Aperion Audio Verus II Grand Tower Speaker vs SVS Ultra Towers (and others)

JStewart

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I must say John at Chane Music & Cinema was a pleasure to speak with. I was on the phone for over a half hour with him and he really took his time to explain their goals and design technologies regarding their new lines of speakers that are soon to be made public. I can't wait to see these speakers reviewed!!
I've also had the pleasure of sharing a couple of different email conversations with Jon. He is beyond helpful.
My hope is one of the 1st sets available for review will be heading to AV NIRVANA.
 

Kerry Armes

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Joined
Jan 10, 2019
Messages
24
Todd,
Thank you so much for the quick and thorough response, covering all my inquiries. You asked me about the rear port (I think that's the only port?) on the Ultra tower during the demo I heard. The port was open and I realize proximity to the back wall could possibly make the bass boomy and maybe that's what I was experiencing. This brings up something I read regarding ports and plugging them, that I'd like to run by you. A review I read on Audioholics By Steve Feinstein regarding RBH's R-55E:

"They have pretty good bass extension, definitely deeper and stronger than the B&W CM8 and Paradigm Prestige 75F. It’s a dual vented design; from my look inside the cabinet, all three woofers appear to share the same internal volume and the two rear ports serve to tune the entire bass section as one. Interestingly—and to RBH’s everlasting credit—there weren’t any foam cylinders included so the user could “plug one or more of the ports.” Many—too many—otherwise credible companies provide foam port plugs so the user can ostensibly change the speaker or subwoofer from a vented design to a sealed design.

That’s so bogus. A speaker designed to be vented can’t be made into a sealed speaker simply by plugging the holes. Not into a good sealed speaker. True acoustic suspension systems have drivers with completely different Thiele-Small parameters than a vented system. A real sealed system woofer has a far lower free-air resonance and higher compliance than a vented woofer, because in a real acoustic suspension system, it’s the trapped air spring in the sealed cabinet that provides the woofer’s restoring force, not the driver’s mechanical suspension (its surround and spider). If you simply take a vented woofer and block the holes, you’ll end up with a remarkably un-optimized system, with a far-higher bass cutoff than would be the case if it were an optimally designed AS system to begin with. I shake my head when I see vented systems offered with “port plugs.” RBH didn’t do that. Kudos to them."


Now I realize in the above quote he doesn't necessarily say it's a bad thing to do across the board, he only says it's bad regarding higher bass cutoff (which is exactly what I'm thinking you desired when blocking your Ultra's due to you running twin Ultra SB16's, and wanting tighter accurate bass, rather than extra SPL?) So, my question is do you think there's any other detriment to plugging ports, as far as negatively affecting the mechanical properties of the motor and acoustic suspension/excursion? Here's a quote from you regarding plugging the PB Ultra 16: Todd Anderson "I'm not sure how the PB16 would perform sealed. I'm fairly sure that that SB16 has some added DSP that helps to manage its output (that wouldn't be present on the PB16)... so you might get a slightly different result between the two if both were to be played sealed." Could what you said here also affect the Ultra tower in a similar way? (keep in mind I have no understanding of DSP you mentioned, I'm trying to learn)

Another question about porting. Why do most companies have rear firing ports? It seems to me from what I'm reading, rear porting can often cause issues with pragmatic positioning of towers in a multi purpose room such as a family room or main living room. I know I don't want my towers sitting 3 feet out into my family room, from the wall behind them, in order to avoid a boomy bass. Wouldn't front ports be more practical? I'm guessing the rear gives higher low frequency SPL, but what good is that if there's even just a nuanced hint of boominess? I'm probably missing plenty here, and that's why I'm running all this by you. I'll really appreciate hearing what you have to say about this.

Thank you so much. ps, if you want to move this to a different thread, that's fine as this started out with me asking about Aperion speakers that you reviewed, but has since changed topic.

Thanks again, Brian
Hi Brian,

I'm one of the owners of CSS. I found this thread from a backlink to our site (linked to my article about passive radiators) when looking at our analytics data so I stopped in to see what was being discussed. I saw this post (and a few others) and wanted to clarify a few things.


The information being provided by Steve Fienstein is not completely accurate and he seems to be confused on a few points and jumbling multiple things together. An acoustic suspension and sealed design are not the same thing, although they are often referred to as such. Acoustic suspension had specific requirements for woofers with very low fs and very lossy suspension as key components and used the air spring in the box to provide restoring force for the woofer rather than its motor and suspension. You can look up the patents related to it to get more info. So he’s right that you can’t make any ported speaker an acoustic suspension speaker. However, you can definitely turn any ported design into a sealed design by stuffing the port. How well it performs will depend on what you were expecting. The ported cabinet volume is likely a larger internal volume than I would use if I designed the speaker sealed in the first place, but it will still perform very similar to stuffing the port.


Steve seems to think these foam plugs are for marketing purposes only, so companies can say they are selling you a true sealed speaker or a true ported speaker in the same box and hit both crowds. What these plugs really do is restrict airflow out of the port and thereby reduce port output. It really ends up being somewhere in between a ported and sealed design.


But the real question is why would you want to do this, or why would companies include it. Well, the biggest reason is that not everyone has the same room and can’t place their speakers ideal distances from boundaries that reinforce bass or eliminate room modes in their system. If your speakers sound boomy in the lower bass, these port plugs reduce output and therefore will reduce boominess. It doesn’t mean that the ported design is flawed (although it could be). It just means that you are getting higher output than desired around port tuning. This is an easy way to let people adjust without any real consequences like buying new speakers or permanently modifying the ones you have.


Ported speakers tend to have more issues with boominess because room placement and because they extend deeper and might excite more room modes. Most normal rooms have a natural rise below a certain frequency (room size dependent) and so if your ported speaker extends to 40 Hz flat and your room starts its rise at 60 Hz, you could be +6 dB at 40 Hz in room. Now if you have a strong 40 Hz room mode, you might be even higher, which will also affect 80 Hz and 160 Hz. But if you have a speaker that is sealed with an f3 of 60 Hz, you would be flat at 40 Hz and the room modes would be less exaggerated.


Slight detour: One of the other posts here was discussing the benefits of front porting versus rear porting and asking about port placement close to a wall. Any speaker placed close to a wall that includes full baffle step will likely be boomy. It really won’t matter if it is front ported or rear ported. Close position to boundaries will reinforce bass frequencies and cause all sorts of bad interactions in the mid-bass and lower midrange. However, getting a port too close to the wall could restrict airflow and prevent you from getting full output from the port. It could also potentially lower your actual port tuning frequency. Ports also have resonant frequencies above the tuning frequency and many argue that having a front port might make these more audible. While the resonances are real and measurable, I’ve never seen any direct evidence from research to show that front porting makes them more audible than rear porting.
 

Kerry Armes

Member
Joined
Jan 10, 2019
Messages
24
Thanks, BadJRT.
Excellent article on speaker design. I like how they kept the information easy to follow, too : )
I'm glad you liked the article. We've got a bunch of other good ones on the website. I try to write all mine in a language that is easy to read and understand so hopefully someone at a beginner level can at least take away the main points. If you have other topics you'd like to see, drop us a line.
 

BadJRT

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Thread Starter
Joined
Dec 30, 2018
Messages
32
Location
Eagleville, PA
Hi Brian,

I'm one of the owners of CSS. I found this thread from a backlink to our site (linked to my article about passive radiators) when looking at our analytics data so I stopped in to see what was being discussed. I saw this post (and a few others) and wanted to clarify a few things.


The information being provided by Steve Fienstein is not completely accurate and he seems to be confused on a few points and jumbling multiple things together. An acoustic suspension and sealed design are not the same thing, although they are often referred to as such. Acoustic suspension had specific requirements for woofers with very low fs and very lossy suspension as key components and used the air spring in the box to provide restoring force for the woofer rather than its motor and suspension. You can look up the patents related to it to get more info. So he’s right that you can’t make any ported speaker an acoustic suspension speaker. However, you can definitely turn any ported design into a sealed design by stuffing the port. How well it performs will depend on what you were expecting. The ported cabinet volume is likely a larger internal volume than I would use if I designed the speaker sealed in the first place, but it will still perform very similar to stuffing the port.


Steve seems to think these foam plugs are for marketing purposes only, so companies can say they are selling you a true sealed speaker or a true ported speaker in the same box and hit both crowds. What these plugs really do is restrict airflow out of the port and thereby reduce port output. It really ends up being somewhere in between a ported and sealed design.


But the real question is why would you want to do this, or why would companies include it. Well, the biggest reason is that not everyone has the same room and can’t place their speakers ideal distances from boundaries that reinforce bass or eliminate room modes in their system. If your speakers sound boomy in the lower bass, these port plugs reduce output and therefore will reduce boominess. It doesn’t mean that the ported design is flawed (although it could be). It just means that you are getting higher output than desired around port tuning. This is an easy way to let people adjust without any real consequences like buying new speakers or permanently modifying the ones you have.


Ported speakers tend to have more issues with boominess because room placement and because they extend deeper and might excite more room modes. Most normal rooms have a natural rise below a certain frequency (room size dependent) and so if your ported speaker extends to 40 Hz flat and your room starts its rise at 60 Hz, you could be +6 dB at 40 Hz in room. Now if you have a strong 40 Hz room mode, you might be even higher, which will also affect 80 Hz and 160 Hz. But if you have a speaker that is sealed with an f3 of 60 Hz, you would be flat at 40 Hz and the room modes would be less exaggerated.


Slight detour: One of the other posts here was discussing the benefits of front porting versus rear porting and asking about port placement close to a wall. Any speaker placed close to a wall that includes full baffle step will likely be boomy. It really won’t matter if it is front ported or rear ported. Close position to boundaries will reinforce bass frequencies and cause all sorts of bad interactions in the mid-bass and lower midrange. However, getting a port too close to the wall could restrict airflow and prevent you from getting full output from the port. It could also potentially lower your actual port tuning frequency. Ports also have resonant frequencies above the tuning frequency and many argue that having a front port might make these more audible. While the resonances are real and measurable, I’ve never seen any direct evidence from research to show that front porting makes them more audible than rear porting.
Hello Kerry,
Thank you so much for elaborating on some of my inquires. I'd like to ask a few more questions but I don't have time to write them out right now.(Hopefully this weekend) I just wanted to let you know I read your posts here and really appreciate you taking the time to explain some of these things to a guy who's not very knowledgeable, but trying to learn all I can before I start building my system.

Thanks again, Brian
 

Kerry Armes

Member
Joined
Jan 10, 2019
Messages
24
Hello Kerry,
Thank you so much for elaborating on some of my inquires. I'd like to ask a few more questions but I don't have time to write them out right now.(Hopefully this weekend) I just wanted to let you know I read your posts here and really appreciate you taking the time to explain some of these things to a guy who's not very knowledgeable, but trying to learn all I can before I start building my system.

Thanks again, Brian
No problem
 
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