Some thoughts on the ported vs sealed debate

[caioferrari]

Bought a KEF Kube 12b, waiting for the package.
I’m happy to have auto-on feature and a smaller system. I’ve never been a fan of too many external gears that gives a bigger footprint and needs to be manipulated every time I’m going to listen my songs.

 

[caioferrari]

Guys, the KEF is here.
It’s impressive how powerful it is. Sometimes its too much bass, doesn’t seem less powerful than my other sub witch has 1500 W.

I had some problem with the limiter. The sub volume was too high and the amp was turning off to protect the driver. I saw that even on 50% Audissey set its volume to -12 dB, the minimum allowed By receiver software.

About the sound, I got a pretty decent response and a little boom on certain frequencies that I need to figure out. Seems that the sound is a less damped than my sub on sealed mode, but more damped than my old one on ported mode.

I’m attaching its frequency reponse

 

[lovinthehd]

Guys, the KEF is here.
It’s impressive how powerful it is. Sometimes its too much bass, doesn’t seem less powerful than my other sub witch has 1500 W.

I had some problem with the limiter. The sub volume was too high and the amp was turning off to protect the driver. I saw that even on 50% Audissey set its volume to -12 dB, the minimum allowed By receiver software.

About the sound, I got a pretty decent response and a little boom on certain frequencies that I need to figure out. Seems that the sound is a less damped than my sub on sealed mode, but more damped than my old one on ported mode.

I’m attaching its frequency reponse

You can't compare amp wattage alone as an indication of the output of the sub, fwiw. If your avr is setting the sub level to -12 that means you have the gain on the sub set too high still (and the avr can't compensate further), turn it down and re-run Audyssey until it is -11.5 or better (50% is just a guess at a starting point). Did you try a sub crawl for placement or ?

 

[caioferrari]

You can't compare amp wattage alone as an indication of the output of the sub, fwiw. If your avr is setting the sub level to -12 that means you have the gain on the sub set too high still (and the avr can't compensate further), turn it down and re-run Audyssey until it is -11.5 or better (50% is just a guess at a starting point). Did you try a sub crawl for placement or ?

I know I can’t, but in this case the power is so different (1500 vs 300 W) that was impossible not mention that.
I’m not using Audissey, I just ran to set the speaker distances /delay.
I didn’t understand the last thing you said. About the sub crawl. I tried to translate and even so I didn’t get it.

 

[lovinthehd]

I know I can’t, but in this case the power is so different (1500 vs 300 W) that was impossible not mention that.
I’m not using Audissey, I just ran to set the speaker distances /delay.
I didn’t understand the last thing you said. About the sub crawl. I tried to translate and even so I didn’t get it.

Without knowing the sensitivity of the system hard to know what the amp wattage can produce. If the sub is 84 dB sensitive vs one that is say 92 dB sensitive, 300 W on the 92dB sub would be equivalent to almost 1900W on the 84dB sub....

You arbitrarily set the sub trim level to -12 with sub gain set to 50%?

Sub crawl is a way to determine better placement of sub, try this article https://www.audioholics.com/home-theater-connection/crawling-for-bass-subwoofer-placement

 

[caioferrari]

You arbitrarily set the sub trim level to -12 with sub gain set to 50%?

No. I ran Audissey, got the the distances and saw the levels. After that, I turned off the Audissey eq and ajusted the sub level measuring the FR

 

[lovinthehd]

No. I ran Audissey, got the the distances and saw the levels. After that, I turned off the Audissey eq and ajusted the sub level measuring the FR

Sub level/distance can be affected by the particular dsp used in the sub.....altho sometimes using DynEQ with Audyssey can be nice at lower volumes in any case. Maybe more about how you measured/adjusted sub level could be interesting....

 

[shadyJ]

Hsu Research might be the only honest manufacturer regarding this debate. From a new article they have posted:
"Sealed subwoofers are the design choice of many stereo channel audiophiles. Their thought is that ported subwoofers or passive radiators are not quick enough. However, we believe that, perceptively, a well-designed ported subwoofer can be perceived as fast and accurate as a sealed subwoofer, and things like room acoustics, etc are usually the main culprit behind perceived boominess."

I haven't seen any other manufacturer say that. Most just regurgitate the 'sealed is faster/tighter/chocolatier' audiophile myth.

 

[isolar8001]

'sealed is faster/tighter/chocolatier'

Wait....I can get chocolate out of my RSL's if I plug the ports ??
I drink Hershey's Syrup right out of the bottle, so this is one hell of a revelation !!!!

 

[Steve81]

Hsu Research might be the only honest manufacturer regarding this debate. From a new article they have posted:
"Sealed subwoofers are the design choice of many stereo channel audiophiles. Their thought is that ported subwoofers or passive radiators are not quick enough. However, we believe that, perceptively, a well-designed ported subwoofer can be perceived as fast and accurate as a sealed subwoofer, and things like room acoustics, etc are usually the main culprit behind perceived boominess."

There’s that not so minor caveat popping up again Remember the original SVS subs? Those things were case studies in how to build non-musical ported subs. IIRC, they struggled to get up to even 80Hz.

Also, is Dr. Hsu suggesting that sealed subs aren’t affected by room acoustics, or that they’re a better match to most rooms vs ported subs?

 

[HTEnthusiast]

I have 2 HSU ULS-15s (sealed) and 2 RSL12s.(ported). I had to level match and time them with a miniDSP, but feel like I’m getting the best of both worlds.

However, I feel like I’m getting the best of 2 manufacturer’s designs vs a ported/non-ported reason. My neighbor has 2 HSU VTF-3 MK5 (ported) in his system. From my listening to both, I hear that the 2 HSU (ported & non-ported) subs are more sonically similar than either HSU compared to the RSL12S. The VTF-3 MK5s go low, but they sound and feel completely different.

Both types of HSU subs have more body and volume, but they both lack the super tight speed of the RSL. I didn’t get that impression of the HSUs until I picked up the RSL12S. The RSL12S is incredibly fast and low, but lack that little bit of body in the HSUs. If I had to choose between them, I would most likely rather have the RSL. That is only because once I got used to the clean speed, it’s something I wouldn’t want to go away. Thankfully, I was able to get them setup where they are working in a complimentary fashion. The bass is fast, tight, and has that little extra “weighty” feel.

It’s a somewhat risky endeavor to try and mix sub types, however, as I have tried the same exercise with OSD Black Trevoce 12EQ subs. I could never get them to work together, with either the ULS or RSL. There was always some type of cancellation going on at some frequency when combined that couldn’t be avoided. My initial thoughts are that it’s due to the OSDs design that has 1 active and 2 passive drivers, but who knows.

 

[shadyJ]

I have 2 HSU ULS-15s (sealed) and 2 RSL12s.(ported). I had to level match and time them with a miniDSP, but feel like I’m getting the best of both worlds.

However, I feel like I’m getting the best of 2 manufacturer’s designs vs a ported/non-ported reason. My neighbor has 2 HSU VTF-3 MK5 (ported) in his system. From my listening to both, I hear that the 2 HSU (ported & non-ported) subs are more sonically similar than either HSU compared to the RSL12S. The VTF-3 MK5s go low, but they sound and feel completely different.

Both types of HSU subs have more body and volume, but they both lack the super tight speed of the RSL. I didn’t get that impression of the HSUs until I picked up the RSL12S. The RSL12S is incredibly fast and low, but lack that little bit of body in the HSUs. If I had to choose between them, I would most likely rather have the RSL. That is only because once I got used to the clean speed, it’s something I wouldn’t want to go away. Thankfully, I was able to get them setup where they are working in a complimentary fashion. The bass is fast, tight, and has that little extra “weighty” feel.

It’s a somewhat risky endeavor to try and mix sub types, however, as I have tried the same exercise with OSD Black Trevoce 12EQ subs. I could never get them to work together, with either the ULS or RSL. There was always some type of cancellation going on at some frequency when combined that couldn’t be avoided. My initial thoughts are that it’s due to the OSDs design that has 1 active and 2 passive drivers, but who knows.

I have lots of experience with both Hsu and RSL subs, and the differences you describe aren't what I perceived (it's not supported by the respective time-domain measurements for these subs either). Then again, I have never heard 'tight' or 'fast' subwoofer-range bass in my life, despite having closely listened to and measured dozens of subs. I have heard boomy bass and many different types of subwoofer distortion of both linear and nonlinear varieties, but I have never heard anything below 100Hz that I would say has "super tight speed."

 

[HTEnthusiast]

I have lots of experience with both Hsu and RSL subs, and the differences you describe aren't what I perceived (it's not supported by the respective time-domain measurements for these subs either). Then again, I have never heard 'tight' or 'fast' subwoofer-range bass in my life, despite having closely listened to and measured dozens of subs. I have heard boomy bass and many different types of subwoofer distortion of both linear and nonlinear varieties, but I have never heard anything below 100Hz that I would say has "super tight speed."

That’s interesting. I have a pair of Magnepan 1.6QRs that I now have sitting in the storage area replaced by a cone speaker for my mains. The difference I hear in the HSU vs the RSL12S is somewhat akin to the difference between the Magnepan and cone speaker. The HSU being more like the Magnepan, and the RSL being more like the cone speakers I have now. My son in law came over yesterday. He has a home theater setup and has been running sound for churches for a long time. He explains the difference after adding the RSLs as sounding more “clean, detailed and lower”.

It’s a shame we can’t just run over to each others’ setup. You may just be describing the difference in an alternate way. Here is the difference In the REW graphs between the 2 subs, then a third that has them combined. This is before any manual house curve adjustments. I tried an exhaustive exercise of different placement differences, and the basic curves for both the RSLs and the HSUs don’t change appreciably with position. I have a pair of both, so I played around with 4 subs. Adding a second of the same type sub helped a little bit when placed in opposite corners, but it more increased the same curve up a few db.