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Sealed versus ported boxes in a 2-way speaker?


pmcuk
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3 minutes ago, jobseeker said:

I wonder just what the ratio of ported to non-ported speakers currently available is, in the general market. I’m guessing a lot more people out there are likely to have ported than non-ported. Though I have absolutely no evidence for that 😀  I can’t recall ever owning a sealed-box speaker, over many years. I wonder how that happened. I have used several large speakers in a small room to great success - probably more so than with small ones.

Here's a thread about sealed cabinet speakers:

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This topic need a few graphs. :D

Here we can see that alhough the port manages to keep the response flat down to a lower frequency the sealed cabinet produces more extension (the port peaks at the tuning frequency but the response falls abruptly below that):

209PSBfig5.jpg

PSB Imagine B, anechoic response on tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response, with complex sum of nearfield woofer and port responses plotted below 300Hz (blue), and with woofer response with port closed (red).

https://www.stereophile.com/content/psb-imagine-b-loudspeaker-measurements

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I think the main reason for ported speakers is to get a lower bass extension from a smaller box than with a sealed one. These are more domestically acceptable and so have become popular.  However to get this it has to use two resonant systems ie driver/box and port/ box. There's a lot of ways these two can work together, for example different port tuning and you can get it right or wrong in my opinion. There's been a lot of work done on this subject over the years to help designers avoid some of the pitfalls so as usual its more about how a particular technique is used rather than the technique itself.

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Here we see that the sealed cabinet goes quiet when the signal stops (Yamaha NS10), but the ported's output/resonance lingers on and decays at a much slower rate (Tannoy A600):

4LDpcZS.png

iDQsmTm.png

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Super Wammer
2 hours ago, lindsayt said:

For a cunnning plan, go for 12" or larger woofers and then you can go 1, 2, 3, 4 or 5 ways with a chance of good sonic results for the money...🦊

My cunning plan has my home built/developed 18" bass drivers in 140 litre cabs .... ported (100mm dia port) with 'monitor' style 3 way seal cabinet speakers running 8 " mid bass, 2" soft dome midrange and 1" tweeters 😀

Ive even added batpur supertweeters so now a full 5 way setup  - sonic results are fantastic imho for probably 1/10 of the retail cost of such speakers 😁😁😁😁

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Step response of closed vs. ported (closed stops almost immediately):

c8jPcND.png

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Super Wammer

  🕳️   🐧

Edited by garn63
Pp ppp
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But a ported design has advantages too such as increased bass extension, higher SPL capabilities and higher sensitivity.

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15 minutes ago, garn63 said:

Here we see the effect of some (sealed box) small spkrs.  =   :)

Here we see the effect of some (ported) small spkrs.    =    :)

It's very much as I thought actually, but for fun we thought we would test the general consensus to graph readings of small spkrs.........

Here we see the effect of graphic readings for (some) small spkrs.   =   🙄

I genuinely hope this helps. Am not going to claim anything unequivocal but will leave enthusiasts to hopefully (without bias) come to their own conclusions.

zSorrh2.gif

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Super Wammer

🕳️

Edited by garn63
n.w.i.
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I don't think any of the KEF or Leak speakers I own have got ports in them. I have a pair of DM4s which I think are ported at the front, and my Tannoy Turnberries also have ports. Ports seem to be a modern invention, designed to make you think you're getting more bass than you really are. But hey, so long as you like the sound you've got, does it really matter?

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6 minutes ago, audio_PHIL_e said:

Ports seem to be a modern invention

Er, no. They've been around longer than I have been interested in hifi, so more than 40 years. So not modern at all.

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End of discussion 

1140164878_images(29).jpeg.5dc53c86d240d584b9ab0cde8b023b44.jpeg

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21 minutes ago, Tony_J said:

Er, no. They've been around longer than I have been interested in hifi, so more than 40 years. So not modern at all.

That's modern in my terms of reference

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6 minutes ago, audio_PHIL_e said:

That's modern in my terms of reference

:doh:

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