Audioholics: please tell me if I’m crazy (for considering a subwoofer purchase)

[shadyJ]

Lets keep it really really simple!
Here is impulse response for JL Audio E112 which did not sound good:

Here is Impulse response for XS15se which did sound good (to my ear):

I don't know if the above data reflects what I hear or is just coincidental, but the sound quality of the PSA XS15 is better than the JL to me. I'll welcome you speculation as to why that might be.

Sorry, but you have pushed things back to frequency response again. What you are seeing in those impulse response graphs have a lot to to with the frequency response. Anything with a flattened out response, anything with a filter or lowered response would show the difference. People see impulse response and think they see some kind of prolonged ringing as though it were overhang, but that just the low end of the frequency response vs the high end. In fact, when I asked Josh Ricci whether I should include those in my subwoofer reviews, he said not to bother because they are so often misinterpreted.

Here is an example of how frequency response is reflected in impulse response:

This is an impulse response of the ULS-15 mk2, the green line is of EQ2 mode which has the characteristic sealed rolloff, and the purple line is in EQ1 mode where it is flat to 20 Hz followed by a steep rolloff. You can see that the green trace is very flat after 50 ms much like your XV15se graph. The difference is the frequency response and filter shape. The EQ1 mode does have more group delay due to the filter shape, but that isn't really what is seen in these graphs. You can't say one is better than the other. One just has more deep bass than the other.

Now here is a comparison of the ULS-15 mk2 in EQ2 mode, with the green line the same configuration as green in the above graph, but the difference is I just turned on the low-pass filter in the purple line:

Now you can see how smoothed out the response is, goodbye high frequencies, but if you look at group delay when the filter is activated, there is a lot more of it- as there always is with any electronically filtered system, and yes, that is what happens when you use bass management too. I guarantee you the same thing is happening in your system if you use bass management at all. So you aren't hearing what you think is impulse response at all. What you hear is frequency response. What people think sounds like 'tight' or 'fast' bass is usually just higher frequencies, or a greater ratio of high to low frequencies. If you want your subwoofer to sound totally tight to snobby audiophiles, just put a high-pass filter in line; they will think it sounds so 'musical'!

 

[shadyJ]

.. but I'm guessing that the PSA might be superior.

Guess again! Higher price does not always mean better performance!

 

[Henry Howards]

Guess again! Higher price does not always mean better performance!

I'd love to see the Audioholics test of the PSA S1500, which could provide me with a more objective basis for comparison. Unfortunately, there are only a few reviews available from professional audio test sites for many of the more recent PSA subwoofer models, and so I am left in the dark with questions of performance and value, relative to other subs.

 

[shadyJ]

I'd love to see the Audioholics test of the PSA S1500, which could provide me with a more objective basis for comparison. Unfortunately, there are only a few reviews available from professional audio test sites for many of the more recent PSA subwoofer models, and so I am left in the dark with questions of performance and value, relative to other subs.

I don't think Audioholics will be reviewing the S1500. If you want an idea of how the S1500 might compare, refer this chart to these measurements, ie tack just over 1 dB onto the data-bass measurements of the XS15se, and I think you can expect about that.

 

[Henry Howards]

If you want an idea of how the S1500 might compare, refer this chart to these measurements.

Thanks.

 

[KEW]

Your offer to set up a demo is genuinely appreciated, though a timely trip to Georgia just doesn't seem to be in the cards for me. I'm actually curious to hear a comparison between the S1500 and the Hsu ULS-15 MK2, but I'm guessing that the PSA might be superior. (Looks like Hsu has lowered the price on the Rosewood model, which makes me wonder how seriously I may allow myself to be swayed by a purely cosmetic feature...)
I imagine these models are essentially identical, it terms of what would be discernable to my hearing. For some (unscientific) reason I actually have a slight preference for the front-firing S1500. But the thought does occur to me that a down-firing sub might actually be better for creating more complex modes within a room. What is your opinion about this?
That is a deal-breaker for me. I'm already almost certain that I'm looking for a sealed subwoofer, as fine as that cylinder sub may be. Its 40" height also narrows down placement options to a single spot in my room, whereas a "cube" sub would allow me to experiment with as many as 5 different locations, a definite advantage.
That is EXACTLY what I want.
Your diligent advocacy is fine by me.
I can be even more extreme in this regard. Some movies have LFE that I find positively irritating, and it is not unusual for me to turn off the sound completely during those rumbustious scenes and just read the subtitles. I crave sonorous bass, rather than being bludgeoned by noise.

I would be interested in hearing your opinion on the servo control used in the Rythmik subs -- it makes a lot of sense to me. Do you believe it makes a significant contribution to improving the sound?
Thanks for all your advice -- I am finding it very helpful.

I too would love the chance to hear the ULS-15 vs S1500. I think the ULS-15 probably sounds more like the S1500 than it sounds different. I commented on the differences I am aware of between the Hsu and PSA here:
http://forums.audioholics.com/forums/threads/audioholics-please-tell-me-if-i’m-crazy-for-considering-a-subwoofer-purchase.106000/page-2#post-1163179

It is very much counterintuitive, but my Rythmik E15HP is front firing and my PSA XS15se is down firing. I have never noticed any difference in their behavior. Nor whether I am in front of or beside the Rythmiks. It seems like there would have to be a difference in how the sound waves radiate, but it is not audible (to me). Again, get Tom's opinion. Ask him why he introduced the front firing sub (which is also more prominently advertised it seems. I suspect he is simply catering to what his customers were asking for (regardless of whether it really mattered). But as long as the extra $100 isn't going to hurt you, get the one that "feels best" to you. Just as you would be foolish to simply buy the best looking sub in your budget without any consideration of sound, you would be foolish to totally ignore looks and the psychoacoustic influence of appearance. I can tell you that a sub (or speaker) which strikes you as ugly is not likely to sound so good as one that gives you pride of ownership (even if they have the exact same sound). Similarly, if your research allows you to feel comfortable with the Hsu, get the rosewood! The only time opting for looks is a mistake is when the sound quality takes a back seat to looks.

I did not realize that you had already pretty much settled on a sealed sub. I was not considering the $1200 SVS PC plus as a actual candidate for you so much as a ported sub that most people would agree is worthy of representing the characteristics of a quality ported sub. IOW, if the sealed PSA XS15se clearly sounded better to you than the SVS PC12 Plus you could have confidence that any other ported sub you try is unlikely to change your preference for sealed subs.

Your comments about preferences for HT sound make it pretty clear that you are not likely to want a ported sub.

I think the Rythmik servo is a nice feature. I consider the Rythmik E15HP to be the best sub I have heard. The PSA XS15se is its equal for music, but the Rythmik with its array of tuning controls is more capable of producing the LFE effects. That is not to say that the PSA fails at LFE. Since I have the Rythmik, I can notice where they put out more lows than the PSA. I am not sure how the more closely priced F12 would compete with the XS15se/S1500/15S.
The servo system allows Rythmik to get more out of the components they use than they otherwise would. The quality of the driver in the F12 is below what you would expect just as the 400 Watt amp is less powerful than you would expect in a $1000 (after shipping) sealed sub. Yet, the performance is very competitive and often better than other $1000 subs.
From what you have said, in addition to the PSA 15S/S1500, I would feel very comfortable recommending the Rythmik F12 to you. It has probably the most tuning options of any sub as "standard equipment".
Here is the quick guide for their amp controls:
http://www.rythmikaudio.com/download/A370PEQ_quickguide.pdf

 

[speakerman39]

Henry, as I mentioned much earlier in this thread the Hsu ULS 15 MK2 and the PSA S1500 were MUCH more alike than different. In the looks department the Hsu was just better. I have also owned a Hsu VTF 3.3 many years ago and it too was very nice to look at.

The ULS 15 MK2 was at least 95% or more of the S1500 over all. I did notice, however, the ULS 15 MK2 seemed to dig a little deeper as far as extension goes. But on the other hand, the S1500 was also a little bit tighter and/or faster to my ears. Again. none of which was a day or night difference. I honestly believe that you are merely splitting hairs here. You would NOT go wrong w/either one. I just believe that the ULS 15 MK2 is the better bargain period!

Cheers,

Phil

 

[Henry Howards]

The Hsu ULS 15 MK2 and the PSA S1500 are MUCH more alike than different. You would NOT go wrong w/either one.
Cheers,
Phil

Thanks. I admit I can be a hair-splitter, and a fence-sitter as well. I think I mentioned earlier in the thread that I researched the purchase of my current TV for over a year before I ultimately made the acquisition. It's also true that the "tell me if I crazy" clause in the subject heading for this thread is my way of wondering aloud whether it even makes sense for me to invest in a subwoofer at all. Consequently, I am looking at every option available to me with painstaking scrutiny, including the option of spending $1000 on Blu-ray titles instead of buying a sub. "Why not do both?" you might ask. The inconvenient truth is that I'm retired and I ain't flush. Buying 50-or-more Criterion Collection films might be a saner idea for me, personally, than seeking out those deep bass frequencies from 16 to 50 Hz. I'm still puzzling it out, and I absolutely appreciate all the good advice I have received from the folks on the Audioholics Subwoofer Forum.

 

[shadyJ]

Henry, as I mentioned much earlier in this thread the Hsu ULS 15 MK2 and the PSA S1500 were MUCH more alike than different. In the looks department the Hsu was just better. I have also owned a Hsu VTF 3.3 many years ago and it too was very nice to look at.

The ULS 15 MK2 was at least 95% or more of the S1500 over all. I did notice, however, the ULS 15 MK2 seemed to dig a little deeper as far as extension goes. But on the other hand, the S1500 was also a little bit tighter and/or faster to my ears. Again. none of which was a day or night difference. I honestly believe that you are merely splitting hairs here. You would NOT go wrong w/either one. I just believe that the ULS 15 MK2 is the better bargain period!

Cheers,

Phil

you were using the ULS in EQ1 mode, this balloons its low end considerably. Try it in EQ2 mode with Q set to 0.3 and then make your comparison. That response will be more like the S1500. I heard a S1500 in a medium large room, and it was barely there even when we blasted it. Admittedly the room probably overwhelmed it, but that kind of slope and design absolutely depends on room gain to work, otherwise it just lacks foundation. Earlier in this thread the SVS PC12-Plus was unfavorably compared to the S1500. In a small room the PC12 might get a lot of room gain, but you can always just plug its ports, and get a response that copes with room gain. In a medium to large room, the ported operation allows it a much greater frequency range than a sealed 15" like the S1500 and it will capture more music.

 

[shadyJ]

Thanks. I admit I can be a hair-splitter, and a fence-sitter as well. I think I mentioned earlier in the thread that I researched the purchase of my current TV for over a year before I ultimately made the acquisition. It's also true that the "tell me if I crazy" clause in the subject heading for this thread is my way of wondering aloud whether it even makes sense for me to invest in a subwoofer at all. Consequently, I am looking at every option available to me with painstaking scrutiny, including the option of spending $1000 on Blu-ray titles instead of buying a sub. "Why not do both?" you might ask. The inconvenient truth is that I'm retired and I ain't flush. Buying 50-or-more Criterion Classics titles might be a saner idea for me, personally, than seeking out those deep bass frequencies from 16 to 50 Hz. I'm still puzzling it out, and I absolutely appreciate all the good advice I have received from the folks on the Audioholics Subwoofer Forum.

Spending $1k on subwoofers when you aren't sure of what kind of bass you are after might be a bit misguided. I would suggest getting an inexpensive sub you can return for no cost if only to get a reference point on what kind of bass to expect. Barring that, I would get a ported sub that can be sealed, a la the VTF subs. That way its response can be made to accommodate your room no matter what. I think you will find a 15" isn't needed either, since you aren't after movie sound effects. I think a 12" would suffice. That will leave you with some cash to beef up your Criterion collection. You can even splurge on a box set like the Zatoichi set, which is fabulous. I purchased that last year and blew through all 25 films in a month, and I loved every minute of it. I can highly recommend the Zatoichi set. I am also interested in getting the Lone Wolf and Cub set, and hopefully that is in my future. I don't go after every Criterion, they are too pricey for that, but I have managed to accumulate a shelf full of gems from their collection.

 

[Henry Howards]

From what you have said, in addition to the PSA 15S/S1500, I would feel very comfortable recommending the Rythmik F12 to you. It has probably the most tuning options of any sub as "standard equipment".
Here is the quick guide for their amp controls:
http://www.rythmikaudio.com/download/A370PEQ_quickguide.pdf

Thanks for the Rythmik recommendation and the link. I'm going to start researching the Rythmik subs to get a better idea of what they have to offer. As you have said, their servo control might help an average-build subwoofer perform at a much higher level. I just noticed that they have even included the servo in their low-cost L12. It lacks the full array of amp controls available on the F12, but since it is half the price and a smaller footprint, I could buy 2 and perhaps benefit from better bass distribution throughout the room (while giving up some deep bass reach, in the bargain). I am discovering that, once again, reviews of Rythmik models from professional audio test sites seem to be all too rare (I have encountered this same scarcity of reviews for PSA models, as well) but I'm determined to keep looking.

 

[Henry Howards]

I would suggest getting an inexpensive sub you can return for no cost if only to get a reference point on what kind of bass to expect.

A valid point indeed. I am thinking that a very helpful experiment would be to order 3 Speedwoofer 10S models and place them in a Geddes arrangement. I can always return the Speedwoofer subs at no charge if the results are disappointing to me. I just found an hour-long YouTube video presentation by Earl Geddes on Multiple Subwoofers in Small Rooms. I haven't yet had the chance to watch the full video, but I'm definitely eager to hear what Geddes has to say on the subject.

I don't go after every Criterion, they are too pricey for that, but I have managed to accumulate a shelf full of gems from their collection.

I have had Criterion Collection titles waiting on my Amazon Wish List since early 2014 -- nearly 3 years. I believe this is what is known as delayed gratification...

 

[speakerman39]

you were using the ULS in EQ1 mode, this balloons its low end considerably. Try it in EQ2 mode with Q set to 0.3 and then make your comparison. That response will be more like the S1500. I heard a S1500 in a medium large room, and it was barely there even when we blasted it. Admittedly the room probably overwhelmed it, but that kind of slope and design absolutely depends on room gain to work, otherwise it just lacks foundation. Earlier in this thread the SVS PC12-Plus was unfavorably compared to the S1500. In a small room the PC12 might get a lot of room gain, but you can always just plug its ports, and get a response that copes with room gain. In a medium to large room, the ported operation allows it a much greater frequency range than a sealed 15" like the S1500 and it will capture more music.

Shady, I acknowledge that the ULS 15 MK2 could have been further tweaked. Nor, am I saying that the S1500 was that much better. But, rather that the S1500 was easier to get to the sound I was looking for. Even then, the differences were ONLY minor, but just slightly noticeable nonetheless.

I did not get around to taking any measurements. However, I did experiment around a bit w/placement. But, given that my room is so small placement choices were somewhat limited. In the end, I still say that the ULS 15 MK2 sub is the best sub in its price range all things being equal. The Hsu 15" vented offerings are also great deals. I just prefer a sealed design myself. The ULS 15 MK2 is a steal at the $808 shipped price inmho.

Cheers,

Phil

 

[KEW]

Sorry, but you have pushed things back to frequency response again. What you are seeing in those impulse response graphs have a lot to to with the frequency response. Anything with a flattened out response, anything with a filter or lowered response would show the difference. People see impulse response and think they see some kind of prolonged ringing as though it were overhang, but that just the low end of the frequency response vs the high end. In fact, when I asked Josh Ricci whether I should include those in my subwoofer reviews, he said not to bother because they are so often misinterpreted.

That makes total sense to me! However I (and others) come by it honestly. Most of us became acquainted with the impulse response as a metric for speakers where a quick reduction in SPL is indeed an indication of the "speed" of the speaker. It probably would make sense to drop it from subwoofer measurement.

Here is an example of how frequency response is reflected in impulse response:

This is an impulse response of the ULS-15 mk2, the green line is of EQ2 mode which has the characteristic sealed rolloff, and the purple line is in EQ1 mode where it is flat to 20 Hz followed by a steep rolloff. You can see that the green trace is very flat after 50 ms much like your XV15se graph.

Not really as quick to flatten out. The XS15se does it a little before 50ms and the ULS is about 20% slower at close to 60ms. However, that is not the way I would look at it. I would interpret the graph as showing that the XS15se was down to less than 10% of the initial signal in less than 10ms while it takes the ULS over 15ms to get below 20% and the ULS doesn't drop below 10% until 40ms!

The FR chart for the USL-15 Mk2 shown above has a maximum SPL of 91.8dB at 60Hz. From there it is down 5.4dB at 30Hz, and 15.4dB down at 20Hz, and falls below the graphs lower limit at 31.8dB down at ~13Hz.

The FR chart for the XS15se is from the Data-bass site. XS15se has a maximum SPL of 102.5dB at something like 110Hz. From there it is down 5dB at 30Hz, down 12dB at 20Hz, and down 21.5dB at 10Hz.

If we compare at the FR of the XS15se against that of the ULS in EQ2 mode, we see that the XS15se is producing more deep bass and quicker than the ULS. That contradicts what you are saying about the impulse response simply being a function of FR. There is more than just FR w/o deep bass giving the XS15se a quicker response than the ULS.

And, lastly, we can follow your suggestion and look at the Group Delay.
Here is the ULS-15 Mk2:

And we see that the ULS-15 is good, but the XS15se is better!

 

[KEW]

So you aren't hearing what you think is impulse response at all. What you hear is frequency response. What people think sounds like 'tight' or 'fast' bass is usually just higher frequencies, or a greater ratio of high to low frequencies. If you want your subwoofer to sound totally tight to snobby audiophiles, just put a high-pass filter in line; they will think it sounds so 'musical'!

I can accept that.
Josh Ricci (who provides the data for Data-bass) seems to think most people hear music as tighter if bass response is limited, not just "snobby audiophiles":

The fastest appearing impulse response will be from a system with no bass response at all. Same for most systems that sound tighter. Usually subjective differences are primarily due to loudness and response variations. The systems with less actual bass extension or response is often perceived as being tighter.

However, if adding bass above a certain level consistently undermines the perceived tightness of music, isn't avoiding that worthwhile? The live performances I attend (most often acoustic instruments with some mics) do not have that problem, so why should I have to listen to it on my home system?
Are you saying it is better to have the extra bass because we just think it sounds bad but it really doesn't???

Make no mistake, I enjoy the added sound of a sub when listening to music on most speakers. However, I do consider it optional with the Philharmonic 3's. Why is it that they sound tight at +/-2db @ 25Hz? For music, that is not at all bass-shy!

BTW, what subs do you currently have? Did you upgrade from the ULS-15's?

 

[shadyJ]

I would interpret the graph as showing that the XS15se was down to less than 10% of the initial signal in less than 10ms while it takes the ULS over 15ms to get below 20% and the ULS doesn't drop below 10% until 40ms!

I am glad to see you have done some homework on this matter! But remember this is not 'decay' in the sense that many people think it is. Deep bass has a longer duration in cycle time, and the greater the ratio of deep bass to higher frequencies, the longer you will see activity in an impulse response trace. This is exactly what you see happening in the impulse response for any of these type of charts. The ULS-15 mk2 has more deep bass output vs higher frequency output. Look at the 'full range response' chart in the XS15se review, this is really telling the story, especially above 200 Hz, where the Hsu rolls off, but the XS15se doesn't really roll off till 300 Hz. That is what you are seeing reflected.

If we compare at the FR of the XS15se against that of the ULS in EQ2 mode, we see that the XS15se is producing more deep bass and quicker than the ULS. That contradicts what you are saying about the impulse response simply being a function of FR. There is more than just FR w/o deep bass giving the XS15se a quicker response than the ULS.

The XS15se can only be considered 'quicker' in the sense that its base response, without any low pass filtering, looks to have proportionately more output at higher frequencies then the ULS-15 mk2. Once you apply a low pass filter, as probably everyone using one is doing, that is all gone. You still seem stuck on the idea that impulse response reflects some kind of group delay, which just isn't so. There isn't a really good explanation out there that I see which simplifies it, but here are a couple articles which at least discuss it: Wikipeidia and John Atkinson's measuring loudspeaker article. Here is another less formal discussion of it.

And, lastly, we can follow your suggestion and look at the Group Delay...

And we see that the ULS-15 is good, but the XS15se is better!

The delay in the ULS-15 is caused by a more aggressive high-pass filter, but that is irrelevant since group delay from either sub is totally inaudible. If I wanted to talk smack, I would say that the ULS is more linear in amplitude response, and is therefore a more accurate subwoofer, but the fact is that both group delay and amplitude response will radically change in room. The room acoustics dominates all of these qualities.

It seems to me you are looking for something that determines 'tightness' or 'quickness' in bass frequencies that goes beyond mere frequency response. The problem is, unless there is something horribly wrong with group delay of a speaker, that is all we are hearing. This is something that subwoofer manufacturers do not want to admit. They want that mystical 'air' surrounding their product which makes it more 'musical' (I loath that word in relation to speakers). This is, of course, nonsense. If a subwoofer or system of subwoofers can achieve a linear response, than it is a accurate system, period- and this can happen at a surprisingly low price point.

One more word about group delay: group delay would have been a bigger deal years ago when more subwoofers were tuned at higher frequencies. This means filters had to be active at higher frequencies, where group delay is more audible. You usually see it in systems with a rocky frequency response but usually not severe in systems with a flat response. It can also crop up in folded horn systems: an example is Josh's measurements of the DTS-10.

 

[shadyJ]

I can accept that.
Josh Ricci (who provides the data for Data-bass) seems to think most people hear music as tighter if bass response is limited, not just "snobby audiophiles":


However, if adding bass above a certain level consistently undermines the perceived tightness of music, isn't avoiding that worthwhile? The live performances I attend (most often acoustic instruments with some mics) do not have that problem, so why should I have to listen to it on my home system?
Are you saying it is better to have the extra bass because we just think it sounds bad but it really doesn't???

Make no mistake, I enjoy the added sound of a sub when listening to music on most speakers. However, I do consider it optional with the Philharmonic 3's. Why is it that they sound tight at +/-2db @ 25Hz? For music, that is not at all bass-shy!

There is a few things to unpack here.

First of all, we hear mid and upper bass so much better than deep bass. It takes human hearing longer to sense deep frequencies and longer to recognize pitch in low frequencies. In conventional music, there just isn't much of it, especially very deep bass where human pitch recognition is nil. A deep bass cycle take a lot longer to complete than a mid bass cycle; consider that a 20 Hz cycle takes ten times longer to complete than a 200 Hz cycle.

Now consider that a deep bass sound must be MUCH greater in sound pressure level than a mid bass sound to be heard as the same level of loudness. We are talking 100 times to over 10,000 times greater SPL depending on the mid bass amplitudes. Now factor in the tremendous amount of auditory masking that happens as we go down in bass frequencies. A speaker that simply omits deep bass sound will mask much less mid bass sound, and mid bass is much more easily discerned.

The 'detail' and 'articulation' people think they hear in bass frequencies is just mid and upper bass. It is only a matter of frequency response, nothing else. The more upper and mid bass you have, the more 'detailed' your bass sound will be, due to the nature of human hearing. Conversely the more deep bass you have, the less detail you will be able to hear. I don't want to put words in Josh Ricci's mouth, but I think this is what he might have meant. 'Tighter' bass is just more upper bass where sound is more easily distinguished.

I do think some subwoofers get a reputation for more 'detail' through the use of euphonic distortion; in other words, they are deliberately using even-order harmonic distortion products to elevate more easily heard upper bass sound over that of the fundamental in order to create the illusion of more detail. There is one brand of 'audiophile' subwoofer that I think may be banking on this tactic. I know that some older live-sound bass drivers used to deliberately generate second-order harmonics in order to goose up kick drum sounds.

It might be worth mentioning that a system that has deep bass might sound more 'laggy' than a system without due to things like flutter noise from some analog artifact, or maybe vinyl record rumble, or some low frequency noise that was accidentally boosted in compression the final mix but was missed by the sound engineer. A sound system that can reproduce deep bass is simply reproducing more of the input signal than a system that can not. In certain instances accuracy can come at the cost of musical content.

BTW, what subs do you currently have? Did you upgrade from the ULS-15's?

Still have the ULS-15 mk1s for my music system. There are better subs out there, but the mk1s do fine, I have a good response and enough headroom, so there is no need to replace them, as I wouldn't gain much. My theater uses two Outlaw Audio LFM-1 EXs and two Hsu VTF3 mk3s.

 

[KEW]

Thanks for the Rythmik recommendation and the link. I'm going to start researching the Rythmik subs to get a better idea of what they have to offer. As you have said, their servo control might help an average-build subwoofer perform at a much higher level. I just noticed that they have even included the servo in their low-cost L12. It lacks the full array of amp controls available on the F12, but since it is half the price and a smaller footprint, I could buy 2 and perhaps benefit from better bass distribution throughout the room (while giving up some deep bass reach, in the bargain). I am discovering that, once again, reviews of Rythmik models from professional audio test sites seem to be all too rare (I have encountered this same scarcity of reviews for PSA models, as well) but I'm determined to keep looking.

Every sub Rythmik makes has a servo.
I really cannot comment on the L12. It is a relatively new offering. I have never heard the F12 either, but it has been around for a long time and has a legacy as a very tight sub. I would have bought a pair of the F12's instead of the E15HP's except I planned to use them for HT and figured the 15" size would be useful, and I felt very safe buying the same sub that Jim Wilson bought after comparing them directly (in the same room at the same time) to the SVS SB13 Ultra. For music the F12 have a stellar reputation and are a popular choice.

 

[billy p]

Here is a related thread @ AVS...likely derived from what started here....there is no real way of measuring what makes a sub tight, articulate snappy or other hyperbole often used in describing sub sounds.


http://www.avsforum.com/forum/113-subwoofers-bass-transducers/2697241-what-best-measurement-subwoofer-tightness.html

 

[shadyJ]

...there is no real way of measuring what makes a sub tight, articulate snappy or other hyperbole often used in describing sub sounds.

Yes, there is a way of measuring it. The expertise given in that thread is quite clear about it. It is a matter of frequency response.