AVS Forum banner

1 - 20 of 253 Posts

·
Registered
Joined
·
133 Posts
Discussion Starter #1
Hi friends! I'm new to here... 😊

I just designed something that I believe would find me the finest lows. I made my own theory on how it measures in propotion to the speaker. I sketched it below just for reference. However, much interesting will be my silly theory.

I make two rooms of same volume by centering my speaker, what theoretical here is, that volume divided by three (to find how long/wide/tall) is equal to the diameter of the speaker plus two inches, for example, if I choose a 10 inches speaker the rooms will be 1728 cubic inches each. Now my slot port comes, its width is equal to quarter the size of the room volume divided by three, back to that example, 1728"/3 = 12" and 12"/4 = 3" or the port width.

To better understand what I explained here, refer to the sketch below as you read these calculations.

I'm pleased to know if I'm silly enough to absolutely ruin my project, because this funny thought is mine and of course I'm not a subwoofer maker.

But, my friend who is a subwoofer maker is very excited about my design, so I'm eager to get your opinions...

Thanks in advance...

Sub~2.png
 

·
Registered
Joined
·
2,233 Posts
This looks like a 6th order parallel bandpass design except that the ports from the two chambers exit at the same point (that may restrict airflow and lead to compression). You can easily model this type of enclosure in a few different modeling programs.
 

·
Registered
Joined
·
133 Posts
Discussion Starter #3
This looks like a 6th order parallel bandpass design except that the ports from the two chambers exit at the same point (that may restrict airflow and lead to compression). You can easily model this type of enclosure in a few different modeling programs.
Thanks for replying me dear...

As you said, I recently learnt this is close to 6th order bandpass. How about my theoretical idea by the way?
 

·
Registered
Joined
·
609 Posts
Are you trying to do a infinite baffle 6th order band pass room? I could be wrong but i don't think there is anything to be gained there unless you are thinking about running 8 x 24's on the baffle wall. I know @MKtheater did a ported one.
 

·
Registered
Joined
·
133 Posts
Discussion Starter #6
Are you trying to do a infinite baffle 6th order band pass room? I could be wrong but i don't think there is anything to be gained there unless you are thinking about running 8 x 24's on the baffle wall. I know @MKtheater did a ported one.
No dear, it's a subwoofer enclosure design I intend to build from MDF (if you meant a physical room).
 

·
Registered
Joined
·
11,787 Posts
Don't use dear in every post, or any post. That is short for dearest, i.e. the ones closest to the heart. Wife/lover etc

Hi / Hello / Friend / Bro / Man / Dude is acceptable, however it's best to just start the sentence directly with the question or answer after the introductory first-post.
Open internet forum is informal, no need for the letter head/tail formalities.
Moving on...

I make two rooms of same volume by centering my speaker, what theoretical here is, that volume divided by three (to find how long/wide/tall) is equal to the diameter of the speaker plus two inches, for example, if I choose a 10 inches speaker the rooms will be 1728 cubic inches each. Now my slot port comes, its width is equal to quarter the size of the room volume divided by three, back to that example, 1728"/3 = 12" and 12"/4 = 3" or the port width.
I don't understand.
In any case, the port and chamber dimensions should be proportional to the desired tuning frequency, high/low bandpass points / rolloff characteristics that you intend to have, this is based on t/s parameters, not magical ratios of cone diameters.

Not to stifle the imagination but...
If you can imagine it, then there is a good chance that some speaker/subwoofer guy out there has already tried it, likely with no success, otherwise it would be patented and they'd be rich(in-theory).
The old Bill Gates approach of: you are only as rich as you are aggressive and secretive with your filed\approved patents, sue & monopolize until the wealth comes... hehe! :p

Rather instead, it definitely has to be based on valid\already-proven science or you won't achieve the desired performance/characteristics, or you'll even damage the subwoofer at high power, or just cause undesired distortions (port noise etc); or all the above...

The maximum efficiency is 100% usage of the front and back of the cone.
Which is impossible because it has to be delayed, which results in either a phase shift or a shift in frequency, or both.
The only exception is: a single-notch subwoofer-box designed to be burped once, at 194db, at 1 frequency, with a million watts behind it, a cement coffin on wheels...
 

·
Registered
Joined
·
133 Posts
Discussion Starter #8
Don't use dear in every post, or any post. That is short for dearest, i.e. the ones closest to the heart. Wife/lover etc

Hi / Hello / Friend / Bro / Man / Dude is acceptable, however it's best to just start the sentence directly with the question or answer after the introductory first-post.
Open internet forum is informal, no need for the letter head/tail formalities.
Moving on...
Thanks for your advice... I was just being a bit polite in hope of getting a nice answer cos I'm not a subwoofer maker in the 1st place, then I'm a foreigner. In our country we use many forums so I have enough experience but nothing about DIY things cos we're used to buy them in a store. 😉

I don't understand.
In any case, the port and chamber dimensions should be proportional to the desired tuning frequency, high/low bandpass points / rolloff characteristics that you intend to have, this is based on t/s parameters, not magical ratios of cone diameters.

Not to stifle the imagination but...
If you can imagine it, then there is a good chance that some speaker/subwoofer guy out there has already tried it, likely with no success, otherwise it would be patented and they'd be rich(in-theory).
The old Bill Gates approach of: you are only as rich as you are aggressive and secretive with your filed\approved patents, sue & monopolize until the wealth comes... hehe! :p
I really imagined for a while that I'd rule the world by exposing this and be another patented BOSE man. 😂

Rather instead, it definitely has to be based on valid\already-proven science or you won't achieve the desired performance/characteristics, or you'll even damage the subwoofer at high power, or just cause undesired distortions (port noise etc); or all the above...

The maximum efficiency is 100% usage of the front and back of the cone.
Which is impossible because it has to be delayed, which results in either a phase shift or a shift in frequency, or both.
The only exception is: a single-notch subwoofer-box designed to be burped once, at 194db, at 1 frequency, with a million watts behind it, a cement coffin on wheels...
Okay, forget everything I said about my theory, my title has almost implied it. I'm just wondering how my design would be with a proper modelling, any comments...?
 

·
Premium Member
Joined
·
5,163 Posts
FTR sorta reminds of the guy, iirc, 5-7+ years ago,
was trying to sell us on the concept of a sealed sub inside a ported cab-
his plans of course . . . nominal $
never posted any real performance
and didn't get much traction
 

·
Registered
Joined
·
1,601 Posts
There are some horns that are kind of designed this way with an "intake" and a "exhaust", but they are divided at the end/entrance
 

·
Registered
Joined
·
1,723 Posts
Thanks for your advice... I was just being a bit polite in hope of getting a nice answer cos I'm not a subwoofer maker in the 1st place, then I'm a foreigner. In our country we use many forums so I have enough experience but nothing about DIY things cos we're used to buy them in a store.



I really imagined for a while that I'd rule the world by exposing this and be another patented BOSE man.



Okay, forget everything I said about my theory, my title has almost implied it. I'm just wondering how my design would be with a proper modelling, any comments...?
Different order bandpass concepts are used for various reasons, one of the more popular used here is to move more of the useful energy into the frequency response we want to use (20-80hz).

A 6th order parallel like you pictured has the advantage of a standard ported box and a smoothing of the higher frequency range (40-80hz).

You shared the exit entry for both ports and this doesn’t have any benefit other than possibly saving a little space. MTG said this could lead to compression and that’s bad, it means you are losing out on SPL (sound energy) because the ports are fighting each other for resources.

6th orders are good boxes though, a bit complicated to build but only slightly more difficult to model over a ported box. Not many drivers do well in these types of alignments however.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
133 Posts
Discussion Starter #13
FTR sorta reminds of the guy, iirc, 5-7+ years ago,
was trying to sell us on the concept of a sealed sub inside a ported cab-
his plans of course . . . nominal $
never posted any real performance
and didn't get much traction
I'm not much aware of this subject though a bass lover. I was just sharing my thought with you, that's why I called it "silly". However, I felt my design has something cos it basically shows the characteristics of a SBP.
 

·
Registered
Joined
·
133 Posts
Discussion Starter #15
There are some horns that are kind of designed this way with an "intake" and a "exhaust", but they are divided at the end/entrance
I wasn't expecting that. I've never seen a folded horn nature through my design. I gotta know this is much closer to 6th order bandpass later.
 

·
Registered
Joined
·
133 Posts
Discussion Starter #16
Different order bandpass concepts are used for various reasons, one of the more popular used here is to move more of the useful energy into the frequency response we want to use (20-80hz).

A 6th order parallel like you pictured has the advantage of a standard ported box and a smoothing of the higher frequency range (40-80hz).

You shared the exit entry for both ports and this doesn’t have any benefit other than possibly saving a little space. MTG said this could lead to compression and that’s bad, it means you are losing out on SPL (sound energy) because the ports are fighting each other for resources.

6th orders are good boxes though, a bit complicated to build but only slightly more difficult to model over a ported box. Not many drivers do well in these types of alignments however.


Sent from my iPhone using Tapatalk
That's exactly what I wanna know excepting my silly theory now. How will it result as two airflows meeting each other at the exit...?
 

·
Registered
Joined
·
1,601 Posts
I wasn't expecting that. I've never seen a folded horn nature through my design. I gotta know this is much closer to 6th order bandpass later.
Well some Horns put the driver in a sealed cabinet. Some work similar to your design with 2 paths to the driver. The GSG devastator is one.
 

·
Premium Member
Joined
·
24,484 Posts
There are some horns that are kind of designed this way with an "intake" and a "exhaust", but they are divided at the end/entrance
A tapped horn came to mind when I saw it.

In any case, speculation about how well it would work could be ended by modeling.
 

·
Registered
Joined
·
133 Posts
Discussion Starter #19
Well some Horns put the driver in a sealed cabinet. Some work similar to your design with 2 paths to the driver. The GSG devastator is one.
I took a look at the GSG one, that's a very complex design and seems to be a well engineered one. But, as you said, unlike the horn designs I've seen before, its speaker is mounted in a vented room.
 

·
Registered
Joined
·
133 Posts
Discussion Starter #20
A tapped horn came to mind when I saw it.

In any case, speculation about how well it would work could be ended by modeling.
Really...? I've never seen any SPB kinda tapped horns, but I'm not much into the subject after all.

Okay, can you suggest me a good modelling program? And as far as you know, how will it be when my two ports meet at the exit point? Do you really think it'd cause any harm to the overall SPL?
 
1 - 20 of 253 Posts
Top