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View Full Version : review and correct my porting tutorial please



req
01-07-2005, 02:58 PM
for all those out there who know exactally how to create the port and the box to go with it, could you read over this, and tell me if anything is wrong, or sounds funny.

constructive critism only please. im trying to explain it in LAMENS terms, so that people will actually understand it.

please no flaming if somthing is wrong, just try and correct it.

thanks.

www.asterixband.com/req/port.htm

95RAM
01-07-2005, 03:30 PM
im really liking the site although have no knowledge of ports.

req
01-07-2005, 03:37 PM
sigh. well, hopefully somone will take a look and let me know if its correct, and if its not, they can point out what is wrong.

Nikuk
01-07-2005, 03:57 PM
can't...

check.......

spam...........

ing...................

req
01-07-2005, 04:04 PM
can't...

check.......

spam...........

ing...................

eh? you are eating spam?

why cant you check?

spam tastes good with macceroni and cheese. :fart:

Nikuk
01-07-2005, 04:09 PM
spam = whoring

req
01-07-2005, 04:13 PM
spam = pork byproduct.

but seriously. im not trying to whor3 anything nj... im trying to write an article that people understand, and you are always helping people with their ports and whatnot, so i figured you knew it like the back of your hand. i dont see what the problem is dude. just trying to get alot of info together in one place, that is correct.

if you dont wanna help. then dont. but thanks for replying. :popcorn:

DFW40
01-07-2005, 04:15 PM
I liked it and thought it did a good job of getting the basics out there. I guess you could go deeper into the benefits of tuning low vs high and why SPL is tuned higher and why a lower tuned box is known more for SQ than the higher tuned boxes and what happens to the air pressure at tuning etc but that is more acoustics and sound wave tech jargon than what might be needed.
Great job

req
01-07-2005, 04:16 PM
I liked it and thought it did a good job of getting the basics out there. I guess you could go deeper into the benefits of tuning low vs high and why SPL is tuned higher and why a lower tuned box is known more for SQ than the higher tuned boxes and what happens to the air pressure at tuning etc but that is more acoustics and sound wave tech jargon than what might be needed.
Great job

thanks man. i could have sworn i missed part somewhere though. but i cant figure out where.

i may go deeper into *why* you should tune low, but ill write that in a seperate article so that they dont get off track when learning how to do it, ya know?

Nikuk
01-07-2005, 04:17 PM
spam = pork byproduct.

but seriously. im not trying to whor3 anything nj... im trying to write an article that people understand, and you are always helping people with their ports and whatnot, so i figured you knew it like the back of your hand. i dont see what the problem is dude. just trying to get alot of info together in one place, that is correct.

if you dont wanna help. then dont. but thanks for replying. :popcorn:


no, no, no.... not you!

I'm spamming right now.... will check later. :stuck:

req
01-07-2005, 04:19 PM
no, no, no.... not you!

I'm spamming right now.... will check later. :stuck:


oooooooh. i thought you meant I was spamming :nerd:

thanks :p:

and you do know, that i wasnt being rude. just want to get it all straightened out, and a complete and understandable tutorial :)

thanks nj :patrioti:

Damaso87
01-07-2005, 08:44 PM
I dont like the crosshair cursor...

req
01-08-2005, 11:34 AM
sigh :(

Nikuk
01-08-2005, 01:03 PM
Fs - the tuning frequency of the box or port - measured in square inches, in^2 FS is not measured in sq in.
Vb - the enclosures net volume - (length x base x height) measured in eaither cubic inches or cubic feet, in^3 or ft^3 Net volume should be explained as internal measurement after all displacements. -and- what about measuring in Liters...?
Lv - the linear (down the middle) length of the port - measured in inches - in Explain about measureing through turns (L & "Labyrinth" Ports grow long very fast because of this).
Av - the cross-sectional area (port mouth) of the port - (base x height) measured in square inches, in^2 What about Pi*R^2?

On your box diagram you didn't account for the (3/4"?) width of Port Board 1 when you 'measured' "Y." -and- It looks like "X" only measure to the interior of the baffle. It should measure right to the atmosphere (outside).

When I click onthe "Port Calculator" link the result is:

404 Error Page
The page cannot be found
The page you are looking for might have been removed, had its name changed, or is temporarily unavailable


No offense, I would Just feel that If I'm putting up a public page I would try to have it all as close to perfect as I could get it.

Hope this all helps.


-Nick

req
01-08-2005, 04:05 PM
thats why its not public yet. its not linked via the main page, i only posted it in here so far :)

ill add\change all that stuff, and let ya know. but basically, its correct (aside from points listed above)?

ill get it all done on mondy hopefully.

off to go snowboarding :D

thanks nick!

Nikuk
01-08-2005, 04:49 PM
thats why its not public yet. its not linked via the main page, i only posted it in here so far :)

ill add\change all that stuff, and let ya know. but basically, its correct (aside from points listed above)?

ill get it all done on mondy hopefully.

off to go snowboarding :D

thanks nick!

Nope, I didnt see anything else thats really off. Again, I didnt try out your actual calculator though.

Be safe.

req
01-09-2005, 11:38 PM
lol, be safe :P

ill update it tomrrow when i get back to work (backuing up the system. gotta burn mad discs and have free time while im doing it)

ill let you know, thanks a ton nick.

8inw7
01-10-2005, 12:14 AM
Hey, dont most people tune their subss to like 65 hz or somethin? Why so low?

Nikuk
01-10-2005, 11:05 AM
Hey, dont most people tune their subss to like 65 hz or somethin? Why so low?

Depends on the driver and the owner.

For daily, you usually want a lower tuning to acheive a flatter respone.

DFW40
01-10-2005, 12:00 PM
I think that he might have meant to say 65hz was a crossover point not tuning?

Nikuk
01-10-2005, 12:03 PM
I think that he might have meant to say 65hz was a crossover point not tuning?

yes, possible. But I generally pass subbass <65hz also.

req
01-10-2005, 12:07 PM
sorry for not updating nick, but im going home eairly because i think i have tonsilitis and im going to a dr appt.

ill try and get it set up at my house so i can fix it there.

Nikuk
01-10-2005, 12:13 PM
sorry for not updating nick, but im going home eairly because i think i have tonsilitis and im going to a dr appt.

ill try and get it set up at my house so i can fix it there.

Bro, if you're feeling ill... don't even worry about this place. LoL...

Internet forums & help < Getting better. IMO.

I'm not going anywhere.. :thumbupw:

-Nick

8inw7
01-10-2005, 04:08 PM
I think that he might have meant to say 65hz was a crossover point not tuning?


Well i obviously dont know what im talking about. I thought tuning meant that the stated frequency was the highest possible frequency the sub plays. I looked up crossover point and i understand that to be the point where all frequencies above a point go to like your rear speakers n all below a point go to your sub. I guess i did mean a crossover point.

Now i must ask what is tuning? Why do you tune to certain frequencies? How do you tune to certain frequencies?

req
01-11-2005, 12:32 AM
can you take this one nick? im going to bed and i feel ike *** :p:

ill try and get some updates someday *sigh*

sumone
01-11-2005, 04:17 AM
tuning = optimizing a sub's frequency response curve in order to manipulate a peak in SPL around that frequency. However, below that frequency, you don't wanna mess with. So that's why a little below your tuning frequency is the lowest frequencies you'd get some good output from, and below that, it could get crazy; therefore a highpass should be somewhere near your tuning frequency.

you tune to certain frequencies cause...umm....certain frequencies have certain sounds??? If you've ever listened to sine waves of different frequencies, you'll know what I mean. For example, SPL is associated with the 50s & 60s hertz ranges. 30s and below gives that real low "sub-bass". may be a stupid analogy, but say the 50s & 60s range can be considered a slim fast guy...say bruce lee, punching you in your chest, while the 30s can be considered a big guy like the incredible hulk punching you in your chest. ah, I don't know...dumb analogy

you tune to certain frequencies by routing the back wave from the subwoofer out of the box. the route & length that the back wave takes to exit the box is mathematically correlated to the tuning frequency, area of the port, & volume of the box w/o the port.

sumone
01-11-2005, 04:20 AM
Bro, if you're feeling ill... don't even worry about this place. LoL...

Internet forums & help < Getting better. IMO.

x2 man...I know someone who just passed....from the **** flu...so get your health

also, Fs...the resonant frequency is also called Fb....

and another thing, the port length should account for end correction, which is the port_width / 2. So that physical length of the port is actually Lv - port_width/2 instead of just Lv.

req
01-21-2005, 02:34 PM
FS is not measured in sq in. Net volume should be explained as internal measurement after all displacements. -and- what about measuring in Liters...? Explain about measureing through turns (L & "Labyrinth" Ports grow long very fast because of this). What about Pi*R^2?

On your box diagram you didn't account for the (3/4"?) width of Port Board 1 when you 'measured' "Y." -and- It looks like "X" only measure to the interior of the baffle. It should measure right to the atmosphere (outside).

When I click onthe "Port Calculator" link the result is:
bla bla bla
-Nick

k i got everything cept the port board 1 part and the labyrinth port part. i am not posative what the difference is between a labrynth and a slot, cept that since it folds there is more pressure or somthing and you have to compensate for this by making it longer? like i sad, i dunno :p: but im trying to get it all in there. mind copy\paste the text from the site and chaning it or describing a little better what you mean?

sorry it took so long. i think im going home eairly. :crap:

req
01-21-2005, 09:48 PM
bump?

nick whered ya go?

Nikuk
01-21-2005, 10:00 PM
whasssup?

req
01-23-2005, 10:56 PM
post # 28?

im not too sure on those two things you were talkin about...


Explain about measureing through turns (L & "Labyrinth" Ports grow long very fast because of this). What about Pi*R^2?

On your box diagram you didn't account for the (3/4"?) width of Port Board 1 when you 'measured' "Y." -and- It looks like "X" only measure to the interior of the baffle. It should measure right to the atmosphere (outside).

mind explaining those?

mykeys
01-24-2005, 09:35 AM
I am not the greatest at explaining things, so I will try to be brief. While reading you wrote the the port opening (mouth) should be half the area of the sub. Though it looked more like you meant the over all port volume in the pics and then more or less backed that idea as you continued your tutorial. I think some rewording may make it easier especially for a noobie. In my designs and even some of the MFG specs the port mouth has been close to 1/3 of the overall surface area of the sub which leaves the port several inches longer than the sub and keeps the air pressure low enough not to need worrying over port noise caused by too small of a port..

I hope that said what I mean since I have barely finished a cup of coffee this morning.

Mike

req
01-24-2005, 11:28 AM
thanks, ill edit that part too.

i know that it *can* be smaller than 1\2 of the area and still have no port noise, espically when the power is lower - say 200~500w and the air isnt flowing thru real hard.

ill put it in there and explain why you want a bigger port if possible, but if not, it can be smaller.

should i say that the port should always be around a ratio of 8:1 as well?

bcarpenterfhl
01-24-2005, 12:34 PM
the best way to see where your tutorial neeeds improvement is to have someone inexperienced with box building and design try it.