If you wanna know what LENGTH your port should have, check out: "What is the best Port length?" ukposts.info/have/v-deo/inR2eaNkgY1oypc.html

Finally the youtube algorithm suggest something i WANT to see

I only watched a few of your videos yet, but so far i love them. I love how u break things down and go into depth on subjects. It really has taught me alot. Keep the videos comming and I will keep watching. Thanks for all the advice.

Finally something I actually want to watch.. Thank you

Below the tuning frequency, ported system acts like open back enclosure. To maintain some back pressure on the driver I find keeping port area to be 1/4 to 1/8 of the driver cone area works the best. Of course there're systems like Altec A7 where port is much bigger than the driver ( but driver has reasonably stiff suspension that supports the driver cone )

ported enclosure sounds good on bigger speakers but I always like the passive radiators in motion also it only need less box size.

This video is infinitely easier to follow than the others. Thanks!

i would like to see experimentation with adjustable port size to demonstrate it, with various musics and tones. Great Video, and thank you kindly.🌺

Found this video while trying to tune the port on my 2x10 Ampeg (copy) bass cabinet, 50L. Did the math, it sounds spot on. Thanks!

The information here has been proven over and over and never fails. I’ve seen videos of these kids with these new subs with higher power and they think they need a bigger port.

Long live the BOSS,finally I got what I need,god bless u

Thanks dude, this was incredibly informative, like most of your vids ofc!!

I've been doing alot of wondering about my port size I built my box with a tuned to 35/36 with 129.5ci port area (7"x18.5") for 2 American Bass XR15s on a 2k amp, the box is around 6.75cf and on the low low bass it sounds killer smooth,clean and hard hitting but the long test tone higher frequency notes I get a ton of nastyy muddy boominess that is unpleasant and uncontrolled sounding, I plugged the port and it sounded Awsome but I lost about half my output... unacceptable. I also screwed up when building my box I put the port in the center vs off to one side like the plans and took the 12" rear leg and made two 6" opposing legs but forgot to make the width half so each side leg has the same port area as main center port making my tuning 35/36 vs 29. Any input would be appreciated...

I built a 100L sub tuned to 20hz, and used a 9.9cm/ 3.875" diameter port. Then I built a second version using 2 ports that were the same 9.9cm diameter. Comparing the two, the single port design had noticeable low frequency compression @80dB+, and the THD measurement showed a peak of 10%+ from 20-30hz. The 2 port design had no compression at 80dB, and THD was 2% at 80dB. (The sub is built into a full range floor standing speaker, so I have vertical height for tubes the full length of the port.)

I like the sound of an overly long port. In fact, I mounted some tiny speaker cones at the end of some wrapping paper tubes, and it sorta sounded good! (A little echoed though.) the resonance frequency of the smaller one that I had was 58hz. I could not tell the bigger one though.

For a ported box or 4th order bass reflex box 16 cubic inches is great but that number is different for other boxes like a 4th order bandpass box where you would want more like 20 sq inches of cone area.

Actually i didn't understand. Tell me if i want to make an enclosure of 1.5 cubic feet to tune it at 32 Hz. What will be the dimensions for both round ported box and slot ported box?

Very good video. I tend to like 12 to 13 sq" of port space when I'm tuning for deep bass 29 to 32 hz. If I'm tuning a little higher I'll shoot for 14 to 15 sq". But to each their own. It's a matter of what works for you. And just to help those out that don't know you just simply multiply width times the height of your port to get the square inch of it. If you want 12sq " of port space for example you will have a 3 inch wide by 4 inch tall port if you had 1 cubic inch of airspace in your box.

I've gone by the enclosure volume to determine port area but I've heard about using cone displacement as well to calculate it as well. Both can be applied and I think it all boils down to the application and skill level.

Very accurate, great detail and description. Good video bro. Keep it up.

can you make a video on how to design a subwoofer box?

Is there any difference between the resonance frequency of the port itself and the resonance frequency of the system (i.e., the box plus the port)? I have come across some texts that describe them as distinct frequencies. Thanks for your help!

yes there's a math to the correct port size .. I owned a custom car stereo business back in 80s 90s we built hundreds of sub boxes we called it tuning the box ..the port is crucial to the specs of the box and cubic internal air space also is crucial also depending on the speaker used

if i have an 18 "speaker ... how to determine the box volume and port on the speaker box ... according to the data on the speaker ... thanks

A large or small port depends on Thiele-Small parameters of the speaker and what frequency Yuit want the box tuned to. Flared ports are always helpful.

Medium ports have been good to me! “commented before I watched” thanks man I build probably 10 to 12 box’s a year an have always wondered but just used common since to keep it strong an quiet!

hey man, love your info. I have two of bowers & wilkins ccm382, i like to make my own speakers for each side of my TV, how can i calculate how big the speaker box should be?

Heya. Valuable info. The technology came forward a lot, and nowadays if you know what you´re doing, and use high end drivers, you can use the port very differently. No need to optimize the port itself for best accoustical performance anymore. Golden ages. Now I can afford to optimize the port for impedance shape, for cooling, Group Delay and transient response (boomyness) and such. It is great helper to make efficient compact system now, instead of desperate need for speaker to produce any SPL at the bas region. That way I can afford to put a 21" speaker into compact 230l box, measuring 58x58x76cm including feet, handle and 100mm casters, load two into european sized car, and make quite loud gig for 150-200 people. Hope IPAL and M-force technology comes forward some more, so we increase the power density even more.

... definitely one of those critical aspects, often overlooked in DIY's...

Below are some notes I would like to make. I'm aware it is essentially a novel in length, but when you're passionate about a hobby that is just what happens. lol 1.) Xmax is normally a figure of one-way travel, not Peak-to-Peak, also not to be confused with Xmech for those who are curious. 2.) The ports themselves shouldn't generate 'wind' (Air Flow) or essentially displace air from the port volume, it usually occurs below fundamental tuning due to the rise in velocity prior to the reduction after once you've extended well below fundamental tuning. Rather the most idealistic scenario is limiting vent velocity so that the column of air within the port resonates with minimal surface/ cross-sectional area resistance which would cause turbulence. 3.) Port Area's relation to Resonance is correct, though what is largely important is driver selection, this will be covered after the next statement. There is a caveat here, where you move into the B.V.R. [Big Vent Reflex] territory. This is a hybrid between a Bass Reflex, and Quarter Wave Pipe where you're coupling the net volume, chamber length, port volume, and port length for the fundamental tuning which if done correctly will significantly increase damping apposed to an average net volume and less lengthy port than a BVR. Within Horn Response, you can view the Impulse Response, or export the Impulse Response to a .Wav file and make an audible comparison between enclosure adjustments to get a rough idea for Impulse attack, sustain, decay and release. Prior to doing so, it is best to use the Filter Wizard to set the theoretical subsonic filter and low pass filter to get a more accurate representation of the transient response. Back to the statement about driver selection mention prior. The drivers' damping factor is incredibly important for more accurate transient response achieving less of a muddy/ boomy response near tuning, though a note to make is that you have to also account for Lossy Inductance [Lossy Le] which for most mobile audio drivers impact them heavily having a rather high Le:Re ratio. The higher the inductance is in relation to the Impedance of the driver the more resonant the driver will become due to the back EMF generated by the coil. Though, 'most' Home Audio, and Professional Audio drivers feature shorting rings, pole sleeves, bifilar winding types for the coil and/or non-conductive coil formers to limit the amount of inductance present. 4.) Though a suggested 'Golden Rule' for In² per Ft³ isn't a bad start, if the program used to simulate/ design the enclosure is capable of it, keeping tabs on Group Delay, Vent Velocity, and Diaphram Displacement, keeping each as low as possible while maintaining a more linear acoustic power profile is most ideal for most applications outside of SPL. As an addendum on the topic relating back to Lossy Inductance, this will shift most mobile audio drivers largely off of what would be optimal without taking it into consideration. It isn't a perfect method but has been measured via RTA in 1/2 Space Radiation in comparison to the simulated result and from our findings, it closely follows the trace with Lossy Inductance calculated. With the additional driver resonance, the enclosure usually has to sacrifice its smaller footprint to increase the net volume, counteracting the peak above fundamental tuning that is caused by the abundance of driver resonance. This also makes many drivers fall outside of the acceptable EBP region to be 'ideal' for a bass reflex alignment, and for those shooting for a 0.707 Qtc Sealed enclosure, it can actually be impossible in some cases. Just here to clarify a few things and present some ideas that most are not aware of. I'm not trying to step on any toes, just explaining what I've gathered over the years since I have been pushing to learn as much as possible within the acoustic engineering field. At the very least it'll steer those who are less technically inclined in the right direction not to overshoot or undershoot port area either because they aren't aware of the effects, or they've been told by others to do one way or the other and end up with poor results. So for that, thank you.

Good video. Also. If you go for say 3 smaller round ports instead of 2 larger round ports the 1st order port resonance goes up

Im building a 5.25" pc drive bay speaker out of styrene plastic and 2x 3w creative drivers out of a creative travelsound 400, im opting to rear port it and am going to make it rectangular as these seem to work best in my experience, the port will be exactly half the width of the enclosure. these little drivers sound absolutely beautiful with a PAM8403 5V class D amp, the amps are tiny and pack a punch, ideal for drive bays.

Thank you brother for very informative vedio 🙏

So say I'd want 5-8cm wide flared ports on a Celestion TF0818. What length is ideal? If I were to use dual ports, would I be correct in thinking 2 ports of 23mm or 1×30mm? Sounds wrong.

Does the position of the speaker upright, slanted, or flat ,has an effect on the sound, especially the bass?

I think it all depends on your goals ur driver and vehicle, if u r firing into an open cabin jt will vary then if u have it dead against a back gate

Good explanation thank you

Hello , port square inches should be calculated per net internal volume or total internal volume

I got amazing results by mounting a full range 4 ohm 5" dia. speaker in a thick cardboard tube fully sealed. Powered by a 5 watts per channel 8 track tape deck (Muntz brand).

My method is to use 2 or even 4 ports, I think that this is a solution to mix pros of both methodes. It working very good. ;)

Hello i m from india Which is best low and loud frequency enclosure size and port size please suggest me..... I have 2 sub 530 rms Svc parrelel 2ohm to sony Mono Amp 750 rms 2 ohm...... Please suggest me size ...

Thanks for this information brother. I truly know how This sound travel makes a big difference. Brace on the port. Again thank you ✌✌✌✌✊✊✊✊👍👍

what about for a 2x15 Guitar cabinet??? it has 3" holes ...... 2 of them. Seems way to much air escaping, what do you think?

great video ... can you please also explain in your coming videos what will have the influence if a large diameter port need to be very long in order to tune the box low? i mean any adverse effect it would cause? thanks

I have twin 8" ports for my single 18. Sounds great. Plays anything i send it accurately.

good day sir thanks for a knowledgeable video. may I ask what is the best dimension for an 12" L ported box design?

Question this is great for sound quality and I'm not into SPL but I do you like to move hair. Can having certain size ports increase my chances of having a standing frequency in the vehicle for hair tricks? I know this might be a little vague of a question but any input would be welcomed. I would like to do it with ported boxes because I don't have spacing to do anything but I one-to-one fourth order inside of my cab

Actually WinISD shows the air speed at different frequencies so you can change the diameter and check the speed so no more calculations is needed

Degital design chart for the port? Is that for sound qaulity bass or spl bass?

Can i use 4ohm 30w subwoofer instead of 3ohm 10w woofer (stock) in speaker?

I am trying to build my first subwoofer box on my own with the help of my father-in-law who is your carpenter and has the tools to do all the round do you know flares and 45s and everything else you need to get the air flowing properly I’m also looking in on how to build more complex boxes like fourth order six order stuff like that but you kept it simple which is what I need and give me information on where I can find the dimensions I need for my subwoofer thank you very much I subscribed and liked your video because it is awesome keep up the good work.

Thanks man, my 400 pages Book on how to make your loudspeakers wasn't that clear

Thanks for this tutorial

4:22 Mmmmmm~~~~~ Thank you man, I really enjoy the video. highly appreciated.

This really helped. Thanks man!

I made a box container a subwoofer, all-range speakers and a pair of tweeters. I have 2 ports where air goes out/in, but the pressure from the subwoofer seems to push the all-range speakers out also. Not noticing any effect on the sound though, but would it be a massive problem those move along? If so, would just add another port to release pressure be the best option? Or would it sacrifice the bass?

Anyone know if the woofer diameter matters? I have different online calculators saying one 4" port should be from 3.8" to over 100 inches to get 25hz in 8 cubic feet. They cannot all be correct. None ask about the driver itself. Is a 10" sub going to have the same response as an 18?

To eliminate all the above problems use a sealed baffle.

Thanks brother from India

Can you give me some measurements for a box. I need a box for my Escalade. I'm putting 2 15 inch subs and they need 10 cubic feet of air volume. Can you send me some measurements please sir. I'd really appreciate you

If you use WinISD or any other program that can estimate port velocity, try to keep it under 30 m/s (100 ft/s)

Sir just correct me if i am wrong. Example i have a total 2.75cu.ft of the box. Am i right? My port wide is 2.75” and lenght of 26”? Just correct me sir if i am wrong of my coputatuon for my width 2.75” width?

Thats to get you in the ballpark. Actually ideal port area is based on xmax, power and tuning you want to model it out vs taking a blind guess based on general recommendations.

Is the box area example before or after adding the port?

The info you got there from DD about cubic feet and port calculations. Is that before sub and port displacement or after?

Thanks for the info! May i email you with some questions? Thanks

Does this apply to 4th order bandpass boxes for cars?

I have noticed this. I had a Yamaha surround speaker with two tiny ports, less than an inch wide, and 2 inches long. It had a 4 inch woofer. The issue: not tuned well. Muddy sound, port chuffing. The ports are literally cardboard tubes glued to the front particle board panel, so the ports even have a little lip on them that is smaller around than the port itself, which just makes it worse. Same thing with many Onkyo surrounds. Funny thing is, the ports on the speakers from many of the cheap “all in one units” mini stereo systems from the 90s and early 2000s (Sony, Aiwa, Jvc, etc.) are actually tuned extremely well!

You can make 3x 5-7cm small port's, if is a big port not possible to make or the sound are not that what you want. A little bit longer time to work, but the result Convincing. I'm testing it passive radiator with 3x 7.5cm ports and my reaction to the first sound was only a "WoW", it was not possible to make one big port, not enough space/distance from speaker magnet to the back side of the speaker box with the ports, in the middle not possible to make a port, but 3x small port's like triangle around the magnet.

🔴Does 16 sq inches per cubic foot also apply to aero ports, if not is there another number.

Thx from Italy 🙌🏻

Good work

καλησπέρα σας να σας κάνω μία ερώτηση αν το μεγάφωνο των τοποθετούσατε ανάποδα ο μαγνήτης έξω από την κούτα είναι σωστό ή λάθος ....ευχαριστώ πολύ εκ των προτέρων

Doesn't total surface area of the diaphragm combined with x max have anything to do with port area? One website I went to said I should go with a short two and a half inch port, well another website suggests that I use a very long 6-in port. But both suggest that these ports will result in 34 Hertz tuning. How can that be? Doesn't Port area also affect tuning along with diameter and length? I have everything I need to put this sub together. But I am absolutely befuzzled by Port area. Trying to do a 1.25 Cube box tuned at 34 HZ for a single low budget 10-in sub, to be installed in a single cab pickup truck. Port area dramatically affects the external dimensions of the box. And my space is tight.

The primary issue with using a ratio of vent area to box volume is that it ignores the volume displacement of the cone. It doesn't take a lot of thought to see that a 6.5" woofer and a 10" woofer in the same 1cuft box might require different diameter vents. Even if driver diameter is kept constant, Xmax varies wildly from driver to driver, also affecting the total volume displaced by the cone. A better calculation would be Sv = 0.02032* Fb * Vd where Sv is the vent area in square inches, Fb is the vent tuning frequency (yes it actually makes a difference what the tuning frequency is) and Vd is the volume displaced by the cone in cubic inches (Sd x Xmax). 0.02032 is a constant that will result in a vent area to keep air speed in the vent to ~ 5% mach, or about 57feet/second. This is good for a quiet environment like in a house. In a car, and especially one where the enclosure is in a trunk, higher speeds (more chuff) can be tolerated but should not exceed about 9%mach (100fps).

What's the calculator link address (at 41secs) please?? I had this, but lost due to computer failure. Thanks.

if you're increasing the area of the port.. doesn't this also affect the length as well... if so what ratio?

I’m not the best with math, but I have 2 18” subs in a 40”x42”x33” box. And 4 4” circle ports 4” deep. Feels about 65hz but idk. How would I make it lower?

It all depends on your specific speaker measurements... It is not like you can make it big or small at your will

Is this the same for normal speakers (not subwoofers)? I am building a custom bluetooth speaker and am trying to calculate the correct port length. My driver is 4" diameter, with a enclosure volume of 0.21 ft cubed and a resonant frequency of 81.4 hz

How do you calculate your port length... im goning for spl and have read not to be any longer than 8- 10 inches ... problem is with my port area being right at 8-10 inches in winisd im getting my tuning higher than I would like?? Wanting a spl box with good bandwidth in a accord wagon

I don't know if I'm wrong but when you used the vent diameter calculator you entered 60mm for Xmax which is insane because that means there is 60mm of excursion in either direction giving total of 120mm and mechanical limit would be absolutely insane. Xmax of 30mm would be much more logical.

My subs only have (15" planet audio)13mm and (10" power acoustik) 15mm of excursion. That huge port may have been recommended because of your giant excursion # ? Though I'm mindful of subs specs I lean towards the larger port size, My rough general rule For 10s and 12s I use 4" and for 15s I use 6" ports or close combo equivalent. When building slot ported boxes I keep the general size rule in design but can be bigger or smaller depending on the so many factors . Also I prefer my built auto sub enclosures tuned around 31hz to 34hz , so my ports are a big factor . I'm currently pondering a single 15" with 2×6" ports that will be like 30+ inches long each that will be mostly external and a part of the exterior design for minimal box size(still 3+cu.ft.net.) and a unique look without skimping (I'm bored with plain old gray/black undersized generic prefabs). Let the subs breath DEEP! I'm "BRAINS over brand " in Tacoma Wa .

Simply..... Which one produce good bass effect????

Thanks for the good video, but isn't a flat long rectangular port the best option, for it allows enough cross section surface while offering good damping, thanks to a high side wall surface to cross section ratio? First time I heard a speaker with a so called "lamellar flow" wide thin and deep port, it struck me how deep the bass frequencies were reaching, without any boominess or ringing.

Good job thank you

I have a 4 inch subwoofer of home theatre. I want to design a enclosure for it. (0.35 ft3 is the enclosure volume) . Can I use a 1 inch diameter pipe with it?

Which port is best for deep bass Subwoofer

Love your vids but it way too technical for me. 😅 Can you recommend a box size and type for my Audiobahn Alum12Q. I have a 30L sealed box. Wonder if I can do better.

Have you ever done a video on port length, port shape and port placement/location?

How would I find my ports displacement?

Is varation of subwoofer how ohm is and watts but im with big port because have more bass port is Air when sub breathe in Explorer bass exurcion

Learn alot from this vid thanks

Im old fashion, i never built a slot port. I have always use PVC pipes for my ports. The longer the port, the lower the sub will play. For 12" subs I use 3"-4" Diameter ports, for 15" subs I use 4" diameter ports and for 18" subs I use 6" diameter ports..... my ports never whistle or build up turbulence I like the video btw

What's important (and the original purpose) of a port was that it STARTS (at the back of the driver) the size of the driver, then increases in size (preferably radius) by at least 2x - by the time the channel exits (port opening). Should look like an ice cream cone : ) Listen to your small phone speakers THEN put a funnel right on the speaker and watch it get 3 times louder 👍

If the idea of a subwoofer is low bass..I would have to admit the lowest bass that I ever heard was without a doubt a sealed enclosure. I will never use a sloppy port system again but, then again I enjoy controllable, accurate bass.

Alot of this also depends on the environment, loading, and cancelation.

i made a box completely ignoring the consequences of turbulence. tuned to 24hz with a small diameter 2ft long port that made a massive amount of turbulent noise. luckily for me it was in a sealed trunk and i never heard the noise allowing me to achieve stronger dampening at a low tuned frequency. i meant to tune lower but whatever i did ended up producing stronger resonance at 24hz which i was happy with nayway.

can you please give us a simple chart like 8 inch speaker then the box should be length in to breath the port should be dia and length. if the speaker is 12 inches the box should be length into breath with a port hole in size. it could be approximate to get the best with what we have. regard from India

Video topic suggestions: restive port and passive radiator :)