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Advanced port tuning

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Thomas Hosker View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Thomas Hosker Quote  Post ReplyReply Direct Link To This Post Topic: Advanced port tuning
    Posted: 20 August 2016 at 11:21am
Im wondering what would happen under a few different circumstances.

First one being a ported subwoofer enclosure with say 4 tube ports of 2 different sizes. Would the port tuning just average out across the 2 different port lengths?

Also another scenario,

If you have a "double tuned" rear chamber with the rear of the driver firing into a rear chamber ported into another chamber thats then ported to the outside. Is there any pros or cons to this? Im assuming it cant be simmed in hornresp but akabak?

Im thinking the second scenario is what void use in the ported horn subs?


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Post Options Post Options   Thanks (0) Thanks(0)   Quote cookie-dj Quote  Post ReplyReply Direct Link To This Post Posted: 20 August 2016 at 7:27pm
A previous thread here Thumbs Up
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Thomas Hosker View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Thomas Hosker Quote  Post ReplyReply Direct Link To This Post Posted: 21 August 2016 at 4:44pm
Cheers dude, only really seems to mention the first scenario i posted. How about the effect of porting a rear chamber into another chamber and then to outside?


Although i noticed a video popped up on youtube the other day and was quickly removed detailing the insides of the Void Stasys X v2. That seems to be a straight up ported bandpass horn arrangement. Although i know the trinity x and other variants were like scenario 1. Hmmm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cookie-dj Quote  Post ReplyReply Direct Link To This Post Posted: 21 August 2016 at 6:11pm
I remember there being a thread on here about someone that designed a bass horn with 2x different horn paths to achieve a wider frequency response.
I think the conclusion was that it wouldn't work well due to cancellations at the mouth.
Not too sure about 2x different ports though
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Post Options Post Options   Thanks (0) Thanks(0)   Quote White Noise Quote  Post ReplyReply Direct Link To This Post Posted: 22 August 2016 at 6:49am


Although i noticed a video popped up on youtube the other day and was quickly removed detailing the insides of the Void Stasys X v2. That seems to be a straight up ported bandpass horn arrangement. Although i know the trinity x and other variants were like scenario 1. Hmmm
[/QUOTE]


That video is still there dude, interesting, it does look like a bp6 with some kind of horn, i thought there would be more to it.... there must be, oherwise the port would be waay quieter than the horn ? unless it has a really narrow tuning band ? 

as for the scenario 2, if you havent already, have a look up on the bose acoustimass, some of those use a similar series tuned arrangement. 


Edited by White Noise - 22 August 2016 at 6:51am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 22 August 2016 at 6:52am
Originally posted by Thomas Hosker Thomas Hosker wrote:


Also another scenario,

If you have a "double tuned" rear chamber with the rear of the driver firing into a rear chamber ported into another chamber thats then ported to the outside. Is there any pros or cons to this? Im assuming it cant be simmed in hornresp but akabak?

Im thinking the second scenario is what void use in the ported horn subs?


That would be the old Bose Acoustimass 5. The downfall of such a design is the limited frequency response. The frequency response is limited due to all the sound projecting through the ports.

 

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White Noise View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote White Noise Quote  Post ReplyReply Direct Link To This Post Posted: 22 August 2016 at 7:10am
Yes thats the one !

depending on how the tuning is used, the limited response could also be seen as a plus side too if you think about it, because its dictates a high and low roll off for the chamber... plus the multiple harmonics of the tunings must mean more gain within the bandwidth ?  that's if i understand it correctly lol

Edited by White Noise - 22 August 2016 at 7:21am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 22 August 2016 at 1:40pm
Originally posted by White Noise White Noise wrote:



Although i noticed a video popped up on youtube the other day and was quickly removed detailing the insides of the Void Stasys X v2. That seems to be a straight up ported bandpass horn arrangement. Although i know the trinity x and other variants were like scenario 1. Hmmm




That video is still there dude, interesting, it does look like a bp6 with some kind of horn, i thought there would be more to it.... there must be, oherwise the port would be waay quieter than the horn ? unless it has a really narrow tuning band ? 

as for the scenario 2, if you havent already, have a look up on the bose acoustimass, some of those use a similar series tuned arrangement. 

[/QUOTE]

Defo not a BP6 - There's a lot you're missing in that video frankly, it's actually just two FLH sections with a bandpass tuned rear section that then ports. There are technically 5 chambers as per marketing, you just need to look for where the divides are.

If anything the old Trinity was simpler.
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Elliot Thompson View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 23 August 2016 at 2:32pm
Originally posted by White Noise White Noise wrote:

Yes thats the one !

depending on how the tuning is used, the limited response could also be seen as a plus side too if you think about it, because its dictates a high and low roll off for the chamber... plus the multiple harmonics of the tunings must mean more gain within the bandwidth ?  that's if i understand it correctly lol


Such a design can compliment a loudspeaker system that can deliver bass on its own. However, if such a design is used solely as the primary source of bass, you will have an abundance of missing frequencies. The ports are not large enough achieve the upper bass region bass at a great amount of SPL. Having a large surface area plays a factor which, the ports cannot accommodate while, offering an extended bass response at the same time.

 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kino Quote  Post ReplyReply Direct Link To This Post Posted: 16 November 2016 at 6:20pm
Hi, The video seems confusing is it possible you could clear a few things up for me? so the rear of both the drivers are in one chamber what is the letterbox port looking bit to the left of each driver and when the videos goes down the horn path is the horn split in two or is it just bracing in front of the driver.

I remember reading an article where rog explains the stays x design where he states there is and intermediate chamber before porting to the outside but from this video it seems to be that the rears of the drivers are ported directly to the five ports on the front of the cab as the guy videoing it seems to have his arm down the port?

i was under the impression it was a 6th order series band-pass design where i assumed a FLH infront of the driver and the rear chamber was ported into another empty chamber which was then ported to the outside.

Im doing loudspeaker design for my final year project and was looking at doing a ported horn design hence my interest but understand if your reluctant to divulge any more information

Thanks
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corell View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote corell Quote  Post ReplyReply Direct Link To This Post Posted: 16 November 2016 at 8:46pm
It is technically an 8th order design. I wont go into detail but imagine a ported horn with another port going from the rearchamber into the hornpath.

You can simulate a serial tuned BR with hornresp. Use vtc as the 1st chamber, apt1 as the inner port, S1-S4 to form the second chamber and S4-S5 for the second port. Interesting results with low qts chassis!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mstep77 Quote  Post ReplyReply Direct Link To This Post Posted: 08 December 2016 at 5:00pm
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