. That's why when you put a plastic bag in the port of your sub box to show off, it doesn't get ****** into the port, rather, it just flaps around. Air is being forced out and forced in succession.

This is the same reason why you cannot use too large of a port for a given volume because the speaker will not pressurize the chamber and will instead just shoot the air out the port acting like a horribly designed transmission line.

This is also why different speakers need different sized enclosures or not to be ported at all: if they cannot return that box to equilibrium (speakers with a high Qts value) quickly, the bass will be sloppy and the speaker can get out of control. A speaker that can create more pressure in the box is likely going to need a larger enclosure (larger diameter cone, or higher excursion) versus one that is smaller or moves less.

How does this pertain to slot and aero ports? An aero port allows the air to flow out of the enclosure more freely than does the slot port due to causing less turbulence, thus allowing for freer air flow for a given port area. That lets you get away with a smaller diameter port as he said, but the air is not being compressed better, rather, it's flowing more efficiently which is exactly the opposite. Unflared ports have little to no advantage.

Hopefully that helped you understand a bit about how ported boxes work and why you can't just throw any sub into a ported box and expect it to be loud.


dave

pv audio from a dif thread.

PioneerSPL1990
12-18-2009, 03:11 AM
round w/o flare are easiest to build.

CoequeCrype
12-21-2009, 08:59 AM
I dont remember if it was in this forum or in another one but someone they were waiting for another Mclaren car even posted a part number CA010D. Granted car numbers go in order abc... but could they have had info on a new car. I will try and find the post.