sealed/ported convertible subwoofer

muad

Member
2010-08-26 2:19 am
So I'm trying to work through various builds, with a specific size requirements (need 12" wide, and tall enough to use as stands). This is my first sub build.

I prefer a tight bass. I plan on using it for mostly music and tv, with the odd movie thrown in. I don't need earth shattering 20hz thx level bass.

Right now I'm modeling the Dayton RSS265HF-4. I want to go sealed but I worry that it wont be sufficient in my moderately sized living room. I want to build the sub so that I can stuff a sock in the inside or outside opening of the port to go sealed, but have to option to run ported as well. This will be my only chance at building a box, as I will no longer have access to a shop in a few months.

Gonna use a minidsp 2x4hd and Crown XLS 1502.

PORTED
2 cu ft gross enclosure
3" x 20" port, tuned to 22hz
1.6cu ft net (port/driver volume)
Cone excursion and port velocity will require a filter -4db filter @20hz
After filter - Expected f3 28hz f6 23hz

SEALED
Sock on the outside: 1.85cu ft
QTC: 0.656 - 38.68 Fsc
F3 42hz
F6 31hz

Sock in the inside: 1.6cu ft
QTC: 0.680 - 46hz Fsc
F3 42hz
F6 31hz

1. Is a stupid idea?

2. I can't decide between the Dayton RSS265HF-4 or CSS SDX10
, they model very similarly. The dayton has a little more sealed SPL, but the CSS has more excursion head room. The CSS also has 4m/s higher port velocity with a 3" x 15" port tuned to 26hz. The spl between the 2 drivers track identically in WINISD. I don't know which driver to pick :(

Thanks!!!
 
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wasabii

Member
2021-11-30 10:48 pm
Yes on the Crown and miniDSP combo. I stay away from the so called dual purpose subs for two reasons. Once you plug the sub ports there is no way to decrease cabinet volume for optimum sealed performance. And sub drivers can't be built to do both well. Its either or if your want better than just OK bass.

I just bought a crown amp and Dayton sub to use for primarily sealed use. Built in progress so I can not comment on the Dayton's performance. However the Crown amp works beautifully with the sub I already had in use. I'm stoked about how excellent they sound.
 
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Once you plug the sub ports there is no way to decrease cabinet volume for optimum sealed performance.
i would say Qtc between 0,656 and 0,68 is quite OK for a closed, linkwitz-transformed (via DSP) box.
eventually you could even go bigger.
i suggest you just try it, as you are free to do program the DSP based on your in-room measurements.
once you are happy with one solution you will probably keep it.
you can then also optimize stuffing for the box: complete/much stuffing for closed box, few or none for a bass reflex box.

some more considerations:
a 20" port seems huge!
and a sock will probably not be very air-tight. you should consider some kind of rubber plug, unless you want a aperiodic box.
by the way: the difference between plugging the port on inside or outside is probably so small that it's not worth having both options.
 

muad

Member
2010-08-26 2:19 am
Yes on the Crown and miniDSP combo. I stay away from the so called dual purpose subs for two reasons. Once you plug the sub ports there is no way to decrease cabinet volume for optimum sealed performance. And sub drivers can't be built to do both well. Its either or if your want better than just OK bass.

I just bought a crown amp and Dayton sub to use for primarily sealed use. Built in progress so I can not comment on the Dayton's performance. However the Crown amp works beautifully with the sub I already had in use. I'm stoked about how excellent they sound.
I can't make the sub any bigger than it is. So which do you suggest these two drivers are better for? Make is smaller and sealed? Make it bigger and go ported only? What about these drivers makes it better at sealed or ported?
 

muad

Member
2010-08-26 2:19 am
i would say Qtc between 0,656 and 0,68 is quite OK for a closed, linkwitz-transformed (via DSP) box.
eventually you could even go bigger.
i suggest you just try it, as you are free to do program the DSP based on your in-room measurements.
once you are happy with one solution you will probably keep it.
you can then also optimize stuffing for the box: complete/much stuffing for closed box, few or none for a bass reflex box.

some more considerations:
a 20" port seems huge!
and a sock will probably not be very air-tight. you should consider some kind of rubber plug, unless you want a aperiodic box.
by the way: the difference between plugging the port on inside or outside is probably so small that it's not worth having both options.
Thanks stv!

Unfortunately I can't go bigger with the box. I was aiming for a qtc 0.7. Also, is there any issues with using a 20" port? The sub is going to be 25" tall to be used as stands for bookshelf speakers.

I was playing with winisd, and when I boosted the sealed box the group delay gets much worse. This also happens when I model a high pass filter. Is that accurate? I was trying to avoid boosting the selaed box because of that.
 

wasabii

Member
2021-11-30 10:48 pm
I can't make the sub any bigger than it is. So which do you suggest these two drivers are better for? Make is smaller and sealed? Make it bigger and go ported only? What about these drivers makes it better at sealed or ported?


Thats what I would do. Much R&D has been going in to small sealed boxes 10 and 15 years ago there was way fewer. Mostly it was the guys who focused solely on subs that were making them like Rythmic Miller&Kriesel Rel then Mj acoustics and a couple I'm forgetting. Oh MIRAGE! They made killer bipolar subs, small to large. Last but not least. Mirage was doing them early on (they are an exception they also made really great multi way speakers back then, and BPS. Now there are probably a couple dozen sealed ones out there to choose. Some bomb, others are fantastic if those are your thing, and fit your application also. I love them and stuck with them mostly. I love speedy articulate musical hard punching bass.

Ported will continue reigning supreme with home theatre.
 
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muad

Member
2010-08-26 2:19 am
Thats what I would do. Much R&D has been going in to small sealed boxes 10 and 15 years ago there was way fewer. Mostly it was the guys who focused solely on subs that were making them like Rythmic Miller&Kriesel Rel then Mj acoustics and a couple I'm forgetting. Oh MIRAGE! They made killer bipolar subs, small to large. Last but not least. Mirage was doing them early on (they are an exception they also made really great multi way speakers back then, and BPS. Now there are probably a couple dozen sealed ones out there to choose. Some bomb, others are fantastic if those are your thing, and fit your application also. I love them and stuck with them mostly. I love speedy articulate musical hard punching bass.

Ported will continue reigning supreme with home theatre.
I don't understand. What do you think I should do?
 
I think you should not go sealed and smaller, your suggested volume and qtc seems perfect. Again, that's just my two cents.
You could equalize with linkwitz transform and move group delay down in frequency as much as you want. I really suggest you try it out, ported, closed, equalized and find out what works for you.
 

tim405

Member
2018-11-07 6:54 pm
Is this post related to this one? If so especially (and even if not), I would recommend a sealed subwoofer for music playback even more if you say yourself that you don't need 20hz thx bass which is seldom found in most music people listen to. I personally wouldn't consider a ported subwoofer because;
  • Almost always needs a bigger size cabinet (thus more bracing etc.) which I cannot fit and looks ugly
  • Most of the time higher groupdelay
  • Often port noise occurs in subwoofer application which just sounds cheap and annoying and is hard to avoid (long ports needed which are hard to fit)
  • 24db/octave rolloff instead of 12db with more bass down low which in most rooms which already have roomgain at that frequency makes the bass boomy because the ported sub has already added bass which doesn't happen with a sealed subwoofer which has often less bass but a slower roll off and thus in practise has almost the same bass extension without perceived boom.
  • Everything mentioned here; https://rmsacoustics.nl/papers/whitepaperbassreflex.pdf

I also would advice to buy a different subwoofer as the l26roy has way better performance (especially in the distortion department) for just a bit more money; than the sdx10 (https://audioxpress.com/article/test-bench-the-sdx10-home-audio-woofer-from-css-audio) vs l26roy (https://audioxpress.com/article/test-bench-the-l26roy-10-subwoofer-from-seas). It also has the cone break up higher than the dayton which would be beneficial if you want to cross it over high(er) with a slow slope (first order). I have personally good experience with Seas drivers and enjoyed listening to it in a commercial speaker (grimm ls1be + subs) and I personally don't know anything better or as good (besides scanspeak maybe which I would also recommend) in this size for use between 30-250hz, others may be cheaper or produce a bit more lower bass, but are lacking in performance at mid(bass) frequencies and have often higher distortion.
 

muad

Member
2010-08-26 2:19 am
I think you should not go sealed and smaller, your suggested volume and qtc seems perfect.
Thanks for the feedback!

I'm a little confused. If my suggested volume and qtc seems perfect why do you recommend going smaller? If I go smaller with the ported sealed sub, my qtc will get closer to 0.7, great for sealed but the port needs to be much longer to maintain a low tuning when running ported. If I go smaller, it would be sealed only.


Any thoughts on side mounted subwoofers? This can let me go up to a 12 inch, or even 15" if I really push it.
 
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muad

Member
2010-08-26 2:19 am
Is this post related to this one? If so especially (and even if not), I would recommend a sealed subwoofer for music playback even more if you say yourself that you don't need 20hz thx bass which is seldom found in most music people listen to. I personally wouldn't consider a ported subwoofer because;
  • Almost always needs a bigger size cabinet (thus more bracing etc.) which I cannot fit and looks ugly
  • Most of the time higher groupdelay
  • Often port noise occurs in subwoofer application which just sounds cheap and annoying and is hard to avoid (long ports needed which are hard to fit)
  • 24db/octave rolloff instead of 12db with more bass down low which in most rooms which already have roomgain at that frequency makes the bass boomy because the ported sub has already added bass which doesn't happen with a sealed subwoofer which has often less bass but a slower roll off and thus in practise has almost the same bass extension without perceived boom.
  • Everything mentioned here; https://rmsacoustics.nl/papers/whitepaperbassreflex.pdf

I also would advice to buy a different subwoofer as the l26roy has way better performance (especially in the distortion department) for just a bit more money; than the sdx10 (https://audioxpress.com/article/test-bench-the-sdx10-home-audio-woofer-from-css-audio) vs l26roy (https://audioxpress.com/article/test-bench-the-l26roy-10-subwoofer-from-seas). It also has the cone break up higher than the dayton which would be beneficial if you want to cross it over high(er) with a slow slope (first order). I have personally good experience with Seas drivers and enjoyed listening to it in a commercial speaker (grimm ls1be + subs) and I personally don't know anything better or as good (besides scanspeak maybe which I would also recommend) in this size for use between 30-250hz, others may be cheaper or produce a bit more lower bass, but are lacking in performance at mid(bass) frequencies and have often higher distortion.
Seems like the l26roy is good for ported? will it work sealed? You're right that it performs incredibly well and the price isn't too shabby. The response will need some equalization up higher but I have a minidsp. I'll look into it! Thanks for the recommendation!

Edit: thanks for the link to the paper! I'm definitely leaning hard towards sealed. But I still need to find something that works well into 1.5 to 1.75cu ft net.
 
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tim405

Member
2018-11-07 6:54 pm
Seems like the l26roy is good for ported? will it work sealed?
It is perfectly fine for both applications, in my opnion it models just as good if not better than other comparable sealed aswell as ported subwoofers I've seen.
The response will need some equalization up higher but I have a minidsp
It is just as good (or bad if you think it is) as any other subwoofer, I would say even better as the cone breakup is higher than most subwoofers. The slow rise of 1/2db is easily compensated when using any lowpass. Wouldn't worry about it...

But I still need to find something that works well into 1.5 to 1.75cu ft net.
A single ported l26roy works in that size cabinet, which I wouldn't do but if you want it, if you would want to use as much space as you can for more bass, in a sealed configuration just add another l26 for more bass and your at the same internal size. This is the max spl you get for both configs (I would imagine that comparable woofers would simulate pretty similar) blue is 2x l26roy sealed and green one ported; The 2x sealed has more usable spl at frequencies often seen in most music.
1652223342089.png
 
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matt996

Member
2012-11-22 6:12 pm
Any thoughts on side mounted subwoofers? This can let me go up to a 12 inch, or even 15" if I really push it.
If you have miniDSP and are considering sealed, more displacement is your friend. Model it in your given box size to ensure you can drive it to xmax with the available power, and without exceeding the driver's thermal limit. Don't worry so much about Qtc since you can Linkwitz transform the response to the Q you want using DSP.
 

wasabii

Member
2021-11-30 10:48 pm
Op did you cross paths with these other Dayton 10's? https://www.parts-express.com/Dayto...eries-High-Excursion-Subwoofer-22-ohm-295-290

A couple in series with the Crown 1500 in stereo will do damage in and adequate sized and setup room. I don't know how they sound configured lower in to 2 ohms. They can do 2 but distortion might factor in to much. I mentioned the late model 1002? Its smaller but by no means short on power. The crown was a nice turn in the road to keep my hifi time busy. I was running out of things to do with it. I used to run big A/B amps for subs. One large full range A/B and A Pre with everything else is enough, time to be a bit easier on the hydro for a while. You can bet I'll be comparing the the Crown against a big 500 watt A/B on the subs though.

That Crown sounds great it would be nit picking for the most part. Strictly for curiosity sake :D
 
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wasabii

Member
2021-11-30 10:48 pm
I never did :-D
Wasabii did.

You ccould go slightly smaller to get a 0,7 Qtc max flat closed box but 0,6 is not much different (and goes slightly lower).


For me, he mentioned he wants 10s. 8's thats why I'm aiming for 4 to keep things happy happy. I still might opt for a couple of each. Which actually does help combat room nodes. Ive compared subs directly, one of each same maker and model. But many claim to know better regardless if they tried it or not. Its easy to make claims I suppose.
 

muad

Member
2010-08-26 2:19 am
I never did :-D
Wasabii did.

You ccould go slightly smaller to get a 0,7 Qtc max flat closed box but 0,6 is not much different (and goes slightly lower).
For me, he mentioned he wants 10s. 8's thats why I'm aiming for 4 to keep things happy happy. I still might opt for a couple of each. Which actually does help combat room nodes. Ive compared subs directly, one of each same maker and model. But many claim to know better regardless if they tried it or not. Its easy to make claims I suppose.
Sorry for the misunderstanding. I misread an earlier quote from STV... I didn't notice the word NOT before "going sealed with a smaller enclosure".
 

muad

Member
2010-08-26 2:19 am
The 2x sealed has more usable spl at frequencies often seen in most music.

I would love to 4x the l26roy, but it blows the budget. 2x the l26roy is at the top of what I can spend, but I would prefer sealed over vented.

Alternatively I could do 1x Rss315hf per side. The increased size would get me more spl out of a similar size box. It would have to be side mounted.
 

tim405

Member
2018-11-07 6:54 pm
Alternatively I could do 1x Rss315hf per side. The increased size would get me more spl out of a similar size box. It would have to be side mounted.
I have my doubts if they're really comparable, the rss315hf obviously has a bigger cone which helps with max spl etc. But I am not sure if the motor and design of the dayton is comparable to the seas, which might lead to high(er) distortion and non-linear behavior. Also the seas has a bigger magnet (positive), better basket design (small spokes and aerodynamic design) which helps against reflections and chuffing noise and also seems to have a bigger xmech thus maybe could even reach as much spl simply because it has more excursion capability. As I cannot find any independend testing results of the dayton this is pure (educated) guessing and I really cannot say anything more about it but I personally would rather have better behaving driver than a driver that has 3db more output (which I find not that much to be honest) so that may be something to consider too besides max spl.
 

muad

Member
2010-08-26 2:19 am
I have my doubts if they're really comparable, the rss315hf obviously has a bigger cone which helps with max spl etc. But I am not sure if the motor and design of the dayton is comparable to the seas, which might lead to high(er) distortion and non-linear behavior. Also the seas has a bigger magnet (positive), better basket design (small spokes and aerodynamic design) which helps against reflections and chuffing noise and also seems to have a bigger xmech thus maybe could even reach as much spl simply because it has more excursion capability. As I cannot find any independend testing results of the dayton this is pure (educated) guessing and I really cannot say anything more about it but I personally would rather have better behaving driver than a driver that has 3db more output (which I find not that much to be honest) so that may be something to consider too besides max spl.
The rss315hf has quite the reputation for sound quality rather than output. The thing is if it reaches a specific spl with less cone movement in a well designed driver, can't we assume the distortion is likely to be lower? Too bad there's no independent measurements for the daytons