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Discussion Starter · #1 ·
I've always heard this is not a good idea..


I have two sealed 18's and am going to convert to ported boxes. If using a MiniDSP would it be a big no-no to mix ported and sealed? Was thinking about picking up 2 more Dayton 18's for a total of 4 subs. two would be ported, two would be sealed. I'm thinking I can EQ them individually with the MiniDSP having the two sealed on one EP4000 and the two ported on another EP4000. Thoughts?
 

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Model both versions, see the difference in phase response. More pertinent, look at the difference in frequency response, excursion and maximum SPL and you'll see why there's nothing to be gained in mixing them.
 

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Quote:
Originally Posted by Gomdaf  /t/1524862/blending-ported-and-sealed#post_24544753


I've always heard this is not a good idea..


I have two sealed 18's and am going to convert to ported boxes. If using a MiniDSP would it be a big no-no to mix ported and sealed? Was thinking about picking up 2 more Dayton 18's for a total of 4 subs. two would be ported, two would be sealed. I'm thinking I can EQ them individually with the MiniDSP having the two sealed on one EP4000 and the two ported on another EP4000. Thoughts?

Sealed will have far less group delay while ported will have noticeably higher GD. Subjectively speaking; you will have no accuracy in bass response. While you can reduce box size on ported ones to have GD close to sealed ones; but then you won't enjoy the high output trait of ported subs. So, I don't see the need to mix both. Hoffman's Iron law is in full swing
 

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Quote:
Originally Posted by braveheart123  /t/1524862/blending-ported-and-sealed/0_100#post_24545612


Sealed will have far less group delay while ported will have noticeably higher GD. Subjectively speaking; you will have no accuracy in bass response. While you can reduce box size on ported ones to have GD close to sealed ones; but then you won't enjoy the high output trait of ported subs. So, I don't see the need to mix both. Hoffman's Iron law is in full swing

ported vs sealed group delay:



IMO, just go ported and enjoy the extra output.
 

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Discussion Starter · #5 ·
Ok, thanks. Guess its a bad idea to mix. What about ported mains like DIY Tempests with sealed subs? I'm guessing that doesn't matter correct?
 

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I have read, (no practical experience here on my part), that getting ported mains to blend with any subs might be difficult. I am unsure if sealed versus ported on the subwoofers end will make a difference, but, I would assume that sealed subs would be easier to blend versus ported ..
 

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Quote:
Originally Posted by Martycool007  /t/1524862/blending-ported-and-sealed#post_24545868


I have read, (no practical experience here on my part), that getting ported mains to blend with any subs might be difficult. I am unsure if sealed versus ported on the subwoofers end will make a difference, but, I would assume that sealed subs would be easier to blend versus ported ..

I asked Wayne about this when I was building the 4 Pi's

His response was:


"I do not think it is valid to consider sealed mains to be easier to integrate with multisubs. In fact, I'd say this presumption goes against the whole multisub concept, which is to blend sound sources having various phase relationships and physical locations in the modal region.

The additional extension from vented mains helps increase overlap between mains and flanking subs. The venting also reduces excursion. It is a good thing, all the way around."


This is regarding his multisub approach, but wouldn't the same apply to a subwoofer? (granted it isn't crossed nearly as high)
 

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Quote:
Originally Posted by Martycool007  /t/1524862/blending-ported-and-sealed#post_24545868


I have read, (no practical experience here on my part), that getting ported mains to blend with any subs might be difficult. I am unsure if sealed versus ported on the subwoofers end will make a difference, but, I would assume that sealed subs would be easier to blend versus ported ..
If this was an issue wouldn't all those happy tempest main owners have chimed in. I have ported mains with ported subs and they blend well.
 

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Quote:
Originally Posted by Bill Fitzmaurice  /t/1524862/blending-ported-and-sealed#post_24545077


Model both versions, see the difference in phase response. More pertinent, look at the difference in frequency response, excursion and maximum SPL and you'll see why there's nothing to be gained in mixing them.


What if you tweak the distance settings for all of the subs and put a HPF right at tuning for the ported subs? We tried this at Archaea's place and they measured well and subjectively it was an improvement over running just the ported subs or just the sealed subs.


I ask because I'm thinking about adding ported subs to my sealed sub setup.
 

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I realize that the following graphs don't represent all the possible pitfalls of matching alignments, but here are my results:

 

Original sub(ignore SPL, it was not calibrated):

 

Ported PSW110(am I banned forever now?)



 

Upgraded to sealed dual opposed:

 



 

Added the Polk:

 



 

And finally, with EQ applied via miniDSP(no EQ below 20 hZ, i closed my two sets of french doors in my 2525 ft3 room.)

 



 

I know these are not DIY subs, but I felt this was relevant to the topic, and I've been lurking on DIY lately(the Polk needs to go)
 

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Quote:
Originally Posted by braveheart123  /t/1524862/blending-ported-and-sealed#post_24545612


Sealed will have far less group delay while ported will have noticeably higher GD.
Noticeable on a graph, but not in practice. For GD to be audible the numbers would have to be literally off the chart.
 

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Quote:
Originally Posted by Bill Fitzmaurice  /t/1524862/blending-ported-and-sealed#post_24546549


Noticeable on a graph, but not in practice. For GD to be audible the numbers would have to be literally off the chart.

I have a set of ears and can discern even the likes of Rythmik FV15HP in 2 ports open, low damping, rumble filter on, 20Hz hz to be not so accurate below 30Hz. All of that is attributed to high GD i.e. close to 72m/s at 20Hz. And I've heard many subs just like so many people on this forum.

But then at the same time, it's always a trade off between accuracy, output, extension, size.
 

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It seems like integrating like subs is hard enough without mixing alignments. If a guy has them on hand sure try and see what you can come up with (the more gear you have on hand will/can be a help) but imo I would never buy or build a different alignment with the plan of mixing.
 

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"I have a set of ears and can discern even the likes of Rythmik FV15HP in 2 ports open, low damping, rumble filter on, 20Hz hz to be not so accurate below 30Hz. All of that is attributed to high GD i.e. close to 72m/s at 20Hz."


are you sure gd is what you are hearing?
 

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Quote:
Originally Posted by LTD02  /t/1524862/blending-ported-and-sealed#post_24547133


"I have a set of ears and can discern even the likes of Rythmik FV15HP in 2 ports open, low damping, rumble filter on, 20Hz hz to be not so accurate below 30Hz. All of that is attributed to high GD i.e. close to 72m/s at 20Hz."


are you sure gd is what you are hearing?
+1. Earl Geddes would have a field day with that statement, bringing up all sorts of actual technical aspects, starting with the period of a 20Hz wave.
 

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The reason it works for ported mains is we XO well above tuning, otherwise it would be a problem IMO. Above tuning the power output of the port and driver are in phase, no problem. Below, they are down about 24db hopefully.


I disagree that it HELPS to have the port contribute to the multi sub ideology. The multi subs are still in phase, just at various locations in the room and exciting different modes. Yes, that's a different phase, but still seems different to me. I've often wondered about nearfield subs cause of this. Wether owners delay the nearfield ones or what.
 

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Quote:
Originally Posted by LTD02  /t/1524862/blending-ported-and-sealed#post_24547133


"I have a set of ears and can discern even the likes of Rythmik FV15HP in 2 ports open, low damping, rumble filter on, 20Hz hz to be not so accurate below 30Hz. All of that is attributed to high GD i.e. close to 72m/s at 20Hz."


are you sure gd is what you are hearing?

The Damping switch set to Low on FV15HP in 2 ports open mode while gives the max output as it has the steepest slope, but it also jacks up GD. That gives away accuracy. I would like to set it to Medium or HIgh, but it gives up output in favor of accuracy. Um sure it is the GD that impacts accuracy below 30Hz keeping all things equal.
 
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