SUBFEST 2011-HuskerOmaha and Desertdome's Subwoofer Showdown - Page 6

Thanks for the donations too. It seems like a very useful tool.

With all these really bad reviews of the F20 I'm really glad I didn't build one :/

It has its place if you just enjoy bass for the sake of bass, seems like there was just bass the whole time, never a quiet moment. I would recommend it for many of my friends who just enjoy the presence of sound.

I've seen similar dips with certain placements in rooms, and most often such an artifact goes away with another placement. I suspect moving near another wall would smooth this quirk in the response, but it's still there in the DTS 10 which was on the right wall, so it's not quite that simple. Of course it was consistent for most all of the subs and the rest of the range worked pretty well for a set pair of locations at the front.


Agreed generally. My point was that the drop at the dip pushed the lowest frequencies into the noise floor, making it tough to directly compare the roll off of 18.2 & VS18.


For the purpose of matching the useful range of the subwoofer the measurement showed plenty. There is not enough information to critically compare the extents of the roll off, as the noise floor down will make the lower frequencies less accurate when the level gets too far below the target level. None of us would suggest boosting the in-room response by more than 20dB anyway, so it didn't have any significant impact the EQ efforts the measurements were used for.


You might have mistaken my intended point, as I don't disagree with you. In reference to the questions about the apparent similarity of the roll off between the SS-18.2 and the VS-18, the kink/dip in the room's transfer curve pushed the frequency response closer to the noise floor below ~15Hz. Combine that with possible VLF differences with the second subwoofer on the right of the center when dual VS-18s were used, and there are too many variables to clearly see what was happening with the roll off between these two.

i was pretty excited about this thread and the good data...until i got to page 2. like bosso says, the post eq setups between the seaton and the cht are so different, i'm not sure what you guys were actually comparing. as they are both sealed, why weren't they eq'd similarly?

I suppose I'm just a dolt here amongst experts (not the first time, lol) but I'm still scratching my head while attempting to figure how including duals and singles in one comparo is beneficial in any way.

One, since output didn't seem to be an aim, I can understand how that was a non issue. No problem there- even though it seemed at least two alluded to the fact that some subs couldn't make the "reference levels" that were being sought.

Bit contradicting, there. One, certainly a unit like the Cap would not likely be in that category amongst the other subs present, and 2 (and much more importantly) why not simply lower the listening level "x" number of dbs to allow all the subs to compete evenly if it's simply (majorally) about sound quality? Again, I'm confused.

Two, don't two subs inherently increase the ease/likeliness of more linear response (read: better sound)? Thus giving duals an inherent sound quality advantage over a single of another?

Three, perhaps I need to re-check to see if duals were the MAJORITY and not the MINORITY. I know there was only one SubM, lol. Then I could more easily understand the use of pairs.

I realize there's no ideal comparison. And differences between differing designs, sizes, and cost are to be expected, but doesn't including doubles vs singles simply (and unnecessarily) muddy the waters?

I'm going to guess Ill be told "no" (again), but I've never read a sub shootout/listening audition/whatever that was orchestrated quite like this.

Do I think it's the end of the world and makes the GTG worthless? Absolutely not.

Is is hard for me to believe- or to put it better- understand how it doesn't (at least to some degree) adversely affect/alter these auditions against single subs? Absolutely.

Bear with me please!

James

WOW... Did I miss something!

I thought that the SubM were duals...it was a single sub?? (I rescind my statement above.) And it produced THAT flat of a response? It actually doesn't seem believable.

Husker, your room must be some sort of miracle room. The more I look at the FR of the subs, I wonder how in the world the single subs don't show any significant nulls, modes, etc (at least to my amateur eyes). It's rare to find that EQ alone can make it flat as the FRs you measured from those subs. Generally speaking, singles or duals, they were within a 6db range..., that's pretty incredible. Your room almost seems like duals don't add a significant advantage to the 1 prime listening position which is completely counter intuitive to what I've learned over the years!

I'm amazed. It makes sense now that for those sitting in the FR measured LP why perhaps the single SubM topped things, but I have to guess if you moved away from the optimal locations, any comparable dual setup would win by a landslide based on a flatter response. Perhaps the 'brand' did have significant influencing.

Does anyone else find this strange?

I'm right there with you James...

Regarding the comments or lack there-of about the VLF content...

I've listened to most of these scenes more times than I care to count with a wide range and scale of subwoofers, especially scenes like Master & Commander. I generally listened from the same area to the left of desertdome and behind HuskerOmaha. While there are many subtle variations within these groups, I heard two dominant areas of notable differentiation between subs.

To me, the low tuning and in-room extension differences were readily apparent having played around with various high passing or not and differently tuned subwoofers on many of the scenes before. Obviously this wasn't as directly noted by listeners as other qualities. Without a bit of experience in what different ranges added or subtracted to the experience, I think some were looking for the words to express what they heard, and/or the "loud & low bass" region in the 25-35Hz range was often lumped together with deeper content. Indeed, doubling the SubMersive HP or quadrupling the Rythmik would have been more fun in this regard and made differences more obvious. The ported Turbos, Captivator and VS-18s all have similar tuning frequencies, making distinction of the low extension less apparent as other differences with the sealed designs made for more obvious differences.

With the response smoothed to the target curve and the more obvious differences in ground plane/anechoic responses it was possible to hear the different fingerprints and qualities of the various designs. IMO, the nature by which each design changes when driven harder and design factors which affect distortion vs. frequency and level were audible and listeners did react to them even if they might not have correlated the exact causes for such differences. The F20 is the extreme example, where it had tons of output but sounded a bit resonant and lumpy. The Rythmik was the antithesis of it.

Detailed measurement efforts like those of Keith Yates, Ilkka and Ricci report on a lot more than the frequency response at a single level for very good reason, and many of those reasons relate to the differences heard. Of course the frequency response matters greatly as well, and unless you are measuring yourself, you can also expect to also hear the effects of the differing no-EQ measurements posted here by desertdome. Very few comparisons I've seen done to date have had anywhere near this type of effort put into better matching the frequency responses between subwoofers. There are plenty of differences in real use beyond the low level frequency response, but there's no question the ground plane frequency response differences between products play a notable role in preferences and subjective impressions.

I completely understand and appreciate this explanation, thank you.

Does it completely remedy my thoughts that ALL (or all but one, perhaps ) of the subs couldve been similarly eqd (single units) and played between 75 and 85dbs for the purpose of SQ comparison? Well, no.

But more importantly, it pretty much (to me anyway) attempts to even the playing field of products that are completely incongruent...from a size and price pov, especially.

I would say run the singles within their respective limits and let the rather informed enthusiasts here make their own logical deductions in regards to the aforementioned factors rather than this approach- but that's completely my opinion, obviously.

Most crucially though, just as Mark said, there's no perfect way to do this...especially under these time constraints, so I'm again appreciative and respectful of what we did get.

Thanks again all!

James

I think Dr. S had a good point that has kind of gotten lost, perhaps because of the numerical ratings that followed:


So I think the ratings and commentary need to be taken with a grain of salt, since this was first and foremost a meet for enthusiasts to get together and hear a bunch of different subs that they otherwise might never get to hear, and form more personal opinions than they could otherwise form. The rest of us just get to leech our impressions based on what we read.

Although some variables were controlled (such as attempting to normalize levels and sub FR), there were a lot of uncontrolled variables that could color the results / impressions:

• seat to seat FR variation (versus EQ optimized for a single mic location)
• some single subs, some dual
• effect of the room itself
• subs were positioned differently I believe (not all in the same location)
• Some of the subs were DIY

I just noticed stormwind put his comments up. I'd like to see Desertdome put his subjective comments up too! Only a few more now.

DesertDome, I've had the chance to digest some of your work in this thread and its impressive. Thanks for all you did for the meet!

My F-20's had horrible upper bass resonances as well. I EQ'd them flat and they were gone. Again I listen mostly to movies and the music I listen to sounds great but I have 4 and I can't find their limits in my room which is 2200 cubes and very well treated.

Take another look at the pictures like these two:

and


The addition of the 2nd subwoofer on the opposite side of the center channel will only affect width modes, and have exactly the same interaction with the vertical and length dimensions of the room. I have always found such placement to look rather similar for most rooms (there are exceptions). The pair can make for a little less or different variation in upper frequencies as you move across the listening positions, but based on my own experience, this is typically not a large difference. The biggest benefit from multiple subwoofers comes from significant separation of say 1/4-1/2 each side wall or one toward the front and another toward the rear or 1/2 back in the room. This is in fact one of the more common problems that crops up in rooms with false screen walls where all subs are in front. The best results come from adding at least one sub that is not behind the wall.

Also go back (or below) and look at the SubMersive's response before and after EQ, where you can clearly see the ~7dB recession in the response that is similarly present in all of the measurements. You can also see the quirk in the mid teens which affected all of the subs as well as a dip in the 75Hz range which moved a little with different sub sizes and positions. As others have noted the 90Hz null found in the SubMersive and 18.2 is not in other measurements. I suspect this is related to the subs being a little closer to the front wall due to config, where such differences tend to affect the upper end of the sub response and not much else.

Having this subwoofer GTG makes me want to host a home theater GTG where we change out mains too.

For me looking at the results it's not just about SQ, but also composure at reference level and general output capabilities. For instance, what I got out of the comments and measurements is that at reference levels a single SubM is an awesome sub that measures fantastic and generally betters multiples of less expensive subs from a subjective standpoint and conversely that less expensive multiples, for example the CHT's(because I own them), can deliver a very satisfying experience that in some instances can subjectively match a single SubM but overall is a notch below. I can extrapolate what I think the results of dual SubM's would have been, and that would likely have been a clear extension of the SubM's subjective lead across the board. The dual Captivators clearly have reserves for above reference playback and are great performers, but again, less expensive duals can provide for a close reference level experience for those that cannot afford the cost.

That IMO is great information. It makes me feel comfortable that the dual CHT 18.1's I currently have in my room are giving me excellent performance. Not the best, but respectable until I'm ready to make the move to the Captivators, SubM's or DIY. I can't be the only one that has sat through a movie and wondered how much better it might be if I upgraded to better subs. This GTG gave me some insight as to what I should expect when I do upgrade, so for that reason I think it was a resounding success even if it was not "perfect".

I think the easiest way to have a blind study would be if you had a perforated screen and the subs were behind a screen wall. I run a perforated screen myself, but I do not have a separating wall.

You just spoke for me. I can just imagine what a Submersive sound and feel like given how much I miss my Empire. Really looking forward to Chase's new offerings. Yeah I know a Ricci hands on with the Submersive would be great. Subjective feedback from knowledgeable folks isn't bad either. This is an awesome thread for perspective.

I was actually going to bring a blindfold or pillow case for my head haha. The problem is that Michael would of had to carry each sub by himself and set it up to the owners preference . Would of been fun to bring subs back out after for round two. Dennis and I hopefully will be chaperoning the Rythmik and CHT SS on a date Saturday. I hope they get along together but I swear if the CHT tries turning up the Rythmik too much to get a better look, it's off .

Yours is a tough act to follow. I agree with you that bias is an issue in any sighted comparison but as someone else said, at least we can extrapolate from your GTG. It was thoughtfully done and must have been a LOT of work. Well done!

Chris

Just that due to seat to seat variations, not everyone was hearing the same thing, which could impact their subjective impressions of each sub. Although now that I think about it, if people kept their same seats throughout, I guess they'd have the same bias for each sub.

Did those in the seats closest to the mic / EQ position tend to have higher scores across the board, or not really?

in place of this subjective slop (no offense folks), why not just send some subs to an objective third party for testing?

seaton, chase, permanian, send your best sh_t to ricci for an objective test. bosso, why don't you jump in with your best stuff? that would make for a serious comparo...:-) eq'd the same, i'd bet it would all be to tough to call beyond the simple physics of driver design, but who knows, maybe magic exists ;-)...

That's a great idea too, but measurements are not the last word on SQ. For example, I've yet to see measurements that could help me distinguish the SQ difference between ported or sealed subs or measurements that could reliably tell me what sub might sound "tighter" or conversely "bloated" compared to another. These are subjective qualities for which I'm sure some measurement could quantify objectively to make subjective evaluation unnecessary, but what are those measurements?

great point good doc. we'd have to have the right measurements and that is still not clear. in a world where we don't know what to measure, the subjective scores have their place...so frustrating...

The more I learn and grow in subwoofer knowledge, the sillier I feel about any "conclusion" I've ever posted.

I'd be open to hosting any future GTG. Greenville, SC is central to most of the Southeast. I have no abilities to conduct it, but have a great place for hosting. Keep it in mind if anyone wants to take the reigns.

This is what always bothered me about graphs. I have owned a few SVS and HSU subs that looked good on a graph. They were great subs but were not my taste. Can one graph taste? Imagine the many variables from one listener to another. Also, I think there is some reverse psychology at work here. Some folks tend to love subs "after" they see a great graph. Maybe graphs lead one to marginalize a product. Again, not saying there aren't benefits to graphs.

I thought Craig was sending a unit to Ricci (or that was the rumour eons ago?).